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Subject[RFC/RFT 05/14] soc: amlogic: meson-clk-measure: protect measure with a mutex
Date
In order to protect clock measuring when multiple process asks for
a mesure, protect the main measure function with mutexes.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
drivers/soc/amlogic/meson-clk-measure.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/amlogic/meson-clk-measure.c b/drivers/soc/amlogic/meson-clk-measure.c
index 19d4cbc93a17..c470e24f1dfa 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;

--
2.21.0
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