Hi Tien,
On 31 May 2018 at 02:08, tien.fong.chee@intel.com wrote:
From: Tien Fong Chee tien.fong.chee@intel.com
This new DMA class function enables DMA being used for initializing a range of destination such as memory to zeros. This is quite useful to help accelerating the performance in scrubbing memory when ECC is enabled.
Signed-off-by: Tien Fong Chee tien.fong.chee@intel.com
drivers/dma/dma-uclass.c | 15 +++++++++++++++ include/dma.h | 12 ++++++++++++ 2 files changed, 27 insertions(+)
diff --git a/drivers/dma/dma-uclass.c b/drivers/dma/dma-uclass.c index a33f7d5..cb83c24 100644 --- a/drivers/dma/dma-uclass.c +++ b/drivers/dma/dma-uclass.c @@ -61,6 +61,21 @@ int dma_memcpy(void *dst, void *src, size_t len) return ops->transfer(dev, DMA_MEM_TO_MEM, dst, src, len); }
+int dma_memcpy_zeroes(struct udevice *dev, void *dst, size_t len) +{
const struct dma_ops *ops;ops = device_get_ops(dev);if (!ops->transfer_zeroes)return -ENOSYS;/* Invalidate the area, so no writeback into the RAM races with DMA */invalidate_dcache_range((unsigned long)dst, (unsigned long)dst +roundup(len, ARCH_DMA_MINALIGN));return ops->transfer_zeroes(dev, dst, len);+}
UCLASS_DRIVER(dma) = { .id = UCLASS_DMA, .name = "dma", diff --git a/include/dma.h b/include/dma.h index 50e9652..6bad2264 100644 --- a/include/dma.h +++ b/include/dma.h @@ -46,6 +46,7 @@ struct dma_ops { */ int (*transfer)(struct udevice *dev, int direction, void *dst, void *src, size_t len);
int (*transfer_zeroes)(struct udevice *dev, void *dst, size_t len);
I wonder if this could be done by using transfer() with a src of NULL ?
};
/* @@ -82,4 +83,15 @@ int dma_get_device(u32 transfer_type, struct udevice **devp); */ int dma_memcpy(void *dst, void *src, size_t len);
+/*
- dma_memcpy_zeroes - Fill up destination with zeros through DMA.
- @dev: The DMA device
- @dst: destination pointer
- @len: length to be copied with zero
- @return: on successful transfer returns zero.
on failure returns error code.- */
+int dma_memcpy_zeroes(struct udevice *dev, void *dst, size_t len);
#endif /* _DMA_H_ */
2.2.0
Regards, Simon