firmware: arm_scmi: Fix struct kernel-doc warnings in optee transport

Fix the kernel-doc notation for the nested union in struct
scmi_optee_channel to eliminate kernel-doc warnings:

| optee.c:130: warning: Excess struct member 'shmem' description
| in 'scmi_optee_channel'
| optee.c:131: warning: Function parameter or struct member 'req'
| not described in 'scmi_optee_channel'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Cristian Marussi <cristian.marussi@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240221062157.8694-1-rdunlap@infradead.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: optee: use optee system invocation

Changes SCMI optee transport to call tee_client_system_session()
to request optee driver to provision an entry context in OP-TEE
for processing OP-TEE messages. This prevents possible deadlock
in case OP-TEE threads are all consumed while these may be waiting
for a clock or regulator to be enable which SCMI OP-TEE service which
requires a free thread context to execute.

Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Cristian Marussi <cristian.marussi@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

firmware: Use of_property_present() for testing DT property presence

It is preferred to use typed property access functions (i.e.
of_property_read_<type> functions) rather than low-level
of_get_property/of_find_property functions for reading properties. As
part of this, convert of_get_property/of_find_property calls to the
recently added of_property_present() helper when we just want to test
for presence of a property and nothing more.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

firmware: arm_scmi: Use dedicated devices to initialize channels

Refactor channels initialization to use dedicated transport devices
instead of using devices borrowed from the SCMI drivers.

Initialize all channels, as described in the device tree, upfront during
SCMI core stack probe phase and free all of them, including the underlying
devices, when the SCMI core is removed.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222185049.737625-3-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Simplify chan_available transport operation

SCMI transport operation .chan_available determines in a transport
specific way if an SCMI channel is still available and to be configured.
Such information is derived by analyzing bits of device node in a
transport specific way, all it needs is a device node to operate up on,
not necessarily a full blown device.

Simplify the helper to receive in input a reference to a device_node
instead of a device carrying a pointer to such device_node.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222185049.737625-2-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Make tx_prepare time out eventually

SCMI transports based on shared memory, at start of transmissions, have
to wait for the shared Tx channel area to be eventually freed by the
SCMI platform before accessing the channel. In fact the channel is owned
by the SCMI platform until marked as free by the platform itself and,
as such, cannot be used by the agent until relinquished.

As a consequence a badly misbehaving SCMI platform firmware could lock
the channel indefinitely and make the kernel side SCMI stack loop
forever waiting for such channel to be freed, possibly hanging the
whole boot sequence.

Add a timeout to the existent Tx waiting spin-loop so that, when the
system ends up in this situation, the SCMI stack can at least bail-out,
nosily warn the user, and abort the transmission.

Reported-by: YaxiongTian <iambestgod@outlook.com>
Suggested-by: YaxiongTian <iambestgod@outlook.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Etienne Carriere <etienne.carriere@linaro.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221028140833.280091-3-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix missing kernel-doc in optee

Add the missing structure field `rx_len` description.

Link: https://lore.kernel.org/r/20220817172731.1185305-2-cristian.marussi@arm.com
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix response size warning for OPTEE transport

Some protocols check the response size with the expected value but optee
shared memory doesn't return such size whereas it is available in the
optee output buffer.

As an example, the base protocol compares the response size with the
expected result when requesting the list of protocol which triggers a
warning with optee shared memory:

arm-scmi firmware:scmi0: Malformed reply - real_sz:116 calc_sz:4 (loop_num_ret:4)

Save the output buffer length and use it when fetching the answer.

Link: https://lore.kernel.org/r/20220624074549.3298-1-vincent.guittot@linaro.org
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Support optee shared memory in the optee transport

Add support for TEE shared memory in optee scmi transport. When using
tee shared memory, scmi optee transport manages SCMI messages using
msg protocol(from msg.c) in shared memory, whereas smt(from shmem.c)
protocol is used with static IOMEM based shared buffers.

Link: https://lore.kernel.org/r/20220425085127.2009-1-etienne.carriere@linaro.org
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix sparse warnings in OPTEE transport driver

The sparse checker complains about converting pointers between address
spaces. We correctly stored an __iomem pointer in struct scmi_optee_channel,
but discarded the __iomem when returning it from get_channel_shm, causing one
warning. Then we passed the non-__iomem pointer return from get_channel_shm
at two other places, where an __iomem pointer is expected, causing couple of
other warnings

Add the appropriate __iomem annotations at all places where it is missing.

optee.c:414:20: warning: incorrect type in return expression (different address spaces)
optee.c:414:20: expected struct scmi_shared_mem *
optee.c:414:20: got struct scmi_shared_mem [noderef] __iomem *shmem
optee.c:426:26: warning: incorrect type in argument 1 (different address spaces)
optee.c:426:26: expected struct scmi_shared_mem [noderef] __iomem *shmem
optee.c:426:26: got struct scmi_shared_mem *shmem
optee.c:441:30: warning: incorrect type in argument 1 (different address spaces)
optee.c:441:30: expected struct scmi_shared_mem [noderef] __iomem *shmem
optee.c:441:30: got struct scmi_shared_mem *shmem

Link: https://lore.kernel.org/r/20220404102419.1159705-1-sudeep.holla@arm.com
Cc: Etienne Carriere <etienne.carriere@linaro.org>
Cc: Cristian Marussi <cristian.marussi@arm.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add new parameter to mark_txdone

Add a new xfer parameter to mark_txdone transport operation which enables
the SCMI core to optionally pass back into the transport layer a reference
to the xfer descriptor that is being handled.

Link: https://lore.kernel.org/r/20211220195646.44498-9-cristian.marussi@arm.com
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Make optee support sync_cmds_completed_on_ret

Declare each OPTEE SCMI channel as not having a completion_irq so as to
enable polling mode and then enable also .sync_cmds_completed_on_ret flag
in the OPTEE transport descriptor so that real polling is itself
effectively bypassed on the rx path: once the optee command invocation has
successfully returned the core will directly fetch the response from the
shared memory area.

Remove OPTEE SCMI transport specific .poll_done callback support since
real polling is effectively bypassed when .sync_cmds_completed_on_ret is
set.

Add OPTEE SCMI transport specific .mark_txdone callback support in order to
properly handle channel locking along the tx path.

Link: https://lore.kernel.org/r/20211220195646.44498-6-cristian.marussi@arm.com
Cc: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: optee: Drop the support for the OPTEE shared dynamic buffer

The shared memory buffer allocated by the optee driver is normal cached
memory and can't be used with IOMEM APIs used in shmem_*.

We currently support only IO memory for shared memory and supporting
normal cached memory needs more changes and needs to be thought through
properly. So for now, let us drop the support for this OPTEE shared buffer.

Link: https://lore.kernel.org/r/20211125150730.188487-1-sudeep.holla@arm.com
Cc: Cristian Marussi <cristian.marussi@arm.com>
Cc: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: optee: Fix missing mutex_init()

The driver allocates the mutex but not initialize it.
Use mutex_init() on it to initialize it correctly.

Link: https://lore.kernel.org/r/20211123083620.2366860-1-weiyongjun1@huawei.com
Fixes: 5f90f189a052 ("firmware: arm_scmi: Add optee transport")
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add optee transport

Add a new transport channel to the SCMI firmware interface driver for
SCMI message exchange based on optee transport channel. The optee
transport is realized by connecting and invoking OP-TEE SCMI service
interface PTA.

Optee transport support (CONFIG_ARM_SCMI_TRANSPORT_OPTEE) is default
enabled when optee driver (CONFIG_OPTEE) is enabled. Effective optee
transport is setup upon OP-TEE SCMI service discovery at optee
device initialization. For this SCMI UUID is registered to the optee
bus for probing. This is done from the link_supplier operator of the
SCMI optee transport.

The optee transport can use a statically defined shared memory in
which case SCMI device tree node defines it using an "arm,scmi-shmem"
compatible phandle through property shmem. Alternatively, optee transport
allocates the shared memory buffer from the optee driver when no shmem
property is defined.

The protocol used to exchange SCMI message over that shared memory is
negotiated between optee transport driver and the OP-TEE service through
capabilities exchange.

OP-TEE SCMI service is integrated in OP-TEE since its release tag 3.13.0.
The service interface is published in [1].

Link: [1] https://github.com/OP-TEE/optee_os/blob/3.13.0/lib/libutee/include/pta_scmi_client.h
Link: https://lore.kernel.org/r/20211028140009.23331-2-etienne.carriere@linaro.org
Cc: Cristian Marussi <cristian.marussi@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>