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_helper.h>
   8 #include <drm/drm_framebuffer.h>
   9 #include <drm/drm_gem_dma_helper.h>
  10
  11 #include <drm/drm_fbdev_dma.h>
  12
  13 /*
  14  * struct fb_ops
  15  */
  16
  17 static int drm_fbdev_dma_fb_open(struct fb_info *info, int user)
  18 {
  19         struct drm_fb_helper *fb_helper = info->par;
  20
  21         /* No need to take a ref for fbcon because it unbinds on unregister */
  22         if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
  23                 return -ENODEV;
  24
  25         return 0;
  26 }
  27
  28 static int drm_fbdev_dma_fb_release(struct fb_info *info, int user)
  29 {
  30         struct drm_fb_helper *fb_helper = info->par;
  31
  32         if (user)
  33                 module_put(fb_helper->dev->driver->fops->owner);
  34
  35         return 0;
  36 }
  37
  38 static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
  39 {
  40         struct drm_fb_helper *fb_helper = info->par;
  41
  42         if (!fb_helper->dev)
  43                 return;
  44
  45         drm_fb_helper_fini(fb_helper);
  46
  47         drm_client_buffer_vunmap(fb_helper->buffer);
  48         drm_client_framebuffer_delete(fb_helper->buffer);
  49         drm_client_release(&fb_helper->client);
  50         drm_fb_helper_unprepare(fb_helper);
  51         kfree(fb_helper);
  52 }
  53
  54 static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  55 {
  56         struct drm_fb_helper *fb_helper = info->par;
  57
  58         return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
  59 }
  60
  61 static const struct fb_ops drm_fbdev_dma_fb_ops = {
  62         .owner = THIS_MODULE,
  63         .fb_open = drm_fbdev_dma_fb_open,
  64         .fb_release = drm_fbdev_dma_fb_release,
  65         __FB_DEFAULT_DMAMEM_OPS_RDWR,
  66         DRM_FB_HELPER_DEFAULT_OPS,
  67         __FB_DEFAULT_DMAMEM_OPS_DRAW,
  68         .fb_mmap = drm_fbdev_dma_fb_mmap,
  69         .fb_destroy = drm_fbdev_dma_fb_destroy,
  70 };
  71
  72 /*
  73  * struct drm_fb_helper
  74  */
  75
  76 static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper,
  77                                          struct drm_fb_helper_surface_size *sizes)
  78 {
  79         struct drm_client_dev *client = &fb_helper->client;
  80         struct drm_device *dev = fb_helper->dev;
  81         struct drm_client_buffer *buffer;
  82         struct drm_gem_dma_object *dma_obj;
  83         struct drm_framebuffer *fb;
  84         struct fb_info *info;
  85         u32 format;
  86         struct iosys_map map;
  87         int ret;
  88
  89         drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
  90                     sizes->surface_width, sizes->surface_height,
  91                     sizes->surface_bpp);
  92
  93         format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
  94         buffer = drm_client_framebuffer_create(client, sizes->surface_width,
  95                                                sizes->surface_height, format);
  96         if (IS_ERR(buffer))
  97                 return PTR_ERR(buffer);
  98         dma_obj = to_drm_gem_dma_obj(buffer->gem);
  99
 100         fb = buffer->fb;
 101         if (drm_WARN_ON(dev, fb->funcs->dirty)) {
 102                 ret = -ENODEV; /* damage handling not supported; use generic emulation */
 103                 goto err_drm_client_buffer_delete;
 104         }
 105
 106         ret = drm_client_buffer_vmap(buffer, &map);
 107         if (ret) {
 108                 goto err_drm_client_buffer_delete;
 109         } else if (drm_WARN_ON(dev, map.is_iomem)) {
 110                 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
 111                 goto err_drm_client_buffer_delete;
 112         }
 113
 114         fb_helper->buffer = buffer;
 115         fb_helper->fb = buffer->fb;
 116
 117         info = drm_fb_helper_alloc_info(fb_helper);
 118         if (IS_ERR(info)) {
 119                 ret = PTR_ERR(info);
 120                 goto err_drm_client_buffer_vunmap;
 121         }
 122
 123         drm_fb_helper_fill_info(info, fb_helper, sizes);
 124
 125         info->fbops = &drm_fbdev_dma_fb_ops;
 126
 127         /* screen */
 128         info->flags |= FBINFO_VIRTFB; /* system memory */
 129         if (dma_obj->map_noncoherent)
 130                 info->flags |= FBINFO_READS_FAST; /* signal caching */
 131         info->screen_size = sizes->surface_height * fb->pitches[0];
 132         info->screen_buffer = map.vaddr;
 133         if (!(info->flags & FBINFO_HIDE_SMEM_START)) {
 134                 if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer)))
 135                         info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
 136         }
 137         info->fix.smem_len = info->screen_size;
 138
 139         return 0;
 140
 141 err_drm_client_buffer_vunmap:
 142         fb_helper->fb = NULL;
 143         fb_helper->buffer = NULL;
 144         drm_client_buffer_vunmap(buffer);
 145 err_drm_client_buffer_delete:
 146         drm_client_framebuffer_delete(buffer);
 147         return ret;
 148 }
 149
 150 static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
 151         .fb_probe = drm_fbdev_dma_helper_fb_probe,
 152 };
 153
 154 /*
 155  * struct drm_client_funcs
 156  */
 157
 158 static void drm_fbdev_dma_client_unregister(struct drm_client_dev *client)
 159 {
 160         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 161
 162         if (fb_helper->info) {
 163                 drm_fb_helper_unregister_info(fb_helper);
 164         } else {
 165                 drm_client_release(&fb_helper->client);
 166                 drm_fb_helper_unprepare(fb_helper);
 167                 kfree(fb_helper);
 168         }
 169 }
 170
 171 static int drm_fbdev_dma_client_restore(struct drm_client_dev *client)
 172 {
 173         drm_fb_helper_lastclose(client->dev);
 174
 175         return 0;
 176 }
 177
 178 static int drm_fbdev_dma_client_hotplug(struct drm_client_dev *client)
 179 {
 180         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 181         struct drm_device *dev = client->dev;
 182         int ret;
 183
 184         if (dev->fb_helper)
 185                 return drm_fb_helper_hotplug_event(dev->fb_helper);
 186
 187         ret = drm_fb_helper_init(dev, fb_helper);
 188         if (ret)
 189                 goto err_drm_err;
 190
 191         if (!drm_drv_uses_atomic_modeset(dev))
 192                 drm_helper_disable_unused_functions(dev);
 193
 194         ret = drm_fb_helper_initial_config(fb_helper);
 195         if (ret)
 196                 goto err_drm_fb_helper_fini;
 197
 198         return 0;
 199
 200 err_drm_fb_helper_fini:
 201         drm_fb_helper_fini(fb_helper);
 202 err_drm_err:
 203         drm_err(dev, "fbdev-dma: Failed to setup generic emulation (ret=%d)\n", ret);
 204         return ret;
 205 }
 206
 207 static const struct drm_client_funcs drm_fbdev_dma_client_funcs = {
 208         .owner          = THIS_MODULE,
 209         .unregister     = drm_fbdev_dma_client_unregister,
 210         .restore        = drm_fbdev_dma_client_restore,
 211         .hotplug        = drm_fbdev_dma_client_hotplug,
 212 };
 213
 214 /**
 215  * drm_fbdev_dma_setup() - Setup fbdev emulation for GEM DMA helpers
 216  * @dev: DRM device
 217  * @preferred_bpp: Preferred bits per pixel for the device.
 218  *                 32 is used if this is zero.
 219  *
 220  * This function sets up fbdev emulation for GEM DMA drivers that support
 221  * dumb buffers with a virtual address and that can be mmap'ed.
 222  * drm_fbdev_dma_setup() shall be called after the DRM driver registered
 223  * the new DRM device with drm_dev_register().
 224  *
 225  * Restore, hotplug events and teardown are all taken care of. Drivers that do
 226  * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
 227  * Simple drivers might use drm_mode_config_helper_suspend().
 228  *
 229  * This function is safe to call even when there are no connectors present.
 230  * Setup will be retried on the next hotplug event.
 231  *
 232  * The fbdev is destroyed by drm_dev_unregister().
 233  */
 234 void drm_fbdev_dma_setup(struct drm_device *dev, unsigned int preferred_bpp)
 235 {
 236         struct drm_fb_helper *fb_helper;
 237         int ret;
 238
 239         drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
 240         drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
 241
 242         fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
 243         if (!fb_helper)
 244                 return;
 245         drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_dma_helper_funcs);
 246
 247         ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_dma_client_funcs);
 248         if (ret) {
 249                 drm_err(dev, "Failed to register client: %d\n", ret);
 250                 goto err_drm_client_init;
 251         }
 252
 253         drm_client_register(&fb_helper->client);
 254
 255         return;
 256
 257 err_drm_client_init:
 258         drm_fb_helper_unprepare(fb_helper);
 259         kfree(fb_helper);
 260 }
 261 EXPORT_SYMBOL(drm_fbdev_dma_setup);