drivers/gpu/drm/drm_fbdev_generic.c

   1 // SPDX-License-Identifier: MIT
   2
   3 #include <linux/moduleparam.h>
   4 #include <linux/vmalloc.h>
   5
   6 #include <drm/drm_crtc_helper.h>
   7 #include <drm/drm_drv.h>
   8 #include <drm/drm_fb_helper.h>
   9 #include <drm/drm_framebuffer.h>
  10 #include <drm/drm_print.h>
  11
  12 #include <drm/drm_fbdev_generic.h>
  13
  14 static bool drm_fbdev_use_shadow_fb(struct drm_fb_helper *fb_helper)
  15 {
  16         struct drm_device *dev = fb_helper->dev;
  17         struct drm_framebuffer *fb = fb_helper->fb;
  18
  19         return dev->mode_config.prefer_shadow_fbdev ||
  20                dev->mode_config.prefer_shadow ||
  21                fb->funcs->dirty;
  22 }
  23
  24 /* @user: 1=userspace, 0=fbcon */
  25 static int drm_fbdev_fb_open(struct fb_info *info, int user)
  26 {
  27         struct drm_fb_helper *fb_helper = info->par;
  28
  29         /* No need to take a ref for fbcon because it unbinds on unregister */
  30         if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
  31                 return -ENODEV;
  32
  33         return 0;
  34 }
  35
  36 static int drm_fbdev_fb_release(struct fb_info *info, int user)
  37 {
  38         struct drm_fb_helper *fb_helper = info->par;
  39
  40         if (user)
  41                 module_put(fb_helper->dev->driver->fops->owner);
  42
  43         return 0;
  44 }
  45
  46 static void drm_fbdev_cleanup(struct drm_fb_helper *fb_helper)
  47 {
  48         struct fb_info *fbi = fb_helper->info;
  49         void *shadow = NULL;
  50
  51         if (!fb_helper->dev)
  52                 return;
  53
  54         if (fbi) {
  55                 if (fbi->fbdefio)
  56                         fb_deferred_io_cleanup(fbi);
  57                 if (drm_fbdev_use_shadow_fb(fb_helper))
  58                         shadow = fbi->screen_buffer;
  59         }
  60
  61         drm_fb_helper_fini(fb_helper);
  62
  63         if (shadow)
  64                 vfree(shadow);
  65         else if (fb_helper->buffer)
  66                 drm_client_buffer_vunmap(fb_helper->buffer);
  67
  68         drm_client_framebuffer_delete(fb_helper->buffer);
  69 }
  70
  71 static void drm_fbdev_release(struct drm_fb_helper *fb_helper)
  72 {
  73         drm_fbdev_cleanup(fb_helper);
  74         drm_client_release(&fb_helper->client);
  75         kfree(fb_helper);
  76 }
  77
  78 /*
  79  * fb_ops.fb_destroy is called by the last put_fb_info() call at the end of
  80  * unregister_framebuffer() or fb_release().
  81  */
  82 static void drm_fbdev_fb_destroy(struct fb_info *info)
  83 {
  84         drm_fbdev_release(info->par);
  85 }
  86
  87 static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  88 {
  89         struct drm_fb_helper *fb_helper = info->par;
  90
  91         if (drm_fbdev_use_shadow_fb(fb_helper))
  92                 return fb_deferred_io_mmap(info, vma);
  93         else if (fb_helper->dev->driver->gem_prime_mmap)
  94                 return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma);
  95         else
  96                 return -ENODEV;
  97 }
  98
  99 static bool drm_fbdev_use_iomem(struct fb_info *info)
 100 {
 101         struct drm_fb_helper *fb_helper = info->par;
 102         struct drm_client_buffer *buffer = fb_helper->buffer;
 103
 104         return !drm_fbdev_use_shadow_fb(fb_helper) && buffer->map.is_iomem;
 105 }
 106
 107 static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf,
 108                                  size_t count, loff_t *ppos)
 109 {
 110         ssize_t ret;
 111
 112         if (drm_fbdev_use_iomem(info))
 113                 ret = drm_fb_helper_cfb_read(info, buf, count, ppos);
 114         else
 115                 ret = drm_fb_helper_sys_read(info, buf, count, ppos);
 116
 117         return ret;
 118 }
 119
 120 static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf,
 121                                   size_t count, loff_t *ppos)
 122 {
 123         ssize_t ret;
 124
 125         if (drm_fbdev_use_iomem(info))
 126                 ret = drm_fb_helper_cfb_write(info, buf, count, ppos);
 127         else
 128                 ret = drm_fb_helper_sys_write(info, buf, count, ppos);
 129
 130         return ret;
 131 }
 132
 133 static void drm_fbdev_fb_fillrect(struct fb_info *info,
 134                                   const struct fb_fillrect *rect)
 135 {
 136         if (drm_fbdev_use_iomem(info))
 137                 drm_fb_helper_cfb_fillrect(info, rect);
 138         else
 139                 drm_fb_helper_sys_fillrect(info, rect);
 140 }
 141
 142 static void drm_fbdev_fb_copyarea(struct fb_info *info,
 143                                   const struct fb_copyarea *area)
 144 {
 145         if (drm_fbdev_use_iomem(info))
 146                 drm_fb_helper_cfb_copyarea(info, area);
 147         else
 148                 drm_fb_helper_sys_copyarea(info, area);
 149 }
 150
 151 static void drm_fbdev_fb_imageblit(struct fb_info *info,
 152                                    const struct fb_image *image)
 153 {
 154         if (drm_fbdev_use_iomem(info))
 155                 drm_fb_helper_cfb_imageblit(info, image);
 156         else
 157                 drm_fb_helper_sys_imageblit(info, image);
 158 }
 159
 160 static const struct fb_ops drm_fbdev_fb_ops = {
 161         .owner          = THIS_MODULE,
 162         DRM_FB_HELPER_DEFAULT_OPS,
 163         .fb_open        = drm_fbdev_fb_open,
 164         .fb_release     = drm_fbdev_fb_release,
 165         .fb_destroy     = drm_fbdev_fb_destroy,
 166         .fb_mmap        = drm_fbdev_fb_mmap,
 167         .fb_read        = drm_fbdev_fb_read,
 168         .fb_write       = drm_fbdev_fb_write,
 169         .fb_fillrect    = drm_fbdev_fb_fillrect,
 170         .fb_copyarea    = drm_fbdev_fb_copyarea,
 171         .fb_imageblit   = drm_fbdev_fb_imageblit,
 172 };
 173
 174 /*
 175  * This function uses the client API to create a framebuffer backed by a dumb buffer.
 176  */
 177 static int drm_fbdev_fb_probe(struct drm_fb_helper *fb_helper,
 178                               struct drm_fb_helper_surface_size *sizes)
 179 {
 180         struct drm_client_dev *client = &fb_helper->client;
 181         struct drm_device *dev = fb_helper->dev;
 182         struct drm_client_buffer *buffer;
 183         struct drm_framebuffer *fb;
 184         struct fb_info *fbi;
 185         u32 format;
 186         struct iosys_map map;
 187         int ret;
 188
 189         drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
 190                     sizes->surface_width, sizes->surface_height,
 191                     sizes->surface_bpp);
 192
 193         format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
 194         buffer = drm_client_framebuffer_create(client, sizes->surface_width,
 195                                                sizes->surface_height, format);
 196         if (IS_ERR(buffer))
 197                 return PTR_ERR(buffer);
 198
 199         fb_helper->buffer = buffer;
 200         fb_helper->fb = buffer->fb;
 201         fb = buffer->fb;
 202
 203         fbi = drm_fb_helper_alloc_info(fb_helper);
 204         if (IS_ERR(fbi))
 205                 return PTR_ERR(fbi);
 206
 207         fbi->fbops = &drm_fbdev_fb_ops;
 208         fbi->screen_size = sizes->surface_height * fb->pitches[0];
 209         fbi->fix.smem_len = fbi->screen_size;
 210         fbi->flags = FBINFO_DEFAULT;
 211
 212         drm_fb_helper_fill_info(fbi, fb_helper, sizes);
 213
 214         if (drm_fbdev_use_shadow_fb(fb_helper)) {
 215                 fbi->screen_buffer = vzalloc(fbi->screen_size);
 216                 if (!fbi->screen_buffer)
 217                         return -ENOMEM;
 218                 fbi->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
 219
 220                 /* Set a default deferred I/O handler */
 221                 fb_helper->fbdefio.delay = HZ / 20;
 222                 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
 223
 224                 fbi->fbdefio = &fb_helper->fbdefio;
 225                 ret = fb_deferred_io_init(fbi);
 226                 if (ret)
 227                         return ret;
 228         } else {
 229                 /* buffer is mapped for HW framebuffer */
 230                 ret = drm_client_buffer_vmap(fb_helper->buffer, &map);
 231                 if (ret)
 232                         return ret;
 233                 if (map.is_iomem) {
 234                         fbi->screen_base = map.vaddr_iomem;
 235                 } else {
 236                         fbi->screen_buffer = map.vaddr;
 237                         fbi->flags |= FBINFO_VIRTFB;
 238                 }
 239
 240                 /*
 241                  * Shamelessly leak the physical address to user-space. As
 242                  * page_to_phys() is undefined for I/O memory, warn in this
 243                  * case.
 244                  */
 245 #if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
 246                 if (fb_helper->hint_leak_smem_start && fbi->fix.smem_start == 0 &&
 247                     !drm_WARN_ON_ONCE(dev, map.is_iomem))
 248                         fbi->fix.smem_start =
 249                                 page_to_phys(virt_to_page(fbi->screen_buffer));
 250 #endif
 251         }
 252
 253         return 0;
 254 }
 255
 256 static void drm_fbdev_damage_blit_real(struct drm_fb_helper *fb_helper,
 257                                        struct drm_clip_rect *clip,
 258                                        struct iosys_map *dst)
 259 {
 260         struct drm_framebuffer *fb = fb_helper->fb;
 261         size_t offset = clip->y1 * fb->pitches[0];
 262         size_t len = clip->x2 - clip->x1;
 263         unsigned int y;
 264         void *src;
 265
 266         switch (drm_format_info_bpp(fb->format, 0)) {
 267         case 1:
 268                 offset += clip->x1 / 8;
 269                 len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
 270                 break;
 271         case 2:
 272                 offset += clip->x1 / 4;
 273                 len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
 274                 break;
 275         case 4:
 276                 offset += clip->x1 / 2;
 277                 len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
 278                 break;
 279         default:
 280                 offset += clip->x1 * fb->format->cpp[0];
 281                 len *= fb->format->cpp[0];
 282                 break;
 283         }
 284
 285         src = fb_helper->info->screen_buffer + offset;
 286         iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
 287
 288         for (y = clip->y1; y < clip->y2; y++) {
 289                 iosys_map_memcpy_to(dst, 0, src, len);
 290                 iosys_map_incr(dst, fb->pitches[0]);
 291                 src += fb->pitches[0];
 292         }
 293 }
 294
 295 static int drm_fbdev_damage_blit(struct drm_fb_helper *fb_helper,
 296                                  struct drm_clip_rect *clip)
 297 {
 298         struct drm_client_buffer *buffer = fb_helper->buffer;
 299         struct iosys_map map, dst;
 300         int ret;
 301
 302         /*
 303          * We have to pin the client buffer to its current location while
 304          * flushing the shadow buffer. In the general case, concurrent
 305          * modesetting operations could try to move the buffer and would
 306          * fail. The modeset has to be serialized by acquiring the reservation
 307          * object of the underlying BO here.
 308          *
 309          * For fbdev emulation, we only have to protect against fbdev modeset
 310          * operations. Nothing else will involve the client buffer's BO. So it
 311          * is sufficient to acquire struct drm_fb_helper.lock here.
 312          */
 313         mutex_lock(&fb_helper->lock);
 314
 315         ret = drm_client_buffer_vmap(buffer, &map);
 316         if (ret)
 317                 goto out;
 318
 319         dst = map;
 320         drm_fbdev_damage_blit_real(fb_helper, clip, &dst);
 321
 322         drm_client_buffer_vunmap(buffer);
 323
 324 out:
 325         mutex_unlock(&fb_helper->lock);
 326
 327         return ret;
 328 }
 329
 330 static int drm_fbdev_fb_dirty(struct drm_fb_helper *helper, struct drm_clip_rect *clip)
 331 {
 332         struct drm_device *dev = helper->dev;
 333         int ret;
 334
 335         if (!drm_fbdev_use_shadow_fb(helper))
 336                 return 0;
 337
 338         /* Call damage handlers only if necessary */
 339         if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
 340                 return 0;
 341
 342         if (helper->buffer) {
 343                 ret = drm_fbdev_damage_blit(helper, clip);
 344                 if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
 345                         return ret;
 346         }
 347
 348         if (helper->fb->funcs->dirty) {
 349                 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
 350                 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
 351                         return ret;
 352         }
 353
 354         return 0;
 355 }
 356
 357 static const struct drm_fb_helper_funcs drm_fb_helper_generic_funcs = {
 358         .fb_probe = drm_fbdev_fb_probe,
 359         .fb_dirty = drm_fbdev_fb_dirty,
 360 };
 361
 362 static void drm_fbdev_client_unregister(struct drm_client_dev *client)
 363 {
 364         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 365
 366         if (fb_helper->info)
 367                 /* drm_fbdev_fb_destroy() takes care of cleanup */
 368                 drm_fb_helper_unregister_info(fb_helper);
 369         else
 370                 drm_fbdev_release(fb_helper);
 371 }
 372
 373 static int drm_fbdev_client_restore(struct drm_client_dev *client)
 374 {
 375         drm_fb_helper_lastclose(client->dev);
 376
 377         return 0;
 378 }
 379
 380 static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
 381 {
 382         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 383         struct drm_device *dev = client->dev;
 384         int ret;
 385
 386         /* Setup is not retried if it has failed */
 387         if (!fb_helper->dev && fb_helper->funcs)
 388                 return 0;
 389
 390         if (dev->fb_helper)
 391                 return drm_fb_helper_hotplug_event(dev->fb_helper);
 392
 393         if (!dev->mode_config.num_connector) {
 394                 drm_dbg_kms(dev, "No connectors found, will not create framebuffer!\n");
 395                 return 0;
 396         }
 397
 398         drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);
 399
 400         ret = drm_fb_helper_init(dev, fb_helper);
 401         if (ret)
 402                 goto err;
 403
 404         if (!drm_drv_uses_atomic_modeset(dev))
 405                 drm_helper_disable_unused_functions(dev);
 406
 407         ret = drm_fb_helper_initial_config(fb_helper, fb_helper->preferred_bpp);
 408         if (ret)
 409                 goto err_cleanup;
 410
 411         return 0;
 412
 413 err_cleanup:
 414         drm_fbdev_cleanup(fb_helper);
 415 err:
 416         fb_helper->dev = NULL;
 417         fb_helper->info = NULL;
 418
 419         drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret);
 420
 421         return ret;
 422 }
 423
 424 static const struct drm_client_funcs drm_fbdev_client_funcs = {
 425         .owner          = THIS_MODULE,
 426         .unregister     = drm_fbdev_client_unregister,
 427         .restore        = drm_fbdev_client_restore,
 428         .hotplug        = drm_fbdev_client_hotplug,
 429 };
 430
 431 /**
 432  * drm_fbdev_generic_setup() - Setup generic fbdev emulation
 433  * @dev: DRM device
 434  * @preferred_bpp: Preferred bits per pixel for the device.
 435  *                 @dev->mode_config.preferred_depth is used if this is zero.
 436  *
 437  * This function sets up generic fbdev emulation for drivers that supports
 438  * dumb buffers with a virtual address and that can be mmap'ed.
 439  * drm_fbdev_generic_setup() shall be called after the DRM driver registered
 440  * the new DRM device with drm_dev_register().
 441  *
 442  * Restore, hotplug events and teardown are all taken care of. Drivers that do
 443  * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
 444  * Simple drivers might use drm_mode_config_helper_suspend().
 445  *
 446  * Drivers that set the dirty callback on their framebuffer will get a shadow
 447  * fbdev buffer that is blitted onto the real buffer. This is done in order to
 448  * make deferred I/O work with all kinds of buffers. A shadow buffer can be
 449  * requested explicitly by setting struct drm_mode_config.prefer_shadow or
 450  * struct drm_mode_config.prefer_shadow_fbdev to true beforehand. This is
 451  * required to use generic fbdev emulation with SHMEM helpers.
 452  *
 453  * This function is safe to call even when there are no connectors present.
 454  * Setup will be retried on the next hotplug event.
 455  *
 456  * The fbdev is destroyed by drm_dev_unregister().
 457  */
 458 void drm_fbdev_generic_setup(struct drm_device *dev,
 459                              unsigned int preferred_bpp)
 460 {
 461         struct drm_fb_helper *fb_helper;
 462         int ret;
 463
 464         drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
 465         drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
 466
 467         fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
 468         if (!fb_helper)
 469                 return;
 470
 471         ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);
 472         if (ret) {
 473                 kfree(fb_helper);
 474                 drm_err(dev, "Failed to register client: %d\n", ret);
 475                 return;
 476         }
 477
 478         /*
 479          * FIXME: This mixes up depth with bpp, which results in a glorious
 480          * mess, resulting in some drivers picking wrong fbdev defaults and
 481          * others wrong preferred_depth defaults.
 482          */
 483         if (!preferred_bpp)
 484                 preferred_bpp = dev->mode_config.preferred_depth;
 485         if (!preferred_bpp)
 486                 preferred_bpp = 32;
 487         fb_helper->preferred_bpp = preferred_bpp;
 488
 489         ret = drm_fbdev_client_hotplug(&fb_helper->client);
 490         if (ret)
 491                 drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);
 492
 493         drm_client_register(&fb_helper->client);
 494 }
 495 EXPORT_SYMBOL(drm_fbdev_generic_setup);