2019-07-01 09:15:54

by Neil Armstrong

Subject: [RFC/RFT v3 05/14] 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 <[email protected]>
Signed-off-by: Neil Armstrong <[email protected]>
---
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

2019-07-03 00:37:05

by Martin Blumenstingl

Subject: Re: [RFC/RFT v3 05/14] soc: amlogic: meson-clk-measure: protect measure with a mutex

Hi Neil,

On Mon, Jul 1, 2019 at 11:13 AM Neil Armstrong <[email protected]> wrote:
>
> In order to protect clock measuring when multiple process asks for
> a measure, protect the main measure function with mutexes.
>
> Reviewed-by: Kevin Hilman <[email protected]>
> Signed-off-by: Neil Armstrong <[email protected]>
> ---
> 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);
I wonder if that should be part of struct meson_msr for consistency reasons

apart from that:
Reviewed-by: Martin Blumenstingl <[email protected]>