[PATCH 1/2 v5] arm: kirkwood: add dreamplug (fdt) support.

[Grant Likely]

On Thu, Feb 23, 2012 at 2:11 PM, Jason <jason at lakedaemon.net> wrote:
> On Thu, Feb 23, 2012 at 01:18:55PM -0700, Grant Likely wrote:
>> On Thu, Feb 23, 2012 at 12:52 PM, Jason Cooper <jason at lakedaemon.net> wrote:
>> > Initially, copied guruplug-setup.c and did s/guruplug/dreamplug/g.
>> > Then, switched to SPI based NOR flash.
>> >
>> > After talking to Arnd Bergman, chose an incremental approach to adding
>> > devicetree support.  First, we use the dtb to tell us we are on the
>> > dreamplug, then we gradually port over drivers.
>> >
>> > Driver porting will start with the uart (see next patch), and progress
>> > from there.  Possibly, spi/flash/partitions will be next.
>> >
>> > When done, board-dt.c will no longer be dreamplug specific, and dt's can
>> > be made for the other kirkwood boards.
>> >
>> > Signed-off-by: Jason Cooper <jason at lakedaemon.net>
>> > ---
>> > Changes from v1
>> >
>> >   - attempting dts, looking for pointers.
>> >
>> > Changes from v2
>> >
>> >   - resubmit as MACH_TYPE_DREAMPLUG (3550) is in arm/for-next, rebased
>> >     against same.
>> >   - removed lame fdt attempt, others are working on kirkwood fdt.  Will
>> >     convert once kirkwood fdt is mainline.
>> >   - s/boot_params/atag_offset/
>> >   - added kirkwood_reset
>> >   - 1 checkpatch.pl warning (help in Kconfig), looks the same as all
>> >     other kirkwood boards...
>> >
>> > Changes from v3
>> >
>> >   - rebased against v3.3-rc3 (recommended by Arnd)
>> >   - use devicetree to determine which board we are on
>> >   - added patch to configure uart0 from devicetree
>> >
>> > Changes from v4
>> >
>> >   - fixed Kconfig logic so user can always see 'Dreamplug' in menuconfig.
>> >   - changed 'marvell,dreamplug' to 'globalscale,dreamplug' as suggested by
>> >     Grant Likely.
>> >   - fixed of_machine_is_compatible() logic for calling dreamplug specific
>> >     init functions.
>> >
>> >  arch/arm/boot/dts/kirkwood-dreamplug.dts |   18 +++
>> >  arch/arm/boot/dts/kirkwood.dtsi          |    6 +
>> >  arch/arm/mach-kirkwood/Kconfig           |   14 +++
>> >  arch/arm/mach-kirkwood/Makefile          |    1 +
>> >  arch/arm/mach-kirkwood/Makefile.boot     |    2 +
>> >  arch/arm/mach-kirkwood/board-dt.c        |  182 ++++++++++++++++++++++++++++++
>> >  6 files changed, 223 insertions(+), 0 deletions(-)
>> >  create mode 100644 arch/arm/boot/dts/kirkwood-dreamplug.dts
>> >  create mode 100644 arch/arm/boot/dts/kirkwood.dtsi
>> >  create mode 100644 arch/arm/mach-kirkwood/board-dt.c
>> >
>> > diff --git a/arch/arm/boot/dts/kirkwood-dreamplug.dts b/arch/arm/boot/dts/kirkwood-dreamplug.dts
>> > new file mode 100644
>> > index 0000000..765813f
>> > --- /dev/null
>> > +++ b/arch/arm/boot/dts/kirkwood-dreamplug.dts
>> > @@ -0,0 +1,18 @@
>> > +/dts-v1/;
>> > +
>> > +/include/ "kirkwood.dtsi"
>> > +
>> > +/ {
>> > +       model = "Globalscale Technologies Dreamplug";
>> > +       compatible = "globalscale,dreamplug", "globalscale,kirkwood";
>>
>> Hahaha... okay, more clarification is needed here.
>>
>> The compatible property is a list, and the first entry must always be
>> the exact device model.  That is why the vendor of the hardware is in
>> the prefix.  However, the following entries are a list of devices that
>> it is 'compatible' with.  In the case of the top-level compatible
>> property, we've been using the convention of including a string for
>> the SoC, and in that case the manufacturer is indeed Marvell.
>>
>> Also, *be specific*.  Kirkwood is a family of processors, not a single
>> SoC.  The compatible string should reflect that.  So, in your case,
>> compatible should look something like:
>>
>> compatible = "globalscale,dreamplug", "marvell,kirkwood-88f6281";
>
> ahhh... ok.  So, my board-dt.c should have:
>
> static const char *kirkwood_dt_board_compat[] = {
>        "marvell,kirkwood",
>        NULL
> };
>
> And then the test to run the dreamplug specific init should be:
>
>        if (of_machine_is_compatible("globalscale,dreamplug"))
>                dreamplug_init();
>
> And then, kirkwood.dtsi:
>
> compatible = "marvell,kirkwood";
>
> and kirkwood-dreamplug.dts:
>
> compatible = "globalscale,dreamplug", "marvell,kirkwood-88f6281-a1";
>
>
> My only question is, should the kirkwood.dtsi have just
> "marvell,kirkwood", or "marvell,kirkwood","marvell,kirkwood-88f6281-a1"?

Fix the order.  The list is ordered from most specific to least.
Also, if the silicon revision can be read out of the SoC at runtime,
then including the -a1 revision is probably overkill.

So, something like the following is fine:

compatible = "globalscale,dreamplug", "marvell,kirkwood-88f6281",
"marvell,kirkwood";

BTW, does the dreamplug have a part number?

>
> I'm guessing kirkwood.dtsi is a generic devicetree, and should just be
> "marvell,kirkwood".  If that's true, then *kirkwood_dt_board_compat
> should just be "marvell,kirkwood" since board-dt.c should be able to
> handle any kirkwood SoC.
>
> Sorry for being so dense.
>
> thx,
>
> Jason.



-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.