From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH v3] ARM64: kernel: implement ACPI parking protocol Date: Tue, 2 Feb 2016 18:26:58 +0000 Message-ID: <20160202182657.GC15706@e104818-lin.cambridge.arm.com> References: <1453806638-23167-1-git-send-email-lorenzo.pieralisi@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.101.70]:57777 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756784AbcBBS1C (ORCPT ); Tue, 2 Feb 2016 13:27:02 -0500 Content-Disposition: inline In-Reply-To: <1453806638-23167-1-git-send-email-lorenzo.pieralisi@arm.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lorenzo Pieralisi Cc: linux-arm-kernel@lists.infradead.org, Mark Rutland , Mark Salter , Will Deacon , linux-acpi@vger.kernel.org, Hanjun Guo , Sudeep Holla , Al Stone , Loc Ho On Tue, Jan 26, 2016 at 11:10:38AM +0000, Lorenzo Pieralisi wrote: > 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 > Cc: Will Deacon > Cc: Hanjun Guo > Cc: Loc Ho > Cc: Sudeep Holla > Cc: Catalin Marinas > Cc: Mark Rutland > Cc: Mark Salter > Cc: Al Stone Applied, with a minor addition just to warn people from not using it in other configurations (#ifdef still needed otherwise the acpi_parking_protocol_valid symbol is not available; but I prefer uglier code than people starting to use this IPI in their firmware): --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -767,6 +767,12 @@ void handle_IPI(int ipinr, struct pt_regs *regs) break; #endif + +#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL case IPI_WAKEUP: + WARN_ONCE(!acpi_parking_protocol_valid(cpu), + "CPU%u: Wake-up IPI outside the ACPI parking protocol\n", + cpu); break; +#endif default: Thanks. -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Tue, 2 Feb 2016 18:26:58 +0000 Subject: [PATCH v3] ARM64: kernel: implement ACPI parking protocol In-Reply-To: <1453806638-23167-1-git-send-email-lorenzo.pieralisi@arm.com> References: <1453806638-23167-1-git-send-email-lorenzo.pieralisi@arm.com> Message-ID: <20160202182657.GC15706@e104818-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Jan 26, 2016 at 11:10:38AM +0000, Lorenzo Pieralisi wrote: > 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 > Cc: Will Deacon > Cc: Hanjun Guo > Cc: Loc Ho > Cc: Sudeep Holla > Cc: Catalin Marinas > Cc: Mark Rutland > Cc: Mark Salter > Cc: Al Stone Applied, with a minor addition just to warn people from not using it in other configurations (#ifdef still needed otherwise the acpi_parking_protocol_valid symbol is not available; but I prefer uglier code than people starting to use this IPI in their firmware): --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -767,6 +767,12 @@ void handle_IPI(int ipinr, struct pt_regs *regs) break; #endif + +#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL case IPI_WAKEUP: + WARN_ONCE(!acpi_parking_protocol_valid(cpu), + "CPU%u: Wake-up IPI outside the ACPI parking protocol\n", + cpu); break; +#endif default: Thanks. -- Catalin