[U-Boot] [PATCH 4/4] ARM: renesas: Configure DRAM size from ATF DT fragment

[Eugeniu Rosca]

On Tue, Mar 12, 2019 at 10:11:21PM +0100, Marek Vasut wrote:
> On 3/12/19 8:30 PM, Eugeniu Rosca wrote:
> > Hi Marek cc: Michael
> 
> Hi,
> 
> > On Tue, Mar 5, 2019 at 4:37 AM Marek Vasut <marek.vasut at gmail.com> wrote:
> >>
> >> The ATF can pass additional information via the first four registers,
> >> x0...x3. The R-Car Gen3 with mainline ATF, register x1 contains pointer
> >> to a device tree with platform information. Parse this device tree and
> >> extract DRAM size information from it. This is useful on systems where
> >> the DRAM size can vary between configurations.
> > 
> > 1. Do the ATF changes supporting this feature already exist in mainline ATF?
> 
> Yes, for quite some time, see
> commit 1d85c4bd5b6291b99feb2409525c96f0c1744328
>     plat: rcar: Pass DTB with DRAM layout from BL2 to next stages

That's helpful, but I think such information should go by default into
commit description.

[..]

Besides the above, I wonder why this patch duplicates code across three
board files? Could this code be relocated to some common area like [1]?
FWIW building the latter could be re-enabled by reverting the Makefile
changes from v2018.01-rc1 commit [2].

To differentiate between the boards which expect/require the ATF args
and those which don't, I guess that run-time (IS_ENABLED) checking of
a newly created Kconfig symbol, e.g. SUPPORTS_ATF_ARGS or similar,
selected on per-board basis, could do the job?

Note that we already face the need to have an area for Android features
common between all Gen3 boards, so I think reviving [1] is inevitable.

[1] board/renesas/rcar-common/common.c
[2] http://git.denx.de/?p=u-boot.git;a=commitdiff;h=e23eb942ad10
    ("ARM: rmobile: Stop using rcar-common/common.c on Gen3")

Best regards,
Eugeniu.