From patchwork Thu Jun 22 09:06:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 697177 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 17BCEEB64D8 for ; Thu, 22 Jun 2023 09:16:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232271AbjFVJQx (ORCPT ); Thu, 22 Jun 2023 05:16:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232357AbjFVJOv (ORCPT ); Thu, 22 Jun 2023 05:14:51 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFE2A5254 for ; Thu, 22 Jun 2023 02:06:38 -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=1687424797; 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=PhIQmvwCqc8f2ldfvdDwrf5zFPY90uFTbI6lO/wBafo=; b=i6LxrBfmEyVAED6//TqtsJRl9Yyr2HhOn49PmsrhLcVmi8MJlLOXW+RYw5jcifjLX9pbYx zk6aLfYgaTXutwDG7gHCnKso1wla9Ekx/5eQLwN0WvvBn/lOdqm1OXaJWRzLxPriHjNAwy capbdvwCrPYuUcgjDOaHEXwJYdyLdGIonpr8Rwq4hNyrlU1RouwWea8Y0QLRj/VNR9h3tj iaNn/S0D2dT/UOIQrpBPopYS3N2yypjfa2tU4ReRWOYC6FSWJgHzhteqlALF93cdovy2BC UIAg8Y5c0csX0I7G8UFtE4pdHruF2PdfGDtWXk4KWs4ObLg1MFTCMFwegIZGgg== 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 5993640010; Thu, 22 Jun 2023 09:06:36 +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 1/3] spi: Create a helper to derive adaptive timeouts Date: Thu, 22 Jun 2023 11:06:32 +0200 Message-Id: <20230622090634.3411468-2-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 Big transfers might take a bit of time, too constraining timeouts might lead to false positives. In order to simplify the drivers work and with the goal of factorizing code in mind, let's add a helper that can be used by any spi controller driver to derive a relevant per-transfer timeout value. The logic is simple: we know how much time it would take to transfer a byte, we can easily derive the total theoretical amount of time involved for each transfer. We multiply it by two to have a bit of margin and enforce a minimum of 500ms. Suggested-by: Mark Brown Signed-off-by: Miquel Raynal --- include/linux/spi/spi.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index fbf8c0d95968..4d6636c50465 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -1186,6 +1186,23 @@ static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw) return false; } +/** + * spi_controller_xfer_timeout - Compute a suitable timeout value + * @ctlr: SPI device + * @xfer: Transfer descriptor + * + * Compute a relevant timeout value for the given transfer. We derive the time + * that it would take on a single data line and take twice this amount of time + * with a minimum of 500ms to avoid false positives on loaded systems. + * + * Returns: Transfer timeout value in milliseconds. + */ +static inline unsigned int spi_controller_xfer_timeout(struct spi_controller *ctlr, + struct spi_transfer *xfer) +{ + return max(xfer->len * 8 * 2 / (xfer->speed_hz / 1000), 500U); +} + /*---------------------------------------------------------------------------*/ /* SPI transfer replacement methods which make use of spi_res */