diff options
| author | Andre Przywara <andre.przywara@arm.com> | 2026-10-01 17:34:36 +0200 |
|---|---|---|
| committer | James Morse <james.morse@arm.com> | 2026-10-02 18:22:55 +0100 |
| commit | 0ef7c5eb77c6cf57582bda2b96a845bdd9e8c9d2 (patch) | |
| tree | 35fb547b22402b43fbf27475f6681098717ccf32 /include/linux | |
| parent | ca539a37d59a65d05538b24406a9ac49869fd86c (diff) | |
arm_mpam: add MPAM-Fb MSC firmware access support
The Arm MPAM Firmware-backed (Fb) Profile document[1] describes an
alternative way of accessing the "Memory System Components" (MSC) in an
MPAM enabled system.
Normally the MSCs are MMIO mapped, but in some implementations this
might not be possible (MSC located outside of the local socket, MSC
mapped secure-only) or desirable (direct MMIO access too slow or needs
to be mediated through a control processor). MPAM-fb standardises a
protocol to abstract MSC accesses, building on the SCMI protocol.
Add functions that do an MSC read or write access by redirecting the
request through a firmware interface. For now this done via an ACPI
PCC shared memory and mailbox combination.
Since the protocol used is only a small subset of the full SCMI spec,
and the SCMI protocol has no full ACPI support anyway, open-code the
(simple) SCMI message generation, for just the fields we need.
[1] https://developer.arm.com/documentation/den0144/latest
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Tested-by: Ritwick Sharma <ritwick.sharma@arm.com> # on Arm AGI CPU
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Srivathsa L Rao <srivathsa.rao@oss.qualcomm.com>
Reviewed-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/arm_mpam.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/arm_mpam.h b/include/linux/arm_mpam.h index f92a36187a52..002f56e15362 100644 --- a/include/linux/arm_mpam.h +++ b/include/linux/arm_mpam.h @@ -12,7 +12,7 @@ struct mpam_msc; enum mpam_msc_iface { MPAM_IFACE_MMIO, /* a real MPAM MSC */ - MPAM_IFACE_PCC, /* a fake MPAM MSC */ + MPAM_IFACE_PCC, /* using the MPAM-Fb firmware redirection */ }; enum mpam_class_types { |