From patchwork Wed Feb 17 13:28:58 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sascha Hauer X-Patchwork-Id: 8338731 Return-Path: X-Original-To: patchwork-linux-spi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 4E71CC0553 for ; Wed, 17 Feb 2016 13:29:16 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 573B32039E for ; Wed, 17 Feb 2016 13:29:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 53E5320395 for ; Wed, 17 Feb 2016 13:29:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422973AbcBQN3K (ORCPT ); Wed, 17 Feb 2016 08:29:10 -0500 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:50164 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422982AbcBQN3J (ORCPT ); Wed, 17 Feb 2016 08:29:09 -0500 Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1aW2AG-0001uQ-9W; Wed, 17 Feb 2016 14:29:08 +0100 Received: from sha by dude.hi.pengutronix.de with local (Exim 4.86) (envelope-from ) id 1aW2AA-0001Sm-T8; Wed, 17 Feb 2016 14:29:02 +0100 From: Sascha Hauer To: linux-spi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Mark Brown , Shawn Guo , Anton Bondarenko , Sascha Hauer Subject: [PATCH 12/13] spi: imx: drop bogus tests for rx/tx bufs in DMA transfer Date: Wed, 17 Feb 2016 14:28:58 +0100 Message-Id: <1455715739-25161-13-git-send-email-s.hauer@pengutronix.de> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1455715739-25161-1-git-send-email-s.hauer@pengutronix.de> References: <1455715739-25161-1-git-send-email-s.hauer@pengutronix.de> X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-spi@vger.kernel.org Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The driver tries to be clever by only setting up DMA channels when the corresponding sg tables are non NULL. The sg tables are embedded structs in struct spi_transfer, so they are guaranteed to be non NULL which makes the if(tx)/if(rx) tests completely bogus. The driver even sets the SPI_MASTER_MUST_RX / SPI_MASTER_MUST_TX flags which makes sure the sg tables are not only present but also non empty. Drop the tests and make the DMA path easier to follow. Signed-off-by: Sascha Hauer --- drivers/spi/spi-imx.c | 78 +++++++++++++++++++++------------------------------ 1 file changed, 32 insertions(+), 46 deletions(-) diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 3512c2f..9fc1de0 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -975,48 +975,37 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx, struct spi_transfer *transfer) { struct dma_async_tx_descriptor *desc_tx = NULL, *desc_rx = NULL; - int ret; unsigned long transfer_timeout; unsigned long timeout; struct spi_master *master = spi_imx->bitbang.master; struct sg_table *tx = &transfer->tx_sg, *rx = &transfer->rx_sg; - if (tx) { - desc_tx = dmaengine_prep_slave_sg(master->dma_tx, - tx->sgl, tx->nents, DMA_MEM_TO_DEV, - DMA_PREP_INTERRUPT | DMA_CTRL_ACK); - if (!desc_tx) - return -EINVAL; - - desc_tx->callback = spi_imx_dma_tx_callback; - desc_tx->callback_param = (void *)spi_imx; - dmaengine_submit(desc_tx); - } + /* + * The TX DMA setup starts the transfer, so make sure RX is configured + * before TX. + */ + desc_rx = dmaengine_prep_slave_sg(master->dma_rx, + rx->sgl, rx->nents, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc_rx) + return -EINVAL; - if (rx) { - desc_rx = dmaengine_prep_slave_sg(master->dma_rx, - rx->sgl, rx->nents, DMA_DEV_TO_MEM, - DMA_PREP_INTERRUPT | DMA_CTRL_ACK); - if (!desc_rx) - return -EINVAL; + desc_rx->callback = spi_imx_dma_rx_callback; + desc_rx->callback_param = (void *)spi_imx; + dmaengine_submit(desc_rx); + reinit_completion(&spi_imx->dma_rx_completion); + dma_async_issue_pending(master->dma_rx); - desc_rx->callback = spi_imx_dma_rx_callback; - desc_rx->callback_param = (void *)spi_imx; - dmaengine_submit(desc_rx); - } + desc_tx = dmaengine_prep_slave_sg(master->dma_tx, + tx->sgl, tx->nents, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc_tx) + return -EINVAL; - reinit_completion(&spi_imx->dma_rx_completion); + desc_tx->callback = spi_imx_dma_tx_callback; + desc_tx->callback_param = (void *)spi_imx; + dmaengine_submit(desc_tx); reinit_completion(&spi_imx->dma_tx_completion); - - /* - * Set these order to avoid potential RX overflow. The overflow may - * happen if we enable SPI HW before starting RX DMA due to rescheduling - * for another task and/or interrupt. - * So RX DMA enabled first to make sure data would be read out from FIFO - * ASAP. TX DMA enabled next to start filling TX FIFO with new data. - * And finaly SPI HW enabled to start actual data transfer. - */ - dma_async_issue_pending(master->dma_rx); dma_async_issue_pending(master->dma_tx); transfer_timeout = spi_imx_calculate_timeout(spi_imx, transfer->len); @@ -1028,22 +1017,19 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx, dev_err(spi_imx->dev, "I/O Error in DMA TX\n"); dmaengine_terminate_all(master->dma_tx); dmaengine_terminate_all(master->dma_rx); - } else { - timeout = wait_for_completion_timeout( - &spi_imx->dma_rx_completion, transfer_timeout); - if (!timeout) { - dev_err(spi_imx->dev, "I/O Error in DMA RX\n"); - spi_imx->devtype_data->reset(spi_imx); - dmaengine_terminate_all(master->dma_rx); - } + return -ETIMEDOUT; } - if (!timeout) - ret = -ETIMEDOUT; - else - ret = transfer->len; + timeout = wait_for_completion_timeout(&spi_imx->dma_rx_completion, + transfer_timeout); + if (!timeout) { + dev_err(&master->dev, "I/O Error in DMA RX\n"); + spi_imx->devtype_data->reset(spi_imx); + dmaengine_terminate_all(master->dma_rx); + return -ETIMEDOUT; + } - return ret; + return transfer->len; } static int spi_imx_pio_transfer(struct spi_device *spi,