drm/linux-core/drm_uncached.c

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/*
* Copyright (c) Red Hat Inc.
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sub license,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Authors: Dave Airlie <airlied@redhat.com>
*/
/* simple list based uncached page allocator
* - Add chunks of 1MB to the allocator at a time.
* - Use page->lru to keep a free list
* - doesn't track currently in use pages
*
* TODO: Add shrinker support
*/
#include "drmP.h"
#include <asm/agp.h>
static struct list_head uncached_free_list;
static struct mutex uncached_mutex;
static int uncached_inited;
static int total_uncached_pages;
/* add 1MB at a time */
#define NUM_PAGES_TO_ADD 256
static void drm_uncached_page_put(struct page *page)
{
unmap_page_from_agp(page);
put_page(page);
__free_page(page);
}
int drm_uncached_add_pages_locked(int num_pages)
{
struct page *page;
int i;
DRM_DEBUG("adding uncached memory %ld\n", num_pages * PAGE_SIZE);
for (i = 0; i < num_pages; i++) {
page = alloc_page(GFP_KERNEL | __GFP_ZERO | GFP_DMA32);
if (!page) {
DRM_ERROR("unable to get page %d\n", i);
return i;
}
get_page(page);
#ifdef CONFIG_X86
set_memory_wc((unsigned long)page_address(page), 1);
#else
map_page_into_agp(page);
#endif
list_add(&page->lru, &uncached_free_list);
total_uncached_pages++;
}
return i;
}
struct page *drm_get_uncached_page(void)
{
struct page *page = NULL;
int ret;
mutex_lock(&uncached_mutex);
if (list_empty(&uncached_free_list)) {
ret = drm_uncached_add_pages_locked(NUM_PAGES_TO_ADD);
if (ret == 0)
return NULL;
}
page = list_first_entry(&uncached_free_list, struct page, lru);
list_del(&page->lru);
mutex_unlock(&uncached_mutex);
return page;
}
void drm_put_uncached_page(struct page *page)
{
mutex_lock(&uncached_mutex);
list_add(&page->lru, &uncached_free_list);
mutex_unlock(&uncached_mutex);
}
void drm_uncached_release_all_pages(void)
{
struct page *page, *tmp;
list_for_each_entry_safe(page, tmp, &uncached_free_list, lru) {
list_del(&page->lru);
drm_uncached_page_put(page);
}
}
int drm_uncached_init(void)
{
if (uncached_inited)
return 0;
INIT_LIST_HEAD(&uncached_free_list);
mutex_init(&uncached_mutex);
uncached_inited = 1;
return 0;
}
void drm_uncached_fini(void)
{
if (!uncached_inited)
return;
uncached_inited = 0;
drm_uncached_release_all_pages();
}