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