diff options
| author | Andrey Smirnov <andrew.smirnov@gmail.com> | 2018-08-23 19:54:21 -0700 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2018-08-24 10:12:02 +0200 |
| commit | 4e0112568c318b666624e51f91073bac03b6006b (patch) | |
| tree | 90d6e9589e783b3bd13abd3f294c99725bcb142b /arch/arm/cpu | |
| parent | dd36eef35fba38972d1fcb358969d5ac5003dcb3 (diff) | |
| download | barebox-4e0112568c318b666624e51f91073bac03b6006b.tar.gz barebox-4e0112568c318b666624e51f91073bac03b6006b.tar.xz | |
ARM: mmu64: Don't flush freshly invalidated region
Current code for dma_sync_single_for_device(), when called with dir
set to DMA_FROM_DEVICE, will first invalidate given region of memory
as a first step and then clean+invalidate it as a second. While the
second step should be harmless it seems to be an unnecessary no-op
that could probably be avoided.
Analogous code in Linux kernel (4.18) in arch/arm64/mm/cache.S:
ENTRY(__dma_map_area)
cmp w2, #DMA_FROM_DEVICE
b.eq __dma_inv_area
b __dma_clean_area
ENDPIPROC(__dma_map_area)
is written to only perform either invalidate or clean, depending on
the direction, so change dma_sync_single_for_device() to behave in the
same vein and perfom _either_ invlidate or flush of the given region.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'arch/arm/cpu')
| -rw-r--r-- | arch/arm/cpu/mmu_64.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c index b6287aec89..69d1b20718 100644 --- a/arch/arm/cpu/mmu_64.c +++ b/arch/arm/cpu/mmu_64.c @@ -297,7 +297,8 @@ void dma_sync_single_for_device(dma_addr_t address, size_t size, { if (dir == DMA_FROM_DEVICE) v8_inv_dcache_range(address, address + size - 1); - v8_flush_dcache_range(address, address + size - 1); + else + v8_flush_dcache_range(address, address + size - 1); } dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size, |