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_framebuffer_helper.h> 10 #include <drm/drm_gem_shmem_helper.h> 11 12 #include <drm/drm_fbdev_shmem.h> 13 14 /* 15 * struct fb_ops 16 */ 17 18 static int drm_fbdev_shmem_fb_open(struct fb_info *info, int user) 19 { 20 struct drm_fb_helper *fb_helper = info->par; 21 22 /* No need to take a ref for fbcon because it unbinds on unregister */ 23 if (user && !try_module_get(fb_helper->dev->driver->fops->owner)) 24 return -ENODEV; 25 26 return 0; 27 } 28 29 static int drm_fbdev_shmem_fb_release(struct fb_info *info, int user) 30 { 31 struct drm_fb_helper *fb_helper = info->par; 32 33 if (user) 34 module_put(fb_helper->dev->driver->fops->owner); 35 36 return 0; 37 } 38 39 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_shmem, 40 drm_fb_helper_damage_range, 41 drm_fb_helper_damage_area); 42 43 static int drm_fbdev_shmem_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) 44 { 45 struct drm_fb_helper *fb_helper = info->par; 46 struct drm_framebuffer *fb = fb_helper->fb; 47 struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, 0); 48 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); 49 50 if (shmem->map_wc) 51 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); 52 53 return fb_deferred_io_mmap(info, vma); 54 } 55 56 static void drm_fbdev_shmem_fb_destroy(struct fb_info *info) 57 { 58 struct drm_fb_helper *fb_helper = info->par; 59 60 if (!fb_helper->dev) 61 return; 62 63 drm_fb_helper_fini(fb_helper); 64 65 drm_client_buffer_vunmap(fb_helper->buffer); 66 drm_client_framebuffer_delete(fb_helper->buffer); 67 drm_client_release(&fb_helper->client); 68 drm_fb_helper_unprepare(fb_helper); 69 kfree(fb_helper); 70 } 71 72 static const struct fb_ops drm_fbdev_shmem_fb_ops = { 73 .owner = THIS_MODULE, 74 .fb_open = drm_fbdev_shmem_fb_open, 75 .fb_release = drm_fbdev_shmem_fb_release, 76 __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_shmem), 77 DRM_FB_HELPER_DEFAULT_OPS, 78 __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_shmem), 79 .fb_mmap = drm_fbdev_shmem_fb_mmap, 80 .fb_destroy = drm_fbdev_shmem_fb_destroy, 81 }; 82 83 static struct page *drm_fbdev_shmem_get_page(struct fb_info *info, unsigned long offset) 84 { 85 struct drm_fb_helper *fb_helper = info->par; 86 struct drm_framebuffer *fb = fb_helper->fb; 87 struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, 0); 88 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); 89 unsigned int i = offset >> PAGE_SHIFT; 90 struct page *page; 91 92 if (fb_WARN_ON_ONCE(info, offset > obj->size)) 93 return NULL; 94 95 page = shmem->pages[i]; // protected by active vmap 96 if (page) 97 get_page(page); 98 fb_WARN_ON_ONCE(info, !page); 99 100 return page; 101 } 102 103 /* 104 * struct drm_fb_helper 105 */ 106 107 static int drm_fbdev_shmem_helper_fb_probe(struct drm_fb_helper *fb_helper, 108 struct drm_fb_helper_surface_size *sizes) 109 { 110 struct drm_client_dev *client = &fb_helper->client; 111 struct drm_device *dev = fb_helper->dev; 112 struct drm_client_buffer *buffer; 113 struct drm_gem_shmem_object *shmem; 114 struct drm_framebuffer *fb; 115 struct fb_info *info; 116 u32 format; 117 struct iosys_map map; 118 int ret; 119 120 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n", 121 sizes->surface_width, sizes->surface_height, 122 sizes->surface_bpp); 123 124 format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp, sizes->surface_depth); 125 buffer = drm_client_framebuffer_create(client, sizes->surface_width, 126 sizes->surface_height, format); 127 if (IS_ERR(buffer)) 128 return PTR_ERR(buffer); 129 shmem = to_drm_gem_shmem_obj(buffer->gem); 130 131 fb = buffer->fb; 132 133 ret = drm_client_buffer_vmap(buffer, &map); 134 if (ret) { 135 goto err_drm_client_buffer_delete; 136 } else if (drm_WARN_ON(dev, map.is_iomem)) { 137 ret = -ENODEV; /* I/O memory not supported; use generic emulation */ 138 goto err_drm_client_buffer_delete; 139 } 140 141 fb_helper->buffer = buffer; 142 fb_helper->fb = fb; 143 144 info = drm_fb_helper_alloc_info(fb_helper); 145 if (IS_ERR(info)) { 146 ret = PTR_ERR(info); 147 goto err_drm_client_buffer_vunmap; 148 } 149 150 drm_fb_helper_fill_info(info, fb_helper, sizes); 151 152 info->fbops = &drm_fbdev_shmem_fb_ops; 153 154 /* screen */ 155 info->flags |= FBINFO_VIRTFB; /* system memory */ 156 if (!shmem->map_wc) 157 info->flags |= FBINFO_READS_FAST; /* signal caching */ 158 info->screen_size = sizes->surface_height * fb->pitches[0]; 159 info->screen_buffer = map.vaddr; 160 info->fix.smem_len = info->screen_size; 161 162 /* deferred I/O */ 163 fb_helper->fbdefio.delay = HZ / 20; 164 fb_helper->fbdefio.get_page = drm_fbdev_shmem_get_page; 165 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; 166 167 info->fbdefio = &fb_helper->fbdefio; 168 ret = fb_deferred_io_init(info); 169 if (ret) 170 goto err_drm_fb_helper_release_info; 171 172 return 0; 173 174 err_drm_fb_helper_release_info: 175 drm_fb_helper_release_info(fb_helper); 176 err_drm_client_buffer_vunmap: 177 fb_helper->fb = NULL; 178 fb_helper->buffer = NULL; 179 drm_client_buffer_vunmap(buffer); 180 err_drm_client_buffer_delete: 181 drm_client_framebuffer_delete(buffer); 182 return ret; 183 } 184 185 static int drm_fbdev_shmem_helper_fb_dirty(struct drm_fb_helper *helper, 186 struct drm_clip_rect *clip) 187 { 188 struct drm_device *dev = helper->dev; 189 int ret; 190 191 /* Call damage handlers only if necessary */ 192 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2)) 193 return 0; 194 195 if (helper->fb->funcs->dirty) { 196 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1); 197 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret)) 198 return ret; 199 } 200 201 return 0; 202 } 203 204 static const struct drm_fb_helper_funcs drm_fbdev_shmem_helper_funcs = { 205 .fb_probe = drm_fbdev_shmem_helper_fb_probe, 206 .fb_dirty = drm_fbdev_shmem_helper_fb_dirty, 207 }; 208 209 /* 210 * struct drm_client_funcs 211 */ 212 213 static void drm_fbdev_shmem_client_unregister(struct drm_client_dev *client) 214 { 215 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 216 217 if (fb_helper->info) { 218 drm_fb_helper_unregister_info(fb_helper); 219 } else { 220 drm_client_release(&fb_helper->client); 221 drm_fb_helper_unprepare(fb_helper); 222 kfree(fb_helper); 223 } 224 } 225 226 static int drm_fbdev_shmem_client_restore(struct drm_client_dev *client) 227 { 228 drm_fb_helper_lastclose(client->dev); 229 230 return 0; 231 } 232 233 static int drm_fbdev_shmem_client_hotplug(struct drm_client_dev *client) 234 { 235 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 236 struct drm_device *dev = client->dev; 237 int ret; 238 239 if (dev->fb_helper) 240 return drm_fb_helper_hotplug_event(dev->fb_helper); 241 242 ret = drm_fb_helper_init(dev, fb_helper); 243 if (ret) 244 goto err_drm_err; 245 246 if (!drm_drv_uses_atomic_modeset(dev)) 247 drm_helper_disable_unused_functions(dev); 248 249 ret = drm_fb_helper_initial_config(fb_helper); 250 if (ret) 251 goto err_drm_fb_helper_fini; 252 253 return 0; 254 255 err_drm_fb_helper_fini: 256 drm_fb_helper_fini(fb_helper); 257 err_drm_err: 258 drm_err(dev, "fbdev-shmem: Failed to setup emulation (ret=%d)\n", ret); 259 return ret; 260 } 261 262 static const struct drm_client_funcs drm_fbdev_shmem_client_funcs = { 263 .owner = THIS_MODULE, 264 .unregister = drm_fbdev_shmem_client_unregister, 265 .restore = drm_fbdev_shmem_client_restore, 266 .hotplug = drm_fbdev_shmem_client_hotplug, 267 }; 268 269 /** 270 * drm_fbdev_shmem_setup() - Setup fbdev emulation for GEM SHMEM helpers 271 * @dev: DRM device 272 * @preferred_bpp: Preferred bits per pixel for the device. 273 * 32 is used if this is zero. 274 * 275 * This function sets up fbdev emulation for GEM DMA drivers that support 276 * dumb buffers with a virtual address and that can be mmap'ed. 277 * drm_fbdev_shmem_setup() shall be called after the DRM driver registered 278 * the new DRM device with drm_dev_register(). 279 * 280 * Restore, hotplug events and teardown are all taken care of. Drivers that do 281 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves. 282 * Simple drivers might use drm_mode_config_helper_suspend(). 283 * 284 * This function is safe to call even when there are no connectors present. 285 * Setup will be retried on the next hotplug event. 286 * 287 * The fbdev is destroyed by drm_dev_unregister(). 288 */ 289 void drm_fbdev_shmem_setup(struct drm_device *dev, unsigned int preferred_bpp) 290 { 291 struct drm_fb_helper *fb_helper; 292 int ret; 293 294 drm_WARN(dev, !dev->registered, "Device has not been registered.\n"); 295 drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n"); 296 297 fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL); 298 if (!fb_helper) 299 return; 300 drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_shmem_helper_funcs); 301 302 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_shmem_client_funcs); 303 if (ret) { 304 drm_err(dev, "Failed to register client: %d\n", ret); 305 goto err_drm_client_init; 306 } 307 308 drm_client_register(&fb_helper->client); 309 310 return; 311 312 err_drm_client_init: 313 drm_fb_helper_unprepare(fb_helper); 314 kfree(fb_helper); 315 } 316 EXPORT_SYMBOL(drm_fbdev_shmem_setup); 317