From patchwork Thu Dec 29 10:46:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Ivan Bornyakov X-Patchwork-Id: 13083426 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 635A7C3DA7D for ; Thu, 29 Dec 2022 10:51:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233170AbiL2KtY (ORCPT ); Thu, 29 Dec 2022 05:49:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233207AbiL2KtL (ORCPT ); Thu, 29 Dec 2022 05:49:11 -0500 Received: from mail.pr-group.ru (mail.pr-group.ru [178.18.215.3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D033C12AD7; Thu, 29 Dec 2022 02:49:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=metrotek.ru; s=mail; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=die6ad0vYZHCb65m5Hf63s1td7LWEbm4RdnqouvV7iI=; b=WxPV0/QYen/zKibDP/wLAlVvTkEkr5ICx5bL6tXz656lTRn/ZEWTvExFV1x1ZKdyvp1yNoepPuWQt vYZ5fNBsmoNqKcw1apIdQfVE24Qt9YJm085ZegeAhOCWFAltNXk8HCS/TpSJEzuIbIFuUcWW1Ttcq1 OZGhyt9roBeEZgQCDJkgSrmyr6Yusl4hsJ3QaIKYrAH9GRUqyIPhWtL0T2/ahrPaCceRxJD711We24 93nTA5Zy9fNNpDNUZBKVT0bP2Po9hqG4yEGuCqy/qCbPVFhg9sjLhiH5Nk6jyETG9IuaO5M/9cbVwc 6XQ2bcLcqFzlg4TjCDDXCafI8KnoVow== X-Kerio-Anti-Spam: Build: [Engines: 2.16.5.1460, Stamp: 3], Multi: [Enabled, t: (0.000011,0.013400)], BW: [Enabled, t: (0.000022,0.000001)], RTDA: [Enabled, t: (0.128619), Hit: No, Details: v2.42.0; Id: 15.52k5u3.1glenvb0e.j55e; mclb], total: 0(700) X-Footer: bWV0cm90ZWsucnU= Received: from h-e2.ddg ([85.143.252.66]) (authenticated user i.bornyakov@metrotek.ru) by mail.pr-group.ru with ESMTPSA (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256 bits)); Thu, 29 Dec 2022 13:48:44 +0300 From: Ivan Bornyakov To: linux-fpga@vger.kernel.org Cc: Ivan Bornyakov , Conor Dooley , Moritz Fischer , Wu Hao , Xu Yilun , Tom Rix , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-kernel@vger.kernel.org, system@metrotek.ru Subject: [PATCH v4 2/3] fpga: microchip-spi: rewrite status polling in a time measurable way Date: Thu, 29 Dec 2022 13:46:03 +0300 Message-Id: <20221229104604.2496-3-i.bornyakov@metrotek.ru> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221229104604.2496-1-i.bornyakov@metrotek.ru> References: <20221229104604.2496-1-i.bornyakov@metrotek.ru> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fpga@vger.kernel.org Original busy loop with retries count in mpf_poll_status() is not too reliable, as it takes different times on different systems. Replace it with read_poll_timeout() macro. While at it, fix polling stop condition to met function's original intention declared in the comment. The issue with original polling stop condition is that it stops if any of mask bits is set, while intention was to stop if all mask bits is set. This was not noticible because only MPF_STATUS_READY is passed as mask argument and it is BIT(1). Fixes: 5f8d4a900830 ("fpga: microchip-spi: add Microchip MPF FPGA manager") Signed-off-by: Ivan Bornyakov Reviewed-by: Ilpo Järvinen Acked-by: Conor Dooley Acked-by: Xu Yilun --- drivers/fpga/microchip-spi.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c index e72fedd93a27..995b1964e0fe 100644 --- a/drivers/fpga/microchip-spi.c +++ b/drivers/fpga/microchip-spi.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -33,7 +34,7 @@ #define MPF_BITS_PER_COMPONENT_SIZE 22 -#define MPF_STATUS_POLL_RETRIES 10000 +#define MPF_STATUS_POLL_TIMEOUT (2 * USEC_PER_SEC) #define MPF_STATUS_BUSY BIT(0) #define MPF_STATUS_READY BIT(1) #define MPF_STATUS_SPI_VIOLATION BIT(2) @@ -194,24 +195,25 @@ static int mpf_ops_parse_header(struct fpga_manager *mgr, return 0; } -/* Poll HW status until busy bit is cleared and mask bits are set. */ static int mpf_poll_status(struct mpf_priv *priv, u8 mask) { - int status, retries = MPF_STATUS_POLL_RETRIES; + int ret, status; - while (retries--) { - status = mpf_read_status(priv); - if (status < 0) - return status; - - if (status & MPF_STATUS_BUSY) - continue; - - if (!mask || (status & mask)) - return status; - } + /* + * Busy poll HW status. Polling stops if any of the following + * conditions are met: + * - timeout is reached + * - mpf_read_status() returns an error + * - busy bit is cleared AND mask bits are set + */ + ret = read_poll_timeout(mpf_read_status, status, + (status < 0) || + ((status & (MPF_STATUS_BUSY | mask)) == mask), + 0, MPF_STATUS_POLL_TIMEOUT, false, priv); + if (ret < 0) + return ret; - return -EBUSY; + return status; } static int mpf_spi_write(struct mpf_priv *priv, const void *buf, size_t buf_size)