351 lines · c
1// SPDX-License-Identifier: MIT2 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_ttm.h>14 15/* @user: 1=userspace, 0=fbcon */16static int drm_fbdev_ttm_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 27static int drm_fbdev_ttm_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 37FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_ttm,38 drm_fb_helper_damage_range,39 drm_fb_helper_damage_area);40 41static void drm_fbdev_ttm_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 59static const struct fb_ops drm_fbdev_ttm_fb_ops = {60 .owner = THIS_MODULE,61 .fb_open = drm_fbdev_ttm_fb_open,62 .fb_release = drm_fbdev_ttm_fb_release,63 FB_DEFAULT_DEFERRED_OPS(drm_fbdev_ttm),64 DRM_FB_HELPER_DEFAULT_OPS,65 .fb_destroy = drm_fbdev_ttm_fb_destroy,66};67 68/*69 * This function uses the client API to create a framebuffer backed by a dumb buffer.70 */71static int drm_fbdev_ttm_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_driver_legacy_fb_format(dev, sizes->surface_bpp,88 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_ttm_fb_ops;113 114 /* screen */115 info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;116 info->screen_buffer = 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 130err_drm_fb_helper_release_info:131 drm_fb_helper_release_info(fb_helper);132err_vfree:133 vfree(screen_buffer);134err_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 141static void drm_fbdev_ttm_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 180static int drm_fbdev_ttm_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 while189 * flushing the shadow buffer. In the general case, concurrent190 * modesetting operations could try to move the buffer and would191 * fail. The modeset has to be serialized by acquiring the reservation192 * object of the underlying BO here.193 *194 * For fbdev emulation, we only have to protect against fbdev modeset195 * operations. Nothing else will involve the client buffer's BO. So it196 * is sufficient to acquire struct drm_fb_helper.lock here.197 */198 mutex_lock(&fb_helper->lock);199 200 ret = drm_client_buffer_vmap_local(buffer, &map);201 if (ret)202 goto out;203 204 dst = map;205 drm_fbdev_ttm_damage_blit_real(fb_helper, clip, &dst);206 207 drm_client_buffer_vunmap_local(buffer);208 209out:210 mutex_unlock(&fb_helper->lock);211 212 return ret;213}214 215static int drm_fbdev_ttm_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_ttm_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 238static const struct drm_fb_helper_funcs drm_fbdev_ttm_helper_funcs = {239 .fb_probe = drm_fbdev_ttm_helper_fb_probe,240 .fb_dirty = drm_fbdev_ttm_helper_fb_dirty,241};242 243static void drm_fbdev_ttm_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 256static int drm_fbdev_ttm_client_restore(struct drm_client_dev *client)257{258 drm_fb_helper_lastclose(client->dev);259 260 return 0;261}262 263static int drm_fbdev_ttm_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 285err_drm_fb_helper_fini:286 drm_fb_helper_fini(fb_helper);287err_drm_err:288 drm_err(dev, "fbdev: Failed to setup emulation (ret=%d)\n", ret);289 return ret;290}291 292static const struct drm_client_funcs drm_fbdev_ttm_client_funcs = {293 .owner = THIS_MODULE,294 .unregister = drm_fbdev_ttm_client_unregister,295 .restore = drm_fbdev_ttm_client_restore,296 .hotplug = drm_fbdev_ttm_client_hotplug,297};298 299/**300 * drm_fbdev_ttm_setup() - Setup fbdev emulation for TTM-based drivers301 * @dev: DRM device302 * @preferred_bpp: Preferred bits per pixel for the device.303 *304 * This function sets up fbdev emulation for TTM-based drivers that support305 * dumb buffers with a virtual address and that can be mmap'ed.306 * drm_fbdev_ttm_setup() shall be called after the DRM driver registered307 * the new DRM device with drm_dev_register().308 *309 * Restore, hotplug events and teardown are all taken care of. Drivers that do310 * 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, fbdev emulation314 * uses a shadow buffer in system memory. The implementation blits the shadow315 * 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 */322void drm_fbdev_ttm_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_ttm_helper_funcs);334 335 ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_ttm_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 345err_drm_client_init:346 drm_fb_helper_unprepare(fb_helper);347 kfree(fb_helper);348 return;349}350EXPORT_SYMBOL(drm_fbdev_ttm_setup);351