From: Arnd Bergmann <arnd@arndb.de>
To: Hanjun Guo <hanjun.guo@linaro.org>
Cc: linaro-kernel@lists.linaro.org,
Mark Rutland <mark.rutland@arm.com>,
Matthew Garrett <mjg59@srcf.ucam.org>,
"Russell King - ARM Linux" <linux@arm.linux.org.uk>,
Rob Herring <robh@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Olof Johansson <olof@lixom.net>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org,
linux-acpi@vger.kernel.org, patches@linaro.org,
Grant Likely <grant.likely@linaro.org>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-arm-kernel@lists.infradead.org,
Charles.Garcia-Tobin@arm.com
Subject: Re: [PATCH 06/20] ARM64 / ACPI: Introduce some PCI functions when PCI is enabled
Date: Mon, 20 Jan 2014 19:39:52 +0100 [thread overview]
Message-ID: <201401201939.53035.arnd@arndb.de> (raw)
In-Reply-To: <52DD2F23.2010109@linaro.org>
On Monday 20 January 2014, Hanjun Guo wrote:
> >> acpi_register_ioapic()/acpi_unregister_ioapic() will be used for IOAPIC
> >> hotplug and GIC distributor is something like IOAPIC on x86, so I think
> >> these two functions can be reserved for future use.
> > But GIC is not hotplugged, is it? It still sounds x86 specific to me.
>
> Well, if we want to do physical CPU hotplug on ARM/ARM64 (maybe years
> later?),
> then GIC add/remove is needed because we have to remove GIC
> on the SoC too when we remove the physical CPU.
In general, I recommend not planning for the future in kernel code when you
don't know what is going to happen. It's always easy enough to change
things once you get there, as long as no stable ABI is involved.
I just looked at the caller of these functions, and found a self-contained
PCI driver in drivers/pci/ioapic.c, which uses two sepate PCI classes for
ioapic and ioxapic. I think it's a safe assumption to say that even if we
get ARM CPU+GIC hotplug, that would not use the same ioapic driver. This
driver is currently marked X86-only, and that should probably stay this way,
so you won't need the hooks.
Arnd
next prev parent reply other threads:[~2014-01-20 18:40 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-17 12:24 [PATCH 00/20] Make ACPI core running on ARM64 Hanjun Guo
2014-01-17 12:24 ` [PATCH 01/20] ARM64 / ACPI: Make PCI optional for ACPI " Hanjun Guo
2014-01-17 16:00 ` Bjorn Helgaas
2014-01-20 9:33 ` Hanjun Guo
2014-01-17 12:24 ` [PATCH 02/20] ARM64 : Add dummy asm/cpu.h Hanjun Guo
2014-01-17 14:22 ` Sudeep Holla
2014-01-20 8:58 ` Hanjun Guo
2014-01-23 16:15 ` Catalin Marinas
2014-01-24 14:41 ` Hanjun Guo
2014-01-17 12:24 ` [PATCH 03/20] ARM64 / ACPI: Introduce the skeleton of _PDC related for ARM64 Hanjun Guo
[not found] ` <52D93D4E.5020605@arm.com>
2014-01-20 9:20 ` Hanjun Guo
2014-01-23 16:19 ` Catalin Marinas
2014-01-24 14:43 ` Hanjun Guo
2014-01-23 18:03 ` Catalin Marinas
2014-01-24 15:35 ` Hanjun Guo
2014-01-17 12:24 ` [PATCH 04/20] ARM64 / ACPI: Introduce arm_core.c and its related head file Hanjun Guo
2014-01-17 14:12 ` Will Deacon
2014-01-18 4:05 ` Hanjun Guo
[not found] ` <52D960D1.3090700@arm.com>
2014-01-20 12:26 ` Hanjun Guo
2014-01-22 11:54 ` Lorenzo Pieralisi
2014-01-23 15:56 ` [Linaro-acpi] " Tomasz Nowicki
2014-01-24 9:09 ` Hanjun Guo
2014-01-24 12:53 ` Lorenzo Pieralisi
2014-01-24 16:44 ` Tomasz Nowicki
2014-01-17 12:24 ` [PATCH 05/20] ARM64 / ACPI: Introduce lowlevel suspend function Hanjun Guo
2014-01-17 12:25 ` [PATCH 06/20] ARM64 / ACPI: Introduce some PCI functions when PCI is enabled Hanjun Guo
2014-01-17 14:04 ` Arnd Bergmann
2014-01-20 8:08 ` Hanjun Guo
2014-01-20 8:20 ` Arnd Bergmann
2014-01-20 14:13 ` Hanjun Guo
2014-01-20 18:39 ` Arnd Bergmann [this message]
2014-01-21 3:40 ` Hanjun Guo
2014-01-17 12:25 ` [PATCH 07/20] ARM64 / ACPI: Enable ARM64 in Kconfig Hanjun Guo
[not found] ` <52D93F88.8090801@arm.com>
2014-01-20 9:30 ` Hanjun Guo
2014-01-23 16:39 ` Catalin Marinas
2014-01-24 14:45 ` Hanjun Guo
2014-01-17 12:25 ` [PATCH 08/20] ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 Hanjun Guo
2014-01-17 12:25 ` [PATCH 09/20] ARM64 / ACPI: Implement core functions for parsing MADT table Hanjun Guo
2014-01-17 14:12 ` Arnd Bergmann
2014-01-20 8:49 ` Hanjun Guo
2014-01-23 17:54 ` Marc Zyngier
2014-01-24 15:34 ` Hanjun Guo
2014-01-24 20:57 ` Arnd Bergmann
2014-01-17 12:25 ` [PATCH 10/20] ARM64 / ACPI: Enumerate possible/present CPU set and map logical cpu id to APIC id Hanjun Guo
2014-01-17 17:37 ` Sudeep Holla
2014-01-20 14:00 ` Hanjun Guo
2014-01-22 15:53 ` Lorenzo Pieralisi
2014-01-24 14:37 ` Hanjun Guo
2014-01-24 15:35 ` Lorenzo Pieralisi
2014-01-24 16:02 ` Hanjun Guo
2014-01-17 12:25 ` [PATCH 11/20] ARM64 / ACPI: Get the enable method for SMP initialization Hanjun Guo
2014-01-23 17:50 ` Catalin Marinas
2014-01-24 14:57 ` Hanjun Guo
2014-01-17 12:25 ` [PATCH 12/20] ARM64 / ACPI: Use Parked Address in GIC structure for spin table SMP initialisation Hanjun Guo
2014-01-17 14:15 ` Arnd Bergmann
2014-01-17 14:35 ` Tomasz Nowicki
2014-01-17 12:25 ` [PATCH 13/20] ARM64 / ACPI: Define ACPI_IRQ_MODEL_GIC needed for arm Hanjun Guo
2014-01-17 12:25 ` [PATCH 14/20] Irqchip / gic: Set as default domain so we can access from ACPI Hanjun Guo
2014-01-17 12:25 ` [PATCH 15/20] ACPI / ARM64: Update acpi_register_gsi to register with the core IRQ subsystem Hanjun Guo
2014-01-17 12:25 ` =?yes?q?=5BPATCH=2016/20=5D=20ACPI=20/=20GIC=3A=20Initialize=20GIC=20using=20the=20information=20in=20MADT?= Hanjun Guo
2014-01-17 12:25 ` [PATCH 17/20] clocksource / arch_timer: Use ACPI GTDT table to initialize arch timer Hanjun Guo
2014-01-27 11:26 ` Mark Rutland
2014-01-17 12:25 ` [PATCH 18/20] clocksource / acpi: Add macro CLOCKSOURCE_ACPI_DECLARE Hanjun Guo
2014-01-17 14:21 ` Arnd Bergmann
2014-01-20 9:08 ` Hanjun Guo
2014-01-22 11:46 ` Mark Rutland
2014-01-22 14:56 ` Arnd Bergmann
2014-01-22 15:17 ` Mark Rutland
2014-01-22 15:47 ` Arnd Bergmann
2014-01-24 9:19 ` Hanjun Guo
2014-01-24 0:46 ` Hanjun Guo
2014-01-22 8:26 ` Linus Walleij
2014-01-22 11:45 ` Mark Rutland
2014-01-22 14:38 ` Linus Walleij
2014-01-24 0:20 ` Hanjun Guo
2014-01-24 12:08 ` Mark Rutland
2014-01-24 15:15 ` Catalin Marinas
2014-01-24 15:44 ` Mark Rutland
2014-01-24 15:53 ` Hanjun Guo
2014-01-24 0:12 ` Hanjun Guo
2014-01-24 12:32 ` Mark Rutland
2014-01-24 15:45 ` Hanjun Guo
2014-01-17 12:25 ` [PATCH 19/20] clocksource / ACPI: Introduce clocksource_acpi_init() using CLOCKSOURCE_ACPI_DECLARE Hanjun Guo
2014-01-17 12:25 ` [PATCH 20/20] ARM64 / clocksource: Use clocksource_acpi_init() Hanjun Guo
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