diff options
Diffstat (limited to 'drivers/gpu/drm/drm_fbdev_generic.c')
| -rw-r--r-- | drivers/gpu/drm/drm_fbdev_generic.c | 493 |
1 files changed, 493 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c new file mode 100644 index 000000000000..2d6083ad2e3c --- /dev/null +++ b/drivers/gpu/drm/drm_fbdev_generic.c @@ -0,0 +1,493 @@ +// SPDX-License-Identifier: MIT + +#include <linux/moduleparam.h> + +#include <drm/drm_crtc_helper.h> +#include <drm/drm_drv.h> +#include <drm/drm_fb_helper.h> +#include <drm/drm_framebuffer.h> +#include <drm/drm_print.h> + +#include <drm/drm_fbdev_generic.h> + +static bool drm_fbdev_use_shadow_fb(struct drm_fb_helper *fb_helper) +{ + struct drm_device *dev = fb_helper->dev; + struct drm_framebuffer *fb = fb_helper->fb; + + return dev->mode_config.prefer_shadow_fbdev || + dev->mode_config.prefer_shadow || + fb->funcs->dirty; +} + +/* @user: 1=userspace, 0=fbcon */ +static int drm_fbdev_fb_open(struct fb_info *info, int user) +{ + struct drm_fb_helper *fb_helper = info->par; + + /* No need to take a ref for fbcon because it unbinds on unregister */ + if (user && !try_module_get(fb_helper->dev->driver->fops->owner)) + return -ENODEV; + + return 0; +} + +static int drm_fbdev_fb_release(struct fb_info *info, int user) +{ + struct drm_fb_helper *fb_helper = info->par; + + if (user) + module_put(fb_helper->dev->driver->fops->owner); + + return 0; +} + +static void drm_fbdev_cleanup(struct drm_fb_helper *fb_helper) +{ + struct fb_info *fbi = fb_helper->info; + void *shadow = NULL; + + if (!fb_helper->dev) + return; + + if (fbi) { + if (fbi->fbdefio) + fb_deferred_io_cleanup(fbi); + if (drm_fbdev_use_shadow_fb(fb_helper)) + shadow = fbi->screen_buffer; + } + + drm_fb_helper_fini(fb_helper); + + if (shadow) + vfree(shadow); + else if (fb_helper->buffer) + drm_client_buffer_vunmap(fb_helper->buffer); + + drm_client_framebuffer_delete(fb_helper->buffer); +} + +static void drm_fbdev_release(struct drm_fb_helper *fb_helper) +{ + drm_fbdev_cleanup(fb_helper); + drm_client_release(&fb_helper->client); + kfree(fb_helper); +} + +/* + * fb_ops.fb_destroy is called by the last put_fb_info() call at the end of + * unregister_framebuffer() or fb_release(). + */ +static void drm_fbdev_fb_destroy(struct fb_info *info) +{ + drm_fbdev_release(info->par); +} + +static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) +{ + struct drm_fb_helper *fb_helper = info->par; + + if (drm_fbdev_use_shadow_fb(fb_helper)) + return fb_deferred_io_mmap(info, vma); + else if (fb_helper->dev->driver->gem_prime_mmap) + return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma); + else + return -ENODEV; +} + +static bool drm_fbdev_use_iomem(struct fb_info *info) +{ + struct drm_fb_helper *fb_helper = info->par; + struct drm_client_buffer *buffer = fb_helper->buffer; + + return !drm_fbdev_use_shadow_fb(fb_helper) && buffer->map.is_iomem; +} + +static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf, + size_t count, loff_t *ppos) +{ + ssize_t ret; + + if (drm_fbdev_use_iomem(info)) + ret = drm_fb_helper_cfb_read(info, buf, count, ppos); + else + ret = drm_fb_helper_sys_read(info, buf, count, ppos); + + return ret; +} + +static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf, + size_t count, loff_t *ppos) +{ + ssize_t ret; + + if (drm_fbdev_use_iomem(info)) + ret = drm_fb_helper_cfb_write(info, buf, count, ppos); + else + ret = drm_fb_helper_sys_write(info, buf, count, ppos); + + return ret; +} + +static void drm_fbdev_fb_fillrect(struct fb_info *info, + const struct fb_fillrect *rect) +{ + if (drm_fbdev_use_iomem(info)) + drm_fb_helper_cfb_fillrect(info, rect); + else + drm_fb_helper_sys_fillrect(info, rect); +} + +static void drm_fbdev_fb_copyarea(struct fb_info *info, + const struct fb_copyarea *area) +{ + if (drm_fbdev_use_iomem(info)) + drm_fb_helper_cfb_copyarea(info, area); + else + drm_fb_helper_sys_copyarea(info, area); +} + +static void drm_fbdev_fb_imageblit(struct fb_info *info, + const struct fb_image *image) +{ + if (drm_fbdev_use_iomem(info)) + drm_fb_helper_cfb_imageblit(info, image); + else + drm_fb_helper_sys_imageblit(info, image); +} + +static const struct fb_ops drm_fbdev_fb_ops = { + .owner = THIS_MODULE, + DRM_FB_HELPER_DEFAULT_OPS, + .fb_open = drm_fbdev_fb_open, + .fb_release = drm_fbdev_fb_release, + .fb_destroy = drm_fbdev_fb_destroy, + .fb_mmap = drm_fbdev_fb_mmap, + .fb_read = drm_fbdev_fb_read, + .fb_write = drm_fbdev_fb_write, + .fb_fillrect = drm_fbdev_fb_fillrect, + .fb_copyarea = drm_fbdev_fb_copyarea, + .fb_imageblit = drm_fbdev_fb_imageblit, +}; + +static struct fb_deferred_io drm_fbdev_defio = { + .delay = HZ / 20, + .deferred_io = drm_fb_helper_deferred_io, +}; + +/* + * This function uses the client API to create a framebuffer backed by a dumb buffer. + */ +static int drm_fbdev_fb_probe(struct drm_fb_helper *fb_helper, + struct drm_fb_helper_surface_size *sizes) +{ + struct drm_client_dev *client = &fb_helper->client; + struct drm_device *dev = fb_helper->dev; + struct drm_client_buffer *buffer; + struct drm_framebuffer *fb; + struct fb_info *fbi; + u32 format; + struct iosys_map map; + int ret; + + drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n", + sizes->surface_width, sizes->surface_height, + sizes->surface_bpp); + + format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth); + buffer = drm_client_framebuffer_create(client, sizes->surface_width, + sizes->surface_height, format); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); + + fb_helper->buffer = buffer; + fb_helper->fb = buffer->fb; + fb = buffer->fb; + + fbi = drm_fb_helper_alloc_info(fb_helper); + if (IS_ERR(fbi)) + return PTR_ERR(fbi); + + fbi->fbops = &drm_fbdev_fb_ops; + fbi->screen_size = sizes->surface_height * fb->pitches[0]; + fbi->fix.smem_len = fbi->screen_size; + fbi->flags = FBINFO_DEFAULT; + + drm_fb_helper_fill_info(fbi, fb_helper, sizes); + + if (drm_fbdev_use_shadow_fb(fb_helper)) { + fbi->screen_buffer = vzalloc(fbi->screen_size); + if (!fbi->screen_buffer) + return -ENOMEM; + fbi->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST; + + fbi->fbdefio = &drm_fbdev_defio; + fb_deferred_io_init(fbi); + } else { + /* buffer is mapped for HW framebuffer */ + ret = drm_client_buffer_vmap(fb_helper->buffer, &map); + if (ret) + return ret; + if (map.is_iomem) { + fbi->screen_base = map.vaddr_iomem; + } else { + fbi->screen_buffer = map.vaddr; + fbi->flags |= FBINFO_VIRTFB; + } + + /* + * Shamelessly leak the physical address to user-space. As + * page_to_phys() is undefined for I/O memory, warn in this + * case. + */ +#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM) + if (fb_helper->hint_leak_smem_start && fbi->fix.smem_start == 0 && + !drm_WARN_ON_ONCE(dev, map.is_iomem)) + fbi->fix.smem_start = + page_to_phys(virt_to_page(fbi->screen_buffer)); +#endif + } + + return 0; +} + +static void drm_fbdev_damage_blit_real(struct drm_fb_helper *fb_helper, + struct drm_clip_rect *clip, + struct iosys_map *dst) +{ + struct drm_framebuffer *fb = fb_helper->fb; + size_t offset = clip->y1 * fb->pitches[0]; + size_t len = clip->x2 - clip->x1; + unsigned int y; + void *src; + + switch (drm_format_info_bpp(fb->format, 0)) { + case 1: + offset += clip->x1 / 8; + len = DIV_ROUND_UP(len + clip->x1 % 8, 8); + break; + case 2: + offset += clip->x1 / 4; + len = DIV_ROUND_UP(len + clip->x1 % 4, 4); + break; + case 4: + offset += clip->x1 / 2; + len = DIV_ROUND_UP(len + clip->x1 % 2, 2); + break; + default: + offset += clip->x1 * fb->format->cpp[0]; + len *= fb->format->cpp[0]; + break; + } + + src = fb_helper->info->screen_buffer + offset; + iosys_map_incr(dst, offset); /* go to first pixel within clip rect */ + + for (y = clip->y1; y < clip->y2; y++) { + iosys_map_memcpy_to(dst, 0, src, len); + iosys_map_incr(dst, fb->pitches[0]); + src += fb->pitches[0]; + } +} + +static int drm_fbdev_damage_blit(struct drm_fb_helper *fb_helper, + struct drm_clip_rect *clip) +{ + struct drm_client_buffer *buffer = fb_helper->buffer; + struct iosys_map map, dst; + int ret; + + /* + * We have to pin the client buffer to its current location while + * flushing the shadow buffer. In the general case, concurrent + * modesetting operations could try to move the buffer and would + * fail. The modeset has to be serialized by acquiring the reservation + * object of the underlying BO here. + * + * For fbdev emulation, we only have to protect against fbdev modeset + * operations. Nothing else will involve the client buffer's BO. So it + * is sufficient to acquire struct drm_fb_helper.lock here. + */ + mutex_lock(&fb_helper->lock); + + ret = drm_client_buffer_vmap(buffer, &map); + if (ret) + goto out; + + dst = map; + drm_fbdev_damage_blit_real(fb_helper, clip, &dst); + + drm_client_buffer_vunmap(buffer); + +out: + mutex_unlock(&fb_helper->lock); + + return ret; +} + +static int drm_fbdev_fb_dirty(struct drm_fb_helper *helper, struct drm_clip_rect *clip) +{ + struct drm_device *dev = helper->dev; + int ret; + + if (!drm_fbdev_use_shadow_fb(helper)) + return 0; + + /* Call damage handlers only if necessary */ + if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2)) + return 0; + + if (helper->buffer) { + ret = drm_fbdev_damage_blit(helper, clip); + if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret)) + return ret; + } + + if (helper->fb->funcs->dirty) { + ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1); + if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret)) + return ret; + } + + return 0; +} + +static const struct drm_fb_helper_funcs drm_fb_helper_generic_funcs = { + .fb_probe = drm_fbdev_fb_probe, + .fb_dirty = drm_fbdev_fb_dirty, +}; + +static void drm_fbdev_client_unregister(struct drm_client_dev *client) +{ + struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); + + if (fb_helper->info) + /* drm_fbdev_fb_destroy() takes care of cleanup */ + drm_fb_helper_unregister_info(fb_helper); + else + drm_fbdev_release(fb_helper); +} + +static int drm_fbdev_client_restore(struct drm_client_dev *client) +{ + drm_fb_helper_lastclose(client->dev); + + return 0; +} + +static int drm_fbdev_client_hotplug(struct drm_client_dev *client) +{ + struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); + struct drm_device *dev = client->dev; + int ret; + + /* Setup is not retried if it has failed */ + if (!fb_helper->dev && fb_helper->funcs) + return 0; + + if (dev->fb_helper) + return drm_fb_helper_hotplug_event(dev->fb_helper); + + if (!dev->mode_config.num_connector) { + drm_dbg_kms(dev, "No connectors found, will not create framebuffer!\n"); + return 0; + } + + drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs); + + ret = drm_fb_helper_init(dev, fb_helper); + if (ret) + goto err; + + if (!drm_drv_uses_atomic_modeset(dev)) + drm_helper_disable_unused_functions(dev); + + ret = drm_fb_helper_initial_config(fb_helper, fb_helper->preferred_bpp); + if (ret) + goto err_cleanup; + + return 0; + +err_cleanup: + drm_fbdev_cleanup(fb_helper); +err: + fb_helper->dev = NULL; + fb_helper->info = NULL; + + drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret); + + return ret; +} + +static const struct drm_client_funcs drm_fbdev_client_funcs = { + .owner = THIS_MODULE, + .unregister = drm_fbdev_client_unregister, + .restore = drm_fbdev_client_restore, + .hotplug = drm_fbdev_client_hotplug, +}; + +/** + * drm_fbdev_generic_setup() - Setup generic fbdev emulation + * @dev: DRM device + * @preferred_bpp: Preferred bits per pixel for the device. + * @dev->mode_config.preferred_depth is used if this is zero. + * + * This function sets up generic fbdev emulation for drivers that supports + * dumb buffers with a virtual address and that can be mmap'ed. + * drm_fbdev_generic_setup() shall be called after the DRM driver registered + * the new DRM device with drm_dev_register(). + * + * Restore, hotplug events and teardown are all taken care of. Drivers that do + * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves. + * Simple drivers might use drm_mode_config_helper_suspend(). + * + * Drivers that set the dirty callback on their framebuffer will get a shadow + * fbdev buffer that is blitted onto the real buffer. This is done in order to + * make deferred I/O work with all kinds of buffers. A shadow buffer can be + * requested explicitly by setting struct drm_mode_config.prefer_shadow or + * struct drm_mode_config.prefer_shadow_fbdev to true beforehand. This is + * required to use generic fbdev emulation with SHMEM helpers. + * + * This function is safe to call even when there are no connectors present. + * Setup will be retried on the next hotplug event. + * + * The fbdev is destroyed by drm_dev_unregister(). + */ +void drm_fbdev_generic_setup(struct drm_device *dev, + unsigned int preferred_bpp) +{ + struct drm_fb_helper *fb_helper; + int ret; + + drm_WARN(dev, !dev->registered, "Device has not been registered.\n"); + drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n"); + + fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL); + if (!fb_helper) + return; + + ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs); + if (ret) { + kfree(fb_helper); + drm_err(dev, "Failed to register client: %d\n", ret); + return; + } + + /* + * FIXME: This mixes up depth with bpp, which results in a glorious + * mess, resulting in some drivers picking wrong fbdev defaults and + * others wrong preferred_depth defaults. + */ + if (!preferred_bpp) + preferred_bpp = dev->mode_config.preferred_depth; + if (!preferred_bpp) + preferred_bpp = 32; + fb_helper->preferred_bpp = preferred_bpp; + + ret = drm_fbdev_client_hotplug(&fb_helper->client); + if (ret) + drm_dbg_kms(dev, "client hotplug ret=%d\n", ret); + + drm_client_register(&fb_helper->client); +} +EXPORT_SYMBOL(drm_fbdev_generic_setup); |