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: 13288808 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6DB39EB64DA for ; Thu, 22 Jun 2023 09:07:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Eayw24OFoRz8LSZP2m+jFhTmGgPVPT/xCagEgTq54+U=; b=BOgnl9SA974OAR nWaJtD2egbIsb4lfhUfKteSXtSLZ0RmSPY3gQOzttl20yRPxln1fnkPcp9taBtbKis1vmJtOSijyM q5xtsBkjInVesArmm9mByXUkyDLwf/BYPvtjAz7imGgPR3NxK/s7q46cZOu+j834E7QBb48VmbYYj 0K2VS1g6+218fln1ZBLR3UJ0QLrOgF2QMkv9nYmRjE9Z3w0YycR2D2xLq3ASvBL6DDMw7X0qTROC6 BTIk9v8/dbSBWCBzr6VHKFykv3mGTqv4rKjpSgMl/rdiOAbOCgaxRMZFdh/kZVhGEbmj3o0/FYlip zKDSvqF2Hk1SdIj9d6+Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qCGHJ-00HXeC-0m; Thu, 22 Jun 2023 09:06:57 +0000 Received: from relay2-d.mail.gandi.net ([217.70.183.194]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qCGH2-00HXYi-1j for linux-arm-kernel@lists.infradead.org; Thu, 22 Jun 2023 09:06:43 +0000 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 , 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230622_020640_840755_84988199 X-CRM114-Status: GOOD ( 13.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Samuel Holland , Chen-Yu Tsai , Jernej Skrabec , Tudor Ambarus , Thomas Petazzoni , Miquel Raynal , Claudiu Beznea , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 Acked-by: Ryan Wanner --- 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)