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 #ifdef __linux__ 16 /* @user: 1=userspace, 0=fbcon */ 17 static int drm_fbdev_generic_fb_open(struct fb_info *info, int user) 18 { 19 struct drm_fb_helper *fb_helper = info->par; 20 21 /* No need to take a ref for fbcon because it unbinds on unregister */ 22 if (user && !try_module_get(fb_helper->dev->driver->fops->owner)) 23 return -ENODEV; 24 25 return 0; 26 } 27 28 static int drm_fbdev_generic_fb_release(struct fb_info *info, int user) 29 { 30 struct drm_fb_helper *fb_helper = info->par; 31 32 if (user) 33 module_put(fb_helper->dev->driver->fops->owner); 34 35 return 0; 36 } 37 38 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_generic, 39 drm_fb_helper_damage_range, 40 drm_fb_helper_damage_area); 41 42 static void drm_fbdev_generic_fb_destroy(struct fb_info *info) 43 { 44 struct drm_fb_helper *fb_helper = info->par; 45 void *shadow = info->screen_buffer; 46 47 if (!fb_helper->dev) 48 return; 49 50 #ifdef notyet 51 fb_deferred_io_cleanup(info); 52 #endif 53 drm_fb_helper_fini(fb_helper); 54 vfree(shadow); 55 drm_client_framebuffer_delete(fb_helper->buffer); 56 57 drm_client_release(&fb_helper->client); 58 drm_fb_helper_unprepare(fb_helper); 59 kfree(fb_helper); 60 } 61 62 #endif /* __linux__ */ 63 64 static const struct fb_ops drm_fbdev_generic_fb_ops = { 65 #ifdef notyet 66 .owner = THIS_MODULE, 67 .fb_open = drm_fbdev_generic_fb_open, 68 .fb_release = drm_fbdev_generic_fb_release, 69 FB_DEFAULT_DEFERRED_OPS(drm_fbdev_generic), 70 DRM_FB_HELPER_DEFAULT_OPS, 71 .fb_destroy = drm_fbdev_generic_fb_destroy, 72 #else 73 DRM_FB_HELPER_DEFAULT_OPS, 74 #endif 75 }; 76 77 /* 78 * This function uses the client API to create a framebuffer backed by a dumb buffer. 79 */ 80 static int drm_fbdev_generic_helper_fb_probe(struct drm_fb_helper *fb_helper, 81 struct drm_fb_helper_surface_size *sizes) 82 { 83 struct drm_client_dev *client = &fb_helper->client; 84 struct drm_device *dev = fb_helper->dev; 85 struct drm_client_buffer *buffer; 86 struct fb_info *info; 87 size_t screen_size; 88 void *screen_buffer; 89 u32 format; 90 int ret; 91 92 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n", 93 sizes->surface_width, sizes->surface_height, 94 sizes->surface_bpp); 95 96 format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth); 97 buffer = drm_client_framebuffer_create(client, sizes->surface_width, 98 sizes->surface_height, format); 99 if (IS_ERR(buffer)) 100 return PTR_ERR(buffer); 101 102 fb_helper->buffer = buffer; 103 fb_helper->fb = buffer->fb; 104 105 screen_size = buffer->gem->size; 106 screen_buffer = vzalloc(screen_size); 107 if (!screen_buffer) { 108 ret = -ENOMEM; 109 goto err_drm_client_framebuffer_delete; 110 } 111 112 info = drm_fb_helper_alloc_info(fb_helper); 113 if (IS_ERR(info)) { 114 ret = PTR_ERR(info); 115 goto err_vfree; 116 } 117 118 drm_fb_helper_fill_info(info, fb_helper, sizes); 119 120 info->fbops = &drm_fbdev_generic_fb_ops; 121 122 /* screen */ 123 info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST; 124 info->screen_buffer = screen_buffer; 125 info->fix.smem_start = page_to_phys(vmalloc_to_page(info->screen_buffer)); 126 info->fix.smem_len = screen_size; 127 128 #ifdef notyet 129 /* deferred I/O */ 130 fb_helper->fbdefio.delay = HZ / 20; 131 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; 132 133 info->fbdefio = &fb_helper->fbdefio; 134 ret = fb_deferred_io_init(info); 135 if (ret) 136 goto err_drm_fb_helper_release_info; 137 #endif 138 139 return 0; 140 141 #ifdef notyet 142 err_drm_fb_helper_release_info: 143 drm_fb_helper_release_info(fb_helper); 144 #endif 145 err_vfree: 146 vfree(screen_buffer); 147 err_drm_client_framebuffer_delete: 148 fb_helper->fb = NULL; 149 fb_helper->buffer = NULL; 150 drm_client_framebuffer_delete(buffer); 151 return ret; 152 } 153 154 static void drm_fbdev_generic_damage_blit_real(struct drm_fb_helper *fb_helper, 155 struct drm_clip_rect *clip, 156 struct iosys_map *dst) 157 { 158 struct drm_framebuffer *fb = fb_helper->fb; 159 size_t offset = clip->y1 * fb->pitches[0]; 160 size_t len = clip->x2 - clip->x1; 161 unsigned int y; 162 void *src; 163 164 switch (drm_format_info_bpp(fb->format, 0)) { 165 case 1: 166 offset += clip->x1 / 8; 167 len = DIV_ROUND_UP(len + clip->x1 % 8, 8); 168 break; 169 case 2: 170 offset += clip->x1 / 4; 171 len = DIV_ROUND_UP(len + clip->x1 % 4, 4); 172 break; 173 case 4: 174 offset += clip->x1 / 2; 175 len = DIV_ROUND_UP(len + clip->x1 % 2, 2); 176 break; 177 default: 178 offset += clip->x1 * fb->format->cpp[0]; 179 len *= fb->format->cpp[0]; 180 break; 181 } 182 183 src = fb_helper->info->screen_buffer + offset; 184 iosys_map_incr(dst, offset); /* go to first pixel within clip rect */ 185 186 for (y = clip->y1; y < clip->y2; y++) { 187 iosys_map_memcpy_to(dst, 0, src, len); 188 iosys_map_incr(dst, fb->pitches[0]); 189 src += fb->pitches[0]; 190 } 191 } 192 193 static int drm_fbdev_generic_damage_blit(struct drm_fb_helper *fb_helper, 194 struct drm_clip_rect *clip) 195 { 196 struct drm_client_buffer *buffer = fb_helper->buffer; 197 struct iosys_map map, dst; 198 int ret; 199 200 /* 201 * We have to pin the client buffer to its current location while 202 * flushing the shadow buffer. In the general case, concurrent 203 * modesetting operations could try to move the buffer and would 204 * fail. The modeset has to be serialized by acquiring the reservation 205 * object of the underlying BO here. 206 * 207 * For fbdev emulation, we only have to protect against fbdev modeset 208 * operations. Nothing else will involve the client buffer's BO. So it 209 * is sufficient to acquire struct drm_fb_helper.lock here. 210 */ 211 mutex_lock(&fb_helper->lock); 212 213 ret = drm_client_buffer_vmap(buffer, &map); 214 if (ret) 215 goto out; 216 217 dst = map; 218 drm_fbdev_generic_damage_blit_real(fb_helper, clip, &dst); 219 220 drm_client_buffer_vunmap(buffer); 221 222 out: 223 mutex_unlock(&fb_helper->lock); 224 225 return ret; 226 } 227 228 static int drm_fbdev_generic_helper_fb_dirty(struct drm_fb_helper *helper, 229 struct drm_clip_rect *clip) 230 { 231 struct drm_device *dev = helper->dev; 232 int ret; 233 234 /* Call damage handlers only if necessary */ 235 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2)) 236 return 0; 237 238 ret = drm_fbdev_generic_damage_blit(helper, clip); 239 if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret)) 240 return ret; 241 242 if (helper->fb->funcs->dirty) { 243 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1); 244 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret)) 245 return ret; 246 } 247 248 return 0; 249 } 250 251 static const struct drm_fb_helper_funcs drm_fbdev_generic_helper_funcs = { 252 .fb_probe = drm_fbdev_generic_helper_fb_probe, 253 .fb_dirty = drm_fbdev_generic_helper_fb_dirty, 254 }; 255 256 static void drm_fbdev_generic_client_unregister(struct drm_client_dev *client) 257 { 258 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 259 260 if (fb_helper->info) { 261 drm_fb_helper_unregister_info(fb_helper); 262 } else { 263 drm_client_release(&fb_helper->client); 264 drm_fb_helper_unprepare(fb_helper); 265 kfree(fb_helper); 266 } 267 } 268 269 static int drm_fbdev_generic_client_restore(struct drm_client_dev *client) 270 { 271 drm_fb_helper_lastclose(client->dev); 272 273 return 0; 274 } 275 276 static int drm_fbdev_generic_client_hotplug(struct drm_client_dev *client) 277 { 278 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 279 struct drm_device *dev = client->dev; 280 int ret; 281 282 if (dev->fb_helper) 283 return drm_fb_helper_hotplug_event(dev->fb_helper); 284 285 ret = drm_fb_helper_init(dev, fb_helper); 286 if (ret) 287 goto err_drm_err; 288 289 if (!drm_drv_uses_atomic_modeset(dev)) 290 drm_helper_disable_unused_functions(dev); 291 292 ret = drm_fb_helper_initial_config(fb_helper); 293 if (ret) 294 goto err_drm_fb_helper_fini; 295 296 return 0; 297 298 err_drm_fb_helper_fini: 299 drm_fb_helper_fini(fb_helper); 300 err_drm_err: 301 drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret); 302 return ret; 303 } 304 305 static const struct drm_client_funcs drm_fbdev_generic_client_funcs = { 306 .owner = THIS_MODULE, 307 .unregister = drm_fbdev_generic_client_unregister, 308 .restore = drm_fbdev_generic_client_restore, 309 .hotplug = drm_fbdev_generic_client_hotplug, 310 }; 311 312 /** 313 * drm_fbdev_generic_setup() - Setup generic fbdev emulation 314 * @dev: DRM device 315 * @preferred_bpp: Preferred bits per pixel for the device. 316 * 317 * This function sets up generic fbdev emulation for drivers that supports 318 * dumb buffers with a virtual address and that can be mmap'ed. 319 * drm_fbdev_generic_setup() shall be called after the DRM driver registered 320 * the new DRM device with drm_dev_register(). 321 * 322 * Restore, hotplug events and teardown are all taken care of. Drivers that do 323 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves. 324 * Simple drivers might use drm_mode_config_helper_suspend(). 325 * 326 * In order to provide fixed mmap-able memory ranges, generic fbdev emulation 327 * uses a shadow buffer in system memory. The implementation blits the shadow 328 * fbdev buffer onto the real buffer in regular intervals. 329 * 330 * This function is safe to call even when there are no connectors present. 331 * Setup will be retried on the next hotplug event. 332 * 333 * The fbdev is destroyed by drm_dev_unregister(). 334 */ 335 void drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) 336 { 337 struct drm_fb_helper *fb_helper; 338 int ret; 339 340 drm_WARN(dev, !dev->registered, "Device has not been registered.\n"); 341 drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n"); 342 343 fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL); 344 if (!fb_helper) 345 return; 346 drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_generic_helper_funcs); 347 348 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_generic_client_funcs); 349 if (ret) { 350 drm_err(dev, "Failed to register client: %d\n", ret); 351 goto err_drm_client_init; 352 } 353 354 drm_client_register(&fb_helper->client); 355 356 return; 357 358 err_drm_client_init: 359 drm_fb_helper_unprepare(fb_helper); 360 kfree(fb_helper); 361 return; 362 } 363 EXPORT_SYMBOL(drm_fbdev_generic_setup); 364