Re: [Resend PATCH 2/5] ACPI/Resource: Add address translation support

From: Bjorn Helgaas
Date: Wed Oct 16 2013 - 19:05:38 EST


On Fri, Oct 11, 2013 at 08:18:58PM +0800, tianyu.lan@xxxxxxxxx wrote:
> From: Lan Tianyu <tianyu.lan@xxxxxxxxx>
>
> According ACPI 5.0 spec Section 19.1.8

This section reference is wrong. Table 5-133 (on page 243) does
point to Section 19.1.8, but that section is only the ASL grammar
description and doesn't have any useful information about what
_TRA means.

A more useful reference (and the source of the quote below) is
Section 6.4.3.5.1.

> "For bridges, translate addresses across the bridge, this 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."

You didn't quote this correctly. Here's a copy/paste from the spec:

For bridges that translate addresses across the bridge, this 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.

> This patch is to add address translation offset to the start/end
> of struct resource in the acpi_dev_resource_address_space().
> Further more, non-bridge device's translation_offset should 0.
> So this change will affect other devices.
>
> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>

I like the patch, though :) With the above corrections,

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

> ---
> drivers/acpi/resource.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
> index 929f416..84bc3db 100644
> --- a/drivers/acpi/resource.c
> +++ b/drivers/acpi/resource.c
> @@ -192,8 +192,8 @@ bool acpi_dev_resource_address_space(struct acpi_resource *ares,
> if (ACPI_FAILURE(status))
> return true;
>
> - res->start = addr.minimum;
> - res->end = addr.maximum;
> + res->start = addr.minimum + addr.translation_offset;
> + res->end = addr.maximum + addr.translation_offset;
> window = addr.producer_consumer == ACPI_PRODUCER;
>
> switch(addr.resource_type) {
> --
> 1.8.2.1
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/