drivers/gpu/drm/drm_fbdev_dma.c

   1 // SPDX-License-Identifier: MIT
   2
   3 #include <drm/drm_crtc_helper.h>
   4 #include <drm/drm_drv.h>
   5 #include <drm/drm_fb_helper.h>
   6 #include <drm/drm_framebuffer.h>
   7 #include <drm/drm_gem_dma_helper.h>
   8
   9 #include <drm/drm_fbdev_dma.h>
  10
  11 /*
  12  * struct fb_ops
  13  */
  14
  15 static int drm_fbdev_dma_fb_open(struct fb_info *info, int user)
  16 {
  17         struct drm_fb_helper *fb_helper = info->par;
  18
  19         /* No need to take a ref for fbcon because it unbinds on unregister */
  20         if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
  21                 return -ENODEV;
  22
  23         return 0;
  24 }
  25
  26 static int drm_fbdev_dma_fb_release(struct fb_info *info, int user)
  27 {
  28         struct drm_fb_helper *fb_helper = info->par;
  29
  30         if (user)
  31                 module_put(fb_helper->dev->driver->fops->owner);
  32
  33         return 0;
  34 }
  35
  36 static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
  37 {
  38         struct drm_fb_helper *fb_helper = info->par;
  39
  40         if (!fb_helper->dev)
  41                 return;
  42
  43         drm_fb_helper_fini(fb_helper);
  44
  45         drm_client_buffer_vunmap(fb_helper->buffer);
  46         drm_client_framebuffer_delete(fb_helper->buffer);
  47         drm_client_release(&fb_helper->client);
  48         drm_fb_helper_unprepare(fb_helper);
  49         kfree(fb_helper);
  50 }
  51
  52 static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  53 {
  54         struct drm_fb_helper *fb_helper = info->par;
  55         struct drm_device *dev = fb_helper->dev;
  56
  57         if (drm_WARN_ON_ONCE(dev, !fb_helper->dev->driver->gem_prime_mmap))
  58                 return -ENODEV;
  59
  60         return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma);
  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_read = drm_fb_helper_sys_read,
  68         .fb_write = drm_fb_helper_sys_write,
  69         DRM_FB_HELPER_DEFAULT_OPS,
  70         .fb_fillrect = drm_fb_helper_sys_fillrect,
  71         .fb_copyarea = drm_fb_helper_sys_copyarea,
  72         .fb_imageblit = drm_fb_helper_sys_imageblit,
  73         .fb_destroy = drm_fbdev_dma_fb_destroy,
  74         .fb_mmap = drm_fbdev_dma_fb_mmap,
  75 };
  76
  77 /*
  78  * struct drm_fb_helper
  79  */
  80
  81 static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper,
  82                                          struct drm_fb_helper_surface_size *sizes)
  83 {
  84         struct drm_client_dev *client = &fb_helper->client;
  85         struct drm_device *dev = fb_helper->dev;
  86         struct drm_client_buffer *buffer;
  87         struct drm_gem_dma_object *dma_obj;
  88         struct drm_framebuffer *fb;
  89         struct fb_info *info;
  90         u32 format;
  91         struct iosys_map map;
  92         int ret;
  93
  94         drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
  95                     sizes->surface_width, sizes->surface_height,
  96                     sizes->surface_bpp);
  97
  98         format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
  99         buffer = drm_client_framebuffer_create(client, sizes->surface_width,
 100                                                sizes->surface_height, format);
 101         if (IS_ERR(buffer))
 102                 return PTR_ERR(buffer);
 103         dma_obj = to_drm_gem_dma_obj(buffer->gem);
 104
 105         fb = buffer->fb;
 106         if (drm_WARN_ON(dev, fb->funcs->dirty)) {
 107                 ret = -ENODEV; /* damage handling not supported; use generic emulation */
 108                 goto err_drm_client_buffer_delete;
 109         }
 110
 111         ret = drm_client_buffer_vmap(buffer, &map);
 112         if (ret) {
 113                 goto err_drm_client_buffer_delete;
 114         } else if (drm_WARN_ON(dev, map.is_iomem)) {
 115                 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
 116                 goto err_drm_client_buffer_delete;
 117         }
 118
 119         fb_helper->buffer = buffer;
 120         fb_helper->fb = buffer->fb;
 121
 122         info = drm_fb_helper_alloc_info(fb_helper);
 123         if (IS_ERR(info)) {
 124                 ret = PTR_ERR(info);
 125                 goto err_drm_client_buffer_vunmap;
 126         }
 127
 128         drm_fb_helper_fill_info(info, fb_helper, sizes);
 129
 130         info->fbops = &drm_fbdev_dma_fb_ops;
 131         info->flags = FBINFO_DEFAULT;
 132
 133         /* screen */
 134         info->flags |= FBINFO_VIRTFB; /* system memory */
 135         if (dma_obj->map_noncoherent)
 136                 info->flags |= FBINFO_READS_FAST; /* signal caching */
 137         info->screen_size = sizes->surface_height * fb->pitches[0];
 138         info->screen_buffer = map.vaddr;
 139         info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
 140         info->fix.smem_len = info->screen_size;
 141
 142         return 0;
 143
 144 err_drm_client_buffer_vunmap:
 145         fb_helper->fb = NULL;
 146         fb_helper->buffer = NULL;
 147         drm_client_buffer_vunmap(buffer);
 148 err_drm_client_buffer_delete:
 149         drm_client_framebuffer_delete(buffer);
 150         return ret;
 151 }
 152
 153 static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
 154         .fb_probe = drm_fbdev_dma_helper_fb_probe,
 155 };
 156
 157 /*
 158  * struct drm_client_funcs
 159  */
 160
 161 static void drm_fbdev_dma_client_unregister(struct drm_client_dev *client)
 162 {
 163         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 164
 165         if (fb_helper->info) {
 166                 drm_fb_helper_unregister_info(fb_helper);
 167         } else {
 168                 drm_client_release(&fb_helper->client);
 169                 drm_fb_helper_unprepare(fb_helper);
 170                 kfree(fb_helper);
 171         }
 172 }
 173
 174 static int drm_fbdev_dma_client_restore(struct drm_client_dev *client)
 175 {
 176         drm_fb_helper_lastclose(client->dev);
 177
 178         return 0;
 179 }
 180
 181 static int drm_fbdev_dma_client_hotplug(struct drm_client_dev *client)
 182 {
 183         struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 184         struct drm_device *dev = client->dev;
 185         int ret;
 186
 187         if (dev->fb_helper)
 188                 return drm_fb_helper_hotplug_event(dev->fb_helper);
 189
 190         ret = drm_fb_helper_init(dev, fb_helper);
 191         if (ret)
 192                 goto err_drm_err;
 193
 194         if (!drm_drv_uses_atomic_modeset(dev))
 195                 drm_helper_disable_unused_functions(dev);
 196
 197         ret = drm_fb_helper_initial_config(fb_helper);
 198         if (ret)
 199                 goto err_drm_fb_helper_fini;
 200
 201         return 0;
 202
 203 err_drm_fb_helper_fini:
 204         drm_fb_helper_fini(fb_helper);
 205 err_drm_err:
 206         drm_err(dev, "fbdev-dma: Failed to setup generic emulation (ret=%d)\n", ret);
 207         return ret;
 208 }
 209
 210 static const struct drm_client_funcs drm_fbdev_dma_client_funcs = {
 211         .owner          = THIS_MODULE,
 212         .unregister     = drm_fbdev_dma_client_unregister,
 213         .restore        = drm_fbdev_dma_client_restore,
 214         .hotplug        = drm_fbdev_dma_client_hotplug,
 215 };
 216
 217 /**
 218  * drm_fbdev_dma_setup() - Setup fbdev emulation for GEM DMA helpers
 219  * @dev: DRM device
 220  * @preferred_bpp: Preferred bits per pixel for the device.
 221  *                 @dev->mode_config.preferred_depth is used if this is zero.
 222  *
 223  * This function sets up fbdev emulation for GEM DMA drivers that support
 224  * dumb buffers with a virtual address and that can be mmap'ed.
 225  * drm_fbdev_dma_setup() shall be called after the DRM driver registered
 226  * the new DRM device with drm_dev_register().
 227  *
 228  * Restore, hotplug events and teardown are all taken care of. Drivers that do
 229  * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
 230  * Simple drivers might use drm_mode_config_helper_suspend().
 231  *
 232  * This function is safe to call even when there are no connectors present.
 233  * Setup will be retried on the next hotplug event.
 234  *
 235  * The fbdev is destroyed by drm_dev_unregister().
 236  */
 237 void drm_fbdev_dma_setup(struct drm_device *dev, unsigned int preferred_bpp)
 238 {
 239         struct drm_fb_helper *fb_helper;
 240         int ret;
 241
 242         drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
 243         drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
 244
 245         fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
 246         if (!fb_helper)
 247                 return;
 248         drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_dma_helper_funcs);
 249
 250         ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_dma_client_funcs);
 251         if (ret) {
 252                 drm_err(dev, "Failed to register client: %d\n", ret);
 253                 goto err_drm_client_init;
 254         }
 255
 256         ret = drm_fbdev_dma_client_hotplug(&fb_helper->client);
 257         if (ret)
 258                 drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);
 259
 260         drm_client_register(&fb_helper->client);
 261
 262         return;
 263
 264 err_drm_client_init:
 265         drm_fb_helper_unprepare(fb_helper);
 266         kfree(fb_helper);
 267 }
 268 EXPORT_SYMBOL(drm_fbdev_dma_setup);