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