[RFC 2/7] drm: Add GEM backed framebuffer library
Noralf Trønnes
noralf at tronnes.org
Tue Jul 18 15:42:28 UTC 2017
Den 12.07.2017 15.46, skrev Noralf Trønnes:
> Add a library for drivers that can use a simple representation
> of a GEM backed framebuffer.
>
> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> ---
This patch adds a gem backed drm_framebuffer like this:
struct drm_fb_gem {
/**
* @base: Base DRM framebuffer
*/
struct drm_framebuffer base;
/**
* @obj: GEM object array backing the framebuffer. One object per
* plane.
*/
struct drm_gem_object *obj[4];
};
Now I wonder if it would be better to extend drm_framebuffer instead:
struct drm_framebuffer {
+ /**
+ * @obj: GEM objects backing the framebuffer, one per plane (optional).
+ */
+ struct drm_gem_object *obj[4];
};
The reason for this, is that I have looked through all drivers that
subclass drm_framebuffer and found this:
- 11 drivers just adds drm_gem_object
- 2 drivers adds drm_gem_object and some more
- 6 drivers adds drm_gem_object indirectly through their subclassed
drm_gem_object
- 3 drivers doesn't add drm_gem_object
Full details below:
Adds only drm_gem_object
------------------------
struct amdgpu_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
};
struct ast_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
};
struct bochs_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
};
struct cirrus_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
};
struct drm_fb_cma {
struct drm_framebuffer fb;
struct drm_gem_cma_object *obj[4];
};
struct hibmc_framebuffer {
struct drm_framebuffer fb;
struct drm_gem_object *obj;
};
struct mga_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
};
struct mtk_drm_fb {
struct drm_framebuffer base;
/* For now we only support a single plane */
struct drm_gem_object *gem_obj;
};
struct qxl_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
};
struct radeon_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
};
struct rockchip_drm_fb {
struct drm_framebuffer fb;
struct drm_gem_object *obj[ROCKCHIP_MAX_FB_BUFFER];
};
#define ROCKCHIP_MAX_FB_BUFFER 3
Adds drm_gem_object and some more
---------------------------------
struct msm_framebuffer {
struct drm_framebuffer base;
const struct msm_format *format;
struct drm_gem_object *planes[MAX_PLANE];
};
#define MAX_PLANE 4
struct virtio_gpu_framebuffer {
struct drm_framebuffer base;
struct drm_gem_object *obj;
int x1, y1, x2, y2; /* dirty rect */
spinlock_t dirty_lock;
uint32_t hw_res_handle;
};
Indirectly adds a drm_gem_object
--------------------------------
struct armada_framebuffer {
struct drm_framebuffer fb;
struct armada_gem_object *obj;
uint8_t fmt;
uint8_t mod;
};
struct exynos_drm_fb {
struct drm_framebuffer fb;
struct exynos_drm_gem *exynos_gem[MAX_FB_BUFFER];
dma_addr_t dma_addr[MAX_FB_BUFFER];
};
#define MAX_FB_BUFFER 4
struct intel_framebuffer {
struct drm_framebuffer base;
struct drm_i915_gem_object *obj;
struct intel_rotation_info rot_info;
/* for each plane in the normal GTT view */
struct {
unsigned int x, y;
} normal[2];
/* for each plane in the rotated GTT view */
struct {
unsigned int x, y;
unsigned int pitch; /* pixels */
} rotated[2];
};
struct nouveau_framebuffer {
struct drm_framebuffer base;
struct nouveau_bo *nvbo;
struct nvkm_vma vma;
u32 r_handle;
u32 r_format;
u32 r_pitch;
struct nvif_object h_base[4];
struct nvif_object h_core;
};
struct tegra_fb {
struct drm_framebuffer base;
struct tegra_bo **planes;
unsigned int num_planes;
};
struct udl_framebuffer {
struct drm_framebuffer base;
struct udl_gem_object *obj;
bool active_16; /* active on the 16-bit channel */
};
Does not add drm_gem_object
---------------------------
struct omap_framebuffer {
struct drm_framebuffer base;
int pin_count;
const struct drm_format_info *format;
enum omap_color_mode dss_format;
struct plane planes[2];
/* lock for pinning (pin_count and planes.paddr) */
struct mutex lock;
};
struct psb_framebuffer {
struct drm_framebuffer base;
struct address_space *addr_space;
struct fb_info *fbdev;
struct gtt_range *gtt;
};
struct vmw_framebuffer {
struct drm_framebuffer base;
int (*pin)(struct vmw_framebuffer *fb);
int (*unpin)(struct vmw_framebuffer *fb);
bool dmabuf;
struct ttm_base_object *user_obj;
uint32_t user_handle;
};
Noralf.
> drivers/gpu/drm/Makefile | 2 +-
> drivers/gpu/drm/drm_fb_gem_helper.c | 248 ++++++++++++++++++++++++++++++++++++
> include/drm/drm_fb_gem_helper.h | 64 ++++++++++
> 3 files changed, 313 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/drm_fb_gem_helper.c
> create mode 100644 include/drm/drm_fb_gem_helper.h
>
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 24a066e..83d8b09 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_fb_gem_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_fb_gem_helper.c b/drivers/gpu/drm/drm_fb_gem_helper.c
> new file mode 100644
> index 0000000..9a0da09
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_fb_gem_helper.c
> @@ -0,0 +1,248 @@
> +/*
> + * drm fb gem 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-mapping.h>
> +#include <linux/module.h>
> +#include <linux/reservation.h>
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_fb_helper.h>
> +#include <drm/drm_fb_gem_helper.h>
> +#include <drm/drm_gem.h>
> +
> +/**
> + * drm_fb_gem_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_fb_gem_get_obj(struct drm_framebuffer *fb,
> + unsigned int plane)
> +{
> + struct drm_fb_gem *fb_gem = to_fb_gem(fb);
> +
> + if (plane >= 4)
> + return NULL;
> +
> + return fb_gem->obj[plane];
> +}
> +EXPORT_SYMBOL_GPL(drm_fb_gem_get_obj);
> +
> +/**
> + * drm_fb_gem_alloc - Allocate GEM backed framebuffer
> + * @dev: DRM device
> + * @mode_cmd: metadata from the userspace fb creation request
> + * @obj: GEM object nacking the framebuffer
> + * @num_planes: Number of planes
> + * @funcs: vtable to be used for the new framebuffer object
> + *
> + * Returns:
> + * Allocated struct drm_fb_gem * or error encoded pointer.
> + */
> +struct drm_fb_gem *
> +drm_fb_gem_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_fb_gem *fb_gem;
> + int ret, i;
> +
> + fb_gem = kzalloc(sizeof(*fb_gem), GFP_KERNEL);
> + if (!fb_gem)
> + return ERR_PTR(-ENOMEM);
> +
> + drm_helper_mode_fill_fb_struct(dev, &fb_gem->base, mode_cmd);
> +
> + for (i = 0; i < num_planes; i++)
> + fb_gem->obj[i] = obj[i];
> +
> + ret = drm_framebuffer_init(dev, &fb_gem->base, funcs);
> + if (ret) {
> + dev_err(dev->dev, "Failed to initialize framebuffer: %d\n", ret);
> + kfree(fb_gem);
> + return ERR_PTR(ret);
> + }
> +
> + return fb_gem;
> +}
> +EXPORT_SYMBOL(drm_fb_gem_alloc);
> +
> +/**
> + * drm_fb_gem_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_fb_gem_destroy(struct drm_framebuffer *fb)
> +{
> + struct drm_fb_gem *fb_gem = to_fb_gem(fb);
> + int i;
> +
> + for (i = 0; i < 4; i++) {
> + if (fb_gem->obj[i])
> + drm_gem_object_put_unlocked(fb_gem->obj[i]);
> + }
> +
> + drm_framebuffer_cleanup(fb);
> + kfree(fb_gem);
> +}
> +EXPORT_SYMBOL(drm_fb_gem_destroy);
> +
> +/**
> + * drm_fb_gem_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_fb_gem_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
> + unsigned int *handle)
> +{
> + struct drm_fb_gem *fb_gem = to_fb_gem(fb);
> +
> + return drm_gem_handle_create(file, fb_gem->obj[0], handle);
> +}
> +EXPORT_SYMBOL(drm_fb_gem_create_handle);
> +
> +/**
> + * drm_fb_gem_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_fb_gem_create() if you don't
> + * need to change &drm_framebuffer_funcs.
> + */
> +struct drm_framebuffer *
> +drm_fb_gem_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_fb_gem *fb_gem;
> + 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]) {
> + dev_err(dev->dev, "Failed to lookup GEM object\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_gem = drm_fb_gem_alloc(dev, mode_cmd, objs, i, funcs);
> + if (IS_ERR(fb_gem)) {
> + ret = PTR_ERR(fb_gem);
> + goto err_gem_object_put;
> + }
> +
> + return &fb_gem->base;
> +
> +err_gem_object_put:
> + for (i--; i >= 0; i--)
> + drm_gem_object_put_unlocked(objs[i]);
> +
> + return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(drm_fb_gem_create_with_funcs);
> +
> +static struct drm_framebuffer_funcs drm_fb_gem_fb_funcs = {
> + .destroy = drm_fb_gem_destroy,
> + .create_handle = drm_fb_gem_create_handle,
> +};
> +
> +/**
> + * drm_fb_gem_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. Use drm_fb_gem_create_with_funcs() if
> + * you need to set &drm_framebuffer_funcs.dirty.
> + */
> +struct drm_framebuffer *
> +drm_fb_gem_create(struct drm_device *dev, struct drm_file *file,
> + const struct drm_mode_fb_cmd2 *mode_cmd)
> +{
> + return drm_fb_gem_create_with_funcs(dev, file, mode_cmd,
> + &drm_fb_gem_fb_funcs);
> +}
> +EXPORT_SYMBOL_GPL(drm_fb_gem_create);
> +
> +/**
> + * drm_fb_gem_prepare_fb() - Prepare gem framebuffer
> + * @plane: Which plane
> + * @state: Plane state attach fence to
> + *
> + * This should be set as the &struct 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 cleanup_fb for gem based framebuffer drivers.
> + */
> +int drm_fb_gem_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_fb_gem_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_fb_gem_prepare_fb);
> diff --git a/include/drm/drm_fb_gem_helper.h b/include/drm/drm_fb_gem_helper.h
> new file mode 100644
> index 0000000..405a1e1
> --- /dev/null
> +++ b/include/drm/drm_fb_gem_helper.h
> @@ -0,0 +1,64 @@
> +#ifndef __DRM_FB_GEM_HELPER_H__
> +#define __DRM_FB_GEM_HELPER_H__
> +
> +#include <drm/drm_framebuffer.h>
> +
> +struct drm_gem_shmem_object;
> +struct drm_mode_fb_cmd2;
> +struct drm_plane;
> +struct drm_plane_state;
> +
> +/**
> + * struct drm_fb_gem - GEM backed framebuffer
> + */
> +struct drm_fb_gem {
> + /**
> + * @base: Base DRM framebuffer
> + */
> + struct drm_framebuffer base;
> + /**
> + * @obj: GEM object array backing the framebuffer. One object per
> + * plane.
> + */
> + struct drm_gem_object *obj[4];
> +};
> +
> +static inline struct drm_fb_gem *to_fb_gem(struct drm_framebuffer *fb)
> +{
> + return container_of(fb, struct drm_fb_gem, base);
> +}
> +
> +struct drm_gem_object *drm_fb_gem_get_obj(struct drm_framebuffer *fb,
> + unsigned int plane);
> +struct drm_fb_gem *
> +drm_fb_gem_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);
> +void drm_fb_gem_destroy(struct drm_framebuffer *fb);
> +int drm_fb_gem_create_handle(struct drm_framebuffer *fb, struct drm_file *file,
> + unsigned int *handle);
> +
> +struct drm_framebuffer *
> +drm_fb_gem_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_fb_gem_create(struct drm_device *dev, struct drm_file *file,
> + const struct drm_mode_fb_cmd2 *mode_cmd);
> +
> +
> +int drm_fb_gem_prepare_fb(struct drm_plane *plane,
> + struct drm_plane_state *state);
> +
> +
> +
> +
> +#ifdef CONFIG_DEBUG_FS
> +struct seq_file;
> +
> +int drm_fb_gem_debugfs_show(struct seq_file *m, void *arg);
> +#endif
> +
> +#endif
> +
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