[mm PATCH v3 02/23] arch/arm: Add option to skip sync on DMA map and unmap

From: Alexander Duyck
Date: Thu Nov 10 2016 - 12:35:45 EST


The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the DMA
APIs in the arch/arm folder. This change is meant to correct that so that
we get consistent behavior.

Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
---
arch/arm/common/dmabounce.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 3012816..75055df 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -243,7 +243,8 @@ static int needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
}

static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
- enum dma_data_direction dir)
+ enum dma_data_direction dir,
+ unsigned long attrs)
{
struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
struct safe_buffer *buf;
@@ -262,7 +263,8 @@ static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
buf->safe, buf->safe_dma_addr);

- if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
+ if ((dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
__func__, ptr, buf->safe, size);
memcpy(buf->safe, ptr, size);
@@ -272,7 +274,8 @@ static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
}

static inline void unmap_single(struct device *dev, struct safe_buffer *buf,
- size_t size, enum dma_data_direction dir)
+ size_t size, enum dma_data_direction dir,
+ unsigned long attrs)
{
BUG_ON(buf->size != size);
BUG_ON(buf->direction != dir);
@@ -283,7 +286,8 @@ static inline void unmap_single(struct device *dev, struct safe_buffer *buf,

DO_STATS(dev->archdata.dmabounce->bounce_count++);

- if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
+ if ((dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
void *ptr = buf->ptr;

dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
@@ -334,7 +338,7 @@ static dma_addr_t dmabounce_map_page(struct device *dev, struct page *page,
return DMA_ERROR_CODE;
}

- return map_single(dev, page_address(page) + offset, size, dir);
+ return map_single(dev, page_address(page) + offset, size, dir, attrs);
}

/*
@@ -357,7 +361,7 @@ static void dmabounce_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t
return;
}

- unmap_single(dev, buf, size, dir);
+ unmap_single(dev, buf, size, dir, attrs);
}

static int __dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,