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Commit f924baa2 authored by Shiraz Hashim's avatar Shiraz Hashim
Browse files

drivers: dma: map pages only if required 



DMA clients such as PIL would often allocate large
contiguous physical memory through dma-removed interface
for carve-outs. It may not be possible to map these large
allocations due to insufficient vmalloc space.

Hence provide provision to map the allocated pages only
if mapping or zeroing is explicitly requested for.

Change-Id: I1bfea1223e9ba9819b7768e01d5910690ea0f281
Signed-off-by: default avatarShiraz Hashim <shashim@codeaurora.org>
parent 5286facb

drivers/base/dma-removed.c

+7 −1
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ void *removed_alloc(struct device *dev, size_t size, dma_addr_t *handle, 
{

	bool no_kernel_mapping = dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING,

					attrs);

	bool skip_zeroing = dma_get_attr(DMA_ATTR_SKIP_ZEROING, attrs);

	unsigned long pfn;

	unsigned long order = get_order(size);

	void *addr = NULL;
@@ -43,11 +44,16 @@ void *removed_alloc(struct device *dev, size_t size, dma_addr_t *handle, 
	pfn = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT, order);



	if (pfn) {

		if (no_kernel_mapping && skip_zeroing) {

			*handle = __pfn_to_phys(pfn);

			return (void *)NO_KERNEL_MAPPING_DUMMY;

		}



		addr = ioremap(__pfn_to_phys(pfn), size);

		if (WARN_ON(!addr)) {

			dma_release_from_contiguous(dev, pfn, order);

		} else {

			if (!dma_get_attr(DMA_ATTR_SKIP_ZEROING, attrs))

			if (!skip_zeroing)

				memset(addr, 0, size);

			if (no_kernel_mapping) {

				iounmap(addr);