forked from Minki/linux
c73bc7026d
The bitmap library provides more efficient functions than accessing individual bits with bitops. This uses bitmap_find_next_zero_area() to find a continuing zero area, and uses bitmap_set()/bitmap_clear() to set/clear specified bit area. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: uclinux-dist-devel@blackfin.uclinux.org Signed-off-by: Bob Liu <lliubbo@gmail.com>
143 lines
3.3 KiB
C
143 lines
3.3 KiB
C
/*
|
|
* Dynamic DMA mapping support
|
|
*
|
|
* Copyright 2005-2009 Analog Devices Inc.
|
|
*
|
|
* Licensed under the GPL-2 or later
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/string.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/dma-mapping.h>
|
|
#include <linux/scatterlist.h>
|
|
#include <linux/export.h>
|
|
#include <linux/bitmap.h>
|
|
|
|
static spinlock_t dma_page_lock;
|
|
static unsigned long *dma_page;
|
|
static unsigned int dma_pages;
|
|
static unsigned long dma_base;
|
|
static unsigned long dma_size;
|
|
static unsigned int dma_initialized;
|
|
|
|
static void dma_alloc_init(unsigned long start, unsigned long end)
|
|
{
|
|
spin_lock_init(&dma_page_lock);
|
|
dma_initialized = 0;
|
|
|
|
dma_page = (unsigned long *)__get_free_page(GFP_KERNEL);
|
|
memset(dma_page, 0, PAGE_SIZE);
|
|
dma_base = PAGE_ALIGN(start);
|
|
dma_size = PAGE_ALIGN(end) - PAGE_ALIGN(start);
|
|
dma_pages = dma_size >> PAGE_SHIFT;
|
|
memset((void *)dma_base, 0, DMA_UNCACHED_REGION);
|
|
dma_initialized = 1;
|
|
|
|
printk(KERN_INFO "%s: dma_page @ 0x%p - %d pages at 0x%08lx\n", __func__,
|
|
dma_page, dma_pages, dma_base);
|
|
}
|
|
|
|
static inline unsigned int get_pages(size_t size)
|
|
{
|
|
return ((size - 1) >> PAGE_SHIFT) + 1;
|
|
}
|
|
|
|
static unsigned long __alloc_dma_pages(unsigned int pages)
|
|
{
|
|
unsigned long ret = 0, flags;
|
|
unsigned long start;
|
|
|
|
if (dma_initialized == 0)
|
|
dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
|
|
|
|
spin_lock_irqsave(&dma_page_lock, flags);
|
|
|
|
start = bitmap_find_next_zero_area(dma_page, dma_pages, 0, pages, 0);
|
|
if (start < dma_pages) {
|
|
ret = dma_base + (start << PAGE_SHIFT);
|
|
bitmap_set(dma_page, start, pages);
|
|
}
|
|
spin_unlock_irqrestore(&dma_page_lock, flags);
|
|
return ret;
|
|
}
|
|
|
|
static void __free_dma_pages(unsigned long addr, unsigned int pages)
|
|
{
|
|
unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
|
|
unsigned long flags;
|
|
|
|
if ((page + pages) > dma_pages) {
|
|
printk(KERN_ERR "%s: freeing outside range.\n", __func__);
|
|
BUG();
|
|
}
|
|
|
|
spin_lock_irqsave(&dma_page_lock, flags);
|
|
bitmap_clear(dma_page, page, pages);
|
|
spin_unlock_irqrestore(&dma_page_lock, flags);
|
|
}
|
|
|
|
void *dma_alloc_coherent(struct device *dev, size_t size,
|
|
dma_addr_t *dma_handle, gfp_t gfp)
|
|
{
|
|
void *ret;
|
|
|
|
ret = (void *)__alloc_dma_pages(get_pages(size));
|
|
|
|
if (ret) {
|
|
memset(ret, 0, size);
|
|
*dma_handle = virt_to_phys(ret);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(dma_alloc_coherent);
|
|
|
|
void
|
|
dma_free_coherent(struct device *dev, size_t size, void *vaddr,
|
|
dma_addr_t dma_handle)
|
|
{
|
|
__free_dma_pages((unsigned long)vaddr, get_pages(size));
|
|
}
|
|
EXPORT_SYMBOL(dma_free_coherent);
|
|
|
|
/*
|
|
* Streaming DMA mappings
|
|
*/
|
|
void __dma_sync(dma_addr_t addr, size_t size,
|
|
enum dma_data_direction dir)
|
|
{
|
|
__dma_sync_inline(addr, size, dir);
|
|
}
|
|
EXPORT_SYMBOL(__dma_sync);
|
|
|
|
int
|
|
dma_map_sg(struct device *dev, struct scatterlist *sg_list, int nents,
|
|
enum dma_data_direction direction)
|
|
{
|
|
struct scatterlist *sg;
|
|
int i;
|
|
|
|
for_each_sg(sg_list, sg, nents, i) {
|
|
sg->dma_address = (dma_addr_t) sg_virt(sg);
|
|
__dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
|
|
}
|
|
|
|
return nents;
|
|
}
|
|
EXPORT_SYMBOL(dma_map_sg);
|
|
|
|
void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg_list,
|
|
int nelems, enum dma_data_direction direction)
|
|
{
|
|
struct scatterlist *sg;
|
|
int i;
|
|
|
|
for_each_sg(sg_list, sg, nelems, i) {
|
|
sg->dma_address = (dma_addr_t) sg_virt(sg);
|
|
__dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(dma_sync_sg_for_device);
|