drm/amdgpu: Add documentation for PRIME related code (baca30fa) · Commits · github.com / kvm-riscv / linux

Documentation/gpu/amdgpu.rst

+14 −0

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

		The drm/amdgpu driver supports all AMD Radeon GPUs based on the Graphics Core
		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	Diff line number	Diff line
		@@ -23,6 +23,14 @@
		*
		* 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 "amdgpu.h"
		@@ -32,6 +40,14 @@

		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 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);
		}

		/**
		* 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)
		{
		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;
		}

		/**
		* 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)
		{
		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);
		}

		/**
		* 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)
		{
		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;
		}

		/**
		* 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 *
		amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
		struct dma_buf_attachment *attach,
		@@ -132,6 +188,19 @@ amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
		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,
		struct device *target_dev,
		struct dma_buf_attachment *attach)
		@@ -181,6 +250,14 @@ static int amdgpu_gem_map_attach(struct dma_buf *dma_buf,
		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,
		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);
		}

		/**
		* 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 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;
		}

		/**
		* 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,
		enum dma_data_direction direction)
		{
		@@ -253,6 +349,18 @@ static const struct dma_buf_ops amdgpu_dmabuf_ops = {
		.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 drm_gem_object *gobj,
		int flags)
		@@ -273,6 +381,17 @@ struct dma_buf amdgpu_gem_prime_export(struct drm_device dev,
		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 dma_buf *dma_buf)
		{