On Fri, Jul 11, 2025 at 06:36:25PM +0000, James Morse wrote:

Probing MPAM is convoluted. MSCs that are integrated with a CPU may
only be accessible from those CPUs, and they may not be online.
Touching the hardware early is pointless as MPAM can't be used until
the system-wide common values for num_partid and num_pmg have been
discovered.

Start with driver probe/remove and mapping the MSC.

CC: Carl Worth <redacted>
Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/arm64/Kconfig                          |   1 +
 drivers/platform/arm64/Kconfig              |   1 +
 drivers/platform/arm64/Makefile             |   1 +
 drivers/platform/arm64/mpam/Kconfig         |  10 +
 drivers/platform/arm64/mpam/Makefile        |   4 +
 drivers/platform/arm64/mpam/mpam_devices.c  | 336 ++++++++++++++++++++
 drivers/platform/arm64/mpam/mpam_internal.h |  62 ++++
 7 files changed, 415 insertions(+)
 create mode 100644 drivers/platform/arm64/mpam/Kconfig
 create mode 100644 drivers/platform/arm64/mpam/Makefile
 create mode 100644 drivers/platform/arm64/mpam/mpam_devices.c
 create mode 100644 drivers/platform/arm64/mpam/mpam_internal.h

Bikeshedding: why not drivers/resctrl to match fs/resctrl? We wouldn't
need the previous patch either to move the arm64 platform drivers.

I'm not an expert on resctrl but the MPAM code looks more like a backend
for the resctrl support, so it makes more sense to do as we did for
other drivers like irqchip, iommu. You can create drivers/resctrl/arm64
if you want to keep them grouped.

-- 
Catalin