From patchwork Fri Nov 18 08:04:03 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sanchayan X-Patchwork-Id: 9435933 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 170A560469 for ; Fri, 18 Nov 2016 08:20:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 05308293C7 for ; Fri, 18 Nov 2016 08:20:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EB19429829; Fri, 18 Nov 2016 08:20:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,FREEMAIL_FROM,RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 82C33293C7 for ; Fri, 18 Nov 2016 08:20:27 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1c7eNl-0004yv-CJ; Fri, 18 Nov 2016 08:18:49 +0000 Received: from mail-pf0-x244.google.com ([2607:f8b0:400e:c00::244]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1c7eIS-0006XB-Im for linux-arm-kernel@lists.infradead.org; Fri, 18 Nov 2016 08:14:01 +0000 Received: by mail-pf0-x244.google.com with SMTP id i88so13100732pfk.2 for ; Fri, 18 Nov 2016 00:13:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=fCHuYclgXmBpKTiCta4RNR6cgXppkRUOOG1ZZ3eg1D0=; b=Ecr+JyVPq/5HK3mmc/t/bHULvpUZsHGTmzm6IjMaO4oRDQRS4jfRrw2J4z35Lbd5zo cBiYnJ/mwBFlTDHdSj2rETaviaY75eV/8Oko0oLtqq9iRHKdsf/FGP96KxLIVppVmX4r VrZVfhtVhPBcxWKJXwEVaOjNij1VsP3mwhoyGWW7nUlUsFEIu2hIgNya+IZ59uJ11P5Z vaDAlZ7vUut0Fe+8S8eQZfvGeQ3AiU/9aRHXQYS7kFcrprBFA1mo5HlYrZOBH+dIKjb9 rqi62ma6wmBqjlKs6ll3UJKpWBhdXRBK9Dllf4K3PovCVgF5crBKYHxwBK31yESOLrI5 cegQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=fCHuYclgXmBpKTiCta4RNR6cgXppkRUOOG1ZZ3eg1D0=; b=hvLzdh1B6Sr47Rt0N0TsyqRDyUMmKWXjWpKPTwxx3NnGuc8hz9FShJ1/ng0PacANSY AYRuE6/Qwc9pxT6EeaF3eKbtV6RftZfsIP8qtVp3HsO78SnFceomFksh+a0Xc4fm6M1o wb8RGl5PCiOdJmvamb2mD9fQKofM2YT9tgZRzg0j/Ov+DzG2xnDvUgKnoTLrnhC8EhFk n86TV0Dbxa4cfnK1gksreB+dQ8vADfk1WcgclBVAj9e59TwH/fpUFZLRPn8aa+mZIMis PnJ2gA3OZ/QBbk+Zb0sTlpdD/cRNFd4DMTnqznAjkVQY6LIZqrdBuPtA+N/ecgitfool Y+pQ== X-Gm-Message-State: ABUngvfwP6/GQJp2V+QKlumiJ19T1fIawcSuwIVu6IVgi4D3hjeQ8SD9ngPeUuCRfhn11Q== X-Received: by 10.99.5.21 with SMTP id 21mr16477701pgf.32.1479456779466; Fri, 18 Nov 2016 00:12:59 -0800 (PST) Received: from localhost ([115.115.243.34]) by smtp.gmail.com with ESMTPSA id c128sm14818228pfc.39.2016.11.18.00.12.58 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 18 Nov 2016 00:12:58 -0800 (PST) Date: Fri, 18 Nov 2016 13:34:03 +0530 From: maitysanchayan@gmail.com To: Stefan Agner Subject: Re: [PATCH 2/4] spi: spi-fsl-dspi: Fix incorrect DMA setup Message-ID: <20161118080403.GB1572@Sanchayan-Arch.localdomain> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.7.1 (2016-10-04) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161118_001321_439736_63F2B36D X-CRM114-Status: GOOD ( 23.69 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: broonie@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP On 16-11-17 17:03:19, Stefan Agner wrote: > On 2016-11-17 04:16, Sanchayan Maity wrote: > > 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, > > Hm, this is getting ridiculous, I think we convert curr_xfer_len from > bytes to DMA transfers in almost every use. > > Can we make it be transfer length in actual 4 byte transfers? We then > probably have to convert it to bytes once to subtract from > curr_remaining_bytes, but I think it would simplify code overall... Will the below be acceptable fix? Regards, Sanchayan. > > -- > Stefan > > > > 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"); diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c index 41422cd..db7f091 100644 --- a/drivers/spi/spi-fsl-dspi.c +++ b/drivers/spi/spi-fsl-dspi.c @@ -217,15 +217,13 @@ static void dspi_rx_dma_callback(void *arg) struct fsl_dspi *dspi = arg; struct fsl_dspi_dma *dma = dspi->dma; int rx_word; - int i, len; + int i; u16 d; rx_word = is_double_byte_mode(dspi); - len = rx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len; - if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) { - for (i = 0; i < len; i++) { + for (i = 0; i < dma->curr_xfer_len; i++) { d = dspi->dma->rx_dma_buf[i]; rx_word ? (*(u16 *)dspi->rx = d) : (*(u8 *)dspi->rx = d); @@ -242,14 +240,12 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi) struct device *dev = &dspi->pdev->dev; int time_left; int tx_word; - int i, len; + int i; u16 val; tx_word = is_double_byte_mode(dspi); - len = tx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len; - - for (i = 0; i < len - 1; i++) { + for (i = 0; i < dma->curr_xfer_len - 1; i++) { val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx; dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) | @@ -267,7 +263,9 @@ 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, + 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"); @@ -283,7 +281,9 @@ 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, + 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"); @@ -330,17 +330,17 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi) struct device *dev = &dspi->pdev->dev; int curr_remaining_bytes; int bytes_per_buffer; - int tx_word; + int tx_word = 1; int ret = 0; - tx_word = is_double_byte_mode(dspi); + if (is_double_byte_mode(dspi)) + tx_word = 2; curr_remaining_bytes = dspi->len; + bytes_per_buffer = DSPI_DMA_BUFSIZE / DSPI_FIFO_SIZE; while (curr_remaining_bytes) { /* Check if current transfer fits the DMA buffer */ - dma->curr_xfer_len = curr_remaining_bytes; - bytes_per_buffer = DSPI_DMA_BUFSIZE / - (DSPI_FIFO_SIZE / (tx_word ? 2 : 1)); - if (curr_remaining_bytes > bytes_per_buffer) + dma->curr_xfer_len = curr_remaining_bytes / tx_word; + if (dma->curr_xfer_len > bytes_per_buffer) dma->curr_xfer_len = bytes_per_buffer; ret = dspi_next_xfer_dma_submit(dspi); @@ -349,7 +349,7 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi) goto exit; } else { - curr_remaining_bytes -= dma->curr_xfer_len; + curr_remaining_bytes -= dma->curr_xfer_len * tx_word; if (curr_remaining_bytes < 0) curr_remaining_bytes = 0; dspi->len = curr_remaining_bytes;