From: James Clark <james.clark@xxxxxxx>
[ Upstream commit 3244fb6dbbf1ffc114cdf382cc167bdd8c18088a ]
Writing 0 to the enable control repeatedly results in a negative value
for enable_req_count. After this, writing 1 to the enable control
appears to not work until the count returns to positive.
Change it so that it's impossible for enable_req_count to be < 0.
Return an error to indicate that the disable request was invalid.
Fixes: 835d722ba10a ("coresight: cti: Initial CoreSight CTI Driver")
Tested-by: Jinlong Mao <quic_jinlmao@xxxxxxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxx>
Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Link: https://lore.kernel.org/r/20230110110736.2709917-2-james.clark@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/hwtracing/coresight/coresight-cti-core.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index d2cf4f4848e1b..838872f2484d3 100644
--- a/drivers/hwtracing/coresight/coresight-cti-core.c
+++ b/drivers/hwtracing/coresight/coresight-cti-core.c
@@ -151,9 +151,16 @@ static int cti_disable_hw(struct cti_drvdata *drvdata)
{
struct cti_config *config = &drvdata->config;
struct coresight_device *csdev = drvdata->csdev;
+ int ret = 0;
spin_lock(&drvdata->spinlock);
+ /* don't allow negative refcounts, return an error */
+ if (!atomic_read(&drvdata->config.enable_req_count)) {
+ ret = -EINVAL;
+ goto cti_not_disabled;
+ }
+
/* check refcount - disable on 0 */
if (atomic_dec_return(&drvdata->config.enable_req_count) > 0)
goto cti_not_disabled;
@@ -171,12 +178,12 @@ static int cti_disable_hw(struct cti_drvdata *drvdata)
coresight_disclaim_device_unlocked(csdev);
CS_LOCK(drvdata->base);
spin_unlock(&drvdata->spinlock);
- return 0;
+ return ret;
/* not disabled this call */
cti_not_disabled:
spin_unlock(&drvdata->spinlock);
- return 0;
+ return ret;
}
void cti_write_single_reg(struct cti_drvdata *drvdata, int offset, u32 value)
--
2.39.2
