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

[Prabhakar Kushwaha]

Dear Bin,

> -----Original Message-----
> From: Bin Meng [mailto:bmeng.cn at gmail.com]
> Sent: Friday, June 29, 2018 9:09 AM
> To: Prabhakar Kushwaha <prabhakar.kushwaha at nxp.com>
> Cc: York Sun <york.sun at nxp.com>; Simon Glass <sjg at chromium.org>; u-
> boot at lists.denx.de
> Subject: Re: [U-Boot] Support of device-tree for PowerPC platform: Query
> 
> 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.
> 

Sure binman can help in creating/combining firmware for flash.

But we still require flash map change to accommodate dtb.  This is the reason I want to use reserved area which is very far from u-boot, env etc. 
I was thinking about any possible issue if u-boot and dtb are not together. 

--pk