1 // SPDX-License-Identifier: GPL-2.0 OR MIT 2 3 /* 4 * Xen para-virtual DRM device 5 * 6 * Copyright (C) 2016-2018 EPAM Systems Inc. 7 * 8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> 9 */ 10 11 #include <linux/delay.h> 12 #include <linux/dma-mapping.h> 13 #include <linux/module.h> 14 #include <linux/of_device.h> 15 16 #include <drm/drm_atomic_helper.h> 17 #include <drm/drm_drv.h> 18 #include <drm/drm_ioctl.h> 19 #include <drm/drm_probe_helper.h> 20 #include <drm/drm_file.h> 21 #include <drm/drm_gem.h> 22 23 #include <xen/platform_pci.h> 24 #include <xen/xen.h> 25 #include <xen/xenbus.h> 26 27 #include <xen/xen-front-pgdir-shbuf.h> 28 #include <xen/interface/io/displif.h> 29 30 #include "xen_drm_front.h" 31 #include "xen_drm_front_cfg.h" 32 #include "xen_drm_front_evtchnl.h" 33 #include "xen_drm_front_gem.h" 34 #include "xen_drm_front_kms.h" 35 36 struct xen_drm_front_dbuf { 37 struct list_head list; 38 u64 dbuf_cookie; 39 u64 fb_cookie; 40 41 struct xen_front_pgdir_shbuf shbuf; 42 }; 43 44 static void dbuf_add_to_list(struct xen_drm_front_info *front_info, 45 struct xen_drm_front_dbuf *dbuf, u64 dbuf_cookie) 46 { 47 dbuf->dbuf_cookie = dbuf_cookie; 48 list_add(&dbuf->list, &front_info->dbuf_list); 49 } 50 51 static struct xen_drm_front_dbuf *dbuf_get(struct list_head *dbuf_list, 52 u64 dbuf_cookie) 53 { 54 struct xen_drm_front_dbuf *buf, *q; 55 56 list_for_each_entry_safe(buf, q, dbuf_list, list) 57 if (buf->dbuf_cookie == dbuf_cookie) 58 return buf; 59 60 return NULL; 61 } 62 63 static void dbuf_free(struct list_head *dbuf_list, u64 dbuf_cookie) 64 { 65 struct xen_drm_front_dbuf *buf, *q; 66 67 list_for_each_entry_safe(buf, q, dbuf_list, list) 68 if (buf->dbuf_cookie == dbuf_cookie) { 69 list_del(&buf->list); 70 xen_front_pgdir_shbuf_unmap(&buf->shbuf); 71 xen_front_pgdir_shbuf_free(&buf->shbuf); 72 kfree(buf); 73 break; 74 } 75 } 76 77 static void dbuf_free_all(struct list_head *dbuf_list) 78 { 79 struct xen_drm_front_dbuf *buf, *q; 80 81 list_for_each_entry_safe(buf, q, dbuf_list, list) { 82 list_del(&buf->list); 83 xen_front_pgdir_shbuf_unmap(&buf->shbuf); 84 xen_front_pgdir_shbuf_free(&buf->shbuf); 85 kfree(buf); 86 } 87 } 88 89 static struct xendispl_req * 90 be_prepare_req(struct xen_drm_front_evtchnl *evtchnl, u8 operation) 91 { 92 struct xendispl_req *req; 93 94 req = RING_GET_REQUEST(&evtchnl->u.req.ring, 95 evtchnl->u.req.ring.req_prod_pvt); 96 req->operation = operation; 97 req->id = evtchnl->evt_next_id++; 98 evtchnl->evt_id = req->id; 99 return req; 100 } 101 102 static int be_stream_do_io(struct xen_drm_front_evtchnl *evtchnl, 103 struct xendispl_req *req) 104 { 105 reinit_completion(&evtchnl->u.req.completion); 106 if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED)) 107 return -EIO; 108 109 xen_drm_front_evtchnl_flush(evtchnl); 110 return 0; 111 } 112 113 static int be_stream_wait_io(struct xen_drm_front_evtchnl *evtchnl) 114 { 115 if (wait_for_completion_timeout(&evtchnl->u.req.completion, 116 msecs_to_jiffies(XEN_DRM_FRONT_WAIT_BACK_MS)) <= 0) 117 return -ETIMEDOUT; 118 119 return evtchnl->u.req.resp_status; 120 } 121 122 int xen_drm_front_mode_set(struct xen_drm_front_drm_pipeline *pipeline, 123 u32 x, u32 y, u32 width, u32 height, 124 u32 bpp, u64 fb_cookie) 125 { 126 struct xen_drm_front_evtchnl *evtchnl; 127 struct xen_drm_front_info *front_info; 128 struct xendispl_req *req; 129 unsigned long flags; 130 int ret; 131 132 front_info = pipeline->drm_info->front_info; 133 evtchnl = &front_info->evt_pairs[pipeline->index].req; 134 if (unlikely(!evtchnl)) 135 return -EIO; 136 137 mutex_lock(&evtchnl->u.req.req_io_lock); 138 139 spin_lock_irqsave(&front_info->io_lock, flags); 140 req = be_prepare_req(evtchnl, XENDISPL_OP_SET_CONFIG); 141 req->op.set_config.x = x; 142 req->op.set_config.y = y; 143 req->op.set_config.width = width; 144 req->op.set_config.height = height; 145 req->op.set_config.bpp = bpp; 146 req->op.set_config.fb_cookie = fb_cookie; 147 148 ret = be_stream_do_io(evtchnl, req); 149 spin_unlock_irqrestore(&front_info->io_lock, flags); 150 151 if (ret == 0) 152 ret = be_stream_wait_io(evtchnl); 153 154 mutex_unlock(&evtchnl->u.req.req_io_lock); 155 return ret; 156 } 157 158 int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info, 159 u64 dbuf_cookie, u32 width, u32 height, 160 u32 bpp, u64 size, u32 offset, 161 struct page **pages) 162 { 163 struct xen_drm_front_evtchnl *evtchnl; 164 struct xen_drm_front_dbuf *dbuf; 165 struct xendispl_req *req; 166 struct xen_front_pgdir_shbuf_cfg buf_cfg; 167 unsigned long flags; 168 int ret; 169 170 evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req; 171 if (unlikely(!evtchnl)) 172 return -EIO; 173 174 dbuf = kzalloc(sizeof(*dbuf), GFP_KERNEL); 175 if (!dbuf) 176 return -ENOMEM; 177 178 dbuf_add_to_list(front_info, dbuf, dbuf_cookie); 179 180 memset(&buf_cfg, 0, sizeof(buf_cfg)); 181 buf_cfg.xb_dev = front_info->xb_dev; 182 buf_cfg.num_pages = DIV_ROUND_UP(size, PAGE_SIZE); 183 buf_cfg.pages = pages; 184 buf_cfg.pgdir = &dbuf->shbuf; 185 buf_cfg.be_alloc = front_info->cfg.be_alloc; 186 187 ret = xen_front_pgdir_shbuf_alloc(&buf_cfg); 188 if (ret < 0) 189 goto fail_shbuf_alloc; 190 191 mutex_lock(&evtchnl->u.req.req_io_lock); 192 193 spin_lock_irqsave(&front_info->io_lock, flags); 194 req = be_prepare_req(evtchnl, XENDISPL_OP_DBUF_CREATE); 195 req->op.dbuf_create.gref_directory = 196 xen_front_pgdir_shbuf_get_dir_start(&dbuf->shbuf); 197 req->op.dbuf_create.buffer_sz = size; 198 req->op.dbuf_create.data_ofs = offset; 199 req->op.dbuf_create.dbuf_cookie = dbuf_cookie; 200 req->op.dbuf_create.width = width; 201 req->op.dbuf_create.height = height; 202 req->op.dbuf_create.bpp = bpp; 203 if (buf_cfg.be_alloc) 204 req->op.dbuf_create.flags |= XENDISPL_DBUF_FLG_REQ_ALLOC; 205 206 ret = be_stream_do_io(evtchnl, req); 207 spin_unlock_irqrestore(&front_info->io_lock, flags); 208 209 if (ret < 0) 210 goto fail; 211 212 ret = be_stream_wait_io(evtchnl); 213 if (ret < 0) 214 goto fail; 215 216 ret = xen_front_pgdir_shbuf_map(&dbuf->shbuf); 217 if (ret < 0) 218 goto fail; 219 220 mutex_unlock(&evtchnl->u.req.req_io_lock); 221 return 0; 222 223 fail: 224 mutex_unlock(&evtchnl->u.req.req_io_lock); 225 fail_shbuf_alloc: 226 dbuf_free(&front_info->dbuf_list, dbuf_cookie); 227 return ret; 228 } 229 230 static int xen_drm_front_dbuf_destroy(struct xen_drm_front_info *front_info, 231 u64 dbuf_cookie) 232 { 233 struct xen_drm_front_evtchnl *evtchnl; 234 struct xendispl_req *req; 235 unsigned long flags; 236 bool be_alloc; 237 int ret; 238 239 evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req; 240 if (unlikely(!evtchnl)) 241 return -EIO; 242 243 be_alloc = front_info->cfg.be_alloc; 244 245 /* 246 * For the backend allocated buffer release references now, so backend 247 * can free the buffer. 248 */ 249 if (be_alloc) 250 dbuf_free(&front_info->dbuf_list, dbuf_cookie); 251 252 mutex_lock(&evtchnl->u.req.req_io_lock); 253 254 spin_lock_irqsave(&front_info->io_lock, flags); 255 req = be_prepare_req(evtchnl, XENDISPL_OP_DBUF_DESTROY); 256 req->op.dbuf_destroy.dbuf_cookie = dbuf_cookie; 257 258 ret = be_stream_do_io(evtchnl, req); 259 spin_unlock_irqrestore(&front_info->io_lock, flags); 260 261 if (ret == 0) 262 ret = be_stream_wait_io(evtchnl); 263 264 /* 265 * Do this regardless of communication status with the backend: 266 * if we cannot remove remote resources remove what we can locally. 267 */ 268 if (!be_alloc) 269 dbuf_free(&front_info->dbuf_list, dbuf_cookie); 270 271 mutex_unlock(&evtchnl->u.req.req_io_lock); 272 return ret; 273 } 274 275 int xen_drm_front_fb_attach(struct xen_drm_front_info *front_info, 276 u64 dbuf_cookie, u64 fb_cookie, u32 width, 277 u32 height, u32 pixel_format) 278 { 279 struct xen_drm_front_evtchnl *evtchnl; 280 struct xen_drm_front_dbuf *buf; 281 struct xendispl_req *req; 282 unsigned long flags; 283 int ret; 284 285 evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req; 286 if (unlikely(!evtchnl)) 287 return -EIO; 288 289 buf = dbuf_get(&front_info->dbuf_list, dbuf_cookie); 290 if (!buf) 291 return -EINVAL; 292 293 buf->fb_cookie = fb_cookie; 294 295 mutex_lock(&evtchnl->u.req.req_io_lock); 296 297 spin_lock_irqsave(&front_info->io_lock, flags); 298 req = be_prepare_req(evtchnl, XENDISPL_OP_FB_ATTACH); 299 req->op.fb_attach.dbuf_cookie = dbuf_cookie; 300 req->op.fb_attach.fb_cookie = fb_cookie; 301 req->op.fb_attach.width = width; 302 req->op.fb_attach.height = height; 303 req->op.fb_attach.pixel_format = pixel_format; 304 305 ret = be_stream_do_io(evtchnl, req); 306 spin_unlock_irqrestore(&front_info->io_lock, flags); 307 308 if (ret == 0) 309 ret = be_stream_wait_io(evtchnl); 310 311 mutex_unlock(&evtchnl->u.req.req_io_lock); 312 return ret; 313 } 314 315 int xen_drm_front_fb_detach(struct xen_drm_front_info *front_info, 316 u64 fb_cookie) 317 { 318 struct xen_drm_front_evtchnl *evtchnl; 319 struct xendispl_req *req; 320 unsigned long flags; 321 int ret; 322 323 evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req; 324 if (unlikely(!evtchnl)) 325 return -EIO; 326 327 mutex_lock(&evtchnl->u.req.req_io_lock); 328 329 spin_lock_irqsave(&front_info->io_lock, flags); 330 req = be_prepare_req(evtchnl, XENDISPL_OP_FB_DETACH); 331 req->op.fb_detach.fb_cookie = fb_cookie; 332 333 ret = be_stream_do_io(evtchnl, req); 334 spin_unlock_irqrestore(&front_info->io_lock, flags); 335 336 if (ret == 0) 337 ret = be_stream_wait_io(evtchnl); 338 339 mutex_unlock(&evtchnl->u.req.req_io_lock); 340 return ret; 341 } 342 343 int xen_drm_front_page_flip(struct xen_drm_front_info *front_info, 344 int conn_idx, u64 fb_cookie) 345 { 346 struct xen_drm_front_evtchnl *evtchnl; 347 struct xendispl_req *req; 348 unsigned long flags; 349 int ret; 350 351 if (unlikely(conn_idx >= front_info->num_evt_pairs)) 352 return -EINVAL; 353 354 evtchnl = &front_info->evt_pairs[conn_idx].req; 355 356 mutex_lock(&evtchnl->u.req.req_io_lock); 357 358 spin_lock_irqsave(&front_info->io_lock, flags); 359 req = be_prepare_req(evtchnl, XENDISPL_OP_PG_FLIP); 360 req->op.pg_flip.fb_cookie = fb_cookie; 361 362 ret = be_stream_do_io(evtchnl, req); 363 spin_unlock_irqrestore(&front_info->io_lock, flags); 364 365 if (ret == 0) 366 ret = be_stream_wait_io(evtchnl); 367 368 mutex_unlock(&evtchnl->u.req.req_io_lock); 369 return ret; 370 } 371 372 void xen_drm_front_on_frame_done(struct xen_drm_front_info *front_info, 373 int conn_idx, u64 fb_cookie) 374 { 375 struct xen_drm_front_drm_info *drm_info = front_info->drm_info; 376 377 if (unlikely(conn_idx >= front_info->cfg.num_connectors)) 378 return; 379 380 xen_drm_front_kms_on_frame_done(&drm_info->pipeline[conn_idx], 381 fb_cookie); 382 } 383 384 void xen_drm_front_gem_object_free(struct drm_gem_object *obj) 385 { 386 struct xen_drm_front_drm_info *drm_info = obj->dev->dev_private; 387 int idx; 388 389 if (drm_dev_enter(obj->dev, &idx)) { 390 xen_drm_front_dbuf_destroy(drm_info->front_info, 391 xen_drm_front_dbuf_to_cookie(obj)); 392 drm_dev_exit(idx); 393 } else { 394 dbuf_free(&drm_info->front_info->dbuf_list, 395 xen_drm_front_dbuf_to_cookie(obj)); 396 } 397 398 xen_drm_front_gem_free_object_unlocked(obj); 399 } 400 401 static int xen_drm_drv_dumb_create(struct drm_file *filp, 402 struct drm_device *dev, 403 struct drm_mode_create_dumb *args) 404 { 405 struct xen_drm_front_drm_info *drm_info = dev->dev_private; 406 struct drm_gem_object *obj; 407 int ret; 408 409 /* 410 * Dumb creation is a two stage process: first we create a fully 411 * constructed GEM object which is communicated to the backend, and 412 * only after that we can create GEM's handle. This is done so, 413 * because of the possible races: once you create a handle it becomes 414 * immediately visible to user-space, so the latter can try accessing 415 * object without pages etc. 416 * For details also see drm_gem_handle_create 417 */ 418 args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8); 419 args->size = args->pitch * args->height; 420 421 obj = xen_drm_front_gem_create(dev, args->size); 422 if (IS_ERR(obj)) { 423 ret = PTR_ERR(obj); 424 goto fail; 425 } 426 427 ret = xen_drm_front_dbuf_create(drm_info->front_info, 428 xen_drm_front_dbuf_to_cookie(obj), 429 args->width, args->height, args->bpp, 430 args->size, 0, 431 xen_drm_front_gem_get_pages(obj)); 432 if (ret) 433 goto fail_backend; 434 435 /* This is the tail of GEM object creation */ 436 ret = drm_gem_handle_create(filp, obj, &args->handle); 437 if (ret) 438 goto fail_handle; 439 440 /* Drop reference from allocate - handle holds it now */ 441 drm_gem_object_put(obj); 442 return 0; 443 444 fail_handle: 445 xen_drm_front_dbuf_destroy(drm_info->front_info, 446 xen_drm_front_dbuf_to_cookie(obj)); 447 fail_backend: 448 /* drop reference from allocate */ 449 drm_gem_object_put(obj); 450 fail: 451 DRM_ERROR("Failed to create dumb buffer: %d\n", ret); 452 return ret; 453 } 454 455 static void xen_drm_drv_release(struct drm_device *dev) 456 { 457 struct xen_drm_front_drm_info *drm_info = dev->dev_private; 458 struct xen_drm_front_info *front_info = drm_info->front_info; 459 460 xen_drm_front_kms_fini(drm_info); 461 462 drm_atomic_helper_shutdown(dev); 463 drm_mode_config_cleanup(dev); 464 465 if (front_info->cfg.be_alloc) 466 xenbus_switch_state(front_info->xb_dev, 467 XenbusStateInitialising); 468 469 kfree(drm_info); 470 } 471 472 static const struct file_operations xen_drm_dev_fops = { 473 .owner = THIS_MODULE, 474 .open = drm_open, 475 .release = drm_release, 476 .unlocked_ioctl = drm_ioctl, 477 #ifdef CONFIG_COMPAT 478 .compat_ioctl = drm_compat_ioctl, 479 #endif 480 .poll = drm_poll, 481 .read = drm_read, 482 .llseek = no_llseek, 483 .mmap = xen_drm_front_gem_mmap, 484 }; 485 486 static const struct drm_driver xen_drm_driver = { 487 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC, 488 .release = xen_drm_drv_release, 489 .prime_handle_to_fd = drm_gem_prime_handle_to_fd, 490 .prime_fd_to_handle = drm_gem_prime_fd_to_handle, 491 .gem_prime_import_sg_table = xen_drm_front_gem_import_sg_table, 492 .gem_prime_mmap = xen_drm_front_gem_prime_mmap, 493 .dumb_create = xen_drm_drv_dumb_create, 494 .fops = &xen_drm_dev_fops, 495 .name = "xendrm-du", 496 .desc = "Xen PV DRM Display Unit", 497 .date = "20180221", 498 .major = 1, 499 .minor = 0, 500 501 }; 502 503 static int xen_drm_drv_init(struct xen_drm_front_info *front_info) 504 { 505 struct device *dev = &front_info->xb_dev->dev; 506 struct xen_drm_front_drm_info *drm_info; 507 struct drm_device *drm_dev; 508 int ret; 509 510 DRM_INFO("Creating %s\n", xen_drm_driver.desc); 511 512 drm_info = kzalloc(sizeof(*drm_info), GFP_KERNEL); 513 if (!drm_info) { 514 ret = -ENOMEM; 515 goto fail; 516 } 517 518 drm_info->front_info = front_info; 519 front_info->drm_info = drm_info; 520 521 drm_dev = drm_dev_alloc(&xen_drm_driver, dev); 522 if (IS_ERR(drm_dev)) { 523 ret = PTR_ERR(drm_dev); 524 goto fail_dev; 525 } 526 527 drm_info->drm_dev = drm_dev; 528 529 drm_dev->dev_private = drm_info; 530 531 ret = xen_drm_front_kms_init(drm_info); 532 if (ret) { 533 DRM_ERROR("Failed to initialize DRM/KMS, ret %d\n", ret); 534 goto fail_modeset; 535 } 536 537 ret = drm_dev_register(drm_dev, 0); 538 if (ret) 539 goto fail_register; 540 541 DRM_INFO("Initialized %s %d.%d.%d %s on minor %d\n", 542 xen_drm_driver.name, xen_drm_driver.major, 543 xen_drm_driver.minor, xen_drm_driver.patchlevel, 544 xen_drm_driver.date, drm_dev->primary->index); 545 546 return 0; 547 548 fail_register: 549 drm_dev_unregister(drm_dev); 550 fail_modeset: 551 drm_kms_helper_poll_fini(drm_dev); 552 drm_mode_config_cleanup(drm_dev); 553 drm_dev_put(drm_dev); 554 fail_dev: 555 kfree(drm_info); 556 front_info->drm_info = NULL; 557 fail: 558 return ret; 559 } 560 561 static void xen_drm_drv_fini(struct xen_drm_front_info *front_info) 562 { 563 struct xen_drm_front_drm_info *drm_info = front_info->drm_info; 564 struct drm_device *dev; 565 566 if (!drm_info) 567 return; 568 569 dev = drm_info->drm_dev; 570 if (!dev) 571 return; 572 573 /* Nothing to do if device is already unplugged */ 574 if (drm_dev_is_unplugged(dev)) 575 return; 576 577 drm_kms_helper_poll_fini(dev); 578 drm_dev_unplug(dev); 579 drm_dev_put(dev); 580 581 front_info->drm_info = NULL; 582 583 xen_drm_front_evtchnl_free_all(front_info); 584 dbuf_free_all(&front_info->dbuf_list); 585 586 /* 587 * If we are not using backend allocated buffers, then tell the 588 * backend we are ready to (re)initialize. Otherwise, wait for 589 * drm_driver.release. 590 */ 591 if (!front_info->cfg.be_alloc) 592 xenbus_switch_state(front_info->xb_dev, 593 XenbusStateInitialising); 594 } 595 596 static int displback_initwait(struct xen_drm_front_info *front_info) 597 { 598 struct xen_drm_front_cfg *cfg = &front_info->cfg; 599 int ret; 600 601 cfg->front_info = front_info; 602 ret = xen_drm_front_cfg_card(front_info, cfg); 603 if (ret < 0) 604 return ret; 605 606 DRM_INFO("Have %d connector(s)\n", cfg->num_connectors); 607 /* Create event channels for all connectors and publish */ 608 ret = xen_drm_front_evtchnl_create_all(front_info); 609 if (ret < 0) 610 return ret; 611 612 return xen_drm_front_evtchnl_publish_all(front_info); 613 } 614 615 static int displback_connect(struct xen_drm_front_info *front_info) 616 { 617 xen_drm_front_evtchnl_set_state(front_info, EVTCHNL_STATE_CONNECTED); 618 return xen_drm_drv_init(front_info); 619 } 620 621 static void displback_disconnect(struct xen_drm_front_info *front_info) 622 { 623 if (!front_info->drm_info) 624 return; 625 626 /* Tell the backend to wait until we release the DRM driver. */ 627 xenbus_switch_state(front_info->xb_dev, XenbusStateReconfiguring); 628 629 xen_drm_drv_fini(front_info); 630 } 631 632 static void displback_changed(struct xenbus_device *xb_dev, 633 enum xenbus_state backend_state) 634 { 635 struct xen_drm_front_info *front_info = dev_get_drvdata(&xb_dev->dev); 636 int ret; 637 638 DRM_DEBUG("Backend state is %s, front is %s\n", 639 xenbus_strstate(backend_state), 640 xenbus_strstate(xb_dev->state)); 641 642 switch (backend_state) { 643 case XenbusStateReconfiguring: 644 case XenbusStateReconfigured: 645 case XenbusStateInitialised: 646 break; 647 648 case XenbusStateInitialising: 649 if (xb_dev->state == XenbusStateReconfiguring) 650 break; 651 652 /* recovering after backend unexpected closure */ 653 displback_disconnect(front_info); 654 break; 655 656 case XenbusStateInitWait: 657 if (xb_dev->state == XenbusStateReconfiguring) 658 break; 659 660 /* recovering after backend unexpected closure */ 661 displback_disconnect(front_info); 662 if (xb_dev->state != XenbusStateInitialising) 663 break; 664 665 ret = displback_initwait(front_info); 666 if (ret < 0) 667 xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); 668 else 669 xenbus_switch_state(xb_dev, XenbusStateInitialised); 670 break; 671 672 case XenbusStateConnected: 673 if (xb_dev->state != XenbusStateInitialised) 674 break; 675 676 ret = displback_connect(front_info); 677 if (ret < 0) { 678 displback_disconnect(front_info); 679 xenbus_dev_fatal(xb_dev, ret, "connecting backend"); 680 } else { 681 xenbus_switch_state(xb_dev, XenbusStateConnected); 682 } 683 break; 684 685 case XenbusStateClosing: 686 /* 687 * in this state backend starts freeing resources, 688 * so let it go into closed state, so we can also 689 * remove ours 690 */ 691 break; 692 693 case XenbusStateUnknown: 694 case XenbusStateClosed: 695 if (xb_dev->state == XenbusStateClosed) 696 break; 697 698 displback_disconnect(front_info); 699 break; 700 } 701 } 702 703 static int xen_drv_probe(struct xenbus_device *xb_dev, 704 const struct xenbus_device_id *id) 705 { 706 struct xen_drm_front_info *front_info; 707 struct device *dev = &xb_dev->dev; 708 int ret; 709 710 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64)); 711 if (ret < 0) { 712 DRM_ERROR("Cannot setup DMA mask, ret %d", ret); 713 return ret; 714 } 715 716 front_info = devm_kzalloc(&xb_dev->dev, 717 sizeof(*front_info), GFP_KERNEL); 718 if (!front_info) 719 return -ENOMEM; 720 721 front_info->xb_dev = xb_dev; 722 spin_lock_init(&front_info->io_lock); 723 INIT_LIST_HEAD(&front_info->dbuf_list); 724 dev_set_drvdata(&xb_dev->dev, front_info); 725 726 return xenbus_switch_state(xb_dev, XenbusStateInitialising); 727 } 728 729 static int xen_drv_remove(struct xenbus_device *dev) 730 { 731 struct xen_drm_front_info *front_info = dev_get_drvdata(&dev->dev); 732 int to = 100; 733 734 xenbus_switch_state(dev, XenbusStateClosing); 735 736 /* 737 * On driver removal it is disconnected from XenBus, 738 * so no backend state change events come via .otherend_changed 739 * callback. This prevents us from exiting gracefully, e.g. 740 * signaling the backend to free event channels, waiting for its 741 * state to change to XenbusStateClosed and cleaning at our end. 742 * Normally when front driver removed backend will finally go into 743 * XenbusStateInitWait state. 744 * 745 * Workaround: read backend's state manually and wait with time-out. 746 */ 747 while ((xenbus_read_unsigned(front_info->xb_dev->otherend, "state", 748 XenbusStateUnknown) != XenbusStateInitWait) && 749 --to) 750 msleep(10); 751 752 if (!to) { 753 unsigned int state; 754 755 state = xenbus_read_unsigned(front_info->xb_dev->otherend, 756 "state", XenbusStateUnknown); 757 DRM_ERROR("Backend state is %s while removing driver\n", 758 xenbus_strstate(state)); 759 } 760 761 xen_drm_drv_fini(front_info); 762 xenbus_frontend_closed(dev); 763 return 0; 764 } 765 766 static const struct xenbus_device_id xen_driver_ids[] = { 767 { XENDISPL_DRIVER_NAME }, 768 { "" } 769 }; 770 771 static struct xenbus_driver xen_driver = { 772 .ids = xen_driver_ids, 773 .probe = xen_drv_probe, 774 .remove = xen_drv_remove, 775 .otherend_changed = displback_changed, 776 }; 777 778 static int __init xen_drv_init(void) 779 { 780 /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */ 781 if (XEN_PAGE_SIZE != PAGE_SIZE) { 782 DRM_ERROR(XENDISPL_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n", 783 XEN_PAGE_SIZE, PAGE_SIZE); 784 return -ENODEV; 785 } 786 787 if (!xen_domain()) 788 return -ENODEV; 789 790 if (!xen_has_pv_devices()) 791 return -ENODEV; 792 793 DRM_INFO("Registering XEN PV " XENDISPL_DRIVER_NAME "\n"); 794 return xenbus_register_frontend(&xen_driver); 795 } 796 797 static void __exit xen_drv_fini(void) 798 { 799 DRM_INFO("Unregistering XEN PV " XENDISPL_DRIVER_NAME "\n"); 800 xenbus_unregister_driver(&xen_driver); 801 } 802 803 module_init(xen_drv_init); 804 module_exit(xen_drv_fini); 805 806 MODULE_DESCRIPTION("Xen para-virtualized display device frontend"); 807 MODULE_LICENSE("GPL"); 808 MODULE_ALIAS("xen:" XENDISPL_DRIVER_NAME); 809