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/*
* Dynamic DMA mapping support.
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
/*
* This allocates one page of cache-coherent memory space and returns
* both the virtual and a "dma" address to that space. It is not clear
* whether this could be called from an interrupt context or not. For
* now, we expressly forbid it, especially as some of the stuff we do
* here is not interrupt context safe.
*
* Note that this does *not* zero the allocated area!
*/
void *consistent_alloc(int gfp, size_t size, dma_addr_t *dma_handle)
{
int order;
unsigned long page;
void *ret;
if (in_interrupt())
BUG();
size = PAGE_ALIGN(size);
order = get_order(size);
page = __get_free_pages(gfp, order);
if (!page)
goto no_page;
ret = __ioremap(virt_to_phys((void *)page), size, 0);
if (ret) {
/* free wasted pages */
unsigned long end = page + (PAGE_SIZE << order);
/*
* we need to ensure that there are no
* cachelines in use, or worse dirty in
* this area.
*/
dma_cache_inv(page, size);
dma_cache_inv(ret, size);
*dma_handle = virt_to_bus((void *)page);
page += size;
while (page < end) {
free_page(page);
page += PAGE_SIZE;
}
return ret;
}
free_pages(page, order);
no_page:
BUG();
return NULL;
}
void *pci_alloc_consistent(struct pci_dev *hwdev, size_t size, dma_addr_t *handle)
{
void *__ret;
int __gfp = GFP_KERNEL;
#ifdef CONFIG_PCI
if ((hwdev) == NULL ||
(hwdev)->dma_mask != 0xffffffff)
#endif
__gfp |= GFP_DMA;
__ret = consistent_alloc(__gfp, (size),
(handle));
return __ret;
}
/*
* free a page as defined by the above mapping. We expressly forbid
* calling this from interrupt context.
*/
void consistent_free(void *vaddr)
{
if (in_interrupt())
BUG();
__iounmap(vaddr);
}
/*
* make an area consistent.
*/
void consistent_sync(void *vaddr, size_t size, int direction)
{
switch (direction) {
case PCI_DMA_NONE:
BUG();
case PCI_DMA_FROMDEVICE: /* invalidate only */
dma_cache_inv(vaddr, size);
break;
case PCI_DMA_TODEVICE: /* writeback only */
dma_cache_wback(vaddr, size);
break;
case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */
dma_cache_wback_inv(vaddr, size);
break;
}
}
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