path: root/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c

/*
 * Copyright 2011 (c) Oracle Corp.

 * 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.
 *
 * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
 */

/*
 * A simple DMA pool losely based on dmapool.c. It has certain advantages
 * over the DMA pools:
 * - Pool collects resently freed pages for reuse (and hooks up to
 *   the shrinker).
 * - Tracks currently in use pages
 * - Tracks whether the page is UC, WB or cached (and reverts to WB
 *   when freed).
 */

#define pr_fmt(fmt) "[TTM] " fmt

#include <linux/dma-mapping.h>
#include <linux/list.h>
#include <linux/seq_file.h> /* for seq_printf */
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/highmem.h>
#include <linux/mm_types.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/atomic.h>
#include <linux/device.h>
#include <linux/kthread.h>
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_page_alloc.h>
#include <drm/ttm/ttm_set_memory.h>

#define NUM_PAGES_TO_ALLOC		(PAGE_SIZE/sizeof(struct page *))
#define SMALL_ALLOCATION		4
#define FREE_ALL_PAGES			(~0U)
#define VADDR_FLAG_HUGE_POOL		1UL
#define VADDR_FLAG_UPDATED_COUNT	2UL

enum pool_type {
	IS_UNDEFINED	= 0,
	IS_WC		= 1 << 1,
	IS_UC		= 1 << 2,
	IS_CACHED	= 1 << 3,
	IS_DMA32	= 1 << 4,
	IS_HUGE		= 1 << 5
};

/*
 * The pool structure. There are up to nine pools:
 *  - generic (not restricted to DMA32):
 *      - write combined, uncached, cached.
 *  - dma32 (up to 2^32 - so up 4GB):
 *      - write combined, uncached, cached.
 *  - huge (not restricted to DMA32):
 *      - write combined, uncached, cached.
 * for each 'struct device'. The 'cached' is for pages that are actively used.
 * The other ones can be shrunk by the shrinker API if neccessary.
 * @pools: The 'struct device->dma_pools' link.
 * @type: Type of the pool
 * @lock: Protects the free_list from concurrnet access. Must be
 * used with irqsave/irqrestore variants because pool allocator maybe called
 * from delayed work.
 * @free_list: Pool of pages that are free to be used. No order requirements.
 * @dev: The device that is associated with these pools.
 * @size: Size used during DMA allocation.
 * @npages_free: Count of available pages for re-use.
 * @npages_in_use: Count of pages that are in use.
 * @nfrees: Stats when pool is shrinking.
 * @nrefills: Stats when the pool is grown.
 * @gfp_flags: Flags to pass for alloc_page.
 * @name: Name of the pool.
 * @dev_name: Name derieved from dev - similar to how dev_info works.
 *   Used during shutdown as the dev_info during release is unavailable.
 */
struct dma_pool {
	struct list_head pools; /* The 'struct device->dma_pools link */
	enum pool_type type;
	spinlock_t lock;
	struct list_head free_list;
	struct device *dev;
	unsigned size;
	unsigned npages_free;
	unsigned npages_in_use;
	unsigned long nfrees; /* Stats when shrunk. */
	unsigned long nrefills; /* Stats when grown. */
	gfp_t gfp_flags;
	char name[13]; /* "cached dma32" */
	char dev_name[64]; /* Constructed from dev */
};

/*
 * The accounting page keeping track of the allocated page along with
 * the DMA address.
 * @page_list: The link to the 'page_list' in 'struct dma_pool'.
 * @vaddr: The virtual address of the page and a flag if the page belongs to a
 * huge pool
 * @dma: The bus address of the page. If the page is not allocated
 *   via the DMA API, it will be -1.
 */
struct dma_page {
	struct list_head page_list;
	unsigned long vaddr;
	struct page *p;
	dma_addr_t dma;
};

/*
 * 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;
};

/*
 * Contains the list of all of the 'struct device' and their corresponding
 * DMA pools. Guarded by _mutex->lock.
 * @pools: The link to 'struct ttm_pool_manager->pools'
 * @dev: The 'struct device' associated with the 'pool'
 * @pool: The 'struct dma_pool' associated with the 'dev'
 */
struct device_pools {
	struct list_head pools;
	struct device *dev;
	struct dma_pool *pool;
};

/*
 * struct ttm_pool_manager - Holds memory pools for fast allocation
 *
 * @lock: Lock used when adding/removing from pools
 * @pools: List of 'struct device' and 'struct dma_pool' tuples.
 * @options: Limits for the pool.
 * @npools: Total amount of pools in existence.
 * @shrinker: The structure used by [un|]register_shrinker
 */
struct ttm_pool_manager {
	struct mutex		lock;
	struct list_head	pools;
	struct ttm_pool_opts	options;
	unsigned		npools;
	struct shrinker		mm_shrink;
	struct kobject		kobj;
};

static struct ttm_pool_manager *_manager;

static struct attribute ttm_page_pool_max = {
	.name = &