[PATCH V6 17/26] coresight: adding operation mode for sink->enable()

Mathieu Poirier
2015-12-03T21:10:43Z

Adding an operation mode to sink->enable() API in order
to prevent simultaneous access from different callers.

TPIU and TMC won't be supplemented with the AUX area
API immediately and as such ignore the new mode.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
drivers/hwtracing/coresight/coresight-etb10.c | 31 +++++++++++++++++++++------
drivers/hwtracing/coresight/coresight-priv.h | 2 +-
drivers/hwtracing/coresight/coresight-tmc.c | 2 +-
drivers/hwtracing/coresight/coresight-tpiu.c | 2 +-
drivers/hwtracing/coresight/coresight.c | 10 ++++-----
include/linux/coresight.h | 2 +-
6 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 09e306361e4f..dc4d707b28aa 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -73,9 +73,9 @@
* @miscdev: specifics to handle "/dev/xyz.etb" entry.
* @spinlock: only one at a time pls.
* @reading: synchronise user space access to etb buffer.
+ * @mode: this ETB is being used.
* @buf: area of memory where ETB buffer content gets sent.
* @buffer_depth: size of @buf.
- * @enable: this ETB is being used.
* @trigger_cntr: amount of words to store after a trigger.
*/
struct etb_drvdata {
@@ -86,9 +86,9 @@ struct etb_drvdata {
struct miscdevice miscdev;
spinlock_t spinlock;
local_t reading;
+ local_t mode;
u8 *buf;
u32 buffer_depth;
- bool enable;
u32 trigger_cntr;
};

@@ -133,18 +133,34 @@ static void etb_enable_hw(struct etb_drvdata *drvdata)
CS_LOCK(drvdata->base);
}

-static int etb_enable(struct coresight_device *csdev)
+static int etb_enable(struct coresight_device *csdev, u32 mode)
{
- struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+ u32 val;
unsigned long flags;
+ struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ val = local_cmpxchg(&drvdata->mode,
+ CS_MODE_DISABLED, mode);
+ /*
+ * When accessing from Perf, a HW buffer can be handled
+ * by a single trace entity. In sysFS mode many tracers
+ * can be logging to the same HW buffer.
+ */
+ if (val == CS_MODE_PERF)
+ return -EBUSY;
+
+ /* Nothing to do, the tracer is already enabled. */
+ if (val == CS_MODE_SYSFS)
+ goto out;

spin_lock_irqsave(&drvdata->spinlock, flags);
etb_enable_hw(drvdata);
- drvdata->enable = true;
spin_unlock_irqrestore(&drvdata->spinlock, flags);

+out:
dev_info(drvdata->dev, "ETB enabled\n");
return 0;
+
}

static void etb_disable_hw(struct etb_drvdata *drvdata)
@@ -243,9 +259,10 @@ static void etb_disable(struct coresight_device *csdev)
spin_lock_irqsave(&drvdata->spinlock, flags);
etb_disable_hw(drvdata);
etb_dump_hw(drvdata);
- drvdata->enable = false;
spin_unlock_irqrestore(&drvdata->spinlock, flags);

+ local_set(&drvdata->mode, CS_MODE_DISABLED);
+
dev_info(drvdata->dev, "ETB disabled\n");
}

@@ -263,7 +280,7 @@ static void etb_dump(struct etb_drvdata *drvdata)
unsigned long flags;

spin_lock_irqsave(&drvdata->spinlock, flags);
- if (drvdata->enable) {
+ if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
etb_disable_hw(drvdata);
etb_dump_hw(drvdata);
etb_enable_hw(drvdata);
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 932f34a84d96..333eddaed339 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -62,7 +62,7 @@ static inline void CS_UNLOCK(void __iomem *addr)
}

void coresight_disable_path(struct list_head *path);
-int coresight_enable_path(struct list_head *path);
+int coresight_enable_path(struct list_head *path, u32 mode);
struct coresight_device *coresight_get_sink(struct list_head *path);
struct list_head *coresight_build_path(struct coresight_device *csdev);
void coresight_release_path(struct list_head *path);
diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 5e2a71767870..d7e83da7a621 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -265,7 +265,7 @@ static int tmc_enable(struct tmc_drvdata *drvdata, enum tmc_mode mode)
return 0;
}

-static int tmc_enable_sink(struct coresight_device *csdev)
+static int tmc_enable_sink(struct coresight_device *csdev, u32 mode)
{
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
index e19b86e61c38..0a09135382f6 100644
--- a/drivers/hwtracing/coresight/coresight-tpiu.c
+++ b/drivers/hwtracing/coresight/coresight-tpiu.c
@@ -70,7 +70,7 @@ static void tpiu_enable_hw(struct tpiu_drvdata *drvdata)
CS_LOCK(drvdata->base);
}

-static int tpiu_enable(struct coresight_device *csdev)
+static int tpiu_enable(struct coresight_device *csdev, u32 mode)
{
struct tpiu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index c02da2edfd80..428bcd446eaf 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -121,13 +121,13 @@ static int coresight_find_link_outport(struct coresight_device *csdev,
return 0;
}

-static int coresight_enable_sink(struct coresight_device *csdev)
+static int coresight_enable_sink(struct coresight_device *csdev, u32 mode)
{
int ret;

if (!csdev->enable) {
if (sink_ops(csdev)->enable) {
- ret = sink_ops(csdev)->enable(csdev);
+ ret = sink_ops(csdev)->enable(csdev, mode);
if (ret)
return ret;
}
@@ -283,7 +283,7 @@ void coresight_disable_path(struct list_head *path)
}
}

-int coresight_enable_path(struct list_head *path)
+int coresight_enable_path(struct list_head *path, u32 mode)
{

int ret = 0;
@@ -296,7 +296,7 @@ int coresight_enable_path(struct list_head *path)
switch (csdev->type) {
case CORESIGHT_DEV_TYPE_SINK:
case CORESIGHT_DEV_TYPE_LINKSINK:
- ret = coresight_enable_sink(csdev);
+ ret = coresight_enable_sink(csdev, mode);
if (ret)
goto err;
break;
@@ -454,7 +454,7 @@ int coresight_enable(struct coresight_device *csdev)
goto out;
}

- ret = coresight_enable_path(path);
+ ret = coresight_enable_path(path, CS_MODE_SYSFS);
if (ret)
goto err_path;

diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index da242dfebdbd..2b94994d2c02 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -185,7 +185,7 @@ struct coresight_device {
* @disable: disables the sink.
*/
struct coresight_ops_sink {
- int (*enable)(struct coresight_device *csdev);
+ int (*enable)(struct coresight_device *csdev, u32 mode);
void (*disable)(struct coresight_device *csdev);
};

--
2.1.4