2 * Copyright © 2014 Red Hat
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that copyright
7 * notice and this permission notice appear in supporting documentation, and
8 * that the name of the copyright holders not be used in advertising or
9 * publicity pertaining to distribution of the software without specific,
10 * written prior permission. The copyright holders make no representations
11 * about the suitability of this software for any purpose. It is provided "as
12 * is" without express or implied warranty.
14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
23 #include <linux/delay.h>
24 #include <linux/errno.h>
25 #include <linux/i2c.h>
26 #include <linux/init.h>
27 #include <linux/kernel.h>
28 #include <linux/sched.h>
29 #include <linux/seq_file.h>
30 #include <linux/iopoll.h>
32 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
33 #include <linux/stacktrace.h>
34 #include <linux/sort.h>
35 #include <linux/timekeeping.h>
36 #include <linux/math64.h>
39 #include <drm/drm_atomic.h>
40 #include <drm/drm_atomic_helper.h>
41 #include <drm/drm_dp_mst_helper.h>
42 #include <drm/drm_drv.h>
43 #include <drm/drm_print.h>
44 #include <drm/drm_probe_helper.h>
46 #include "drm_crtc_helper_internal.h"
47 #include "drm_dp_mst_topology_internal.h"
52 * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
53 * protocol. The helpers contain a topology manager and bandwidth manager.
54 * The helpers encapsulate the sending and received of sideband msgs.
56 struct drm_dp_pending_up_req {
57 struct drm_dp_sideband_msg_hdr hdr;
58 struct drm_dp_sideband_msg_req_body msg;
59 struct list_head next;
62 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
65 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
67 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
69 struct drm_dp_payload *payload);
71 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
72 struct drm_dp_mst_port *port,
73 int offset, int size, u8 *bytes);
74 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
75 struct drm_dp_mst_port *port,
76 int offset, int size, u8 *bytes);
78 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
79 struct drm_dp_mst_branch *mstb);
82 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
83 struct drm_dp_mst_branch *mstb);
85 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
86 struct drm_dp_mst_branch *mstb,
87 struct drm_dp_mst_port *port);
88 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
91 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
92 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
93 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
95 #define DBG_PREFIX "[dp_mst]"
97 #define DP_STR(x) [DP_ ## x] = #x
99 static const char *drm_dp_mst_req_type_str(u8 req_type)
101 static const char * const req_type_str[] = {
102 DP_STR(GET_MSG_TRANSACTION_VERSION),
103 DP_STR(LINK_ADDRESS),
104 DP_STR(CONNECTION_STATUS_NOTIFY),
105 DP_STR(ENUM_PATH_RESOURCES),
106 DP_STR(ALLOCATE_PAYLOAD),
107 DP_STR(QUERY_PAYLOAD),
108 DP_STR(RESOURCE_STATUS_NOTIFY),
109 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
110 DP_STR(REMOTE_DPCD_READ),
111 DP_STR(REMOTE_DPCD_WRITE),
112 DP_STR(REMOTE_I2C_READ),
113 DP_STR(REMOTE_I2C_WRITE),
114 DP_STR(POWER_UP_PHY),
115 DP_STR(POWER_DOWN_PHY),
116 DP_STR(SINK_EVENT_NOTIFY),
117 DP_STR(QUERY_STREAM_ENC_STATUS),
120 if (req_type >= ARRAY_SIZE(req_type_str) ||
121 !req_type_str[req_type])
124 return req_type_str[req_type];
128 #define DP_STR(x) [DP_NAK_ ## x] = #x
130 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
132 static const char * const nak_reason_str[] = {
133 DP_STR(WRITE_FAILURE),
134 DP_STR(INVALID_READ),
138 DP_STR(LINK_FAILURE),
139 DP_STR(NO_RESOURCES),
142 DP_STR(ALLOCATE_FAIL),
145 if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
146 !nak_reason_str[nak_reason])
149 return nak_reason_str[nak_reason];
153 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
155 static const char *drm_dp_mst_sideband_tx_state_str(int state)
157 static const char * const sideband_reason_str[] = {
165 if (state >= ARRAY_SIZE(sideband_reason_str) ||
166 !sideband_reason_str[state])
169 return sideband_reason_str[state];
173 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
178 for (i = 0; i < lct; i++) {
180 unpacked_rad[i] = rad[i / 2] >> 4;
182 unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
185 /* TODO: Eventually add something to printk so we can format the rad
188 return snprintf(out, len, "%*phC", lct, unpacked_rad);
191 /* sideband msg handling */
192 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
197 int number_of_bits = num_nibbles * 4;
200 while (number_of_bits != 0) {
203 remainder |= (data[array_index] & bitmask) >> bitshift;
211 if ((remainder & 0x10) == 0x10)
216 while (number_of_bits != 0) {
219 if ((remainder & 0x10) != 0)
226 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
231 int number_of_bits = number_of_bytes * 8;
234 while (number_of_bits != 0) {
237 remainder |= (data[array_index] & bitmask) >> bitshift;
245 if ((remainder & 0x100) == 0x100)
250 while (number_of_bits != 0) {
253 if ((remainder & 0x100) != 0)
257 return remainder & 0xff;
259 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
262 size += (hdr->lct / 2);
266 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
272 buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
273 for (i = 0; i < (hdr->lct / 2); i++)
274 buf[idx++] = hdr->rad[i];
275 buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
276 (hdr->msg_len & 0x3f);
277 buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
279 crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
280 buf[idx - 1] |= (crc4 & 0xf);
285 static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
286 u8 *buf, int buflen, u8 *hdrlen)
295 len += ((buf[0] & 0xf0) >> 4) / 2;
298 crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
300 if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
301 DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
305 hdr->lct = (buf[0] & 0xf0) >> 4;
306 hdr->lcr = (buf[0] & 0xf);
308 for (i = 0; i < (hdr->lct / 2); i++)
309 hdr->rad[i] = buf[idx++];
310 hdr->broadcast = (buf[idx] >> 7) & 0x1;
311 hdr->path_msg = (buf[idx] >> 6) & 0x1;
312 hdr->msg_len = buf[idx] & 0x3f;
314 hdr->somt = (buf[idx] >> 7) & 0x1;
315 hdr->eomt = (buf[idx] >> 6) & 0x1;
316 hdr->seqno = (buf[idx] >> 4) & 0x1;
323 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
324 struct drm_dp_sideband_msg_tx *raw)
329 buf[idx++] = req->req_type & 0x7f;
331 switch (req->req_type) {
332 case DP_ENUM_PATH_RESOURCES:
333 case DP_POWER_DOWN_PHY:
334 case DP_POWER_UP_PHY:
335 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
338 case DP_ALLOCATE_PAYLOAD:
339 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
340 (req->u.allocate_payload.number_sdp_streams & 0xf);
342 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
344 buf[idx] = (req->u.allocate_payload.pbn >> 8);
346 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
348 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
349 buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
350 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
353 if (req->u.allocate_payload.number_sdp_streams & 1) {
354 i = req->u.allocate_payload.number_sdp_streams - 1;
355 buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
359 case DP_QUERY_PAYLOAD:
360 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
362 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
365 case DP_REMOTE_DPCD_READ:
366 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
367 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
369 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
371 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
373 buf[idx] = (req->u.dpcd_read.num_bytes);
377 case DP_REMOTE_DPCD_WRITE:
378 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
379 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
381 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
383 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
385 buf[idx] = (req->u.dpcd_write.num_bytes);
387 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
388 idx += req->u.dpcd_write.num_bytes;
390 case DP_REMOTE_I2C_READ:
391 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
392 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
394 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
395 buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
397 buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
399 memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
400 idx += req->u.i2c_read.transactions[i].num_bytes;
402 buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
403 buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
406 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
408 buf[idx] = (req->u.i2c_read.num_bytes_read);
412 case DP_REMOTE_I2C_WRITE:
413 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
415 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
417 buf[idx] = (req->u.i2c_write.num_bytes);
419 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
420 idx += req->u.i2c_write.num_bytes;
425 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
427 /* Decode a sideband request we've encoded, mainly used for debugging */
429 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
430 struct drm_dp_sideband_msg_req_body *req)
432 const u8 *buf = raw->msg;
435 req->req_type = buf[idx++] & 0x7f;
436 switch (req->req_type) {
437 case DP_ENUM_PATH_RESOURCES:
438 case DP_POWER_DOWN_PHY:
439 case DP_POWER_UP_PHY:
440 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
442 case DP_ALLOCATE_PAYLOAD:
444 struct drm_dp_allocate_payload *a =
445 &req->u.allocate_payload;
447 a->number_sdp_streams = buf[idx] & 0xf;
448 a->port_number = (buf[idx] >> 4) & 0xf;
450 WARN_ON(buf[++idx] & 0x80);
451 a->vcpi = buf[idx] & 0x7f;
453 a->pbn = buf[++idx] << 8;
454 a->pbn |= buf[++idx];
457 for (i = 0; i < a->number_sdp_streams; i++) {
458 a->sdp_stream_sink[i] =
459 (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
463 case DP_QUERY_PAYLOAD:
464 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
465 WARN_ON(buf[++idx] & 0x80);
466 req->u.query_payload.vcpi = buf[idx] & 0x7f;
468 case DP_REMOTE_DPCD_READ:
470 struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
472 r->port_number = (buf[idx] >> 4) & 0xf;
474 r->dpcd_address = (buf[idx] << 16) & 0xf0000;
475 r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
476 r->dpcd_address |= buf[++idx] & 0xff;
478 r->num_bytes = buf[++idx];
481 case DP_REMOTE_DPCD_WRITE:
483 struct drm_dp_remote_dpcd_write *w =
486 w->port_number = (buf[idx] >> 4) & 0xf;
488 w->dpcd_address = (buf[idx] << 16) & 0xf0000;
489 w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
490 w->dpcd_address |= buf[++idx] & 0xff;
492 w->num_bytes = buf[++idx];
494 w->bytes = kmemdup(&buf[++idx], w->num_bytes,
500 case DP_REMOTE_I2C_READ:
502 struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
503 struct drm_dp_remote_i2c_read_tx *tx;
506 r->num_transactions = buf[idx] & 0x3;
507 r->port_number = (buf[idx] >> 4) & 0xf;
508 for (i = 0; i < r->num_transactions; i++) {
509 tx = &r->transactions[i];
511 tx->i2c_dev_id = buf[++idx] & 0x7f;
512 tx->num_bytes = buf[++idx];
513 tx->bytes = kmemdup(&buf[++idx],
520 idx += tx->num_bytes;
521 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
522 tx->i2c_transaction_delay = buf[idx] & 0xf;
526 for (i = 0; i < r->num_transactions; i++) {
527 tx = &r->transactions[i];
533 r->read_i2c_device_id = buf[++idx] & 0x7f;
534 r->num_bytes_read = buf[++idx];
537 case DP_REMOTE_I2C_WRITE:
539 struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
541 w->port_number = (buf[idx] >> 4) & 0xf;
542 w->write_i2c_device_id = buf[++idx] & 0x7f;
543 w->num_bytes = buf[++idx];
544 w->bytes = kmemdup(&buf[++idx], w->num_bytes,
554 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
557 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
558 int indent, struct drm_printer *printer)
562 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
563 if (req->req_type == DP_LINK_ADDRESS) {
564 /* No contents to print */
565 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
569 P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
572 switch (req->req_type) {
573 case DP_ENUM_PATH_RESOURCES:
574 case DP_POWER_DOWN_PHY:
575 case DP_POWER_UP_PHY:
576 P("port=%d\n", req->u.port_num.port_number);
578 case DP_ALLOCATE_PAYLOAD:
579 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
580 req->u.allocate_payload.port_number,
581 req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
582 req->u.allocate_payload.number_sdp_streams,
583 req->u.allocate_payload.number_sdp_streams,
584 req->u.allocate_payload.sdp_stream_sink);
586 case DP_QUERY_PAYLOAD:
587 P("port=%d vcpi=%d\n",
588 req->u.query_payload.port_number,
589 req->u.query_payload.vcpi);
591 case DP_REMOTE_DPCD_READ:
592 P("port=%d dpcd_addr=%05x len=%d\n",
593 req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
594 req->u.dpcd_read.num_bytes);
596 case DP_REMOTE_DPCD_WRITE:
597 P("port=%d addr=%05x len=%d: %*ph\n",
598 req->u.dpcd_write.port_number,
599 req->u.dpcd_write.dpcd_address,
600 req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
601 req->u.dpcd_write.bytes);
603 case DP_REMOTE_I2C_READ:
604 P("port=%d num_tx=%d id=%d size=%d:\n",
605 req->u.i2c_read.port_number,
606 req->u.i2c_read.num_transactions,
607 req->u.i2c_read.read_i2c_device_id,
608 req->u.i2c_read.num_bytes_read);
611 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
612 const struct drm_dp_remote_i2c_read_tx *rtx =
613 &req->u.i2c_read.transactions[i];
615 P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
616 i, rtx->i2c_dev_id, rtx->num_bytes,
617 rtx->no_stop_bit, rtx->i2c_transaction_delay,
618 rtx->num_bytes, rtx->bytes);
621 case DP_REMOTE_I2C_WRITE:
622 P("port=%d id=%d size=%d: %*ph\n",
623 req->u.i2c_write.port_number,
624 req->u.i2c_write.write_i2c_device_id,
625 req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
626 req->u.i2c_write.bytes);
634 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
637 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
638 const struct drm_dp_sideband_msg_tx *txmsg)
640 struct drm_dp_sideband_msg_req_body req;
645 drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
647 drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
648 txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
649 drm_dp_mst_sideband_tx_state_str(txmsg->state),
650 txmsg->path_msg, buf);
652 ret = drm_dp_decode_sideband_req(txmsg, &req);
654 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
657 drm_dp_dump_sideband_msg_req_body(&req, 1, p);
659 switch (req.req_type) {
660 case DP_REMOTE_DPCD_WRITE:
661 kfree(req.u.dpcd_write.bytes);
663 case DP_REMOTE_I2C_READ:
664 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
665 kfree(req.u.i2c_read.transactions[i].bytes);
667 case DP_REMOTE_I2C_WRITE:
668 kfree(req.u.i2c_write.bytes);
673 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
676 crc4 = drm_dp_msg_data_crc4(msg, len);
680 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
681 struct drm_dp_sideband_msg_tx *raw)
686 buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
691 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
692 struct drm_dp_sideband_msg_hdr *hdr,
696 * ignore out-of-order messages or messages that are part of a
699 if (!hdr->somt && !msg->have_somt)
702 /* get length contained in this portion */
703 msg->curchunk_idx = 0;
704 msg->curchunk_len = hdr->msg_len;
705 msg->curchunk_hdrlen = hdrlen;
707 /* we have already gotten an somt - don't bother parsing */
708 if (hdr->somt && msg->have_somt)
712 memcpy(&msg->initial_hdr, hdr,
713 sizeof(struct drm_dp_sideband_msg_hdr));
714 msg->have_somt = true;
717 msg->have_eomt = true;
722 /* this adds a chunk of msg to the builder to get the final msg */
723 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
724 u8 *replybuf, u8 replybuflen)
728 memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
729 msg->curchunk_idx += replybuflen;
731 if (msg->curchunk_idx >= msg->curchunk_len) {
733 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
734 if (crc4 != msg->chunk[msg->curchunk_len - 1])
735 print_hex_dump(KERN_DEBUG, "wrong crc",
736 DUMP_PREFIX_NONE, 16, 1,
737 msg->chunk, msg->curchunk_len, false);
738 /* copy chunk into bigger msg */
739 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
740 msg->curlen += msg->curchunk_len - 1;
745 static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
746 struct drm_dp_sideband_msg_reply_body *repmsg)
750 memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
752 repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
754 if (idx > raw->curlen)
756 for (i = 0; i < repmsg->u.link_addr.nports; i++) {
757 if (raw->msg[idx] & 0x80)
758 repmsg->u.link_addr.ports[i].input_port = 1;
760 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
761 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
764 if (idx > raw->curlen)
766 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
767 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
768 if (repmsg->u.link_addr.ports[i].input_port == 0)
769 repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
771 if (idx > raw->curlen)
773 if (repmsg->u.link_addr.ports[i].input_port == 0) {
774 repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
776 if (idx > raw->curlen)
778 memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
780 if (idx > raw->curlen)
782 repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
783 repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
787 if (idx > raw->curlen)
793 DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
797 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
798 struct drm_dp_sideband_msg_reply_body *repmsg)
801 repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
803 if (idx > raw->curlen)
805 repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
807 if (idx > raw->curlen)
810 memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
813 DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
817 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
818 struct drm_dp_sideband_msg_reply_body *repmsg)
821 repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
823 if (idx > raw->curlen)
827 DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
831 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
832 struct drm_dp_sideband_msg_reply_body *repmsg)
836 repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
838 if (idx > raw->curlen)
840 repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
843 memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
846 DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
850 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
851 struct drm_dp_sideband_msg_reply_body *repmsg)
854 repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
855 repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
857 if (idx > raw->curlen)
859 repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
861 if (idx > raw->curlen)
863 repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
865 if (idx > raw->curlen)
869 DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
873 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
874 struct drm_dp_sideband_msg_reply_body *repmsg)
877 repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
879 if (idx > raw->curlen)
881 repmsg->u.allocate_payload.vcpi = raw->msg[idx];
883 if (idx > raw->curlen)
885 repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
887 if (idx > raw->curlen)
891 DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
895 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
896 struct drm_dp_sideband_msg_reply_body *repmsg)
899 repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
901 if (idx > raw->curlen)
903 repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
905 if (idx > raw->curlen)
909 DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
913 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
914 struct drm_dp_sideband_msg_reply_body *repmsg)
918 repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
920 if (idx > raw->curlen) {
921 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
928 static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
929 struct drm_dp_sideband_msg_reply_body *msg)
931 memset(msg, 0, sizeof(*msg));
932 msg->reply_type = (raw->msg[0] & 0x80) >> 7;
933 msg->req_type = (raw->msg[0] & 0x7f);
935 if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
936 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
937 msg->u.nak.reason = raw->msg[17];
938 msg->u.nak.nak_data = raw->msg[18];
942 switch (msg->req_type) {
943 case DP_LINK_ADDRESS:
944 return drm_dp_sideband_parse_link_address(raw, msg);
945 case DP_QUERY_PAYLOAD:
946 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
947 case DP_REMOTE_DPCD_READ:
948 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
949 case DP_REMOTE_DPCD_WRITE:
950 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
951 case DP_REMOTE_I2C_READ:
952 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
953 case DP_ENUM_PATH_RESOURCES:
954 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
955 case DP_ALLOCATE_PAYLOAD:
956 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
957 case DP_POWER_DOWN_PHY:
958 case DP_POWER_UP_PHY:
959 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
960 case DP_CLEAR_PAYLOAD_ID_TABLE:
961 return true; /* since there's nothing to parse */
963 DRM_ERROR("Got unknown reply 0x%02x (%s)\n", msg->req_type,
964 drm_dp_mst_req_type_str(msg->req_type));
969 static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
970 struct drm_dp_sideband_msg_req_body *msg)
974 msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
976 if (idx > raw->curlen)
979 memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
981 if (idx > raw->curlen)
984 msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
985 msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
986 msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
987 msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
988 msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
992 DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
996 static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
997 struct drm_dp_sideband_msg_req_body *msg)
1001 msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1003 if (idx > raw->curlen)
1006 memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1008 if (idx > raw->curlen)
1011 msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1015 DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
1019 static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
1020 struct drm_dp_sideband_msg_req_body *msg)
1022 memset(msg, 0, sizeof(*msg));
1023 msg->req_type = (raw->msg[0] & 0x7f);
1025 switch (msg->req_type) {
1026 case DP_CONNECTION_STATUS_NOTIFY:
1027 return drm_dp_sideband_parse_connection_status_notify(raw, msg);
1028 case DP_RESOURCE_STATUS_NOTIFY:
1029 return drm_dp_sideband_parse_resource_status_notify(raw, msg);
1031 DRM_ERROR("Got unknown request 0x%02x (%s)\n", msg->req_type,
1032 drm_dp_mst_req_type_str(msg->req_type));
1037 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1038 u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1040 struct drm_dp_sideband_msg_req_body req;
1042 req.req_type = DP_REMOTE_DPCD_WRITE;
1043 req.u.dpcd_write.port_number = port_num;
1044 req.u.dpcd_write.dpcd_address = offset;
1045 req.u.dpcd_write.num_bytes = num_bytes;
1046 req.u.dpcd_write.bytes = bytes;
1047 drm_dp_encode_sideband_req(&req, msg);
1050 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1052 struct drm_dp_sideband_msg_req_body req;
1054 req.req_type = DP_LINK_ADDRESS;
1055 drm_dp_encode_sideband_req(&req, msg);
1058 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1060 struct drm_dp_sideband_msg_req_body req;
1062 req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1063 drm_dp_encode_sideband_req(&req, msg);
1066 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1069 struct drm_dp_sideband_msg_req_body req;
1071 req.req_type = DP_ENUM_PATH_RESOURCES;
1072 req.u.port_num.port_number = port_num;
1073 drm_dp_encode_sideband_req(&req, msg);
1074 msg->path_msg = true;
1078 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1080 u8 vcpi, uint16_t pbn,
1081 u8 number_sdp_streams,
1082 u8 *sdp_stream_sink)
1084 struct drm_dp_sideband_msg_req_body req;
1085 memset(&req, 0, sizeof(req));
1086 req.req_type = DP_ALLOCATE_PAYLOAD;
1087 req.u.allocate_payload.port_number = port_num;
1088 req.u.allocate_payload.vcpi = vcpi;
1089 req.u.allocate_payload.pbn = pbn;
1090 req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1091 memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1092 number_sdp_streams);
1093 drm_dp_encode_sideband_req(&req, msg);
1094 msg->path_msg = true;
1097 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1098 int port_num, bool power_up)
1100 struct drm_dp_sideband_msg_req_body req;
1103 req.req_type = DP_POWER_UP_PHY;
1105 req.req_type = DP_POWER_DOWN_PHY;
1107 req.u.port_num.port_number = port_num;
1108 drm_dp_encode_sideband_req(&req, msg);
1109 msg->path_msg = true;
1112 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1113 struct drm_dp_vcpi *vcpi)
1117 mutex_lock(&mgr->payload_lock);
1118 ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1119 if (ret > mgr->max_payloads) {
1121 DRM_DEBUG_KMS("out of payload ids %d\n", ret);
1125 vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1126 if (vcpi_ret > mgr->max_payloads) {
1128 DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
1132 set_bit(ret, &mgr->payload_mask);
1133 set_bit(vcpi_ret, &mgr->vcpi_mask);
1134 vcpi->vcpi = vcpi_ret + 1;
1135 mgr->proposed_vcpis[ret - 1] = vcpi;
1137 mutex_unlock(&mgr->payload_lock);
1141 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1148 mutex_lock(&mgr->payload_lock);
1149 DRM_DEBUG_KMS("putting payload %d\n", vcpi);
1150 clear_bit(vcpi - 1, &mgr->vcpi_mask);
1152 for (i = 0; i < mgr->max_payloads; i++) {
1153 if (mgr->proposed_vcpis[i] &&
1154 mgr->proposed_vcpis[i]->vcpi == vcpi) {
1155 mgr->proposed_vcpis[i] = NULL;
1156 clear_bit(i + 1, &mgr->payload_mask);
1159 mutex_unlock(&mgr->payload_lock);
1162 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1163 struct drm_dp_sideband_msg_tx *txmsg)
1168 * All updates to txmsg->state are protected by mgr->qlock, and the two
1169 * cases we check here are terminal states. For those the barriers
1170 * provided by the wake_up/wait_event pair are enough.
1172 state = READ_ONCE(txmsg->state);
1173 return (state == DRM_DP_SIDEBAND_TX_RX ||
1174 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1177 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1178 struct drm_dp_sideband_msg_tx *txmsg)
1180 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1181 unsigned long wait_timeout = msecs_to_jiffies(4000);
1182 unsigned long wait_expires = jiffies + wait_timeout;
1187 * If the driver provides a way for this, change to
1188 * poll-waiting for the MST reply interrupt if we didn't receive
1189 * it for 50 msec. This would cater for cases where the HPD
1190 * pulse signal got lost somewhere, even though the sink raised
1191 * the corresponding MST interrupt correctly. One example is the
1192 * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1193 * filters out short pulses with a duration less than ~540 usec.
1195 * The poll period is 50 msec to avoid missing an interrupt
1196 * after the sink has cleared it (after a 110msec timeout
1197 * since it raised the interrupt).
1199 ret = wait_event_timeout(mgr->tx_waitq,
1200 check_txmsg_state(mgr, txmsg),
1201 mgr->cbs->poll_hpd_irq ?
1202 msecs_to_jiffies(50) :
1205 if (ret || !mgr->cbs->poll_hpd_irq ||
1206 time_after(jiffies, wait_expires))
1209 mgr->cbs->poll_hpd_irq(mgr);
1212 mutex_lock(&mgr->qlock);
1214 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1219 DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
1221 /* dump some state */
1225 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1226 txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1227 txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1228 list_del(&txmsg->next);
1231 if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1232 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1234 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1236 mutex_unlock(&mgr->qlock);
1238 drm_dp_mst_kick_tx(mgr);
1242 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1244 struct drm_dp_mst_branch *mstb;
1246 mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1252 memcpy(mstb->rad, rad, lct / 2);
1253 INIT_LIST_HEAD(&mstb->ports);
1254 kref_init(&mstb->topology_kref);
1255 kref_init(&mstb->malloc_kref);
1259 static void drm_dp_free_mst_branch_device(struct kref *kref)
1261 struct drm_dp_mst_branch *mstb =
1262 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1264 if (mstb->port_parent)
1265 drm_dp_mst_put_port_malloc(mstb->port_parent);
1271 * DOC: Branch device and port refcounting
1273 * Topology refcount overview
1274 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1276 * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1277 * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1278 * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1280 * Topology refcounts are not exposed to drivers, and are handled internally
1281 * by the DP MST helpers. The helpers use them in order to prevent the
1282 * in-memory topology state from being changed in the middle of critical
1283 * operations like changing the internal state of payload allocations. This
1284 * means each branch and port will be considered to be connected to the rest
1285 * of the topology until its topology refcount reaches zero. Additionally,
1286 * for ports this means that their associated &struct drm_connector will stay
1287 * registered with userspace until the port's refcount reaches 0.
1289 * Malloc refcount overview
1290 * ~~~~~~~~~~~~~~~~~~~~~~~~
1292 * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1293 * drm_dp_mst_branch allocated even after all of its topology references have
1294 * been dropped, so that the driver or MST helpers can safely access each
1295 * branch's last known state before it was disconnected from the topology.
1296 * When the malloc refcount of a port or branch reaches 0, the memory
1297 * allocation containing the &struct drm_dp_mst_branch or &struct
1298 * drm_dp_mst_port respectively will be freed.
1300 * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1301 * to drivers. As of writing this documentation, there are no drivers that
1302 * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1303 * helpers. Exposing this API to drivers in a race-free manner would take more
1304 * tweaking of the refcounting scheme, however patches are welcome provided
1305 * there is a legitimate driver usecase for this.
1307 * Refcount relationships in a topology
1308 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1310 * Let's take a look at why the relationship between topology and malloc
1311 * refcounts is designed the way it is.
1313 * .. kernel-figure:: dp-mst/topology-figure-1.dot
1315 * An example of topology and malloc refs in a DP MST topology with two
1316 * active payloads. Topology refcount increments are indicated by solid
1317 * lines, and malloc refcount increments are indicated by dashed lines.
1318 * Each starts from the branch which incremented the refcount, and ends at
1319 * the branch to which the refcount belongs to, i.e. the arrow points the
1320 * same way as the C pointers used to reference a structure.
1322 * As you can see in the above figure, every branch increments the topology
1323 * refcount of its children, and increments the malloc refcount of its
1324 * parent. Additionally, every payload increments the malloc refcount of its
1325 * assigned port by 1.
1327 * So, what would happen if MSTB #3 from the above figure was unplugged from
1328 * the system, but the driver hadn't yet removed payload #2 from port #3? The
1329 * topology would start to look like the figure below.
1331 * .. kernel-figure:: dp-mst/topology-figure-2.dot
1333 * Ports and branch devices which have been released from memory are
1334 * colored grey, and references which have been removed are colored red.
1336 * Whenever a port or branch device's topology refcount reaches zero, it will
1337 * decrement the topology refcounts of all its children, the malloc refcount
1338 * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1339 * #4, this means they both have been disconnected from the topology and freed
1340 * from memory. But, because payload #2 is still holding a reference to port
1341 * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1342 * is still accessible from memory. This also means port #3 has not yet
1343 * decremented the malloc refcount of MSTB #3, so its &struct
1344 * drm_dp_mst_branch will also stay allocated in memory until port #3's
1345 * malloc refcount reaches 0.
1347 * This relationship is necessary because in order to release payload #2, we
1348 * need to be able to figure out the last relative of port #3 that's still
1349 * connected to the topology. In this case, we would travel up the topology as
1352 * .. kernel-figure:: dp-mst/topology-figure-3.dot
1354 * And finally, remove payload #2 by communicating with port #2 through
1355 * sideband transactions.
1359 * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1361 * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1363 * Increments &drm_dp_mst_branch.malloc_kref. When
1364 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1365 * will be released and @mstb may no longer be used.
1367 * See also: drm_dp_mst_put_mstb_malloc()
1370 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1372 kref_get(&mstb->malloc_kref);
1373 DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1377 * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1379 * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1381 * Decrements &drm_dp_mst_branch.malloc_kref. When
1382 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1383 * will be released and @mstb may no longer be used.
1385 * See also: drm_dp_mst_get_mstb_malloc()
1388 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1390 DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1391 kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1394 static void drm_dp_free_mst_port(struct kref *kref)
1396 struct drm_dp_mst_port *port =
1397 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1399 drm_dp_mst_put_mstb_malloc(port->parent);
1404 * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1405 * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1407 * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1408 * reaches 0, the memory allocation for @port will be released and @port may
1409 * no longer be used.
1411 * Because @port could potentially be freed at any time by the DP MST helpers
1412 * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1413 * function, drivers that which to make use of &struct drm_dp_mst_port should
1414 * ensure that they grab at least one main malloc reference to their MST ports
1415 * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1416 * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1418 * See also: drm_dp_mst_put_port_malloc()
1421 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1423 kref_get(&port->malloc_kref);
1424 DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref));
1426 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1429 * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1430 * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1432 * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1433 * reaches 0, the memory allocation for @port will be released and @port may
1434 * no longer be used.
1436 * See also: drm_dp_mst_get_port_malloc()
1439 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1441 DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1442 kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1444 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1446 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1448 #define STACK_DEPTH 8
1450 static noinline void
1451 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1452 struct drm_dp_mst_topology_ref_history *history,
1453 enum drm_dp_mst_topology_ref_type type)
1455 struct drm_dp_mst_topology_ref_entry *entry = NULL;
1456 depot_stack_handle_t backtrace;
1457 ulong stack_entries[STACK_DEPTH];
1461 n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1462 backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1466 /* Try to find an existing entry for this backtrace */
1467 for (i = 0; i < history->len; i++) {
1468 if (history->entries[i].backtrace == backtrace) {
1469 entry = &history->entries[i];
1474 /* Otherwise add one */
1476 struct drm_dp_mst_topology_ref_entry *new;
1477 int new_len = history->len + 1;
1479 new = krealloc(history->entries, sizeof(*new) * new_len,
1484 entry = &new[history->len];
1485 history->len = new_len;
1486 history->entries = new;
1488 entry->backtrace = backtrace;
1493 entry->ts_nsec = ktime_get_ns();
1497 topology_ref_history_cmp(const void *a, const void *b)
1499 const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1501 if (entry_a->ts_nsec > entry_b->ts_nsec)
1503 else if (entry_a->ts_nsec < entry_b->ts_nsec)
1509 static inline const char *
1510 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1512 if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1519 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1520 void *ptr, const char *type_str)
1522 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1523 char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1532 /* First, sort the list so that it goes from oldest to newest
1535 sort(history->entries, history->len, sizeof(*history->entries),
1536 topology_ref_history_cmp, NULL);
1538 drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1541 for (i = 0; i < history->len; i++) {
1542 const struct drm_dp_mst_topology_ref_entry *entry =
1543 &history->entries[i];
1546 u64 ts_nsec = entry->ts_nsec;
1547 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1549 nr_entries = stack_depot_fetch(entry->backtrace, &entries);
1550 stack_trace_snprint(buf, PAGE_SIZE, entries, nr_entries, 4);
1552 drm_printf(&p, " %d %ss (last at %5llu.%06u):\n%s",
1554 topology_ref_type_to_str(entry->type),
1555 ts_nsec, rem_nsec / 1000, buf);
1558 /* Now free the history, since this is the only time we expose it */
1559 kfree(history->entries);
1564 static __always_inline void
1565 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1567 __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1571 static __always_inline void
1572 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1574 __dump_topology_ref_history(&port->topology_ref_history, port,
1578 static __always_inline void
1579 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1580 enum drm_dp_mst_topology_ref_type type)
1582 __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1585 static __always_inline void
1586 save_port_topology_ref(struct drm_dp_mst_port *port,
1587 enum drm_dp_mst_topology_ref_type type)
1589 __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1593 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1595 mutex_lock(&mgr->topology_ref_history_lock);
1599 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1601 mutex_unlock(&mgr->topology_ref_history_lock);
1605 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1607 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1609 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1611 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1612 #define save_mstb_topology_ref(mstb, type)
1613 #define save_port_topology_ref(port, type)
1616 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1618 struct drm_dp_mst_branch *mstb =
1619 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1620 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1622 drm_dp_mst_dump_mstb_topology_history(mstb);
1624 INIT_LIST_HEAD(&mstb->destroy_next);
1627 * This can get called under mgr->mutex, so we need to perform the
1628 * actual destruction of the mstb in another worker
1630 mutex_lock(&mgr->delayed_destroy_lock);
1631 list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1632 mutex_unlock(&mgr->delayed_destroy_lock);
1633 queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1637 * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1638 * branch device unless it's zero
1639 * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1641 * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1642 * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1643 * reached 0). Holding a topology reference implies that a malloc reference
1644 * will be held to @mstb as long as the user holds the topology reference.
1646 * Care should be taken to ensure that the user has at least one malloc
1647 * reference to @mstb. If you already have a topology reference to @mstb, you
1648 * should use drm_dp_mst_topology_get_mstb() instead.
1651 * drm_dp_mst_topology_get_mstb()
1652 * drm_dp_mst_topology_put_mstb()
1655 * * 1: A topology reference was grabbed successfully
1656 * * 0: @port is no longer in the topology, no reference was grabbed
1658 static int __must_check
1659 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1663 topology_ref_history_lock(mstb->mgr);
1664 ret = kref_get_unless_zero(&mstb->topology_kref);
1666 DRM_DEBUG("mstb %p (%d)\n",
1667 mstb, kref_read(&mstb->topology_kref));
1668 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1671 topology_ref_history_unlock(mstb->mgr);
1677 * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1679 * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1681 * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1682 * not it's already reached 0. This is only valid to use in scenarios where
1683 * you are already guaranteed to have at least one active topology reference
1684 * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1687 * drm_dp_mst_topology_try_get_mstb()
1688 * drm_dp_mst_topology_put_mstb()
1690 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1692 topology_ref_history_lock(mstb->mgr);
1694 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1695 WARN_ON(kref_read(&mstb->topology_kref) == 0);
1696 kref_get(&mstb->topology_kref);
1697 DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1699 topology_ref_history_unlock(mstb->mgr);
1703 * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1705 * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1707 * Releases a topology reference from @mstb by decrementing
1708 * &drm_dp_mst_branch.topology_kref.
1711 * drm_dp_mst_topology_try_get_mstb()
1712 * drm_dp_mst_topology_get_mstb()
1715 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1717 topology_ref_history_lock(mstb->mgr);
1719 DRM_DEBUG("mstb %p (%d)\n",
1720 mstb, kref_read(&mstb->topology_kref) - 1);
1721 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1723 topology_ref_history_unlock(mstb->mgr);
1724 kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1727 static void drm_dp_destroy_port(struct kref *kref)
1729 struct drm_dp_mst_port *port =
1730 container_of(kref, struct drm_dp_mst_port, topology_kref);
1731 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1733 drm_dp_mst_dump_port_topology_history(port);
1735 /* There's nothing that needs locking to destroy an input port yet */
1737 drm_dp_mst_put_port_malloc(port);
1741 kfree(port->cached_edid);
1744 * we can't destroy the connector here, as we might be holding the
1745 * mode_config.mutex from an EDID retrieval
1747 mutex_lock(&mgr->delayed_destroy_lock);
1748 list_add(&port->next, &mgr->destroy_port_list);
1749 mutex_unlock(&mgr->delayed_destroy_lock);
1750 queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1754 * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1755 * port unless it's zero
1756 * @port: &struct drm_dp_mst_port to increment the topology refcount of
1758 * Attempts to grab a topology reference to @port, if it hasn't yet been
1759 * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1760 * 0). Holding a topology reference implies that a malloc reference will be
1761 * held to @port as long as the user holds the topology reference.
1763 * Care should be taken to ensure that the user has at least one malloc
1764 * reference to @port. If you already have a topology reference to @port, you
1765 * should use drm_dp_mst_topology_get_port() instead.
1768 * drm_dp_mst_topology_get_port()
1769 * drm_dp_mst_topology_put_port()
1772 * * 1: A topology reference was grabbed successfully
1773 * * 0: @port is no longer in the topology, no reference was grabbed
1775 static int __must_check
1776 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1780 topology_ref_history_lock(port->mgr);
1781 ret = kref_get_unless_zero(&port->topology_kref);
1783 DRM_DEBUG("port %p (%d)\n",
1784 port, kref_read(&port->topology_kref));
1785 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1788 topology_ref_history_unlock(port->mgr);
1793 * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1794 * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1796 * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1797 * not it's already reached 0. This is only valid to use in scenarios where
1798 * you are already guaranteed to have at least one active topology reference
1799 * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1802 * drm_dp_mst_topology_try_get_port()
1803 * drm_dp_mst_topology_put_port()
1805 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1807 topology_ref_history_lock(port->mgr);
1809 WARN_ON(kref_read(&port->topology_kref) == 0);
1810 kref_get(&port->topology_kref);
1811 DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->topology_kref));
1812 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1814 topology_ref_history_unlock(port->mgr);
1818 * drm_dp_mst_topology_put_port() - release a topology reference to a port
1819 * @port: The &struct drm_dp_mst_port to release the topology reference from
1821 * Releases a topology reference from @port by decrementing
1822 * &drm_dp_mst_port.topology_kref.
1825 * drm_dp_mst_topology_try_get_port()
1826 * drm_dp_mst_topology_get_port()
1828 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1830 topology_ref_history_lock(port->mgr);
1832 DRM_DEBUG("port %p (%d)\n",
1833 port, kref_read(&port->topology_kref) - 1);
1834 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1836 topology_ref_history_unlock(port->mgr);
1837 kref_put(&port->topology_kref, drm_dp_destroy_port);
1840 static struct drm_dp_mst_branch *
1841 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1842 struct drm_dp_mst_branch *to_find)
1844 struct drm_dp_mst_port *port;
1845 struct drm_dp_mst_branch *rmstb;
1847 if (to_find == mstb)
1850 list_for_each_entry(port, &mstb->ports, next) {
1852 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1853 port->mstb, to_find);
1861 static struct drm_dp_mst_branch *
1862 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1863 struct drm_dp_mst_branch *mstb)
1865 struct drm_dp_mst_branch *rmstb = NULL;
1867 mutex_lock(&mgr->lock);
1868 if (mgr->mst_primary) {
1869 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1870 mgr->mst_primary, mstb);
1872 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1875 mutex_unlock(&mgr->lock);
1879 static struct drm_dp_mst_port *
1880 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1881 struct drm_dp_mst_port *to_find)
1883 struct drm_dp_mst_port *port, *mport;
1885 list_for_each_entry(port, &mstb->ports, next) {
1886 if (port == to_find)
1890 mport = drm_dp_mst_topology_get_port_validated_locked(
1891 port->mstb, to_find);
1899 static struct drm_dp_mst_port *
1900 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1901 struct drm_dp_mst_port *port)
1903 struct drm_dp_mst_port *rport = NULL;
1905 mutex_lock(&mgr->lock);
1906 if (mgr->mst_primary) {
1907 rport = drm_dp_mst_topology_get_port_validated_locked(
1908 mgr->mst_primary, port);
1910 if (rport && !drm_dp_mst_topology_try_get_port(rport))
1913 mutex_unlock(&mgr->lock);
1917 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
1919 struct drm_dp_mst_port *port;
1922 list_for_each_entry(port, &mstb->ports, next) {
1923 if (port->port_num == port_num) {
1924 ret = drm_dp_mst_topology_try_get_port(port);
1925 return ret ? port : NULL;
1933 * calculate a new RAD for this MST branch device
1934 * if parent has an LCT of 2 then it has 1 nibble of RAD,
1935 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
1937 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
1940 int parent_lct = port->parent->lct;
1942 int idx = (parent_lct - 1) / 2;
1943 if (parent_lct > 1) {
1944 memcpy(rad, port->parent->rad, idx + 1);
1945 shift = (parent_lct % 2) ? 4 : 0;
1949 rad[idx] |= port->port_num << shift;
1950 return parent_lct + 1;
1953 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
1956 case DP_PEER_DEVICE_DP_LEGACY_CONV:
1957 case DP_PEER_DEVICE_SST_SINK:
1959 case DP_PEER_DEVICE_MST_BRANCHING:
1960 /* For sst branch device */
1970 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
1973 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1974 struct drm_dp_mst_branch *mstb;
1978 if (port->pdt == new_pdt && port->mcs == new_mcs)
1981 /* Teardown the old pdt, if there is one */
1982 if (port->pdt != DP_PEER_DEVICE_NONE) {
1983 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
1985 * If the new PDT would also have an i2c bus,
1986 * don't bother with reregistering it
1988 if (new_pdt != DP_PEER_DEVICE_NONE &&
1989 drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
1990 port->pdt = new_pdt;
1991 port->mcs = new_mcs;
1995 /* remove i2c over sideband */
1996 drm_dp_mst_unregister_i2c_bus(port);
1998 mutex_lock(&mgr->lock);
1999 drm_dp_mst_topology_put_mstb(port->mstb);
2001 mutex_unlock(&mgr->lock);
2005 port->pdt = new_pdt;
2006 port->mcs = new_mcs;
2008 if (port->pdt != DP_PEER_DEVICE_NONE) {
2009 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2010 /* add i2c over sideband */
2011 ret = drm_dp_mst_register_i2c_bus(port);
2013 lct = drm_dp_calculate_rad(port, rad);
2014 mstb = drm_dp_add_mst_branch_device(lct, rad);
2017 DRM_ERROR("Failed to create MSTB for port %p",
2022 mutex_lock(&mgr->lock);
2024 mstb->mgr = port->mgr;
2025 mstb->port_parent = port;
2028 * Make sure this port's memory allocation stays
2029 * around until its child MSTB releases it
2031 drm_dp_mst_get_port_malloc(port);
2032 mutex_unlock(&mgr->lock);
2034 /* And make sure we send a link address for this */
2041 port->pdt = DP_PEER_DEVICE_NONE;
2046 * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2047 * @aux: Fake sideband AUX CH
2048 * @offset: address of the (first) register to read
2049 * @buffer: buffer to store the register values
2050 * @size: number of bytes in @buffer
2052 * Performs the same functionality for remote devices via
2053 * sideband messaging as drm_dp_dpcd_read() does for local
2054 * devices via actual AUX CH.
2056 * Return: Number of bytes read, or negative error code on failure.
2058 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2059 unsigned int offset, void *buffer, size_t size)
2061 struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2064 return drm_dp_send_dpcd_read(port->mgr, port,
2065 offset, size, buffer);
2069 * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2070 * @aux: Fake sideband AUX CH
2071 * @offset: address of the (first) register to write
2072 * @buffer: buffer containing the values to write
2073 * @size: number of bytes in @buffer
2075 * Performs the same functionality for remote devices via
2076 * sideband messaging as drm_dp_dpcd_write() does for local
2077 * devices via actual AUX CH.
2079 * Return: number of bytes written on success, negative error code on failure.
2081 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2082 unsigned int offset, void *buffer, size_t size)
2084 struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2087 return drm_dp_send_dpcd_write(port->mgr, port,
2088 offset, size, buffer);
2091 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2095 memcpy(mstb->guid, guid, 16);
2097 if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2098 if (mstb->port_parent) {
2099 ret = drm_dp_send_dpcd_write(mstb->mgr,
2101 DP_GUID, 16, mstb->guid);
2103 ret = drm_dp_dpcd_write(mstb->mgr->aux,
2104 DP_GUID, mstb->guid, 16);
2108 if (ret < 16 && ret > 0)
2111 return ret == 16 ? 0 : ret;
2114 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2117 size_t proppath_size)
2121 snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2122 for (i = 0; i < (mstb->lct - 1); i++) {
2123 int shift = (i % 2) ? 0 : 4;
2124 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2125 snprintf(temp, sizeof(temp), "-%d", port_num);
2126 strlcat(proppath, temp, proppath_size);
2128 snprintf(temp, sizeof(temp), "-%d", pnum);
2129 strlcat(proppath, temp, proppath_size);
2133 * drm_dp_mst_connector_late_register() - Late MST connector registration
2134 * @connector: The MST connector
2135 * @port: The MST port for this connector
2137 * Helper to register the remote aux device for this MST port. Drivers should
2138 * call this from their mst connector's late_register hook to enable MST aux
2141 * Return: 0 on success, negative error code on failure.
2143 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2144 struct drm_dp_mst_port *port)
2146 DRM_DEBUG_KMS("registering %s remote bus for %s\n",
2147 port->aux.name, connector->kdev->kobj.name);
2149 port->aux.dev = connector->kdev;
2150 return drm_dp_aux_register_devnode(&port->aux);
2152 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2155 * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2156 * @connector: The MST connector
2157 * @port: The MST port for this connector
2159 * Helper to unregister the remote aux device for this MST port, registered by
2160 * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2161 * connector's early_unregister hook.
2163 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2164 struct drm_dp_mst_port *port)
2166 DRM_DEBUG_KMS("unregistering %s remote bus for %s\n",
2167 port->aux.name, connector->kdev->kobj.name);
2168 drm_dp_aux_unregister_devnode(&port->aux);
2170 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2173 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2174 struct drm_dp_mst_port *port)
2176 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2180 build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2181 port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2182 if (!port->connector) {
2187 if (port->pdt != DP_PEER_DEVICE_NONE &&
2188 drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2189 port->cached_edid = drm_get_edid(port->connector,
2191 drm_connector_set_tile_property(port->connector);
2194 drm_connector_register(port->connector);
2198 DRM_ERROR("Failed to create connector for port %p: %d\n", port, ret);
2202 * Drop a topology reference, and unlink the port from the in-memory topology
2206 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2207 struct drm_dp_mst_port *port)
2209 mutex_lock(&mgr->lock);
2210 port->parent->num_ports--;
2211 list_del(&port->next);
2212 mutex_unlock(&mgr->lock);
2213 drm_dp_mst_topology_put_port(port);
2216 static struct drm_dp_mst_port *
2217 drm_dp_mst_add_port(struct drm_device *dev,
2218 struct drm_dp_mst_topology_mgr *mgr,
2219 struct drm_dp_mst_branch *mstb, u8 port_number)
2221 struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2226 kref_init(&port->topology_kref);
2227 kref_init(&port->malloc_kref);
2228 port->parent = mstb;
2229 port->port_num = port_number;
2231 port->aux.name = "DPMST";
2232 port->aux.dev = dev->dev;
2233 port->aux.is_remote = true;
2235 /* initialize the MST downstream port's AUX crc work queue */
2236 drm_dp_remote_aux_init(&port->aux);
2239 * Make sure the memory allocation for our parent branch stays
2240 * around until our own memory allocation is released
2242 drm_dp_mst_get_mstb_malloc(mstb);
2248 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2249 struct drm_device *dev,
2250 struct drm_dp_link_addr_reply_port *port_msg)
2252 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2253 struct drm_dp_mst_port *port;
2254 int old_ddps = 0, ret;
2255 u8 new_pdt = DP_PEER_DEVICE_NONE;
2257 bool created = false, send_link_addr = false, changed = false;
2259 port = drm_dp_get_port(mstb, port_msg->port_number);
2261 port = drm_dp_mst_add_port(dev, mgr, mstb,
2262 port_msg->port_number);
2267 } else if (!port->input && port_msg->input_port && port->connector) {
2268 /* Since port->connector can't be changed here, we create a
2269 * new port if input_port changes from 0 to 1
2271 drm_dp_mst_topology_unlink_port(mgr, port);
2272 drm_dp_mst_topology_put_port(port);
2273 port = drm_dp_mst_add_port(dev, mgr, mstb,
2274 port_msg->port_number);
2279 } else if (port->input && !port_msg->input_port) {
2281 } else if (port->connector) {
2282 /* We're updating a port that's exposed to userspace, so do it
2285 drm_modeset_lock(&mgr->base.lock, NULL);
2287 old_ddps = port->ddps;
2288 changed = port->ddps != port_msg->ddps ||
2290 (port->ldps != port_msg->legacy_device_plug_status ||
2291 port->dpcd_rev != port_msg->dpcd_revision ||
2292 port->mcs != port_msg->mcs ||
2293 port->pdt != port_msg->peer_device_type ||
2294 port->num_sdp_stream_sinks !=
2295 port_msg->num_sdp_stream_sinks));
2298 port->input = port_msg->input_port;
2300 new_pdt = port_msg->peer_device_type;
2301 new_mcs = port_msg->mcs;
2302 port->ddps = port_msg->ddps;
2303 port->ldps = port_msg->legacy_device_plug_status;
2304 port->dpcd_rev = port_msg->dpcd_revision;
2305 port->num_sdp_streams = port_msg->num_sdp_streams;
2306 port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2308 /* manage mstb port lists with mgr lock - take a reference
2311 mutex_lock(&mgr->lock);
2312 drm_dp_mst_topology_get_port(port);
2313 list_add(&port->next, &mstb->ports);
2315 mutex_unlock(&mgr->lock);
2319 * Reprobe PBN caps on both hotplug, and when re-probing the link
2320 * for our parent mstb
2322 if (old_ddps != port->ddps || !created) {
2323 if (port->ddps && !port->input) {
2324 ret = drm_dp_send_enum_path_resources(mgr, mstb,
2333 ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2335 send_link_addr = true;
2336 } else if (ret < 0) {
2337 DRM_ERROR("Failed to change PDT on port %p: %d\n",
2343 * If this port wasn't just created, then we're reprobing because
2344 * we're coming out of suspend. In this case, always resend the link
2345 * address if there's an MSTB on this port
2347 if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2349 send_link_addr = true;
2351 if (port->connector)
2352 drm_modeset_unlock(&mgr->base.lock);
2353 else if (!port->input)
2354 drm_dp_mst_port_add_connector(mstb, port);
2356 if (send_link_addr && port->mstb) {
2357 ret = drm_dp_send_link_address(mgr, port->mstb);
2358 if (ret == 1) /* MSTB below us changed */
2364 /* put reference to this port */
2365 drm_dp_mst_topology_put_port(port);
2369 drm_dp_mst_topology_unlink_port(mgr, port);
2370 if (port->connector)
2371 drm_modeset_unlock(&mgr->base.lock);
2373 drm_dp_mst_topology_put_port(port);
2378 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2379 struct drm_dp_connection_status_notify *conn_stat)
2381 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2382 struct drm_dp_mst_port *port;
2383 int old_ddps, old_input, ret, i;
2386 bool dowork = false, create_connector = false;
2388 port = drm_dp_get_port(mstb, conn_stat->port_number);
2392 if (port->connector) {
2393 if (!port->input && conn_stat->input_port) {
2395 * We can't remove a connector from an already exposed
2396 * port, so just throw the port out and make sure we
2397 * reprobe the link address of it's parent MSTB
2399 drm_dp_mst_topology_unlink_port(mgr, port);
2400 mstb->link_address_sent = false;
2405 /* Locking is only needed if the port's exposed to userspace */
2406 drm_modeset_lock(&mgr->base.lock, NULL);
2407 } else if (port->input && !conn_stat->input_port) {
2408 create_connector = true;
2409 /* Reprobe link address so we get num_sdp_streams */
2410 mstb->link_address_sent = false;
2414 old_ddps = port->ddps;
2415 old_input = port->input;
2416 port->input = conn_stat->input_port;
2417 port->ldps = conn_stat->legacy_device_plug_status;
2418 port->ddps = conn_stat->displayport_device_plug_status;
2420 if (old_ddps != port->ddps) {
2421 if (port->ddps && !port->input)
2422 drm_dp_send_enum_path_resources(mgr, mstb, port);
2427 new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2428 new_mcs = conn_stat->message_capability_status;
2429 ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2432 } else if (ret < 0) {
2433 DRM_ERROR("Failed to change PDT for port %p: %d\n",
2438 if (!old_input && old_ddps != port->ddps && !port->ddps) {
2439 for (i = 0; i < mgr->max_payloads; i++) {
2440 struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
2441 struct drm_dp_mst_port *port_validated;
2447 container_of(vcpi, struct drm_dp_mst_port, vcpi);
2449 drm_dp_mst_topology_get_port_validated(mgr, port_validated);
2450 if (!port_validated) {
2451 mutex_lock(&mgr->payload_lock);
2452 vcpi->num_slots = 0;
2453 mutex_unlock(&mgr->payload_lock);
2455 drm_dp_mst_topology_put_port(port_validated);
2460 if (port->connector)
2461 drm_modeset_unlock(&mgr->base.lock);
2462 else if (create_connector)
2463 drm_dp_mst_port_add_connector(mstb, port);
2466 drm_dp_mst_topology_put_port(port);
2468 queue_work(system_long_wq, &mstb->mgr->work);
2471 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2474 struct drm_dp_mst_branch *mstb;
2475 struct drm_dp_mst_port *port;
2477 /* find the port by iterating down */
2479 mutex_lock(&mgr->lock);
2480 mstb = mgr->mst_primary;
2485 for (i = 0; i < lct - 1; i++) {
2486 int shift = (i % 2) ? 0 : 4;
2487 int port_num = (rad[i / 2] >> shift) & 0xf;
2489 list_for_each_entry(port, &mstb->ports, next) {
2490 if (port->port_num == port_num) {
2493 DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
2501 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2505 mutex_unlock(&mgr->lock);
2509 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2510 struct drm_dp_mst_branch *mstb,
2511 const uint8_t *guid)
2513 struct drm_dp_mst_branch *found_mstb;
2514 struct drm_dp_mst_port *port;
2516 if (memcmp(mstb->guid, guid, 16) == 0)
2520 list_for_each_entry(port, &mstb->ports, next) {
2524 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2533 static struct drm_dp_mst_branch *
2534 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2535 const uint8_t *guid)
2537 struct drm_dp_mst_branch *mstb;
2540 /* find the port by iterating down */
2541 mutex_lock(&mgr->lock);
2543 mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2545 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2550 mutex_unlock(&mgr->lock);
2554 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2555 struct drm_dp_mst_branch *mstb)
2557 struct drm_dp_mst_port *port;
2559 bool changed = false;
2561 if (!mstb->link_address_sent) {
2562 ret = drm_dp_send_link_address(mgr, mstb);
2569 list_for_each_entry(port, &mstb->ports, next) {
2570 struct drm_dp_mst_branch *mstb_child = NULL;
2572 if (port->input || !port->ddps)
2576 mstb_child = drm_dp_mst_topology_get_mstb_validated(
2580 ret = drm_dp_check_and_send_link_address(mgr,
2582 drm_dp_mst_topology_put_mstb(mstb_child);
2593 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2595 struct drm_dp_mst_topology_mgr *mgr =
2596 container_of(work, struct drm_dp_mst_topology_mgr, work);
2597 struct drm_device *dev = mgr->dev;
2598 struct drm_dp_mst_branch *mstb;
2600 bool clear_payload_id_table;
2602 mutex_lock(&mgr->probe_lock);
2604 mutex_lock(&mgr->lock);
2605 clear_payload_id_table = !mgr->payload_id_table_cleared;
2606 mgr->payload_id_table_cleared = true;
2608 mstb = mgr->mst_primary;
2610 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2614 mutex_unlock(&mgr->lock);
2616 mutex_unlock(&mgr->probe_lock);
2621 * Certain branch devices seem to incorrectly report an available_pbn
2622 * of 0 on downstream sinks, even after clearing the
2623 * DP_PAYLOAD_ALLOCATE_* registers in
2624 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2625 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2626 * things work again.
2628 if (clear_payload_id_table) {
2629 DRM_DEBUG_KMS("Clearing payload ID table\n");
2630 drm_dp_send_clear_payload_id_table(mgr, mstb);
2633 ret = drm_dp_check_and_send_link_address(mgr, mstb);
2634 drm_dp_mst_topology_put_mstb(mstb);
2636 mutex_unlock(&mgr->probe_lock);
2638 drm_kms_helper_hotplug_event(dev);
2641 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2646 if (memchr_inv(guid, 0, 16))
2649 salt = get_jiffies_64();
2651 memcpy(&guid[0], &salt, sizeof(u64));
2652 memcpy(&guid[8], &salt, sizeof(u64));
2657 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2658 u8 port_num, u32 offset, u8 num_bytes)
2660 struct drm_dp_sideband_msg_req_body req;
2662 req.req_type = DP_REMOTE_DPCD_READ;
2663 req.u.dpcd_read.port_number = port_num;
2664 req.u.dpcd_read.dpcd_address = offset;
2665 req.u.dpcd_read.num_bytes = num_bytes;
2666 drm_dp_encode_sideband_req(&req, msg);
2669 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2670 bool up, u8 *msg, int len)
2673 int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2674 int tosend, total, offset;
2681 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2683 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2686 if (ret != tosend) {
2687 if (ret == -EIO && retries < 5) {
2691 DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
2697 } while (total > 0);
2701 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2702 struct drm_dp_sideband_msg_tx *txmsg)
2704 struct drm_dp_mst_branch *mstb = txmsg->dst;
2707 req_type = txmsg->msg[0] & 0x7f;
2708 if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2709 req_type == DP_RESOURCE_STATUS_NOTIFY)
2713 hdr->path_msg = txmsg->path_msg;
2714 hdr->lct = mstb->lct;
2715 hdr->lcr = mstb->lct - 1;
2717 memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
2722 * process a single block of the next message in the sideband queue
2724 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2725 struct drm_dp_sideband_msg_tx *txmsg,
2729 struct drm_dp_sideband_msg_hdr hdr;
2730 int len, space, idx, tosend;
2733 if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2736 memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2738 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2739 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2741 /* make hdr from dst mst */
2742 ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2746 /* amount left to send in this message */
2747 len = txmsg->cur_len - txmsg->cur_offset;
2749 /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2750 space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2752 tosend = min(len, space);
2753 if (len == txmsg->cur_len)
2759 hdr.msg_len = tosend + 1;
2760 drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2761 memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2762 /* add crc at end */
2763 drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2766 ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2767 if (unlikely(ret) && drm_debug_enabled(DRM_UT_DP)) {
2768 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2770 drm_printf(&p, "sideband msg failed to send\n");
2771 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2775 txmsg->cur_offset += tosend;
2776 if (txmsg->cur_offset == txmsg->cur_len) {
2777 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2783 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2785 struct drm_dp_sideband_msg_tx *txmsg;
2788 WARN_ON(!mutex_is_locked(&mgr->qlock));
2790 /* construct a chunk from the first msg in the tx_msg queue */
2791 if (list_empty(&mgr->tx_msg_downq))
2794 txmsg = list_first_entry(&mgr->tx_msg_downq,
2795 struct drm_dp_sideband_msg_tx, next);
2796 ret = process_single_tx_qlock(mgr, txmsg, false);
2798 DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
2799 list_del(&txmsg->next);
2800 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2801 wake_up_all(&mgr->tx_waitq);
2805 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2806 struct drm_dp_sideband_msg_tx *txmsg)
2808 mutex_lock(&mgr->qlock);
2809 list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2811 if (drm_debug_enabled(DRM_UT_DP)) {
2812 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2814 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2817 if (list_is_singular(&mgr->tx_msg_downq))
2818 process_single_down_tx_qlock(mgr);
2819 mutex_unlock(&mgr->qlock);
2823 drm_dp_dump_link_address(struct drm_dp_link_address_ack_reply *reply)
2825 struct drm_dp_link_addr_reply_port *port_reply;
2828 for (i = 0; i < reply->nports; i++) {
2829 port_reply = &reply->ports[i];
2830 DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2832 port_reply->input_port,
2833 port_reply->peer_device_type,
2834 port_reply->port_number,
2835 port_reply->dpcd_revision,
2838 port_reply->legacy_device_plug_status,
2839 port_reply->num_sdp_streams,
2840 port_reply->num_sdp_stream_sinks);
2844 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2845 struct drm_dp_mst_branch *mstb)
2847 struct drm_dp_sideband_msg_tx *txmsg;
2848 struct drm_dp_link_address_ack_reply *reply;
2849 struct drm_dp_mst_port *port, *tmp;
2850 int i, ret, port_mask = 0;
2851 bool changed = false;
2853 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2858 build_link_address(txmsg);
2860 mstb->link_address_sent = true;
2861 drm_dp_queue_down_tx(mgr, txmsg);
2863 /* FIXME: Actually do some real error handling here */
2864 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2866 DRM_ERROR("Sending link address failed with %d\n", ret);
2869 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2870 DRM_ERROR("link address NAK received\n");
2875 reply = &txmsg->reply.u.link_addr;
2876 DRM_DEBUG_KMS("link address reply: %d\n", reply->nports);
2877 drm_dp_dump_link_address(reply);
2879 ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2883 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2884 DRM_ERROR("GUID check on %s failed: %d\n",
2889 for (i = 0; i < reply->nports; i++) {
2890 port_mask |= BIT(reply->ports[i].port_number);
2891 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2899 /* Prune any ports that are currently a part of mstb in our in-memory
2900 * topology, but were not seen in this link address. Usually this
2901 * means that they were removed while the topology was out of sync,
2902 * e.g. during suspend/resume
2904 mutex_lock(&mgr->lock);
2905 list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
2906 if (port_mask & BIT(port->port_num))
2909 DRM_DEBUG_KMS("port %d was not in link address, removing\n",
2911 list_del(&port->next);
2912 drm_dp_mst_topology_put_port(port);
2915 mutex_unlock(&mgr->lock);
2919 mstb->link_address_sent = false;
2921 return ret < 0 ? ret : changed;
2925 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
2926 struct drm_dp_mst_branch *mstb)
2928 struct drm_dp_sideband_msg_tx *txmsg;
2931 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2936 build_clear_payload_id_table(txmsg);
2938 drm_dp_queue_down_tx(mgr, txmsg);
2940 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2941 if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
2942 DRM_DEBUG_KMS("clear payload table id nak received\n");
2948 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
2949 struct drm_dp_mst_branch *mstb,
2950 struct drm_dp_mst_port *port)
2952 struct drm_dp_enum_path_resources_ack_reply *path_res;
2953 struct drm_dp_sideband_msg_tx *txmsg;
2956 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2961 build_enum_path_resources(txmsg, port->port_num);
2963 drm_dp_queue_down_tx(mgr, txmsg);
2965 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2968 path_res = &txmsg->reply.u.path_resources;
2970 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2971 DRM_DEBUG_KMS("enum path resources nak received\n");
2973 if (port->port_num != path_res->port_number)
2974 DRM_ERROR("got incorrect port in response\n");
2976 DRM_DEBUG_KMS("enum path resources %d: %d %d\n",
2977 path_res->port_number,
2978 path_res->full_payload_bw_number,
2979 path_res->avail_payload_bw_number);
2982 * If something changed, make sure we send a
2985 if (port->full_pbn != path_res->full_payload_bw_number ||
2986 port->fec_capable != path_res->fec_capable)
2989 port->full_pbn = path_res->full_payload_bw_number;
2990 port->fec_capable = path_res->fec_capable;
2998 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3000 if (!mstb->port_parent)
3003 if (mstb->port_parent->mstb != mstb)
3004 return mstb->port_parent;
3006 return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3010 * Searches upwards in the topology starting from mstb to try to find the
3011 * closest available parent of mstb that's still connected to the rest of the
3012 * topology. This can be used in order to perform operations like releasing
3013 * payloads, where the branch device which owned the payload may no longer be
3014 * around and thus would require that the payload on the last living relative
3017 static struct drm_dp_mst_branch *
3018 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3019 struct drm_dp_mst_branch *mstb,
3022 struct drm_dp_mst_branch *rmstb = NULL;
3023 struct drm_dp_mst_port *found_port;
3025 mutex_lock(&mgr->lock);
3026 if (!mgr->mst_primary)
3030 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3034 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3035 rmstb = found_port->parent;
3036 *port_num = found_port->port_num;
3038 /* Search again, starting from this parent */
3039 mstb = found_port->parent;
3043 mutex_unlock(&mgr->lock);
3047 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3048 struct drm_dp_mst_port *port,
3052 struct drm_dp_sideband_msg_tx *txmsg;
3053 struct drm_dp_mst_branch *mstb;
3055 u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3058 port_num = port->port_num;
3059 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3061 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3069 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3075 for (i = 0; i < port->num_sdp_streams; i++)
3079 build_allocate_payload(txmsg, port_num,
3081 pbn, port->num_sdp_streams, sinks);
3083 drm_dp_queue_down_tx(mgr, txmsg);
3086 * FIXME: there is a small chance that between getting the last
3087 * connected mstb and sending the payload message, the last connected
3088 * mstb could also be removed from the topology. In the future, this
3089 * needs to be fixed by restarting the
3090 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3091 * timeout if the topology is still connected to the system.
3093 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3095 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3102 drm_dp_mst_topology_put_mstb(mstb);
3106 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3107 struct drm_dp_mst_port *port, bool power_up)
3109 struct drm_dp_sideband_msg_tx *txmsg;
3112 port = drm_dp_mst_topology_get_port_validated(mgr, port);
3116 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3118 drm_dp_mst_topology_put_port(port);
3122 txmsg->dst = port->parent;
3123 build_power_updown_phy(txmsg, port->port_num, power_up);
3124 drm_dp_queue_down_tx(mgr, txmsg);
3126 ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3128 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3134 drm_dp_mst_topology_put_port(port);
3138 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3140 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3142 struct drm_dp_payload *payload)
3146 ret = drm_dp_dpcd_write_payload(mgr, id, payload);
3148 payload->payload_state = 0;
3151 payload->payload_state = DP_PAYLOAD_LOCAL;
3155 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3156 struct drm_dp_mst_port *port,
3158 struct drm_dp_payload *payload)
3161 ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3164 payload->payload_state = DP_PAYLOAD_REMOTE;
3168 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3169 struct drm_dp_mst_port *port,
3171 struct drm_dp_payload *payload)
3173 DRM_DEBUG_KMS("\n");
3174 /* it's okay for these to fail */
3176 drm_dp_payload_send_msg(mgr, port, id, 0);
3179 drm_dp_dpcd_write_payload(mgr, id, payload);
3180 payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3184 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3186 struct drm_dp_payload *payload)
3188 payload->payload_state = 0;
3193 * drm_dp_update_payload_part1() - Execute payload update part 1
3194 * @mgr: manager to use.
3196 * This iterates over all proposed virtual channels, and tries to
3197 * allocate space in the link for them. For 0->slots transitions,
3198 * this step just writes the VCPI to the MST device. For slots->0
3199 * transitions, this writes the updated VCPIs and removes the
3200 * remote VC payloads.
3202 * after calling this the driver should generate ACT and payload
3205 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
3207 struct drm_dp_payload req_payload;
3208 struct drm_dp_mst_port *port;
3212 mutex_lock(&mgr->payload_lock);
3213 for (i = 0; i < mgr->max_payloads; i++) {
3214 struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3215 struct drm_dp_payload *payload = &mgr->payloads[i];
3216 bool put_port = false;
3218 /* solve the current payloads - compare to the hw ones
3219 - update the hw view */
3220 req_payload.start_slot = cur_slots;
3222 port = container_of(vcpi, struct drm_dp_mst_port,
3225 /* Validated ports don't matter if we're releasing
3228 if (vcpi->num_slots) {
3229 port = drm_dp_mst_topology_get_port_validated(
3232 mutex_unlock(&mgr->payload_lock);
3238 req_payload.num_slots = vcpi->num_slots;
3239 req_payload.vcpi = vcpi->vcpi;
3242 req_payload.num_slots = 0;
3245 payload->start_slot = req_payload.start_slot;
3246 /* work out what is required to happen with this payload */
3247 if (payload->num_slots != req_payload.num_slots) {
3249 /* need to push an update for this payload */
3250 if (req_payload.num_slots) {
3251 drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3253 payload->num_slots = req_payload.num_slots;
3254 payload->vcpi = req_payload.vcpi;
3256 } else if (payload->num_slots) {
3257 payload->num_slots = 0;
3258 drm_dp_destroy_payload_step1(mgr, port,
3261 req_payload.payload_state =
3262 payload->payload_state;
3263 payload->start_slot = 0;
3265 payload->payload_state = req_payload.payload_state;
3267 cur_slots += req_payload.num_slots;
3270 drm_dp_mst_topology_put_port(port);
3273 for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3274 if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3279 DRM_DEBUG_KMS("removing payload %d\n", i);
3280 for (j = i; j < mgr->max_payloads - 1; j++) {
3281 mgr->payloads[j] = mgr->payloads[j + 1];
3282 mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3284 if (mgr->proposed_vcpis[j] &&
3285 mgr->proposed_vcpis[j]->num_slots) {
3286 set_bit(j + 1, &mgr->payload_mask);
3288 clear_bit(j + 1, &mgr->payload_mask);
3292 memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3293 sizeof(struct drm_dp_payload));
3294 mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3295 clear_bit(mgr->max_payloads, &mgr->payload_mask);
3297 mutex_unlock(&mgr->payload_lock);
3301 EXPORT_SYMBOL(drm_dp_update_payload_part1);
3304 * drm_dp_update_payload_part2() - Execute payload update part 2
3305 * @mgr: manager to use.
3307 * This iterates over all proposed virtual channels, and tries to
3308 * allocate space in the link for them. For 0->slots transitions,
3309 * this step writes the remote VC payload commands. For slots->0
3310 * this just resets some internal state.
3312 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3314 struct drm_dp_mst_port *port;
3317 mutex_lock(&mgr->payload_lock);
3318 for (i = 0; i < mgr->max_payloads; i++) {
3320 if (!mgr->proposed_vcpis[i])
3323 port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3325 DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
3326 if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3327 ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3328 } else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3329 ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3332 mutex_unlock(&mgr->payload_lock);
3336 mutex_unlock(&mgr->payload_lock);
3339 EXPORT_SYMBOL(drm_dp_update_payload_part2);
3341 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3342 struct drm_dp_mst_port *port,
3343 int offset, int size, u8 *bytes)
3346 struct drm_dp_sideband_msg_tx *txmsg;
3347 struct drm_dp_mst_branch *mstb;
3349 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3353 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3359 build_dpcd_read(txmsg, port->port_num, offset, size);
3360 txmsg->dst = port->parent;
3362 drm_dp_queue_down_tx(mgr, txmsg);
3364 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3368 /* DPCD read should never be NACKed */
3369 if (txmsg->reply.reply_type == 1) {
3370 DRM_ERROR("mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3371 mstb, port->port_num, offset, size);
3376 if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3381 ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3383 memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3388 drm_dp_mst_topology_put_mstb(mstb);
3393 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3394 struct drm_dp_mst_port *port,
3395 int offset, int size, u8 *bytes)
3398 struct drm_dp_sideband_msg_tx *txmsg;
3399 struct drm_dp_mst_branch *mstb;
3401 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3405 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3411 build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3414 drm_dp_queue_down_tx(mgr, txmsg);
3416 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3417 if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3422 drm_dp_mst_topology_put_mstb(mstb);
3426 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3428 struct drm_dp_sideband_msg_reply_body reply;
3430 reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3431 reply.req_type = req_type;
3432 drm_dp_encode_sideband_reply(&reply, msg);
3436 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3437 struct drm_dp_mst_branch *mstb,
3438 int req_type, bool broadcast)
3440 struct drm_dp_sideband_msg_tx *txmsg;
3442 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3447 drm_dp_encode_up_ack_reply(txmsg, req_type);
3449 mutex_lock(&mgr->qlock);
3450 /* construct a chunk from the first msg in the tx_msg queue */
3451 process_single_tx_qlock(mgr, txmsg, true);
3452 mutex_unlock(&mgr->qlock);
3458 static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8 dp_link_count)
3460 if (dp_link_bw == 0 || dp_link_count == 0)
3461 DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
3462 dp_link_bw, dp_link_count);
3464 return dp_link_bw * dp_link_count / 2;
3468 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3469 * @mgr: manager to set state for
3470 * @mst_state: true to enable MST on this connector - false to disable.
3472 * This is called by the driver when it detects an MST capable device plugged
3473 * into a DP MST capable port, or when a DP MST capable device is unplugged.
3475 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3478 struct drm_dp_mst_branch *mstb = NULL;
3480 mutex_lock(&mgr->payload_lock);
3481 mutex_lock(&mgr->lock);
3482 if (mst_state == mgr->mst_state)
3485 mgr->mst_state = mst_state;
3486 /* set the device into MST mode */
3488 struct drm_dp_payload reset_pay;
3490 WARN_ON(mgr->mst_primary);
3493 ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
3494 if (ret != DP_RECEIVER_CAP_SIZE) {
3495 DRM_DEBUG_KMS("failed to read DPCD\n");
3499 mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr->dpcd[1],
3500 mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK);
3501 if (mgr->pbn_div == 0) {
3506 /* add initial branch device at LCT 1 */
3507 mstb = drm_dp_add_mst_branch_device(1, NULL);
3514 /* give this the main reference */
3515 mgr->mst_primary = mstb;
3516 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3518 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3521 DP_UPSTREAM_IS_SRC);
3525 reset_pay.start_slot = 0;
3526 reset_pay.num_slots = 0x3f;
3527 drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3529 queue_work(system_long_wq, &mgr->work);
3533 /* disable MST on the device */
3534 mstb = mgr->mst_primary;
3535 mgr->mst_primary = NULL;
3536 /* this can fail if the device is gone */
3537 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3539 memset(mgr->payloads, 0,
3540 mgr->max_payloads * sizeof(mgr->payloads[0]));
3541 memset(mgr->proposed_vcpis, 0,
3542 mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3543 mgr->payload_mask = 0;
3544 set_bit(0, &mgr->payload_mask);
3546 mgr->payload_id_table_cleared = false;
3550 mutex_unlock(&mgr->lock);
3551 mutex_unlock(&mgr->payload_lock);
3553 drm_dp_mst_topology_put_mstb(mstb);
3557 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3560 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3562 struct drm_dp_mst_port *port;
3564 /* The link address will need to be re-sent on resume */
3565 mstb->link_address_sent = false;
3567 list_for_each_entry(port, &mstb->ports, next)
3569 drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3573 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3574 * @mgr: manager to suspend
3576 * This function tells the MST device that we can't handle UP messages
3577 * anymore. This should stop it from sending any since we are suspended.
3579 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3581 mutex_lock(&mgr->lock);
3582 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3583 DP_MST_EN | DP_UPSTREAM_IS_SRC);
3584 mutex_unlock(&mgr->lock);
3585 flush_work(&mgr->up_req_work);
3586 flush_work(&mgr->work);
3587 flush_work(&mgr->delayed_destroy_work);
3589 mutex_lock(&mgr->lock);
3590 if (mgr->mst_state && mgr->mst_primary)
3591 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3592 mutex_unlock(&mgr->lock);
3594 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3597 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3598 * @mgr: manager to resume
3599 * @sync: whether or not to perform topology reprobing synchronously
3601 * This will fetch DPCD and see if the device is still there,
3602 * if it is, it will rewrite the MSTM control bits, and return.
3604 * If the device fails this returns -1, and the driver should do
3605 * a full MST reprobe, in case we were undocked.
3607 * During system resume (where it is assumed that the driver will be calling
3608 * drm_atomic_helper_resume()) this function should be called beforehand with
3609 * @sync set to true. In contexts like runtime resume where the driver is not
3610 * expected to be calling drm_atomic_helper_resume(), this function should be
3611 * called with @sync set to false in order to avoid deadlocking.
3613 * Returns: -1 if the MST topology was removed while we were suspended, 0
3616 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3622 mutex_lock(&mgr->lock);
3623 if (!mgr->mst_primary)
3626 ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
3627 DP_RECEIVER_CAP_SIZE);
3628 if (ret != DP_RECEIVER_CAP_SIZE) {
3629 DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
3633 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3636 DP_UPSTREAM_IS_SRC);
3638 DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
3642 /* Some hubs forget their guids after they resume */
3643 ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3645 DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
3649 ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3651 DRM_DEBUG_KMS("check mstb failed - undocked during suspend?\n");
3656 * For the final step of resuming the topology, we need to bring the
3657 * state of our in-memory topology back into sync with reality. So,
3658 * restart the probing process as if we're probing a new hub
3660 queue_work(system_long_wq, &mgr->work);
3661 mutex_unlock(&mgr->lock);
3664 DRM_DEBUG_KMS("Waiting for link probe work to finish re-syncing topology...\n");
3665 flush_work(&mgr->work);
3671 mutex_unlock(&mgr->lock);
3674 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3677 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3678 struct drm_dp_mst_branch **mstb)
3682 int replylen, curreply;
3685 struct drm_dp_sideband_msg_hdr hdr;
3686 struct drm_dp_sideband_msg_rx *msg =
3687 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3688 int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3689 DP_SIDEBAND_MSG_DOWN_REP_BASE;
3694 len = min(mgr->max_dpcd_transaction_bytes, 16);
3695 ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3697 DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
3701 ret = drm_dp_decode_sideband_msg_hdr(&hdr, replyblock, len, &hdrlen);
3703 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3704 1, replyblock, len, false);
3705 DRM_DEBUG_KMS("ERROR: failed header\n");
3710 /* Caller is responsible for giving back this reference */
3711 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3713 DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
3719 if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3720 DRM_DEBUG_KMS("sideband msg set header failed %d\n",
3725 replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3726 ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3728 DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
3732 replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3734 while (replylen > 0) {
3735 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3736 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3739 DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n",
3744 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3746 DRM_DEBUG_KMS("failed to build sideband msg\n");
3756 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3758 struct drm_dp_sideband_msg_tx *txmsg;
3759 struct drm_dp_mst_branch *mstb = NULL;
3760 struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3762 if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3765 /* Multi-packet message transmission, don't clear the reply */
3766 if (!msg->have_eomt)
3769 /* find the message */
3770 mutex_lock(&mgr->qlock);
3771 txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3772 struct drm_dp_sideband_msg_tx, next);
3773 mutex_unlock(&mgr->qlock);
3775 /* Were we actually expecting a response, and from this mstb? */
3776 if (!txmsg || txmsg->dst != mstb) {
3777 struct drm_dp_sideband_msg_hdr *hdr;
3778 hdr = &msg->initial_hdr;
3779 DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
3780 mstb, hdr->seqno, hdr->lct, hdr->rad[0],
3782 goto out_clear_reply;
3785 drm_dp_sideband_parse_reply(msg, &txmsg->reply);
3787 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3788 DRM_DEBUG_KMS("Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3789 txmsg->reply.req_type,
3790 drm_dp_mst_req_type_str(txmsg->reply.req_type),
3791 txmsg->reply.u.nak.reason,
3792 drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3793 txmsg->reply.u.nak.nak_data);
3796 memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3797 drm_dp_mst_topology_put_mstb(mstb);
3799 mutex_lock(&mgr->qlock);
3800 txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3801 list_del(&txmsg->next);
3802 mutex_unlock(&mgr->qlock);
3804 wake_up_all(&mgr->tx_waitq);
3809 memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3812 drm_dp_mst_topology_put_mstb(mstb);
3818 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
3819 struct drm_dp_pending_up_req *up_req)
3821 struct drm_dp_mst_branch *mstb = NULL;
3822 struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
3823 struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
3824 bool hotplug = false;
3826 if (hdr->broadcast) {
3827 const u8 *guid = NULL;
3829 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
3830 guid = msg->u.conn_stat.guid;
3831 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
3832 guid = msg->u.resource_stat.guid;
3835 mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
3837 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
3841 DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
3846 /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
3847 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
3848 drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
3852 drm_dp_mst_topology_put_mstb(mstb);
3856 static void drm_dp_mst_up_req_work(struct work_struct *work)
3858 struct drm_dp_mst_topology_mgr *mgr =
3859 container_of(work, struct drm_dp_mst_topology_mgr,
3861 struct drm_dp_pending_up_req *up_req;
3862 bool send_hotplug = false;
3864 mutex_lock(&mgr->probe_lock);
3866 mutex_lock(&mgr->up_req_lock);
3867 up_req = list_first_entry_or_null(&mgr->up_req_list,
3868 struct drm_dp_pending_up_req,
3871 list_del(&up_req->next);
3872 mutex_unlock(&mgr->up_req_lock);
3877 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
3880 mutex_unlock(&mgr->probe_lock);
3883 drm_kms_helper_hotplug_event(mgr->dev);
3886 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
3888 struct drm_dp_pending_up_req *up_req;
3890 if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
3893 if (!mgr->up_req_recv.have_eomt)
3896 up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
3898 DRM_ERROR("Not enough memory to process MST up req\n");
3901 INIT_LIST_HEAD(&up_req->next);
3903 drm_dp_sideband_parse_req(&mgr->up_req_recv, &up_req->msg);
3905 if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
3906 up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
3907 DRM_DEBUG_KMS("Received unknown up req type, ignoring: %x\n",
3908 up_req->msg.req_type);
3913 drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
3916 if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
3917 const struct drm_dp_connection_status_notify *conn_stat =
3918 &up_req->msg.u.conn_stat;
3920 DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
3921 conn_stat->port_number,
3922 conn_stat->legacy_device_plug_status,
3923 conn_stat->displayport_device_plug_status,
3924 conn_stat->message_capability_status,
3925 conn_stat->input_port,
3926 conn_stat->peer_device_type);
3927 } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
3928 const struct drm_dp_resource_status_notify *res_stat =
3929 &up_req->msg.u.resource_stat;
3931 DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n",
3932 res_stat->port_number,
3933 res_stat->available_pbn);
3936 up_req->hdr = mgr->up_req_recv.initial_hdr;
3937 mutex_lock(&mgr->up_req_lock);
3938 list_add_tail(&up_req->next, &mgr->up_req_list);
3939 mutex_unlock(&mgr->up_req_lock);
3940 queue_work(system_long_wq, &mgr->up_req_work);
3943 memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
3948 * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
3949 * @mgr: manager to notify irq for.
3950 * @esi: 4 bytes from SINK_COUNT_ESI
3951 * @handled: whether the hpd interrupt was consumed or not
3953 * This should be called from the driver when it detects a short IRQ,
3954 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
3955 * topology manager will process the sideband messages received as a result
3958 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
3965 if (sc != mgr->sink_count) {
3966 mgr->sink_count = sc;
3970 if (esi[1] & DP_DOWN_REP_MSG_RDY) {
3971 ret = drm_dp_mst_handle_down_rep(mgr);
3975 if (esi[1] & DP_UP_REQ_MSG_RDY) {
3976 ret |= drm_dp_mst_handle_up_req(mgr);
3980 drm_dp_mst_kick_tx(mgr);
3983 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
3986 * drm_dp_mst_detect_port() - get connection status for an MST port
3987 * @connector: DRM connector for this port
3988 * @ctx: The acquisition context to use for grabbing locks
3989 * @mgr: manager for this port
3990 * @port: pointer to a port
3992 * This returns the current connection state for a port.
3995 drm_dp_mst_detect_port(struct drm_connector *connector,
3996 struct drm_modeset_acquire_ctx *ctx,
3997 struct drm_dp_mst_topology_mgr *mgr,
3998 struct drm_dp_mst_port *port)
4002 /* we need to search for the port in the mgr in case it's gone */
4003 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4005 return connector_status_disconnected;
4007 ret = drm_modeset_lock(&mgr->base.lock, ctx);
4011 ret = connector_status_disconnected;
4016 switch (port->pdt) {
4017 case DP_PEER_DEVICE_NONE:
4018 case DP_PEER_DEVICE_MST_BRANCHING:
4020 ret = connector_status_connected;
4023 case DP_PEER_DEVICE_SST_SINK:
4024 ret = connector_status_connected;
4025 /* for logical ports - cache the EDID */
4026 if (port->port_num >= 8 && !port->cached_edid) {
4027 port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4030 case DP_PEER_DEVICE_DP_LEGACY_CONV:
4032 ret = connector_status_connected;
4036 drm_dp_mst_topology_put_port(port);
4039 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4042 * drm_dp_mst_get_edid() - get EDID for an MST port
4043 * @connector: toplevel connector to get EDID for
4044 * @mgr: manager for this port
4045 * @port: unverified pointer to a port.
4047 * This returns an EDID for the port connected to a connector,
4048 * It validates the pointer still exists so the caller doesn't require a
4051 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4053 struct edid *edid = NULL;
4055 /* we need to search for the port in the mgr in case it's gone */
4056 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4060 if (port->cached_edid)
4061 edid = drm_edid_duplicate(port->cached_edid);
4063 edid = drm_get_edid(connector, &port->aux.ddc);
4065 port->has_audio = drm_detect_monitor_audio(edid);
4066 drm_dp_mst_topology_put_port(port);
4069 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4072 * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4073 * @mgr: manager to use
4074 * @pbn: payload bandwidth to convert into slots.
4076 * Calculate the number of VCPI slots that will be required for the given PBN
4077 * value. This function is deprecated, and should not be used in atomic
4081 * The total slots required for this port, or error.
4083 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4088 num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4090 /* max. time slots - one slot for MTP header */
4095 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4097 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4098 struct drm_dp_vcpi *vcpi, int pbn, int slots)
4102 /* max. time slots - one slot for MTP header */
4107 vcpi->aligned_pbn = slots * mgr->pbn_div;
4108 vcpi->num_slots = slots;
4110 ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4117 * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4118 * @state: global atomic state
4119 * @mgr: MST topology manager for the port
4120 * @port: port to find vcpi slots for
4121 * @pbn: bandwidth required for the mode in PBN
4122 * @pbn_div: divider for DSC mode that takes FEC into account
4124 * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4125 * may have had. Any atomic drivers which support MST must call this function
4126 * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4127 * current VCPI allocation for the new state, but only when
4128 * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4129 * to ensure compatibility with userspace applications that still use the
4130 * legacy modesetting UAPI.
4132 * Allocations set by this function are not checked against the bandwidth
4133 * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4135 * Additionally, it is OK to call this function multiple times on the same
4136 * @port as needed. It is not OK however, to call this function and
4137 * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4140 * drm_dp_atomic_release_vcpi_slots()
4141 * drm_dp_mst_atomic_check()
4144 * Total slots in the atomic state assigned for this port, or a negative error
4145 * code if the port no longer exists
4147 int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4148 struct drm_dp_mst_topology_mgr *mgr,
4149 struct drm_dp_mst_port *port, int pbn,
4152 struct drm_dp_mst_topology_state *topology_state;
4153 struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4154 int prev_slots, prev_bw, req_slots;
4156 topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4157 if (IS_ERR(topology_state))
4158 return PTR_ERR(topology_state);
4160 /* Find the current allocation for this port, if any */
4161 list_for_each_entry(pos, &topology_state->vcpis, next) {
4162 if (pos->port == port) {
4164 prev_slots = vcpi->vcpi;
4165 prev_bw = vcpi->pbn;
4168 * This should never happen, unless the driver tries
4169 * releasing and allocating the same VCPI allocation,
4172 if (WARN_ON(!prev_slots)) {
4173 DRM_ERROR("cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4187 pbn_div = mgr->pbn_div;
4189 req_slots = DIV_ROUND_UP(pbn, pbn_div);
4191 DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4192 port->connector->base.id, port->connector->name,
4193 port, prev_slots, req_slots);
4194 DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4195 port->connector->base.id, port->connector->name,
4196 port, prev_bw, pbn);
4198 /* Add the new allocation to the state */
4200 vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4204 drm_dp_mst_get_port_malloc(port);
4206 list_add(&vcpi->next, &topology_state->vcpis);
4208 vcpi->vcpi = req_slots;
4213 EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4216 * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4217 * @state: global atomic state
4218 * @mgr: MST topology manager for the port
4219 * @port: The port to release the VCPI slots from
4221 * Releases any VCPI slots that have been allocated to a port in the atomic
4222 * state. Any atomic drivers which support MST must call this function in
4223 * their &drm_connector_helper_funcs.atomic_check() callback when the
4224 * connector will no longer have VCPI allocated (e.g. because its CRTC was
4225 * removed) when it had VCPI allocated in the previous atomic state.
4227 * It is OK to call this even if @port has been removed from the system.
4228 * Additionally, it is OK to call this function multiple times on the same
4229 * @port as needed. It is not OK however, to call this function and
4230 * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4234 * drm_dp_atomic_find_vcpi_slots()
4235 * drm_dp_mst_atomic_check()
4238 * 0 if all slots for this port were added back to
4239 * &drm_dp_mst_topology_state.avail_slots or negative error code
4241 int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4242 struct drm_dp_mst_topology_mgr *mgr,
4243 struct drm_dp_mst_port *port)
4245 struct drm_dp_mst_topology_state *topology_state;
4246 struct drm_dp_vcpi_allocation *pos;
4249 topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4250 if (IS_ERR(topology_state))
4251 return PTR_ERR(topology_state);
4253 list_for_each_entry(pos, &topology_state->vcpis, next) {
4254 if (pos->port == port) {
4259 if (WARN_ON(!found)) {
4260 DRM_ERROR("no VCPI for [MST PORT:%p] found in mst state %p\n",
4261 port, &topology_state->base);
4265 DRM_DEBUG_ATOMIC("[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4267 drm_dp_mst_put_port_malloc(port);
4273 EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4276 * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4277 * @mgr: manager for this port
4278 * @port: port to allocate a virtual channel for.
4279 * @pbn: payload bandwidth number to request
4280 * @slots: returned number of slots for this PBN.
4282 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4283 struct drm_dp_mst_port *port, int pbn, int slots)
4287 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4294 if (port->vcpi.vcpi > 0) {
4295 DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4296 port->vcpi.vcpi, port->vcpi.pbn, pbn);
4297 if (pbn == port->vcpi.pbn) {
4298 drm_dp_mst_topology_put_port(port);
4303 ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4305 DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n",
4306 DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4309 DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",
4310 pbn, port->vcpi.num_slots);
4312 /* Keep port allocated until its payload has been removed */
4313 drm_dp_mst_get_port_malloc(port);
4314 drm_dp_mst_topology_put_port(port);
4319 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4321 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4324 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4328 slots = port->vcpi.num_slots;
4329 drm_dp_mst_topology_put_port(port);
4332 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
4335 * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
4336 * @mgr: manager for this port
4337 * @port: unverified pointer to a port.
4339 * This just resets the number of slots for the ports VCPI for later programming.
4341 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4344 * A port with VCPI will remain allocated until its VCPI is
4345 * released, no verified ref needed
4348 port->vcpi.num_slots = 0;
4350 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
4353 * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
4354 * @mgr: manager for this port
4355 * @port: port to deallocate vcpi for
4357 * This can be called unconditionally, regardless of whether
4358 * drm_dp_mst_allocate_vcpi() succeeded or not.
4360 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4361 struct drm_dp_mst_port *port)
4363 if (!port->vcpi.vcpi)
4366 drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
4367 port->vcpi.num_slots = 0;
4369 port->vcpi.aligned_pbn = 0;
4370 port->vcpi.vcpi = 0;
4371 drm_dp_mst_put_port_malloc(port);
4373 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
4375 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4376 int id, struct drm_dp_payload *payload)
4378 u8 payload_alloc[3], status;
4382 drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4383 DP_PAYLOAD_TABLE_UPDATED);
4385 payload_alloc[0] = id;
4386 payload_alloc[1] = payload->start_slot;
4387 payload_alloc[2] = payload->num_slots;
4389 ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4391 DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
4396 ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4398 DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
4402 if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4405 usleep_range(10000, 20000);
4408 DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
4417 static int do_get_act_status(struct drm_dp_aux *aux)
4422 ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4430 * drm_dp_check_act_status() - Polls for ACT handled status.
4431 * @mgr: manager to use
4433 * Tries waiting for the MST hub to finish updating it's payload table by
4434 * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4438 * 0 if the ACT was handled in time, negative error code on failure.
4440 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4443 * There doesn't seem to be any recommended retry count or timeout in
4444 * the MST specification. Since some hubs have been observed to take
4445 * over 1 second to update their payload allocations under certain
4446 * conditions, we use a rather large timeout value.
4448 const int timeout_ms = 3000;
4451 ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4452 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4453 200, timeout_ms * USEC_PER_MSEC);
4454 if (ret < 0 && status >= 0) {
4455 DRM_ERROR("Failed to get ACT after %dms, last status: %02x\n",
4456 timeout_ms, status);
4458 } else if (status < 0) {
4460 * Failure here isn't unexpected - the hub may have
4461 * just been unplugged
4463 DRM_DEBUG_KMS("Failed to read payload table status: %d\n",
4470 EXPORT_SYMBOL(drm_dp_check_act_status);
4473 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4474 * @clock: dot clock for the mode
4475 * @bpp: bpp for the mode.
4476 * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4478 * This uses the formula in the spec to calculate the PBN value for a mode.
4480 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4483 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4484 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4485 * common multiplier to render an integer PBN for all link rate/lane
4486 * counts combinations
4488 * peak_kbps *= (1006/1000)
4489 * peak_kbps *= (64/54)
4490 * peak_kbps *= 8 convert to bytes
4492 * If the bpp is in units of 1/16, further divide by 16. Put this
4493 * factor in the numerator rather than the denominator to avoid
4498 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4499 8 * 54 * 1000 * 1000);
4501 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4502 8 * 54 * 1000 * 1000);
4504 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4506 /* we want to kick the TX after we've ack the up/down IRQs. */
4507 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4509 queue_work(system_long_wq, &mgr->tx_work);
4512 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4513 struct drm_dp_mst_branch *mstb)
4515 struct drm_dp_mst_port *port;
4516 int tabs = mstb->lct;
4520 for (i = 0; i < tabs; i++)
4524 seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
4525 list_for_each_entry(port, &mstb->ports, next) {
4526 seq_printf(m, "%sport: %d: input: %d: pdt: %d, ddps: %d ldps: %d, sdp: %d/%d, %p, conn: %p\n", prefix, port->port_num, port->input, port->pdt, port->ddps, port->ldps, port->num_sdp_streams, port->num_sdp_stream_sinks, port, port->connector);
4528 drm_dp_mst_dump_mstb(m, port->mstb);
4532 #define DP_PAYLOAD_TABLE_SIZE 64
4534 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4539 for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4540 if (drm_dp_dpcd_read(mgr->aux,
4541 DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4548 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4549 struct drm_dp_mst_port *port, char *name,
4552 struct edid *mst_edid;
4554 mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4555 drm_edid_get_monitor_name(mst_edid, name, namelen);
4559 * drm_dp_mst_dump_topology(): dump topology to seq file.
4560 * @m: seq_file to dump output to
4561 * @mgr: manager to dump current topology for.
4563 * helper to dump MST topology to a seq file for debugfs.
4565 void drm_dp_mst_dump_topology(struct seq_file *m,
4566 struct drm_dp_mst_topology_mgr *mgr)
4569 struct drm_dp_mst_port *port;
4571 mutex_lock(&mgr->lock);
4572 if (mgr->mst_primary)
4573 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4576 mutex_unlock(&mgr->lock);
4578 mutex_lock(&mgr->payload_lock);
4579 seq_printf(m, "vcpi: %lx %lx %d\n", mgr->payload_mask, mgr->vcpi_mask,
4582 for (i = 0; i < mgr->max_payloads; i++) {
4583 if (mgr->proposed_vcpis[i]) {
4586 port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
4587 fetch_monitor_name(mgr, port, name, sizeof(name));
4588 seq_printf(m, "vcpi %d: %d %d %d sink name: %s\n", i,
4589 port->port_num, port->vcpi.vcpi,
4590 port->vcpi.num_slots,
4591 (*name != 0) ? name : "Unknown");
4593 seq_printf(m, "vcpi %d:unused\n", i);
4595 for (i = 0; i < mgr->max_payloads; i++) {
4596 seq_printf(m, "payload %d: %d, %d, %d\n",
4598 mgr->payloads[i].payload_state,
4599 mgr->payloads[i].start_slot,
4600 mgr->payloads[i].num_slots);
4604 mutex_unlock(&mgr->payload_lock);
4606 mutex_lock(&mgr->lock);
4607 if (mgr->mst_primary) {
4608 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4611 ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
4613 seq_printf(m, "dpcd read failed\n");
4616 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4618 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4620 seq_printf(m, "faux/mst read failed\n");
4623 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4625 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4627 seq_printf(m, "mst ctrl read failed\n");
4630 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4632 /* dump the standard OUI branch header */
4633 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4635 seq_printf(m, "branch oui read failed\n");
4638 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4640 for (i = 0x3; i < 0x8 && buf[i]; i++)
4641 seq_printf(m, "%c", buf[i]);
4642 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4643 buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4644 if (dump_dp_payload_table(mgr, buf))
4645 seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4649 mutex_unlock(&mgr->lock);
4652 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4654 static void drm_dp_tx_work(struct work_struct *work)
4656 struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4658 mutex_lock(&mgr->qlock);
4659 if (!list_empty(&mgr->tx_msg_downq))
4660 process_single_down_tx_qlock(mgr);
4661 mutex_unlock(&mgr->qlock);
4665 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4667 drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4669 if (port->connector) {
4670 drm_connector_unregister(port->connector);
4671 drm_connector_put(port->connector);
4674 drm_dp_mst_put_port_malloc(port);
4678 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4680 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4681 struct drm_dp_mst_port *port, *port_tmp;
4682 struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4683 bool wake_tx = false;
4685 mutex_lock(&mgr->lock);
4686 list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4687 list_del(&port->next);
4688 drm_dp_mst_topology_put_port(port);
4690 mutex_unlock(&mgr->lock);
4692 /* drop any tx slot msg */
4693 mutex_lock(&mstb->mgr->qlock);
4694 list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4695 if (txmsg->dst != mstb)
4698 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4699 list_del(&txmsg->next);
4702 mutex_unlock(&mstb->mgr->qlock);
4705 wake_up_all(&mstb->mgr->tx_waitq);
4707 drm_dp_mst_put_mstb_malloc(mstb);
4710 static void drm_dp_delayed_destroy_work(struct work_struct *work)
4712 struct drm_dp_mst_topology_mgr *mgr =
4713 container_of(work, struct drm_dp_mst_topology_mgr,
4714 delayed_destroy_work);
4715 bool send_hotplug = false, go_again;
4718 * Not a regular list traverse as we have to drop the destroy
4719 * connector lock before destroying the mstb/port, to avoid AB->BA
4720 * ordering between this lock and the config mutex.
4726 struct drm_dp_mst_branch *mstb;
4728 mutex_lock(&mgr->delayed_destroy_lock);
4729 mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
4730 struct drm_dp_mst_branch,
4733 list_del(&mstb->destroy_next);
4734 mutex_unlock(&mgr->delayed_destroy_lock);
4739 drm_dp_delayed_destroy_mstb(mstb);
4744 struct drm_dp_mst_port *port;
4746 mutex_lock(&mgr->delayed_destroy_lock);
4747 port = list_first_entry_or_null(&mgr->destroy_port_list,
4748 struct drm_dp_mst_port,
4751 list_del(&port->next);
4752 mutex_unlock(&mgr->delayed_destroy_lock);
4757 drm_dp_delayed_destroy_port(port);
4758 send_hotplug = true;
4764 drm_kms_helper_hotplug_event(mgr->dev);
4767 static struct drm_private_state *
4768 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
4770 struct drm_dp_mst_topology_state *state, *old_state =
4771 to_dp_mst_topology_state(obj->state);
4772 struct drm_dp_vcpi_allocation *pos, *vcpi;
4774 state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
4778 __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
4780 INIT_LIST_HEAD(&state->vcpis);
4782 list_for_each_entry(pos, &old_state->vcpis, next) {
4783 /* Prune leftover freed VCPI allocations */
4787 vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
4791 drm_dp_mst_get_port_malloc(vcpi->port);
4792 list_add(&vcpi->next, &state->vcpis);
4795 return &state->base;
4798 list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
4799 drm_dp_mst_put_port_malloc(pos->port);
4807 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
4808 struct drm_private_state *state)
4810 struct drm_dp_mst_topology_state *mst_state =
4811 to_dp_mst_topology_state(state);
4812 struct drm_dp_vcpi_allocation *pos, *tmp;
4814 list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
4815 /* We only keep references to ports with non-zero VCPIs */
4817 drm_dp_mst_put_port_malloc(pos->port);
4824 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
4825 struct drm_dp_mst_branch *branch)
4827 while (port->parent) {
4828 if (port->parent == branch)
4831 if (port->parent->port_parent)
4832 port = port->parent->port_parent;
4840 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
4841 struct drm_dp_mst_topology_state *state);
4844 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
4845 struct drm_dp_mst_topology_state *state)
4847 struct drm_dp_vcpi_allocation *vcpi;
4848 struct drm_dp_mst_port *port;
4849 int pbn_used = 0, ret;
4852 /* Check that we have at least one port in our state that's downstream
4853 * of this branch, otherwise we can skip this branch
4855 list_for_each_entry(vcpi, &state->vcpis, next) {
4857 !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
4866 if (mstb->port_parent)
4867 DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
4868 mstb->port_parent->parent, mstb->port_parent,
4871 DRM_DEBUG_ATOMIC("[MSTB:%p] Checking bandwidth limits\n",
4874 list_for_each_entry(port, &mstb->ports, next) {
4875 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
4886 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
4887 struct drm_dp_mst_topology_state *state)
4889 struct drm_dp_vcpi_allocation *vcpi;
4892 if (port->pdt == DP_PEER_DEVICE_NONE)
4895 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
4898 list_for_each_entry(vcpi, &state->vcpis, next) {
4899 if (vcpi->port != port)
4910 /* This should never happen, as it means we tried to
4911 * set a mode before querying the full_pbn
4913 if (WARN_ON(!port->full_pbn))
4916 pbn_used = vcpi->pbn;
4918 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
4924 if (pbn_used > port->full_pbn) {
4925 DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
4926 port->parent, port, pbn_used,
4931 DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
4932 port->parent, port, pbn_used, port->full_pbn);
4938 drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
4939 struct drm_dp_mst_topology_state *mst_state)
4941 struct drm_dp_vcpi_allocation *vcpi;
4942 int avail_slots = 63, payload_count = 0;
4944 list_for_each_entry(vcpi, &mst_state->vcpis, next) {
4945 /* Releasing VCPI is always OK-even if the port is gone */
4947 DRM_DEBUG_ATOMIC("[MST PORT:%p] releases all VCPI slots\n",
4952 DRM_DEBUG_ATOMIC("[MST PORT:%p] requires %d vcpi slots\n",
4953 vcpi->port, vcpi->vcpi);
4955 avail_slots -= vcpi->vcpi;
4956 if (avail_slots < 0) {
4957 DRM_DEBUG_ATOMIC("[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
4958 vcpi->port, mst_state,
4959 avail_slots + vcpi->vcpi);
4963 if (++payload_count > mgr->max_payloads) {
4964 DRM_DEBUG_ATOMIC("[MST MGR:%p] state %p has too many payloads (max=%d)\n",
4965 mgr, mst_state, mgr->max_payloads);
4969 DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
4970 mgr, mst_state, avail_slots,
4977 * drm_dp_mst_add_affected_dsc_crtcs
4978 * @state: Pointer to the new struct drm_dp_mst_topology_state
4979 * @mgr: MST topology manager
4981 * Whenever there is a change in mst topology
4982 * DSC configuration would have to be recalculated
4983 * therefore we need to trigger modeset on all affected
4984 * CRTCs in that topology
4987 * drm_dp_mst_atomic_enable_dsc()
4989 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
4991 struct drm_dp_mst_topology_state *mst_state;
4992 struct drm_dp_vcpi_allocation *pos;
4993 struct drm_connector *connector;
4994 struct drm_connector_state *conn_state;
4995 struct drm_crtc *crtc;
4996 struct drm_crtc_state *crtc_state;
4998 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5000 if (IS_ERR(mst_state))
5003 list_for_each_entry(pos, &mst_state->vcpis, next) {
5005 connector = pos->port->connector;
5010 conn_state = drm_atomic_get_connector_state(state, connector);
5012 if (IS_ERR(conn_state))
5013 return PTR_ERR(conn_state);
5015 crtc = conn_state->crtc;
5020 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5023 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5025 if (IS_ERR(crtc_state))
5026 return PTR_ERR(crtc_state);
5028 DRM_DEBUG_ATOMIC("[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5031 crtc_state->mode_changed = true;
5035 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5038 * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5039 * @state: Pointer to the new drm_atomic_state
5040 * @port: Pointer to the affected MST Port
5041 * @pbn: Newly recalculated bw required for link with DSC enabled
5042 * @pbn_div: Divider to calculate correct number of pbn per slot
5043 * @enable: Boolean flag to enable or disable DSC on the port
5045 * This function enables DSC on the given Port
5046 * by recalculating its vcpi from pbn provided
5047 * and sets dsc_enable flag to keep track of which
5048 * ports have DSC enabled
5051 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5052 struct drm_dp_mst_port *port,
5053 int pbn, int pbn_div,
5056 struct drm_dp_mst_topology_state *mst_state;
5057 struct drm_dp_vcpi_allocation *pos;
5061 mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5063 if (IS_ERR(mst_state))
5064 return PTR_ERR(mst_state);
5066 list_for_each_entry(pos, &mst_state->vcpis, next) {
5067 if (pos->port == port) {
5074 DRM_DEBUG_ATOMIC("[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
5079 if (pos->dsc_enabled == enable) {
5080 DRM_DEBUG_ATOMIC("[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
5081 port, enable, pos->vcpi);
5086 vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
5087 DRM_DEBUG_ATOMIC("[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
5093 pos->dsc_enabled = enable;
5097 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5099 * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5100 * atomic update is valid
5101 * @state: Pointer to the new &struct drm_dp_mst_topology_state
5103 * Checks the given topology state for an atomic update to ensure that it's
5104 * valid. This includes checking whether there's enough bandwidth to support
5105 * the new VCPI allocations in the atomic update.
5107 * Any atomic drivers supporting DP MST must make sure to call this after
5108 * checking the rest of their state in their
5109 * &drm_mode_config_funcs.atomic_check() callback.
5112 * drm_dp_atomic_find_vcpi_slots()
5113 * drm_dp_atomic_release_vcpi_slots()
5117 * 0 if the new state is valid, negative error code otherwise.
5119 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5121 struct drm_dp_mst_topology_mgr *mgr;
5122 struct drm_dp_mst_topology_state *mst_state;
5125 for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5126 if (!mgr->mst_state)
5129 ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
5133 mutex_lock(&mgr->lock);
5134 ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5136 mutex_unlock(&mgr->lock);
5145 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5147 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5148 .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5149 .atomic_destroy_state = drm_dp_mst_destroy_state,
5151 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5154 * drm_atomic_get_mst_topology_state: get MST topology state
5156 * @state: global atomic state
5157 * @mgr: MST topology manager, also the private object in this case
5159 * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5160 * state vtable so that the private object state returned is that of a MST
5161 * topology object. Also, drm_atomic_get_private_obj_state() expects the caller
5162 * to care of the locking, so warn if don't hold the connection_mutex.
5166 * The MST topology state or error pointer.
5168 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5169 struct drm_dp_mst_topology_mgr *mgr)
5171 return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5173 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5176 * drm_dp_mst_topology_mgr_init - initialise a topology manager
5177 * @mgr: manager struct to initialise
5178 * @dev: device providing this structure - for i2c addition.
5179 * @aux: DP helper aux channel to talk to this device
5180 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5181 * @max_payloads: maximum number of payloads this GPU can source
5182 * @conn_base_id: the connector object ID the MST device is connected to.
5184 * Return 0 for success, or negative error code on failure
5186 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5187 struct drm_device *dev, struct drm_dp_aux *aux,
5188 int max_dpcd_transaction_bytes,
5189 int max_payloads, int conn_base_id)
5191 struct drm_dp_mst_topology_state *mst_state;
5193 mutex_init(&mgr->lock);
5194 mutex_init(&mgr->qlock);
5195 mutex_init(&mgr->payload_lock);
5196 mutex_init(&mgr->delayed_destroy_lock);
5197 mutex_init(&mgr->up_req_lock);
5198 mutex_init(&mgr->probe_lock);
5199 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5200 mutex_init(&mgr->topology_ref_history_lock);
5202 INIT_LIST_HEAD(&mgr->tx_msg_downq);
5203 INIT_LIST_HEAD(&mgr->destroy_port_list);
5204 INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5205 INIT_LIST_HEAD(&mgr->up_req_list);
5208 * delayed_destroy_work will be queued on a dedicated WQ, so that any
5209 * requeuing will be also flushed when deiniting the topology manager.
5211 mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5212 if (mgr->delayed_destroy_wq == NULL)
5215 INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5216 INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5217 INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5218 INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5219 init_waitqueue_head(&mgr->tx_waitq);
5222 mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5223 mgr->max_payloads = max_payloads;
5224 mgr->conn_base_id = conn_base_id;
5225 if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5226 max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5228 mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5231 mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5232 if (!mgr->proposed_vcpis)
5234 set_bit(0, &mgr->payload_mask);
5236 mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5237 if (mst_state == NULL)
5240 mst_state->mgr = mgr;
5241 INIT_LIST_HEAD(&mst_state->vcpis);
5243 drm_atomic_private_obj_init(dev, &mgr->base,
5245 &drm_dp_mst_topology_state_funcs);
5249 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5252 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5253 * @mgr: manager to destroy
5255 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5257 drm_dp_mst_topology_mgr_set_mst(mgr, false);
5258 flush_work(&mgr->work);
5259 /* The following will also drain any requeued work on the WQ. */
5260 if (mgr->delayed_destroy_wq) {
5261 destroy_workqueue(mgr->delayed_destroy_wq);
5262 mgr->delayed_destroy_wq = NULL;
5264 mutex_lock(&mgr->payload_lock);
5265 kfree(mgr->payloads);
5266 mgr->payloads = NULL;
5267 kfree(mgr->proposed_vcpis);
5268 mgr->proposed_vcpis = NULL;
5269 mutex_unlock(&mgr->payload_lock);
5272 drm_atomic_private_obj_fini(&mgr->base);
5275 mutex_destroy(&mgr->delayed_destroy_lock);
5276 mutex_destroy(&mgr->payload_lock);
5277 mutex_destroy(&mgr->qlock);
5278 mutex_destroy(&mgr->lock);
5279 mutex_destroy(&mgr->up_req_lock);
5280 mutex_destroy(&mgr->probe_lock);
5281 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5282 mutex_destroy(&mgr->topology_ref_history_lock);
5285 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5287 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5291 if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5294 for (i = 0; i < num - 1; i++) {
5295 if (msgs[i].flags & I2C_M_RD ||
5300 return msgs[num - 1].flags & I2C_M_RD &&
5301 msgs[num - 1].len <= 0xff;
5305 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
5308 struct drm_dp_aux *aux = adapter->algo_data;
5309 struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
5310 struct drm_dp_mst_branch *mstb;
5311 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5313 struct drm_dp_sideband_msg_req_body msg;
5314 struct drm_dp_sideband_msg_tx *txmsg = NULL;
5317 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5321 if (!remote_i2c_read_ok(msgs, num)) {
5322 DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
5327 memset(&msg, 0, sizeof(msg));
5328 msg.req_type = DP_REMOTE_I2C_READ;
5329 msg.u.i2c_read.num_transactions = num - 1;
5330 msg.u.i2c_read.port_number = port->port_num;
5331 for (i = 0; i < num - 1; i++) {
5332 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5333 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5334 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5335 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5337 msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5338 msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5340 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5347 drm_dp_encode_sideband_req(&msg, txmsg);
5349 drm_dp_queue_down_tx(mgr, txmsg);
5351 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5354 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5358 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5362 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5367 drm_dp_mst_topology_put_mstb(mstb);
5371 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5373 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5374 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5375 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5376 I2C_FUNC_10BIT_ADDR;
5379 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5380 .functionality = drm_dp_mst_i2c_functionality,
5381 .master_xfer = drm_dp_mst_i2c_xfer,
5385 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5386 * @port: The port to add the I2C bus on
5388 * Returns 0 on success or a negative error code on failure.
5390 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5392 struct drm_dp_aux *aux = &port->aux;
5393 struct device *parent_dev = port->mgr->dev->dev;
5395 aux->ddc.algo = &drm_dp_mst_i2c_algo;
5396 aux->ddc.algo_data = aux;
5397 aux->ddc.retries = 3;
5399 aux->ddc.class = I2C_CLASS_DDC;
5400 aux->ddc.owner = THIS_MODULE;
5401 /* FIXME: set the kdev of the port's connector as parent */
5402 aux->ddc.dev.parent = parent_dev;
5403 aux->ddc.dev.of_node = parent_dev->of_node;
5405 strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5406 sizeof(aux->ddc.name));
5408 return i2c_add_adapter(&aux->ddc);
5412 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5413 * @port: The port to remove the I2C bus from
5415 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5417 i2c_del_adapter(&port->aux.ddc);
5421 * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5422 * @port: The port to check
5424 * A single physical MST hub object can be represented in the topology
5425 * by multiple branches, with virtual ports between those branches.
5427 * As of DP1.4, An MST hub with internal (virtual) ports must expose
5428 * certain DPCD registers over those ports. See sections 2.6.1.1.1
5429 * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5431 * May acquire mgr->lock
5434 * true if the port is a virtual DP peer device, false otherwise
5436 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5438 struct drm_dp_mst_port *downstream_port;
5440 if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5443 /* Virtual DP Sink (Internal Display Panel) */
5444 if (port->port_num >= 8)
5447 /* DP-to-HDMI Protocol Converter */
5448 if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5454 mutex_lock(&port->mgr->lock);
5455 if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5457 port->mstb->num_ports == 2) {
5458 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5459 if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5460 !downstream_port->input) {
5461 mutex_unlock(&port->mgr->lock);
5466 mutex_unlock(&port->mgr->lock);
5472 * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5473 * @port: The port to check. A leaf of the MST tree with an attached display.
5475 * Depending on the situation, DSC may be enabled via the endpoint aux,
5476 * the immediately upstream aux, or the connector's physical aux.
5478 * This is both the correct aux to read DSC_CAPABILITY and the
5479 * correct aux to write DSC_ENABLED.
5481 * This operation can be expensive (up to four aux reads), so
5482 * the caller should cache the return.
5485 * NULL if DSC cannot be enabled on this port, otherwise the aux device
5487 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5489 struct drm_dp_mst_port *immediate_upstream_port;
5490 struct drm_dp_mst_port *fec_port;
5491 struct drm_dp_desc desc = {};
5498 if (port->parent->port_parent)
5499 immediate_upstream_port = port->parent->port_parent;
5501 immediate_upstream_port = NULL;
5503 fec_port = immediate_upstream_port;
5506 * Each physical link (i.e. not a virtual port) between the
5507 * output and the primary device must support FEC
5509 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5510 !fec_port->fec_capable)
5513 fec_port = fec_port->parent->port_parent;
5516 /* DP-to-DP peer device */
5517 if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5520 if (drm_dp_dpcd_read(&port->aux,
5521 DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5523 if (drm_dp_dpcd_read(&port->aux,
5524 DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5526 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5527 DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5530 /* Enpoint decompression with DP-to-DP peer device */
5531 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5532 (endpoint_fec & DP_FEC_CAPABLE) &&
5533 (upstream_dsc & 0x2) /* DSC passthrough */)
5536 /* Virtual DPCD decompression with DP-to-DP peer device */
5537 return &immediate_upstream_port->aux;
5540 /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5541 if (drm_dp_mst_is_virtual_dpcd(port))
5546 * Applies to ports for which:
5547 * - Physical aux has Synaptics OUI
5548 * - DPv1.4 or higher
5549 * - Port is on primary branch device
5550 * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5552 if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5555 if (drm_dp_has_quirk(&desc, 0,
5556 DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5557 port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5558 port->parent == port->mgr->mst_primary) {
5561 if (drm_dp_dpcd_read(&port->aux, DP_DOWNSTREAMPORT_PRESENT,
5562 &downstreamport, 1) < 0)
5565 if ((downstreamport & DP_DWN_STRM_PORT_PRESENT) &&
5566 ((downstreamport & DP_DWN_STRM_PORT_TYPE_MASK)
5567 != DP_DWN_STRM_PORT_TYPE_ANALOG))
5568 return port->mgr->aux;
5572 * The check below verifies if the MST sink
5573 * connected to the GPU is capable of DSC -
5574 * therefore the endpoint needs to be
5575 * both DSC and FEC capable.
5577 if (drm_dp_dpcd_read(&port->aux,
5578 DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5580 if (drm_dp_dpcd_read(&port->aux,
5581 DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5583 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5584 (endpoint_fec & DP_FEC_CAPABLE))
5589 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);