From patchwork Mon Jun 19 15:53:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 13284754 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 9A87EEB64D9 for ; Mon, 19 Jun 2023 15:54:35 +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=dc6/g2cb8NMOTKpbDW4D/7YfLPRvg20OX6NFnSsSbBE=; b=RH+WEwN7snvXmW 2iHpVKWo9qHZPb6MSTfMTQAxv1fmaP7uay8GQxtxxxXUn00/pxGWWgCjTR+CGcY9X8br8nJjrIMNn rx1b3I81AXIc+MsCL5/gIw/RBsMJyzDZ3ODMlo9Wj+VLYztCgTToA151wlRwEF8Tv4cnTTufX9qRA 89dTn2DXv/TIXfm60VJRvred+4u5EuFh1Ry9hWO9ER7vfxy0GDed6t5fE91aUNlbHifxCFOXbdHS3 zME1SmF4lg89gQ4sMnMo9+SfwJdJsXMlc2+W4JeyXVgQJDWp/a674hGDtC0esuv/shUi2/S4BTlSY Ht+Czi+RnJHK7gYdmBmg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qBHCo-008qog-0G; Mon, 19 Jun 2023 15:54:14 +0000 Received: from relay8-d.mail.gandi.net ([217.70.183.201]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qBHCZ-008qkb-0B for linux-arm-kernel@lists.infradead.org; Mon, 19 Jun 2023 15:54:01 +0000 X-GND-Sasl: miquel.raynal@bootlin.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1687190036; 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=RVl7mcQ2hRFnAGAiMjDiHg2vEcGhnErk/G4vbtij5nQ=; b=N/oKqopIgRPFhHRhcoBJVpXbyRInOqOPNYpdFtIt7iiIu7FsfgS6nrJslb5ep21xvzxikp QRjeYieP5o1uuHdfbflDHwPDQZ/HB7FiFqJdgBkTKKbwDLVC/DV16h1WXdaOj9Ds5SqntA OSW0l9A7GW4PlT2WvBpHNuFTL8W86gbwuwZGINrGJYbVfiBFbJDkqQg+NbKU0u/tPptpPT PfMlDupDsXVRmodLobC5m9JUngqhi8KOAycA04P/5vqbGygVpP5NrC1o7fIQRB2TiDhcEM emiH9h0JWRcrRMCS9T4j0HWDvlKPFojnAibVCGHYV5CNxzjr9Me+ozd1XHWH5w== 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 X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com Received: by mail.gandi.net (Postfix) with ESMTPSA id 3EC2A1BF203; Mon, 19 Jun 2023 15:53:55 +0000 (UTC) From: Miquel Raynal To: Mark Brown , Subject: [PATCH v2 2/3] spi: atmel: Prevent false timeouts on long transfers Date: Mon, 19 Jun 2023 17:53:48 +0200 Message-Id: <20230619155349.3118420-3-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230619155349.3118420-1-miquel.raynal@bootlin.com> References: <20230619155349.3118420-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230619_085359_359104_F9CB2310 X-CRM114-Status: GOOD ( 14.34 ) 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: Alexandre Belloni , Samuel Holland , Chen-Yu Tsai , Jernej Skrabec , Tudor Ambarus , Thomas Petazzoni , Miquel Raynal , linux-sunxi@lists.linux.dev, 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 --- 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 c4f22d50dba5..d1743817a5da 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_master *master, struct atmel_spi_device *asd; int timeout; int ret; - unsigned long dma_timeout; + unsigned int dma_timeout; + long ret_timeout; as = spi_master_get_devdata(master); @@ -1333,11 +1335,13 @@ static int atmel_spi_one_transfer(struct spi_master *master, 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(master, 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)