blob: 4dea2a0dbd336f9146e5cd8c5c582221ac53d512 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* DMA Pool allocator
*
* Copyright 2001 David Brownell
* Copyright 2007 Intel Corporation
* Author: Matthew Wilcox <willy@linux.intel.com>
*
* This allocator returns small blocks of a given size which are DMA-able by
* the given device. It uses the dma_alloc_coherent page allocator to get
* new pages, then splits them up into blocks of the required size.
* Many older drivers still have their own code to do this.
*
* The current design of this allocator is fairly simple. The pool is
* represented by the 'struct dma_pool' which keeps a doubly-linked list of
* allocated pages. Each page in the page_list is split into blocks of at
* least 'size' bytes. Free blocks are tracked in an unsorted singly-linked
* list of free blocks within the page. Used blocks aren't tracked, but we
* keep a count of how many are currently allocated from each page.
*/
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/poison.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/wait.h>
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
#define DMAPOOL_DEBUG 1
#endif
struct dma_pool { /* the pool */
struct list_head page_list;
spinlock_t lock;
struct device *dev;
unsigned int size;
unsigned int allocation;
unsigned int boundary;
char name[32];
struct list_head pools;
};
struct dma_page { /* cacheable header for 'allocation' bytes */
struct list_head page_list;
void *vaddr;
dma_addr_t dma;
unsigned int in_use;
unsigned int offset;
};
static DEFINE_MUTEX(pools_lock);
static DEFINE_MUTEX(pools_reg_lock);
static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf)
{
int size;
struct dma_page *page;
struct dma_pool *pool;
size = sysfs_emit(buf, "poolinfo - 0.1\n");
mutex_lock(&pools_lock);
list_for_each_entry(pool, &dev->dma_pools, pools) {
unsigned pages = 0;
size_t blocks = 0;
spin_lock_irq(&pool->lock);
list_for_each_entry(page, &pool->page_list, page_list) {
pages++;
blocks += page->in_use;
}
spin_unlock_irq(&pool->lock);
/* per-pool info, no real statistics yet */
size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2u\n",
pool->name, blocks,
(size_t) pages *
(pool->allocation / pool->size),
pool->size, pages);
}
mutex_unlock(&pools_lock);
return size;
}
static DEVICE_ATTR_RO(pools);
#ifdef DMAPOOL_DEBUG
static void pool_check_block(struct dma_pool *pool, void *retval,
unsigned int offset, gfp_t mem_flags)
{
int i;
u8 *data = retval;
/* page->offset is stored in first 4 bytes */
for (i = sizeof(offset); i < pool->size; i++) {
if (data[i] == POOL_POISON_FREED)
continue;
dev_err(pool->dev, "%s %s, %p (corrupted)\n",
__func__, pool->name, retval);
/*
* Dump the first 4 bytes even if they are not
* POOL_POISON_FREED
*/
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
data, pool->size, 1);
break;
}
if (!want_init_on_alloc(mem_flags))
memset(retval, POOL_POISON_ALLOCATED, pool->size);
}
static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
void *vaddr, dma_addr_t dma)
{
unsigned int offset = vaddr - page->vaddr;
unsigned int chain = page->offset;
if ((dma - page->dma) != offset) {
dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n",
__func__, pool->name, vaddr, &dma);
return true;
}
while (chain < pool->allocation) {
if (chain != offset) {
chain = *(int *)(page->vaddr + chain);
continue;
}
dev_err(pool->dev, "%s %s, dma %pad already free\n",
__func__, pool->name, &dma);
return true;
}
memset(vaddr, POOL_POISON_FREED, pool->size);
return false;
}
static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
{
memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
}
#else
static void pool_check_block(struct dma_pool *pool, void *retval,
unsigned int offset, gfp_t mem_flags)
{
}
static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
void *vaddr, dma_addr_t dma)
{
return false;
}
static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
{
}
#endif
/**
* dma_pool_create - Creates a pool of consistent memory blocks, for dma.
* @name: name of pool, for diagnostics
* @dev: device that will be doing the DMA
* @size: size of the blocks in this pool.
* @align: alignment requirement for blocks; must be a power of two
* @boundary: returned blocks won't cross this power of two boundary
* Context: not in_interrupt()
*
* Given one of these pools, dma_pool_alloc()
* may be used to allocate memory. Such memory will all have "consistent"
* DMA mappings, accessible by the device and its driver without using
* cache flushing primitives. The actual size of blocks allocated may be
* larger than requested because of alignment.
*
* If @boundary is nonzero, objects returned from dma_pool_alloc() won't
* cross that size boundary. This is useful for devices which have
* addressing restrictions on individual DMA transfers, such as not crossing
* boundaries of 4KBytes.
*
* Return: a dma allocation pool with the requested characteristics, or
* %NULL if one can't be created.
*/
struct dma_pool *dma_pool_create(const char *name, struct device *dev,
size_t size, size_t align, size_t boundary)
{
struct dma_pool *retval;
size_t allocation;
bool empty = false;
if (!dev)
return NULL;
if (align == 0)
align = 1;
else if (align & (align - 1))
return NULL;
if (size == 0 || size > INT_MAX)
return NULL;
else if (size < 4)
size = 4;
size = ALIGN(size, align);
allocation = max_t(size_t, size, PAGE_SIZE);
if (!boundary)
boundary = allocation;
else if ((boundary < size) || (boundary & (boundary - 1)))
return NULL;
boundary = min(boundary, allocation);
retval = kmalloc(sizeof(*retval), GFP_KERNEL);
if (!retval)
return retval;
strscpy(retval->name, name, sizeof(retval->name));
retval->dev = dev;
INIT_LIST_HEAD(&retval->page_list);
spin_lock_init(&retval->lock);
retval->size = size;
retval->boundary = boundary;
retval->allocation = allocation;
INIT_LIST_HEAD(&retval->pools);
/*
* pools_lock ensures that the ->dma_pools list does not get corrupted.
* pools_reg_lock ensures that there is not a race between
* dma_pool_create() and dma_pool_destroy() or within dma_pool_create()
* when the first invocation of dma_pool_create() failed on
* device_create_file() and the second assumes that it has been done (I
* know it is a short window).
*/
mutex_lock(&pools_reg_lock);
mutex_lock(&pools_lock);
if (list_empty(&dev->dma_pools))
empty = true;
list_add(&retval->pools, &dev->dma_pools);
mutex_unlock(&pools_lock);
if (empty) {
int err;
err = device_create_file(dev, &dev_attr_pools);
if (err) {
mutex_lock(&pools_lock);
list_del(&retval->pools);
mutex_unlock(&pools_lock);
mutex_unlock(&pools_reg_lock);
kfree(retval);
return NULL;
}
}
mutex_unlock(&pools_reg_lock);
return retval;
}
EXPORT_SYMBOL(dma_pool_create);
static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
{
unsigned int offset = 0;
unsigned int next_boundary = pool->boundary;
pool_init_page(pool, page);
page->in_use = 0;
page->offset = 0;
do {
unsigned int next = offset + pool->size;
if (unlikely((next + pool->size) >= next_boundary)) {
next = next_boundary;
next_boundary += pool->boundary;
}
*(int *)(page->vaddr + offset) = next;
offset = next;
} while (offset < pool->allocation);
}
static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
{
struct dma_page *page;
page = kmalloc(sizeof(*page), mem_flags);
if (!page)
return NULL;
page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
&page->dma, mem_flags);
if (!page->vaddr) {
kfree(page);
return NULL;
}
pool_initialise_page(pool, page);
return page;
}
static inline bool is_page_busy(struct dma_page *page)
{
return page->in_use != 0;
}
/**
* dma_pool_destroy - destroys a pool of dma memory blocks.
* @pool: dma pool that will be destroyed
* Context: !in_interrupt()
*
* Caller guarantees that no more memory from the pool is in use,
* and that nothing will try to use the pool after this call.
*/
void dma_pool_destroy(struct dma_pool *pool)
{
struct dma_page *page, *tmp;
bool empty = false;
if (unlikely(!pool))
return;
mutex_lock(&pools_reg_lock);
mutex_lock(&pools_lock);
list_del(&pool->pools);
if (list_empty(&pool->dev->dma_pools))
empty = true;
mutex_unlock(&pools_lock);
if (empty)
device_remove_file(pool->dev, &dev_attr_pools);
mutex_unlock(&pools_reg_lock);
list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
if (!is_page_busy(page))
dma_free_coherent(pool->dev, pool->allocation,
page->vaddr, page->dma);
else
dev_err(pool->dev, "%s %s, %p busy\n", __func__,
pool->name, page->vaddr);
list_del(&page->page_list);
kfree(page);
}
kfree(pool);
}
EXPORT_SYMBOL(dma_pool_destroy);
/**
* dma_pool_alloc - get a block of consistent memory
* @pool: dma pool that will produce the block
* @mem_flags: GFP_* bitmask
* @handle: pointer to dma address of block
*
* Return: the kernel virtual address of a currently unused block,
* and reports its dma address through the handle.
* If such a memory block can't be allocated, %NULL is returned.
*/
void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
dma_addr_t *handle)
{
unsigned long flags;
struct dma_page *page;
unsigned int offset;
void *retval;
might_alloc(mem_flags);
spin_lock_irqsave(&pool->lock, flags);
list_for_each_entry(page, &pool->page_list, page_list) {
if (page->offset < pool->allocation)
goto ready;
}
/* pool_alloc_page() might sleep, so temporarily drop &pool->lock */
spin_unlock_irqrestore(&pool->lock, flags);
page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
if (!page)
return NULL;
spin_lock_irqsave(&pool->lock, flags);
list_add(&page->page_list, &pool->page_list);
ready:
page->in_use++;
offset = page->offset;
page->offset = *(int *)(page->vaddr + offset);
retval = offset + page->vaddr;
*handle = offset + page->dma;
pool_check_block(pool, retval, offset, mem_flags);
spin_unlock_irqrestore(&pool->lock, flags);
if (want_init_on_alloc(mem_flags))
memset(retval, 0, pool->size);
return retval;
}
EXPORT_SYMBOL(dma_pool_alloc);
static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
{
struct dma_page *page;
list_for_each_entry(page, &pool->page_list, page_list) {
if (dma < page->dma)
continue;
if ((dma - page->dma) < pool->allocation)
return page;
}
return NULL;
}
/**
* dma_pool_free - put block back into dma pool
* @pool: the dma pool holding the block
* @vaddr: virtual address of block
* @dma: dma address of block
*
* Caller promises neither device nor driver will again touch this block
* unless it is first re-allocated.
*/
void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
{
struct dma_page *page;
unsigned long flags;
spin_lock_irqsave(&pool->lock, flags);
page = pool_find_page(pool, dma);
if (!page) {
spin_unlock_irqrestore(&pool->lock, flags);
dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n",
__func__, pool->name, vaddr, &dma);
return;
}
if (want_init_on_free())
memset(vaddr, 0, pool->size);
if (pool_page_err(pool, page, vaddr, dma)) {
spin_unlock_irqrestore(&pool->lock, flags);
return;
}
page->in_use--;
*(int *)vaddr = page->offset;
page->offset = vaddr - page->vaddr;
/*
* Resist a temptation to do
* if (!is_page_busy(page)) pool_free_page(pool, page);
* Better have a few empty pages hang around.
*/
spin_unlock_irqrestore(&pool->lock, flags);
}
EXPORT_SYMBOL(dma_pool_free);
/*
* Managed DMA pool
*/
static void dmam_pool_release(struct device *dev, void *res)
{
struct dma_pool *pool = *(struct dma_pool **)res;
dma_pool_destroy(pool);
}
static int dmam_pool_match(struct device *dev, void *res, void *match_data)
{
return *(struct dma_pool **)res == match_data;
}
/**
* dmam_pool_create - Managed dma_pool_create()
* @name: name of pool, for diagnostics
* @dev: device that will be doing the DMA
* @size: size of the blocks in this pool.
* @align: alignment requirement for blocks; must be a power of two
* @allocation: returned blocks won't cross this boundary (or zero)
*
* Managed dma_pool_create(). DMA pool created with this function is
* automatically destroyed on driver detach.
*
* Return: a managed dma allocation pool with the requested
* characteristics, or %NULL if one can't be created.
*/
struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
size_t size, size_t align, size_t allocation)
{
struct dma_pool **ptr, *pool;
ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return NULL;
pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
if (pool)
devres_add(dev, ptr);
else
devres_free(ptr);
return pool;
}
EXPORT_SYMBOL(dmam_pool_create);
/**
* dmam_pool_destroy - Managed dma_pool_destroy()
* @pool: dma pool that will be destroyed
*
* Managed dma_pool_destroy().
*/
void dmam_pool_destroy(struct dma_pool *pool)
{
struct device *dev = pool->dev;
WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool));
}
EXPORT_SYMBOL(dmam_pool_destroy);