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

[Eugeniu Rosca]

Hi Marek cc: Michael

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?

2. I see more DRAM-related compile-time knobs in vanilla ATF:
➜  arm-trusted-firmware (c48d02bade88) $ grep "DRAM.*:"
plat/renesas/rcar/platform.mk
RCAR_DRAM_SPLIT := 0
RCAR_DRAM_LPDDR4_MEMCONF :=1
RCAR_DRAM_DDR3L_MEMCONF :=1
RCAR_DRAM_DDR3L_MEMDUAL :=1
RCAR_DRAM_CHANNEL :=15

My understanding is that these are local to ATF and U-Boot can stay
agnostic about them? IOW, DRAM start and size are totally enough for
U-Boot? TIA!

Best regards,
Eugeniu.