Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753256AbaGBO1E (ORCPT ); Wed, 2 Jul 2014 10:27:04 -0400 Received: from ns.mm-sol.com ([37.157.136.199]:50724 "EHLO extserv.mm-sol.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750869AbaGBO1B (ORCPT ); Wed, 2 Jul 2014 10:27:01 -0400 Message-ID: <1404311191.3622.22.camel@iivanov-dev> Subject: Re: [PATCH] spi: qup: Add DMA capabilities From: "Ivan T. Ivanov" To: Andy Gross Cc: Mark Brown , linux-spi@vger.kernel.org, Sagar Dharia , Daniel Sneddon , Bjorn Andersson , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org Date: Wed, 02 Jul 2014 17:26:31 +0300 In-Reply-To: <1403816781-31008-1-git-send-email-agross@codeaurora.org> References: <1403816781-31008-1-git-send-email-agross@codeaurora.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.1-2ubuntu2~saucy1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andy, Just few comments. On Thu, 2014-06-26 at 16:06 -0500, Andy Gross wrote: > This patch adds DMA capabilities to the spi-qup driver. If DMA channels are > present, the QUP will use DMA instead of block mode for transfers to/from SPI > peripherals for transactions larger than the length of a block. > > Signed-off-by: Andy Gross > --- > .../devicetree/bindings/spi/qcom,spi-qup.txt | 10 + > drivers/spi/spi-qup.c | 361 ++++++++++++++++++-- > 2 files changed, 350 insertions(+), 21 deletions(-) > > diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c > index fc1de86..9b01db5 100644 > --- a/drivers/spi/spi-qup.c > +++ b/drivers/spi/spi-qup.c > @@ -22,6 +22,8 @@ > #include > #include > #include > +#include > +#include > > #define QUP_CONFIG 0x0000 > #define QUP_STATE 0x0004 > @@ -116,6 +118,8 @@ > > #define SPI_NUM_CHIPSELECTS 4 > > +#define SPI_MAX_XFER (SZ_64K - 64) > + > /* high speed mode is when bus rate is greater then 26MHz */ > #define SPI_HS_MIN_RATE 26000000 > #define SPI_MAX_RATE 50000000 > @@ -142,6 +146,17 @@ struct spi_qup { > int w_size; /* bytes per SPI word */ > int tx_bytes; > int rx_bytes; > + > + int use_dma; > + > + struct dma_chan *rx_chan; > + struct dma_slave_config rx_conf; > + struct dma_chan *tx_chan; > + struct dma_slave_config tx_conf; > + dma_addr_t rx_dma; > + dma_addr_t tx_dma; DMA addresses seems unused. > + void *dummy; This is not so dummy, probably 'spare'. > + atomic_t dma_outstanding; > }; > > > @@ -632,6 +896,56 @@ static int spi_qup_probe(struct platform_device *pdev) > writel_relaxed(SPI_ERROR_CLK_UNDER_RUN | SPI_ERROR_CLK_OVER_RUN, > base + SPI_ERROR_FLAGS_EN); > > + /* allocate dma resources, if available */ > + controller->rx_chan = dma_request_slave_channel(&pdev->dev, "rx"); > + if (controller->rx_chan) { > + controller->tx_chan = > + dma_request_slave_channel(&pdev->dev, "tx"); > + > + if (!controller->tx_chan) { > + dev_err(&pdev->dev, "Failed to allocate dma tx chan"); > + dma_release_channel(controller->rx_chan); There is no point to go further with DMA configuration if there are no channels, right? > + } > + > + /* set DMA parameters */ > + controller->rx_conf.device_fc = 1; > + controller->rx_conf.src_addr = res->start + QUP_INPUT_FIFO; > + controller->rx_conf.src_maxburst = controller->in_blk_sz; > + > + controller->tx_conf.device_fc = 1; > + controller->tx_conf.dst_addr = res->start + QUP_OUTPUT_FIFO; > + controller->tx_conf.dst_maxburst = controller->out_blk_sz; > + Please, could you share blsp2_bam device node configuration? I would like to test these changes. Regards, Ivan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/