From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756192Ab2GASVI (ORCPT ); Sun, 1 Jul 2012 14:21:08 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:47054 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932414Ab2GASQn (ORCPT ); Sun, 1 Jul 2012 14:16:43 -0400 Message-Id: <20120701172010.952716529@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 01 Jul 2012 18:20:36 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Mohammed Shafi Shajakhan , Rolf Offermanns , Sujith Manoharan , Senthil Balasubramanian , "John W. Linville" Subject: [ 30/48] ath9k_hw: avoid possible infinite loop in ar9003_get_pll_sqsum_dvc In-Reply-To: <20120701172006.535271340@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mohammed Shafi Shajakhan commit f18e3c6b67f448ec47b3a5b242789bd3d5644879 upstream. "ath9k: Fix softlockup in AR9485" with commit id 64bc1239c790e051ff677e023435d770d2ffa174 fixed the reported issue, yet its better to avoid the possible infinite loop in ar9003_get_pll_sqsum_dvc by having a timeout as suggested by ath9k maintainers. http://www.spinics.net/lists/linux-wireless/msg92126.html. Based on my testing PLL's locking measurement is done in ~200us (2 iterations). Cc: Rolf Offermanns Cc: Sujith Manoharan Cc: Senthil Balasubramanian Signed-off-by: Mohammed Shafi Shajakhan Signed-off-by: John W. Linville Signed-off-by: Ben Hutchings --- drivers/net/wireless/ath/ath9k/hw.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c index 7db1890..1c68e56 100644 --- a/drivers/net/wireless/ath/ath9k/hw.c +++ b/drivers/net/wireless/ath/ath9k/hw.c @@ -784,13 +784,25 @@ static void ath9k_hw_init_qos(struct ath_hw *ah) u32 ar9003_get_pll_sqsum_dvc(struct ath_hw *ah) { + struct ath_common *common = ath9k_hw_common(ah); + int i = 0; + REG_CLR_BIT(ah, PLL3, PLL3_DO_MEAS_MASK); udelay(100); REG_SET_BIT(ah, PLL3, PLL3_DO_MEAS_MASK); - while ((REG_READ(ah, PLL4) & PLL4_MEAS_DONE) == 0) + while ((REG_READ(ah, PLL4) & PLL4_MEAS_DONE) == 0) { + udelay(100); + if (WARN_ON_ONCE(i >= 100)) { + ath_err(common, "PLL4 meaurement not done\n"); + break; + } + + i++; + } + return (REG_READ(ah, PLL3) & SQSUM_DVC_MASK) >> 3; } EXPORT_SYMBOL(ar9003_get_pll_sqsum_dvc);