Commit f18e3c6b authored Jun 18, 2012 by Mohammed Shafi Shajakhan Committed by John W. Linville Jun 20, 2012

ath9k_hw: avoid possible infinite loop in ar9003_get_pll_sqsum_dvc

"ath9k: Fix softlockup in AR9485" with commit id
64bc1239 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: stable@vger.kernel.org
Cc: Rolf Offermanns <rolf.offermanns@gmx.net>
Cc: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Cc: Senthil Balasubramanian <senthilb@qca.qualcomm.com>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

parent a859e4d6

drivers/net/wireless/ath/ath9k/hw.c

+13 −1

Original line number	Diff line number	Diff line
		@@ -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);