* [PATCH AUTOSEL 5.2 035/185] soc: amlogic: meson-clk-measure: protect measure with a mutex
[not found] <20190922184924.32534-1-sashal@kernel.org>
@ 2019-09-22 18:46 ` Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2019-09-22 18:46 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Martin Blumenstingl, Kevin Hilman, linux-amlogic, Sasha Levin,
Neil Armstrong
From: Neil Armstrong <narmstrong@baylibre.com>
[ Upstream commit 3a760d986568b67d1f8411dab64608075817b90d ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 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;
--
2.20.1
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