Re: [RFC 2/7] drm: Add GEM backed framebuffer library

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@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