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