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Subject[PATCH 7/8] bus: fsl-mc: rescan devices if endpoint not found
Date
From: Laurentiu Tudor <laurentiu.tudor@nxp.com>

If the endpoint of a device is not yet probed on the bus, force
a rescan of the devices and retry to get a reference to the
endpoint device. If the device is still not found then we assume
it's in a different isolation context (container/DPRC) thus
unavailable and return a permission error.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Robert-Ionut Alexa <robert-ionut.alexa@nxp.com>
---
drivers/bus/fsl-mc/fsl-mc-bus.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index e5b4830cf3c5..31595017d207 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -950,10 +950,28 @@ struct fsl_mc_device *fsl_mc_get_endpoint(struct fsl_mc_device *mc_dev)
* We know that the device has an endpoint because we verified by
* interrogating the firmware. This is the case when the device was not
* yet discovered by the fsl-mc bus, thus the lookup returned NULL.
- * Differentiate this case by returning EPROBE_DEFER.
+ * Force a rescan of the devices in this container and retry the lookup.
+ */
+ if (!endpoint) {
+ struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_bus_dev);
+
+ if (mutex_trylock(&mc_bus->scan_mutex)) {
+ err = dprc_scan_objects(mc_bus_dev, true);
+ mutex_unlock(&mc_bus->scan_mutex);
+ }
+
+ if (err < 0)
+ return ERR_PTR(err);
+ }
+
+ endpoint = fsl_mc_device_lookup(&endpoint_desc, mc_bus_dev);
+ /*
+ * This means that the endpoint might reside in a different isolation
+ * context (DPRC/container). Not much to do, so return a permssion
+ * error.
*/
if (!endpoint)
- return ERR_PTR(-EPROBE_DEFER);
+ return ERR_PTR(-EPERM);

return endpoint;
}
--
2.17.1
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