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_gem.h>
  19 #include <drm/drm_mode.h>
  20 #include <drm/drm_print.h>
  21 #include <drm/drmP.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  * Currently it's only partially implemented, just enough to support fbdev.
  31  *
  32  * GEM drivers which provide a GEM based dumb buffer with a virtual address are supported.
  33  */
  34
  35 static 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
  53 static 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 EXPORT_SYMBOL(drm_client_close);
  64
  65 /**
  66  * drm_client_init - Initialise a DRM client
  67  * @dev: DRM device
  68  * @client: DRM client
  69  * @name: Client name
  70  * @funcs: DRM client functions (optional)
  71  *
  72  * This initialises the client and opens a &drm_file. Use drm_client_add() 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_open(client);
  95         if (ret)
  96                 goto err_put_module;
  97
  98         drm_dev_get(dev);
  99
 100         return 0;
 101
 102 err_put_module:
 103         if (funcs)
 104                 module_put(funcs->owner);
 105
 106         return ret;
 107 }
 108 EXPORT_SYMBOL(drm_client_init);
 109
 110 /**
 111  * drm_client_add - Add client to the device list
 112  * @client: DRM client
 113  *
 114  * Add the client to the &drm_device client list to activate its callbacks.
 115  * @client must be initialized by a call to drm_client_init(). After
 116  * drm_client_add() it is no longer permissible to call drm_client_release()
 117  * directly (outside the unregister callback), instead cleanup will happen
 118  * automatically on driver unload.
 119  */
 120 void drm_client_add(struct drm_client_dev *client)
 121 {
 122         struct drm_device *dev = client->dev;
 123
 124         mutex_lock(&dev->clientlist_mutex);
 125         list_add(&client->list, &dev->clientlist);
 126         mutex_unlock(&dev->clientlist_mutex);
 127 }
 128 EXPORT_SYMBOL(drm_client_add);
 129
 130 /**
 131  * drm_client_release - Release DRM client resources
 132  * @client: DRM client
 133  *
 134  * Releases resources by closing the &drm_file that was opened by drm_client_init().
 135  * It is called automatically if the &drm_client_funcs.unregister callback is _not_ set.
 136  *
 137  * This function should only be called from the unregister callback. An exception
 138  * is fbdev which cannot free the buffer if userspace has open file descriptors.
 139  *
 140  * Note:
 141  * Clients cannot initiate a release by themselves. This is done to keep the code simple.
 142  * The driver has to be unloaded before the client can be unloaded.
 143  */
 144 void drm_client_release(struct drm_client_dev *client)
 145 {
 146         struct drm_device *dev = client->dev;
 147
 148         DRM_DEV_DEBUG_KMS(dev->dev, "%s\n", client->name);
 149
 150         drm_client_close(client);
 151         drm_dev_put(dev);
 152         if (client->funcs)
 153                 module_put(client->funcs->owner);
 154 }
 155 EXPORT_SYMBOL(drm_client_release);
 156
 157 void drm_client_dev_unregister(struct drm_device *dev)
 158 {
 159         struct drm_client_dev *client, *tmp;
 160
 161         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 162                 return;
 163
 164         mutex_lock(&dev->clientlist_mutex);
 165         list_for_each_entry_safe(client, tmp, &dev->clientlist, list) {
 166                 list_del(&client->list);
 167                 if (client->funcs && client->funcs->unregister) {
 168                         client->funcs->unregister(client);
 169                 } else {
 170                         drm_client_release(client);
 171                         kfree(client);
 172                 }
 173         }
 174         mutex_unlock(&dev->clientlist_mutex);
 175 }
 176
 177 /**
 178  * drm_client_dev_hotplug - Send hotplug event to clients
 179  * @dev: DRM device
 180  *
 181  * This function calls the &drm_client_funcs.hotplug callback on the attached clients.
 182  *
 183  * drm_kms_helper_hotplug_event() calls this function, so drivers that use it
 184  * don't need to call this function themselves.
 185  */
 186 void drm_client_dev_hotplug(struct drm_device *dev)
 187 {
 188         struct drm_client_dev *client;
 189         int ret;
 190
 191         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 192                 return;
 193
 194         mutex_lock(&dev->clientlist_mutex);
 195         list_for_each_entry(client, &dev->clientlist, list) {
 196                 if (!client->funcs || !client->funcs->hotplug)
 197                         continue;
 198
 199                 ret = client->funcs->hotplug(client);
 200                 DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", client->name, ret);
 201         }
 202         mutex_unlock(&dev->clientlist_mutex);
 203 }
 204 EXPORT_SYMBOL(drm_client_dev_hotplug);
 205
 206 void drm_client_dev_restore(struct drm_device *dev)
 207 {
 208         struct drm_client_dev *client;
 209         int ret;
 210
 211         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 212                 return;
 213
 214         mutex_lock(&dev->clientlist_mutex);
 215         list_for_each_entry(client, &dev->clientlist, list) {
 216                 if (!client->funcs || !client->funcs->restore)
 217                         continue;
 218
 219                 ret = client->funcs->restore(client);
 220                 DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", client->name, ret);
 221                 if (!ret) /* The first one to return zero gets the privilege to restore */
 222                         break;
 223         }
 224         mutex_unlock(&dev->clientlist_mutex);
 225 }
 226
 227 static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
 228 {
 229         struct drm_device *dev = buffer->client->dev;
 230
 231         drm_gem_vunmap(buffer->gem, buffer->vaddr);
 232
 233         if (buffer->gem)
 234                 drm_gem_object_put_unlocked(buffer->gem);
 235
 236         if (buffer->handle)
 237                 drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file);
 238
 239         kfree(buffer);
 240 }
 241
 242 static struct drm_client_buffer *
 243 drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 244 {
 245         struct drm_mode_create_dumb dumb_args = { };
 246         struct drm_device *dev = client->dev;
 247         struct drm_client_buffer *buffer;
 248         struct drm_gem_object *obj;
 249         void *vaddr;
 250         int ret;
 251
 252         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 253         if (!buffer)
 254                 return ERR_PTR(-ENOMEM);
 255
 256         buffer->client = client;
 257
 258         dumb_args.width = width;
 259         dumb_args.height = height;
 260         dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
 261         ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
 262         if (ret)
 263                 goto err_delete;
 264
 265         buffer->handle = dumb_args.handle;
 266         buffer->pitch = dumb_args.pitch;
 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->gem = obj;
 275
 276         /*
 277          * FIXME: The dependency on GEM here isn't required, we could
 278          * convert the driver handle to a dma-buf instead and use the
 279          * backend-agnostic dma-buf vmap support instead. This would
 280          * require that the handle2fd prime ioctl is reworked to pull the
 281          * fd_install step out of the driver backend hooks, to make that
 282          * final step optional for internal users.
 283          */
 284         vaddr = drm_gem_vmap(obj);
 285         if (IS_ERR(vaddr)) {
 286                 ret = PTR_ERR(vaddr);
 287                 goto err_delete;
 288         }
 289
 290         buffer->vaddr = vaddr;
 291
 292         return buffer;
 293
 294 err_delete:
 295         drm_client_buffer_delete(buffer);
 296
 297         return ERR_PTR(ret);
 298 }
 299
 300 static void drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
 301 {
 302         int ret;
 303
 304         if (!buffer->fb)
 305                 return;
 306
 307         ret = drm_mode_rmfb(buffer->client->dev, buffer->fb->base.id, buffer->client->file);
 308         if (ret)
 309                 DRM_DEV_ERROR(buffer->client->dev->dev,
 310                               "Error removing FB:%u (%d)\n", buffer->fb->base.id, ret);
 311
 312         buffer->fb = NULL;
 313 }
 314
 315 static int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
 316                                    u32 width, u32 height, u32 format)
 317 {
 318         struct drm_client_dev *client = buffer->client;
 319         struct drm_mode_fb_cmd fb_req = { };
 320         const struct drm_format_info *info;
 321         int ret;
 322
 323         info = drm_format_info(format);
 324         fb_req.bpp = info->cpp[0] * 8;
 325         fb_req.depth = info->depth;
 326         fb_req.width = width;
 327         fb_req.height = height;
 328         fb_req.handle = buffer->handle;
 329         fb_req.pitch = buffer->pitch;
 330
 331         ret = drm_mode_addfb(client->dev, &fb_req, client->file);
 332         if (ret)
 333                 return ret;
 334
 335         buffer->fb = drm_framebuffer_lookup(client->dev, buffer->client->file, fb_req.fb_id);
 336         if (WARN_ON(!buffer->fb))
 337                 return -ENOENT;
 338
 339         /* drop the reference we picked up in framebuffer lookup */
 340         drm_framebuffer_put(buffer->fb);
 341
 342         strscpy(buffer->fb->comm, client->name, TASK_COMM_LEN);
 343
 344         return 0;
 345 }
 346
 347 /**
 348  * drm_client_framebuffer_create - Create a client framebuffer
 349  * @client: DRM client
 350  * @width: Framebuffer width
 351  * @height: Framebuffer height
 352  * @format: Buffer format
 353  *
 354  * This function creates a &drm_client_buffer which consists of a
 355  * &drm_framebuffer backed by a dumb buffer.
 356  * Call drm_client_framebuffer_delete() to free the buffer.
 357  *
 358  * Returns:
 359  * Pointer to a client buffer or an error pointer on failure.
 360  */
 361 struct drm_client_buffer *
 362 drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 363 {
 364         struct drm_client_buffer *buffer;
 365         int ret;
 366
 367         buffer = drm_client_buffer_create(client, width, height, format);
 368         if (IS_ERR(buffer))
 369                 return buffer;
 370
 371         ret = drm_client_buffer_addfb(buffer, width, height, format);
 372         if (ret) {
 373                 drm_client_buffer_delete(buffer);
 374                 return ERR_PTR(ret);
 375         }
 376
 377         return buffer;
 378 }
 379 EXPORT_SYMBOL(drm_client_framebuffer_create);
 380
 381 /**
 382  * drm_client_framebuffer_delete - Delete a client framebuffer
 383  * @buffer: DRM client buffer (can be NULL)
 384  */
 385 void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
 386 {
 387         if (!buffer)
 388                 return;
 389
 390         drm_client_buffer_rmfb(buffer);
 391         drm_client_buffer_delete(buffer);
 392 }
 393 EXPORT_SYMBOL(drm_client_framebuffer_delete);
 394
 395 #ifdef CONFIG_DEBUG_FS
 396 static int drm_client_debugfs_internal_clients(struct seq_file *m, void *data)
 397 {
 398         struct drm_info_node *node = m->private;
 399         struct drm_device *dev = node->minor->dev;
 400         struct drm_printer p = drm_seq_file_printer(m);
 401         struct drm_client_dev *client;
 402
 403         mutex_lock(&dev->clientlist_mutex);
 404         list_for_each_entry(client, &dev->clientlist, list)
 405                 drm_printf(&p, "%s\n", client->name);
 406         mutex_unlock(&dev->clientlist_mutex);
 407
 408         return 0;
 409 }
 410
 411 static const struct drm_info_list drm_client_debugfs_list[] = {
 412         { "internal_clients", drm_client_debugfs_internal_clients, 0 },
 413 };
 414
 415 int drm_client_debugfs_init(struct drm_minor *minor)
 416 {
 417         return drm_debugfs_create_files(drm_client_debugfs_list,
 418                                         ARRAY_SIZE(drm_client_debugfs_list),
 419                                         minor->debugfs_root, minor);
 420 }
 421 #endif