From patchwork Fri Oct 19 12:29:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 10649243 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EA84013A4 for ; Fri, 19 Oct 2018 12:30:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D9099286F5 for ; Fri, 19 Oct 2018 12:30:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CD1F328791; Fri, 19 Oct 2018 12:30:05 +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=-7.7 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 53E89286F5 for ; Fri, 19 Oct 2018 12:30:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727509AbeJSUfp (ORCPT ); Fri, 19 Oct 2018 16:35:45 -0400 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:44288 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726609AbeJSUfp (ORCPT ); Fri, 19 Oct 2018 16:35:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sirena.org.uk; s=20170815-heliosphere; h=Date:Message-Id:In-Reply-To: Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References: List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner: List-Archive; bh=1tJgNCU6ampVhhEakSX9sXxAB5mJeex5rc1gnKV21J0=; b=xKcjIz9TbSgm nchVGXCzyynn836eqlRzlYjRmJc0qulkMvWWbpIdJuBVULBzhNBag84pRKyY66eyphUHUV6FGCzx7 88BbcdOFDGrw4ulen920POVon1Vsf7ZF3h0mYyUzjvJqa7Ms7DZenMOzy50My0tka7oO9d5BHWwvN H7Dzs=; Received: from cpc102320-sgyl38-2-0-cust46.18-2.cable.virginm.net ([82.37.168.47] helo=debutante.sirena.org.uk) by heliosphere.sirena.org.uk with esmtpa (Exim 4.89) (envelope-from ) id 1gDTuW-00004x-AP; Fri, 19 Oct 2018 12:29:48 +0000 Received: by debutante.sirena.org.uk (Postfix, from userid 1000) id 131CE1122548; Fri, 19 Oct 2018 13:29:48 +0100 (BST) From: Mark Brown To: Vignesh R Cc: Mark Brown , Mark Brown , linux-spi@vger.kernel.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, Sekhar Nori , linux-spi@vger.kernel.org Subject: Applied "spi: omap2-mcspi: Set FIFO DMA trigger level to word length" to the spi tree In-Reply-To: <20181015063829.26978-3-vigneshr@ti.com> Message-Id: <20181019122948.131CE1122548@debutante.sirena.org.uk> Date: Fri, 19 Oct 2018 13:29:48 +0100 (BST) Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The patch spi: omap2-mcspi: Set FIFO DMA trigger level to word length has been applied to the spi tree at https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark From c367dadf3cfda3760005eecb7613db49bd9aba7c Mon Sep 17 00:00:00 2001 From: Vignesh R Date: Mon, 15 Oct 2018 12:08:28 +0530 Subject: [PATCH] spi: omap2-mcspi: Set FIFO DMA trigger level to word length McSPI has 32 byte FIFO in Transmit-Receive mode. Current code tries to configuration FIFO watermark level for DMA trigger to be GCD of transfer length and max FIFO size which would mean trigger level may be set to 32 for transmit-receive mode if length is aligned. This does not work in case of SPI slave mode where FIFO always needs to have data ready whenever master starts the clock. With DMA trigger size of 32 there will be a small window during slave TX where DMA is still putting data into FIFO but master would have started clock for next byte, resulting in shifting out of stale data. Similarly, on Slave RX side there may be RX FIFO overflow Fix this by setting FIFO watermark for DMA trigger to word length. This means DMA is triggered as soon as FIFO has space for word length bytes and DMA would make sure FIFO is almost always full therefore improving FIFO occupancy in both master and slave mode. Signed-off-by: Vignesh R Signed-off-by: Mark Brown --- drivers/spi/spi-omap2-mcspi.c | 26 +++++++------------------- 1 file changed, 7 insertions(+), 19 deletions(-) diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index 985f00d8a964..88469bb22235 100644 --- a/drivers/spi/spi-omap2-mcspi.c +++ b/drivers/spi/spi-omap2-mcspi.c @@ -300,7 +300,7 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi, struct omap2_mcspi_cs *cs = spi->controller_state; struct omap2_mcspi *mcspi; unsigned int wcnt; - int max_fifo_depth, fifo_depth, bytes_per_word; + int max_fifo_depth, bytes_per_word; u32 chconf, xferlevel; mcspi = spi_master_get_devdata(master); @@ -316,10 +316,6 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi, else max_fifo_depth = OMAP2_MCSPI_MAX_FIFODEPTH; - fifo_depth = gcd(t->len, max_fifo_depth); - if (fifo_depth < 2 || fifo_depth % bytes_per_word != 0) - goto disable_fifo; - wcnt = t->len / bytes_per_word; if (wcnt > OMAP2_MCSPI_MAX_FIFOWCNT) goto disable_fifo; @@ -327,16 +323,17 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi, xferlevel = wcnt << 16; if (t->rx_buf != NULL) { chconf |= OMAP2_MCSPI_CHCONF_FFER; - xferlevel |= (fifo_depth - 1) << 8; + xferlevel |= (bytes_per_word - 1) << 8; } + if (t->tx_buf != NULL) { chconf |= OMAP2_MCSPI_CHCONF_FFET; - xferlevel |= fifo_depth - 1; + xferlevel |= bytes_per_word - 1; } mcspi_write_reg(master, OMAP2_MCSPI_XFERLEVEL, xferlevel); mcspi_write_chconf0(spi, chconf); - mcspi->fifo_depth = fifo_depth; + mcspi->fifo_depth = max_fifo_depth; return; } @@ -576,7 +573,6 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer) struct dma_slave_config cfg; enum dma_slave_buswidth width; unsigned es; - u32 burst; void __iomem *chstat_reg; void __iomem *irqstat_reg; int wait_res; @@ -596,22 +592,14 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer) } count = xfer->len; - burst = 1; - - if (mcspi->fifo_depth > 0) { - if (count > mcspi->fifo_depth) - burst = mcspi->fifo_depth / es; - else - burst = count / es; - } memset(&cfg, 0, sizeof(cfg)); cfg.src_addr = cs->phys + OMAP2_MCSPI_RX0; cfg.dst_addr = cs->phys + OMAP2_MCSPI_TX0; cfg.src_addr_width = width; cfg.dst_addr_width = width; - cfg.src_maxburst = burst; - cfg.dst_maxburst = burst; + cfg.src_maxburst = es; + cfg.dst_maxburst = es; rx = xfer->rx_buf; tx = xfer->tx_buf;