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         void *page = NULL;
 147
 148         if (channel->type == EVTCHNL_TYPE_REQ)
 149                 page = channel->u.req.ring.sring;
 150         else if (channel->type == EVTCHNL_TYPE_EVT)
 151                 page = 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         xenbus_teardown_ring(&page, 1, &channel->gref);
 171
 172         memset(channel, 0, sizeof(*channel));
 173 }
 174
 175 void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info)
 176 {
 177         int i;
 178
 179         if (!front_info->evt_pairs)
 180                 return;
 181
 182         for (i = 0; i < front_info->num_evt_pairs; i++) {
 183                 evtchnl_free(front_info, &front_info->evt_pairs[i].req);
 184                 evtchnl_free(front_info, &front_info->evt_pairs[i].evt);
 185         }
 186
 187         kfree(front_info->evt_pairs);
 188         front_info->evt_pairs = NULL;
 189 }
 190
 191 static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
 192                          struct xen_snd_front_evtchnl *channel,
 193                          enum xen_snd_front_evtchnl_type type)
 194 {
 195         struct xenbus_device *xb_dev = front_info->xb_dev;
 196         void *page;
 197         irq_handler_t handler;
 198         char *handler_name = NULL;
 199         int ret;
 200
 201         memset(channel, 0, sizeof(*channel));
 202         channel->type = type;
 203         channel->index = index;
 204         channel->front_info = front_info;
 205         channel->state = EVTCHNL_STATE_DISCONNECTED;
 206         ret = xenbus_setup_ring(xb_dev, GFP_KERNEL, &page, 1, &channel->gref);
 207         if (ret)
 208                 goto fail;
 209
 210         handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,
 211                                  type == EVTCHNL_TYPE_REQ ?
 212                                  XENSND_FIELD_RING_REF :
 213                                  XENSND_FIELD_EVT_RING_REF);
 214         if (!handler_name) {
 215                 ret = -ENOMEM;
 216                 goto fail;
 217         }
 218
 219         mutex_init(&channel->ring_io_lock);
 220
 221         if (type == EVTCHNL_TYPE_REQ) {
 222                 struct xen_sndif_sring *sring = page;
 223
 224                 init_completion(&channel->u.req.completion);
 225                 mutex_init(&channel->u.req.req_io_lock);
 226                 XEN_FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);
 227
 228                 handler = evtchnl_interrupt_req;
 229         } else {
 230                 channel->u.evt.page = page;
 231                 handler = evtchnl_interrupt_evt;
 232         }
 233
 234         ret = xenbus_alloc_evtchn(xb_dev, &channel->port);
 235         if (ret < 0)
 236                 goto fail;
 237
 238         ret = bind_evtchn_to_irq(channel->port);
 239         if (ret < 0) {
 240                 dev_err(&xb_dev->dev,
 241                         "Failed to bind IRQ for domid %d port %d: %d\n",
 242                         front_info->xb_dev->otherend_id, channel->port, ret);
 243                 goto fail;
 244         }
 245
 246         channel->irq = ret;
 247
 248         ret = request_threaded_irq(channel->irq, NULL, handler,
 249                                    IRQF_ONESHOT, handler_name, channel);
 250         if (ret < 0) {
 251                 dev_err(&xb_dev->dev, "Failed to request IRQ %d: %d\n",
 252                         channel->irq, ret);
 253                 goto fail;
 254         }
 255
 256         kfree(handler_name);
 257         return 0;
 258
 259 fail:
 260         kfree(handler_name);
 261         dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret);
 262         return ret;
 263 }
 264
 265 int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
 266                                      int num_streams)
 267 {
 268         struct xen_front_cfg_card *cfg = &front_info->cfg;
 269         struct device *dev = &front_info->xb_dev->dev;
 270         int d, ret = 0;
 271
 272         front_info->evt_pairs =
 273                         kcalloc(num_streams,
 274                                 sizeof(struct xen_snd_front_evtchnl_pair),
 275                                 GFP_KERNEL);
 276         if (!front_info->evt_pairs)
 277                 return -ENOMEM;
 278
 279         /* Iterate over devices and their streams and create event channels. */
 280         for (d = 0; d < cfg->num_pcm_instances; d++) {
 281                 struct xen_front_cfg_pcm_instance *pcm_instance;
 282                 int s, index;
 283
 284                 pcm_instance = &cfg->pcm_instances[d];
 285
 286                 for (s = 0; s < pcm_instance->num_streams_pb; s++) {
 287                         index = pcm_instance->streams_pb[s].index;
 288
 289                         ret = evtchnl_alloc(front_info, index,
 290                                             &front_info->evt_pairs[index].req,
 291                                             EVTCHNL_TYPE_REQ);
 292                         if (ret < 0) {
 293                                 dev_err(dev, "Error allocating control channel\n");
 294                                 goto fail;
 295                         }
 296
 297                         ret = evtchnl_alloc(front_info, index,
 298                                             &front_info->evt_pairs[index].evt,
 299                                             EVTCHNL_TYPE_EVT);
 300                         if (ret < 0) {
 301                                 dev_err(dev, "Error allocating in-event channel\n");
 302                                 goto fail;
 303                         }
 304                 }
 305
 306                 for (s = 0; s < pcm_instance->num_streams_cap; s++) {
 307                         index = pcm_instance->streams_cap[s].index;
 308
 309                         ret = evtchnl_alloc(front_info, index,
 310                                             &front_info->evt_pairs[index].req,
 311                                             EVTCHNL_TYPE_REQ);
 312                         if (ret < 0) {
 313                                 dev_err(dev, "Error allocating control channel\n");
 314                                 goto fail;
 315                         }
 316
 317                         ret = evtchnl_alloc(front_info, index,
 318                                             &front_info->evt_pairs[index].evt,
 319                                             EVTCHNL_TYPE_EVT);
 320                         if (ret < 0) {
 321                                 dev_err(dev, "Error allocating in-event channel\n");
 322                                 goto fail;
 323                         }
 324                 }
 325         }
 326
 327         front_info->num_evt_pairs = num_streams;
 328         return 0;
 329
 330 fail:
 331         xen_snd_front_evtchnl_free_all(front_info);
 332         return ret;
 333 }
 334
 335 static int evtchnl_publish(struct xenbus_transaction xbt,
 336                            struct xen_snd_front_evtchnl *channel,
 337                            const char *path, const char *node_ring,
 338                            const char *node_chnl)
 339 {
 340         struct xenbus_device *xb_dev = channel->front_info->xb_dev;
 341         int ret;
 342
 343         /* Write control channel ring reference. */
 344         ret = xenbus_printf(xbt, path, node_ring, "%u", channel->gref);
 345         if (ret < 0) {
 346                 dev_err(&xb_dev->dev, "Error writing ring-ref: %d\n", ret);
 347                 return ret;
 348         }
 349
 350         /* Write event channel ring reference. */
 351         ret = xenbus_printf(xbt, path, node_chnl, "%u", channel->port);
 352         if (ret < 0) {
 353                 dev_err(&xb_dev->dev, "Error writing event channel: %d\n", ret);
 354                 return ret;
 355         }
 356
 357         return 0;
 358 }
 359
 360 int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info)
 361 {
 362         struct xen_front_cfg_card *cfg = &front_info->cfg;
 363         struct xenbus_transaction xbt;
 364         int ret, d;
 365
 366 again:
 367         ret = xenbus_transaction_start(&xbt);
 368         if (ret < 0) {
 369                 xenbus_dev_fatal(front_info->xb_dev, ret,
 370                                  "starting transaction");
 371                 return ret;
 372         }
 373
 374         for (d = 0; d < cfg->num_pcm_instances; d++) {
 375                 struct xen_front_cfg_pcm_instance *pcm_instance;
 376                 int s, index;
 377
 378                 pcm_instance = &cfg->pcm_instances[d];
 379
 380                 for (s = 0; s < pcm_instance->num_streams_pb; s++) {
 381                         index = pcm_instance->streams_pb[s].index;
 382
 383                         ret = evtchnl_publish(xbt,
 384                                               &front_info->evt_pairs[index].req,
 385                                               pcm_instance->streams_pb[s].xenstore_path,
 386                                               XENSND_FIELD_RING_REF,
 387                                               XENSND_FIELD_EVT_CHNL);
 388                         if (ret < 0)
 389                                 goto fail;
 390
 391                         ret = evtchnl_publish(xbt,
 392                                               &front_info->evt_pairs[index].evt,
 393                                               pcm_instance->streams_pb[s].xenstore_path,
 394                                               XENSND_FIELD_EVT_RING_REF,
 395                                               XENSND_FIELD_EVT_EVT_CHNL);
 396                         if (ret < 0)
 397                                 goto fail;
 398                 }
 399
 400                 for (s = 0; s < pcm_instance->num_streams_cap; s++) {
 401                         index = pcm_instance->streams_cap[s].index;
 402
 403                         ret = evtchnl_publish(xbt,
 404                                               &front_info->evt_pairs[index].req,
 405                                               pcm_instance->streams_cap[s].xenstore_path,
 406                                               XENSND_FIELD_RING_REF,
 407                                               XENSND_FIELD_EVT_CHNL);
 408                         if (ret < 0)
 409                                 goto fail;
 410
 411                         ret = evtchnl_publish(xbt,
 412                                               &front_info->evt_pairs[index].evt,
 413                                               pcm_instance->streams_cap[s].xenstore_path,
 414                                               XENSND_FIELD_EVT_RING_REF,
 415                                               XENSND_FIELD_EVT_EVT_CHNL);
 416                         if (ret < 0)
 417                                 goto fail;
 418                 }
 419         }
 420         ret = xenbus_transaction_end(xbt, 0);
 421         if (ret < 0) {
 422                 if (ret == -EAGAIN)
 423                         goto again;
 424
 425                 xenbus_dev_fatal(front_info->xb_dev, ret,
 426                                  "completing transaction");
 427                 goto fail_to_end;
 428         }
 429         return 0;
 430 fail:
 431         xenbus_transaction_end(xbt, 1);
 432 fail_to_end:
 433         xenbus_dev_fatal(front_info->xb_dev, ret, "writing XenStore");
 434         return ret;
 435 }
 436
 437 void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
 438                                               bool is_connected)
 439 {
 440         enum xen_snd_front_evtchnl_state state;
 441
 442         if (is_connected)
 443                 state = EVTCHNL_STATE_CONNECTED;
 444         else
 445                 state = EVTCHNL_STATE_DISCONNECTED;
 446
 447         mutex_lock(&evt_pair->req.ring_io_lock);
 448         evt_pair->req.state = state;
 449         mutex_unlock(&evt_pair->req.ring_io_lock);
 450
 451         mutex_lock(&evt_pair->evt.ring_io_lock);
 452         evt_pair->evt.state = state;
 453         mutex_unlock(&evt_pair->evt.ring_io_lock);
 454 }
 455
 456 void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair)
 457 {
 458         mutex_lock(&evt_pair->req.ring_io_lock);
 459         evt_pair->req.evt_next_id = 0;
 460         mutex_unlock(&evt_pair->req.ring_io_lock);
 461
 462         mutex_lock(&evt_pair->evt.ring_io_lock);
 463         evt_pair->evt.evt_next_id = 0;
 464         mutex_unlock(&evt_pair->evt.ring_io_lock);
 465 }
 466