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/*
* linux/arch/arm/mm/consistent.c
*
* Copyright (C) 2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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)
{
struct page *page, *end, *free;
unsigned long order;
void *ret, *virt;
if (in_interrupt())
BUG();
size = PAGE_ALIGN(size);
order = get_order(size);
page = alloc_pages(gfp, order);
if (!page)
goto no_page;
/*
* We could do with a page_to_phys and page_to_bus here.
*/
virt = page_address(page);
*dma_handle = virt_to_bus(virt);
ret = __ioremap(virt_to_phys(virt), size, 0);
if (!ret)
goto no_remap;
#if 0 /* ioremap_does_flush_cache_all */
/*
* we need to ensure that there are no cachelines in use, or
* worse dirty in this area. Really, we don't need to do
* this since __ioremap does a flush_cache_all() anyway. --rmk
*/
invalidate_dcache_range(virt, virt + size);
#endif
/*
* free wasted pages. We skip the first page since we know
* that it will have count = 1 and won't require freeing.
* We also mark the pages in use as reserved so that
* remap_page_range works.
*/
page = virt_to_page(virt);
free = page + (size >> PAGE_SHIFT);
end = page + (1 << order);
for (; page < end; page++) {
set_page_count(page, 1);
if (page >= free)
__free_page(page);
else
SetPageReserved(page);
}
return ret;
no_remap:
__free_pages(page, order);
no_page:
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, size_t size, dma_addr_t handle)
{
struct page *page, *end;
void *virt;
if (in_interrupt())
BUG();
virt = bus_to_virt(handle);
/*
* More messing around with the MM internals. This is
* sick, but then so is remap_page_range().
*/
size = PAGE_ALIGN(size);
page = virt_to_page(virt);
end = page + (size >> PAGE_SHIFT);
for (; page < end; page++)
ClearPageReserved(page);
__iounmap(vaddr);
}
/*
* make an area consistent.
*/
void consistent_sync(void *vaddr, size_t size, int direction)
{
unsigned long start = (unsigned long)vaddr;
unsigned long end = start + size;
switch (direction) {
case PCI_DMA_NONE:
BUG();
case PCI_DMA_FROMDEVICE: /* invalidate only */
invalidate_dcache_range(start, end);
break;
case PCI_DMA_TODEVICE: /* writeback only */
clean_dcache_range(start, end);
break;
case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */
flush_dcache_range(start, end);
break;
}
}
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