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xtensa: support DMA_ATTR_NO_KERNEL_MAPPING attribute

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An application that doesn't need kernel mapping of the DMA memory it
allocates may specify DMA_ATTR_NO_KERNEL_MAPPING attribute to allocation
function. Support this attribute and return address of the first struct
page that covers the allocation.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2018-02-14 16:12:54 -08:00
parent 3f2bbf443e
commit adbfa4e6f9
1 changed files with 8 additions and 2 deletions
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10
arch/xtensa/kernel/pci-dma.c
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@ -116,6 +116,10 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
*handle = phys_to_dma(dev, page_to_phys(page));
if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
return page;
}
#ifdef CONFIG_MMU
if (PageHighMem(page)) {
void *p;
@ -147,8 +151,10 @@ void arch_dma_free(struct device *dev, size_t size, void *vaddr,
unsigned long addr = (unsigned long)vaddr;
struct page *page;
if (addr >= XCHAL_KSEG_BYPASS_VADDR &&
addr - XCHAL_KSEG_BYPASS_VADDR < XCHAL_KSEG_SIZE) {
if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
page = vaddr;
} else 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 {