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From 4bd7a3507a307848df7842f599c8295d45575948 Mon Sep 17 00:00:00 2001
From: Michel Daenzer <michel.daenzer@amd.com>
Date: Tue, 29 May 2018 18:33:41 +0200
Subject: [PATCH 4586/5725] drm/amdgpu: Add documentation for PRIME related
code
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Kalyan Alle <kalyan.alle@amd.com>
Conflicts:
drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
Change-Id: I5bd9e7536250c9a1e9f914b87443c3b63aa2988f
---
drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c | 119 ++++++++++++++++++++++++++++++
1 file changed, 119 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
index 63d5a01..5472366 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
@@ -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"
@@ -30,6 +38,14 @@
#include <drm/amdgpu_drm.h>
#include <linux/dma-buf.h>
+/**
+ * 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);
@@ -38,6 +54,15 @@ 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);
@@ -51,6 +76,13 @@ 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);
@@ -58,6 +90,17 @@ 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);
@@ -92,6 +135,19 @@ 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,
@@ -135,6 +191,19 @@ amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 17, 0) || !defined(BUILD_AS_DKMS)
+/**
+ * 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)
@@ -184,6 +253,14 @@ 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)
{
@@ -205,6 +282,13 @@ static void amdgpu_gem_map_detach(struct dma_buf *dma_buf,
}
#endif
+/**
+ * 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);
@@ -213,6 +297,18 @@ struct reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *obj)
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 17, 0) || !defined(BUILD_AS_DKMS)
+/**
+ * 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)
{
@@ -258,6 +354,18 @@ const struct dma_buf_ops amdgpu_dmabuf_ops = {
};
#endif
+/**
+ * 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)
@@ -280,6 +388,17 @@ struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 17, 0) || !defined(BUILD_AS_DKMS)
+/**
+ * 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)
{
--
2.7.4
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