Re: [Qemu-devel] [qemu PATCH 2/2] arm: add fw_cfg to "virt" board

[Laszlo Ersek <lersek@redhat.com>]

On 11/28/14 00:28, Peter Maydell wrote:
> On 27 November 2014 at 23:18, Laszlo Ersek <lersek@redhat.com> wrote:
>> fw_cfg already supports exposure over MMIO (used in ppc/mac_newworld.c,
>> ppc/mac_oldworld.c, sparc/sun4m.c); we can easily add it to the "virt"
>> board.
>>
>> The mmio register block of fw_cfg is advertized in the device tree. As
>> base address we pick 0x09020000, which conforms to the comment preceding
>> "a15memmap": it falls in the miscellaneous device I/O range 128MB..256MB,
>> and it is aligned at 64KB.
> 
>> +    nodename = g_strdup_printf("/fw-cfg@%" PRIx64, base);
>> +    qemu_fdt_add_subnode(vbi->fdt, nodename);
>> +    qemu_fdt_setprop_string(vbi->fdt, nodename,
>> +                            "compatible", "fw-cfg,mmio");
>> +    qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "reg",
>> +                                 2, base, 2, FW_CFG_SIZE,
>> +                                 2, base + FW_CFG_SIZE, 2, FW_CFG_DATA_SIZE);
>> +    g_free(nodename);
> 
> Are you planning to submit this DT binding to the kernel folks
> as a proper official one (ie documented)? I know the kernel
> doesn't need to read/write it, but the kernel doc tree is
> AFAIK the only place that's actually documenting ARM DT
> bindings right now...

Thanks for the hint, I was actually wondering if some official registry
existed for the node names and types. So yeah I'll attempt to get it in
there. (Once I find the docs in question in the kernel :))

Thanks!
Laszlo