From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maxime Ripard , Ludovic Desroches , Vinod Koul Subject: [PATCH 4.2 054/258] dmaengine: at_xdmac: change block increment addressing mode Date: Sat, 17 Oct 2015 18:56:07 -0700 Message-Id: <20151018014732.778271602@linuxfoundation.org> In-Reply-To: <20151018014729.976101177@linuxfoundation.org> References: <20151018014729.976101177@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maxime Ripard commit a1cf09031e641d3cceaca4a4dd20ef6a785bc9b3 upstream. The addressing mode we were using was not only incrementing the address at each microblock, but also at each data boundary, which was severely slowing the transfer, without any benefit since we were not using the data stride. Switch to the micro block increment only in order to get back to an acceptable performance level. Signed-off-by: Maxime Ripard Signed-off-by: Ludovic Desroches Fixes: 6007ccb57744 ("dmaengine: xdmac: Add interleaved transfer support") Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/at_xdmac.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -878,14 +878,14 @@ at_xdmac_interleaved_queue_desc(struct d if (xt->src_inc) { if (xt->src_sgl) - chan_cc |= AT_XDMAC_CC_SAM_UBS_DS_AM; + chan_cc |= AT_XDMAC_CC_SAM_UBS_AM; else chan_cc |= AT_XDMAC_CC_SAM_INCREMENTED_AM; } if (xt->dst_inc) { if (xt->dst_sgl) - chan_cc |= AT_XDMAC_CC_DAM_UBS_DS_AM; + chan_cc |= AT_XDMAC_CC_DAM_UBS_AM; else chan_cc |= AT_XDMAC_CC_DAM_INCREMENTED_AM; }