ACPI: PCC: Add PCC shared memory region command and status bitfields

Define the common macros to use when referring to various bitfields in
the PCC generic communications channel command and status fields.

Currently different drivers that need to use these bitfields have defined
these locally. This common macro is intended to consolidate and replace
those.

Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20230927-pcc_defines-v2-1-0b8ffeaef2e5@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

mailbox: pcc: Use PCC mailbox channel pointer instead of standard

Now that we have all the shared memory region information populated in
the pcc_mbox_chan, let us propagate the pointer to the same as the
return value to pcc_mbox_request channel.

This eliminates the need for the individual users of PCC mailbox to
parse the PCCT subspace entries and fetch the shmem information. This
also eliminates the need for PCC mailbox controller to set con_priv to
PCCT subspace entries. This is required as con_priv is private to the
controller driver to attach private data associated with the channel and
not meant to be used by the mailbox client/users.

Let us convert all the users of pcc_mbox_{request,free}_channel to use
new interface.

Cc: Jean Delvare <jdelvare@suse.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Wolfram Sang <wsa@kernel.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

mailbox: pcc: Add pcc_mbox_chan structure to hold shared memory region info

Currently PCC mailbox controller sets con_priv in each channel to hold
the pointer to pcct subspace entry it corresponds to. The mailbox user
will then fetch this pointer from the channel descriptor they get when
they request for the channel. Using that pointer they then parse the
pcct entry again to fetch all the information about shared memory region.

In order to remove individual users of PCC mailbox parsing the PCCT
subspace entries to fetch same information, let us consolidate the same
in pcc mailbox controller by parsing all the shared memory region
information into a structure that can also hold the mbox_chan pointer it
represent.

This can then be used as main PCC mailbox channel pointer that we can
return as part of pcc_mbox_request_channel instead of standard mailbox
channel pointer.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mailbox: PCC: Move the MAX_PCC_SUBSPACES definition to header file

Move the MAX_PCC_SUBSPACES definition to acpi/pcc.h file in
preparation to add subspace ID support for cppc_acpi driver.

Signed-off-by: George Cherian <george.cherian@cavium.com>
Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

mailbox: PCC: Fix return value of pcc_mbox_request_channel()

When CONFIG_PCC is disabled, pcc_mbox_request_channel() needs to
return ERR_PTR(-ENODEV), not a NULL pointer, as the callers of
this function use IS_ERR() to check for error code.

Signed-off-by: Duc Dang <dhdang@apm.com>
Signed-off-by: Hoan Tran <hotran@apm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

mailbox: pcc: Add PCC request and free channel declarations

Exports pcc_mbox_request_channel() and pcc_mbox_free_channel()
declarations into a pcc.h header file.

Looks-good-to: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Hoan Tran <hotran@apm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>