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Diffstat (limited to 'arch/blackfin/kernel/dma-mapping.c')
| -rw-r--r-- | arch/blackfin/kernel/dma-mapping.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/dma-mapping.c b/arch/blackfin/kernel/dma-mapping.c new file mode 100644 index 000000000000..539eb24e062f --- /dev/null +++ b/arch/blackfin/kernel/dma-mapping.c @@ -0,0 +1,183 @@ +/* + * File: arch/blackfin/kernel/dma-mapping.c + * Based on: + * Author: + * + * Created: + * Description: Dynamic DMA mapping support. + * + * Modified: + * Copyright 2004-2006 Analog Devices Inc. + * + * Bugs: Enter bugs at http://blackfin.uclinux.org/ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see the file COPYING, or write + * to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <linux/types.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/bootmem.h> +#include <linux/spinlock.h> +#include <linux/device.h> +#include <linux/dma-mapping.h> +#include <asm/cacheflush.h> +#include <asm/io.h> +#include <asm/bfin-global.h> + +static spinlock_t dma_page_lock; +static unsigned int *dma_page; +static unsigned int dma_pages; +static unsigned long dma_base; +static unsigned long dma_size; +static unsigned int dma_initialized; + +void dma_alloc_init(unsigned long start, unsigned long end) +{ + spin_lock_init(&dma_page_lock); + dma_initialized = 0; + + dma_page = (unsigned int *)__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", __FUNCTION__, + 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; + int i, count = 0; + + 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 (dma_page[i++] == 0) { + if (++count == pages) { + while (count--) + dma_page[--i] = 1; + ret = dma_base + (i << PAGE_SHIFT); + break; + } + } else + count = 0; + } + 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; + int i; + + if ((page + pages) > dma_pages) { + printk(KERN_ERR "%s: freeing outside range.\n", __FUNCTION__); + BUG(); + } + + spin_lock_irqsave(&dma_page_lock, flags); + for (i = page; i < page + pages; i++) { + dma_page[i] = 0; + } + 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); + +/* + * Dummy functions defined for some existing drivers + */ + +dma_addr_t +dma_map_single(struct device *dev, void *ptr, size_t size, + enum dma_data_direction direction) +{ + BUG_ON(direction == DMA_NONE); + + invalidate_dcache_range((unsigned long)ptr, + (unsigned long)ptr + size); + + return (dma_addr_t) ptr; +} +EXPORT_SYMBOL(dma_map_single); + +int +dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, + enum dma_data_direction direction) +{ + int i; + + BUG_ON(direction == DMA_NONE); + + for (i = 0; i < nents; i++) + invalidate_dcache_range(sg_dma_address(&sg[i]), + sg_dma_address(&sg[i]) + + sg_dma_len(&sg[i])); + + return nents; +} +EXPORT_SYMBOL(dma_map_sg); + +void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size, + enum dma_data_direction direction) +{ + BUG_ON(direction == DMA_NONE); +} +EXPORT_SYMBOL(dma_unmap_single); + +void dma_unmap_sg(struct device *dev, struct scatterlist *sg, + int nhwentries, enum dma_data_direction direction) +{ + BUG_ON(direction == DMA_NONE); +} +EXPORT_SYMBOL(dma_unmap_sg); |