/*
* 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>
* Jerome Glisse <jglisse@redhat.com>
* Pauli Nieminen <suokkos@gmail.com>
*/
/* simple list based uncached page pool
* - Pool collects resently freed pages for reuse
* - Use page->lru to keep a free list
* - doesn't track currently in use pages
*/
#define pr_fmt(fmt) "[TTM] " fmt
#include <linux/list.h>
#include <linux/spinlock.h>
//#include <linux/highmem.h>
//#include <linux/mm_types.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/seq_file.h> /* for seq_printf */
#include <linux/slab.h>
//#include <linux/dma-mapping.h>
#include <linux/atomic.h>
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_page_alloc.h>
#ifdef TTM_HAS_AGP
#include <asm/agp.h>
#endif
#define NUM_PAGES_TO_ALLOC (PAGE_SIZE/sizeof(struct page *))
#define SMALL_ALLOCATION 16
#define FREE_ALL_PAGES (~0U)
/* times are in msecs */
#define PAGE_FREE_INTERVAL 1000
/**
* struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
*
* @lock: Protects the shared pool from concurrnet access. Must be used with
* irqsave/irqrestore variants because pool allocator maybe called from
* delayed work.
* @fill_lock: Prevent concurrent calls to fill.
* @list: Pool of free uc/wc pages for fast reuse.
* @gfp_flags: Flags to pass for alloc_page.
* @npages: Number of pages in pool.
*/
struct ttm_page_pool {
spinlock_t lock;
bool fill_lock;
struct list_head list;
gfp_t gfp_flags;
unsigned npages;
char *name;
unsigned long nfrees;
unsigned long nrefills;
};
/**
* Limits for the pool. They are handled without locks because only place where
* they may change is in sysfs store. They won't have immediate effect anyway
* so forcing serialization to access them is pointless.
*/
struct ttm_pool_opts {
unsigned alloc_size;
unsigned max_size;
unsigned small;
};
#define NUM_POOLS 4
/**
* struct ttm_pool_manager - Holds memory pools for fst allocation
*
* Manager is read only object for pool code so it doesn't need locking.
*
* @free_interval: minimum number of jiffies between freeing pages from pool.
* @page_alloc_inited: reference counting for pool allocation.
* @work: Work that is used to shrink the pool. Work is only run when there is
* some pages to free.
* @small_allocation: Limit in number of pages what is small allocation.
*
* @pools: All pool objects in use.
**/
struct ttm_pool_manager {
struct kobject kobj;
struct ttm_pool_opts options;
union {
struct ttm_page_pool pools[NUM_POOLS];
struct {
struct ttm_page_pool wc_pool;
struct ttm_page_pool uc_pool;
struct ttm_page_pool wc_pool_dma32;
struct ttm_page_pool uc_pool_dma32;
} ;
};
};
static struct ttm_pool_manager *_manager;
/**
* Select the right pool or requested caching state and ttm flags. */
static struct ttm_page_pool *ttm_get_pool(int flags,
enum ttm_caching_state cstate)
{
int pool_index;
if (cstate == tt_cached)
return NULL;
if (cstate == tt_wc)
pool_index = 0x0;
else
pool_index = 0x1;
if (flags & TTM_PAGE_FLAG_DMA32)
pool_index |= 0x2;
return &_manager->pools[pool_index];
}
/* set memory back to wb and free the pages. */
static void ttm_pages_put(struct page *pages[], unsigned npages)
{
unsigned i;
for (i = 0; i < npages; ++i)
__free_page(pages[i]);
}
static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
unsigned freed_pages)
{
pool->npages -= freed_pages;
pool->nfrees += freed_pages;
}
/* Put all pages in pages list to correct pool to wait for reuse */
static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
enum ttm_caching_state cstate)
{
unsigned long irq_flags;
struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
unsigned i;
if (1) {
/* No pool for this memory type so free the pages */
for (i = 0; i < npages; i++) {
if (pages[i]) {
__free_page(pages[i]);
pages[i] = NULL;
}
}
return;
}
}
/*
* On success pages list will hold count number of correctly
* cached pages.
*/
static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
enum ttm_caching_state cstate)
{
struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
struct list_head plist;
struct page *p = NULL;
gfp_t gfp_flags = 0;
unsigned count;
int r;
/* No pool for cached pages */
if (1) {
for (r = 0; r < npages; ++r) {
p = alloc_page(gfp_flags);
if (!p) {
return -ENOMEM;
}
pages[r] = p;
}
return 0;
}
return 0;
}
static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, gfp_t flags,
char *name)
{
spin_lock_init(&pool->lock);
pool->fill_lock = false;
INIT_LIST_HEAD(&pool->list);
pool->npages = pool->nfrees = 0;
pool->gfp_flags = flags;
pool->name = name;
}
int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
{
int ret;
WARN_ON(_manager);
_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
_manager->options.max_size = max_pages;
_manager->options.small = SMALL_ALLOCATION;
_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
return 0;
}
void ttm_page_alloc_fini(void)
{
int i;
_manager = NULL;
}
int ttm_pool_populate(struct ttm_tt *ttm)
{
struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
unsigned i;
int ret;
if (ttm->state != tt_unpopulated)
return 0;
for (i = 0; i < ttm->num_pages; ++i) {
ret = ttm_get_pages(&ttm->pages[i], 1,
ttm->page_flags,
ttm->caching_state);
if (ret != 0) {
ttm_pool_unpopulate(ttm);
return -ENOMEM;
}
}
ttm->state = tt_unbound;
return 0;
}
EXPORT_SYMBOL(ttm_pool_populate);
void ttm_pool_unpopulate(struct ttm_tt *ttm)
{
unsigned i;
for (i = 0; i < ttm->num_pages; ++i) {
if (ttm->pages[i]) {
ttm_put_pages(&ttm->pages[i], 1,
ttm->page_flags,
ttm->caching_state);
}
}
ttm->state = tt_unpopulated;
}
EXPORT_SYMBOL(ttm_pool_unpopulate);