linux-kernel - Re: [PATCH v2 09/18] ACPI / processor: Make it possible to get CPU hardware ID via GICC

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Date:	Wed, 20 Aug 2014 15:56:54 +0100
From:	Catalin Marinas <catalin.marinas@....com>
To:	Hanjun Guo <hanjun.guo@...aro.org>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Mark Rutland <Mark.Rutland@....com>,
	"graeme.gregory@...aro.org" <graeme.gregory@...aro.org>,
	Arnd Bergmann <arnd@...db.de>, Olof Johansson <olof@...om.net>,
	"grant.likely@...aro.org" <grant.likely@...aro.org>,
	Sudeep Holla <Sudeep.Holla@....com>,
	Will Deacon <Will.Deacon@....com>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <Marc.Zyngier@....com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Mark Brown <broonie@...nel.org>, Rob Herring <robh@...nel.org>,
	Robert Richter <rric@...nel.org>,
	Lv Zheng <lv.zheng@...el.com>,
	Robert Moore <robert.moore@...el.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Liviu Dudau <Liviu.Dudau@....com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Charles Garcia-Tobin <Charles.Garcia-Tobin@....com>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linaro-acpi@...ts.linaro.org" <linaro-acpi@...ts.linaro.org>
Subject: Re: [PATCH v2 09/18] ACPI / processor: Make it possible to get CPU
 hardware ID via GICC

On Tue, Aug 19, 2014 at 09:37:34AM +0100, Hanjun Guo wrote:
> On 2014-8-18 22:27, Catalin Marinas wrote:
> > On Mon, Aug 04, 2014 at 04:28:16PM +0100, Hanjun Guo wrote:
> >> diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
> >> index e32321c..4007313 100644
> >> --- a/drivers/acpi/processor_core.c
> >> +++ b/drivers/acpi/processor_core.c
> >> @@ -64,6 +64,38 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
> >>  	return 0;
> >>  }
> >>  
> >> +/*
> >> + * On ARM platform, MPIDR value is the hardware ID as apic ID
> >> + * on Intel platforms
> >> + */
> >> +static int map_gicc_mpidr(struct acpi_subtable_header *entry,
> >> +		int device_declaration, u32 acpi_id, int *mpidr)
> >> +{
> >> +	struct acpi_madt_generic_interrupt *gicc =
> >> +	    container_of(entry, struct acpi_madt_generic_interrupt, header);
> >> +
> >> +	if (!(gicc->flags & ACPI_MADT_ENABLED))
> >> +		return -ENODEV;
> >> +
> >> +	/* In the GIC interrupt model, logical processors are
> >> +	 * required to have a Processor Device object in the DSDT,
> >> +	 * so we should check device_declaration here
> >> +	 */
> >> +	if (device_declaration && (gicc->uid == acpi_id)) {
> >> +		/*
> >> +		 * Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2
> >> +		 * and bits [32:39] Aff3 are meaningful, so pack the Affx
> >> +		 * fields into a single 32 bit identifier to accommodate the
> >> +		 * acpi processor drivers.
> >> +		 */
> >> +		*mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8)
> >> +			 | gicc->arm_mpidr;
> > 
> > You can use pack_mpidr_into_32_bits().
> 
> processor_core.c will be used by x86 and ia64 too, it will cause
> compile error on !ARM64 platforms.

Oh. So we do we have an ARM-specific function in core ACPI code?

-- 
Catalin
--
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