Re: [PATCH V3 18/21] ACPI, PCI: Refine the way to handle translation_offset for ACPI resources

From: Hanjun Guo
Date: Thu Jan 28 2016 - 05:23:43 EST

Hi Lorenzo,

On 2016/1/19 20:20, Lorenzo Pieralisi wrote:

On Wed, Jan 13, 2016 at 02:21:04PM +0100, Tomasz Nowicki wrote:
From: Liu Jiang <jiang.liu@xxxxxxxxxxxxxxx>

Some architectures, such as IA64 and ARM64, have no instructions to
directly access PCI IO ports, so they map PCI IO ports into PCI MMIO
address space. Typically PCI host bridges on those architectures take
the responsibility to map (translate) PCI IO port transactions into
Memory-Mapped IO transactions. ACPI specification provides support
of such a usage case by using resource translation_offset.

But current ACPI resource parsing interface isn't neutral enough,
it still has some special logic for IA64. So refine the ACPI resource
parsing interface and IA64 code to neutrally handle translation_offset
1) ACPI resource parsing interface doesn't do any translation, it just
save the translation_offset to be used by arch code.
2) Arch code will do the mapping(translation) based on arch specific
information. Typically it does:
2.a) Translate per PCI domain IO port address space into system global
IO port address space.
2.b) Setup MMIO address mapping for IO ports.

This patch fixes IO space handling on IA64 and should go in as a fix.

IA64 PCI IO space is currently broken (Hanjun tested this on an IA64 box).

The first broken commit is:

3772aea7d6f3 ("ia64/PCI/ACPI: Use common ACPI resource parsing interface for host bridge")

because acpi core code checks (in acpi_dev_ioresource_flags()) the
resource.end>=0x10003, which fails on ia64 - currently resource.end is
set in acpi_decode_space() to:

AddressMaximum + AddressTranslation

where AddressTranslation is the CPU physical address mapping IO space
on IA64, the >=0x10003 check in acpi_dev_ioresource_flags always
triggers and the IO resource is then disabled.

Do you want me to re-send this patch as a fix, with updated commit log ?

I talked to Gerry offline, he is busy these days, he said it's pretty
OK for you to resend this patch and fix the problem.