drivers/gpu/drm/drm_fbdev_shmem.c

   1 // SPDX-License-Identifier: MIT
   2
   3 #include <linux/fb.h>
   4
   5 #include <drm/drm_drv.h>
   6 #include <drm/drm_fbdev_shmem.h>
   7 #include <drm/drm_fb_helper.h>
   8 #include <drm/drm_framebuffer.h>
   9 #include <drm/drm_gem_framebuffer_helper.h>
  10 #include <drm/drm_gem_shmem_helper.h>
  11
  12 /*
  13  * struct fb_ops
  14  */
  15
  16 static int drm_fbdev_shmem_fb_open(struct fb_info *info, int user)
  17 {
  18         struct drm_fb_helper *fb_helper = info->par;
  19
  20         /* No need to take a ref for fbcon because it unbinds on unregister */
  21         if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
  22                 return -ENODEV;
  23
  24         return 0;
  25 }
  26
  27 static int drm_fbdev_shmem_fb_release(struct fb_info *info, int user)
  28 {
  29         struct drm_fb_helper *fb_helper = info->par;
  30
  31         if (user)
  32                 module_put(fb_helper->dev->driver->fops->owner);
  33
  34         return 0;
  35 }
  36
  37 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_shmem,
  38                                    drm_fb_helper_damage_range,
  39                                    drm_fb_helper_damage_area);
  40
  41 static int drm_fbdev_shmem_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  42 {
  43         struct drm_fb_helper *fb_helper = info->par;
  44         struct drm_framebuffer *fb = fb_helper->fb;
  45         struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, 0);
  46         struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
  47
  48         if (shmem->map_wc)
  49                 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
  50
  51         return fb_deferred_io_mmap(info, vma);
  52 }
  53
  54 static void drm_fbdev_shmem_fb_destroy(struct fb_info *info)
  55 {
  56         struct drm_fb_helper *fb_helper = info->par;
  57
  58         if (!fb_helper->dev)
  59                 return;
  60
  61         fb_deferred_io_cleanup(info);
  62         drm_fb_helper_fini(fb_helper);
  63
  64         drm_client_buffer_vunmap(fb_helper->buffer);
  65         drm_client_framebuffer_delete(fb_helper->buffer);
  66         drm_client_release(&fb_helper->client);
  67         drm_fb_helper_unprepare(fb_helper);
  68         kfree(fb_helper);
  69 }
  70
  71 static const struct fb_ops drm_fbdev_shmem_fb_ops = {
  72         .owner = THIS_MODULE,
  73         .fb_open = drm_fbdev_shmem_fb_open,
  74         .fb_release = drm_fbdev_shmem_fb_release,
  75         __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_shmem),
  76         DRM_FB_HELPER_DEFAULT_OPS,
  77         __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_shmem),
  78         .fb_mmap = drm_fbdev_shmem_fb_mmap,
  79         .fb_destroy = drm_fbdev_shmem_fb_destroy,
  80 };
  81
  82 static struct page *drm_fbdev_shmem_get_page(struct fb_info *info, unsigned long offset)
  83 {
  84         struct drm_fb_helper *fb_helper = info->par;
  85         struct drm_framebuffer *fb = fb_helper->fb;
  86         struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, 0);
  87         struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
  88         unsigned int i = offset >> PAGE_SHIFT;
  89         struct page *page;
  90
  91         if (fb_WARN_ON_ONCE(info, offset > obj->size))
  92                 return NULL;
  93
  94         page = shmem->pages[i]; // protected by active vmap
  95         if (page)
  96                 get_page(page);
  97         fb_WARN_ON_ONCE(info, !page);
  98
  99         return page;
 100 }
 101
 102 /*
 103  * struct drm_fb_helper
 104  */
 105
 106 static int drm_fbdev_shmem_helper_fb_dirty(struct drm_fb_helper *helper,
 107                                            struct drm_clip_rect *clip)
 108 {
 109         struct drm_device *dev = helper->dev;
 110         int ret;
 111
 112         /* Call damage handlers only if necessary */
 113         if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
 114                 return 0;
 115
 116         if (helper->fb->funcs->dirty) {
 117                 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
 118                 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
 119                         return ret;
 120         }
 121
 122         return 0;
 123 }
 124
 125 static const struct drm_fb_helper_funcs drm_fbdev_shmem_helper_funcs = {
 126         .fb_dirty = drm_fbdev_shmem_helper_fb_dirty,
 127 };
 128
 129 /*
 130  * struct drm_driver
 131  */
 132
 133 int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 134                                        struct drm_fb_helper_surface_size *sizes)
 135 {
 136         struct drm_client_dev *client = &fb_helper->client;
 137         struct drm_device *dev = fb_helper->dev;
 138         struct drm_client_buffer *buffer;
 139         struct drm_gem_shmem_object *shmem;
 140         struct drm_framebuffer *fb;
 141         struct fb_info *info;
 142         u32 format;
 143         struct iosys_map map;
 144         int ret;
 145
 146         drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
 147                     sizes->surface_width, sizes->surface_height,
 148                     sizes->surface_bpp);
 149
 150         format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp, sizes->surface_depth);
 151         buffer = drm_client_framebuffer_create(client, sizes->surface_width,
 152                                                sizes->surface_height, format);
 153         if (IS_ERR(buffer))
 154                 return PTR_ERR(buffer);
 155         shmem = to_drm_gem_shmem_obj(buffer->gem);
 156
 157         fb = buffer->fb;
 158
 159         ret = drm_client_buffer_vmap(buffer, &map);
 160         if (ret) {
 161                 goto err_drm_client_buffer_delete;
 162         } else if (drm_WARN_ON(dev, map.is_iomem)) {
 163                 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
 164                 goto err_drm_client_buffer_delete;
 165         }
 166
 167         fb_helper->funcs = &drm_fbdev_shmem_helper_funcs;
 168         fb_helper->buffer = buffer;
 169         fb_helper->fb = fb;
 170
 171         info = drm_fb_helper_alloc_info(fb_helper);
 172         if (IS_ERR(info)) {
 173                 ret = PTR_ERR(info);
 174                 goto err_drm_client_buffer_vunmap;
 175         }
 176
 177         drm_fb_helper_fill_info(info, fb_helper, sizes);
 178
 179         info->fbops = &drm_fbdev_shmem_fb_ops;
 180
 181         /* screen */
 182         info->flags |= FBINFO_VIRTFB; /* system memory */
 183         if (!shmem->map_wc)
 184                 info->flags |= FBINFO_READS_FAST; /* signal caching */
 185         info->screen_size = sizes->surface_height * fb->pitches[0];
 186         info->screen_buffer = map.vaddr;
 187         info->fix.smem_len = info->screen_size;
 188
 189         /* deferred I/O */
 190         fb_helper->fbdefio.delay = HZ / 20;
 191         fb_helper->fbdefio.get_page = drm_fbdev_shmem_get_page;
 192         fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
 193
 194         info->fbdefio = &fb_helper->fbdefio;
 195         ret = fb_deferred_io_init(info);
 196         if (ret)
 197                 goto err_drm_fb_helper_release_info;
 198
 199         return 0;
 200
 201 err_drm_fb_helper_release_info:
 202         drm_fb_helper_release_info(fb_helper);
 203 err_drm_client_buffer_vunmap:
 204         fb_helper->fb = NULL;
 205         fb_helper->buffer = NULL;
 206         drm_client_buffer_vunmap(buffer);
 207 err_drm_client_buffer_delete:
 208         drm_client_framebuffer_delete(buffer);
 209         return ret;
 210 }
 211 EXPORT_SYMBOL(drm_fbdev_shmem_driver_fbdev_probe);