From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH v3] ARM64: kernel: implement ACPI parking protocol Date: Wed, 3 Feb 2016 16:18:36 +0000 Message-ID: <20160203161834.GB26487@MBP.local> References: <1453806638-23167-1-git-send-email-lorenzo.pieralisi@arm.com> <20160202182657.GC15706@e104818-lin.cambridge.arm.com> <20160203112112.GA18387@red-moon> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.101.70]:35292 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932397AbcBCQSn (ORCPT ); Wed, 3 Feb 2016 11:18:43 -0500 Content-Disposition: inline In-Reply-To: <20160203112112.GA18387@red-moon> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lorenzo Pieralisi Cc: Mark Rutland , Sudeep Holla , Will Deacon , linux-acpi@vger.kernel.org, Hanjun Guo , Mark Salter , Al Stone , linux-arm-kernel@lists.infradead.org, Loc Ho On Wed, Feb 03, 2016 at 11:21:12AM +0000, Lorenzo Pieralisi wrote: > On Tue, Feb 02, 2016 at 06:26:58PM +0000, Catalin Marinas wrote: > > 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): > > It makes sense, we could include asm/acpi.h in smp.c (which is not > included by linux/acpi.h if !CONFIG_ACPI) to pull in the symbol and > remove the ifdef if you think it is cleaner. I don't think it's worth. BTW, the acpi_parking_protocol_valid() definition has an __init annotation while the declaration does not. I removed the __init altogether since I get a section mismatch warning when being called from handle_IPI. -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Wed, 3 Feb 2016 16:18:36 +0000 Subject: [PATCH v3] ARM64: kernel: implement ACPI parking protocol In-Reply-To: <20160203112112.GA18387@red-moon> References: <1453806638-23167-1-git-send-email-lorenzo.pieralisi@arm.com> <20160202182657.GC15706@e104818-lin.cambridge.arm.com> <20160203112112.GA18387@red-moon> Message-ID: <20160203161834.GB26487@MBP.local> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Feb 03, 2016 at 11:21:12AM +0000, Lorenzo Pieralisi wrote: > On Tue, Feb 02, 2016 at 06:26:58PM +0000, Catalin Marinas wrote: > > 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): > > It makes sense, we could include asm/acpi.h in smp.c (which is not > included by linux/acpi.h if !CONFIG_ACPI) to pull in the symbol and > remove the ifdef if you think it is cleaner. I don't think it's worth. BTW, the acpi_parking_protocol_valid() definition has an __init annotation while the declaration does not. I removed the __init altogether since I get a section mismatch warning when being called from handle_IPI. -- Catalin