From 3a3ca923be330c3a8b0f391d8e92040f4987eb21 Mon Sep 17 00:00:00 2001 From: Mohammed Shafi Shajakhan Date: Mon, 18 Jun 2012 13:13:30 +0530 Subject: [PATCH] ath9k_hw: avoid possible infinite loop in ar9003_get_pll_sqsum_dvc 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: Greg Kroah-Hartman --- 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 7c2f06ed7a1d..05320b9888b8 100644 --- a/drivers/net/wireless/ath/ath9k/hw.c +++ b/drivers/net/wireless/ath/ath9k/hw.c @@ -682,13 +682,25 @@ 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); -- 2.34.1