From 5e89c55e4ed81d7abb1ce8828db35fa389dc0e90 Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Tue, 26 Jan 2016 11:10:38 +0000 Subject: 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 [1] https://acpica.org/sites/acpica/files/MP%20Startup%20for%20ARM%20platforms.docx Signed-off-by: Lorenzo Pieralisi Tested-by: Loc Ho Cc: Will Deacon Cc: Hanjun Guo Cc: Sudeep Holla Cc: Mark Rutland Cc: Mark Salter Cc: Al Stone [catalin.marinas@arm.com: Added WARN_ONCE(!acpi_parking_protocol_valid() on the IPI] Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/arm64/Kconfig') diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 8cc62289a63e..53e48a617fef 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -756,6 +756,15 @@ endmenu menu "Boot options" +config ARM64_ACPI_PARKING_PROTOCOL + bool "Enable support for the ARM64 ACPI parking protocol" + depends on ACPI + help + Enable support for the ARM64 ACPI parking protocol. If disabled + the kernel will not allow booting through the ARM64 ACPI parking + protocol even if the corresponding data is present in the ACPI + MADT table. + config CMDLINE string "Default kernel command string" default "" -- cgit v1.2.3