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authorJames Clark <james.clark@arm.com>2023-04-25 17:35:28 +0300
committerSuzuki K Poulose <suzuki.poulose@arm.com>2023-06-05 17:46:45 +0300
commitc45b2835e7b205783bdfe08cc98fa86a7c5eeb74 (patch)
treef3f0618020d7f85e7dd7ec499fedab16f9599d11 /drivers/hwtracing/coresight
parentd388f06aced3b9fe2fb167f48ceedf75ea7629f8 (diff)
downloadlinux-c45b2835e7b205783bdfe08cc98fa86a7c5eeb74.tar.xz
coresight: Fix loss of connection info when a module is unloaded
child_fwnode should be a read only property based on the DT or ACPI. If it's cleared on the parent device when a child is unloaded, then when the child is loaded again the connection won't be remade. child_dev should be cleared instead which signifies that the connection should be remade when the child_fwnode registers a new coresight_device. Similarly the reference count shouldn't be decremented as long as the parent device exists. The correct place to drop the reference is in coresight_release_platform_data() which is already done. Reproducible on Juno with the following steps: # load all coresight modules. $ cd /sys/bus/coresight/devices/ $ echo 1 > tmc_etr0/enable_sink $ echo 1 > etm0/enable_source # Works fine ^ $ echo 0 > etm0/enable_source $ rmmod coresight-funnel $ modprobe coresight-funnel $ echo 1 > etm0/enable_source -bash: echo: write error: Invalid argument Fixes: 37ea1ffddffa ("coresight: Use fwnode handle instead of device names") Fixes: 2af89ebacf29 ("coresight: Clear the connection field properly") Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20230425143542.2305069-2-james.clark@arm.com
Diffstat (limited to 'drivers/hwtracing/coresight')
-rw-r--r--drivers/hwtracing/coresight/coresight-core.c9
1 files changed, 2 insertions, 7 deletions
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index d3bf82c0de1d..5733294ce5cd 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1419,13 +1419,8 @@ static int coresight_remove_match(struct device *dev, void *data)
if (csdev->dev.fwnode == conn->child_fwnode) {
iterator->orphan = true;
coresight_remove_links(iterator, conn);
- /*
- * Drop the reference to the handle for the remote
- * device acquired in parsing the connections from
- * platform data.
- */
- fwnode_handle_put(conn->child_fwnode);
- conn->child_fwnode = NULL;
+
+ conn->child_dev = NULL;
/* No need to continue */
break;
}