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;