firmware: arm_scmi: Make raw debugfs entries non-seekable

SCMI raw debugfs entries are used to inject and snoop messages out of the
SCMI core and, as such, the underlying virtual files have no reason to
support seeking.

Modify the related file_operations descriptors to be non-seekable.

Fixes: 3c3d818a9317 ("firmware: arm_scmi: Add core raw transmission support")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240315140324.231830-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Use xa_insert() when saving raw queues

Use xa_insert() when saving per-channel raw queues to better check for
duplicates.

Fixes: 7860701d1e6e ("firmware: arm_scmi: Add per-channel raw injection support")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240108185050.1628687-2-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix signed error return values handling

Handle signed error return values returned by simple_write_to_buffer().
In case of an error, return the error code.

Fixes: 3c3d818a9317 ("firmware: arm_scmi: Add core raw transmission support")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Sukrut Bellary <sukrut.bellary@linux.com>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Cristian Marussi <cristian.marussi@arm.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20230718085529.258899-1-sukrut.bellary@linux.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix incorrect alloc_workqueue() invocation

scmi_xfer_raw_worker_init() is specifying a flag, WQ_SYSFS, as @max_active.
Fix it by or'ing WQ_SYSFS into @flags so that it actually enables sysfs
interface and using 0 for @max_active for the default setting.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 3c3d818a9317 ("firmware: arm_scmi: Add core raw transmission support")
Link: https://lore.kernel.org/r/ZEGTnajiQm7mkkZS@slm.duckdns.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add per-channel raw injection support

On a system configured with multiple transport channels, expose a few
additional debugfs per-channel entries to allow a user to explicitly select
which transport channel to use for the SCMI message injection.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20230118121426.492864-18-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add the raw mode co-existence support

When the raw support is enabled and configured in co-existence mode the
normal SCMI drivers are allowed to register with the SCMI core and
operate as usual alongside the raw operations.

SCMI normal and raw messages will be kept segregated from each other,
but only at the transaction level. Any further possible interference at
the protocol layer will have instead to be handled by the user to attain
reliable results while using the raw transactions.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20230118121426.492864-17-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add core raw transmission support

Add SCMI raw mode support which exposes a userspace interface to allow for
bare SCMI command injection and snooping from userspace.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20230118121426.492864-13-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>