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xtensa: support DMA buffers in high memory 

If a DMA buffer is allocated in high memory and kernel mapping is
required use dma_common_contiguous_remap to map buffer to the vmalloc
region and dma_common_free_remap to unmap it.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
zero-colors
Max Filippov 2018-02-14 16:12:54 -08:00
parent 6ac5a11dc6
commit 6137e41660
1 changed files with 30 additions and 10 deletions
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40
arch/xtensa/kernel/pci-dma.c
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@ -16,6 +16,7 @@
*/
#include <linux/dma-contiguous.h>
#include <linux/dma-direct.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/mm.h>
@ -123,7 +124,7 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
unsigned long attrs)
{
unsigned long ret;
unsigned long uncached = 0;
unsigned long uncached;
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
struct page *page = NULL;
@ -144,15 +145,27 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
if (!page)
return NULL;
*handle = phys_to_dma(dev, page_to_phys(page));
#ifdef CONFIG_MMU
if (PageHighMem(page)) {
void *p;
p = dma_common_contiguous_remap(page, size, VM_MAP,
pgprot_noncached(PAGE_KERNEL),
__builtin_return_address(0));
if (!p) {
if (!dma_release_from_contiguous(dev, page, count))
__free_pages(page, get_order(size));
}
return p;
}
#endif
ret = (unsigned long)page_address(page);
/* We currently don't support coherent memory outside KSEG */
BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
*handle = virt_to_bus((void *)ret);
__invalidate_dcache_range(ret, size);
return (void *)uncached;
@ -161,13 +174,20 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
static void xtensa_dma_free(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle, unsigned long attrs)
{
unsigned long addr = (unsigned long)vaddr +
XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
struct page *page = virt_to_page(addr);
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long addr = (unsigned long)vaddr;
struct page *page;
BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
if (addr >= XCHAL_KSEG_BYPASS_VADDR &&
addr - XCHAL_KSEG_BYPASS_VADDR < XCHAL_KSEG_SIZE) {
addr += XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
page = virt_to_page(addr);
} else {
#ifdef CONFIG_MMU
dma_common_free_remap(vaddr, size, VM_MAP);
#endif
page = pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_handle)));
}
if (!dma_release_from_contiguous(dev, page, count))
__free_pages(page, get_order(size));