[U-Boot] Support of device-tree for PowerPC platform: Query

[Bin Meng]

Hi Prabhakar,

On Fri, Jun 29, 2018 at 10:55 AM, Prabhakar Kushwaha
<prabhakar.kushwaha at nxp.com> wrote:
>
>> -----Original Message-----
>> From: York Sun
>> Sent: Thursday, June 28, 2018 9:07 PM
>> To: Prabhakar Kushwaha <prabhakar.kushwaha at nxp.com>; Simon Glass
>> <sjg at chromium.org>
>> Cc: u-boot at lists.denx.de; Poonam Aggrwal <poonam.aggrwal at nxp.com>;
>> Jagdish Gediya <jagdish.gediya at nxp.com>
>> Subject: Re: Support of device-tree for PowerPC platform: Query
>>
>> On 06/27/2018 11:30 PM, Prabhakar Kushwaha wrote:
>>
>> <snip>
>>
>> >> Thanks for the direction.
>> >>
>> >> We will be following approach "a" with updated flash map.
>> >> We will allocate 1MB for uboot in flash. Out which 64K for DTB and
>> >> 960KB for u-boot for future increase.
>> >>
>> >> We will also update location of env and fman ucode for NXP platforms.
>> >>
>> >
>> >
>> > Other thought,
>> >  use CONFIG_OF_SEPARATE but **don't** concatenate dtb with u-boot.
>> In
>> > this case user has to program u-boot and dtb separately at different
>> > location. It will also have minimal impact on PowerPC platforms
>> >
>> > Just wondering if this approach has any disadvantages in longer run.
>> > What if user forget to program dtb and restart system??
>> >
>>
>> If we cannot combine DT with U-Boot image, we may have to live with two
>> separated images. We may have to shift the ENV sectors to make DT right
>> above U-Boot for convenience. If U-Boot can boot up and show a message of
>> missing DT, it is acceptable to me.
>>
>
> Putting DT in place of Env require lots of modification.
> I want to use existing QorIQ platform's memory map.
>
> Here 1 MB flash memory is reserved for Linux DTB.  Just wanted to split into 2 parts (Linux, uboot) with both size 512KB.
> This 1 MB location is far from u-boot, env, fman ucode.
>

Since the QorIQ parts have lots of firmware that need to be put in
flash, binman is the best choice here and can handle dtb as well.

Regards,
Bin