[PATCH 5/5] arm_mpam: detect and enable MPAM-Fb PCC support

[Sudeep Holla]

On Wed, Apr 29, 2026 at 04:13:39PM +0200, Andre Przywara wrote:
> The Arm MPAM-Fb specification [1] describes a protocol to access MSC
> registers through a firmware interface. This requires a shared memory
> region to hold the message, and a mailbox to trigger the access.
> For ACPI this is wrapped as a PCC channel, described using existing
> ACPI abstractions.
> 
> Add code to parse those PCC table descriptions associated with an MSC,
> and store the parsed information in the MSC struct.
> This will be used by the MPAM-Fb access wrapper code.
> 
> [1] https://developer.arm.com/documentation/den0144/latest
> 
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>  drivers/acpi/arm64/mpam.c      |  2 ++
>  drivers/resctrl/mpam_devices.c | 46 +++++++++++++++++++++++++++++++---
>  2 files changed, 45 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/arm64/mpam.c b/drivers/acpi/arm64/mpam.c
> index 99c2bdbb3314..edb4d10e8dc3 100644
> --- a/drivers/acpi/arm64/mpam.c
> +++ b/drivers/acpi/arm64/mpam.c
> @@ -341,6 +341,8 @@ static struct platform_device * __init acpi_mpam_parse_msc(struct acpi_mpam_msc_
>  	} else if (iface == MPAM_IFACE_PCC) {
>  		props[next_prop++] = PROPERTY_ENTRY_U32("pcc-channel",
>  							tbl_msc->base_address);
> +		props[next_prop++] = PROPERTY_ENTRY_U32("msc-id",
> +							tbl_msc->identifier);

I may be looking at the wrong documents, but neither DEN0065 nor DEN0144 carry
any definitions of pcc-channel and msc-id for the device with HID
"“ARMHAA5C". Since "pcc-channel" is already merged, I think I am looking at
wrong documents, please point me to the right one.

-- 
Regards,
Sudeep