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: 13288806 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 CFD49EB64DA for ; Thu, 22 Jun 2023 09:07:15 +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=nn7jzvjZXgSNHMP1VOAw1kMWhqQCYnx5uSa/pv5CNg0=; b=sPFLxpFsk34GvL q5yz16il0e5shnmeRzE6D7R5nC5LPtgn4nTCdaYYLoGIUSGBxKpxTp9EvU3sB0rB8JqRvXM8ZD0D1 Wqmp/CcG4jYnLPKnPcIQA6/fUdDqfzs/GP1wp2MP/QdmWNOQOExi7a39PRITKHzz+O3cCg+VxGUk2 6YQHzdX0nIteXrD4FU1PrXAtfw7GjG2AkNACkpiOi0QF9sCuiCKRx3rawXcQHhmxJxOZ8V+D28mTw mvzPoMlgd3KoMgqrUAUNS5DS3brAnqO3XDm09UAvaY96+9/xsErWzVvA/4Nv0UsjPBEWWbpyJwfDn m3pbKnhhzjsjRCZoHKjQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qCGH6-00HXau-1F; Thu, 22 Jun 2023 09:06:44 +0000 Received: from relay2-d.mail.gandi.net ([2001:4b98:dc4:8::222]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qCGH2-00HXYa-1n for linux-arm-kernel@lists.infradead.org; Thu, 22 Jun 2023 09:06:42 +0000 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 , 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230622_020640_753125_3B1AD305 X-CRM114-Status: GOOD ( 12.48 ) 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 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 */