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/*
NOTE:
this code was lifted straight out of drivers/pci/pci.c;
when compiling for the Intel StrongARM SA-1110/SA-1111 the
usb-ohci.c driver needs these routines even when the architecture
has no pci bus...
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/bitops.h>
#include <asm/page.h>
#include "pcipool.h"
/*
* Pool allocator ... wraps the pci_alloc_consistent page allocator, so
* small blocks are easily used by drivers for bus mastering controllers.
* This should probably be sharing the guts of the slab allocator.
*/
struct pci_pool { /* the pool */
struct list_head page_list;
spinlock_t lock;
size_t blocks_per_page;
size_t size;
int flags;
struct pci_dev *dev;
size_t allocation;
char name [32];
wait_queue_head_t waitq;
};
struct pci_page { /* cacheable header for 'allocation' bytes */
struct list_head page_list;
void *vaddr;
dma_addr_t dma;
unsigned long bitmap [0];
};
#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
#define POOL_POISON_BYTE 0xa7
// #define CONFIG_PCIPOOL_DEBUG
/**
* pci_pool_create - Creates a pool of pci consistent memory blocks, for dma.
* @name: name of pool, for diagnostics
* @pdev: pci 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)
* @flags: SLAB_* flags (not all are supported).
*
* Returns a pci allocation pool with the requested characteristics, or
* null if one can't be created. Given one of these pools, pci_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 allocation is nonzero, objects returned from pci_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.
*/
struct pci_pool *
pci_pool_create (const char *name, struct pci_dev *pdev,
size_t size, size_t align, size_t allocation, int flags)
{
struct pci_pool *retval;
if (align == 0)
align = 1;
if (size == 0)
return 0;
else if (size < align)
size = align;
else if ((size % align) != 0) {
size += align + 1;
size &= ~(align - 1);
}
if (allocation == 0) {
if (PAGE_SIZE < size)
allocation = size;
else
allocation = PAGE_SIZE;
// FIXME: round up for less fragmentation
} else if (allocation < size)
return 0;
if (!(retval = kmalloc (sizeof *retval, flags)))
return retval;
#ifdef CONFIG_PCIPOOL_DEBUG
flags |= SLAB_POISON;
#endif
strncpy (retval->name, name, sizeof retval->name);
retval->name [sizeof retval->name - 1] = 0;
retval->dev = pdev;
INIT_LIST_HEAD (&retval->page_list);
spin_lock_init (&retval->lock);
retval->size = size;
retval->flags = flags;
retval->allocation = allocation;
retval->blocks_per_page = allocation / size;
init_waitqueue_head (&retval->waitq);
#ifdef CONFIG_PCIPOOL_DEBUG
printk (KERN_DEBUG "pcipool create %s/%s size %d, %d/page (%d alloc)\n",
pdev ? pdev->slot_name : NULL, retval->name, size,
retval->blocks_per_page, allocation);
#endif
return retval;
}
static struct pci_page *
pool_alloc_page (struct pci_pool *pool, int mem_flags)
{
struct pci_page *page;
int mapsize;
mapsize = pool->blocks_per_page;
mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
mapsize *= sizeof (long);
page = (struct pci_page *) kmalloc (mapsize + sizeof *page, mem_flags);
if (!page)
return 0;
page->vaddr = pci_alloc_consistent (pool->dev,
pool->allocation, &page->dma);
if (page->vaddr) {
memset (page->bitmap, 0xff, mapsize); // bit set == free
if (pool->flags & SLAB_POISON)
memset (page->vaddr, POOL_POISON_BYTE, pool->allocation);
list_add (&page->page_list, &pool->page_list);
} else {
kfree (page);
page = 0;
}
return page;
}
static inline int
is_page_busy (int blocks, unsigned long *bitmap)
{
while (blocks > 0) {
if (*bitmap++ != ~0UL)
return 1;
blocks -= BITS_PER_LONG;
}
return 0;
}
static void
pool_free_page (struct pci_pool *pool, struct pci_page *page)
{
dma_addr_t dma = page->dma;
if (pool->flags & SLAB_POISON)
memset (page->vaddr, POOL_POISON_BYTE, pool->allocation);
pci_free_consistent (pool->dev, pool->allocation, page->vaddr, dma);
list_del (&page->page_list);
kfree (page);
}
/**
* pci_pool_destroy - destroys a pool of pci memory blocks.
* @pool: pci pool that will be destroyed
*
* 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
pci_pool_destroy (struct pci_pool *pool)
{
unsigned long flags;
#ifdef CONFIG_PCIPOOL_DEBUG
printk (KERN_DEBUG "pcipool destroy %s/%s\n",
pool->dev ? pool->dev->slot_name : NULL,
pool->name);
#endif
spin_lock_irqsave (&pool->lock, flags);
while (!list_empty (&pool->page_list)) {
struct pci_page *page;
page = list_entry (pool->page_list.next,
struct pci_page, page_list);
if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
printk (KERN_ERR "pci_pool_destroy %s/%s, %p busy\n",
pool->dev ? pool->dev->slot_name : NULL,
pool->name, page->vaddr);
/* leak the still-in-use consistent memory */
list_del (&page->page_list);
kfree (page);
} else
pool_free_page (pool, page);
}
spin_unlock_irqrestore (&pool->lock, flags);
kfree (pool);
}
/**
* pci_pool_alloc - get a block of consistent memory
* @pool: pci pool that will produce the block
* @mem_flags: SLAB_KERNEL or SLAB_ATOMIC
* @handle: pointer to dma address of block
*
* This returns 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 *
pci_pool_alloc (struct pci_pool *pool, int mem_flags, dma_addr_t *handle)
{
unsigned long flags;
struct list_head *entry;
struct pci_page *page;
int map, block;
size_t offset;
void *retval;
restart:
spin_lock_irqsave (&pool->lock, flags);
list_for_each (entry, &pool->page_list) {
int i;
page = list_entry (entry, struct pci_page, page_list);
/* only cachable accesses here ... */
for (map = 0, i = 0;
i < pool->blocks_per_page;
i += BITS_PER_LONG, map++) {
if (page->bitmap [map] == 0)
continue;
block = ffz (~ page->bitmap [map]);
if ((i + block) < pool->blocks_per_page) {
clear_bit (block, &page->bitmap [map]);
offset = (BITS_PER_LONG * map) + block;
offset *= pool->size;
goto ready;
}
}
}
if (!(page = pool_alloc_page (pool, mem_flags))) {
if (mem_flags == SLAB_KERNEL) {
DECLARE_WAITQUEUE (wait, current);
current->state = TASK_INTERRUPTIBLE;
add_wait_queue (&pool->waitq, &wait);
spin_unlock_irqrestore (&pool->lock, flags);
schedule_timeout (POOL_TIMEOUT_JIFFIES);
current->state = TASK_RUNNING;
remove_wait_queue (&pool->waitq, &wait);
goto restart;
}
retval = 0;
goto done;
}
clear_bit (0, &page->bitmap [0]);
offset = 0;
ready:
retval = offset + page->vaddr;
*handle = offset + page->dma;
done:
spin_unlock_irqrestore (&pool->lock, flags);
return retval;
}
static struct pci_page *
pool_find_page (struct pci_pool *pool, dma_addr_t dma)
{
unsigned long flags;
struct list_head *entry;
struct pci_page *page;
spin_lock_irqsave (&pool->lock, flags);
list_for_each (entry, &pool->page_list) {
page = list_entry (entry, struct pci_page, page_list);
if (dma < page->dma)
continue;
if (dma < (page->dma + pool->allocation))
goto done;
}
page = 0;
done:
spin_unlock_irqrestore (&pool->lock, flags);
return page;
}
/**
* pci_pool_free - put block back into pci pool
* @pool: the pci 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
pci_pool_free (struct pci_pool *pool, void *vaddr, dma_addr_t dma)
{
struct pci_page *page;
unsigned long flags;
int map, block;
if ((page = pool_find_page (pool, dma)) == 0) {
printk (KERN_ERR "pci_pool_free %s/%s, %p/%x (bad dma)\n",
pool->dev ? pool->dev->slot_name : NULL,
pool->name, vaddr, dma);
return;
}
#ifdef CONFIG_PCIPOOL_DEBUG
if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
printk (KERN_ERR "pci_pool_free %s/%s, %p (bad vaddr)/%x\n",
pool->dev ? pool->dev->slot_name : NULL,
pool->name, vaddr, dma);
return;
}
#endif
block = dma - page->dma;
block /= pool->size;
map = block / BITS_PER_LONG;
block %= BITS_PER_LONG;
#ifdef CONFIG_PCIPOOL_DEBUG
if (page->bitmap [map] & (1UL << block)) {
printk (KERN_ERR "pci_pool_free %s/%s, dma %x already free\n",
pool->dev ? pool->dev->slot_name : NULL,
pool->name, dma);
return;
}
#endif
if (pool->flags & SLAB_POISON)
memset (vaddr, POOL_POISON_BYTE, pool->size);
spin_lock_irqsave (&pool->lock, flags);
set_bit (block, &page->bitmap [map]);
if (waitqueue_active (&pool->waitq))
wake_up (&pool->waitq);
/*
* Resist a temptation to do
* if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
* it is not interrupt safe. Better have empty pages hang around.
*/
spin_unlock_irqrestore (&pool->lock, flags);
}
EXPORT_SYMBOL (pci_pool_create);
EXPORT_SYMBOL (pci_pool_destroy);
EXPORT_SYMBOL (pci_pool_alloc);
EXPORT_SYMBOL (pci_pool_free);
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