From patchwork Thu Jun 22 09:06:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 697178 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 306A4EB64DB for ; Thu, 22 Jun 2023 09:15:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230506AbjFVJPe (ORCPT ); Thu, 22 Jun 2023 05:15:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232387AbjFVJOy (ORCPT ); Thu, 22 Jun 2023 05:14:54 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42D627EDA for ; Thu, 22 Jun 2023 02:06:39 -0700 (PDT) X-GND-Sasl: miquel.raynal@bootlin.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1687424798; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I2183b6oDtby4XAIhp5msAg+vrfOlFnEs4/AO2GjwDM=; b=iVQtyiRuPipbaG/ykeAFvBFn49hkb2v9AQ9KnuvgqDJBW/KZzi9nwysilXKeIpFGdN7XPc fAfOVRAuuJMRHwMzcrc/vjiirp7bF0jEEFPfqrT8WfV/+QHNyswY/RSDOKNFwzKGPNrLnU Cbc1Fhy/ar6AUGzqYMR4E5K2foGRIoD/SkHoG18G4ycvQFldWDSJgu66m7UW+jxdWJ6SfD uZ3tQHjR0mUT5x+qEUAK/wf1gNMukVEI7k5h2qnd+6tPUeWRjNiWv/t7xL+IPMZSKh2l0T viTDH8m8wYGmBAfhH1YbSbNYUhd3aYzPg9XENJX05T+HtGScWXelUE6cznv1YQ== X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com Received: by mail.gandi.net (Postfix) with ESMTPSA id 62D8B40008; Thu, 22 Jun 2023 09:06:37 +0000 (UTC) From: Miquel Raynal To: Mark Brown , Cc: Thomas Petazzoni , Tudor Ambarus , Nicolas Ferre , Claudiu Beznea , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , , Miquel Raynal Subject: [PATCH v3 2/3] spi: atmel: Prevent false timeouts on long transfers Date: Thu, 22 Jun 2023 11:06:33 +0200 Message-Id: <20230622090634.3411468-3-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230622090634.3411468-1-miquel.raynal@bootlin.com> References: <20230622090634.3411468-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org A slow SPI bus clocks at ~20MHz, which means it would transfer about 2500 bytes per second with a single data line. Big transfers, like when dealing with flashes can easily reach a few MiB. The current DMA timeout is set to 1 second, which means any working transfer of about 4MiB will always be cancelled. With the above derivations, on a slow bus, we can assume every byte will take at most 0.4ms. Said otherwise, we could add 4ms to the 1-second timeout delay every 10kiB. On a 4MiB transfer, it would bring the timeout delay up to 2.6s which still seems rather acceptable for a timeout. The consequence of this is that long transfers might be allowed, which hence requires the need to interrupt the transfer if wanted by the user. We can hence switch to the _interruptible variant of wait_for_completion. This leads to a little bit more handling to also handle the interrupted case but looks really acceptable overall. While at it, we drop the useless, noisy and redundant WARN_ON() call. Signed-off-by: Miquel Raynal --- drivers/spi/spi-atmel.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 943548aab8af..d87be2890597 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -233,7 +233,8 @@ */ #define DMA_MIN_BYTES 16 -#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000)) +#define SPI_DMA_MIN_TIMEOUT (msecs_to_jiffies(1000)) +#define SPI_DMA_TIMEOUT_PER_10K (msecs_to_jiffies(4)) #define AUTOSUSPEND_TIMEOUT 2000 @@ -1279,7 +1280,8 @@ static int atmel_spi_one_transfer(struct spi_controller *host, struct atmel_spi_device *asd; int timeout; int ret; - unsigned long dma_timeout; + unsigned int dma_timeout; + long ret_timeout; as = spi_controller_get_devdata(host); @@ -1333,11 +1335,13 @@ static int atmel_spi_one_transfer(struct spi_controller *host, atmel_spi_unlock(as); } - dma_timeout = wait_for_completion_timeout(&as->xfer_completion, - SPI_DMA_TIMEOUT); - if (WARN_ON(dma_timeout == 0)) { - dev_err(&spi->dev, "spi transfer timeout\n"); - as->done_status = -EIO; + dma_timeout = msecs_to_jiffies(spi_controller_xfer_timeout(host, xfer)); + ret_timeout = wait_for_completion_interruptible_timeout(&as->xfer_completion, + dma_timeout); + if (ret_timeout <= 0) { + dev_err(&spi->dev, "spi transfer %s\n", + !ret_timeout ? "timeout" : "canceled"); + as->done_status = ret_timeout < 0 ? ret_timeout : -EIO; } if (as->done_status)