From patchwork Fri Feb 19 07:43:01 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sascha Hauer X-Patchwork-Id: 8357041 Return-Path: X-Original-To: patchwork-linux-spi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 728C19F372 for ; Fri, 19 Feb 2016 07:43:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 84ABE203B1 for ; Fri, 19 Feb 2016 07:43:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 884FB203F3 for ; Fri, 19 Feb 2016 07:43:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161318AbcBSHnS (ORCPT ); Fri, 19 Feb 2016 02:43:18 -0500 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:55511 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161116AbcBSHnR (ORCPT ); Fri, 19 Feb 2016 02:43:17 -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 1aWfid-0003Sw-VS; Fri, 19 Feb 2016 08:43:15 +0100 Received: from sha by dude.hi.pengutronix.de with local (Exim 4.86) (envelope-from ) id 1aWfid-0007xC-28; Fri, 19 Feb 2016 08:43:15 +0100 From: Sascha Hauer To: linux-spi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Mark Brown , Anton Bondarenko Subject: [PATCH 01/12] spi: imx: allow only WML aligned transfers to use DMA Date: Fri, 19 Feb 2016 08:43:01 +0100 Message-Id: <1455867792-26389-2-git-send-email-s.hauer@pengutronix.de> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1455867792-26389-1-git-send-email-s.hauer@pengutronix.de> References: <1455867792-26389-1-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 From: Anton Bondarenko RX DMA tail data handling doesn't work correctly in many cases with current implementation. It happens because SPI core was setup to generates both RX and RX TAIL events. And RX TAIL event does not work correctly. This can be easily verified by sending SPI transaction with size modulus WML(32 in our case) not equal 0. Also this removes the change introduced in f6ee9b582 (spi: imx: Fix small DMA transfers) since this only fixes usecases with transfer size from 33 to 128 bytes and doesn't fix 129 bytes and bigger. This is output from transaction with len 138 bytes in loopback mode at 10Mhz: TX0000: a3 97 a2 55 53 be f1 fc f9 79 6b 52 14 13 e9 e2 TX0010: 2d 51 8e 1f 56 08 57 27 a7 05 d4 d0 52 82 77 75 TX0020: 1b 99 4a ed 58 3d 6a 52 36 d5 24 4a 68 8e ad 95 TX0030: 5f 3c 35 b5 c4 8c dd 6c 11 32 3d e2 b4 b4 59 cf TX0040: ce 23 3d 27 df a7 f9 96 fc 1e e0 66 2c 0e 7b 8c TX0050: ca 30 42 8f bc 9f 7b ce d1 b8 b1 87 ec 8a d6 bb TX0060: 2e 15 63 0e 3c dc a4 3a 7a 06 20 a7 93 1b 34 dd TX0070: 4c f5 ec 88 96 68 d6 68 a0 09 6f 8e 93 47 c9 41 TX0080: db ac cf 97 89 f3 51 05 79 71 RX0000: a3 97 a2 55 53 be f1 fc f9 79 6b 52 14 13 e9 e2 RX0010: 2d 51 8e 1f 56 08 57 27 a7 05 d4 d0 52 82 77 75 RX0020: 1b 99 4a ed 58 3d 6a 52 36 d5 24 4a 68 8e ad 95 RX0030: 5f 3c 35 00 00 b5 00 00 00 c4 00 00 8c 00 00 dd RX0040: 6c 11 32 3d e2 b4 b4 59 cf ce 23 3d 27 df a7 f9 RX0050: 96 fc 1e e0 66 2c 0e 7b 8c ca 30 42 8f 1f 1f bc RX0060: 9f 7b ce d1 b8 b1 87 ec 8a d6 bb 2e 15 63 0e ed RX0070: ed 3c 58 58 58 dc 3d 3d a4 6a 6a 3a 52 52 7a 36 RX0080: 06 20 a7 93 1b 34 dd 4c f5 ec Zeros at offset 33 and 34 caused by reading empty RX FIFO which not possible if DMA RX read was triggered by RX event. This mean DMA was triggered by RX TAIL event. Signed-off-by: Anton Bondarenko Signed-off--by: Sascha Hauer --- drivers/spi/spi-imx.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index d98c33c..08492d6 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -204,8 +204,8 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi, { struct spi_imx_data *spi_imx = spi_master_get_devdata(master); - if (spi_imx->dma_is_inited && - transfer->len > spi_imx->wml * sizeof(u32)) + if (spi_imx->dma_is_inited && transfer->len >= spi_imx->wml && + (transfer->len % spi_imx->wml) == 0) return true; return false; } @@ -919,8 +919,6 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx, struct dma_async_tx_descriptor *desc_tx = NULL, *desc_rx = NULL; int ret; unsigned long timeout; - u32 dma; - int left; struct spi_master *master = spi_imx->bitbang.master; struct sg_table *tx = &transfer->tx_sg, *rx = &transfer->rx_sg; @@ -954,13 +952,6 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx, /* Trigger the cspi module. */ spi_imx->dma_finished = 0; - dma = readl(spi_imx->base + MX51_ECSPI_DMA); - dma = dma & (~MX51_ECSPI_DMA_RXT_WML_MASK); - /* Change RX_DMA_LENGTH trigger dma fetch tail data */ - left = transfer->len % spi_imx->wml; - if (left) - writel(dma | (left << MX51_ECSPI_DMA_RXT_WML_OFFSET), - spi_imx->base + MX51_ECSPI_DMA); /* * Set these order to avoid potential RX overflow. The overflow may * happen if we enable SPI HW before starting RX DMA due to rescheduling @@ -992,10 +983,6 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx, spi_imx->devtype_data->reset(spi_imx); dmaengine_terminate_all(master->dma_rx); } - dma &= ~MX51_ECSPI_DMA_RXT_WML_MASK; - writel(dma | - spi_imx->wml << MX51_ECSPI_DMA_RXT_WML_OFFSET, - spi_imx->base + MX51_ECSPI_DMA); } spi_imx->dma_finished = 1;