Re: [Qemu-devel] [PATCH v2 2/2] fw_cfg: document MMIO registers for arm, sun4*, and ppc/mac_*

[Peter Maydell]

On 6 August 2015 at 15:49, Gabriel L. Somlo <address@hidden> wrote:
> On Thu, Aug 06, 2015 at 02:15:11PM +0100, Peter Maydell wrote:
>> On 6 August 2015 at 10:14, Laszlo Ersek <address@hidden> wrote:
>> > On 08/06/15 01:47, Gabriel L. Somlo wrote:
>>
>> >> +=== arm Register Locations ===
>> >> +
>> >> +Selector Register MMIO addr: 0x9020008 (16-bit, big-endian)
>> >> +Data Register MMIO addr:     0x9020000 (64-bit)
>> >
>> > Suggestions:
>> > - maybe mention that this is specific to the "virt" machtype
>> > - mention that the exact location comes from the DTB,
>> >   and hint at "Documentation/devicetree/bindings/arm/fw-cfg.txt" in the
>> >   kernel tree
>> > - for the data register, rather than just "(64-bit)", consider saying
>> >   "(64-bit, endianless, string-preserving)"
>>
>> We shouldn't be documenting the specific locations at all --
>> the guest *must* look at the DTB or ACPI table to find the
>> device.
>
> I see how that may work on x86 (acpi) or arm (dtb). But would either of
> those also work for sun4 and ppc/mac ? Do we even care ? ;)

That comment was specifically about ARM, which is why I only
quoted the bit of your patch relating to ARM. I don't know
how ppc and sparc are currently locating the fw_cfg thing.

-- PMM