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_generic.h> 14 15 /* @user: 1=userspace, 0=fbcon */ 16 static int drm_fbdev_generic_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_generic_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_SYS_OPS(drm_fbdev_generic, 38 drm_fb_helper_damage_range, 39 drm_fb_helper_damage_area); 40 41 static void drm_fbdev_generic_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_generic_fb_ops = { 60 .owner = THIS_MODULE, 61 .fb_open = drm_fbdev_generic_fb_open, 62 .fb_release = drm_fbdev_generic_fb_release, 63 FB_DEFAULT_DEFERRED_OPS(drm_fbdev_generic), 64 DRM_FB_HELPER_DEFAULT_OPS, 65 .fb_destroy = drm_fbdev_generic_fb_destroy, 66 }; 67 68 /* 69 * This function uses the client API to create a framebuffer backed by a dumb buffer. 70 */ 71 static int drm_fbdev_generic_helper_fb_probe(struct drm_fb_helper *fb_helper, 72 struct drm_fb_helper_surface_size *sizes) 73 { 74 struct drm_client_dev *client = &fb_helper->client; 75 struct drm_device *dev = fb_helper->dev; 76 struct drm_client_buffer *buffer; 77 struct fb_info *info; 78 size_t screen_size; 79 void *screen_buffer; 80 u32 format; 81 int ret; 82 83 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n", 84 sizes->surface_width, sizes->surface_height, 85 sizes->surface_bpp); 86 87 format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth); 88 buffer = drm_client_framebuffer_create(client, sizes->surface_width, 89 sizes->surface_height, format); 90 if (IS_ERR(buffer)) 91 return PTR_ERR(buffer); 92 93 fb_helper->buffer = buffer; 94 fb_helper->fb = buffer->fb; 95 96 screen_size = buffer->gem->size; 97 screen_buffer = vzalloc(screen_size); 98 if (!screen_buffer) { 99 ret = -ENOMEM; 100 goto err_drm_client_framebuffer_delete; 101 } 102 103 info = drm_fb_helper_alloc_info(fb_helper); 104 if (IS_ERR(info)) { 105 ret = PTR_ERR(info); 106 goto err_vfree; 107 } 108 109 drm_fb_helper_fill_info(info, fb_helper, sizes); 110 111 info->fbops = &drm_fbdev_generic_fb_ops; 112 info->flags = FBINFO_DEFAULT; 113 114 /* screen */ 115 info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST; 116 info->screen_buffer = screen_buffer; 117 info->fix.smem_start = page_to_phys(vmalloc_to_page(info->screen_buffer)); 118 info->fix.smem_len = screen_size; 119 120 /* deferred I/O */ 121 fb_helper->fbdefio.delay = HZ / 20; 122 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; 123 124 info->fbdefio = &fb_helper->fbdefio; 125 ret = fb_deferred_io_init(info); 126 if (ret) 127 goto err_drm_fb_helper_release_info; 128 129 return 0; 130 131 err_drm_fb_helper_release_info: 132 drm_fb_helper_release_info(fb_helper); 133 err_vfree: 134 vfree(screen_buffer); 135 err_drm_client_framebuffer_delete: 136 fb_helper->fb = NULL; 137 fb_helper->buffer = NULL; 138 drm_client_framebuffer_delete(buffer); 139 return ret; 140 } 141 142 static void drm_fbdev_generic_damage_blit_real(struct drm_fb_helper *fb_helper, 143 struct drm_clip_rect *clip, 144 struct iosys_map *dst) 145 { 146 struct drm_framebuffer *fb = fb_helper->fb; 147 size_t offset = clip->y1 * fb->pitches[0]; 148 size_t len = clip->x2 - clip->x1; 149 unsigned int y; 150 void *src; 151 152 switch (drm_format_info_bpp(fb->format, 0)) { 153 case 1: 154 offset += clip->x1 / 8; 155 len = DIV_ROUND_UP(len + clip->x1 % 8, 8); 156 break; 157 case 2: 158 offset += clip->x1 / 4; 159 len = DIV_ROUND_UP(len + clip->x1 % 4, 4); 160 break; 161 case 4: 162 offset += clip->x1 / 2; 163 len = DIV_ROUND_UP(len + clip->x1 % 2, 2); 164 break; 165 default: 166 offset += clip->x1 * fb->format->cpp[0]; 167 len *= fb->format->cpp[0]; 168 break; 169 } 170 171 src = fb_helper->info->screen_buffer + offset; 172 iosys_map_incr(dst, offset); /* go to first pixel within clip rect */ 173 174 for (y = clip->y1; y < clip->y2; y++) { 175 iosys_map_memcpy_to(dst, 0, src, len); 176 iosys_map_incr(dst, fb->pitches[0]); 177 src += fb->pitches[0]; 178 } 179 } 180 181 static int drm_fbdev_generic_damage_blit(struct drm_fb_helper *fb_helper, 182 struct drm_clip_rect *clip) 183 { 184 struct drm_client_buffer *buffer = fb_helper->buffer; 185 struct iosys_map map, dst; 186 int ret; 187 188 /* 189 * We have to pin the client buffer to its current location while 190 * flushing the shadow buffer. In the general case, concurrent 191 * modesetting operations could try to move the buffer and would 192 * fail. The modeset has to be serialized by acquiring the reservation 193 * object of the underlying BO here. 194 * 195 * For fbdev emulation, we only have to protect against fbdev modeset 196 * operations. Nothing else will involve the client buffer's BO. So it 197 * is sufficient to acquire struct drm_fb_helper.lock here. 198 */ 199 mutex_lock(&fb_helper->lock); 200 201 ret = drm_client_buffer_vmap(buffer, &map); 202 if (ret) 203 goto out; 204 205 dst = map; 206 drm_fbdev_generic_damage_blit_real(fb_helper, clip, &dst); 207 208 drm_client_buffer_vunmap(buffer); 209 210 out: 211 mutex_unlock(&fb_helper->lock); 212 213 return ret; 214 } 215 216 static int drm_fbdev_generic_helper_fb_dirty(struct drm_fb_helper *helper, 217 struct drm_clip_rect *clip) 218 { 219 struct drm_device *dev = helper->dev; 220 int ret; 221 222 /* Call damage handlers only if necessary */ 223 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2)) 224 return 0; 225 226 ret = drm_fbdev_generic_damage_blit(helper, clip); 227 if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret)) 228 return ret; 229 230 if (helper->fb->funcs->dirty) { 231 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1); 232 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret)) 233 return ret; 234 } 235 236 return 0; 237 } 238 239 static const struct drm_fb_helper_funcs drm_fbdev_generic_helper_funcs = { 240 .fb_probe = drm_fbdev_generic_helper_fb_probe, 241 .fb_dirty = drm_fbdev_generic_helper_fb_dirty, 242 }; 243 244 static void drm_fbdev_generic_client_unregister(struct drm_client_dev *client) 245 { 246 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 247 248 if (fb_helper->info) { 249 drm_fb_helper_unregister_info(fb_helper); 250 } else { 251 drm_client_release(&fb_helper->client); 252 drm_fb_helper_unprepare(fb_helper); 253 kfree(fb_helper); 254 } 255 } 256 257 static int drm_fbdev_generic_client_restore(struct drm_client_dev *client) 258 { 259 drm_fb_helper_lastclose(client->dev); 260 261 return 0; 262 } 263 264 static int drm_fbdev_generic_client_hotplug(struct drm_client_dev *client) 265 { 266 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 267 struct drm_device *dev = client->dev; 268 int ret; 269 270 if (dev->fb_helper) 271 return drm_fb_helper_hotplug_event(dev->fb_helper); 272 273 ret = drm_fb_helper_init(dev, fb_helper); 274 if (ret) 275 goto err_drm_err; 276 277 if (!drm_drv_uses_atomic_modeset(dev)) 278 drm_helper_disable_unused_functions(dev); 279 280 ret = drm_fb_helper_initial_config(fb_helper); 281 if (ret) 282 goto err_drm_fb_helper_fini; 283 284 return 0; 285 286 err_drm_fb_helper_fini: 287 drm_fb_helper_fini(fb_helper); 288 err_drm_err: 289 drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret); 290 return ret; 291 } 292 293 static const struct drm_client_funcs drm_fbdev_generic_client_funcs = { 294 .owner = THIS_MODULE, 295 .unregister = drm_fbdev_generic_client_unregister, 296 .restore = drm_fbdev_generic_client_restore, 297 .hotplug = drm_fbdev_generic_client_hotplug, 298 }; 299 300 /** 301 * drm_fbdev_generic_setup() - Setup generic fbdev emulation 302 * @dev: DRM device 303 * @preferred_bpp: Preferred bits per pixel for the device. 304 * 305 * This function sets up generic fbdev emulation for drivers that supports 306 * dumb buffers with a virtual address and that can be mmap'ed. 307 * drm_fbdev_generic_setup() shall be called after the DRM driver registered 308 * the new DRM device with drm_dev_register(). 309 * 310 * Restore, hotplug events and teardown are all taken care of. Drivers that do 311 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves. 312 * Simple drivers might use drm_mode_config_helper_suspend(). 313 * 314 * In order to provide fixed mmap-able memory ranges, generic fbdev emulation 315 * uses a shadow buffer in system memory. The implementation blits the shadow 316 * fbdev buffer onto the real buffer in regular intervals. 317 * 318 * This function is safe to call even when there are no connectors present. 319 * Setup will be retried on the next hotplug event. 320 * 321 * The fbdev is destroyed by drm_dev_unregister(). 322 */ 323 void drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) 324 { 325 struct drm_fb_helper *fb_helper; 326 int ret; 327 328 drm_WARN(dev, !dev->registered, "Device has not been registered.\n"); 329 drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n"); 330 331 fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL); 332 if (!fb_helper) 333 return; 334 drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_generic_helper_funcs); 335 336 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_generic_client_funcs); 337 if (ret) { 338 drm_err(dev, "Failed to register client: %d\n", ret); 339 goto err_drm_client_init; 340 } 341 342 drm_client_register(&fb_helper->client); 343 344 return; 345 346 err_drm_client_init: 347 drm_fb_helper_unprepare(fb_helper); 348 kfree(fb_helper); 349 return; 350 } 351 EXPORT_SYMBOL(drm_fbdev_generic_setup); 352