ACPI: PCC: Setup PCC Opregion handler only if platform interrupt is available

Currently, PCC OpRegion handler depends on the availability of platform
interrupt to be functional currently. If it is not available, the OpRegion
can't be executed successfully or the desired outcome won't be possible.
So let's reject setting up the PCC OpRegion handler on the platform if
it doesn't support or have platform interrupt available.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: PCC: Fix unintentional integer overflow

Fix an unintentional u32 overflow by changing PCC_CMD_WAIT_RETRIES_NUM
to 500ULL.

Fixes: 91cefefb6991 ("ACPI: PCC: replace wait_for_completion()")
Signed-off-by: Manank Patel <pmanank200502@gmail.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Huisong Li <lihuisong@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: PCC: Fix Tx acknowledge in the PCC address space handler

Currently, mbox_client_txdone() is called from the PCC address space
handler and that expects the user the Tx state machine to be controlled
by the client which is not the case and the below warning is thrown:

| PCCT: Client can't run the TX ticker

Let the controller run the state machine and the end of Tx can be
acknowledge by calling mbox_chan_txdone() instead.

Fixes: 77e2a04745ff ("ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype")
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: PCC: replace wait_for_completion()

Currently, the function waiting for completion of mailbox operation is
'wait_for_completion()'. The PCC method will be permanently blocked if
this mailbox message fails to execute. So this patch replaces it with
'wait_for_completion_timeout()'. And set the timeout interval to an
arbitrary retries on top of nominal to prevent the remote processor is
slow to respond to PCC commands.

Fixes: 77e2a04745ff ("ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype")
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: PCC: Release resources on address space setup failure path

The allocated memory for the pcc_data struct doesn't get freed under an
error path in pcc_mbox_request_channel() or acpi_os_ioremap(). Also, the
PCC mailbox channel doesn't get freed under an error path in
acpi_os_ioremap().

Fixes: 77e2a04745ff8 ("ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype")
Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: PCC: pcc_ctx can be static

drivers/acpi/acpi_pcc.c:34:22: warning: symbol 'pcc_ctx' was not declared. Should it be static?

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype

PCC OpRegion provides a mechanism to communicate with the platform
directly from the AML. PCCT provides the list of PCC channel available
in the platform, a subset or all of them can be used in PCC Opregion.

This patch registers the PCC OpRegion handler before ACPI tables are
loaded. This relies on the special context data passed to identify and
set up the PCC channel before the OpRegion handler is executed for the
first time.

Typical PCC Opregion declaration looks like this:

OperationRegion (PFRM, PCC, 2, 0x74)
Field (PFRM, ByteAcc, NoLock, Preserve)
{
SIGN, 32,
FLGS, 32,
LEN, 32,
CMD, 32,
DATA, 800
}

It contains four named double words followed by 100 bytes of buffer
names DATA.

ASL can fill out the buffer something like:

/* Create global or local buffer */
Name (BUFF, Buffer (0x0C){})
/* Create double word fields over the buffer */
CreateDWordField (BUFF, 0x0, WD0)
CreateDWordField (BUFF, 0x04, WD1)
CreateDWordField (BUFF, 0x08, WD2)

/* Fill the named fields */
WD0 = 0x50434300
SIGN = BUFF
WD0 = 1
FLGS = BUFF
WD0 = 0x10
LEN = BUFF

/* Fill the payload in the DATA buffer */
WD0 = 0
WD1 = 0x08
WD2 = 0
DATA = BUFF

/* Write to CMD field to trigger handler */
WD0 = 0x4404
CMD = BUFF

This buffer is received by acpi_pcc_opregion_space_handler. This
handler will fetch the complete buffer via internal_pcc_buffer.

The setup handler will receive the special PCC context data which will
contain the PCC channel index which used to set up the channel. The
buffer pointer and length is saved in region context which is then used
in the handler.

(kernel test robot: Build failure with CONFIG_ACPI_DEBUGGER)
Link: https://lore.kernel.org/r/202201041539.feAV0l27-lkp@intel.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>