From: Neil Armstrong <narmstrong@baylibre.com>
To: khilman@baylibre.com
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Neil Armstrong <narmstrong@baylibre.com>
Subject: [PATCH 1/2] soc: amlogic: meson-clk-measure: protect measure with a mutex
Date: Mon, 29 Jul 2019 15:02:17 +0200 [thread overview]
Message-ID: <20190729130218.6635-2-narmstrong@baylibre.com> (raw)
In-Reply-To: <20190729130218.6635-1-narmstrong@baylibre.com>
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>
---
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;
--
2.22.0
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next prev parent reply other threads:[~2019-07-29 13:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 13:02 [PATCH 0/2] soc: amlogic: meson-clk-measure: g12a/b DVFS support Neil Armstrong
2019-07-29 13:02 ` Neil Armstrong [this message]
2019-07-29 13:02 ` [PATCH 2/2] soc: amlogic: meson-clk-measure: add G12B second cluster cpu clk Neil Armstrong
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