1 // SPDX-License-Identifier: GPL-2.0+
3 * BCM2835 DMA engine support
5 * Author: Florian Meier <florian.meier@koalo.de>
9 * OMAP DMAengine support by Russell King
12 * Copyright (C) 2010 Broadcom
14 * Raspberry Pi PCM I2S ALSA Driver
15 * Copyright (c) by Phil Poole 2013
17 * MARVELL MMP Peripheral DMA Driver
18 * Copyright 2012 Marvell International Ltd.
20 #include <linux/dmaengine.h>
21 #include <linux/dma-mapping.h>
22 #include <linux/dmapool.h>
23 #include <linux/err.h>
24 #include <linux/init.h>
25 #include <linux/interrupt.h>
26 #include <linux/list.h>
27 #include <linux/module.h>
28 #include <linux/platform_device.h>
29 #include <linux/slab.h>
31 #include <linux/spinlock.h>
33 #include <linux/of_dma.h>
37 #define BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED 14
38 #define BCM2835_DMA_CHAN_NAME_SIZE 8
41 * struct bcm2835_dmadev - BCM2835 DMA controller
43 * @base: base address of register map
44 * @dma_parms: DMA parameters (to convey 1 GByte max segment size to clients)
46 struct bcm2835_dmadev {
47 struct dma_device ddev;
49 struct device_dma_parameters dma_parms;
52 struct bcm2835_dma_cb {
62 struct bcm2835_cb_entry {
63 struct bcm2835_dma_cb *cb;
68 struct virt_dma_chan vc;
70 struct dma_slave_config cfg;
74 struct bcm2835_desc *desc;
75 struct dma_pool *cb_pool;
77 void __iomem *chan_base;
79 unsigned int irq_flags;
85 struct bcm2835_chan *c;
86 struct virt_dma_desc vd;
87 enum dma_transfer_direction dir;
94 struct bcm2835_cb_entry cb_list[];
97 #define BCM2835_DMA_CS 0x00
98 #define BCM2835_DMA_ADDR 0x04
99 #define BCM2835_DMA_TI 0x08
100 #define BCM2835_DMA_SOURCE_AD 0x0c
101 #define BCM2835_DMA_DEST_AD 0x10
102 #define BCM2835_DMA_LEN 0x14
103 #define BCM2835_DMA_STRIDE 0x18
104 #define BCM2835_DMA_NEXTCB 0x1c
105 #define BCM2835_DMA_DEBUG 0x20
107 /* DMA CS Control and Status bits */
108 #define BCM2835_DMA_ACTIVE BIT(0) /* activate the DMA */
109 #define BCM2835_DMA_END BIT(1) /* current CB has ended */
110 #define BCM2835_DMA_INT BIT(2) /* interrupt status */
111 #define BCM2835_DMA_DREQ BIT(3) /* DREQ state */
112 #define BCM2835_DMA_ISPAUSED BIT(4) /* Pause requested or not active */
113 #define BCM2835_DMA_ISHELD BIT(5) /* Is held by DREQ flow control */
114 #define BCM2835_DMA_WAITING_FOR_WRITES BIT(6) /* waiting for last
117 #define BCM2835_DMA_ERR BIT(8)
118 #define BCM2835_DMA_PRIORITY(x) ((x & 15) << 16) /* AXI priority */
119 #define BCM2835_DMA_PANIC_PRIORITY(x) ((x & 15) << 20) /* panic priority */
120 /* current value of TI.BCM2835_DMA_WAIT_RESP */
121 #define BCM2835_DMA_WAIT_FOR_WRITES BIT(28)
122 #define BCM2835_DMA_DIS_DEBUG BIT(29) /* disable debug pause signal */
123 #define BCM2835_DMA_ABORT BIT(30) /* Stop current CB, go to next, WO */
124 #define BCM2835_DMA_RESET BIT(31) /* WO, self clearing */
126 /* Transfer information bits - also bcm2835_cb.info field */
127 #define BCM2835_DMA_INT_EN BIT(0)
128 #define BCM2835_DMA_TDMODE BIT(1) /* 2D-Mode */
129 #define BCM2835_DMA_WAIT_RESP BIT(3) /* wait for AXI-write to be acked */
130 #define BCM2835_DMA_D_INC BIT(4)
131 #define BCM2835_DMA_D_WIDTH BIT(5) /* 128bit writes if set */
132 #define BCM2835_DMA_D_DREQ BIT(6) /* enable DREQ for destination */
133 #define BCM2835_DMA_D_IGNORE BIT(7) /* ignore destination writes */
134 #define BCM2835_DMA_S_INC BIT(8)
135 #define BCM2835_DMA_S_WIDTH BIT(9) /* 128bit writes if set */
136 #define BCM2835_DMA_S_DREQ BIT(10) /* enable SREQ for source */
137 #define BCM2835_DMA_S_IGNORE BIT(11) /* ignore source reads - read 0 */
138 #define BCM2835_DMA_BURST_LENGTH(x) ((x & 15) << 12)
139 #define BCM2835_DMA_PER_MAP(x) ((x & 31) << 16) /* REQ source */
140 #define BCM2835_DMA_WAIT(x) ((x & 31) << 21) /* add DMA-wait cycles */
141 #define BCM2835_DMA_NO_WIDE_BURSTS BIT(26) /* no 2 beat write bursts */
143 /* debug register bits */
144 #define BCM2835_DMA_DEBUG_LAST_NOT_SET_ERR BIT(0)
145 #define BCM2835_DMA_DEBUG_FIFO_ERR BIT(1)
146 #define BCM2835_DMA_DEBUG_READ_ERR BIT(2)
147 #define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_SHIFT 4
148 #define BCM2835_DMA_DEBUG_OUTSTANDING_WRITES_BITS 4
149 #define BCM2835_DMA_DEBUG_ID_SHIFT 16
150 #define BCM2835_DMA_DEBUG_ID_BITS 9
151 #define BCM2835_DMA_DEBUG_STATE_SHIFT 16
152 #define BCM2835_DMA_DEBUG_STATE_BITS 9
153 #define BCM2835_DMA_DEBUG_VERSION_SHIFT 25
154 #define BCM2835_DMA_DEBUG_VERSION_BITS 3
155 #define BCM2835_DMA_DEBUG_LITE BIT(28)
157 /* shared registers for all dma channels */
158 #define BCM2835_DMA_INT_STATUS 0xfe0
159 #define BCM2835_DMA_ENABLE 0xff0
161 #define BCM2835_DMA_DATA_TYPE_S8 1
162 #define BCM2835_DMA_DATA_TYPE_S16 2
163 #define BCM2835_DMA_DATA_TYPE_S32 4
164 #define BCM2835_DMA_DATA_TYPE_S128 16
166 /* Valid only for channels 0 - 14, 15 has its own base address */
167 #define BCM2835_DMA_CHAN(n) ((n) << 8) /* Base address */
168 #define BCM2835_DMA_CHANIO(base, n) ((base) + BCM2835_DMA_CHAN(n))
170 /* the max dma length for different channels */
171 #define MAX_DMA_LEN SZ_1G
172 #define MAX_LITE_DMA_LEN (SZ_64K - 4)
174 static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c)
176 /* lite and normal channels have different max frame length */
177 return c->is_lite_channel ? MAX_LITE_DMA_LEN : MAX_DMA_LEN;
180 /* how many frames of max_len size do we need to transfer len bytes */
181 static inline size_t bcm2835_dma_frames_for_length(size_t len,
184 return DIV_ROUND_UP(len, max_len);
187 static inline struct bcm2835_dmadev *to_bcm2835_dma_dev(struct dma_device *d)
189 return container_of(d, struct bcm2835_dmadev, ddev);
192 static inline struct bcm2835_chan *to_bcm2835_dma_chan(struct dma_chan *c)
194 return container_of(c, struct bcm2835_chan, vc.chan);
197 static inline struct bcm2835_desc *to_bcm2835_dma_desc(
198 struct dma_async_tx_descriptor *t)
200 return container_of(t, struct bcm2835_desc, vd.tx);
203 static void bcm2835_dma_free_cb_chain(struct bcm2835_desc *desc)
207 for (i = 0; i < desc->frames; i++)
208 dma_pool_free(desc->c->cb_pool, desc->cb_list[i].cb,
209 desc->cb_list[i].paddr);
214 static void bcm2835_dma_desc_free(struct virt_dma_desc *vd)
216 bcm2835_dma_free_cb_chain(
217 container_of(vd, struct bcm2835_desc, vd));
220 static void bcm2835_dma_create_cb_set_length(
221 struct bcm2835_chan *chan,
222 struct bcm2835_dma_cb *control_block,
228 size_t max_len = bcm2835_dma_max_frame_length(chan);
230 /* set the length taking lite-channel limitations into account */
231 control_block->length = min_t(u32, len, max_len);
233 /* finished if we have no period_length */
238 * period_len means: that we need to generate
239 * transfers that are terminating at every
240 * multiple of period_len - this is typically
241 * used to set the interrupt flag in info
242 * which is required during cyclic transfers
245 /* have we filled in period_length yet? */
246 if (*total_len + control_block->length < period_len) {
247 /* update number of bytes in this period so far */
248 *total_len += control_block->length;
252 /* calculate the length that remains to reach period_length */
253 control_block->length = period_len - *total_len;
255 /* reset total_length for next period */
258 /* add extrainfo bits in info */
259 control_block->info |= finalextrainfo;
262 static inline size_t bcm2835_dma_count_frames_for_sg(
263 struct bcm2835_chan *c,
264 struct scatterlist *sgl,
268 struct scatterlist *sgent;
270 size_t plength = bcm2835_dma_max_frame_length(c);
272 for_each_sg(sgl, sgent, sg_len, i)
273 frames += bcm2835_dma_frames_for_length(
274 sg_dma_len(sgent), plength);
280 * bcm2835_dma_create_cb_chain - create a control block and fills data in
282 * @chan: the @dma_chan for which we run this
283 * @direction: the direction in which we transfer
284 * @cyclic: it is a cyclic transfer
285 * @info: the default info bits to apply per controlblock
286 * @frames: number of controlblocks to allocate
287 * @src: the src address to assign (if the S_INC bit is set
288 * in @info, then it gets incremented)
289 * @dst: the dst address to assign (if the D_INC bit is set
290 * in @info, then it gets incremented)
291 * @buf_len: the full buffer length (may also be 0)
292 * @period_len: the period length when to apply @finalextrainfo
293 * in addition to the last transfer
294 * this will also break some control-blocks early
295 * @finalextrainfo: additional bits in last controlblock
296 * (or when period_len is reached in case of cyclic)
297 * @gfp: the GFP flag to use for allocation
299 static struct bcm2835_desc *bcm2835_dma_create_cb_chain(
300 struct dma_chan *chan, enum dma_transfer_direction direction,
301 bool cyclic, u32 info, u32 finalextrainfo, size_t frames,
302 dma_addr_t src, dma_addr_t dst, size_t buf_len,
303 size_t period_len, gfp_t gfp)
305 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
306 size_t len = buf_len, total_len;
308 struct bcm2835_desc *d;
309 struct bcm2835_cb_entry *cb_entry;
310 struct bcm2835_dma_cb *control_block;
315 /* allocate and setup the descriptor. */
316 d = kzalloc(struct_size(d, cb_list, frames), gfp);
325 * Iterate over all frames, create a control block
326 * for each frame and link them together.
328 for (frame = 0, total_len = 0; frame < frames; d->frames++, frame++) {
329 cb_entry = &d->cb_list[frame];
330 cb_entry->cb = dma_pool_alloc(c->cb_pool, gfp,
335 /* fill in the control block */
336 control_block = cb_entry->cb;
337 control_block->info = info;
338 control_block->src = src;
339 control_block->dst = dst;
340 control_block->stride = 0;
341 control_block->next = 0;
342 /* set up length in control_block if requested */
344 /* calculate length honoring period_length */
345 bcm2835_dma_create_cb_set_length(
347 len, period_len, &total_len,
348 cyclic ? finalextrainfo : 0);
350 /* calculate new remaining length */
351 len -= control_block->length;
354 /* link this the last controlblock */
356 d->cb_list[frame - 1].cb->next = cb_entry->paddr;
358 /* update src and dst and length */
359 if (src && (info & BCM2835_DMA_S_INC))
360 src += control_block->length;
361 if (dst && (info & BCM2835_DMA_D_INC))
362 dst += control_block->length;
364 /* Length of total transfer */
365 d->size += control_block->length;
368 /* the last frame requires extra flags */
369 d->cb_list[d->frames - 1].cb->info |= finalextrainfo;
371 /* detect a size missmatch */
372 if (buf_len && (d->size != buf_len))
377 bcm2835_dma_free_cb_chain(d);
382 static void bcm2835_dma_fill_cb_chain_with_sg(
383 struct dma_chan *chan,
384 enum dma_transfer_direction direction,
385 struct bcm2835_cb_entry *cb,
386 struct scatterlist *sgl,
389 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
393 struct scatterlist *sgent;
395 max_len = bcm2835_dma_max_frame_length(c);
396 for_each_sg(sgl, sgent, sg_len, i) {
397 for (addr = sg_dma_address(sgent), len = sg_dma_len(sgent);
399 addr += cb->cb->length, len -= cb->cb->length, cb++) {
400 if (direction == DMA_DEV_TO_MEM)
404 cb->cb->length = min(len, max_len);
409 static void bcm2835_dma_abort(struct bcm2835_chan *c)
411 void __iomem *chan_base = c->chan_base;
412 long int timeout = 10000;
415 * A zero control block address means the channel is idle.
416 * (The ACTIVE flag in the CS register is not a reliable indicator.)
418 if (!readl(chan_base + BCM2835_DMA_ADDR))
421 /* Write 0 to the active bit - Pause the DMA */
422 writel(0, chan_base + BCM2835_DMA_CS);
424 /* Wait for any current AXI transfer to complete */
425 while ((readl(chan_base + BCM2835_DMA_CS) &
426 BCM2835_DMA_WAITING_FOR_WRITES) && --timeout)
429 /* Peripheral might be stuck and fail to signal AXI write responses */
431 dev_err(c->vc.chan.device->dev,
432 "failed to complete outstanding writes\n");
434 writel(BCM2835_DMA_RESET, chan_base + BCM2835_DMA_CS);
437 static void bcm2835_dma_start_desc(struct bcm2835_chan *c)
439 struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
440 struct bcm2835_desc *d;
449 c->desc = d = to_bcm2835_dma_desc(&vd->tx);
451 writel(d->cb_list[0].paddr, c->chan_base + BCM2835_DMA_ADDR);
452 writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS);
455 static irqreturn_t bcm2835_dma_callback(int irq, void *data)
457 struct bcm2835_chan *c = data;
458 struct bcm2835_desc *d;
461 /* check the shared interrupt */
462 if (c->irq_flags & IRQF_SHARED) {
463 /* check if the interrupt is enabled */
464 flags = readl(c->chan_base + BCM2835_DMA_CS);
465 /* if not set then we are not the reason for the irq */
466 if (!(flags & BCM2835_DMA_INT))
470 spin_lock_irqsave(&c->vc.lock, flags);
473 * Clear the INT flag to receive further interrupts. Keep the channel
474 * active in case the descriptor is cyclic or in case the client has
475 * already terminated the descriptor and issued a new one. (May happen
476 * if this IRQ handler is threaded.) If the channel is finished, it
477 * will remain idle despite the ACTIVE flag being set.
479 writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE,
480 c->chan_base + BCM2835_DMA_CS);
486 /* call the cyclic callback */
487 vchan_cyclic_callback(&d->vd);
488 } else if (!readl(c->chan_base + BCM2835_DMA_ADDR)) {
489 vchan_cookie_complete(&c->desc->vd);
490 bcm2835_dma_start_desc(c);
494 spin_unlock_irqrestore(&c->vc.lock, flags);
499 static int bcm2835_dma_alloc_chan_resources(struct dma_chan *chan)
501 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
502 struct device *dev = c->vc.chan.device->dev;
504 dev_dbg(dev, "Allocating DMA channel %d\n", c->ch);
507 * Control blocks are 256 bit in length and must start at a 256 bit
508 * (32 byte) aligned address (BCM2835 ARM Peripherals, sec. 4.2.1.1).
510 c->cb_pool = dma_pool_create(dev_name(dev), dev,
511 sizeof(struct bcm2835_dma_cb), 32, 0);
513 dev_err(dev, "unable to allocate descriptor pool\n");
517 return request_irq(c->irq_number, bcm2835_dma_callback,
518 c->irq_flags, "DMA IRQ", c);
521 static void bcm2835_dma_free_chan_resources(struct dma_chan *chan)
523 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
525 vchan_free_chan_resources(&c->vc);
526 free_irq(c->irq_number, c);
527 dma_pool_destroy(c->cb_pool);
529 dev_dbg(c->vc.chan.device->dev, "Freeing DMA channel %u\n", c->ch);
532 static size_t bcm2835_dma_desc_size(struct bcm2835_desc *d)
537 static size_t bcm2835_dma_desc_size_pos(struct bcm2835_desc *d, dma_addr_t addr)
542 for (size = i = 0; i < d->frames; i++) {
543 struct bcm2835_dma_cb *control_block = d->cb_list[i].cb;
544 size_t this_size = control_block->length;
547 if (d->dir == DMA_DEV_TO_MEM)
548 dma = control_block->dst;
550 dma = control_block->src;
554 else if (addr >= dma && addr < dma + this_size)
555 size += dma + this_size - addr;
561 static enum dma_status bcm2835_dma_tx_status(struct dma_chan *chan,
562 dma_cookie_t cookie, struct dma_tx_state *txstate)
564 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
565 struct virt_dma_desc *vd;
569 ret = dma_cookie_status(chan, cookie, txstate);
570 if (ret == DMA_COMPLETE || !txstate)
573 spin_lock_irqsave(&c->vc.lock, flags);
574 vd = vchan_find_desc(&c->vc, cookie);
577 bcm2835_dma_desc_size(to_bcm2835_dma_desc(&vd->tx));
578 } else if (c->desc && c->desc->vd.tx.cookie == cookie) {
579 struct bcm2835_desc *d = c->desc;
582 if (d->dir == DMA_MEM_TO_DEV)
583 pos = readl(c->chan_base + BCM2835_DMA_SOURCE_AD);
584 else if (d->dir == DMA_DEV_TO_MEM)
585 pos = readl(c->chan_base + BCM2835_DMA_DEST_AD);
589 txstate->residue = bcm2835_dma_desc_size_pos(d, pos);
591 txstate->residue = 0;
594 spin_unlock_irqrestore(&c->vc.lock, flags);
599 static void bcm2835_dma_issue_pending(struct dma_chan *chan)
601 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
604 spin_lock_irqsave(&c->vc.lock, flags);
605 if (vchan_issue_pending(&c->vc) && !c->desc)
606 bcm2835_dma_start_desc(c);
608 spin_unlock_irqrestore(&c->vc.lock, flags);
611 static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_memcpy(
612 struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
613 size_t len, unsigned long flags)
615 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
616 struct bcm2835_desc *d;
617 u32 info = BCM2835_DMA_D_INC | BCM2835_DMA_S_INC;
618 u32 extra = BCM2835_DMA_INT_EN | BCM2835_DMA_WAIT_RESP;
619 size_t max_len = bcm2835_dma_max_frame_length(c);
622 /* if src, dst or len is not given return with an error */
623 if (!src || !dst || !len)
626 /* calculate number of frames */
627 frames = bcm2835_dma_frames_for_length(len, max_len);
629 /* allocate the CB chain - this also fills in the pointers */
630 d = bcm2835_dma_create_cb_chain(chan, DMA_MEM_TO_MEM, false,
632 src, dst, len, 0, GFP_KERNEL);
636 return vchan_tx_prep(&c->vc, &d->vd, flags);
639 static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
640 struct dma_chan *chan,
641 struct scatterlist *sgl, unsigned int sg_len,
642 enum dma_transfer_direction direction,
643 unsigned long flags, void *context)
645 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
646 struct bcm2835_desc *d;
647 dma_addr_t src = 0, dst = 0;
648 u32 info = BCM2835_DMA_WAIT_RESP;
649 u32 extra = BCM2835_DMA_INT_EN;
652 if (!is_slave_direction(direction)) {
653 dev_err(chan->device->dev,
654 "%s: bad direction?\n", __func__);
659 info |= BCM2835_DMA_PER_MAP(c->dreq);
661 if (direction == DMA_DEV_TO_MEM) {
662 if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
664 src = c->cfg.src_addr;
665 info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
667 if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
669 dst = c->cfg.dst_addr;
670 info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
673 /* count frames in sg list */
674 frames = bcm2835_dma_count_frames_for_sg(c, sgl, sg_len);
676 /* allocate the CB chain */
677 d = bcm2835_dma_create_cb_chain(chan, direction, false,
679 frames, src, dst, 0, 0,
684 /* fill in frames with scatterlist pointers */
685 bcm2835_dma_fill_cb_chain_with_sg(chan, direction, d->cb_list,
688 return vchan_tx_prep(&c->vc, &d->vd, flags);
691 static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
692 struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
693 size_t period_len, enum dma_transfer_direction direction,
696 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
697 struct bcm2835_desc *d;
699 u32 info = BCM2835_DMA_WAIT_RESP;
701 size_t max_len = bcm2835_dma_max_frame_length(c);
704 /* Grab configuration */
705 if (!is_slave_direction(direction)) {
706 dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
711 dev_err(chan->device->dev,
712 "%s: bad buffer length (= 0)\n", __func__);
716 if (flags & DMA_PREP_INTERRUPT)
717 extra |= BCM2835_DMA_INT_EN;
719 period_len = buf_len;
722 * warn if buf_len is not a multiple of period_len - this may leed
723 * to unexpected latencies for interrupts and thus audiable clicks
725 if (buf_len % period_len)
726 dev_warn_once(chan->device->dev,
727 "%s: buffer_length (%zd) is not a multiple of period_len (%zd)\n",
728 __func__, buf_len, period_len);
730 /* Setup DREQ channel */
732 info |= BCM2835_DMA_PER_MAP(c->dreq);
734 if (direction == DMA_DEV_TO_MEM) {
735 if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
737 src = c->cfg.src_addr;
739 info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
741 if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
743 dst = c->cfg.dst_addr;
745 info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
748 /* calculate number of frames */
749 frames = /* number of periods */
750 DIV_ROUND_UP(buf_len, period_len) *
751 /* number of frames per period */
752 bcm2835_dma_frames_for_length(period_len, max_len);
755 * allocate the CB chain
756 * note that we need to use GFP_NOWAIT, as the ALSA i2s dmaengine
757 * implementation calls prep_dma_cyclic with interrupts disabled.
759 d = bcm2835_dma_create_cb_chain(chan, direction, true,
761 frames, src, dst, buf_len,
762 period_len, GFP_NOWAIT);
766 /* wrap around into a loop */
767 d->cb_list[d->frames - 1].cb->next = d->cb_list[0].paddr;
769 return vchan_tx_prep(&c->vc, &d->vd, flags);
772 static int bcm2835_dma_slave_config(struct dma_chan *chan,
773 struct dma_slave_config *cfg)
775 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
782 static int bcm2835_dma_terminate_all(struct dma_chan *chan)
784 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
788 spin_lock_irqsave(&c->vc.lock, flags);
790 /* stop DMA activity */
792 if (c->desc->vd.tx.flags & DMA_PREP_INTERRUPT)
793 vchan_terminate_vdesc(&c->desc->vd);
795 vchan_vdesc_fini(&c->desc->vd);
797 bcm2835_dma_abort(c);
800 vchan_get_all_descriptors(&c->vc, &head);
801 spin_unlock_irqrestore(&c->vc.lock, flags);
802 vchan_dma_desc_free_list(&c->vc, &head);
807 static void bcm2835_dma_synchronize(struct dma_chan *chan)
809 struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
811 vchan_synchronize(&c->vc);
814 static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,
815 int irq, unsigned int irq_flags)
817 struct bcm2835_chan *c;
819 c = devm_kzalloc(d->ddev.dev, sizeof(*c), GFP_KERNEL);
823 c->vc.desc_free = bcm2835_dma_desc_free;
824 vchan_init(&c->vc, &d->ddev);
826 c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id);
829 c->irq_flags = irq_flags;
831 /* check in DEBUG register if this is a LITE channel */
832 if (readl(c->chan_base + BCM2835_DMA_DEBUG) &
833 BCM2835_DMA_DEBUG_LITE)
834 c->is_lite_channel = true;
839 static void bcm2835_dma_free(struct bcm2835_dmadev *od)
841 struct bcm2835_chan *c, *next;
843 list_for_each_entry_safe(c, next, &od->ddev.channels,
844 vc.chan.device_node) {
845 list_del(&c->vc.chan.device_node);
846 tasklet_kill(&c->vc.task);
850 static const struct of_device_id bcm2835_dma_of_match[] = {
851 { .compatible = "brcm,bcm2835-dma", },
854 MODULE_DEVICE_TABLE(of, bcm2835_dma_of_match);
856 static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec,
857 struct of_dma *ofdma)
859 struct bcm2835_dmadev *d = ofdma->of_dma_data;
860 struct dma_chan *chan;
862 chan = dma_get_any_slave_channel(&d->ddev);
866 /* Set DREQ from param */
867 to_bcm2835_dma_chan(chan)->dreq = spec->args[0];
872 static int bcm2835_dma_probe(struct platform_device *pdev)
874 struct bcm2835_dmadev *od;
875 struct resource *res;
879 int irq[BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED + 1];
881 uint32_t chans_available;
882 char chan_name[BCM2835_DMA_CHAN_NAME_SIZE];
884 if (!pdev->dev.dma_mask)
885 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
887 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
891 od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL);
895 pdev->dev.dma_parms = &od->dma_parms;
896 dma_set_max_seg_size(&pdev->dev, 0x3FFFFFFF);
898 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
899 base = devm_ioremap_resource(&pdev->dev, res);
901 return PTR_ERR(base);
905 dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
906 dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask);
907 dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
908 dma_cap_set(DMA_MEMCPY, od->ddev.cap_mask);
909 od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources;
910 od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources;
911 od->ddev.device_tx_status = bcm2835_dma_tx_status;
912 od->ddev.device_issue_pending = bcm2835_dma_issue_pending;
913 od->ddev.device_prep_dma_cyclic = bcm2835_dma_prep_dma_cyclic;
914 od->ddev.device_prep_slave_sg = bcm2835_dma_prep_slave_sg;
915 od->ddev.device_prep_dma_memcpy = bcm2835_dma_prep_dma_memcpy;
916 od->ddev.device_config = bcm2835_dma_slave_config;
917 od->ddev.device_terminate_all = bcm2835_dma_terminate_all;
918 od->ddev.device_synchronize = bcm2835_dma_synchronize;
919 od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
920 od->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
921 od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
923 od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
924 od->ddev.descriptor_reuse = true;
925 od->ddev.dev = &pdev->dev;
926 INIT_LIST_HEAD(&od->ddev.channels);
928 platform_set_drvdata(pdev, od);
930 /* Request DMA channel mask from device tree */
931 if (of_property_read_u32(pdev->dev.of_node,
932 "brcm,dma-channel-mask",
934 dev_err(&pdev->dev, "Failed to get channel mask\n");
939 /* get irqs for each channel that we support */
940 for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
941 /* skip masked out channels */
942 if (!(chans_available & (1 << i))) {
947 /* get the named irq */
948 snprintf(chan_name, sizeof(chan_name), "dma%i", i);
949 irq[i] = platform_get_irq_byname(pdev, chan_name);
953 /* legacy device tree case handling */
954 dev_warn_once(&pdev->dev,
955 "missing interrupt-names property in device tree - legacy interpretation is used\n");
957 * in case of channel >= 11
958 * use the 11th interrupt and that is shared
960 irq[i] = platform_get_irq(pdev, i < 11 ? i : 11);
963 /* get irqs for each channel */
964 for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
965 /* skip channels without irq */
969 /* check if there are other channels that also use this irq */
971 for (j = 0; j <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; j++)
972 if ((i != j) && (irq[j] == irq[i])) {
973 irq_flags = IRQF_SHARED;
977 /* initialize the channel */
978 rc = bcm2835_dma_chan_init(od, i, irq[i], irq_flags);
983 dev_dbg(&pdev->dev, "Initialized %i DMA channels\n", i);
985 /* Device-tree DMA controller registration */
986 rc = of_dma_controller_register(pdev->dev.of_node,
987 bcm2835_dma_xlate, od);
989 dev_err(&pdev->dev, "Failed to register DMA controller\n");
993 rc = dma_async_device_register(&od->ddev);
996 "Failed to register slave DMA engine device: %d\n", rc);
1000 dev_dbg(&pdev->dev, "Load BCM2835 DMA engine driver\n");
1005 bcm2835_dma_free(od);
1009 static int bcm2835_dma_remove(struct platform_device *pdev)
1011 struct bcm2835_dmadev *od = platform_get_drvdata(pdev);
1013 dma_async_device_unregister(&od->ddev);
1014 bcm2835_dma_free(od);
1019 static struct platform_driver bcm2835_dma_driver = {
1020 .probe = bcm2835_dma_probe,
1021 .remove = bcm2835_dma_remove,
1023 .name = "bcm2835-dma",
1024 .of_match_table = of_match_ptr(bcm2835_dma_of_match),
1028 module_platform_driver(bcm2835_dma_driver);
1030 MODULE_ALIAS("platform:bcm2835-dma");
1031 MODULE_DESCRIPTION("BCM2835 DMA engine driver");
1032 MODULE_AUTHOR("Florian Meier <florian.meier@koalo.de>");
1033 MODULE_LICENSE("GPL");