Re: [Qemu-devel] [kernel PATCH v2 2/2] devicetree: document ARM bindings for QEMU's Firmware Config interface

[Peter Maydell]

On 5 December 2014 at 19:04, Laszlo Ersek <address@hidden> wrote:
> On 12/05/14 19:57, Peter Maydell wrote:
>> On 30 November 2014 at 16:51, Laszlo Ersek <address@hidden> wrote:
>>> +Example:
>>> +
>>> +/ {
>>> +       #size-cells = <0x2>;
>>> +       #address-cells = <0x2>;
>>> +
>>> +       address@hidden {
>>> +               compatible = "qemu,fw-cfg-mmio";
>>> +               reg = <0x0 0x9020000 0x0 0x1000>;
>>> +       };
>>
>> I've just noticed that this example claims a register
>> region size of 0x1000. This seems wrong, because the
>> underlying device doesn't have a register range that
>> big. Surely this should be a size of 0x3 ?
>
> Arnd said I should round up the region to 0x1000.

Right; I replied here as a reasonable place to do so
on an email with the device-tree folk in cc.

> http://thread.gmane.org/gmane.linux.drivers.devicetree/101173/focus=101176

Arnd, what was your reasoning in requesting the round-up?
I would have expected that a dtb with an overlarge range
is telling the guest it can access things that in fact
just aren't there (ie the equivalent of unmapped space which
on h/w would give you an external abort/decode error).

> If that's incorrect I'd prefer to post incremental patches, because 4
> other series already depend on this kernel docs patch.

Docs patches aren't hard dependencies :-)

-- PMM