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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2016 Intel Corporation
*/
#include "i915_scatterlist.h"
#include "i915_ttm_buddy_manager.h"
#include <drm/drm_buddy.h>
#include <drm/drm_mm.h>
#include <linux/slab.h>
bool i915_sg_trim(struct sg_table *orig_st)
{
struct sg_table new_st;
struct scatterlist *sg, *new_sg;
unsigned int i;
if (orig_st->nents == orig_st->orig_nents)
return false;
if (sg_alloc_table(&new_st, orig_st->nents, GFP_KERNEL | __GFP_NOWARN))
return false;
new_sg = new_st.sgl;
for_each_sg(orig_st->sgl, sg, orig_st->nents, i) {
sg_set_page(new_sg, sg_page(sg), sg->length, 0);
sg_dma_address(new_sg) = sg_dma_address(sg);
sg_dma_len(new_sg) = sg_dma_len(sg);
new_sg = sg_next(new_sg);
}
GEM_BUG_ON(new_sg); /* Should walk exactly nents and hit the end */
sg_free_table(orig_st);
*orig_st = new_st;
return true;
}
static void i915_refct_sgt_release(struct kref *ref)
{
struct i915_refct_sgt *rsgt =
container_of(ref, typeof(*rsgt), kref);
sg_free_table(&rsgt->table);
kfree(rsgt);
}
static const struct i915_refct_sgt_ops rsgt_ops = {
.release = i915_refct_sgt_release
};
/**
* i915_refct_sgt_init - Initialize a struct i915_refct_sgt with default ops
* @rsgt: The struct i915_refct_sgt to initialize.
* size: The size of the underlying memory buffer.
*/
void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size)
{
__i915_refct_sgt_init(rsgt, size, &rsgt_ops);
}
/**
* i915_rsgt_from_mm_node - Create a refcounted sg_table from a struct
* drm_mm_node
* @node: The drm_mm_node.
* @region_start: An offset to add to the dma addresses of the sg list.
*
* Create a struct sg_table, initializing it from a struct drm_mm_node,
* taking a maximum segment length into account, splitting into segments
* if necessary.
*
* Return: A pointer to a kmalloced struct i915_refct_sgt on success, negative
* error code cast to an error pointer on failure.
*/
struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
u64 region_start)
{
const u64 max_segment = SZ_1G; /* Do we have a limit on this? */
u64 segment_pages = max_segment >> PAGE_SHIFT;
u64 block_size, offset, prev_end;
struct i915_refct_sgt *rsgt;
struct sg_table *st;
struct scatterlist *sg;
rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL);
if (!rsgt)
return ERR_PTR(-ENOMEM);
i915_refct_sgt_init(rsgt, node->size << PAGE_SHIFT);
st = &rsgt->table;
if (sg_alloc_table(st, DIV_ROUND_UP(node->size, segment_pages),
GFP_KERNEL)) {
i915_refct_sgt_put(rsgt);
return ERR_PTR(-ENOMEM);
}
sg = st->sgl;
st->nents = 0;
prev_end = (resource_size_t)-1;
block_size = node->size << PAGE_SHIFT;
offset = node->start << PAGE_SHIFT;
while (block_size) {
u64 len;
if (offset != prev_end || sg->length >= max_segment) {
if (st->nents)
sg = __sg_next(sg);
sg_dma_address(sg) = region_start + offset;
sg_dma_len(sg) = 0;
sg->length = 0;
st->nents++;
}
len = min(block_size, max_segment - sg->length);
sg->length += len;
sg_dma_len(sg) += len;
offset += len;
block_size -= len;
prev_end = offset;
}
sg_mark_end(sg);
i915_sg_trim(st);
return rsgt;
}
/**
* i915_rsgt_from_buddy_resource - Create a refcounted sg_table from a struct
* i915_buddy_block list
* @res: The struct i915_ttm_buddy_resource.
* @region_start: An offset to add to the dma addresses of the sg list.
*
* Create a struct sg_table, initializing it from struct i915_buddy_block list,
* taking a maximum segment length into account, splitting into segments
* if necessary.
*
* Return: A pointer to a kmalloced struct i915_refct_sgts on success, negative
* error code cast to an error pointer on failure.
*/
struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
u64 region_start)
{
struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res);
const u64 size = res->num_pages << PAGE_SHIFT;
const u64 max_segment = rounddown(UINT_MAX, PAGE_SIZE);
struct drm_buddy *mm = bman_res->mm;
struct list_head *blocks = &bman_res->blocks;
struct drm_buddy_block *block;
struct i915_refct_sgt *rsgt;
struct scatterlist *sg;
struct sg_table *st;
resource_size_t prev_end;
GEM_BUG_ON(list_empty(blocks));
rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL);
if (!rsgt)
return ERR_PTR(-ENOMEM);
i915_refct_sgt_init(rsgt, size);
st = &rsgt->table;
if (sg_alloc_table(st, res->num_pages, GFP_KERNEL)) {
i915_refct_sgt_put(rsgt);
return ERR_PTR(-ENOMEM);
}
sg = st->sgl;
st->nents = 0;
prev_end = (resource_size_t)-1;
list_for_each_entry(block, blocks, link) {
u64 block_size, offset;
block_size = min_t(u64, size, drm_buddy_block_size(mm, block));
offset = drm_buddy_block_offset(block);
while (block_size) {
u64 len;
if (offset != prev_end || sg->length >= max_segment) {
if (st->nents)
sg = __sg_next(sg);
sg_dma_address(sg) = region_start + offset;
sg_dma_len(sg) = 0;
sg->length = 0;
st->nents++;
}
len = min(block_size, max_segment - sg->length);
sg->length += len;
sg_dma_len(sg) += len;
offset += len;
block_size -= len;
prev_end = offset;
}
}
sg_mark_end(sg);
i915_sg_trim(st);
return rsgt;
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/scatterlist.c"
#endif
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