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.
  73  * Use drm_client_register() to complete the process.
  74  * The caller needs to hold a reference on @dev before calling this function.
  75  * The client is freed when the &drm_device is unregistered. See drm_client_release().
  76  *
  77  * Returns:
  78  * Zero on success or negative error code on failure.
  79  */
  80 int drm_client_init(struct drm_device *dev, struct drm_client_dev *client,
  81                     const char *name, const struct drm_client_funcs *funcs)
  82 {
  83         int ret;
  84
  85         if (!drm_core_check_feature(dev, DRIVER_MODESET) || !dev->driver->dumb_create)
  86                 return -EOPNOTSUPP;
  87
  88         if (funcs && !try_module_get(funcs->owner))
  89                 return -ENODEV;
  90
  91         client->dev = dev;
  92         client->name = name;
  93         client->funcs = funcs;
  94
  95         ret = drm_client_open(client);
  96         if (ret)
  97                 goto err_put_module;
  98
  99         drm_dev_get(dev);
 100
 101         return 0;
 102
 103 err_put_module:
 104         if (funcs)
 105                 module_put(funcs->owner);
 106
 107         return ret;
 108 }
 109 EXPORT_SYMBOL(drm_client_init);
 110
 111 /**
 112  * drm_client_register - Register client
 113  * @client: DRM client
 114  *
 115  * Add the client to the &drm_device client list to activate its callbacks.
 116  * @client must be initialized by a call to drm_client_init(). After
 117  * drm_client_register() it is no longer permissible to call drm_client_release()
 118  * directly (outside the unregister callback), instead cleanup will happen
 119  * automatically on driver unload.
 120  */
 121 void drm_client_register(struct drm_client_dev *client)
 122 {
 123         struct drm_device *dev = client->dev;
 124
 125         mutex_lock(&dev->clientlist_mutex);
 126         list_add(&client->list, &dev->clientlist);
 127         mutex_unlock(&dev->clientlist_mutex);
 128 }
 129 EXPORT_SYMBOL(drm_client_register);
 130
 131 /**
 132  * drm_client_release - Release DRM client resources
 133  * @client: DRM client
 134  *
 135  * Releases resources by closing the &drm_file that was opened by drm_client_init().
 136  * It is called automatically if the &drm_client_funcs.unregister callback is _not_ set.
 137  *
 138  * This function should only be called from the unregister callback. An exception
 139  * is fbdev which cannot free the buffer if userspace has open file descriptors.
 140  *
 141  * Note:
 142  * Clients cannot initiate a release by themselves. This is done to keep the code simple.
 143  * The driver has to be unloaded before the client can be unloaded.
 144  */
 145 void drm_client_release(struct drm_client_dev *client)
 146 {
 147         struct drm_device *dev = client->dev;
 148
 149         DRM_DEV_DEBUG_KMS(dev->dev, "%s\n", client->name);
 150
 151         drm_client_close(client);
 152         drm_dev_put(dev);
 153         if (client->funcs)
 154                 module_put(client->funcs->owner);
 155 }
 156 EXPORT_SYMBOL(drm_client_release);
 157
 158 void drm_client_dev_unregister(struct drm_device *dev)
 159 {
 160         struct drm_client_dev *client, *tmp;
 161
 162         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 163                 return;
 164
 165         mutex_lock(&dev->clientlist_mutex);
 166         list_for_each_entry_safe(client, tmp, &dev->clientlist, list) {
 167                 list_del(&client->list);
 168                 if (client->funcs && client->funcs->unregister) {
 169                         client->funcs->unregister(client);
 170                 } else {
 171                         drm_client_release(client);
 172                         kfree(client);
 173                 }
 174         }
 175         mutex_unlock(&dev->clientlist_mutex);
 176 }
 177
 178 /**
 179  * drm_client_dev_hotplug - Send hotplug event to clients
 180  * @dev: DRM device
 181  *
 182  * This function calls the &drm_client_funcs.hotplug callback on the attached clients.
 183  *
 184  * drm_kms_helper_hotplug_event() calls this function, so drivers that use it
 185  * don't need to call this function themselves.
 186  */
 187 void drm_client_dev_hotplug(struct drm_device *dev)
 188 {
 189         struct drm_client_dev *client;
 190         int ret;
 191
 192         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 193                 return;
 194
 195         mutex_lock(&dev->clientlist_mutex);
 196         list_for_each_entry(client, &dev->clientlist, list) {
 197                 if (!client->funcs || !client->funcs->hotplug)
 198                         continue;
 199
 200                 ret = client->funcs->hotplug(client);
 201                 DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", client->name, ret);
 202         }
 203         mutex_unlock(&dev->clientlist_mutex);
 204 }
 205 EXPORT_SYMBOL(drm_client_dev_hotplug);
 206
 207 void drm_client_dev_restore(struct drm_device *dev)
 208 {
 209         struct drm_client_dev *client;
 210         int ret;
 211
 212         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 213                 return;
 214
 215         mutex_lock(&dev->clientlist_mutex);
 216         list_for_each_entry(client, &dev->clientlist, list) {
 217                 if (!client->funcs || !client->funcs->restore)
 218                         continue;
 219
 220                 ret = client->funcs->restore(client);
 221                 DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", client->name, ret);
 222                 if (!ret) /* The first one to return zero gets the privilege to restore */
 223                         break;
 224         }
 225         mutex_unlock(&dev->clientlist_mutex);
 226 }
 227
 228 static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
 229 {
 230         struct drm_device *dev = buffer->client->dev;
 231
 232         drm_gem_vunmap(buffer->gem, buffer->vaddr);
 233
 234         if (buffer->gem)
 235                 drm_gem_object_put_unlocked(buffer->gem);
 236
 237         if (buffer->handle)
 238                 drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file);
 239
 240         kfree(buffer);
 241 }
 242
 243 static struct drm_client_buffer *
 244 drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 245 {
 246         struct drm_mode_create_dumb dumb_args = { };
 247         struct drm_device *dev = client->dev;
 248         struct drm_client_buffer *buffer;
 249         struct drm_gem_object *obj;
 250         void *vaddr;
 251         int ret;
 252
 253         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 254         if (!buffer)
 255                 return ERR_PTR(-ENOMEM);
 256
 257         buffer->client = client;
 258
 259         dumb_args.width = width;
 260         dumb_args.height = height;
 261         dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
 262         ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
 263         if (ret)
 264                 goto err_delete;
 265
 266         buffer->handle = dumb_args.handle;
 267         buffer->pitch = dumb_args.pitch;
 268
 269         obj = drm_gem_object_lookup(client->file, dumb_args.handle);
 270         if (!obj)  {
 271                 ret = -ENOENT;
 272                 goto err_delete;
 273         }
 274
 275         buffer->gem = obj;
 276
 277         /*
 278          * FIXME: The dependency on GEM here isn't required, we could
 279          * convert the driver handle to a dma-buf instead and use the
 280          * backend-agnostic dma-buf vmap support instead. This would
 281          * require that the handle2fd prime ioctl is reworked to pull the
 282          * fd_install step out of the driver backend hooks, to make that
 283          * final step optional for internal users.
 284          */
 285         vaddr = drm_gem_vmap(obj);
 286         if (IS_ERR(vaddr)) {
 287                 ret = PTR_ERR(vaddr);
 288                 goto err_delete;
 289         }
 290
 291         buffer->vaddr = vaddr;
 292
 293         return buffer;
 294
 295 err_delete:
 296         drm_client_buffer_delete(buffer);
 297
 298         return ERR_PTR(ret);
 299 }
 300
 301 static void drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
 302 {
 303         int ret;
 304
 305         if (!buffer->fb)
 306                 return;
 307
 308         ret = drm_mode_rmfb(buffer->client->dev, buffer->fb->base.id, buffer->client->file);
 309         if (ret)
 310                 DRM_DEV_ERROR(buffer->client->dev->dev,
 311                               "Error removing FB:%u (%d)\n", buffer->fb->base.id, ret);
 312
 313         buffer->fb = NULL;
 314 }
 315
 316 static int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
 317                                    u32 width, u32 height, u32 format)
 318 {
 319         struct drm_client_dev *client = buffer->client;
 320         struct drm_mode_fb_cmd fb_req = { };
 321         const struct drm_format_info *info;
 322         int ret;
 323
 324         info = drm_format_info(format);
 325         fb_req.bpp = info->cpp[0] * 8;
 326         fb_req.depth = info->depth;
 327         fb_req.width = width;
 328         fb_req.height = height;
 329         fb_req.handle = buffer->handle;
 330         fb_req.pitch = buffer->pitch;
 331
 332         ret = drm_mode_addfb(client->dev, &fb_req, client->file);
 333         if (ret)
 334                 return ret;
 335
 336         buffer->fb = drm_framebuffer_lookup(client->dev, buffer->client->file, fb_req.fb_id);
 337         if (WARN_ON(!buffer->fb))
 338                 return -ENOENT;
 339
 340         /* drop the reference we picked up in framebuffer lookup */
 341         drm_framebuffer_put(buffer->fb);
 342
 343         strscpy(buffer->fb->comm, client->name, TASK_COMM_LEN);
 344
 345         return 0;
 346 }
 347
 348 /**
 349  * drm_client_framebuffer_create - Create a client framebuffer
 350  * @client: DRM client
 351  * @width: Framebuffer width
 352  * @height: Framebuffer height
 353  * @format: Buffer format
 354  *
 355  * This function creates a &drm_client_buffer which consists of a
 356  * &drm_framebuffer backed by a dumb buffer.
 357  * Call drm_client_framebuffer_delete() to free the buffer.
 358  *
 359  * Returns:
 360  * Pointer to a client buffer or an error pointer on failure.
 361  */
 362 struct drm_client_buffer *
 363 drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 364 {
 365         struct drm_client_buffer *buffer;
 366         int ret;
 367
 368         buffer = drm_client_buffer_create(client, width, height, format);
 369         if (IS_ERR(buffer))
 370                 return buffer;
 371
 372         ret = drm_client_buffer_addfb(buffer, width, height, format);
 373         if (ret) {
 374                 drm_client_buffer_delete(buffer);
 375                 return ERR_PTR(ret);
 376         }
 377
 378         return buffer;
 379 }
 380 EXPORT_SYMBOL(drm_client_framebuffer_create);
 381
 382 /**
 383  * drm_client_framebuffer_delete - Delete a client framebuffer
 384  * @buffer: DRM client buffer (can be NULL)
 385  */
 386 void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
 387 {
 388         if (!buffer)
 389                 return;
 390
 391         drm_client_buffer_rmfb(buffer);
 392         drm_client_buffer_delete(buffer);
 393 }
 394 EXPORT_SYMBOL(drm_client_framebuffer_delete);
 395
 396 #ifdef CONFIG_DEBUG_FS
 397 static int drm_client_debugfs_internal_clients(struct seq_file *m, void *data)
 398 {
 399         struct drm_info_node *node = m->private;
 400         struct drm_device *dev = node->minor->dev;
 401         struct drm_printer p = drm_seq_file_printer(m);
 402         struct drm_client_dev *client;
 403
 404         mutex_lock(&dev->clientlist_mutex);
 405         list_for_each_entry(client, &dev->clientlist, list)
 406                 drm_printf(&p, "%s\n", client->name);
 407         mutex_unlock(&dev->clientlist_mutex);
 408
 409         return 0;
 410 }
 411
 412 static const struct drm_info_list drm_client_debugfs_list[] = {
 413         { "internal_clients", drm_client_debugfs_internal_clients, 0 },
 414 };
 415
 416 int drm_client_debugfs_init(struct drm_minor *minor)
 417 {
 418         return drm_debugfs_create_files(drm_client_debugfs_list,
 419                                         ARRAY_SIZE(drm_client_debugfs_list),
 420                                         minor->debugfs_root, minor);
 421 }
 422 #endif