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SubjectRe: [Patch v5 1/6] ACPI/PCI: Enhance ACPI core to support sparse IO space
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On 2015/7/30 4:37, Bjorn Helgaas wrote:
> On Tue, Jun 09, 2015 at 12:20:43AM +0800, Jiang Liu wrote:
>> Enhance ACPI resource parsing interfaces to support sparse IO space,
>> which will be used to share common code between x86 and IA64 later.
>>
>> Tested-by: Tony Luck <tony.luck@intel.com>
>> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
>> Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
>> ---
>> drivers/acpi/resource.c | 9 ++++++---
>> include/linux/ioport.h | 1 +
>> 2 files changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
>> index 8244f013f210..fdcc73dad2c1 100644
>> --- a/drivers/acpi/resource.c
>> +++ b/drivers/acpi/resource.c
>> @@ -123,7 +123,7 @@ bool acpi_dev_resource_memory(struct acpi_resource *ares, struct resource *res)
>> EXPORT_SYMBOL_GPL(acpi_dev_resource_memory);
>>
>> static void acpi_dev_ioresource_flags(struct resource *res, u64 len,
>> - u8 io_decode)
>> + u8 io_decode, u8 translation_type)
>> {
>> res->flags = IORESOURCE_IO;
>>
>> @@ -135,6 +135,8 @@ static void acpi_dev_ioresource_flags(struct resource *res, u64 len,
>>
>> if (io_decode == ACPI_DECODE_16)
>> res->flags |= IORESOURCE_IO_16BIT_ADDR;
>> + if (translation_type == ACPI_SPARSE_TRANSLATION)
>> + res->flags |= IORESOURCE_IO_SPARSE;
>> }
>>
>> static void acpi_dev_get_ioresource(struct resource *res, u64 start, u64 len,
>> @@ -142,7 +144,7 @@ static void acpi_dev_get_ioresource(struct resource *res, u64 start, u64 len,
>> {
>> res->start = start;
>> res->end = start + len - 1;
>> - acpi_dev_ioresource_flags(res, len, io_decode);
>> + acpi_dev_ioresource_flags(res, len, io_decode, 0);
>> }
>>
>> /**
>> @@ -227,7 +229,8 @@ static bool acpi_decode_space(struct resource_win *win,
>> acpi_dev_memresource_flags(res, len, wp);
>> break;
>> case ACPI_IO_RANGE:
>> - acpi_dev_ioresource_flags(res, len, iodec);
>> + acpi_dev_ioresource_flags(res, len, iodec,
>> + addr->info.io.translation_type);
>> break;
>> case ACPI_BUS_NUMBER_RANGE:
>> res->flags = IORESOURCE_BUS;
>> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
>> index 388e3ae94f7a..24bea087e7af 100644
>> --- a/include/linux/ioport.h
>> +++ b/include/linux/ioport.h
>> @@ -94,6 +94,7 @@ struct resource {
>> /* PnP I/O specific bits (IORESOURCE_BITS) */
>> #define IORESOURCE_IO_16BIT_ADDR (1<<0)
>> #define IORESOURCE_IO_FIXED (1<<1)
>> +#define IORESOURCE_IO_SPARSE (1<<2)
>
> I don't really like this bit. We adding a new generic IORESOURCE_* bit
> just for a special case, and it's only used in one place, for one arch,
> during enumeration.
Hi Bjorn,
Instead of defining a formal flag IORESOURCE_IO_SPARSE, we may
reuse other field in struct resource to pass back the SPARSE flag,
but that's a little dirty. For example, we may reuse res->name field
to carry the SPARSE flag for the IA64 special case.
Is that OK?
Thanks!
Gerry

>
> Don't we have a similar problem (struct resource can't express all the
> information from an ACPI resource) for the _TRA value for bridge windows?
> If it's a similar issue, we should solve it in a similar way.
Per my understanding, we just ignore ACPI address space information
which can't be expressed by struct resource.
Thanks!
Gerry

>
>> /* PCI ROM control bits (IORESOURCE_BITS) */
>> #define IORESOURCE_ROM_ENABLE (1<<0) /* ROM is enabled, same as PCI_ROM_ADDRESS_ENABLE */
>> --
>> 1.7.10.4
>>


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