Merge tag 'scmi-updates-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into soc/drivers

Arm SCMI updates for v6.3

The main addition is a unified userspace interface for SCMI irrespective
of the underlying transport and along with some changed to refactor the
SCMI stack probing sequence.

1. SCMI unified userspace interface

   This is to have a unified way of testing an SCMI platform firmware
   implementation for compliance, fuzzing etc., from the perspective of
   the non-secure OSPM irrespective of the underlying transport supporting
   SCMI. It is just for testing/development and not a feature intended fo
   use in production.

   Currently an SCMI Compliance Suite[1] can only work by injecting SCMI
   messages using the mailbox test driver only which makes it transport
   specific and can't be used with any other transport like virtio,
   smc/hvc, optee, etc. Also the shared memory can be transport specific
   and it is better to even abstract/hide those details while providing
   the userspace access. So in order to scale with any transport, we need
   a unified interface for the same.

   In order to achieve that, SCMI "raw mode support" is being added through
   debugfs which is more configurable as well. A userspace application
   can inject bare SCMI binary messages into the SCMI core stack; such
   messages will be routed by the SCMI regular kernel stack to the backend
   platform firmware using the configured transport transparently. This
   eliminates the to know about the specific underlying transport
   internals that will be taken care of by the SCMI core stack itself.
   Further no additional changes needed in the device tree like in the
   mailbox-test driver.

[1] https://gitlab.arm.com/tests/scmi-tests

2. Refactoring of the SCMI stack probing sequence

   On some platforms, SCMI transport can be provide by OPTEE/TEE which
   introduces certain dependency in the probe ordering. In order to address
   the same, the SCMI bus is split into its own module which continues to
   be initialized at subsys_initcall, while the SCMI core stack, including
   its various transport backends (like optee, mailbox, virtio, smc), is
   now moved into a separate module at module_init level.

   This allows the other possibly dependent subsystems to register and/or
   access SCMI bus well before the core SCMI stack and its dependent
   transport backends.

* tag 'scmi-updates-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux: (31 commits)
  firmware: arm_scmi: Clarify raw per-channel ABI documentation
  firmware: arm_scmi: Add per-channel raw injection support
  firmware: arm_scmi: Add the raw mode co-existence support
  firmware: arm_scmi: Call raw mode hooks from the core stack
  firmware: arm_scmi: Reject SCMI drivers when configured in raw mode
  firmware: arm_scmi: Add debugfs ABI documentation for raw mode
  firmware: arm_scmi: Add core raw transmission support
  firmware: arm_scmi: Add debugfs ABI documentation for common entries
  firmware: arm_scmi: Populate a common SCMI debugfs root
  debugfs: Export debugfs_create_str symbol
  include: trace: Add platform and channel instance references
  firmware: arm_scmi: Add internal platform/channel identifiers
  firmware: arm_scmi: Move errors defs and code to common.h
  firmware: arm_scmi: Add xfer helpers to provide raw access
  firmware: arm_scmi: Add flags field to xfer
  firmware: arm_scmi: Refactor scmi_wait_for_message_response
  firmware: arm_scmi: Refactor polling helpers
  firmware: arm_scmi: Refactor xfer in-flight registration routines
  firmware: arm_scmi: Split bus and driver into distinct modules
  firmware: arm_scmi: Introduce a new lifecycle for protocol devices
  ...

Link: https://lore.kernel.org/r/20230120162152.1438456-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

2 files changed, 187 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/debugfs-scmi b/Documentation/ABI/testing/debugfs-scmi
new file mode 100644
index 000000000000..ee7179ab2edf
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-scmi
@@ -0,0 +1,70 @@
+What:		/sys/kernel/debug/scmi/<n>/instance_name
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	The name of the underlying SCMI instance <n> described by
+		all the debugfs accessors rooted at /sys/kernel/debug/scmi/<n>,
+		expressed as the full name of the top DT SCMI node under which
+		this SCMI instance is rooted.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/atomic_threshold_us
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	An optional time value, expressed in microseconds, representing,
+		on this SCMI instance <n>, the threshold above which any SCMI
+		command, advertised to have an higher-than-threshold execution
+		latency, should not be considered for atomic mode of operation,
+		even if requested.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/type
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	A string representing the type of transport configured for this
+		SCMI instance <n>.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/is_atomic
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	A boolean stating if the transport configured on the underlying
+		SCMI instance <n> is capable of atomic mode of operation.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/max_rx_timeout_ms
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Timeout in milliseconds allowed for SCMI synchronous replies
+		for the currently configured SCMI transport for instance <n>.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/max_msg_size
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Max message size of allowed SCMI messages for the currently
+		configured SCMI transport for instance <n>.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/tx_max_msg
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Max number of concurrently allowed in-flight SCMI messages for
+		the currently configured SCMI transport for instance <n> on the
+		TX channels.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/rx_max_msg
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Max number of concurrently allowed in-flight SCMI messages for
+		the currently configured SCMI transport for instance <n> on the
+		RX channels.
+Users:		Debugging, any userspace test suite
diff --git a/Documentation/ABI/testing/debugfs-scmi-raw b/Documentation/ABI/testing/debugfs-scmi-raw
new file mode 100644
index 000000000000..97678cc9535c
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-scmi-raw
@@ -0,0 +1,117 @@
+What:		/sys/kernel/debug/scmi/<n>/raw/message
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw synchronous message injection/snooping facility; write
+		a complete SCMI synchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n>.
+		Any subsequently received response can be read from this same
+		entry if it arrived within the configured timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/message_async
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw asynchronous message injection/snooping facility; write
+		a complete SCMI asynchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n>.
+		Any subsequently received response can be read from this same
+		entry if it arrived within the configured timeout.
+		Any additional delayed response received afterwards can be read
+		from this same entry too if it arrived within the configured
+		timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/errors
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw message errors facility; any kind of timed-out or
+		generally unexpectedly received SCMI message, for instance <n>,
+		can be read from this entry.
+		Each read gives back one message at time (receiving an EOF at
+		each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/notification
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw notification snooping facility; any notification
+		emitted by the backend SCMI server, for instance <n>, can be
+		read from this entry.
+		Each read gives back one message at time (receiving an EOF at
+		each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/reset
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw stack reset facility; writing a value to this entry
+		causes the internal queues of any kind of received message,
+		still pending to be read out for instance <n>, to be immediately
+		flushed.
+		Can be used to reset and clean the SCMI Raw stack between to
+		different test-run.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/channels/<m>/message
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw synchronous message injection/snooping facility; write
+		a complete SCMI synchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n> through the <m> transport
+		channel.
+		Any subsequently received response can be read from this same
+		entry if it arrived on channel <m> within the configured
+		timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+		Channel identifier <m> matches the SCMI protocol number which
+		has been associated with this transport channel in the DT
+		description, with base protocol number 0x10 being the default
+		channel for this instance.
+		Note that these per-channel entries rooted at <..>/channels
+		exist only if the transport is configured to have more than
+		one default channel.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/channels/<m>/message_async
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw asynchronous message injection/snooping facility; write
+		a complete SCMI asynchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n> through the <m> transport
+		channel.
+		Any subsequently received response can be read from this same
+		entry if it arrived on channel <m> within the configured
+		timeout.
+		Any additional delayed response received afterwards can be read
+		from this same entry too if it arrived within the configured
+		timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+		Channel identifier <m> matches the SCMI protocol number which
+		has been associated with this transport channel in the DT
+		description, with base protocol number 0x10 being the default
+		channel for this instance.
+		Note that these per-channel entries rooted at <..>/channels
+		exist only if the transport is configured to have more than
+		one default channel.
+Users:		Debugging, any userspace test suite