1// SPDX-License-Identifier: GPL-2.0 or MIT
  2/*
  3 * Copyright 2018 Noralf Trønnes
  4 */
  5
  6#include <linux/iosys-map.h>
  7#include <linux/list.h>
  8#include <linux/module.h>
  9#include <linux/mutex.h>
 10#include <linux/seq_file.h>
 11#include <linux/slab.h>
 12
 13#include <drm/drm_client.h>
 14#include <drm/drm_debugfs.h>
 15#include <drm/drm_device.h>
 16#include <drm/drm_drv.h>
 17#include <drm/drm_file.h>
 18#include <drm/drm_fourcc.h>
 19#include <drm/drm_framebuffer.h>
 20#include <drm/drm_gem.h>
 21#include <drm/drm_mode.h>
 22#include <drm/drm_print.h>
 23
 24#include "drm_crtc_internal.h"
 25#include "drm_internal.h"
 26
 27/**
 28 * DOC: overview
 29 *
 30 * This library provides support for clients running in the kernel like fbdev and bootsplash.
 31 *
 32 * GEM drivers which provide a GEM based dumb buffer with a virtual address are supported.
 33 */
 34
 35static int drm_client_open(struct drm_client_dev *client)
 36{
 37	struct drm_device *dev = client->dev;
 38	struct drm_file *file;
 39
 40	file = drm_file_alloc(dev->primary);
 41	if (IS_ERR(file))
 42		return PTR_ERR(file);
 43
 44	mutex_lock(&dev->filelist_mutex);
 45	list_add(&file->lhead, &dev->filelist_internal);
 46	mutex_unlock(&dev->filelist_mutex);
 47
 48	client->file = file;
 49
 50	return 0;
 51}
 52
 53static void drm_client_close(struct drm_client_dev *client)
 54{
 55	struct drm_device *dev = client->dev;
 56
 57	mutex_lock(&dev->filelist_mutex);
 58	list_del(&client->file->lhead);
 59	mutex_unlock(&dev->filelist_mutex);
 60
 61	drm_file_free(client->file);
 62}
 63
 64/**
 65 * drm_client_init - Initialise a DRM client
 66 * @dev: DRM device
 67 * @client: DRM client
 68 * @name: Client name
 69 * @funcs: DRM client functions (optional)
 70 *
 71 * This initialises the client and opens a &drm_file.
 72 * Use drm_client_register() to complete the process.
 73 * The caller needs to hold a reference on @dev before calling this function.
 74 * The client is freed when the &drm_device is unregistered. See drm_client_release().
 75 *
 76 * Returns:
 77 * Zero on success or negative error code on failure.
 78 */
 79int drm_client_init(struct drm_device *dev, struct drm_client_dev *client,
 80		    const char *name, const struct drm_client_funcs *funcs)
 81{
 82	int ret;
 83
 84	if (!drm_core_check_feature(dev, DRIVER_MODESET) || !dev->driver->dumb_create)
 85		return -EOPNOTSUPP;
 86
 87	if (funcs && !try_module_get(funcs->owner))
 88		return -ENODEV;
 89
 90	client->dev = dev;
 91	client->name = name;
 92	client->funcs = funcs;
 93
 94	ret = drm_client_modeset_create(client);
 95	if (ret)
 96		goto err_put_module;
 97
 98	ret = drm_client_open(client);
 99	if (ret)
100		goto err_free;
101
102	drm_dev_get(dev);
103
104	return 0;
105
106err_free:
107	drm_client_modeset_free(client);
108err_put_module:
109	if (funcs)
110		module_put(funcs->owner);
111
112	return ret;
113}
114EXPORT_SYMBOL(drm_client_init);
115
116/**
117 * drm_client_register - Register client
118 * @client: DRM client
119 *
120 * Add the client to the &drm_device client list to activate its callbacks.
121 * @client must be initialized by a call to drm_client_init(). After
122 * drm_client_register() it is no longer permissible to call drm_client_release()
123 * directly (outside the unregister callback), instead cleanup will happen
124 * automatically on driver unload.
125 */
126void drm_client_register(struct drm_client_dev *client)
127{
128	struct drm_device *dev = client->dev;
129
130	mutex_lock(&dev->clientlist_mutex);
131	list_add(&client->list, &dev->clientlist);
132	mutex_unlock(&dev->clientlist_mutex);
133}
134EXPORT_SYMBOL(drm_client_register);
135
136/**
137 * drm_client_release - Release DRM client resources
138 * @client: DRM client
139 *
140 * Releases resources by closing the &drm_file that was opened by drm_client_init().
141 * It is called automatically if the &drm_client_funcs.unregister callback is _not_ set.
142 *
143 * This function should only be called from the unregister callback. An exception
144 * is fbdev which cannot free the buffer if userspace has open file descriptors.
145 *
146 * Note:
147 * Clients cannot initiate a release by themselves. This is done to keep the code simple.
148 * The driver has to be unloaded before the client can be unloaded.
149 */
150void drm_client_release(struct drm_client_dev *client)
151{
152	struct drm_device *dev = client->dev;
153
154	drm_dbg_kms(dev, "%s\n", client->name);
155
156	drm_client_modeset_free(client);
157	drm_client_close(client);
158	drm_dev_put(dev);
159	if (client->funcs)
160		module_put(client->funcs->owner);
161}
162EXPORT_SYMBOL(drm_client_release);
163
164void drm_client_dev_unregister(struct drm_device *dev)
165{
166	struct drm_client_dev *client, *tmp;
167
168	if (!drm_core_check_feature(dev, DRIVER_MODESET))
169		return;
170
171	mutex_lock(&dev->clientlist_mutex);
172	list_for_each_entry_safe(client, tmp, &dev->clientlist, list) {
173		list_del(&client->list);
174		if (client->funcs && client->funcs->unregister) {
175			client->funcs->unregister(client);
176		} else {
177			drm_client_release(client);
178			kfree(client);
179		}
180	}
181	mutex_unlock(&dev->clientlist_mutex);
182}
183
184/**
185 * drm_client_dev_hotplug - Send hotplug event to clients
186 * @dev: DRM device
187 *
188 * This function calls the &drm_client_funcs.hotplug callback on the attached clients.
189 *
190 * drm_kms_helper_hotplug_event() calls this function, so drivers that use it
191 * don't need to call this function themselves.
192 */
193void drm_client_dev_hotplug(struct drm_device *dev)
194{
195	struct drm_client_dev *client;
196	int ret;
197
198	if (!drm_core_check_feature(dev, DRIVER_MODESET))
199		return;
200
201	mutex_lock(&dev->clientlist_mutex);
202	list_for_each_entry(client, &dev->clientlist, list) {
203		if (!client->funcs || !client->funcs->hotplug)
204			continue;
205
206		ret = client->funcs->hotplug(client);
207		drm_dbg_kms(dev, "%s: ret=%d\n", client->name, ret);
208	}
209	mutex_unlock(&dev->clientlist_mutex);
210}
211EXPORT_SYMBOL(drm_client_dev_hotplug);
212
213void drm_client_dev_restore(struct drm_device *dev)
214{
215	struct drm_client_dev *client;
216	int ret;
217
218	if (!drm_core_check_feature(dev, DRIVER_MODESET))
219		return;
220
221	mutex_lock(&dev->clientlist_mutex);
222	list_for_each_entry(client, &dev->clientlist, list) {
223		if (!client->funcs || !client->funcs->restore)
224			continue;
225
226		ret = client->funcs->restore(client);
227		drm_dbg_kms(dev, "%s: ret=%d\n", client->name, ret);
228		if (!ret) /* The first one to return zero gets the privilege to restore */
229			break;
230	}
231	mutex_unlock(&dev->clientlist_mutex);
232}
233
234static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
235{
236	if (buffer->gem) {
237		drm_gem_vunmap_unlocked(buffer->gem, &buffer->map);
238		drm_gem_object_put(buffer->gem);
239	}
240
241	kfree(buffer);
242}
243
244static struct drm_client_buffer *
245drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
246			 u32 format, u32 *handle)
247{
248	const struct drm_format_info *info = drm_format_info(format);
249	struct drm_mode_create_dumb dumb_args = { };
250	struct drm_device *dev = client->dev;
251	struct drm_client_buffer *buffer;
252	struct drm_gem_object *obj;
253	int ret;
254
255	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
256	if (!buffer)
257		return ERR_PTR(-ENOMEM);
258
259	buffer->client = client;
260
261	dumb_args.width = width;
262	dumb_args.height = height;
263	dumb_args.bpp = drm_format_info_bpp(info, 0);
264	ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
265	if (ret)
266		goto err_delete;
267
268	obj = drm_gem_object_lookup(client->file, dumb_args.handle);
269	if (!obj)  {
270		ret = -ENOENT;
271		goto err_delete;
272	}
273
274	buffer->pitch = dumb_args.pitch;
275	buffer->gem = obj;
276	*handle = dumb_args.handle;
277
278	return buffer;
279
280err_delete:
281	drm_client_buffer_delete(buffer);
282
283	return ERR_PTR(ret);
284}
285
286/**
287 * drm_client_buffer_vmap - Map DRM client buffer into address space
288 * @buffer: DRM client buffer
289 * @map_copy: Returns the mapped memory's address
290 *
291 * This function maps a client buffer into kernel address space. If the
292 * buffer is already mapped, it returns the existing mapping's address.
293 *
294 * Client buffer mappings are not ref'counted. Each call to
295 * drm_client_buffer_vmap() should be followed by a call to
296 * drm_client_buffer_vunmap(); or the client buffer should be mapped
297 * throughout its lifetime.
298 *
299 * The returned address is a copy of the internal value. In contrast to
300 * other vmap interfaces, you don't need it for the client's vunmap
301 * function. So you can modify it at will during blit and draw operations.
302 *
303 * Returns:
304 *	0 on success, or a negative errno code otherwise.
305 */
306int
307drm_client_buffer_vmap(struct drm_client_buffer *buffer,
308		       struct iosys_map *map_copy)
309{
310	struct iosys_map *map = &buffer->map;
311	int ret;
312
313	/*
314	 * FIXME: The dependency on GEM here isn't required, we could
315	 * convert the driver handle to a dma-buf instead and use the
316	 * backend-agnostic dma-buf vmap support instead. This would
317	 * require that the handle2fd prime ioctl is reworked to pull the
318	 * fd_install step out of the driver backend hooks, to make that
319	 * final step optional for internal users.
320	 */
321	ret = drm_gem_vmap_unlocked(buffer->gem, map);
322	if (ret)
323		return ret;
324
325	*map_copy = *map;
326
327	return 0;
328}
329EXPORT_SYMBOL(drm_client_buffer_vmap);
330
331/**
332 * drm_client_buffer_vunmap - Unmap DRM client buffer
333 * @buffer: DRM client buffer
334 *
335 * This function removes a client buffer's memory mapping. Calling this
336 * function is only required by clients that manage their buffer mappings
337 * by themselves.
338 */
339void drm_client_buffer_vunmap(struct drm_client_buffer *buffer)
340{
341	struct iosys_map *map = &buffer->map;
342
343	drm_gem_vunmap_unlocked(buffer->gem, map);
344}
345EXPORT_SYMBOL(drm_client_buffer_vunmap);
346
347static void drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
348{
349	int ret;
350
351	if (!buffer->fb)
352		return;
353
354	ret = drm_mode_rmfb(buffer->client->dev, buffer->fb->base.id, buffer->client->file);
355	if (ret)
356		drm_err(buffer->client->dev,
357			"Error removing FB:%u (%d)\n", buffer->fb->base.id, ret);
358
359	buffer->fb = NULL;
360}
361
362static int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
363				   u32 width, u32 height, u32 format,
364				   u32 handle)
365{
366	struct drm_client_dev *client = buffer->client;
367	struct drm_mode_fb_cmd fb_req = { };
368	const struct drm_format_info *info;
369	int ret;
370
371	info = drm_format_info(format);
372	fb_req.bpp = drm_format_info_bpp(info, 0);
373	fb_req.depth = info->depth;
374	fb_req.width = width;
375	fb_req.height = height;
376	fb_req.handle = handle;
377	fb_req.pitch = buffer->pitch;
378
379	ret = drm_mode_addfb(client->dev, &fb_req, client->file);
380	if (ret)
381		return ret;
382
383	buffer->fb = drm_framebuffer_lookup(client->dev, buffer->client->file, fb_req.fb_id);
384	if (WARN_ON(!buffer->fb))
385		return -ENOENT;
386
387	/* drop the reference we picked up in framebuffer lookup */
388	drm_framebuffer_put(buffer->fb);
389
390	strscpy(buffer->fb->comm, client->name, TASK_COMM_LEN);
391
392	return 0;
393}
394
395/**
396 * drm_client_framebuffer_create - Create a client framebuffer
397 * @client: DRM client
398 * @width: Framebuffer width
399 * @height: Framebuffer height
400 * @format: Buffer format
401 *
402 * This function creates a &drm_client_buffer which consists of a
403 * &drm_framebuffer backed by a dumb buffer.
404 * Call drm_client_framebuffer_delete() to free the buffer.
405 *
406 * Returns:
407 * Pointer to a client buffer or an error pointer on failure.
408 */
409struct drm_client_buffer *
410drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
411{
412	struct drm_client_buffer *buffer;
413	u32 handle;
414	int ret;
415
416	buffer = drm_client_buffer_create(client, width, height, format,
417					  &handle);
418	if (IS_ERR(buffer))
419		return buffer;
420
421	ret = drm_client_buffer_addfb(buffer, width, height, format, handle);
422
423	/*
424	 * The handle is only needed for creating the framebuffer, destroy it
425	 * again to solve a circular dependency should anybody export the GEM
426	 * object as DMA-buf. The framebuffer and our buffer structure are still
427	 * holding references to the GEM object to prevent its destruction.
428	 */
429	drm_mode_destroy_dumb(client->dev, handle, client->file);
430
431	if (ret) {
432		drm_client_buffer_delete(buffer);
433		return ERR_PTR(ret);
434	}
435
436	return buffer;
437}
438EXPORT_SYMBOL(drm_client_framebuffer_create);
439
440/**
441 * drm_client_framebuffer_delete - Delete a client framebuffer
442 * @buffer: DRM client buffer (can be NULL)
443 */
444void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
445{
446	if (!buffer)
447		return;
448
449	drm_client_buffer_rmfb(buffer);
450	drm_client_buffer_delete(buffer);
451}
452EXPORT_SYMBOL(drm_client_framebuffer_delete);
453
454/**
455 * drm_client_framebuffer_flush - Manually flush client framebuffer
456 * @buffer: DRM client buffer (can be NULL)
457 * @rect: Damage rectangle (if NULL flushes all)
458 *
459 * This calls &drm_framebuffer_funcs->dirty (if present) to flush buffer changes
460 * for drivers that need it.
461 *
462 * Returns:
463 * Zero on success or negative error code on failure.
464 */
465int drm_client_framebuffer_flush(struct drm_client_buffer *buffer, struct drm_rect *rect)
466{
467	if (!buffer || !buffer->fb || !buffer->fb->funcs->dirty)
468		return 0;
469
470	if (rect) {
471		struct drm_clip_rect clip = {
472			.x1 = rect->x1,
473			.y1 = rect->y1,
474			.x2 = rect->x2,
475			.y2 = rect->y2,
476		};
477
478		return buffer->fb->funcs->dirty(buffer->fb, buffer->client->file,
479						0, 0, &clip, 1);
480	}
481
482	return buffer->fb->funcs->dirty(buffer->fb, buffer->client->file,
483					0, 0, NULL, 0);
484}
485EXPORT_SYMBOL(drm_client_framebuffer_flush);
486
487#ifdef CONFIG_DEBUG_FS
488static int drm_client_debugfs_internal_clients(struct seq_file *m, void *data)
489{
490	struct drm_info_node *node = m->private;
491	struct drm_device *dev = node->minor->dev;
492	struct drm_printer p = drm_seq_file_printer(m);
493	struct drm_client_dev *client;
494
495	mutex_lock(&dev->clientlist_mutex);
496	list_for_each_entry(client, &dev->clientlist, list)
497		drm_printf(&p, "%s\n", client->name);
498	mutex_unlock(&dev->clientlist_mutex);
499
500	return 0;
501}
502
503static const struct drm_info_list drm_client_debugfs_list[] = {
504	{ "internal_clients", drm_client_debugfs_internal_clients, 0 },
505};
506
507void drm_client_debugfs_init(struct drm_minor *minor)
508{
509	drm_debugfs_create_files(drm_client_debugfs_list,
510				 ARRAY_SIZE(drm_client_debugfs_list),
511				 minor->debugfs_root, minor);
512}
513#endif