drivers/gpu/drm/drm_fbdev_dma.c

   1 // SPDX-License-Identifier: MIT
   2
   3 #include <linux/fb.h>
   4
   5 #include <drm/drm_drv.h>
   6 #include <drm/drm_fbdev_dma.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 /*
  13  * struct fb_ops
  14  */
  15
  16 static int drm_fbdev_dma_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_dma_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 static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  38 {
  39         struct drm_fb_helper *fb_helper = info->par;
  40
  41         return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
  42 }
  43
  44 static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
  45 {
  46         struct drm_fb_helper *fb_helper = info->par;
  47
  48         if (!fb_helper->dev)
  49                 return;
  50
  51         if (info->fbdefio)
  52                 fb_deferred_io_cleanup(info);
  53         drm_fb_helper_fini(fb_helper);
  54
  55         drm_client_buffer_vunmap(fb_helper->buffer);
  56         drm_client_framebuffer_delete(fb_helper->buffer);
  57         drm_client_release(&fb_helper->client);
  58         drm_fb_helper_unprepare(fb_helper);
  59         kfree(fb_helper);
  60 }
  61
  62 static const struct fb_ops drm_fbdev_dma_fb_ops = {
  63         .owner = THIS_MODULE,
  64         .fb_open = drm_fbdev_dma_fb_open,
  65         .fb_release = drm_fbdev_dma_fb_release,
  66         __FB_DEFAULT_DMAMEM_OPS_RDWR,
  67         DRM_FB_HELPER_DEFAULT_OPS,
  68         __FB_DEFAULT_DMAMEM_OPS_DRAW,
  69         .fb_mmap = drm_fbdev_dma_fb_mmap,
  70         .fb_destroy = drm_fbdev_dma_fb_destroy,
  71 };
  72
  73 FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(drm_fbdev_dma,
  74                                    drm_fb_helper_damage_range,
  75                                    drm_fb_helper_damage_area);
  76
  77 static int drm_fbdev_dma_deferred_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
  78 {
  79         struct drm_fb_helper *fb_helper = info->par;
  80         struct drm_framebuffer *fb = fb_helper->fb;
  81         struct drm_gem_dma_object *dma = drm_fb_dma_get_gem_obj(fb, 0);
  82
  83         if (!dma->map_noncoherent)
  84                 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
  85
  86         return fb_deferred_io_mmap(info, vma);
  87 }
  88
  89 static const struct fb_ops drm_fbdev_dma_deferred_fb_ops = {
  90         .owner = THIS_MODULE,
  91         .fb_open = drm_fbdev_dma_fb_open,
  92         .fb_release = drm_fbdev_dma_fb_release,
  93         __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_dma),
  94         DRM_FB_HELPER_DEFAULT_OPS,
  95         __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_dma),
  96         .fb_mmap = drm_fbdev_dma_deferred_fb_mmap,
  97         .fb_destroy = drm_fbdev_dma_fb_destroy,
  98 };
  99
 100 /*
 101  * struct drm_fb_helper
 102  */
 103
 104 static int drm_fbdev_dma_helper_fb_dirty(struct drm_fb_helper *helper,
 105                                          struct drm_clip_rect *clip)
 106 {
 107         struct drm_device *dev = helper->dev;
 108         int ret;
 109
 110         /* Call damage handlers only if necessary */
 111         if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
 112                 return 0;
 113
 114         if (helper->fb->funcs->dirty) {
 115                 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
 116                 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
 117                         return ret;
 118         }
 119
 120         return 0;
 121 }
 122
 123 static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
 124         .fb_dirty = drm_fbdev_dma_helper_fb_dirty,
 125 };
 126
 127 /*
 128  * struct drm_fb_helper
 129  */
 130
 131 int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 132                                      struct drm_fb_helper_surface_size *sizes)
 133 {
 134         struct drm_client_dev *client = &fb_helper->client;
 135         struct drm_device *dev = fb_helper->dev;
 136         bool use_deferred_io = false;
 137         struct drm_client_buffer *buffer;
 138         struct drm_gem_dma_object *dma_obj;
 139         struct drm_framebuffer *fb;
 140         struct fb_info *info;
 141         u32 format;
 142         struct iosys_map map;
 143         int ret;
 144
 145         drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
 146                     sizes->surface_width, sizes->surface_height,
 147                     sizes->surface_bpp);
 148
 149         format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp,
 150                                              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         dma_obj = to_drm_gem_dma_obj(buffer->gem);
 156
 157         fb = buffer->fb;
 158
 159         /*
 160          * Deferred I/O requires struct page for framebuffer memory,
 161          * which is not guaranteed for all DMA ranges. We thus only
 162          * install deferred I/O if we have a framebuffer that requires
 163          * it.
 164          */
 165         if (fb->funcs->dirty)
 166                 use_deferred_io = true;
 167
 168         ret = drm_client_buffer_vmap(buffer, &map);
 169         if (ret) {
 170                 goto err_drm_client_buffer_delete;
 171         } else if (drm_WARN_ON(dev, map.is_iomem)) {
 172                 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
 173                 goto err_drm_client_buffer_delete;
 174         }
 175
 176         fb_helper->funcs = &drm_fbdev_dma_helper_funcs;
 177         fb_helper->buffer = buffer;
 178         fb_helper->fb = fb;
 179
 180         info = drm_fb_helper_alloc_info(fb_helper);
 181         if (IS_ERR(info)) {
 182                 ret = PTR_ERR(info);
 183                 goto err_drm_client_buffer_vunmap;
 184         }
 185
 186         drm_fb_helper_fill_info(info, fb_helper, sizes);
 187
 188         if (use_deferred_io)
 189                 info->fbops = &drm_fbdev_dma_deferred_fb_ops;
 190         else
 191                 info->fbops = &drm_fbdev_dma_fb_ops;
 192
 193         /* screen */
 194         info->flags |= FBINFO_VIRTFB; /* system memory */
 195         if (dma_obj->map_noncoherent)
 196                 info->flags |= FBINFO_READS_FAST; /* signal caching */
 197         info->screen_size = sizes->surface_height * fb->pitches[0];
 198         info->screen_buffer = map.vaddr;
 199         if (!(info->flags & FBINFO_HIDE_SMEM_START)) {
 200                 if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer)))
 201                         info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
 202         }
 203         info->fix.smem_len = info->screen_size;
 204
 205         /*
 206          * Only set up deferred I/O if the screen buffer supports
 207          * it. If this disagrees with the previous test for ->dirty,
 208          * mmap on the /dev/fb file might not work correctly.
 209          */
 210         if (!is_vmalloc_addr(info->screen_buffer) && info->fix.smem_start) {
 211                 unsigned long pfn = info->fix.smem_start >> PAGE_SHIFT;
 212
 213                 if (drm_WARN_ON(dev, !pfn_to_page(pfn)))
 214                         use_deferred_io = false;
 215         }
 216
 217         /* deferred I/O */
 218         if (use_deferred_io) {
 219                 fb_helper->fbdefio.delay = HZ / 20;
 220                 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
 221
 222                 info->fbdefio = &fb_helper->fbdefio;
 223                 ret = fb_deferred_io_init(info);
 224                 if (ret)
 225                         goto err_drm_fb_helper_release_info;
 226         }
 227
 228         return 0;
 229
 230 err_drm_fb_helper_release_info:
 231         drm_fb_helper_release_info(fb_helper);
 232 err_drm_client_buffer_vunmap:
 233         fb_helper->fb = NULL;
 234         fb_helper->buffer = NULL;
 235         drm_client_buffer_vunmap(buffer);
 236 err_drm_client_buffer_delete:
 237         drm_client_framebuffer_delete(buffer);
 238         return ret;
 239 }
 240 EXPORT_SYMBOL(drm_fbdev_dma_driver_fbdev_probe);