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Message-ID: <54BF3AD5.4070600@linux.intel.com>
Date: Wed, 21 Jan 2015 13:36:21 +0800
From: Jiang Liu <jiang.liu@...ux.intel.com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
CC: Thomas Gleixner <tglx@...utronix.de>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Yinghai Lu <yinghai@...nel.org>,
Borislav Petkov <bp@...en8.de>, Len Brown <lenb@...nel.org>,
Tony Luck <tony.luck@...el.com>, x86@...nel.org,
linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
linux-acpi@...r.kernel.org
Subject: Re: [RFC Patch 14/19] ACPI: Translate resource into master side address
for bridge window resources
On 2015/1/21 8:50, Rafael J. Wysocki wrote:
> On Thursday, January 08, 2015 10:33:01 AM Jiang Liu wrote:
>> Add translation_offset into the result address for bridge window
>> resources to form the master side address.
>>
>> Currently acpi_dev_resource_{ext_}address_space() are only used for
>> devices instead of bridges, so it won't break current users. Later
>> it will be used to support PCI host bridge drivers.
>>
>> Signed-off-by: Jiang Liu <jiang.liu@...ux.intel.com>
>> ---
>> drivers/acpi/resource.c | 14 ++++++++++++++
>> 1 file changed, 14 insertions(+)
>>
>> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
>> index d3aa56674bd4..16d334a1ee25 100644
>> --- a/drivers/acpi/resource.c
>> +++ b/drivers/acpi/resource.c
>> @@ -203,6 +203,20 @@ static bool acpi_decode_space(struct resource *res, resource_size_t *offset,
>> res->start = addr->minimum;
>> res->end = addr->maximum;
>>
>> + /*
>> + * For bridges that translate addresses across the bridge,
>> + * translation_offset is the offset that must be added to the
>> + * address on the secondary side to obtain the address on the
>> + * primary side. Non-bridge devices must list 0 for all Address
>> + * Translation offset bits.
>> + */
>> + if (base->producer_consumer == ACPI_PRODUCER) {
>
> OK, so the assumption is that this check is never true in the current code, right?
Yes.
>
>> + res->start += addr->translation_offset;
>> + res->end += addr->translation_offset;
>> + } else if (addr->translation_offset) {
>
> And won't this break anything even if so?
I'm trying to follow the spec, how about giving a warning here
instead of failure?
Regards!
Gerry
>
>> + return false;
>> + }
>> +
>> switch(base->resource_type) {
>> case ACPI_MEMORY_RANGE:
>> acpi_dev_memresource_flags(res, len, wp);
>>
>
--
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