dma-alloc.c
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/* MN10300 Dynamic DMA mapping support
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* Derived from: arch/i386/kernel/pci-dma.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <asm/io.h>
static unsigned long pci_sram_allocated = 0xbc000000;
void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, int gfp)
{
unsigned long addr;
void *ret;
pr_debug("dma_alloc_coherent(%s,%zu,%x)\n",
dev ? dev_name(dev) : "?", size, gfp);
if (0xbe000000 - pci_sram_allocated >= size) {
size = (size + 255) & ~255;
addr = pci_sram_allocated;
pci_sram_allocated += size;
ret = (void *) addr;
goto done;
}
/* ignore region specifiers */
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
gfp |= GFP_DMA;
addr = __get_free_pages(gfp, get_order(size));
if (!addr)
return NULL;
/* map the coherent memory through the uncached memory window */
ret = (void *) (addr | 0x20000000);
/* fill the memory with obvious rubbish */
memset((void *) addr, 0xfb, size);
/* write back and evict all cache lines covering this region */
mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
done:
*dma_handle = virt_to_bus((void *) addr);
printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle);
return ret;
}
EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle)
{
unsigned long addr = (unsigned long) vaddr & ~0x20000000;
if (addr >= 0x9c000000)
return;
free_pages(addr, get_order(size));
}
EXPORT_SYMBOL(dma_free_coherent);