From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Mon, 20 Jan 2014 09:20:49 +0100
Subject: [PATCH 06/20] ARM64 / ACPI: Introduce some PCI functions when PCI
 is enabled
In-Reply-To: <52DCD961.70303@linaro.org>
References: <1389961514-13562-1-git-send-email-hanjun.guo@linaro.org>
 <201401171504.24525.arnd@arndb.de> <52DCD961.70303@linaro.org>
Message-ID: <4387274.ri38HmFxAV@wuerfel>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Monday 20 January 2014 16:08:01 Hanjun Guo wrote:
> >> diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c
> >> index 3c8521d..1835b21 100644
> >> --- a/drivers/acpi/plat/arm-core.c
> >> +++ b/drivers/acpi/plat/arm-core.c
> >> @@ -100,6 +100,25 @@ int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
> >>  }
> >>  EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
> >>  
> >> +int acpi_isa_irq_to_gsi(unsigned isa_irq, u32 *gsi)
> >> +{
> >> +    return -1;
> >> +}
> >> +
> >> +int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base)
> >> +{
> >> +    /* TBD */
> >> +    return -EINVAL;
> >> +}
> >> +EXPORT_SYMBOL(acpi_register_ioapic);
> >> +
> >> +int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base)
> >> +{
> >> +    /* TBD */
> >> +    return -EINVAL;
> >> +}
> >> +EXPORT_SYMBOL(acpi_unregister_ioapic);
> >> +
> > 
> > My feeling is that these are better handled in the ACPI code by not
> > calling them on architectures that have no ISA or no IOAPIC support.
> > 
> > We have configuration symbols for both, so you don't have to make
> > it depend on CONFIG_ARM64 or CONFIG_X86.
> 
> Do you mean introduce a stub function when there is no ISA support?

Do you anticipate ISA devices on ARM64? I hope not ;-)

My guess is that whatever code calls this function should be disabled
in reduced hw mode.

> 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.

	Arnd