diff options
| author | Lorenzo Pieralisi <lpieralisi@kernel.org> | 2024-06-06 11:42:38 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-06-06 16:30:15 +0200 |
| commit | ababa16fd9bd0e2727a1c31c4fb68d6be053bddc (patch) | |
| tree | dd002a2b30d778bdde7e30bd7f9583e34211ed07 /include/linux/acpi.h | |
| parent | d011c022efe275791897668aa421e2db9f2e6450 (diff) | |
irqchip/gic-v3: Enable non-coherent redistributors/ITSes ACPI probing
The GIC architecture specification defines a set of registers for
redistributors and ITSes that control the sharebility and cacheability
attributes of redistributors/ITSes initiator ports on the interconnect
(GICR_[V]PROPBASER, GICR_[V]PENDBASER, GITS_BASER<n>).
Architecturally the GIC provides a means to drive shareability and
cacheability attributes signals but it is not mandatory for designs to
wire up the corresponding interconnect signals that control the
cacheability/shareability of transactions.
Redistributors and ITSes interconnect ports can be connected to
non-coherent interconnects that are not able to manage the
shareability/cacheability attributes; this implicitly makes the
redistributors and ITSes non-coherent observers.
To enable non-coherent GIC designs on ACPI based systems, parse the MADT
GICC/GICR/ITS subtables non-coherent flags to determine whether the
respective components are non-coherent observers and force the
shareability attributes to be programmed into the redistributors and
ITSes registers.
An ACPI global function (acpi_get_madt_revision()) is added to retrieve
the MADT revision, in that it is essential to check the MADT revision
before checking for flags that were added with MADT revision 7 so that
if the kernel is booted with an ACPI MADT table with revision < 7 it
skips parsing the newly added flags (that should be zeroed reserved
values for MADT versions < 7 but they could turn out to be buggy and
should be ignored).
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240606094238.757649-2-lpieralisi@kernel.org
Diffstat (limited to 'include/linux/acpi.h')
| -rw-r--r-- | include/linux/acpi.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 28c3fb2bef0d..000d339e1596 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -279,6 +279,9 @@ static inline bool invalid_phys_cpuid(phys_cpuid_t phys_id) return phys_id == PHYS_CPUID_INVALID; } + +int __init acpi_get_madt_revision(void); + /* Validate the processor object's proc_id */ bool acpi_duplicate_processor_id(int proc_id); /* Processor _CTS control */ |