Add generic fbdev emulation which uses a drm_file to get a dumb_buffer and drm_framebuffer. The buffer is exported and vmap/mmap called on the dma-buf.
Signed-off-by: Noralf Trønnes noralf@tronnes.org --- drivers/gpu/drm/drm_fb_helper.c | 289 ++++++++++++++++++++++++++++++++++++++++ include/drm/drm_fb_helper.h | 33 +++++ 2 files changed, 322 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index f9dcc7a5761f..d51bd5b1ecf1 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -30,6 +30,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/console.h> +#include <linux/dma-buf.h> #include <linux/kernel.h> #include <linux/sysrq.h> #include <linux/slab.h> @@ -43,6 +44,7 @@
#include "drm_crtc_internal.h" #include "drm_crtc_helper_internal.h" +#include "drm_internal.h"
static bool drm_fbdev_emulation = true; module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600); @@ -2975,6 +2977,293 @@ void drm_fb_helper_output_poll_changed(struct drm_device *dev) } EXPORT_SYMBOL(drm_fb_helper_output_poll_changed);
+static int drm_fb_helper_generic_vmap(struct drm_fb_helper *fb_helper) +{ + struct drm_prime_handle prime_args = { + .handle = fb_helper->dumb_handle, + }; + struct dma_buf *dma_buf; + void *vaddr; + int ret; + + ret = drm_prime_handle_to_fd_ioctl(fb_helper->dev, &prime_args, + fb_helper->file); + if (ret) + return ret; + + dma_buf = dma_buf_get(prime_args.fd); + if (WARN_ON(IS_ERR(dma_buf))) + return PTR_ERR(dma_buf); + + /* drop the ref we picked up in handle_to_fd */ + dma_buf_put(dma_buf); + + vaddr = dma_buf_vmap(dma_buf); + if (!vaddr) { + ret = -ENOMEM; + goto err_remove_handle; + } + + if (fb_helper->fbdev->fbdefio) + fb_deferred_io_init(fb_helper->fbdev); + + fb_helper->fbdev->screen_buffer = vaddr; + fb_helper->dma_buf = dma_buf; + + return 0; + +err_remove_handle: + drm_prime_remove_buf_handle_locked(&fb_helper->file->prime, + fb_helper->dma_buf); + dma_buf_put(dma_buf); + + return ret; +} + +static void drm_fb_helper_generic_vunmap(struct drm_fb_helper *fb_helper) +{ + if (fb_helper->fbdev->fbdefio) { + cancel_delayed_work_sync(&fb_helper->fbdev->deferred_work); + cancel_work_sync(&fb_helper->dirty_work); + fb_deferred_io_cleanup(fb_helper->fbdev); + } + + dma_buf_vunmap(fb_helper->dma_buf, fb_helper->fbdev->screen_buffer); + fb_helper->fbdev->screen_buffer = NULL; + + drm_prime_remove_buf_handle_locked(&fb_helper->file->prime, + fb_helper->dma_buf); + dma_buf_put(fb_helper->dma_buf); + fb_helper->dma_buf = NULL; +} + +static int drm_fb_helper_generic_fb_open(struct fb_info *info, int user) +{ + struct drm_fb_helper *fb_helper = info->par; + int ret; + + ret = drm_fb_helper_fb_open(info, user); + if (ret) + return ret; + + if (!fb_helper->fbdev->screen_buffer) { + /* + * Exporting a buffer to get a virtual address results in + * dma-buf pinning the driver module. This means that we have + * to vmap/vunmap in open/close to be able to unload the driver + * module. + */ + ret = drm_fb_helper_generic_vmap(fb_helper); + if (ret) { + DRM_ERROR("fbdev: Failed to vmap buffer: %d\n", ret); + drm_fb_helper_fb_release(info, user); + return ret; + } + } + + return 0; +} + +static int drm_fb_helper_generic_fb_release(struct fb_info *info, int user) +{ + struct drm_fb_helper *fb_helper = info->par; + + drm_fb_helper_fb_release(info, user); + + if (!atomic_read(&fb_helper->open_count)) + drm_fb_helper_generic_vunmap(fb_helper); + + return 0; +} + +static int drm_fb_helper_generic_fb_mmap(struct fb_info *info, + struct vm_area_struct *vma) +{ + struct drm_fb_helper *fb_helper = info->par; + + return dma_buf_mmap(fb_helper->dma_buf, vma, 0); +} + +static struct fb_ops drm_fb_helper_generic_fbdev_ops = { + .owner = THIS_MODULE, + DRM_FB_HELPER_DEFAULT_OPS, + .fb_open = drm_fb_helper_generic_fb_open, + .fb_release = drm_fb_helper_generic_fb_release, + .fb_mmap = drm_fb_helper_generic_fb_mmap, + .fb_read = drm_fb_helper_sys_read, + .fb_write = drm_fb_helper_sys_write, + .fb_fillrect = drm_fb_helper_sys_fillrect, + .fb_copyarea = drm_fb_helper_sys_copyarea, + .fb_imageblit = drm_fb_helper_sys_imageblit, +}; + +static struct fb_deferred_io drm_fb_helper_generic_defio = { + .delay = HZ / 20, + .deferred_io = drm_fb_helper_deferred_io, +}; + +static int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper, + struct drm_fb_helper_surface_size *sizes) +{ + struct drm_mode_create_dumb dumb_args = { 0 }; + struct drm_mode_fb_cmd2 fb_args = { 0 }; + struct drm_device *dev = fb_helper->dev; + struct drm_framebuffer *fb; + struct drm_file *file; + struct fb_info *fbi; + int ret; + + DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d)\n", + sizes->surface_width, sizes->surface_height, + sizes->surface_bpp); + + file = drm_file_alloc(dev->primary); + if (IS_ERR(file)) + return PTR_ERR(file); + + drm_dropmaster_ioctl(dev, NULL, file); + + dumb_args.width = sizes->surface_width; + dumb_args.height = sizes->surface_height; + dumb_args.bpp = sizes->surface_bpp; + + ret = drm_mode_create_dumb_ioctl(dev, &dumb_args, file); + if (ret) + goto err_free_file; + + fb_args.width = dumb_args.width; + fb_args.height = dumb_args.height; + fb_args.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp, + sizes->surface_depth); + fb_args.handles[0] = dumb_args.handle; + fb_args.pitches[0] = dumb_args.pitch; + + ret = drm_mode_addfb2(dev, &fb_args, file); + if (ret) + goto err_free_file; + + fb = drm_framebuffer_lookup(dev, file, fb_args.fb_id); + if (!fb) { + ret = -ENOENT; + goto err_free_file; + } + + /* drop the reference we picked up in framebuffer lookup */ + drm_framebuffer_put(fb); + + fb_helper->dumb_handle = dumb_args.handle; + fb_helper->file = file; + fb_helper->fb = fb; + + fbi = drm_fb_helper_alloc_fbi(fb_helper); + if (IS_ERR(fbi)) { + ret = PTR_ERR(fbi); + goto err_free_file; + } + + fbi->par = fb_helper; + fbi->fbops = &drm_fb_helper_generic_fbdev_ops; + fbi->screen_size = fb->height * fb->pitches[0]; + fbi->fix.smem_len = fbi->screen_size; + strcpy(fbi->fix.id, "generic"); + + drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->format->depth); + drm_fb_helper_fill_var(fbi, fb_helper, sizes->fb_width, sizes->fb_height); + + if (fb->funcs->dirty) { + struct fb_ops *fbops; + + /* + * fb_deferred_io_cleanup() clears &fbops->fb_mmap so a per + * instance version is necessary. + */ + fbops = kzalloc(sizeof(*fbops), GFP_KERNEL); + if (!fbops) { + ret = -ENOMEM; + goto err_fb_info_destroy; + } + + *fbops = *fbi->fbops; + fbi->fbops = fbops; + fbi->fbdefio = &drm_fb_helper_generic_defio; + } + + atomic_set(&fb_helper->open_count, 0); + + return 0; + +err_fb_info_destroy: + drm_fb_helper_fini(fb_helper); +err_free_file: + drm_file_free(file); + + return ret; +} + +static void drm_fb_helper_generic_release(struct drm_fb_helper *fb_helper) +{ + struct fb_ops *fbops = NULL; + + if (fb_helper->fbdev->fbdefio) + fbops = fb_helper->fbdev->fbops; + + drm_fb_helper_fini(fb_helper); + drm_file_free(fb_helper->file); + + kfree(fb_helper); + kfree(fbops); +} + +static const struct drm_fb_helper_funcs drm_fb_helper_generic_funcs = { + .fb_probe = drm_fb_helper_generic_probe, + .restore = drm_fb_helper_restore_fbdev_mode_unlocked, + .hotplug_event = drm_fb_helper_hotplug_event, + .unregister = drm_fb_helper_unregister_fbi, + .release = drm_fb_helper_generic_release, +}; + +/** + * drm_fb_helper_generic_fbdev_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. + * @max_conn_count: Maximum number of connectors. + * @dev->mode_config.num_connector is used if this is zero. + * + * This function sets up generic fbdev emulation for drivers that supports + * dumb buffers and provides exported buffers with a virtual address. + * The driver doesn't have to anything else than to call this function, + * restore, hotplug events and teardown are all taken care of. + * + * Returns: + * Zero on success or negative error code on failure. + */ +int drm_fb_helper_generic_fbdev_setup(struct drm_device *dev, + unsigned int preferred_bpp, + unsigned int max_conn_count) +{ + struct drm_fb_helper *fb_helper; + int ret; + + if (!drm_fbdev_emulation) + return 0; + + fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL); + if (!fb_helper) + return -ENOMEM; + + ret = drm_fb_helper_fbdev_setup(dev, fb_helper, + &drm_fb_helper_generic_funcs, + preferred_bpp, max_conn_count); + if (ret) { + kfree(fb_helper); + return ret; + } + + return 0; +} +EXPORT_SYMBOL(drm_fb_helper_generic_fbdev_setup); + /* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT) * but the module doesn't depend on any fb console symbols. At least * attempt to load fbcon to avoid leaving the system without a usable console. diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index f5ea79bbb831..38738a1abad7 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -279,6 +279,28 @@ struct drm_fb_helper { * initial value to 0 themselves. */ atomic_t open_count; + + /** + * @file: + * + * Optional DRM file. Used by the generic fbdev code. + */ + struct drm_file *file; + + /** + * @dumb_handle: + * + * Optional dumb buffer handle. Used by the generic fbdev code. + */ + u32 dumb_handle; + + /** + * @dma_buf: + * + * Optional pointer to a DMA buffer object. + * Used by the generic fbdev code. + */ + struct dma_buf *dma_buf; };
/** @@ -382,6 +404,10 @@ void drm_fb_helper_fbdev_teardown(struct drm_device *dev);
void drm_fb_helper_lastclose(struct drm_device *dev); void drm_fb_helper_output_poll_changed(struct drm_device *dev); + +int drm_fb_helper_generic_fbdev_setup(struct drm_device *dev, + unsigned int preferred_bpp, + unsigned int max_conn_count); #else static inline void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper, @@ -626,6 +652,13 @@ static inline void drm_fb_helper_output_poll_changed(struct drm_device *dev) { }
+static inline int +drm_fb_helper_generic_fbdev_setup(struct drm_device *dev, + unsigned int preferred_bpp, + unsigned int max_conn_count) +{ + return 0; +} #endif
static inline int