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