drivers/gpu/drm/drm_fbdev_ttm.c

   1 // SPDX-License-Identifier: MIT
   2
   3 #include <linux/moduleparam.h>
   4 #include <linux/vmalloc.h>
   5
   6 #include <drm/drm_crtc_helper.h>
   7 #include <drm/drm_drv.h>
   8 #include <drm/drm_fb_helper.h>
   9 #include <drm/drm_framebuffer.h>
  10 #include <drm/drm_gem.h>
  11 #include <drm/drm_print.h>
  12
  13 #include <drm/drm_fbdev_ttm.h>
  14
  15 /* @user: 1=userspace, 0=fbcon */
  16 static int drm_fbdev_ttm_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_ttm_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_ttm,
  38                                    drm_fb_helper_damage_range,
  39                                    drm_fb_helper_damage_area);
  40
  41 static void drm_fbdev_ttm_fb_destroy(struct fb_info *info)
  42 {
  43         struct drm_fb_helper *fb_helper = info->par;
  44         void *shadow = info->screen_buffer;
  45
  46         if (!fb_helper->dev)
  47                 return;
  48
  49         fb_deferred_io_cleanup(info);
  50         drm_fb_helper_fini(fb_helper);
  51         vfree(shadow);
  52         drm_client_framebuffer_delete(fb_helper->buffer);
  53
  54         drm_client_release(&fb_helper->client);
  55         drm_fb_helper_unprepare(fb_helper);
  56         kfree(fb_helper);
  57 }
  58
  59 static const struct fb_ops drm_fbdev_ttm_fb_ops = {
  60         .owner          = THIS_MODULE,
  61         .fb_open        = drm_fbdev_ttm_fb_open,
  62         .fb_release     = drm_fbdev_ttm_fb_release,
  63         FB_DEFAULT_DEFERRED_OPS(drm_fbdev_ttm),
  64         DRM_FB_HELPER_DEFAULT_OPS,
  65         .fb_destroy     = drm_fbdev_ttm_fb_destroy,
  66 };
  67
  68 static void drm_fbdev_ttm_damage_blit_real(struct drm_fb_helper *fb_helper,
  69                                            struct drm_clip_rect *clip,
  70                                            struct iosys_map *dst)
  71 {
  72         struct drm_framebuffer *fb = fb_helper->fb;
  73         size_t offset = clip->y1 * fb->pitches[0];
  74         size_t len = clip->x2 - clip->x1;
  75         unsigned int y;
  76         void *src;
  77
  78         switch (drm_format_info_bpp(fb->format, 0)) {
  79         case 1:
  80                 offset += clip->x1 / 8;
  81                 len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
  82                 break;
  83         case 2:
  84                 offset += clip->x1 / 4;
  85                 len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
  86                 break;
  87         case 4:
  88                 offset += clip->x1 / 2;
  89                 len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
  90                 break;
  91         default:
  92                 offset += clip->x1 * fb->format->cpp[0];
  93                 len *= fb->format->cpp[0];
  94                 break;
  95         }
  96
  97         src = fb_helper->info->screen_buffer + offset;
  98         iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
  99
 100         for (y = clip->y1; y < clip->y2; y++) {
 101                 iosys_map_memcpy_to(dst, 0, src, len);
 102                 iosys_map_incr(dst, fb->pitches[0]);
 103                 src += fb->pitches[0];
 104         }
 105 }
 106
 107 static int drm_fbdev_ttm_damage_blit(struct drm_fb_helper *fb_helper,
 108                                      struct drm_clip_rect *clip)
 109 {
 110         struct drm_client_buffer *buffer = fb_helper->buffer;
 111         struct iosys_map map, dst;
 112         int ret;
 113
 114         /*
 115          * We have to pin the client buffer to its current location while
 116          * flushing the shadow buffer. In the general case, concurrent
 117          * modesetting operations could try to move the buffer and would
 118          * fail. The modeset has to be serialized by acquiring the reservation
 119          * object of the underlying BO here.
 120          *
 121          * For fbdev emulation, we only have to protect against fbdev modeset
 122          * operations. Nothing else will involve the client buffer's BO. So it
 123          * is sufficient to acquire struct drm_fb_helper.lock here.
 124          */
 125         mutex_lock(&fb_helper->lock);
 126
 127         ret = drm_client_buffer_vmap_local(buffer, &map);
 128         if (ret)
 129                 goto out;
 130
 131         dst = map;
 132         drm_fbdev_ttm_damage_blit_real(fb_helper, clip, &dst);
 133
 134         drm_client_buffer_vunmap_local(buffer);
 135
 136 out:
 137         mutex_unlock(&fb_helper->lock);
 138
 139         return ret;
 140 }
 141
 142 static int drm_fbdev_ttm_helper_fb_dirty(struct drm_fb_helper *helper,
 143                                          struct drm_clip_rect *clip)
 144 {
 145         struct drm_device *dev = helper->dev;
 146         int ret;
 147
 148         /* Call damage handlers only if necessary */
 149         if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
 150                 return 0;
 151
 152         ret = drm_fbdev_ttm_damage_blit(helper, clip);
 153         if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
 154                 return ret;
 155
 156         if (helper->fb->funcs->dirty) {
 157                 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
 158                 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
 159                         return ret;
 160         }
 161
 162         return 0;
 163 }
 164
 165 static const struct drm_fb_helper_funcs drm_fbdev_ttm_helper_funcs = {
 166         .fb_dirty = drm_fbdev_ttm_helper_fb_dirty,
 167 };
 168
 169 /*
 170  * struct drm_driver
 171  */
 172
 173 int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
 174                                      struct drm_fb_helper_surface_size *sizes)
 175 {
 176         struct drm_client_dev *client = &fb_helper->client;
 177         struct drm_device *dev = fb_helper->dev;
 178         struct drm_client_buffer *buffer;
 179         struct fb_info *info;
 180         size_t screen_size;
 181         void *screen_buffer;
 182         u32 format;
 183         int ret;
 184
 185         drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
 186                     sizes->surface_width, sizes->surface_height,
 187                     sizes->surface_bpp);
 188
 189         format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp,
 190                                              sizes->surface_depth);
 191         buffer = drm_client_framebuffer_create(client, sizes->surface_width,
 192                                                sizes->surface_height, format);
 193         if (IS_ERR(buffer))
 194                 return PTR_ERR(buffer);
 195
 196         fb_helper->funcs = &drm_fbdev_ttm_helper_funcs;
 197         fb_helper->buffer = buffer;
 198         fb_helper->fb = buffer->fb;
 199
 200         screen_size = buffer->gem->size;
 201         screen_buffer = vzalloc(screen_size);
 202         if (!screen_buffer) {
 203                 ret = -ENOMEM;
 204                 goto err_drm_client_framebuffer_delete;
 205         }
 206
 207         info = drm_fb_helper_alloc_info(fb_helper);
 208         if (IS_ERR(info)) {
 209                 ret = PTR_ERR(info);
 210                 goto err_vfree;
 211         }
 212
 213         drm_fb_helper_fill_info(info, fb_helper, sizes);
 214
 215         info->fbops = &drm_fbdev_ttm_fb_ops;
 216
 217         /* screen */
 218         info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
 219         info->screen_buffer = screen_buffer;
 220         info->fix.smem_len = screen_size;
 221
 222         /* deferred I/O */
 223         fb_helper->fbdefio.delay = HZ / 20;
 224         fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
 225
 226         info->fbdefio = &fb_helper->fbdefio;
 227         ret = fb_deferred_io_init(info);
 228         if (ret)
 229                 goto err_drm_fb_helper_release_info;
 230
 231         return 0;
 232
 233 err_drm_fb_helper_release_info:
 234         drm_fb_helper_release_info(fb_helper);
 235 err_vfree:
 236         vfree(screen_buffer);
 237 err_drm_client_framebuffer_delete:
 238         fb_helper->fb = NULL;
 239         fb_helper->buffer = NULL;
 240         drm_client_framebuffer_delete(buffer);
 241         return ret;
 242 }
 243 EXPORT_SYMBOL(drm_fbdev_ttm_driver_fbdev_probe);