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