Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754832AbcKQSsW (ORCPT ); Thu, 17 Nov 2016 13:48:22 -0500 Received: from mail-pg0-f67.google.com ([74.125.83.67]:36258 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752672AbcKQSsU (ORCPT ); Thu, 17 Nov 2016 13:48:20 -0500 From: Sanchayan Maity To: broonie@kernel.org Cc: stefan@agner.ch, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, Sanchayan Maity Subject: [PATCH 2/4] spi: spi-fsl-dspi: Fix incorrect DMA setup Date: Thu, 17 Nov 2016 17:46:49 +0530 Message-Id: X-Mailer: git-send-email 2.10.2 In-Reply-To: References: <20161111122036.fubv7b4jc5vkdxhc@sirena.org.uk> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1518 Lines: 41 Currently dmaengine_prep_slave_single was being called with length set to the complete DMA buffer size. This resulted in unwanted bytes being transferred to the SPI register leading to clock and MOSI lines having unwanted data even after chip select got deasserted and the required bytes having been transferred. Signed-off-by: Sanchayan Maity --- drivers/spi/spi-fsl-dspi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c index b1ee1f5..aee8c88 100644 --- a/drivers/spi/spi-fsl-dspi.c +++ b/drivers/spi/spi-fsl-dspi.c @@ -265,7 +265,10 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi) dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx, dma->tx_dma_phys, - DSPI_DMA_BUFSIZE, DMA_MEM_TO_DEV, + dma->curr_xfer_len * + DMA_SLAVE_BUSWIDTH_4_BYTES / + (tx_word ? 2 : 1), + DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!dma->tx_desc) { dev_err(dev, "Not able to get desc for DMA xfer\n"); @@ -281,7 +284,10 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi) dma->rx_desc = dmaengine_prep_slave_single(dma->chan_rx, dma->rx_dma_phys, - DSPI_DMA_BUFSIZE, DMA_DEV_TO_MEM, + dma->curr_xfer_len * + DMA_SLAVE_BUSWIDTH_4_BYTES / + (tx_word ? 2 : 1), + DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!dma->rx_desc) { dev_err(dev, "Not able to get desc for DMA xfer\n"); -- 2.10.2