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arm64: handle non-cacheable normal memory

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Non-cacheable normal memory is needed when one wants an easy way
to have a DMA region. That way all the reads and writes will be
picked up by the CPU and the device without any cache management
operations.

BUG=chrome-os-partner:31293
BRANCH=None
TEST=With a bevy of other patches can use a carved out DMA region
     for talking to USB.

Change-Id: I36b7fc276467fe3e9cec4d602652d6fa8098c133
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/212160
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
This commit is contained in:
Aaron Durbin 2014-08-12 17:40:38 -05:00 • committed by chrome-internal-fetch
commit a5bc7ab170
2 changed files with 13 additions and 2 deletions
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12
src/arch/arm64/armv8/mmu.c
View file

@ -67,8 +67,16 @@ static uint64_t get_block_attr(unsigned long tag)
attr = (tag & MA_NS)? BLOCK_NS : 0;
attr |= (tag & MA_RO)? BLOCK_AP_RO : BLOCK_AP_RW;
attr |= BLOCK_ACCESS;
attr |= (tag & MA_MEM)? (BLOCK_INDEX_MEM_NORMAL << BLOCK_INDEX_SHIFT) :
(BLOCK_INDEX_MEM_DEV_NGNRNE << BLOCK_INDEX_SHIFT);
if (tag & MA_MEM) {
if (tag & MA_MEM_NC)
attr |= BLOCK_INDEX_MEM_NORMAL_NC << BLOCK_INDEX_SHIFT;
else
attr |= BLOCK_INDEX_MEM_NORMAL << BLOCK_INDEX_SHIFT;
} else {
attr |= BLOCK_INDEX_MEM_DEV_NGNRNE << BLOCK_INDEX_SHIFT;
}
return attr;
}

3
src/arch/arm64/include/armv8/arch/mmu.h
View file

@ -47,6 +47,9 @@
#define MA_RO (1 << 2)
#define MA_RW (0 << 2)
/* Non-cacheable memory. */
#define MA_MEM_NC (1 << 3)
/* Descriptor attributes */
#define INVALID_DESC 0x0