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Commit c73bc702 authored by Akinobu Mita's avatar Akinobu Mita Committed by Bob Liu
Browse files

blackfin: use bitmap library functions 



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: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: uclinux-dist-devel@blackfin.uclinux.org
Signed-off-by: default avatarBob Liu <lliubbo@gmail.com>
parent c428f8eb

arch/blackfin/kernel/dma-mapping.c

+7 −16
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#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;
@@ -46,24 +47,17 @@ static inline unsigned int get_pages(size_t size) 
static unsigned long __alloc_dma_pages(unsigned int pages)

{

	unsigned long ret = 0, flags;

	int i, count = 0;

	unsigned long start;



	if (dma_initialized == 0)

		dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);



	spin_lock_irqsave(&dma_page_lock, flags);



	for (i = 0; i < dma_pages;) {

		if (test_bit(i++, dma_page) == 0) {

			if (++count == pages) {

				while (count--)

					__set_bit(--i, dma_page);



				ret = dma_base + (i << PAGE_SHIFT);

				break;

			}

		} else

			count = 0;

	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;
@@ -73,7 +67,6 @@ static void __free_dma_pages(unsigned long addr, unsigned int pages) 
{

	unsigned long page = (addr - dma_base) >> PAGE_SHIFT;

	unsigned long flags;

	int i;



	if ((page + pages) > dma_pages) {

		printk(KERN_ERR "%s: freeing outside range.\n", __func__);
@@ -81,9 +74,7 @@ static void __free_dma_pages(unsigned long addr, unsigned int pages) 
	}



	spin_lock_irqsave(&dma_page_lock, flags);

	for (i = page; i < page + pages; i++)

		__clear_bit(i, dma_page);



	bitmap_clear(dma_page, page, pages);

	spin_unlock_irqrestore(&dma_page_lock, flags);

}