linux/drivers/gpu/drm/i915/i915_scatterlist.c
Thomas Hellström d148738923 drm/i915/ttm Initialize the ttm device and memory managers
Temporarily remove the buddy allocator and related selftests
and hook up the TTM range manager for i915 regions.

Also modify the mock region selftests somewhat to account for a
fragmenting manager.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602083818.241793-2-thomas.hellstrom@linux.intel.com
2021-06-02 13:21:24 +01:00

110 lines
2.4 KiB
C

/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2016 Intel Corporation
*/
#include "i915_scatterlist.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;
}
/**
* i915_sg_from_mm_node - Create an 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 sg_table on success, negative
* error code cast to an error pointer on failure.
*/
struct sg_table *i915_sg_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 sg_table *st;
struct scatterlist *sg;
st = kmalloc(sizeof(*st), GFP_KERNEL);
if (!st)
return ERR_PTR(-ENOMEM);
if (sg_alloc_table(st, DIV_ROUND_UP(node->size, segment_pages),
GFP_KERNEL)) {
kfree(st);
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 st;
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/scatterlist.c"
#endif