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coresight: sysfs: Use source's path pointer for path control

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Since the path pointer is stored in the source's structure, retrieve it
directly when disabling the path.

As a result, the global variables used for caching path pointers are no
longer needed. Remove them to simplify the code.

Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-22-f88c4a3ecfe9@arm.com
This commit is contained in:
Leo Yan 2026-05-15 21:08:29 +01:00 committed by Suzuki K Poulose
parent bc99077507
commit a2e91258e8
1 changed files with 9 additions and 73 deletions
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82
drivers/hwtracing/coresight/coresight-sysfs.c
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@ -5,26 +5,12 @@
*/
#include <linux/device.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/property.h>
#include "coresight-priv.h"
#include "coresight-trace-id.h"
/*
* Use IDR to map the hash of the source's device name
* to the pointer of path for the source. The idr is for
* the sources which aren't associated with CPU.
*/
static DEFINE_IDR(path_idr);
/*
* 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 coresight_path *, tracer_path);
ssize_t coresight_simple_show_pair(struct device *_dev,
struct device_attribute *attr, char *buf)
{
@ -167,11 +153,10 @@ static int coresight_validate_source_sysfs(struct coresight_device *csdev,
int coresight_enable_sysfs(struct coresight_device *csdev)
{
int cpu, ret = 0;
int ret = 0;
struct coresight_device *sink;
struct coresight_path *path;
enum coresight_dev_subtype_source subtype;
u32 hash;
subtype = csdev->subtype.source_subtype;
@ -223,37 +208,6 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
if (ret)
goto err_source;
switch (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 = csdev->cpu;
per_cpu(tracer_path, cpu) = path;
break;
case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
case CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM:
case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
/*
* Use the hash of source's device name as ID
* and map the ID to the pointer of the path.
*/
hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
ret = idr_alloc_u32(&path_idr, path, &hash, hash, GFP_KERNEL);
if (ret) {
coresight_disable_source_sysfs(csdev, NULL);
goto err_source;
}
break;
default:
/* We can't be here */
break;
}
out:
mutex_unlock(&coresight_mutex);
return ret;
@ -269,9 +223,8 @@ EXPORT_SYMBOL_GPL(coresight_enable_sysfs);
void coresight_disable_sysfs(struct coresight_device *csdev)
{
int cpu, ret;
struct coresight_path *path = NULL;
u32 hash;
struct coresight_path *path;
int ret;
mutex_lock(&coresight_mutex);
@ -279,32 +232,15 @@ void coresight_disable_sysfs(struct coresight_device *csdev)
if (ret)
goto out;
/*
* coresight_disable_source_sysfs() clears the 'csdev->path' pointer
* when disabling the source. Retrieve the path pointer here.
*/
path = csdev->path;
if (!coresight_disable_source_sysfs(csdev, NULL))
goto out;
switch (csdev->subtype.source_subtype) {
case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
cpu = csdev->cpu;
path = per_cpu(tracer_path, cpu);
per_cpu(tracer_path, cpu) = NULL;
break;
case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
case CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM:
case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
/* Find the path by the hash. */
path = idr_find(&path_idr, hash);
if (path == NULL) {
pr_err("Path is not found for %s\n", dev_name(&csdev->dev));
goto out;
}
idr_remove(&path_idr, hash);
break;
default:
/* We can't be here */
break;
}
coresight_disable_path(path);
coresight_release_path(path);