The fsl-mc bus associated to the root DPRC in a DPAA2 system exports a device file for userspace access to the MC firmware. In case the DPRC's local MC portal (DPMCP) is currently in use, a new DPMCP device is allocated through the fsl_mc_portal_allocate() function.

In this case, the call to fsl_mc_portal_allocate() will fail with -EINVAL when trying to add a device link between the root DPRC (consumer) and the newly allocated DPMCP device (supplier). This is because the DPMCP is a dependent of the DPRC device (the bus).

Fix this by not adding a device link in case the DPMCP is allocated for the root DPRC's usage.

Fixes: afb77422819f ("bus: fsl-mc: automatically add a device_link on fsl_mc_[portal,object]_allocate") Signed-off-by: Ioana Ciornei ioana.ciornei@nxp.com Cc: stable@vger.kernel.org --- drivers/bus/fsl-mc/mc-io.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/bus/fsl-mc/mc-io.c b/drivers/bus/fsl-mc/mc-io.c index a0ad7866cbfc..cd8754763f40 100644 --- a/drivers/bus/fsl-mc/mc-io.c +++ b/drivers/bus/fsl-mc/mc-io.c @@ -214,12 +214,19 @@ int __must_check fsl_mc_portal_allocate(struct fsl_mc_device *mc_dev, if (error < 0) goto error_cleanup_resource;

- dpmcp_dev->consumer_link = device_link_add(&mc_dev->dev, - &dpmcp_dev->dev, - DL_FLAG_AUTOREMOVE_CONSUMER); - if (!dpmcp_dev->consumer_link) { - error = -EINVAL; - goto error_cleanup_mc_io; + /* If the DPRC device itself tries to allocate a portal (usually for + * UAPI interaction), don't add a device link between them since the + * DPMCP device is an actual child device of the DPRC and a reverse + * dependency is not allowed. + */ + if (mc_dev != mc_bus_dev) { + dpmcp_dev->consumer_link = device_link_add(&mc_dev->dev, + &dpmcp_dev->dev, + DL_FLAG_AUTOREMOVE_CONSUMER); + if (!dpmcp_dev->consumer_link) { + error = -EINVAL; + goto error_cleanup_mc_io; + } }

*new_mc_io = mc_io;