Re: [PATCH v9 12/12] arm_mpam: detect and enable MPAM-Fb PCC support
flat view
From: Srivathsa L Rao <hidden>
Date: 2026-08-26 17:43:34
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linux-acpi, lkml
On 8/7/2026 4:24 PM, Andre Przywara wrote:
quoted hunk ↗ jump to hunk
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. There can be multiple PCC channels, and each channel can serve multiple MSCs, so we need to keep track of the channel usage, using a list and a refcount. 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@arm.com> Tested-by: Ritwick Sharma <redacted> # on Arm AGI CPU Reviewed-by: Jonathan Cameron <redacted> Tested-by: Srivathsa L Rao <redacted> --- drivers/resctrl/mpam_devices.c | 112 +++++++++++++++++++++++++++++++- drivers/resctrl/mpam_fb.c | 41 ++++++++++++ drivers/resctrl/mpam_internal.h | 2 + 3 files changed, 153 insertions(+), 2 deletions(-)diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 4b1382fce2be..4d3f13044b43 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c
Reviewed-by: Srivathsa L Rao <redacted>