From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rameshwar Prasad Sahu Subject: [PATCH] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Date: Thu, 8 Oct 2015 13:55:16 +0530 Message-ID: <1444292716-1877-1-git-send-email-rsahu@apm.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: vinod.koul@intel.com, dan.j.williams@intel.com Cc: dmaengine@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, jcm@redhat.com, patches@apm.com, Rameshwar Prasad Sahu List-Id: devicetree@vger.kernel.org The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other computations. But the bandwidth of the entire DMA engine is shared among all channels. This patch re-configures operations availability such that one can achieve maximum performance for XOR and PQ computation by removing the memory offload operations. Signed-off-by: Rameshwar Prasad Sahu --- drivers/dma/xgene-dma.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c index 8d57b1b..2998fcb 100644 --- a/drivers/dma/xgene-dma.c +++ b/drivers/dma/xgene-dma.c @@ -154,6 +154,7 @@ #define XGENE_DMA_MAX_XOR_SRC 5 #define XGENE_DMA_16K_BUFFER_LEN_CODE 0x0 #define XGENE_DMA_INVALID_LEN_CODE 0x7800000000000000ULL +#undef XGENE_DMA_MEMCPY_ENABLE /* X-Gene DMA descriptor error codes */ #define ERR_DESC_AXI 0x01 @@ -1707,7 +1708,9 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, dma_cap_zero(dma_dev->cap_mask); /* Set DMA device capability */ +#ifdef XGENE_DMA_MEMCPY_ENABLE dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); +#endif dma_cap_set(DMA_SG, dma_dev->cap_mask); /* Basically here, the X-Gene SoC DMA engine channel 0 supports XOR -- 1.8.2.1