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_new - Create a DRM client
  67  * @dev: DRM device
  68  * @client: DRM client
  69  * @name: Client name
  70  * @funcs: DRM client functions (optional)
  71  *
  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  */
  78 int drm_client_new(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) ||
  84             !dev->driver->dumb_create || !dev->driver->gem_prime_vmap)
  85                 return -ENOTSUPP;
  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         mutex_lock(&dev->clientlist_mutex);
  99         list_add(&client->list, &dev->clientlist);
 100         mutex_unlock(&dev->clientlist_mutex);
 101
 102         drm_dev_get(dev);
 103
 104         return 0;
 105
 106 err_put_module:
 107         if (funcs)
 108                 module_put(funcs->owner);
 109
 110         return ret;
 111 }
 112 EXPORT_SYMBOL(drm_client_new);
 113
 114 /**
 115  * drm_client_release - Release DRM client resources
 116  * @client: DRM client
 117  *
 118  * Releases resources by closing the &drm_file that was opened by drm_client_new().
 119  * It is called automatically if the &drm_client_funcs.unregister callback is _not_ set.
 120  *
 121  * This function should only be called from the unregister callback. An exception
 122  * is fbdev which cannot free the buffer if userspace has open file descriptors.
 123  *
 124  * Note:
 125  * Clients cannot initiate a release by themselves. This is done to keep the code simple.
 126  * The driver has to be unloaded before the client can be unloaded.
 127  */
 128 void drm_client_release(struct drm_client_dev *client)
 129 {
 130         struct drm_device *dev = client->dev;
 131
 132         DRM_DEV_DEBUG_KMS(dev->dev, "%s\n", client->name);
 133
 134         drm_client_close(client);
 135         drm_dev_put(dev);
 136         if (client->funcs)
 137                 module_put(client->funcs->owner);
 138 }
 139 EXPORT_SYMBOL(drm_client_release);
 140
 141 void drm_client_dev_unregister(struct drm_device *dev)
 142 {
 143         struct drm_client_dev *client, *tmp;
 144
 145         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 146                 return;
 147
 148         mutex_lock(&dev->clientlist_mutex);
 149         list_for_each_entry_safe(client, tmp, &dev->clientlist, list) {
 150                 list_del(&client->list);
 151                 if (client->funcs && client->funcs->unregister) {
 152                         client->funcs->unregister(client);
 153                 } else {
 154                         drm_client_release(client);
 155                         kfree(client);
 156                 }
 157         }
 158         mutex_unlock(&dev->clientlist_mutex);
 159 }
 160
 161 /**
 162  * drm_client_dev_hotplug - Send hotplug event to clients
 163  * @dev: DRM device
 164  *
 165  * This function calls the &drm_client_funcs.hotplug callback on the attached clients.
 166  *
 167  * drm_kms_helper_hotplug_event() calls this function, so drivers that use it
 168  * don't need to call this function themselves.
 169  */
 170 void drm_client_dev_hotplug(struct drm_device *dev)
 171 {
 172         struct drm_client_dev *client;
 173         int ret;
 174
 175         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 176                 return;
 177
 178         mutex_lock(&dev->clientlist_mutex);
 179         list_for_each_entry(client, &dev->clientlist, list) {
 180                 if (!client->funcs || !client->funcs->hotplug)
 181                         continue;
 182
 183                 ret = client->funcs->hotplug(client);
 184                 DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", client->name, ret);
 185         }
 186         mutex_unlock(&dev->clientlist_mutex);
 187 }
 188 EXPORT_SYMBOL(drm_client_dev_hotplug);
 189
 190 void drm_client_dev_restore(struct drm_device *dev)
 191 {
 192         struct drm_client_dev *client;
 193         int ret;
 194
 195         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 196                 return;
 197
 198         mutex_lock(&dev->clientlist_mutex);
 199         list_for_each_entry(client, &dev->clientlist, list) {
 200                 if (!client->funcs || !client->funcs->restore)
 201                         continue;
 202
 203                 ret = client->funcs->restore(client);
 204                 DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", client->name, ret);
 205                 if (!ret) /* The first one to return zero gets the privilege to restore */
 206                         break;
 207         }
 208         mutex_unlock(&dev->clientlist_mutex);
 209 }
 210
 211 static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
 212 {
 213         struct drm_device *dev = buffer->client->dev;
 214
 215         if (buffer->vaddr && dev->driver->gem_prime_vunmap)
 216                 dev->driver->gem_prime_vunmap(buffer->gem, buffer->vaddr);
 217
 218         if (buffer->gem)
 219                 drm_gem_object_put_unlocked(buffer->gem);
 220
 221         if (buffer->handle)
 222                 drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file);
 223
 224         kfree(buffer);
 225 }
 226
 227 static struct drm_client_buffer *
 228 drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 229 {
 230         struct drm_mode_create_dumb dumb_args = { };
 231         struct drm_device *dev = client->dev;
 232         struct drm_client_buffer *buffer;
 233         struct drm_gem_object *obj;
 234         void *vaddr;
 235         int ret;
 236
 237         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 238         if (!buffer)
 239                 return ERR_PTR(-ENOMEM);
 240
 241         buffer->client = client;
 242
 243         dumb_args.width = width;
 244         dumb_args.height = height;
 245         dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
 246         ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
 247         if (ret)
 248                 goto err_delete;
 249
 250         buffer->handle = dumb_args.handle;
 251         buffer->pitch = dumb_args.pitch;
 252
 253         obj = drm_gem_object_lookup(client->file, dumb_args.handle);
 254         if (!obj)  {
 255                 ret = -ENOENT;
 256                 goto err_delete;
 257         }
 258
 259         buffer->gem = obj;
 260
 261         /*
 262          * FIXME: The dependency on GEM here isn't required, we could
 263          * convert the driver handle to a dma-buf instead and use the
 264          * backend-agnostic dma-buf vmap support instead. This would
 265          * require that the handle2fd prime ioctl is reworked to pull the
 266          * fd_install step out of the driver backend hooks, to make that
 267          * final step optional for internal users.
 268          */
 269         vaddr = dev->driver->gem_prime_vmap(obj);
 270         if (!vaddr) {
 271                 ret = -ENOMEM;
 272                 goto err_delete;
 273         }
 274
 275         buffer->vaddr = vaddr;
 276
 277         return buffer;
 278
 279 err_delete:
 280         drm_client_buffer_delete(buffer);
 281
 282         return ERR_PTR(ret);
 283 }
 284
 285 static void drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
 286 {
 287         int ret;
 288
 289         if (!buffer->fb)
 290                 return;
 291
 292         ret = drm_mode_rmfb(buffer->client->dev, buffer->fb->base.id, buffer->client->file);
 293         if (ret)
 294                 DRM_DEV_ERROR(buffer->client->dev->dev,
 295                               "Error removing FB:%u (%d)\n", buffer->fb->base.id, ret);
 296
 297         buffer->fb = NULL;
 298 }
 299
 300 static int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
 301                                    u32 width, u32 height, u32 format)
 302 {
 303         struct drm_client_dev *client = buffer->client;
 304         struct drm_mode_fb_cmd fb_req = { };
 305         const struct drm_format_info *info;
 306         int ret;
 307
 308         info = drm_format_info(format);
 309         fb_req.bpp = info->cpp[0] * 8;
 310         fb_req.depth = info->depth;
 311         fb_req.width = width;
 312         fb_req.height = height;
 313         fb_req.handle = buffer->handle;
 314         fb_req.pitch = buffer->pitch;
 315
 316         ret = drm_mode_addfb(client->dev, &fb_req, client->file);
 317         if (ret)
 318                 return ret;
 319
 320         buffer->fb = drm_framebuffer_lookup(client->dev, buffer->client->file, fb_req.fb_id);
 321         if (WARN_ON(!buffer->fb))
 322                 return -ENOENT;
 323
 324         /* drop the reference we picked up in framebuffer lookup */
 325         drm_framebuffer_put(buffer->fb);
 326
 327         strscpy(buffer->fb->comm, client->name, TASK_COMM_LEN);
 328
 329         return 0;
 330 }
 331
 332 /**
 333  * drm_client_framebuffer_create - Create a client framebuffer
 334  * @client: DRM client
 335  * @width: Framebuffer width
 336  * @height: Framebuffer height
 337  * @format: Buffer format
 338  *
 339  * This function creates a &drm_client_buffer which consists of a
 340  * &drm_framebuffer backed by a dumb buffer.
 341  * Call drm_client_framebuffer_delete() to free the buffer.
 342  *
 343  * Returns:
 344  * Pointer to a client buffer or an error pointer on failure.
 345  */
 346 struct drm_client_buffer *
 347 drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
 348 {
 349         struct drm_client_buffer *buffer;
 350         int ret;
 351
 352         buffer = drm_client_buffer_create(client, width, height, format);
 353         if (IS_ERR(buffer))
 354                 return buffer;
 355
 356         ret = drm_client_buffer_addfb(buffer, width, height, format);
 357         if (ret) {
 358                 drm_client_buffer_delete(buffer);
 359                 return ERR_PTR(ret);
 360         }
 361
 362         return buffer;
 363 }
 364 EXPORT_SYMBOL(drm_client_framebuffer_create);
 365
 366 /**
 367  * drm_client_framebuffer_delete - Delete a client framebuffer
 368  * @buffer: DRM client buffer (can be NULL)
 369  */
 370 void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
 371 {
 372         if (!buffer)
 373                 return;
 374
 375         drm_client_buffer_rmfb(buffer);
 376         drm_client_buffer_delete(buffer);
 377 }
 378 EXPORT_SYMBOL(drm_client_framebuffer_delete);
 379
 380 #ifdef CONFIG_DEBUG_FS
 381 static int drm_client_debugfs_internal_clients(struct seq_file *m, void *data)
 382 {
 383         struct drm_info_node *node = m->private;
 384         struct drm_device *dev = node->minor->dev;
 385         struct drm_printer p = drm_seq_file_printer(m);
 386         struct drm_client_dev *client;
 387
 388         mutex_lock(&dev->clientlist_mutex);
 389         list_for_each_entry(client, &dev->clientlist, list)
 390                 drm_printf(&p, "%s\n", client->name);
 391         mutex_unlock(&dev->clientlist_mutex);
 392
 393         return 0;
 394 }
 395
 396 static const struct drm_info_list drm_client_debugfs_list[] = {
 397         { "internal_clients", drm_client_debugfs_internal_clients, 0 },
 398 };
 399
 400 int drm_client_debugfs_init(struct drm_minor *minor)
 401 {
 402         return drm_debugfs_create_files(drm_client_debugfs_list,
 403                                         ARRAY_SIZE(drm_client_debugfs_list),
 404                                         minor->debugfs_root, minor);
 405 }
 406 #endif