drivers/gpu/drm/drm_client.c

   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
  34 static 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
  52 static 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 EXPORT_SYMBOL(drm_client_close);
  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  */
  79 int 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
 106 err_free:
 107         drm_client_modeset_free(client);
 108 err_put_module:
 109         if (funcs)
 110                 module_put(funcs->owner);
 111
 112         return ret;
 113 }
 114 EXPORT_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  */
 126 void 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 }
 134 EXPORT_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  */
 150 void drm_client_release(struct drm_client_dev *client)
 151 {
 152         struct drm_device *dev = client->dev;
 153
 154         DRM_DEV_DEBUG_KMS(dev->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 }
 162 EXPORT_SYMBOL(drm_client_release);
 163
 164 void 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  */
 193 void 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_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", client->name, ret);
 208         }
 209         mutex_unlock(&dev->clientlist_mutex);
 210 }
 211 EXPORT_SYMBOL(drm_client_dev_hotplug);
 212
 213 void 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_DEV_DEBUG_KMS(dev->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
 234 static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
 235 {
 236         struct drm_device *dev = buffer->client->dev;
 237
 238         drm_gem_vunmap(buffer->gem, buffer->vaddr);
 239
 240         if (buffer->gem)
 241                 drm_gem_object_put_unlocked(buffer->gem);
 242
 243         if (buffer->handle)
 244                 drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file);
 245
 246         kfree(buffer);
 247 }
 248
 249 static struct drm_client_buffer *
 250 drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 251 {
 252         const struct drm_format_info *info = drm_format_info(format);
 253         struct drm_mode_create_dumb dumb_args = { };
 254         struct drm_device *dev = client->dev;
 255         struct drm_client_buffer *buffer;
 256         struct drm_gem_object *obj;
 257         void *vaddr;
 258         int ret;
 259
 260         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 261         if (!buffer)
 262                 return ERR_PTR(-ENOMEM);
 263
 264         buffer->client = client;
 265
 266         dumb_args.width = width;
 267         dumb_args.height = height;
 268         dumb_args.bpp = info->cpp[0] * 8;
 269         ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
 270         if (ret)
 271                 goto err_delete;
 272
 273         buffer->handle = dumb_args.handle;
 274         buffer->pitch = dumb_args.pitch;
 275
 276         obj = drm_gem_object_lookup(client->file, dumb_args.handle);
 277         if (!obj)  {
 278                 ret = -ENOENT;
 279                 goto err_delete;
 280         }
 281
 282         buffer->gem = obj;
 283
 284         /*
 285          * FIXME: The dependency on GEM here isn't required, we could
 286          * convert the driver handle to a dma-buf instead and use the
 287          * backend-agnostic dma-buf vmap support instead. This would
 288          * require that the handle2fd prime ioctl is reworked to pull the
 289          * fd_install step out of the driver backend hooks, to make that
 290          * final step optional for internal users.
 291          */
 292         vaddr = drm_gem_vmap(obj);
 293         if (IS_ERR(vaddr)) {
 294                 ret = PTR_ERR(vaddr);
 295                 goto err_delete;
 296         }
 297
 298         buffer->vaddr = vaddr;
 299
 300         return buffer;
 301
 302 err_delete:
 303         drm_client_buffer_delete(buffer);
 304
 305         return ERR_PTR(ret);
 306 }
 307
 308 static void drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
 309 {
 310         int ret;
 311
 312         if (!buffer->fb)
 313                 return;
 314
 315         ret = drm_mode_rmfb(buffer->client->dev, buffer->fb->base.id, buffer->client->file);
 316         if (ret)
 317                 DRM_DEV_ERROR(buffer->client->dev->dev,
 318                               "Error removing FB:%u (%d)\n", buffer->fb->base.id, ret);
 319
 320         buffer->fb = NULL;
 321 }
 322
 323 static int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
 324                                    u32 width, u32 height, u32 format)
 325 {
 326         struct drm_client_dev *client = buffer->client;
 327         struct drm_mode_fb_cmd fb_req = { };
 328         const struct drm_format_info *info;
 329         int ret;
 330
 331         info = drm_format_info(format);
 332         fb_req.bpp = info->cpp[0] * 8;
 333         fb_req.depth = info->depth;
 334         fb_req.width = width;
 335         fb_req.height = height;
 336         fb_req.handle = buffer->handle;
 337         fb_req.pitch = buffer->pitch;
 338
 339         ret = drm_mode_addfb(client->dev, &fb_req, client->file);
 340         if (ret)
 341                 return ret;
 342
 343         buffer->fb = drm_framebuffer_lookup(client->dev, buffer->client->file, fb_req.fb_id);
 344         if (WARN_ON(!buffer->fb))
 345                 return -ENOENT;
 346
 347         /* drop the reference we picked up in framebuffer lookup */
 348         drm_framebuffer_put(buffer->fb);
 349
 350         strscpy(buffer->fb->comm, client->name, TASK_COMM_LEN);
 351
 352         return 0;
 353 }
 354
 355 /**
 356  * drm_client_framebuffer_create - Create a client framebuffer
 357  * @client: DRM client
 358  * @width: Framebuffer width
 359  * @height: Framebuffer height
 360  * @format: Buffer format
 361  *
 362  * This function creates a &drm_client_buffer which consists of a
 363  * &drm_framebuffer backed by a dumb buffer.
 364  * Call drm_client_framebuffer_delete() to free the buffer.
 365  *
 366  * Returns:
 367  * Pointer to a client buffer or an error pointer on failure.
 368  */
 369 struct drm_client_buffer *
 370 drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 371 {
 372         struct drm_client_buffer *buffer;
 373         int ret;
 374
 375         buffer = drm_client_buffer_create(client, width, height, format);
 376         if (IS_ERR(buffer))
 377                 return buffer;
 378
 379         ret = drm_client_buffer_addfb(buffer, width, height, format);
 380         if (ret) {
 381                 drm_client_buffer_delete(buffer);
 382                 return ERR_PTR(ret);
 383         }
 384
 385         return buffer;
 386 }
 387 EXPORT_SYMBOL(drm_client_framebuffer_create);
 388
 389 /**
 390  * drm_client_framebuffer_delete - Delete a client framebuffer
 391  * @buffer: DRM client buffer (can be NULL)
 392  */
 393 void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
 394 {
 395         if (!buffer)
 396                 return;
 397
 398         drm_client_buffer_rmfb(buffer);
 399         drm_client_buffer_delete(buffer);
 400 }
 401 EXPORT_SYMBOL(drm_client_framebuffer_delete);
 402
 403 #ifdef CONFIG_DEBUG_FS
 404 static int drm_client_debugfs_internal_clients(struct seq_file *m, void *data)
 405 {
 406         struct drm_info_node *node = m->private;
 407         struct drm_device *dev = node->minor->dev;
 408         struct drm_printer p = drm_seq_file_printer(m);
 409         struct drm_client_dev *client;
 410
 411         mutex_lock(&dev->clientlist_mutex);
 412         list_for_each_entry(client, &dev->clientlist, list)
 413                 drm_printf(&p, "%s\n", client->name);
 414         mutex_unlock(&dev->clientlist_mutex);
 415
 416         return 0;
 417 }
 418
 419 static const struct drm_info_list drm_client_debugfs_list[] = {
 420         { "internal_clients", drm_client_debugfs_internal_clients, 0 },
 421 };
 422
 423 int drm_client_debugfs_init(struct drm_minor *minor)
 424 {
 425         return drm_debugfs_create_files(drm_client_debugfs_list,
 426                                         ARRAY_SIZE(drm_client_debugfs_list),
 427                                         minor->debugfs_root, minor);
 428 }
 429 #endif