[RFC/RFT v3 05/14] soc: amlogic: meson-clk-measure: protect measure with a mutex
From: Neil Armstrong <hidden>
Date: 2019-07-01 09:14:11
Also in:
linux-amlogic, linux-clk, linux-gpio, lkml
Subsystem:
arm/amlogic meson soc support, the rest · Maintainers:
Neil Armstrong, Kevin Hilman, Linus Torvalds
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> Signed-off-by: Neil Armstrong <redacted> --- 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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