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authorLorenzo Pieralisi <lorenzo.pieralisi@arm.com>2016-01-26 14:10:38 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2016-02-16 18:12:32 +0300
commit5e89c55e4ed81d7abb1ce8828db35fa389dc0e90 (patch)
treecfd0cd4f288fd346ce3b17cbf6c53d128bdfe132 /arch/arm64/include/asm/acpi.h
parent068a17a5805dfbca4bbf03e664ca6b19709cc7a8 (diff)
downloadlinux-5e89c55e4ed81d7abb1ce8828db35fa389dc0e90.tar.xz
arm64: kernel: implement ACPI parking protocol
The SBBR and ACPI specifications allow ACPI based systems that do not implement PSCI (eg systems with no EL3) to boot through the ACPI parking protocol specification[1]. This patch implements the ACPI parking protocol CPU operations, and adds code that eases parsing the parking protocol data structures to the ARM64 SMP initializion carried out at the same time as cpus enumeration. To wake-up the CPUs from the parked state, this patch implements a wakeup IPI for ARM64 (ie arch_send_wakeup_ipi_mask()) that mirrors the ARM one, so that a specific IPI is sent for wake-up purpose in order to distinguish it from other IPI sources. Given the current ACPI MADT parsing API, the patch implements a glue layer that helps passing MADT GICC data structure from SMP initialization code to the parking protocol implementation somewhat overriding the CPU operations interfaces. This to avoid creating a completely trasparent DT/ACPI CPU operations layer that would require creating opaque structure handling for CPUs data (DT represents CPU through DT nodes, ACPI through static MADT table entries), which seems overkill given that ACPI on ARM64 mandates only two booting protocols (PSCI and parking protocol), so there is no need for further protocol additions. Based on the original work by Mark Salter <msalter@redhat.com> [1] https://acpica.org/sites/acpica/files/MP%20Startup%20for%20ARM%20platforms.docx Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Tested-by: Loc Ho <lho@apm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Hanjun Guo <hanjun.guo@linaro.org> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mark Salter <msalter@redhat.com> Cc: Al Stone <ahs3@redhat.com> [catalin.marinas@arm.com: Added WARN_ONCE(!acpi_parking_protocol_valid() on the IPI] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/acpi.h')
-rw-r--r--arch/arm64/include/asm/acpi.h19
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index caafd63b8092..aee323b13802 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -87,9 +87,26 @@ void __init acpi_init_cpus(void);
static inline void acpi_init_cpus(void) { }
#endif /* CONFIG_ACPI */
+#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
+bool acpi_parking_protocol_valid(int cpu);
+void __init
+acpi_set_mailbox_entry(int cpu, struct acpi_madt_generic_interrupt *processor);
+#else
+static inline bool acpi_parking_protocol_valid(int cpu) { return false; }
+static inline void
+acpi_set_mailbox_entry(int cpu, struct acpi_madt_generic_interrupt *processor)
+{}
+#endif
+
static inline const char *acpi_get_enable_method(int cpu)
{
- return acpi_psci_present() ? "psci" : NULL;
+ if (acpi_psci_present())
+ return "psci";
+
+ if (acpi_parking_protocol_valid(cpu))
+ return "parking-protocol";
+
+ return NULL;
}
#ifdef CONFIG_ACPI_APEI