From: Neil Armstrong <narmstrong@baylibre.com>
Date: Mon, 29 Jul 2019 13:02:17 +0000 (+0200)
Subject: soc: amlogic: meson-clk-measure: protect measure with a mutex
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3a760d986568b67d1f8411dab64608075817b90d;p=linux.git

soc: amlogic: meson-clk-measure: protect measure with a mutex

In order to protect clock measuring when multiple process asks for
a measure, protect the main measure function with mutexes.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
---

diff --git a/drivers/soc/amlogic/meson-clk-measure.c b/drivers/soc/amlogic/meson-clk-measure.c
index 19d4cbc93a17a..c470e24f1dfa6 100644
--- a/drivers/soc/amlogic/meson-clk-measure.c
+++ b/drivers/soc/amlogic/meson-clk-measure.c
@@ -11,6 +11,8 @@
 #include <linux/debugfs.h>
 #include <linux/regmap.h>
 
+static DEFINE_MUTEX(measure_lock);
+
 #define MSR_CLK_DUTY		0x0
 #define MSR_CLK_REG0		0x4
 #define MSR_CLK_REG1		0x8
@@ -360,6 +362,10 @@ static int meson_measure_id(struct meson_msr_id *clk_msr_id,
 	unsigned int val;
 	int ret;
 
+	ret = mutex_lock_interruptible(&measure_lock);
+	if (ret)
+		return ret;
+
 	regmap_write(priv->regmap, MSR_CLK_REG0, 0);
 
 	/* Set measurement duration */
@@ -377,8 +383,10 @@ static int meson_measure_id(struct meson_msr_id *clk_msr_id,
 
 	ret = regmap_read_poll_timeout(priv->regmap, MSR_CLK_REG0,
 				       val, !(val & MSR_BUSY), 10, 10000);
-	if (ret)
+	if (ret) {
+		mutex_unlock(&measure_lock);
 		return ret;
+	}
 
 	/* Disable */
 	regmap_update_bits(priv->regmap, MSR_CLK_REG0, MSR_ENABLE, 0);
@@ -386,6 +394,8 @@ static int meson_measure_id(struct meson_msr_id *clk_msr_id,
 	/* Get the value in multiple of gate time counts */
 	regmap_read(priv->regmap, MSR_CLK_REG2, &val);
 
+	mutex_unlock(&measure_lock);
+
 	if (val >= MSR_VAL_MASK)
 		return -EINVAL;