From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0E53C433F5 for ; Tue, 16 Nov 2021 00:59:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A35CC61B2A for ; Tue, 16 Nov 2021 00:59:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343696AbhKPBCa (ORCPT ); Mon, 15 Nov 2021 20:02:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:44628 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245750AbhKOTVI (ORCPT ); Mon, 15 Nov 2021 14:21:08 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 167CC632F6; Mon, 15 Nov 2021 18:40:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637001629; bh=8GwS4AjwiiTZMorK0iz3ID6+BH3cgVcnS/xU0obfKNM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Rrv5ROH3khd0ZDOpqkBTD0WF2pCPyhzZqsfjvOsSEkNy97XjkFwSk9jK8ROJvkJHR oAm22usZfJljPQzw1v8OrsvNIsbH5EEuVJvBwkC92ulYquaDV0BwEcQRSeaRS0rk0+ tmfPjnUrTOql7kg1Pit2KBJuStc9SnwGHqe7lhPg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ansuel Smith , Bjorn Andersson , Daniel Lezcano , Sasha Levin Subject: [PATCH 5.15 262/917] thermal/drivers/tsens: Add timeout to get_temp_tsens_valid Date: Mon, 15 Nov 2021 17:55:57 +0100 Message-Id: <20211115165437.671079522@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165428.722074685@linuxfoundation.org> References: <20211115165428.722074685@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ansuel Smith [ Upstream commit d012f9189fda0f3a1b303780ba0bbc7298d0d349 ] The function can loop and lock the system if for whatever reason the bit for the target sensor is NEVER valid. This is the case if a sensor is disabled by the factory and the valid bit is never reported as actually valid. Add a timeout check and exit if a timeout occurs. As this is a very rare condition, handle the timeout only if the first read fails. While at it also rework the function to improve readability and convert to poll_timeout generic macro. Signed-off-by: Ansuel Smith Reviewed-by: Bjorn Andersson Link: https://lore.kernel.org/r/20211007172859.583-1-ansuelsmth@gmail.com Signed-off-by: Daniel Lezcano Signed-off-by: Sasha Levin --- drivers/thermal/qcom/tsens.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c index b1162e566a707..99a8d9f3e03ca 100644 --- a/drivers/thermal/qcom/tsens.c +++ b/drivers/thermal/qcom/tsens.c @@ -603,22 +603,21 @@ int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp) int ret; /* VER_0 doesn't have VALID bit */ - if (tsens_version(priv) >= VER_0_1) { - ret = regmap_field_read(priv->rf[valid_idx], &valid); - if (ret) - return ret; - while (!valid) { - /* Valid bit is 0 for 6 AHB clock cycles. - * At 19.2MHz, 1 AHB clock is ~60ns. - * We should enter this loop very, very rarely. - */ - ndelay(400); - ret = regmap_field_read(priv->rf[valid_idx], &valid); - if (ret) - return ret; - } - } + if (tsens_version(priv) == VER_0) + goto get_temp; + + /* Valid bit is 0 for 6 AHB clock cycles. + * At 19.2MHz, 1 AHB clock is ~60ns. + * We should enter this loop very, very rarely. + * Wait 1 us since it's the min of poll_timeout macro. + * Old value was 400 ns. + */ + ret = regmap_field_read_poll_timeout(priv->rf[valid_idx], valid, + valid, 1, 20 * USEC_PER_MSEC); + if (ret) + return ret; +get_temp: /* Valid bit is set, OK to read the temperature */ *temp = tsens_hw_to_mC(s, temp_idx); -- 2.33.0