The device/driver model clearly mandates that bus driver that discover
and allocate the device must set the release callback. This callback
will be used to free the device after all references have gone away.
scmi bus driver is missing the obvious callback which will result in
the following warning if the device is unregistered:
Device 'scmi_dev.1' does not have a release() function, it is broken and
must be fixed. See Documentation/kobject.txt.
WARNING at drivers/base/core.c:922 device_release+0x8c/0xa0
Hardware name: ARM LTD Juno Development Platform BIOS EDK II Jan 21 2019
Workqueue: events deferred_probe_work_func
pstate: 60000005 (nZCv daif -PAN -UAO)
pc : device_release+0x8c/0xa0
lr : device_release+0x8c/0xa0
Call trace:
device_release+0x8c/0xa0
kobject_put+0x8c/0x208
device_unregister+0x30/0x78
scmi_device_destroy+0x28/0x50
scmi_probe+0x354/0x5b0
platform_drv_probe+0x58/0xa8
really_probe+0x2c4/0x3e8
driver_probe_device+0x12c/0x148
__device_attach_driver+0xac/0x150
bus_for_each_drv+0x78/0xd8
__device_attach+0xe0/0x168
device_initial_probe+0x24/0x30
bus_probe_device+0xa0/0xa8
deferred_probe_work_func+0x8c/0xe0
process_one_work+0x1f0/0x478
worker_thread+0x22c/0x450
kthread+0x134/0x138
ret_from_fork+0x10/0x1c
---[ end trace 420bdb7f6af50937 ]---
Fix the issue by providing scmi_device_release callback. We have
everything required for device release already in scmi_device_destroy,
so we just need to move freeing of the device to scmi_device_release.
Fixes: 933c504424 ("firmware: arm_scmi: add scmi protocol bus to enumerate protocol devices")
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: stable@vger.kernel.org # 4.17+
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The existing code intends the good path to reduce the code which is so
uncommon. It's obvious to have more readable code with a goto used for
the error path. This patch adds more appropriate error paths and makes
code more readable. It also moves a error logging outside the scope of
locking.
Suggested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
The SCMI specification encompasses various protocols. However, not every
protocol has to be present on a given platform/implementation as not
every protocol is relevant for it.
Furthermore, the platform chooses which protocols it exposes to a given
agent. The only protocol that must be implemented is the base protocol.
The base protocol is used by an agent to discover which protocols are
available to it.
In order to enumerate the discovered implemented protocols, this patch
adds support for a separate scmi protocol bus. It also adds mechanism to
register support for different protocols.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
