sound/xen/xen_snd_front_evtchnl.c

   1 // SPDX-License-Identifier: GPL-2.0 OR MIT
   2
   3 /*
   4  * Xen para-virtual sound device
   5  *
   6  * Copyright (C) 2016-2018 EPAM Systems Inc.
   7  *
   8  * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
   9  */
  10
  11 #include <xen/events.h>
  12 #include <xen/grant_table.h>
  13 #include <xen/xen.h>
  14 #include <xen/xenbus.h>
  15
  16 #include "xen_snd_front.h"
  17 #include "xen_snd_front_alsa.h"
  18 #include "xen_snd_front_cfg.h"
  19 #include "xen_snd_front_evtchnl.h"
  20
  21 static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id)
  22 {
  23         struct xen_snd_front_evtchnl *channel = dev_id;
  24         struct xen_snd_front_info *front_info = channel->front_info;
  25         struct xensnd_resp *resp;
  26         RING_IDX i, rp;
  27
  28         if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
  29                 return IRQ_HANDLED;
  30
  31         mutex_lock(&channel->ring_io_lock);
  32
  33 again:
  34         rp = channel->u.req.ring.sring->rsp_prod;
  35         /* Ensure we see queued responses up to rp. */
  36         rmb();
  37
  38         /*
  39          * Assume that the backend is trusted to always write sane values
  40          * to the ring counters, so no overflow checks on frontend side
  41          * are required.
  42          */
  43         for (i = channel->u.req.ring.rsp_cons; i != rp; i++) {
  44                 resp = RING_GET_RESPONSE(&channel->u.req.ring, i);
  45                 if (resp->id != channel->evt_id)
  46                         continue;
  47                 switch (resp->operation) {
  48                 case XENSND_OP_OPEN:
  49                 case XENSND_OP_CLOSE:
  50                 case XENSND_OP_READ:
  51                 case XENSND_OP_WRITE:
  52                 case XENSND_OP_TRIGGER:
  53                         channel->u.req.resp_status = resp->status;
  54                         complete(&channel->u.req.completion);
  55                         break;
  56                 case XENSND_OP_HW_PARAM_QUERY:
  57                         channel->u.req.resp_status = resp->status;
  58                         channel->u.req.resp.hw_param =
  59                                         resp->resp.hw_param;
  60                         complete(&channel->u.req.completion);
  61                         break;
  62
  63                 default:
  64                         dev_err(&front_info->xb_dev->dev,
  65                                 "Operation %d is not supported\n",
  66                                 resp->operation);
  67                         break;
  68                 }
  69         }
  70
  71         channel->u.req.ring.rsp_cons = i;
  72         if (i != channel->u.req.ring.req_prod_pvt) {
  73                 int more_to_do;
  74
  75                 RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring,
  76                                                more_to_do);
  77                 if (more_to_do)
  78                         goto again;
  79         } else {
  80                 channel->u.req.ring.sring->rsp_event = i + 1;
  81         }
  82
  83         mutex_unlock(&channel->ring_io_lock);
  84         return IRQ_HANDLED;
  85 }
  86
  87 static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id)
  88 {
  89         struct xen_snd_front_evtchnl *channel = dev_id;
  90         struct xensnd_event_page *page = channel->u.evt.page;
  91         u32 cons, prod;
  92
  93         if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
  94                 return IRQ_HANDLED;
  95
  96         mutex_lock(&channel->ring_io_lock);
  97
  98         prod = page->in_prod;
  99         /* Ensure we see ring contents up to prod. */
 100         virt_rmb();
 101         if (prod == page->in_cons)
 102                 goto out;
 103
 104         /*
 105          * Assume that the backend is trusted to always write sane values
 106          * to the ring counters, so no overflow checks on frontend side
 107          * are required.
 108          */
 109         for (cons = page->in_cons; cons != prod; cons++) {
 110                 struct xensnd_evt *event;
 111
 112                 event = &XENSND_IN_RING_REF(page, cons);
 113                 if (unlikely(event->id != channel->evt_id++))
 114                         continue;
 115
 116                 switch (event->type) {
 117                 case XENSND_EVT_CUR_POS:
 118                         xen_snd_front_alsa_handle_cur_pos(channel,
 119                                                           event->op.cur_pos.position);
 120                         break;
 121                 }
 122         }
 123
 124         page->in_cons = cons;
 125         /* Ensure ring contents. */
 126         virt_wmb();
 127
 128 out:
 129         mutex_unlock(&channel->ring_io_lock);
 130         return IRQ_HANDLED;
 131 }
 132
 133 void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel)
 134 {
 135         int notify;
 136
 137         channel->u.req.ring.req_prod_pvt++;
 138         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify);
 139         if (notify)
 140                 notify_remote_via_irq(channel->irq);
 141 }
 142
 143 static void evtchnl_free(struct xen_snd_front_info *front_info,
 144                          struct xen_snd_front_evtchnl *channel)
 145 {
 146         unsigned long page = 0;
 147
 148         if (channel->type == EVTCHNL_TYPE_REQ)
 149                 page = (unsigned long)channel->u.req.ring.sring;
 150         else if (channel->type == EVTCHNL_TYPE_EVT)
 151                 page = (unsigned long)channel->u.evt.page;
 152
 153         if (!page)
 154                 return;
 155
 156         channel->state = EVTCHNL_STATE_DISCONNECTED;
 157         if (channel->type == EVTCHNL_TYPE_REQ) {
 158                 /* Release all who still waits for response if any. */
 159                 channel->u.req.resp_status = -EIO;
 160                 complete_all(&channel->u.req.completion);
 161         }
 162
 163         if (channel->irq)
 164                 unbind_from_irqhandler(channel->irq, channel);
 165
 166         if (channel->port)
 167                 xenbus_free_evtchn(front_info->xb_dev, channel->port);
 168
 169         /* End access and free the page. */
 170         if (channel->gref != GRANT_INVALID_REF)
 171                 gnttab_end_foreign_access(channel->gref, 0, page);
 172         else
 173                 free_page(page);
 174
 175         memset(channel, 0, sizeof(*channel));
 176 }
 177
 178 void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info)
 179 {
 180         int i;
 181
 182         if (!front_info->evt_pairs)
 183                 return;
 184
 185         for (i = 0; i < front_info->num_evt_pairs; i++) {
 186                 evtchnl_free(front_info, &front_info->evt_pairs[i].req);
 187                 evtchnl_free(front_info, &front_info->evt_pairs[i].evt);
 188         }
 189
 190         kfree(front_info->evt_pairs);
 191         front_info->evt_pairs = NULL;
 192 }
 193
 194 static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
 195                          struct xen_snd_front_evtchnl *channel,
 196                          enum xen_snd_front_evtchnl_type type)
 197 {
 198         struct xenbus_device *xb_dev = front_info->xb_dev;
 199         unsigned long page;
 200         grant_ref_t gref;
 201         irq_handler_t handler;
 202         char *handler_name = NULL;
 203         int ret;
 204
 205         memset(channel, 0, sizeof(*channel));
 206         channel->type = type;
 207         channel->index = index;
 208         channel->front_info = front_info;
 209         channel->state = EVTCHNL_STATE_DISCONNECTED;
 210         channel->gref = GRANT_INVALID_REF;
 211         page = get_zeroed_page(GFP_KERNEL);
 212         if (!page) {
 213                 ret = -ENOMEM;
 214                 goto fail;
 215         }
 216
 217         handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,
 218                                  type == EVTCHNL_TYPE_REQ ?
 219                                  XENSND_FIELD_RING_REF :
 220                                  XENSND_FIELD_EVT_RING_REF);
 221         if (!handler_name) {
 222                 ret = -ENOMEM;
 223                 goto fail;
 224         }
 225
 226         mutex_init(&channel->ring_io_lock);
 227
 228         if (type == EVTCHNL_TYPE_REQ) {
 229                 struct xen_sndif_sring *sring = (struct xen_sndif_sring *)page;
 230
 231                 init_completion(&channel->u.req.completion);
 232                 mutex_init(&channel->u.req.req_io_lock);
 233                 SHARED_RING_INIT(sring);
 234                 FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);
 235
 236                 ret = xenbus_grant_ring(xb_dev, sring, 1, &gref);
 237                 if (ret < 0) {
 238                         channel->u.req.ring.sring = NULL;
 239                         goto fail;
 240                 }
 241
 242                 handler = evtchnl_interrupt_req;
 243         } else {
 244                 ret = gnttab_grant_foreign_access(xb_dev->otherend_id,
 245                                                   virt_to_gfn((void *)page), 0);
 246                 if (ret < 0)
 247                         goto fail;
 248
 249                 channel->u.evt.page = (struct xensnd_event_page *)page;
 250                 gref = ret;
 251                 handler = evtchnl_interrupt_evt;
 252         }
 253
 254         channel->gref = gref;
 255
 256         ret = xenbus_alloc_evtchn(xb_dev, &channel->port);
 257         if (ret < 0)
 258                 goto fail;
 259
 260         ret = bind_evtchn_to_irq(channel->port);
 261         if (ret < 0) {
 262                 dev_err(&xb_dev->dev,
 263                         "Failed to bind IRQ for domid %d port %d: %d\n",
 264                         front_info->xb_dev->otherend_id, channel->port, ret);
 265                 goto fail;
 266         }
 267
 268         channel->irq = ret;
 269
 270         ret = request_threaded_irq(channel->irq, NULL, handler,
 271                                    IRQF_ONESHOT, handler_name, channel);
 272         if (ret < 0) {
 273                 dev_err(&xb_dev->dev, "Failed to request IRQ %d: %d\n",
 274                         channel->irq, ret);
 275                 goto fail;
 276         }
 277
 278         kfree(handler_name);
 279         return 0;
 280
 281 fail:
 282         if (page)
 283                 free_page(page);
 284         kfree(handler_name);
 285         dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret);
 286         return ret;
 287 }
 288
 289 int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
 290                                      int num_streams)
 291 {
 292         struct xen_front_cfg_card *cfg = &front_info->cfg;
 293         struct device *dev = &front_info->xb_dev->dev;
 294         int d, ret = 0;
 295
 296         front_info->evt_pairs =
 297                         kcalloc(num_streams,
 298                                 sizeof(struct xen_snd_front_evtchnl_pair),
 299                                 GFP_KERNEL);
 300         if (!front_info->evt_pairs)
 301                 return -ENOMEM;
 302
 303         /* Iterate over devices and their streams and create event channels. */
 304         for (d = 0; d < cfg->num_pcm_instances; d++) {
 305                 struct xen_front_cfg_pcm_instance *pcm_instance;
 306                 int s, index;
 307
 308                 pcm_instance = &cfg->pcm_instances[d];
 309
 310                 for (s = 0; s < pcm_instance->num_streams_pb; s++) {
 311                         index = pcm_instance->streams_pb[s].index;
 312
 313                         ret = evtchnl_alloc(front_info, index,
 314                                             &front_info->evt_pairs[index].req,
 315                                             EVTCHNL_TYPE_REQ);
 316                         if (ret < 0) {
 317                                 dev_err(dev, "Error allocating control channel\n");
 318                                 goto fail;
 319                         }
 320
 321                         ret = evtchnl_alloc(front_info, index,
 322                                             &front_info->evt_pairs[index].evt,
 323                                             EVTCHNL_TYPE_EVT);
 324                         if (ret < 0) {
 325                                 dev_err(dev, "Error allocating in-event channel\n");
 326                                 goto fail;
 327                         }
 328                 }
 329
 330                 for (s = 0; s < pcm_instance->num_streams_cap; s++) {
 331                         index = pcm_instance->streams_cap[s].index;
 332
 333                         ret = evtchnl_alloc(front_info, index,
 334                                             &front_info->evt_pairs[index].req,
 335                                             EVTCHNL_TYPE_REQ);
 336                         if (ret < 0) {
 337                                 dev_err(dev, "Error allocating control channel\n");
 338                                 goto fail;
 339                         }
 340
 341                         ret = evtchnl_alloc(front_info, index,
 342                                             &front_info->evt_pairs[index].evt,
 343                                             EVTCHNL_TYPE_EVT);
 344                         if (ret < 0) {
 345                                 dev_err(dev, "Error allocating in-event channel\n");
 346                                 goto fail;
 347                         }
 348                 }
 349         }
 350
 351         front_info->num_evt_pairs = num_streams;
 352         return 0;
 353
 354 fail:
 355         xen_snd_front_evtchnl_free_all(front_info);
 356         return ret;
 357 }
 358
 359 static int evtchnl_publish(struct xenbus_transaction xbt,
 360                            struct xen_snd_front_evtchnl *channel,
 361                            const char *path, const char *node_ring,
 362                            const char *node_chnl)
 363 {
 364         struct xenbus_device *xb_dev = channel->front_info->xb_dev;
 365         int ret;
 366
 367         /* Write control channel ring reference. */
 368         ret = xenbus_printf(xbt, path, node_ring, "%u", channel->gref);
 369         if (ret < 0) {
 370                 dev_err(&xb_dev->dev, "Error writing ring-ref: %d\n", ret);
 371                 return ret;
 372         }
 373
 374         /* Write event channel ring reference. */
 375         ret = xenbus_printf(xbt, path, node_chnl, "%u", channel->port);
 376         if (ret < 0) {
 377                 dev_err(&xb_dev->dev, "Error writing event channel: %d\n", ret);
 378                 return ret;
 379         }
 380
 381         return 0;
 382 }
 383
 384 int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info)
 385 {
 386         struct xen_front_cfg_card *cfg = &front_info->cfg;
 387         struct xenbus_transaction xbt;
 388         int ret, d;
 389
 390 again:
 391         ret = xenbus_transaction_start(&xbt);
 392         if (ret < 0) {
 393                 xenbus_dev_fatal(front_info->xb_dev, ret,
 394                                  "starting transaction");
 395                 return ret;
 396         }
 397
 398         for (d = 0; d < cfg->num_pcm_instances; d++) {
 399                 struct xen_front_cfg_pcm_instance *pcm_instance;
 400                 int s, index;
 401
 402                 pcm_instance = &cfg->pcm_instances[d];
 403
 404                 for (s = 0; s < pcm_instance->num_streams_pb; s++) {
 405                         index = pcm_instance->streams_pb[s].index;
 406
 407                         ret = evtchnl_publish(xbt,
 408                                               &front_info->evt_pairs[index].req,
 409                                               pcm_instance->streams_pb[s].xenstore_path,
 410                                               XENSND_FIELD_RING_REF,
 411                                               XENSND_FIELD_EVT_CHNL);
 412                         if (ret < 0)
 413                                 goto fail;
 414
 415                         ret = evtchnl_publish(xbt,
 416                                               &front_info->evt_pairs[index].evt,
 417                                               pcm_instance->streams_pb[s].xenstore_path,
 418                                               XENSND_FIELD_EVT_RING_REF,
 419                                               XENSND_FIELD_EVT_EVT_CHNL);
 420                         if (ret < 0)
 421                                 goto fail;
 422                 }
 423
 424                 for (s = 0; s < pcm_instance->num_streams_cap; s++) {
 425                         index = pcm_instance->streams_cap[s].index;
 426
 427                         ret = evtchnl_publish(xbt,
 428                                               &front_info->evt_pairs[index].req,
 429                                               pcm_instance->streams_cap[s].xenstore_path,
 430                                               XENSND_FIELD_RING_REF,
 431                                               XENSND_FIELD_EVT_CHNL);
 432                         if (ret < 0)
 433                                 goto fail;
 434
 435                         ret = evtchnl_publish(xbt,
 436                                               &front_info->evt_pairs[index].evt,
 437                                               pcm_instance->streams_cap[s].xenstore_path,
 438                                               XENSND_FIELD_EVT_RING_REF,
 439                                               XENSND_FIELD_EVT_EVT_CHNL);
 440                         if (ret < 0)
 441                                 goto fail;
 442                 }
 443         }
 444         ret = xenbus_transaction_end(xbt, 0);
 445         if (ret < 0) {
 446                 if (ret == -EAGAIN)
 447                         goto again;
 448
 449                 xenbus_dev_fatal(front_info->xb_dev, ret,
 450                                  "completing transaction");
 451                 goto fail_to_end;
 452         }
 453         return 0;
 454 fail:
 455         xenbus_transaction_end(xbt, 1);
 456 fail_to_end:
 457         xenbus_dev_fatal(front_info->xb_dev, ret, "writing XenStore");
 458         return ret;
 459 }
 460
 461 void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
 462                                               bool is_connected)
 463 {
 464         enum xen_snd_front_evtchnl_state state;
 465
 466         if (is_connected)
 467                 state = EVTCHNL_STATE_CONNECTED;
 468         else
 469                 state = EVTCHNL_STATE_DISCONNECTED;
 470
 471         mutex_lock(&evt_pair->req.ring_io_lock);
 472         evt_pair->req.state = state;
 473         mutex_unlock(&evt_pair->req.ring_io_lock);
 474
 475         mutex_lock(&evt_pair->evt.ring_io_lock);
 476         evt_pair->evt.state = state;
 477         mutex_unlock(&evt_pair->evt.ring_io_lock);
 478 }
 479
 480 void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair)
 481 {
 482         mutex_lock(&evt_pair->req.ring_io_lock);
 483         evt_pair->req.evt_next_id = 0;
 484         mutex_unlock(&evt_pair->req.ring_io_lock);
 485
 486         mutex_lock(&evt_pair->evt.ring_io_lock);
 487         evt_pair->evt.evt_next_id = 0;
 488         mutex_unlock(&evt_pair->evt.ring_io_lock);
 489 }
 490