Re: [PATCH 06/20] ARM64 / ACPI: Introduce some PCI functions whenPCI is enabled

From: Hanjun Guo
Date: Mon Jan 20 2014 - 09:14:31 EST

On 2014å01æ20æ 16:20, Arnd Bergmann wrote:
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)
+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;
+int acpi_unregister_ioapic(acpi_handle handle, u32 gsi_base)
+ /* TBD */
+ return -EINVAL;
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 ;-)

me too :)

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

ok, that would be make sense, will update it in next version.

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.

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