Hi Magnus,
On Tue, Mar 21, 2017 at 8:17 AM, Magnus Damm <magnus.damm@xxxxxxxxx> wrote:
> On Mon, Mar 20, 2017 at 7:57 PM, Geert Uytterhoeven
> <geert@xxxxxxxxxxxxxx> wrote:
>> On Mon, Mar 20, 2017 at 9:49 AM, Magnus Damm <magnus.damm@xxxxxxxxx> wrote:
>>> --- 0001/arch/arm64/boot/dts/renesas/r8a7795.dtsi
>>> +++ work/arch/arm64/boot/dts/renesas/r8a7795.dtsi 2017-03-20 17:41:36.390607110 +0900
>>> @@ -1209,7 +1209,7 @@
>>>
>>> sata: sata@ee300000 {
>>> compatible = "renesas,sata-r8a7795";
>>> - reg = <0 0xee300000 0 0x1fff>;
>>> + reg = <0 0xee300000 0 0x200000>;
>>
>> While the datasheet does mention the 2 MiB area, it also says no (write)
>> access should be made to registers not listed in the table, while these are
>> all covered by the existing area?
>
> That bit about not writing to non-listed registers seems like just
> common sense to me, but perhaps there is more to the story than just
Sure.
> that? Like you say it is probably possible to use the driver with the
> existing 8K-1 size, but in my mind we should use window sizes defined
> in the data sheet for DT?
The 2 MiB window size is a lot larger than needed to cover all documented
rregisters. Either there are more undocumented registers, or the hardware
engineers were lazy and just decoded the full 2 MiB block.
>> BTW, what about the Reference Clock Source Select Register, which lies
>> in a further undocumented area?
>
> Yeah, no idea. This would be good task for the I/O or Core group to
SATA is I/O.
> figure out how to handle. I'm surprised that the SATA DT device nodes
> with the strange and incorrect 0x1fff size got merged upstream without
> anyone thinking about that register that you are mentioning. Seems
> like supporting that should be part of SATA development for R-Car
> Gen3?
Probably it was just an oversight. I almost missed it myself when
reviewing your patch.
The register is not present (not documented) on R-Car H1 and Gen2.
The IP core is derived from SH-Navi2G (sh7775), but no datasheet.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
