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coresight: adding path for STM device 

>From a core framework point of view an STM device is a source that is
treated the same way as any other tracers.  Unlike tracers though STM
devices are not associated with a CPU.  As such it doesn't make sense
to associate the path from an STM device to its sink with a per-cpu
variable as it is done for tracers.

This patch simply adds another global variable to keep STM paths and the
processing in coresight_enable/disable() is updated to deal with STM
devices properly.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathieu Poirier 2016-05-03 11:33:38 -06:00 committed by Greg Kroah-Hartman
parent 8e996a2874
commit a685d68328
1 changed files with 82 additions and 24 deletions
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106
drivers/hwtracing/coresight/coresight.c
View File

@ -43,7 +43,15 @@ struct coresight_node {
* When operating Coresight drivers from the sysFS interface, only a single
* path can exist from a tracer (associated to a CPU) to a sink.
*/
static DEFINE_PER_CPU(struct list_head *, sysfs_path);
static DEFINE_PER_CPU(struct list_head *, tracer_path);
/*
* As of this writing only a single STM can be found in CS topologies. Since
* there is no way to know if we'll ever see more and what kind of
* configuration they will enact, for the time being only define a single path
* for STM.
*/
static struct list_head *stm_path;
static int coresight_id_match(struct device *dev, void *data)
{
@ -432,18 +440,45 @@ void coresight_release_path(struct list_head *path)
path = NULL;
}
/** coresight_validate_source - make sure a source has the right credentials
* @csdev: the device structure for a source.
* @function: the function this was called from.
*
* Assumes the coresight_mutex is held.
*/
static int coresight_validate_source(struct coresight_device *csdev,
const char *function)
{
u32 type, subtype;
type = csdev->type;
subtype = csdev->subtype.source_subtype;
if (type != CORESIGHT_DEV_TYPE_SOURCE) {
dev_err(&csdev->dev, "wrong device type in %s\n", function);
return -EINVAL;
}
if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE) {
dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
return -EINVAL;
}
return 0;
}
int coresight_enable(struct coresight_device *csdev)
{
int ret = 0;
int cpu;
int cpu, ret = 0;
struct list_head *path;
mutex_lock(&coresight_mutex);
if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
ret = -EINVAL;
dev_err(&csdev->dev, "wrong device type in %s\n", __func__);
ret = coresight_validate_source(csdev, __func__);
if (ret)
goto out;
}
if (csdev->enable)
goto out;
@ -461,15 +496,25 @@ int coresight_enable(struct coresight_device *csdev)
if (ret)
goto err_source;
/*
* When working from sysFS it is important to keep track
* of the paths that were created so that they can be
* undone in 'coresight_disable()'. Since there can only
* be a single session per tracer (when working from sysFS)
* a per-cpu variable will do just fine.
*/
cpu = source_ops(csdev)->cpu_id(csdev);
per_cpu(sysfs_path, cpu) = path;
switch (csdev->subtype.source_subtype) {
case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
/*
* When working from sysFS it is important to keep track
* of the paths that were created so that they can be
* undone in 'coresight_disable()'. Since there can only
* be a single session per tracer (when working from sysFS)
* a per-cpu variable will do just fine.
*/
cpu = source_ops(csdev)->cpu_id(csdev);
per_cpu(tracer_path, cpu) = path;
break;
case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
stm_path = path;
break;
default:
/* We can't be here */
break;
}
out:
mutex_unlock(&coresight_mutex);
@ -486,23 +531,36 @@ EXPORT_SYMBOL_GPL(coresight_enable);
void coresight_disable(struct coresight_device *csdev)
{
int cpu;
struct list_head *path;
int cpu, ret;
struct list_head *path = NULL;
mutex_lock(&coresight_mutex);
if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
dev_err(&csdev->dev, "wrong device type in %s\n", __func__);
ret = coresight_validate_source(csdev, __func__);
if (ret)
goto out;
}
if (!csdev->enable)
goto out;
cpu = source_ops(csdev)->cpu_id(csdev);
path = per_cpu(sysfs_path, cpu);
switch (csdev->subtype.source_subtype) {
case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
cpu = source_ops(csdev)->cpu_id(csdev);
path = per_cpu(tracer_path, cpu);
per_cpu(tracer_path, cpu) = NULL;
break;
case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
path = stm_path;
stm_path = NULL;
break;
default:
/* We can't be here */
break;
}
coresight_disable_source(csdev);
coresight_disable_path(path);
coresight_release_path(path);
per_cpu(sysfs_path, cpu) = NULL;
out:
mutex_unlock(&coresight_mutex);