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 /* fall through */ 50 case XENSND_OP_CLOSE: 51 /* fall through */ 52 case XENSND_OP_READ: 53 /* fall through */ 54 case XENSND_OP_WRITE: 55 /* fall through */ 56 case XENSND_OP_TRIGGER: 57 channel->u.req.resp_status = resp->status; 58 complete(&channel->u.req.completion); 59 break; 60 case XENSND_OP_HW_PARAM_QUERY: 61 channel->u.req.resp_status = resp->status; 62 channel->u.req.resp.hw_param = 63 resp->resp.hw_param; 64 complete(&channel->u.req.completion); 65 break; 66 67 default: 68 dev_err(&front_info->xb_dev->dev, 69 "Operation %d is not supported\n", 70 resp->operation); 71 break; 72 } 73 } 74 75 channel->u.req.ring.rsp_cons = i; 76 if (i != channel->u.req.ring.req_prod_pvt) { 77 int more_to_do; 78 79 RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring, 80 more_to_do); 81 if (more_to_do) 82 goto again; 83 } else { 84 channel->u.req.ring.sring->rsp_event = i + 1; 85 } 86 87 mutex_unlock(&channel->ring_io_lock); 88 return IRQ_HANDLED; 89 } 90 91 static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id) 92 { 93 struct xen_snd_front_evtchnl *channel = dev_id; 94 struct xensnd_event_page *page = channel->u.evt.page; 95 u32 cons, prod; 96 97 if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED)) 98 return IRQ_HANDLED; 99 100 mutex_lock(&channel->ring_io_lock); 101 102 prod = page->in_prod; 103 /* Ensure we see ring contents up to prod. */ 104 virt_rmb(); 105 if (prod == page->in_cons) 106 goto out; 107 108 /* 109 * Assume that the backend is trusted to always write sane values 110 * to the ring counters, so no overflow checks on frontend side 111 * are required. 112 */ 113 for (cons = page->in_cons; cons != prod; cons++) { 114 struct xensnd_evt *event; 115 116 event = &XENSND_IN_RING_REF(page, cons); 117 if (unlikely(event->id != channel->evt_id++)) 118 continue; 119 120 switch (event->type) { 121 case XENSND_EVT_CUR_POS: 122 xen_snd_front_alsa_handle_cur_pos(channel, 123 event->op.cur_pos.position); 124 break; 125 } 126 } 127 128 page->in_cons = cons; 129 /* Ensure ring contents. */ 130 virt_wmb(); 131 132 out: 133 mutex_unlock(&channel->ring_io_lock); 134 return IRQ_HANDLED; 135 } 136 137 void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel) 138 { 139 int notify; 140 141 channel->u.req.ring.req_prod_pvt++; 142 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify); 143 if (notify) 144 notify_remote_via_irq(channel->irq); 145 } 146 147 static void evtchnl_free(struct xen_snd_front_info *front_info, 148 struct xen_snd_front_evtchnl *channel) 149 { 150 unsigned long page = 0; 151 152 if (channel->type == EVTCHNL_TYPE_REQ) 153 page = (unsigned long)channel->u.req.ring.sring; 154 else if (channel->type == EVTCHNL_TYPE_EVT) 155 page = (unsigned long)channel->u.evt.page; 156 157 if (!page) 158 return; 159 160 channel->state = EVTCHNL_STATE_DISCONNECTED; 161 if (channel->type == EVTCHNL_TYPE_REQ) { 162 /* Release all who still waits for response if any. */ 163 channel->u.req.resp_status = -EIO; 164 complete_all(&channel->u.req.completion); 165 } 166 167 if (channel->irq) 168 unbind_from_irqhandler(channel->irq, channel); 169 170 if (channel->port) 171 xenbus_free_evtchn(front_info->xb_dev, channel->port); 172 173 /* End access and free the page. */ 174 if (channel->gref != GRANT_INVALID_REF) 175 gnttab_end_foreign_access(channel->gref, 0, page); 176 else 177 free_page(page); 178 179 memset(channel, 0, sizeof(*channel)); 180 } 181 182 void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info) 183 { 184 int i; 185 186 if (!front_info->evt_pairs) 187 return; 188 189 for (i = 0; i < front_info->num_evt_pairs; i++) { 190 evtchnl_free(front_info, &front_info->evt_pairs[i].req); 191 evtchnl_free(front_info, &front_info->evt_pairs[i].evt); 192 } 193 194 kfree(front_info->evt_pairs); 195 front_info->evt_pairs = NULL; 196 } 197 198 static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index, 199 struct xen_snd_front_evtchnl *channel, 200 enum xen_snd_front_evtchnl_type type) 201 { 202 struct xenbus_device *xb_dev = front_info->xb_dev; 203 unsigned long page; 204 grant_ref_t gref; 205 irq_handler_t handler; 206 char *handler_name = NULL; 207 int ret; 208 209 memset(channel, 0, sizeof(*channel)); 210 channel->type = type; 211 channel->index = index; 212 channel->front_info = front_info; 213 channel->state = EVTCHNL_STATE_DISCONNECTED; 214 channel->gref = GRANT_INVALID_REF; 215 page = get_zeroed_page(GFP_KERNEL); 216 if (!page) { 217 ret = -ENOMEM; 218 goto fail; 219 } 220 221 handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME, 222 type == EVTCHNL_TYPE_REQ ? 223 XENSND_FIELD_RING_REF : 224 XENSND_FIELD_EVT_RING_REF); 225 if (!handler_name) { 226 ret = -ENOMEM; 227 goto fail; 228 } 229 230 mutex_init(&channel->ring_io_lock); 231 232 if (type == EVTCHNL_TYPE_REQ) { 233 struct xen_sndif_sring *sring = (struct xen_sndif_sring *)page; 234 235 init_completion(&channel->u.req.completion); 236 mutex_init(&channel->u.req.req_io_lock); 237 SHARED_RING_INIT(sring); 238 FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE); 239 240 ret = xenbus_grant_ring(xb_dev, sring, 1, &gref); 241 if (ret < 0) { 242 channel->u.req.ring.sring = NULL; 243 goto fail; 244 } 245 246 handler = evtchnl_interrupt_req; 247 } else { 248 ret = gnttab_grant_foreign_access(xb_dev->otherend_id, 249 virt_to_gfn((void *)page), 0); 250 if (ret < 0) 251 goto fail; 252 253 channel->u.evt.page = (struct xensnd_event_page *)page; 254 gref = ret; 255 handler = evtchnl_interrupt_evt; 256 } 257 258 channel->gref = gref; 259 260 ret = xenbus_alloc_evtchn(xb_dev, &channel->port); 261 if (ret < 0) 262 goto fail; 263 264 ret = bind_evtchn_to_irq(channel->port); 265 if (ret < 0) { 266 dev_err(&xb_dev->dev, 267 "Failed to bind IRQ for domid %d port %d: %d\n", 268 front_info->xb_dev->otherend_id, channel->port, ret); 269 goto fail; 270 } 271 272 channel->irq = ret; 273 274 ret = request_threaded_irq(channel->irq, NULL, handler, 275 IRQF_ONESHOT, handler_name, channel); 276 if (ret < 0) { 277 dev_err(&xb_dev->dev, "Failed to request IRQ %d: %d\n", 278 channel->irq, ret); 279 goto fail; 280 } 281 282 kfree(handler_name); 283 return 0; 284 285 fail: 286 if (page) 287 free_page(page); 288 kfree(handler_name); 289 dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret); 290 return ret; 291 } 292 293 int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info, 294 int num_streams) 295 { 296 struct xen_front_cfg_card *cfg = &front_info->cfg; 297 struct device *dev = &front_info->xb_dev->dev; 298 int d, ret = 0; 299 300 front_info->evt_pairs = 301 kcalloc(num_streams, 302 sizeof(struct xen_snd_front_evtchnl_pair), 303 GFP_KERNEL); 304 if (!front_info->evt_pairs) 305 return -ENOMEM; 306 307 /* Iterate over devices and their streams and create event channels. */ 308 for (d = 0; d < cfg->num_pcm_instances; d++) { 309 struct xen_front_cfg_pcm_instance *pcm_instance; 310 int s, index; 311 312 pcm_instance = &cfg->pcm_instances[d]; 313 314 for (s = 0; s < pcm_instance->num_streams_pb; s++) { 315 index = pcm_instance->streams_pb[s].index; 316 317 ret = evtchnl_alloc(front_info, index, 318 &front_info->evt_pairs[index].req, 319 EVTCHNL_TYPE_REQ); 320 if (ret < 0) { 321 dev_err(dev, "Error allocating control channel\n"); 322 goto fail; 323 } 324 325 ret = evtchnl_alloc(front_info, index, 326 &front_info->evt_pairs[index].evt, 327 EVTCHNL_TYPE_EVT); 328 if (ret < 0) { 329 dev_err(dev, "Error allocating in-event channel\n"); 330 goto fail; 331 } 332 } 333 334 for (s = 0; s < pcm_instance->num_streams_cap; s++) { 335 index = pcm_instance->streams_cap[s].index; 336 337 ret = evtchnl_alloc(front_info, index, 338 &front_info->evt_pairs[index].req, 339 EVTCHNL_TYPE_REQ); 340 if (ret < 0) { 341 dev_err(dev, "Error allocating control channel\n"); 342 goto fail; 343 } 344 345 ret = evtchnl_alloc(front_info, index, 346 &front_info->evt_pairs[index].evt, 347 EVTCHNL_TYPE_EVT); 348 if (ret < 0) { 349 dev_err(dev, "Error allocating in-event channel\n"); 350 goto fail; 351 } 352 } 353 } 354 355 front_info->num_evt_pairs = num_streams; 356 return 0; 357 358 fail: 359 xen_snd_front_evtchnl_free_all(front_info); 360 return ret; 361 } 362 363 static int evtchnl_publish(struct xenbus_transaction xbt, 364 struct xen_snd_front_evtchnl *channel, 365 const char *path, const char *node_ring, 366 const char *node_chnl) 367 { 368 struct xenbus_device *xb_dev = channel->front_info->xb_dev; 369 int ret; 370 371 /* Write control channel ring reference. */ 372 ret = xenbus_printf(xbt, path, node_ring, "%u", channel->gref); 373 if (ret < 0) { 374 dev_err(&xb_dev->dev, "Error writing ring-ref: %d\n", ret); 375 return ret; 376 } 377 378 /* Write event channel ring reference. */ 379 ret = xenbus_printf(xbt, path, node_chnl, "%u", channel->port); 380 if (ret < 0) { 381 dev_err(&xb_dev->dev, "Error writing event channel: %d\n", ret); 382 return ret; 383 } 384 385 return 0; 386 } 387 388 int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info) 389 { 390 struct xen_front_cfg_card *cfg = &front_info->cfg; 391 struct xenbus_transaction xbt; 392 int ret, d; 393 394 again: 395 ret = xenbus_transaction_start(&xbt); 396 if (ret < 0) { 397 xenbus_dev_fatal(front_info->xb_dev, ret, 398 "starting transaction"); 399 return ret; 400 } 401 402 for (d = 0; d < cfg->num_pcm_instances; d++) { 403 struct xen_front_cfg_pcm_instance *pcm_instance; 404 int s, index; 405 406 pcm_instance = &cfg->pcm_instances[d]; 407 408 for (s = 0; s < pcm_instance->num_streams_pb; s++) { 409 index = pcm_instance->streams_pb[s].index; 410 411 ret = evtchnl_publish(xbt, 412 &front_info->evt_pairs[index].req, 413 pcm_instance->streams_pb[s].xenstore_path, 414 XENSND_FIELD_RING_REF, 415 XENSND_FIELD_EVT_CHNL); 416 if (ret < 0) 417 goto fail; 418 419 ret = evtchnl_publish(xbt, 420 &front_info->evt_pairs[index].evt, 421 pcm_instance->streams_pb[s].xenstore_path, 422 XENSND_FIELD_EVT_RING_REF, 423 XENSND_FIELD_EVT_EVT_CHNL); 424 if (ret < 0) 425 goto fail; 426 } 427 428 for (s = 0; s < pcm_instance->num_streams_cap; s++) { 429 index = pcm_instance->streams_cap[s].index; 430 431 ret = evtchnl_publish(xbt, 432 &front_info->evt_pairs[index].req, 433 pcm_instance->streams_cap[s].xenstore_path, 434 XENSND_FIELD_RING_REF, 435 XENSND_FIELD_EVT_CHNL); 436 if (ret < 0) 437 goto fail; 438 439 ret = evtchnl_publish(xbt, 440 &front_info->evt_pairs[index].evt, 441 pcm_instance->streams_cap[s].xenstore_path, 442 XENSND_FIELD_EVT_RING_REF, 443 XENSND_FIELD_EVT_EVT_CHNL); 444 if (ret < 0) 445 goto fail; 446 } 447 } 448 ret = xenbus_transaction_end(xbt, 0); 449 if (ret < 0) { 450 if (ret == -EAGAIN) 451 goto again; 452 453 xenbus_dev_fatal(front_info->xb_dev, ret, 454 "completing transaction"); 455 goto fail_to_end; 456 } 457 return 0; 458 fail: 459 xenbus_transaction_end(xbt, 1); 460 fail_to_end: 461 xenbus_dev_fatal(front_info->xb_dev, ret, "writing XenStore"); 462 return ret; 463 } 464 465 void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair, 466 bool is_connected) 467 { 468 enum xen_snd_front_evtchnl_state state; 469 470 if (is_connected) 471 state = EVTCHNL_STATE_CONNECTED; 472 else 473 state = EVTCHNL_STATE_DISCONNECTED; 474 475 mutex_lock(&evt_pair->req.ring_io_lock); 476 evt_pair->req.state = state; 477 mutex_unlock(&evt_pair->req.ring_io_lock); 478 479 mutex_lock(&evt_pair->evt.ring_io_lock); 480 evt_pair->evt.state = state; 481 mutex_unlock(&evt_pair->evt.ring_io_lock); 482 } 483 484 void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair) 485 { 486 mutex_lock(&evt_pair->req.ring_io_lock); 487 evt_pair->req.evt_next_id = 0; 488 mutex_unlock(&evt_pair->req.ring_io_lock); 489 490 mutex_lock(&evt_pair->evt.ring_io_lock); 491 evt_pair->evt.evt_next_id = 0; 492 mutex_unlock(&evt_pair->evt.ring_io_lock); 493 } 494 495