drivers/gpu/drm/drm_fbdev_dma.c

   1 // SPDX-License-Identifier: MIT
   2
   3 #include <linux/fb.h>
   4
   5 #include <drm/drm_crtc_helper.h>
   6 #include <drm/drm_drv.h>
   7 #include <drm/drm_fb_dma_helper.h>
   8 #include <drm/drm_fb_helper.h>
   9 #include <drm/drm_framebuffer.h>
  10 #include <drm/drm_gem_dma_helper.h>
  11
  12 #include <drm/drm_fbdev_dma.h>
  13
  14 /*
  15  * struct fb_ops
  16  */
  17
  18 static int drm_fbdev_dma_fb_open(struct fb_info *info, int user)
  19 {
  20         struct drm_fb_helper *fb_helper = info->par;
  21
  22         /* No need to take a ref for fbcon because it unbinds on unregister */
  23         if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
  24                 return -ENODEV;
  25
  26         return 0;
  27 }
  28
  29 static int drm_fbdev_dma_fb_release(struct fb_info *info, int user)
  30 {
  31         struct drm_fb_helper *fb_helper = info->par;
  32
  33         if (user)
  34                 module_put(fb_helper->dev->driver->fops->owner);
  35
  36         return 0;
  37 }
  38
  39 static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  40 {
  41         struct drm_fb_helper *fb_helper = info->par;
  42
  43         return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
  44 }
  45
  46 static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
  47 {
  48         struct drm_fb_helper *fb_helper = info->par;
  49
  50         if (!fb_helper->dev)
  51                 return;
  52
  53         fb_deferred_io_cleanup(info);
  54         drm_fb_helper_fini(fb_helper);
  55
  56         drm_client_buffer_vunmap(fb_helper->buffer);
  57         drm_client_framebuffer_delete(fb_helper->buffer);
  58         drm_client_release(&fb_helper->client);
  59         drm_fb_helper_unprepare(fb_helper);
  60         kfree(fb_helper);
  61 }
  62
  63 static const struct fb_ops drm_fbdev_dma_fb_ops = {
  64         .owner = THIS_MODULE,
  65         .fb_open = drm_fbdev_dma_fb_open,
  66         .fb_release = drm_fbdev_dma_fb_release,
  67         __FB_DEFAULT_DMAMEM_OPS_RDWR,
  68         DRM_FB_HELPER_DEFAULT_OPS,
  69         __FB_DEFAULT_DMAMEM_OPS_DRAW,
  70         .fb_mmap = drm_fbdev_dma_fb_mmap,
  71         .fb_destroy = drm_fbdev_dma_fb_destroy,
  72 };
  73
  74 FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(drm_fbdev_dma,
  75                                    drm_fb_helper_damage_range,
  76                                    drm_fb_helper_damage_area);
  77
  78 static int drm_fbdev_dma_deferred_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  79 {
  80         struct drm_fb_helper *fb_helper = info->par;
  81         struct drm_framebuffer *fb = fb_helper->fb;
  82         struct drm_gem_dma_object *dma = drm_fb_dma_get_gem_obj(fb, 0);
  83
  84         if (!dma->map_noncoherent)
  85                 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
  86
  87         return fb_deferred_io_mmap(info, vma);
  88 }
  89
  90 static const struct fb_ops drm_fbdev_dma_deferred_fb_ops = {
  91         .owner = THIS_MODULE,
  92         .fb_open = drm_fbdev_dma_fb_open,
  93         .fb_release = drm_fbdev_dma_fb_release,
  94         __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_dma),
  95         DRM_FB_HELPER_DEFAULT_OPS,
  96         __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_dma),
  97         .fb_mmap = drm_fbdev_dma_deferred_fb_mmap,
  98         .fb_destroy = drm_fbdev_dma_fb_destroy,
  99 };
 100
 101 /*
 102  * struct drm_fb_helper
 103  */
 104
 105 static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper,
 106                                          struct drm_fb_helper_surface_size *sizes)
 107 {
 108         struct drm_client_dev *client = &fb_helper->client;
 109         struct drm_device *dev = fb_helper->dev;
 110         bool use_deferred_io = false;
 111         struct drm_client_buffer *buffer;
 112         struct drm_gem_dma_object *dma_obj;
 113         struct drm_framebuffer *fb;
 114         struct fb_info *info;
 115         u32 format;
 116         struct iosys_map map;
 117         int ret;
 118
 119         drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
 120                     sizes->surface_width, sizes->surface_height,
 121                     sizes->surface_bpp);
 122
 123         format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp,
 124                                              sizes->surface_depth);
 125         buffer = drm_client_framebuffer_create(client, sizes->surface_width,
 126                                                sizes->surface_height, format);
 127         if (IS_ERR(buffer))
 128                 return PTR_ERR(buffer);
 129         dma_obj = to_drm_gem_dma_obj(buffer->gem);
 130
 131         fb = buffer->fb;
 132
 133         /*
 134          * Deferred I/O requires struct page for framebuffer memory,
 135          * which is not guaranteed for all DMA ranges. We thus only
 136          * install deferred I/O if we have a framebuffer that requires
 137          * it.
 138          */
 139         if (fb->funcs->dirty)
 140                 use_deferred_io = true;
 141
 142         ret = drm_client_buffer_vmap(buffer, &map);
 143         if (ret) {
 144                 goto err_drm_client_buffer_delete;
 145         } else if (drm_WARN_ON(dev, map.is_iomem)) {
 146                 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
 147                 goto err_drm_client_buffer_delete;
 148         }
 149
 150         fb_helper->buffer = buffer;
 151         fb_helper->fb = fb;
 152
 153         info = drm_fb_helper_alloc_info(fb_helper);
 154         if (IS_ERR(info)) {
 155                 ret = PTR_ERR(info);
 156                 goto err_drm_client_buffer_vunmap;
 157         }
 158
 159         drm_fb_helper_fill_info(info, fb_helper, sizes);
 160
 161         if (use_deferred_io)
 162                 info->fbops = &drm_fbdev_dma_deferred_fb_ops;
 163         else
 164                 info->fbops = &drm_fbdev_dma_fb_ops;
 165
 166         /* screen */
 167         info->flags |= FBINFO_VIRTFB; /* system memory */
 168         if (dma_obj->map_noncoherent)
 169                 info->flags |= FBINFO_READS_FAST; /* signal caching */
 170         info->screen_size = sizes->surface_height * fb->pitches[0];
 171         info->screen_buffer = map.vaddr;
 172         if (!(info->flags & FBINFO_HIDE_SMEM_START)) {
 173                 if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer)))
 174                         info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
 175         }
 176         info->fix.smem_len = info->screen_size;
 177
 178         /*
 179          * Only set up deferred I/O if the screen buffer supports
 180          * it. If this disagrees with the previous test for ->dirty,
 181          * mmap on the /dev/fb file might not work correctly.
 182          */
 183         if (!is_vmalloc_addr(info->screen_buffer) && info->fix.smem_start) {
 184                 unsigned long pfn = info->fix.smem_start >> PAGE_SHIFT;
 185
 186                 if (drm_WARN_ON(dev, !pfn_to_page(pfn)))
 187                         use_deferred_io = false;
 188         }
 189
 190         /* deferred I/O */
 191         if (use_deferred_io) {
 192                 fb_helper->fbdefio.delay = HZ / 20;
 193                 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
 194
 195                 info->fbdefio = &fb_helper->fbdefio;
 196                 ret = fb_deferred_io_init(info);
 197                 if (ret)
 198                         goto err_drm_fb_helper_release_info;
 199         }
 200
 201         return 0;
 202
 203 err_drm_fb_helper_release_info:
 204         drm_fb_helper_release_info(fb_helper);
 205 err_drm_client_buffer_vunmap:
 206         fb_helper->fb = NULL;
 207         fb_helper->buffer = NULL;
 208         drm_client_buffer_vunmap(buffer);
 209 err_drm_client_buffer_delete:
 210         drm_client_framebuffer_delete(buffer);
 211         return ret;
 212 }
 213
 214 static int drm_fbdev_dma_helper_fb_dirty(struct drm_fb_helper *helper,
 215                                          struct drm_clip_rect *clip)
 216 {
 217         struct drm_device *dev = helper->dev;
 218         int ret;
 219
 220         /* Call damage handlers only if necessary */
 221         if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
 222                 return 0;
 223
 224         if (helper->fb->funcs->dirty) {
 225                 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
 226                 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
 227                         return ret;
 228         }
 229
 230         return 0;
 231 }
 232
 233 static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
 234         .fb_probe = drm_fbdev_dma_helper_fb_probe,
 235         .fb_dirty = drm_fbdev_dma_helper_fb_dirty,
 236 };
 237
 238 /*
 239  * struct drm_client_funcs
 240  */
 241
 242 static void drm_fbdev_dma_client_unregister(struct drm_client_dev *client)
 243 {
 244         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 245
 246         if (fb_helper->info) {
 247                 drm_fb_helper_unregister_info(fb_helper);
 248         } else {
 249                 drm_client_release(&fb_helper->client);
 250                 drm_fb_helper_unprepare(fb_helper);
 251                 kfree(fb_helper);
 252         }
 253 }
 254
 255 static int drm_fbdev_dma_client_restore(struct drm_client_dev *client)
 256 {
 257         drm_fb_helper_lastclose(client->dev);
 258
 259         return 0;
 260 }
 261
 262 static int drm_fbdev_dma_client_hotplug(struct drm_client_dev *client)
 263 {
 264         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 265         struct drm_device *dev = client->dev;
 266         int ret;
 267
 268         if (dev->fb_helper)
 269                 return drm_fb_helper_hotplug_event(dev->fb_helper);
 270
 271         ret = drm_fb_helper_init(dev, fb_helper);
 272         if (ret)
 273                 goto err_drm_err;
 274
 275         if (!drm_drv_uses_atomic_modeset(dev))
 276                 drm_helper_disable_unused_functions(dev);
 277
 278         ret = drm_fb_helper_initial_config(fb_helper);
 279         if (ret)
 280                 goto err_drm_fb_helper_fini;
 281
 282         return 0;
 283
 284 err_drm_fb_helper_fini:
 285         drm_fb_helper_fini(fb_helper);
 286 err_drm_err:
 287         drm_err(dev, "fbdev-dma: Failed to setup generic emulation (ret=%d)\n", ret);
 288         return ret;
 289 }
 290
 291 static const struct drm_client_funcs drm_fbdev_dma_client_funcs = {
 292         .owner          = THIS_MODULE,
 293         .unregister     = drm_fbdev_dma_client_unregister,
 294         .restore        = drm_fbdev_dma_client_restore,
 295         .hotplug        = drm_fbdev_dma_client_hotplug,
 296 };
 297
 298 /**
 299  * drm_fbdev_dma_setup() - Setup fbdev emulation for GEM DMA helpers
 300  * @dev: DRM device
 301  * @preferred_bpp: Preferred bits per pixel for the device.
 302  *                 32 is used if this is zero.
 303  *
 304  * This function sets up fbdev emulation for GEM DMA drivers that support
 305  * dumb buffers with a virtual address and that can be mmap'ed.
 306  * drm_fbdev_dma_setup() shall be called after the DRM driver registered
 307  * the new DRM device with drm_dev_register().
 308  *
 309  * Restore, hotplug events and teardown are all taken care of. Drivers that do
 310  * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
 311  * Simple drivers might use drm_mode_config_helper_suspend().
 312  *
 313  * This function is safe to call even when there are no connectors present.
 314  * Setup will be retried on the next hotplug event.
 315  *
 316  * The fbdev is destroyed by drm_dev_unregister().
 317  */
 318 void drm_fbdev_dma_setup(struct drm_device *dev, unsigned int preferred_bpp)
 319 {
 320         struct drm_fb_helper *fb_helper;
 321         int ret;
 322
 323         drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
 324         drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
 325
 326         fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
 327         if (!fb_helper)
 328                 return;
 329         drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_dma_helper_funcs);
 330
 331         ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_dma_client_funcs);
 332         if (ret) {
 333                 drm_err(dev, "Failed to register client: %d\n", ret);
 334                 goto err_drm_client_init;
 335         }
 336
 337         drm_client_register(&fb_helper->client);
 338
 339         return;
 340
 341 err_drm_client_init:
 342         drm_fb_helper_unprepare(fb_helper);
 343         kfree(fb_helper);
 344 }
 345 EXPORT_SYMBOL(drm_fbdev_dma_setup);