This library provides helpers for drivers that don't subclass drm_framebuffer and are backed by drm_gem_object. The code is taken from drm_fb_cma_helper.
Signed-off-by: Noralf Trønnes noralf@tronnes.org Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- Documentation/gpu/drm-kms-helpers.rst | 9 + drivers/gpu/drm/Makefile | 2 +- drivers/gpu/drm/drm_gem_framebuffer_helper.c | 283 +++++++++++++++++++++++++++ include/drm/drm_framebuffer.h | 7 + include/drm/drm_gem_framebuffer_helper.h | 37 ++++ 5 files changed, 337 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/drm_gem_framebuffer_helper.c create mode 100644 include/drm/drm_gem_framebuffer_helper.h
diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst index 7c5e254..13dd237 100644 --- a/Documentation/gpu/drm-kms-helpers.rst +++ b/Documentation/gpu/drm-kms-helpers.rst @@ -296,3 +296,12 @@ Auxiliary Modeset Helpers
.. kernel-doc:: drivers/gpu/drm/drm_modeset_helper.c :export: + +Framebuffer GEM Helper Reference +================================ + +.. kernel-doc:: drivers/gpu/drm/drm_gem_framebuffer_helper.c + :doc: overview + +.. kernel-doc:: drivers/gpu/drm/drm_gem_framebuffer_helper.c + :export: diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 24a066e..a8acc19 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -33,7 +33,7 @@ drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \ drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \ drm_kms_helper_common.o drm_dp_dual_mode_helper.o \ drm_simple_kms_helper.o drm_modeset_helper.o \ - drm_scdc_helper.o + drm_scdc_helper.o drm_gem_framebuffer_helper.o
drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c new file mode 100644 index 0000000..068a630 --- /dev/null +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c @@ -0,0 +1,283 @@ +/* + * drm gem framebuffer helper functions + * + * Copyright (C) 2017 Noralf Trønnes + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/dma-buf.h> +#include <linux/dma-fence.h> +#include <linux/reservation.h> +#include <linux/slab.h> + +#include <drm/drmP.h> +#include <drm/drm_atomic.h> +#include <drm/drm_fb_helper.h> +#include <drm/drm_fourcc.h> +#include <drm/drm_framebuffer.h> +#include <drm/drm_gem.h> +#include <drm/drm_gem_framebuffer_helper.h> +#include <drm/drm_modeset_helper.h> + +/** + * DOC: overview + * + * This library provides helpers for drivers that don't subclass + * &drm_framebuffer and and use &drm_gem_object for their backing storage. + * + * Drivers without additional needs to validate framebuffers can simply use + * drm_gem_fb_create() and everything is wired up automatically. But all + * parts can be used individually. + */ + +/** + * drm_gem_fb_get_obj() - Get GEM object for framebuffer + * @fb: The framebuffer + * @plane: Which plane + * + * Returns the GEM object for given framebuffer. + */ +struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb, + unsigned int plane) +{ + if (plane >= 4) + return NULL; + + return fb->obj[plane]; +} +EXPORT_SYMBOL_GPL(drm_gem_fb_get_obj); + +static struct drm_framebuffer * +drm_gem_fb_alloc(struct drm_device *dev, + const struct drm_mode_fb_cmd2 *mode_cmd, + struct drm_gem_object **obj, unsigned int num_planes, + const struct drm_framebuffer_funcs *funcs) +{ + struct drm_framebuffer *fb; + int ret, i; + + fb = kzalloc(sizeof(*fb), GFP_KERNEL); + if (!fb) + return ERR_PTR(-ENOMEM); + + drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd); + + for (i = 0; i < num_planes; i++) + fb->obj[i] = obj[i]; + + ret = drm_framebuffer_init(dev, fb, funcs); + if (ret) { + DRM_DEV_ERROR(dev->dev, "Failed to init framebuffer: %d\n", + ret); + kfree(fb); + return ERR_PTR(ret); + } + + return fb; +} + +/** + * drm_gem_fb_destroy - Free GEM backed framebuffer + * @fb: DRM framebuffer + * + * Frees a GEM backed framebuffer with it's backing buffer(s) and the structure + * itself. Drivers can use this as their &drm_framebuffer_funcs->destroy + * callback. + */ +void drm_gem_fb_destroy(struct drm_framebuffer *fb) +{ + int i; + + for (i = 0; i < 4; i++) + drm_gem_object_put_unlocked(fb->obj[i]); + + drm_framebuffer_cleanup(fb); + kfree(fb); +} +EXPORT_SYMBOL(drm_gem_fb_destroy); + +/** + * drm_gem_fb_create_handle - Create handle for GEM backed framebuffer + * @fb: DRM framebuffer + * @file: drm file + * @handle: handle created + * + * Drivers can use this as their &drm_framebuffer_funcs->create_handle + * callback. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file, + unsigned int *handle) +{ + return drm_gem_handle_create(file, fb->obj[0], handle); +} +EXPORT_SYMBOL(drm_gem_fb_create_handle); + +/** + * drm_gem_fb_create_with_funcs() - helper function for the + * &drm_mode_config_funcs.fb_create + * callback + * @dev: DRM device + * @file: drm file for the ioctl call + * @mode_cmd: metadata from the userspace fb creation request + * @funcs: vtable to be used for the new framebuffer object + * + * This can be used to set &drm_framebuffer_funcs for drivers that need the + * &drm_framebuffer_funcs.dirty callback. Use drm_gem_fb_create() if you don't + * need to change &drm_framebuffer_funcs. + * The function does buffer size validation. + */ +struct drm_framebuffer * +drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file, + const struct drm_mode_fb_cmd2 *mode_cmd, + const struct drm_framebuffer_funcs *funcs) +{ + const struct drm_format_info *info; + struct drm_gem_object *objs[4]; + struct drm_framebuffer *fb; + int ret, i; + + info = drm_get_format_info(dev, mode_cmd); + if (!info) + return ERR_PTR(-EINVAL); + + for (i = 0; i < info->num_planes; i++) { + unsigned int width = mode_cmd->width / (i ? info->hsub : 1); + unsigned int height = mode_cmd->height / (i ? info->vsub : 1); + unsigned int min_size; + + objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]); + if (!objs[i]) { + DRM_DEV_ERROR(dev->dev, "Failed to lookup GEM\n"); + ret = -ENOENT; + goto err_gem_object_put; + } + + min_size = (height - 1) * mode_cmd->pitches[i] + + width * info->cpp[i] + + mode_cmd->offsets[i]; + + if (objs[i]->size < min_size) { + drm_gem_object_put_unlocked(objs[i]); + ret = -EINVAL; + goto err_gem_object_put; + } + } + + fb = drm_gem_fb_alloc(dev, mode_cmd, objs, i, funcs); + if (IS_ERR(fb)) { + ret = PTR_ERR(fb); + goto err_gem_object_put; + } + + return fb; + +err_gem_object_put: + for (i--; i >= 0; i--) + drm_gem_object_put_unlocked(objs[i]); + + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_funcs); + +static const struct drm_framebuffer_funcs drm_gem_fb_funcs = { + .destroy = drm_gem_fb_destroy, + .create_handle = drm_gem_fb_create_handle, +}; + +/** + * drm_gem_fb_create() - &drm_mode_config_funcs.fb_create callback function + * @dev: DRM device + * @file: drm file for the ioctl call + * @mode_cmd: metadata from the userspace fb creation request + * + * If your hardware has special alignment or pitch requirements these should be + * checked before calling this function. The function does buffer size + * validation. Use drm_gem_fb_create_with_funcs() if you need to set + * &drm_framebuffer_funcs.dirty. + */ +struct drm_framebuffer * +drm_gem_fb_create(struct drm_device *dev, struct drm_file *file, + const struct drm_mode_fb_cmd2 *mode_cmd) +{ + return drm_gem_fb_create_with_funcs(dev, file, mode_cmd, + &drm_gem_fb_funcs); +} +EXPORT_SYMBOL_GPL(drm_gem_fb_create); + +/** + * drm_gem_fb_prepare_fb() - Prepare gem framebuffer + * @plane: Which plane + * @state: Plane state attach fence to + * + * This can be used as the &drm_plane_helper_funcs.prepare_fb hook. + * + * This function checks if the plane FB has an dma-buf attached, extracts + * the exclusive fence and attaches it to plane state for the atomic helper + * to wait on. + * + * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple + * gem based framebuffer drivers which have their buffers always pinned in + * memory. + */ +int drm_gem_fb_prepare_fb(struct drm_plane *plane, + struct drm_plane_state *state) +{ + struct dma_buf *dma_buf; + struct dma_fence *fence; + + if ((plane->state->fb == state->fb) || !state->fb) + return 0; + + dma_buf = drm_gem_fb_get_obj(state->fb, 0)->dma_buf; + if (dma_buf) { + fence = reservation_object_get_excl_rcu(dma_buf->resv); + drm_atomic_set_fence_for_plane(state, fence); + } + + return 0; +} +EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb); + +/** + * drm_gem_fbdev_fb_create - Create a drm_framebuffer for fbdev emulation + * @dev: DRM device + * @sizes: fbdev size description + * @pitch_align: optional pitch alignment + * @obj: GEM object backing the framebuffer + * @funcs: vtable to be used for the new framebuffer object + * + * This function creates a framebuffer for use with fbdev emulation. + * + * Returns: + * Pointer to a drm_framebuffer on success or an error pointer on failure. + */ +struct drm_framebuffer * +drm_gem_fbdev_fb_create(struct drm_device *dev, + struct drm_fb_helper_surface_size *sizes, + unsigned int pitch_align, struct drm_gem_object *obj, + const struct drm_framebuffer_funcs *funcs) +{ + struct drm_mode_fb_cmd2 mode_cmd = { 0 }; + + mode_cmd.width = sizes->surface_width; + mode_cmd.height = sizes->surface_height; + mode_cmd.pitches[0] = sizes->surface_width * + DIV_ROUND_UP(sizes->surface_bpp, 8); + if (pitch_align) + mode_cmd.pitches[0] = roundup(mode_cmd.pitches[0], + pitch_align); + mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp, + sizes->surface_depth); + if (obj->size < mode_cmd.pitches[0] * mode_cmd.height) + return ERR_PTR(-EINVAL); + + return drm_gem_fb_alloc(dev, &mode_cmd, &obj, 1, funcs); +} +EXPORT_SYMBOL(drm_gem_fbdev_fb_create); diff --git a/include/drm/drm_framebuffer.h b/include/drm/drm_framebuffer.h index 5244f05..b6996dd 100644 --- a/include/drm/drm_framebuffer.h +++ b/include/drm/drm_framebuffer.h @@ -190,6 +190,13 @@ struct drm_framebuffer { * @filp_head: Placed on &drm_file.fbs, protected by &drm_file.fbs_lock. */ struct list_head filp_head; + /** + * @obj: GEM objects backing the framebuffer, one per plane (optional). + * + * This is used by the GEM framebuffer helpers, see e.g. + * drm_gem_fb_create(). + */ + struct drm_gem_object *obj[4]; };
#define obj_to_fb(x) container_of(x, struct drm_framebuffer, base) diff --git a/include/drm/drm_gem_framebuffer_helper.h b/include/drm/drm_gem_framebuffer_helper.h new file mode 100644 index 0000000..db9cfa0 --- /dev/null +++ b/include/drm/drm_gem_framebuffer_helper.h @@ -0,0 +1,37 @@ +#ifndef __DRM_GEM_FB_HELPER_H__ +#define __DRM_GEM_FB_HELPER_H__ + +struct drm_device; +struct drm_file; +struct drm_fb_helper_surface_size; +struct drm_framebuffer; +struct drm_framebuffer_funcs; +struct drm_gem_object; +struct drm_mode_fb_cmd2; +struct drm_plane; +struct drm_plane_state; + +struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb, + unsigned int plane); +void drm_gem_fb_destroy(struct drm_framebuffer *fb); +int drm_gem_fb_create_handle(struct drm_framebuffer *fb, struct drm_file *file, + unsigned int *handle); + +struct drm_framebuffer * +drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file, + const struct drm_mode_fb_cmd2 *mode_cmd, + const struct drm_framebuffer_funcs *funcs); +struct drm_framebuffer * +drm_gem_fb_create(struct drm_device *dev, struct drm_file *file, + const struct drm_mode_fb_cmd2 *mode_cmd); + +int drm_gem_fb_prepare_fb(struct drm_plane *plane, + struct drm_plane_state *state); + +struct drm_framebuffer * +drm_gem_fbdev_fb_create(struct drm_device *dev, + struct drm_fb_helper_surface_size *sizes, + unsigned int pitch_align, struct drm_gem_object *obj, + const struct drm_framebuffer_funcs *funcs); + +#endif