firmware: arm_scmi: Update the supported clock protocol version

And finally update the supported clock protocol version to v3.2(0x30000).

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240214183006.3403207-6-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add standard clock OEM definitions

Add a common enum to define the standard clock OEM types defined by the
SCMI specification, so as to enable the configuration of such extended
configuration properties with the existent clock protocol operations.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240214183006.3403207-5-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add clock check for extended config support

SCMI v3.2 added support to set/get clock custom OEM types; such support is
conditionally present, though, depending on an extended config attribute
bit possibly advertised by the platform server on a per-domain base.

Add a check to verify if OEM types are supported before allowing any kind
of OEM-specific get/set operation. Also add a check around all the new
v3.2 clock features.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240214183006.3403207-4-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Implement is_notify_supported callback in clock protocol

Add a preliminary check to verify if the clock protocol related notify
enable commands are supported at all by the SCMI platform, and then
provide the callback needed to allow the core SCMI notification
subsytem to do a fine-grain check if a specific resource domain
supports notifications.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240212123233.1230090-7-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Implement clock get permissions

ARM SCMI v3.2 introduces clock get permission command. To implement the
same let us stash the values of those permissions in the scmi_clock_info.
They indicate if the operation is forbidden or not.

If the CLOCK_GET_PERMISSIONS command is not supported, the default
permissions are set to allow the operations, otherwise they will be set
according to the response of CLOCK_GET_PERMISSIONS from the SCMI
platform firmware.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20240121110901.1414856-1-peng.fan@oss.nxp.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Rework clock domain info lookups

Accessing clock domains descriptors by the index from the SCMI drivers
can potentially lead to out-of-bound violations if the SCMI drivers
misbehaves.

Use a common helper to check the consistency of such accesses.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240110120916.2482603-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix the clock protocol supported version

Rollback currently supported SCMI clock protocol version to v2.0 since
some of the mandatory v3.0 features are indeed still not supported yet.

Fixes: b5efc28a754d ("firmware: arm_scmi: Add protocol versioning checks")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240109181716.2338636-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix the clock protocol version for v3.2

The clock protocol version as per the SCMI v3.2 specification is 0x30000.
Enable the v3.0 clock protocol features only when clock protocol version
equals 0x30000.

The previous beta version of the spec had this value set to 0x20001 and
th same value trickled down from the initial development. The version
update were missed in the driver.

Fixes: e49e314a2cf7 ("firmware: arm_scmi: Add clock v3.2 CONFIG_SET support")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240109150106.2066739-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add protocol versioning checks

Platform and agent supported protocols versions do not necessarily match.

When talking to an older SCMI platform, supporting only older protocol
versions, the kernel SCMI agent will downgrade the version of the used
protocol to match the platform and avoid compatibility issues.

In the case where the kernel/OSPM agent happens to communicate with a
newer platform which can support newer protocol versions unknown to
the agent, and potentially backward incompatible, the agent currently
carries on, silently, in a best-effort approach.

Note that the SCMI specification doesn't provide means to explicitly
detect the protocol versions used by the agents, neither it is required
to support multiple, older, protocol versions.

Add an explicit protocol version check to let the agent detect when this
version mismatch happens and warn the user about this condition.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20231201135858.2367651-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add optional flags to extended names helper

Some recently added SCMI protocols needs an additional flags parameter to
be able to properly configure the command used to query the extended name
of a resource.

Modify extended_name_get helper accordingly.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20231114145449.3136412-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add support for clock parents

SCMI v3.2 spec introduces CLOCK_POSSIBLE_PARENTS_GET, CLOCK_PARENT_SET
and CLOCK_PARENT_GET. Add support for these to enable clock parents
and use them in the clock driver.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20231004-scmi-clock-v3-v5-1-1b8a1435673e@nxp.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Rename scmi_{msg_,}clock_config_{get,set}_{2,21}

It is very confusing to use *_v2 for everything applicable until SCMI
clock protocol version v2.0 including v1.0 for example. So let us rename
such that *_v2 is used only for SCMI clock protocol v2.1 onwards. Also
add comment to indicate the same explicitly.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230925101557.3839860-1-sudeep.holla@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add clock OEM config clock operations

Expose a couple of new SCMI clock operations to get and set OEM specific
clock configurations when talking to an SCMI v3.2 compliant.

Issuing such requests against an SCMI platform server not supporting v3.2
extension for OEM specific clock configurations will fail.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230826125308.462328-7-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add clock .state_get support to pre-v3.2

Support clock .state_get operation against SCMI platform servers that do
not support v3.2 CONFIG_GET dedicated command: while talking with these
platforms the command CLOCK_ATTRIBUTES can be used to gather the current
clock states.

Note that, in case of shared resources, the retrieved clock state 'flavour'
(virtual vs physical) depends on the backend SCMI platform server specific
kind of implementation.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230826125308.462328-5-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add v3.2 clock CONFIG_GET support

Add support for v3.2 clock CONFIG_GET command and related new clock
protocol operation state_get() to retrieve the status of a clock.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230826125308.462328-4-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add clock v3.2 CONFIG_SET support

SCMI v3.2 introduces a new clock CONFIG_SET message format that can
optionally carry also OEM specific configuration values beside the usual
clock enable/disable requests.

Refactor internal helpers and add support to use such new format when
talking to a v3.2 compliant SCMI platform.

Support existing enable/disable operations across different clock protocol
versions: this patch still does not add protocol operations to support the
new OEM specific optional configuration capabilities.

No functional change for the SCMI drivers users of the related enable and
disable clock operations.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230826125308.462328-3-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Simplify enable/disable clock operations

SCMI clock enable/disable operations come in 2 different flavours which
simply just differ in how the underlying SCMI transactions is carried on:
atomic or not.

Currently we expose such SCMI operations through 2 distinctly named
wrappers, that, in turn, are wrapped into another couple of similarly and
distinctly named callbacks inside SCMI clock driver user.

Reduce the churn of duplicated wrappers by adding a param to SCMI clock
enable/disable operations to ask for atomic operation while removing the
_atomic version of such operations.

No functional change.

CC: Michael Turquette <mturquette@baylibre.com>
CC: Stephen Boyd <sboyd@kernel.org>
CC: linux-clk@vger.kernel.org
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20230826125308.462328-2-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Improve checks in the info_get operations

SCMI protocols abstract and expose a number of protocol specific
resources like clocks, sensors and so on. Information about such
specific domain resources are generally exposed via an `info_get`
protocol operation.

Improve the sanity check on these operations where needed.

Link: https://lore.kernel.org/r/20220817172731.1185305-3-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: Relax CLOCK_DESCRIBE_RATES out-of-spec checks

A reply to CLOCK_DESCRIBE_RATES issued against a non rate-discrete clock
should be composed of a triplet of rates descriptors (min/max/step)
returned all in one reply message.

This is not always the case when dealing with some SCMI server deployed in
the wild: relax such constraint while maintaining memory safety by checking
carefully the returned payload size.

While at that cleanup a stale debug printout.

Link: https://lore.kernel.org/r/20220616170347.2800771-1-cristian.marussi@arm.com
Fixes: 7bc7caafe6b1 ("firmware: arm_scmi: Use common iterators in the clock protocol")
Tested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Avoid using extended string-buffers sizes if not necessary

Commit b260fccaebdc2 ("firmware: arm_scmi: Add SCMI v3.1 protocol extended
names support") moved all the name string buffers to use the extended buffer
size of 64 instead of the required 16 bytes. While that should be fine if
the firmware terminates the string before 16 bytes, there is possibility
of copying random data if the name is not NULL terminated by the firmware.

SCMI base protocol agent_name/vendor_id/sub_vendor_id are defined by the
specification as NULL-terminated ASCII strings up to 16-bytes in length.

The underlying buffers and message descriptors are currently bigger than
needed; resize them to fit only the strictly needed 16 bytes to avoid
any possible leaks when reading data from the firmware.

Change the size argument of strlcpy to use SCMI_SHORT_NAME_MAX_SIZE always
when dealing with short domain names, so as to limit the possibility that
an ill-formed non-NULL terminated short reply from the SCMI platform
firmware can leak stale content laying in the underlying transport shared
memory area.

While at that, convert all strings handling routines to use the preferred
strscpy.

Link: https://lore.kernel.org/r/20220608095530.497879-1-cristian.marussi@arm.com
Fixes: b260fccaebdc2 ("firmware: arm_scmi: Add SCMI v3.1 protocol extended names support")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Remove all the unused local variables

While using SCMI iterators helpers a few local automatic variables are
defined but then used only as input for sizeof operators.

cppcheck is fooled to complain about this with:

| drivers/firmware/arm_scmi/sensors.c:341:48: warning: Variable 'msg' is
| not assigned a value. [unassignedVariable]
| struct scmi_msg_sensor_list_update_intervals *msg;

Even though this is an innocuos warning, since the uninitialized variable
is at the end never used in the reported cases, fix these occurences all
over SCMI stack to avoid keeping unneeded objects on the stack.

Link: https://lore.kernel.org/r/20220530115237.277077-1-cristian.marussi@arm.com
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add SCMI v3.1 clock notifications

Add SCMI v3.1 clock pre and post notifications.

Link: https://lore.kernel.org/r/20220330150551.2573938-20-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: Use common iterators in the clock protocol

Make SCMI clock protocol use the common iterator protocol helpers for
issuing the multi-part commands.

Link: https://lore.kernel.org/r/20220330150551.2573938-17-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: Parse clock_enable_latency conditionally

The clock_enable_latency field in CLOCK_ATTRIBUTES response message has
been added only since SCMI v3.1. Use the advertised SCMI clock protocol
version as a proper condition check for parsing it, instead of the bare
message length lookup.

Link: https://lore.kernel.org/r/20220330150551.2573938-13-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: Set clock latency to U32_MAX if it is not supported

As per the spec, the clock_enable_delay is the worst case latency
incurred by the platform to enable the clock. The value of 0 indicates
that the platform doesn't support the same and must be considered as
maximum latency for practical purposes.

Currently the value of 0 is assigned as is and is propogated to the clock
framework which can assume that the clock can support atomic enable operation.

Link: https://lore.kernel.org/r/20220428122913.1654821-1-sudeep.holla@arm.com
Fixes: 18f295b758b2 ("firmware: arm_scmi: Add support for clock_enable_latency")
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add SCMI v3.1 protocol extended names support

Using the common protocol helper implementation add support for all new
SCMIv3.1 extended names commands related to all protocols with the
exception of SENSOR_AXIS_GET_NAME.

Link: https://lore.kernel.org/r/20220330150551.2573938-12-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: Split protocol specific definitions in a dedicated header

Move some SCMI protocol specific definitions from common.h into a the new
dedicated protocols.h header so that SCMI protocols core code can include
only what it needs; this is going to be useful to avoid the risk of growing
indefinitely the dimension of common.h, especially when introducing some
common protocols helper functions.

Header common.h will continue to be included by SCMI core and transport
layers.

Link: https://lore.kernel.org/r/20220330150551.2573938-10-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: Remove unneeded NULL termination of clk name

The string array 'name' inside struct scmi_clock_info holds the clock name
which was successfully retrieved by querying the SCMI platform, unless the
related underlying SCMI command failed.

Anyway, such scmi_clock_info structure is allocated using devm_kcalloc()
which in turn internally appends a __GFP_ZERO flag to its invocation:
as a consequence the string 'name' field does not need to be zeroed when
we fail to get the clock name via SCMI, it is already NULL terminated.

Remove unneeded explicit NULL termination.

Link: https://lore.kernel.org/r/20220330150551.2573938-9-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: Check CLOCK_RATE_SET_COMPLETE async response

When CLOCK_RATE_SET command is issued in asynchronous mode the delayed
response CLOCK_RATE_SET_COMPLETE comes back once the SCMI platform has
effectively operated the requested change: such delayed response carries
also the clock ID and the final clock rate that has been set.

As an aid to debug issues, check that the clock ID in the delayed
response matches the expected one and debug print the rate value.

Link: https://lore.kernel.org/r/20220330150551.2573938-8-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: Make protocols initialisation fail on basic errors

Bail out of protocol initialisation routine early when basic information
about protocol version and attributes could not be retrieved. Failing to
act this way can lead to a successfully initialized SCMI protocol which
is in fact not fully functional.

Link: https://lore.kernel.org/r/20220330150551.2573938-3-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: Replace zero-length array with flexible-array member

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://lore.kernel.org/r/20220401075537.2407376-1-lv.ruyi@zte.com.cn
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Fix sorting of retrieved clock rates

During SCMI Clock protocol initialization, after having retrieved from the
SCMI platform all the available discrete rates for a specific clock, the
clock rates array is sorted, unfortunately using a pointer to its end as
a base instead of its start, so that sorting does not work.

Fix invocation of sort() passing as base a pointer to the start of the
retrieved clock rates array.

Link: https://lore.kernel.org/r/20220318092813.49283-1-cristian.marussi@arm.com
Fixes: dccec73de91d ("firmware: arm_scmi: Keep the discrete clock rates sorted")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Add support for clock_enable_latency

An SCMI platform can optionally advertise an enable latency typically
associated with a specific clock resource: add support for parsing such
optional message field and export such information in the usual publicly
accessible clock descriptor.

Link: https://lore.kernel.org/r/20220217131234.50328-8-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: Add atomic support to clock protocol

Introduce new _atomic variant for SCMI clock protocol operations related
to enable disable operations: when an atomic operation is required the xfer
poll_completion flag is set for that transaction.

Link: https://lore.kernel.org/r/20220217131234.50328-7-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: Add protocol modularization support

Extend SCMI protocols accounting mechanism to address possible module
usage and add the support to possibly define new protocols as loadable
modules.

Keep the standard protocols built into the SCMI core.

Link: https://lore.kernel.org/r/20210316124903.35011-38-cristian.marussi@arm.com
Tested-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: Remove legacy scmi_clk_ops protocol interface

Now that all the SCMI driver users have been migrated to the new interface
remove the legacy interface and all the transient code.

Link: https://lore.kernel.org/r/20210316124903.35011-20-cristian.marussi@arm.com
Tested-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: Port clock protocol to new protocols interface

Convert internals of protocol implementation to use protocol handles and
expose a new protocol operations interface for SCMI driver using the new
get/put common operations, while keeping the old handle->clk_ops still
around to ease transition.

Remove handle->clock_priv now unused.

Link: https://lore.kernel.org/r/20210316124903.35011-18-cristian.marussi@arm.com
Tested-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: Extend protocol registration interfaces

Extend common protocol registration routines and provide some new generic
protocols get/put helpers that can track protocols usage and automatically
perform the proper initialization and de-initialization on demand when
required.

Convert all standard protocols to use this new registration scheme while
keeping them all still using the usual initialization logic bound to SCMI
devices probing.

Link: https://lore.kernel.org/r/20210316124903.35011-2-cristian.marussi@arm.com
Tested-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: Add missing Rx size re-initialisation

Few commands provide the list of description partially and require
to be called consecutively until all the descriptors are fetched
completely. In such cases, we don't release the buffers and reuse
them for consecutive transmits.

However, currently we don't reset the Rx size which will be set as
per the response for the last transmit. This may result in incorrect
response size being interpretted as the firmware may repond with size
greater than the one set but we read only upto the size set by previous
response.

Let us reset the receive buffer size to max possible in such cases as
we don't know the exact size of the response.

Link: https://lore.kernel.org/r/20201012141746.32575-1-sudeep.holla@arm.com
Fixes: b6f20ff8bd94 ("firmware: arm_scmi: add common infrastructure and support for base protocol")
Reported-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Move scmi protocols registration into the driver

In preparation to enable building SCMI as a single module, let us move
the SCMI protocol registration call into the driver. This enables us
to also add unregistration of the SCMI protocols.

The main reason for this is to keep it simple instead of maintaining
it as separate modules and dealing with all possible initcall races
and deferred probe handling. We can move it as separate modules if
needed in future.

Link: https://lore.kernel.org/r/20200907195046.56615-4-sudeep.holla@arm.com
Tested-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Constify static scmi-ops

These are never modified, so make them const to allow the compiler to
put them in read-only memory.

Link: https://lore.kernel.org/r/20200906230452.33410-4-rikard.falkeborn@gmail.com
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Use NULL instead of integer 0 for rate pointer

Kbuild test robot reports the following sparse warning:

drivers/firmware/arm_scmi/clock.c:142:21:
sparse: Using plain integer as NULL pointer

Use NULL pointer instead of integer 0 for rate pointer and fix the
warning.

Link: https://lore.kernel.org/r/20200717140405.17905-1-sudeep.holla@arm.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

firmware: arm_scmi: Keep the discrete clock rates sorted

Instead of relying on the firmware to keep the clock rates sorted, let
us sort the list. This is not essential for clock layer but it helps
to find the min and max rates easily from the list.

Link: https://lore.kernel.org/r/20200709081705.46084-1-sudeep.holla@arm.com
Fixes: 5f6c6430e904 ("firmware: arm_scmi: add initial support for clock protocol")
Reported-and-tested-by: Dien Pham <dien.pham.ry@renesas.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Stash version in protocol init functions

In order to avoid querying the individual protocol versions multiple
time with more that one device created for each protocol, we can simple
store the copy in the protocol specific private data and use them whenever
required.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Use {get,put}_unaligned_le{32,64} accessors

Instead of type-casting the {tx,rx}.buf all over the place while
accessing them to read/write __le{32,64} from/to the firmware, let's
use the existing {get,put}_unaligned_le{32,64} accessors to hide all
the type cast ugliness.

Suggested-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Use asynchronous CLOCK_RATE_SET when possible

CLOCK_PROTOCOL_ATTRIBUTES provides attributes to indicate the maximum
number of pending asynchronous clock rate changes supported by the
platform. If it's non-zero, then we should be able to use asynchronous
clock rate set for any clocks until the maximum limit is reached.

Tracking the current count of pending asynchronous clock set rate
requests, we can decide if the incoming/new request for clock set rate
can be handled asynchronously or not until the maximum limit is
reached.

Cc: linux-clk@vger.kernel.org
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: Drop config flag in clk_ops->rate_set

CLOCK_PROTOCOL_ATTRIBUTES provides attributes to indicate the maximum
number of pending asynchronous clock rate changes supported by the
platform. If it's non-zero, then we should be able to use asynchronous
clock rate set for any clocks until the maximum limit is reached.

In order to add that support, let's drop the config flag passed to
clk_ops->rate_set and handle the asynchronous requests dynamically.

Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: update rate_discrete in clock_describe_rates_get

The boolean rate_discrete needs to be assigned to clk->rate_discrete,
so that clock driver can distinguish between the continuous range and
discrete rates. It uses this in scmi_clk_round_rate could get the
rounded value if it's a continuous range.

Fixes: 5f6c6430e904 ("firmware: arm_scmi: add initial support for clock protocol")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
[sudeep.holla: updated commit message]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: use strlcpy to ensure NULL-terminated strings

Replace all the memcpy() for copying name strings from the firmware with
strlcpy() to make sure we are bounded by the source buffer size and we
also always have NULL-terminated strings.

This is needed to avoid out of bounds accesses if the firmware returns
a non-terminated string.

Reported-by: Olof Johansson <olof@lixom.net>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: rename scmi_xfer_{init,get,put}

Just after the initial patches were queued, Jonathan Cameron mentioned
that scmi_one_xfer_{get_put} were not very clear and suggested to use
scmi_xfer_{alloc,free}. While I agree to some extent, the reason not to
have alloc/free as these are preallocated buffers and these functions
just returns a reference to free slot in that preallocated array.
However it was agreed to drop "_one" as it's implicit that we are always
dealing with one slot anyways.

This patch updates the name accordingly dropping "_one" in both {get,put}
functions. Also scmi_one_xfer_init is renamed as scmi_xfer_get_init to
reflect the fact that it gets the free slots and then initialise it.

Reported-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: remove redundant null check on array

The null check on clk->name is redundant since name is a char array
and can never be null, so the check is always true. Remove it.

Detected by CoverityScan, CID#1466117 ("Array compared against 0")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: prevent accessing rate_discrete uninitialized

gcc-5.3 and earlier warns that rate_discrete maybe-uninitialized
../drivers/firmware/arm_scmi/clock.c:185:5: warning: 'rate_discrete'
may be used uninitialized in this function [-Wmaybe-uninitialized]
if (rate_discrete)
^
../drivers/firmware/arm_scmi/clock.c:128:7: note:
'rate_discrete' was declared here
bool rate_discrete;
^
This patch fixing the warning by initialising rate_discrete and also using
goto label for the error path.

Fixes: 5f6c6430e904 ("firmware: arm_scmi: add initial support for clock protocol")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
[sudeep.holla: added one line description to the commit message]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

firmware: arm_scmi: add initial support for clock protocol

The clock protocol is intended for management of clocks. It is used to
enable or disable clocks, and to set and get the clock rates. This
protocol provides commands to describe the protocol version, discover
various implementation specific attributes, describe a clock, enable
and disable a clock and get/set the rate of the clock synchronously or
asynchronously.

This patch adds initial support for the clock protocol.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>