drm/amdgpu: Add documentation for PRIME related code (baca30fa) · Commits · e / devices / android_kernel_oneplus_sm7250

Documentation/gpu/amdgpu.rst

+14 −0

Original line number	Original line	Diff line number	Diff line
	@@ -4,3 +4,17 @@

	The drm/amdgpu driver supports all AMD Radeon GPUs based on the Graphics Core		The drm/amdgpu driver supports all AMD Radeon GPUs based on the Graphics Core
	Next (GCN) architecture.		Next (GCN) architecture.

			Core Driver Infrastructure
			==========================

			This section covers core driver infrastructure.

			PRIME Buffer Sharing
			--------------------

			.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
			:doc: PRIME Buffer Sharing

			.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
			:internal:

drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c

+119 −0

Original line number	Original line	Diff line number	Diff line
	@@ -23,6 +23,14 @@
	*		*
	* Authors: Alex Deucher		* Authors: Alex Deucher
	*/		*/

			/**
			* DOC: PRIME Buffer Sharing
			*
			* The following callback implementations are used for :ref:`sharing GEM buffer
			* objects between different devices via PRIME <prime_buffer_sharing>`.
			*/

	#include <drm/drmP.h>		#include <drm/drmP.h>

	#include "amdgpu.h"		#include "amdgpu.h"
	@@ -32,6 +40,14 @@

	static const struct dma_buf_ops amdgpu_dmabuf_ops;		static const struct dma_buf_ops amdgpu_dmabuf_ops;

			/**
			* amdgpu_gem_prime_get_sg_table - &drm_driver.gem_prime_get_sg_table
			* implementation
			* @obj: GEM buffer object
			*
			* Returns:
			* A scatter/gather table for the pinned pages of the buffer object's memory.
			*/
	struct sg_table amdgpu_gem_prime_get_sg_table(struct drm_gem_object obj)		struct sg_table amdgpu_gem_prime_get_sg_table(struct drm_gem_object obj)
	{		{
	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);		struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
	@@ -40,6 +56,15 @@ struct sg_table amdgpu_gem_prime_get_sg_table(struct drm_gem_object obj)
	return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages);		return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages);
	}		}

			/**
			* amdgpu_gem_prime_vmap - &dma_buf_ops.vmap implementation
			* @obj: GEM buffer object
			*
			* Sets up an in-kernel virtual mapping of the buffer object's memory.
			*
			* Returns:
			* The virtual address of the mapping or an error pointer.
			*/
	void amdgpu_gem_prime_vmap(struct drm_gem_object obj)		void amdgpu_gem_prime_vmap(struct drm_gem_object obj)
	{		{
	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);		struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
	@@ -53,6 +78,13 @@ void amdgpu_gem_prime_vmap(struct drm_gem_object obj)
	return bo->dma_buf_vmap.virtual;		return bo->dma_buf_vmap.virtual;
	}		}

			/**
			* amdgpu_gem_prime_vunmap - &dma_buf_ops.vunmap implementation
			* @obj: GEM buffer object
			* @vaddr: virtual address (unused)
			*
			* Tears down the in-kernel virtual mapping of the buffer object's memory.
			*/
	void amdgpu_gem_prime_vunmap(struct drm_gem_object obj, void vaddr)		void amdgpu_gem_prime_vunmap(struct drm_gem_object obj, void vaddr)
	{		{
	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);		struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
	@@ -60,6 +92,17 @@ void amdgpu_gem_prime_vunmap(struct drm_gem_object obj, void vaddr)
	ttm_bo_kunmap(&bo->dma_buf_vmap);		ttm_bo_kunmap(&bo->dma_buf_vmap);
	}		}

			/**
			* amdgpu_gem_prime_mmap - &drm_driver.gem_prime_mmap implementation
			* @obj: GEM buffer object
			* @vma: virtual memory area
			*
			* Sets up a userspace mapping of the buffer object's memory in the given
			* virtual memory area.
			*
			* Returns:
			* 0 on success or negative error code.
			*/
	int amdgpu_gem_prime_mmap(struct drm_gem_object obj, struct vm_area_struct vma)		int amdgpu_gem_prime_mmap(struct drm_gem_object obj, struct vm_area_struct vma)
	{		{
	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);		struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
	@@ -94,6 +137,19 @@ int amdgpu_gem_prime_mmap(struct drm_gem_object obj, struct vm_area_struct vma
	return ret;		return ret;
	}		}

			/**
			* amdgpu_gem_prime_import_sg_table - &drm_driver.gem_prime_import_sg_table
			* implementation
			* @dev: DRM device
			* @attach: DMA-buf attachment
			* @sg: Scatter/gather table
			*
			* Import shared DMA buffer memory exported by another device.
			*
			* Returns:
			* A new GEM buffer object of the given DRM device, representing the memory
			* described by the given DMA-buf attachment and scatter/gather table.
			*/
	struct drm_gem_object *		struct drm_gem_object *
	amdgpu_gem_prime_import_sg_table(struct drm_device *dev,		amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
	struct dma_buf_attachment *attach,		struct dma_buf_attachment *attach,
	@@ -132,6 +188,19 @@ amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
	return ERR_PTR(ret);		return ERR_PTR(ret);
	}		}

			/**
			* amdgpu_gem_map_attach - &dma_buf_ops.attach implementation
			* @dma_buf: shared DMA buffer
			* @target_dev: target device
			* @attach: DMA-buf attachment
			*
			* Makes sure that the shared DMA buffer can be accessed by the target device.
			* For now, simply pins it to the GTT domain, where it should be accessible by
			* all DMA devices.
			*
			* Returns:
			* 0 on success or negative error code.
			*/
	static int amdgpu_gem_map_attach(struct dma_buf *dma_buf,		static int amdgpu_gem_map_attach(struct dma_buf *dma_buf,
	struct device *target_dev,		struct device *target_dev,
	struct dma_buf_attachment *attach)		struct dma_buf_attachment *attach)
	@@ -181,6 +250,14 @@ static int amdgpu_gem_map_attach(struct dma_buf *dma_buf,
	return r;		return r;
	}		}

			/**
			* amdgpu_gem_map_detach - &dma_buf_ops.detach implementation
			* @dma_buf: shared DMA buffer
			* @attach: DMA-buf attachment
			*
			* This is called when a shared DMA buffer no longer needs to be accessible by
			* the other device. For now, simply unpins the buffer from GTT.
			*/
	static void amdgpu_gem_map_detach(struct dma_buf *dma_buf,		static void amdgpu_gem_map_detach(struct dma_buf *dma_buf,
	struct dma_buf_attachment *attach)		struct dma_buf_attachment *attach)
	{		{
	@@ -202,6 +279,13 @@ static void amdgpu_gem_map_detach(struct dma_buf *dma_buf,
	drm_gem_map_detach(dma_buf, attach);		drm_gem_map_detach(dma_buf, attach);
	}		}

			/**
			* amdgpu_gem_prime_res_obj - &drm_driver.gem_prime_res_obj implementation
			* @obj: GEM buffer object
			*
			* Returns:
			* The buffer object's reservation object.
			*/
	struct reservation_object amdgpu_gem_prime_res_obj(struct drm_gem_object obj)		struct reservation_object amdgpu_gem_prime_res_obj(struct drm_gem_object obj)
	{		{
	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);		struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
	@@ -209,6 +293,18 @@ struct reservation_object amdgpu_gem_prime_res_obj(struct drm_gem_object obj)
	return bo->tbo.resv;		return bo->tbo.resv;
	}		}

			/**
			* amdgpu_gem_begin_cpu_access - &dma_buf_ops.begin_cpu_access implementation
			* @dma_buf: shared DMA buffer
			* @direction: direction of DMA transfer
			*
			* This is called before CPU access to the shared DMA buffer's memory. If it's
			* a read access, the buffer is moved to the GTT domain if possible, for optimal
			* CPU read performance.
			*
			* Returns:
			* 0 on success or negative error code.
			*/
	static int amdgpu_gem_begin_cpu_access(struct dma_buf *dma_buf,		static int amdgpu_gem_begin_cpu_access(struct dma_buf *dma_buf,
	enum dma_data_direction direction)		enum dma_data_direction direction)
	{		{
	@@ -253,6 +349,18 @@ static const struct dma_buf_ops amdgpu_dmabuf_ops = {
	.vunmap = drm_gem_dmabuf_vunmap,		.vunmap = drm_gem_dmabuf_vunmap,
	};		};

			/**
			* amdgpu_gem_prime_export - &drm_driver.gem_prime_export implementation
			* @dev: DRM device
			* @gobj: GEM buffer object
			* @flags: flags like DRM_CLOEXEC and DRM_RDWR
			*
			* The main work is done by the &drm_gem_prime_export helper, which in turn
			* uses &amdgpu_gem_prime_res_obj.
			*
			* Returns:
			* Shared DMA buffer representing the GEM buffer object from the given device.
			*/
	struct dma_buf amdgpu_gem_prime_export(struct drm_device dev,		struct dma_buf amdgpu_gem_prime_export(struct drm_device dev,
	struct drm_gem_object *gobj,		struct drm_gem_object *gobj,
	int flags)		int flags)
	@@ -273,6 +381,17 @@ struct dma_buf amdgpu_gem_prime_export(struct drm_device dev,
	return buf;		return buf;
	}		}

			/**
			* amdgpu_gem_prime_import - &drm_driver.gem_prime_import implementation
			* @dev: DRM device
			* @dma_buf: Shared DMA buffer
			*
			* The main work is done by the &drm_gem_prime_import helper, which in turn
			* uses &amdgpu_gem_prime_import_sg_table.
			*
			* Returns:
			* GEM buffer object representing the shared DMA buffer for the given device.
			*/
	struct drm_gem_object amdgpu_gem_prime_import(struct drm_device dev,		struct drm_gem_object amdgpu_gem_prime_import(struct drm_device dev,
	struct dma_buf *dma_buf)		struct dma_buf *dma_buf)
	{		{