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Message-Id: <1459997479-19431-3-git-send-email-zhang.chunyan@linaro.org>
Date: Thu, 7 Apr 2016 10:51:17 +0800
From: Chunyan Zhang <zhang.chunyan@...aro.org>
To: mathieu.poirier@...aro.org, alexander.shishkin@...ux.intel.com
Cc: mike.leach@....com, Michael.Williams@....com, al.grant@....com,
tor@...com, nicolas.guion@...com, pratikp@...eaurora.org,
zhang.lyra@...il.com, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-api@...r.kernel.org,
linux-doc@...r.kernel.org
Subject: [PATCH V5 2/4] coresight: adding path for STM device
From: Mathieu Poirier <mathieu.poirier@...aro.org>
>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@...aro.org>
Signed-off-by: Chunyan Zhang <zhang.chunyan@...aro.org>
---
drivers/hwtracing/coresight/coresight.c | 106 ++++++++++++++++++++++++--------
1 file changed, 82 insertions(+), 24 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 2ea5961..6c80663 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -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);
--
1.9.1
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