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_len = screen_size; 126 127 #ifdef notyet 128 /* deferred I/O */ 129 fb_helper->fbdefio.delay = HZ / 20; 130 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; 131 132 info->fbdefio = &fb_helper->fbdefio; 133 ret = fb_deferred_io_init(info); 134 if (ret) 135 goto err_drm_fb_helper_release_info; 136 #endif 137 138 return 0; 139 140 #ifdef notyet 141 err_drm_fb_helper_release_info: 142 drm_fb_helper_release_info(fb_helper); 143 #endif 144 err_vfree: 145 vfree(screen_buffer); 146 err_drm_client_framebuffer_delete: 147 fb_helper->fb = NULL; 148 fb_helper->buffer = NULL; 149 drm_client_framebuffer_delete(buffer); 150 return ret; 151 } 152 153 static void drm_fbdev_generic_damage_blit_real(struct drm_fb_helper *fb_helper, 154 struct drm_clip_rect *clip, 155 struct iosys_map *dst) 156 { 157 struct drm_framebuffer *fb = fb_helper->fb; 158 size_t offset = clip->y1 * fb->pitches[0]; 159 size_t len = clip->x2 - clip->x1; 160 unsigned int y; 161 void *src; 162 163 switch (drm_format_info_bpp(fb->format, 0)) { 164 case 1: 165 offset += clip->x1 / 8; 166 len = DIV_ROUND_UP(len + clip->x1 % 8, 8); 167 break; 168 case 2: 169 offset += clip->x1 / 4; 170 len = DIV_ROUND_UP(len + clip->x1 % 4, 4); 171 break; 172 case 4: 173 offset += clip->x1 / 2; 174 len = DIV_ROUND_UP(len + clip->x1 % 2, 2); 175 break; 176 default: 177 offset += clip->x1 * fb->format->cpp[0]; 178 len *= fb->format->cpp[0]; 179 break; 180 } 181 182 src = fb_helper->info->screen_buffer + offset; 183 iosys_map_incr(dst, offset); /* go to first pixel within clip rect */ 184 185 for (y = clip->y1; y < clip->y2; y++) { 186 iosys_map_memcpy_to(dst, 0, src, len); 187 iosys_map_incr(dst, fb->pitches[0]); 188 src += fb->pitches[0]; 189 } 190 } 191 192 static int drm_fbdev_generic_damage_blit(struct drm_fb_helper *fb_helper, 193 struct drm_clip_rect *clip) 194 { 195 struct drm_client_buffer *buffer = fb_helper->buffer; 196 struct iosys_map map, dst; 197 int ret; 198 199 /* 200 * We have to pin the client buffer to its current location while 201 * flushing the shadow buffer. In the general case, concurrent 202 * modesetting operations could try to move the buffer and would 203 * fail. The modeset has to be serialized by acquiring the reservation 204 * object of the underlying BO here. 205 * 206 * For fbdev emulation, we only have to protect against fbdev modeset 207 * operations. Nothing else will involve the client buffer's BO. So it 208 * is sufficient to acquire struct drm_fb_helper.lock here. 209 */ 210 mutex_lock(&fb_helper->lock); 211 212 ret = drm_client_buffer_vmap(buffer, &map); 213 if (ret) 214 goto out; 215 216 dst = map; 217 drm_fbdev_generic_damage_blit_real(fb_helper, clip, &dst); 218 219 drm_client_buffer_vunmap(buffer); 220 221 out: 222 mutex_unlock(&fb_helper->lock); 223 224 return ret; 225 } 226 227 static int drm_fbdev_generic_helper_fb_dirty(struct drm_fb_helper *helper, 228 struct drm_clip_rect *clip) 229 { 230 struct drm_device *dev = helper->dev; 231 int ret; 232 233 /* Call damage handlers only if necessary */ 234 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2)) 235 return 0; 236 237 ret = drm_fbdev_generic_damage_blit(helper, clip); 238 if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret)) 239 return ret; 240 241 if (helper->fb->funcs->dirty) { 242 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1); 243 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret)) 244 return ret; 245 } 246 247 return 0; 248 } 249 250 static const struct drm_fb_helper_funcs drm_fbdev_generic_helper_funcs = { 251 .fb_probe = drm_fbdev_generic_helper_fb_probe, 252 .fb_dirty = drm_fbdev_generic_helper_fb_dirty, 253 }; 254 255 static void drm_fbdev_generic_client_unregister(struct drm_client_dev *client) 256 { 257 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 258 259 if (fb_helper->info) { 260 drm_fb_helper_unregister_info(fb_helper); 261 } else { 262 drm_client_release(&fb_helper->client); 263 drm_fb_helper_unprepare(fb_helper); 264 kfree(fb_helper); 265 } 266 } 267 268 static int drm_fbdev_generic_client_restore(struct drm_client_dev *client) 269 { 270 drm_fb_helper_lastclose(client->dev); 271 272 return 0; 273 } 274 275 static int drm_fbdev_generic_client_hotplug(struct drm_client_dev *client) 276 { 277 struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); 278 struct drm_device *dev = client->dev; 279 int ret; 280 281 if (dev->fb_helper) 282 return drm_fb_helper_hotplug_event(dev->fb_helper); 283 284 ret = drm_fb_helper_init(dev, fb_helper); 285 if (ret) 286 goto err_drm_err; 287 288 if (!drm_drv_uses_atomic_modeset(dev)) 289 drm_helper_disable_unused_functions(dev); 290 291 ret = drm_fb_helper_initial_config(fb_helper); 292 if (ret) 293 goto err_drm_fb_helper_fini; 294 295 return 0; 296 297 err_drm_fb_helper_fini: 298 drm_fb_helper_fini(fb_helper); 299 err_drm_err: 300 drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret); 301 return ret; 302 } 303 304 static const struct drm_client_funcs drm_fbdev_generic_client_funcs = { 305 .owner = THIS_MODULE, 306 .unregister = drm_fbdev_generic_client_unregister, 307 .restore = drm_fbdev_generic_client_restore, 308 .hotplug = drm_fbdev_generic_client_hotplug, 309 }; 310 311 /** 312 * drm_fbdev_generic_setup() - Setup generic fbdev emulation 313 * @dev: DRM device 314 * @preferred_bpp: Preferred bits per pixel for the device. 315 * 316 * This function sets up generic fbdev emulation for drivers that supports 317 * dumb buffers with a virtual address and that can be mmap'ed. 318 * drm_fbdev_generic_setup() shall be called after the DRM driver registered 319 * the new DRM device with drm_dev_register(). 320 * 321 * Restore, hotplug events and teardown are all taken care of. Drivers that do 322 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves. 323 * Simple drivers might use drm_mode_config_helper_suspend(). 324 * 325 * In order to provide fixed mmap-able memory ranges, generic fbdev emulation 326 * uses a shadow buffer in system memory. The implementation blits the shadow 327 * fbdev buffer onto the real buffer in regular intervals. 328 * 329 * This function is safe to call even when there are no connectors present. 330 * Setup will be retried on the next hotplug event. 331 * 332 * The fbdev is destroyed by drm_dev_unregister(). 333 */ 334 void drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) 335 { 336 struct drm_fb_helper *fb_helper; 337 int ret; 338 339 drm_WARN(dev, !dev->registered, "Device has not been registered.\n"); 340 drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n"); 341 342 fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL); 343 if (!fb_helper) 344 return; 345 drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_generic_helper_funcs); 346 347 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_generic_client_funcs); 348 if (ret) { 349 drm_err(dev, "Failed to register client: %d\n", ret); 350 goto err_drm_client_init; 351 } 352 353 drm_client_register(&fb_helper->client); 354 355 return; 356 357 err_drm_client_init: 358 drm_fb_helper_unprepare(fb_helper); 359 kfree(fb_helper); 360 return; 361 } 362 EXPORT_SYMBOL(drm_fbdev_generic_setup); 363