[U-Boot] [PATCH v2 5/7] Tegra30: Cardhu: Add DT files

Tom Warren
2012-12-04T20:29:08Z

Simon,

On Mon, Dec 3, 2012 at 6:01 PM, Simon Glass <sjg@chromium.org> wrote:
> Hi Stephen,
>
> On Mon, Dec 3, 2012 at 4:57 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>> On 12/03/2012 05:49 PM, Simon Glass wrote:
>>> Hi Stephen,
>>>
>>> On Mon, Dec 3, 2012 at 4:40 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>>> On 12/03/2012 04:45 PM, Tom Warren wrote:
>>>>> These are stripped down for bringup, They'll be filled out later
>>>>> to match-up with the kernel DT contents, and/or as devices are
>>>>> brought up (mmc, usb, spi, etc.).
>>>>>
>>>>> Signed-off-by: Tom Warren <twarren@nvidia.com>
>>>>
>>>>> diff --git a/arch/arm/dts/tegra30.dtsi b/arch/arm/dts/tegra30.dtsi
>>>>
>>>>> +/ {
>>>>> + model = "NVIDIA Tegra30";
>>>>
>>>> We don't really need a model property here, but it's not a big deal.
>>>
>>> We do actually use it in U-Boot (in ARM patches on the mailing list).
>>
>> Hmmm. The tegra20.dtsi file doesn't have one...
>
> No problem, then it won't display a model.

Actually, every other build (T20) has the model declared in the .dts
file. Stephen is correct that T30 has it in the .dtsi file, too (not
sure why - another artifact of our internal repo), so removing it will
bring it in line with all the other Tegra builds, and (I assume) will
still display a model name.

>
>>
>>>>> diff --git a/board/nvidia/dts/tegra30-cardhu.dts b/board/nvidia/dts/tegra30-cardhu.dts
>>>>
>>>>> +/memreserve/ 0x1c000000 0x04000000;
>>>>
>>>> /memreserve/ isn't correct for U-Boot; no memory should be reserved.
>>>
>>> But don't we want to use the same fdt for U-Boot as the kernel?
>>
>> The only reason for a memreserve are:
>>
>> a) To reserve the current display frame-buffer. This is a run-time thing
>> that U-Boot should add to the DTB itself, not pre-populated in the DT.
>>
>> b) To reserve memory for some kind of co-processor. We shouldn't be
>> using memreserve for this any more, but rather allocating the memory
>> dynamically in the kernel.
>>
>> So irrespective of the answer to your question we should still remove this.
>>
>> Re: your question: Perhaps, but we're so far away from that right now,
>> it almost doesn't seem worth caring yet. Also, while we should certainly
>> use the same bindings, I'm not sure we should use the same actual .dtb
>> file bitstream, since the .dtb passed to the kernel should be loaded
>> from the filesystem/... where the kernel zImage was, not embedded into
>> the bootloader.
>
> I don't really mind, but I hold fond hopes of using the same source
> for each at some point. Not an issue for now.

Note that the only Tegra20 build that has a memreserve declared
(besides T30) is Seaboard.

I'll remove it, as well as the extra model = line in the .dtsi.

Tom
>
> Regards,
> Simon