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