rk3399 single channel lpddr4 setup

[Jagan Teki]

On Tue, Apr 21, 2020 at 7:54 PM Jack Mitchell <ml at embed.me.uk> wrote:
>
> Has anyone worked with an rk3399 based board with a single channel RAM
> setup? I've looked at the current code and made some changes for only
> setting up a single channel which basically consists of altering the
> loops down to one channel, however u-boot is hanging while checking for
> a successful frequency change here:
>
> >        /* change freq */
> >        writel((((0x3 << 4) | (1 << 2) | 1) << 16) |
> >               (fn << 4) | (1 << 2) | 1, &dram->cic->cic_ctrl0);
> >        while (!(readl(&dram->cic->cic_status0) & (1 << 2)))
> >                ;
> >
>
> I believe this is due to waiting for both channels to switch frequency
> which will never happen as there is only a single channel setup.
>
> Has anyone worked with a similar setup, or have any further
> documentation as the TRM only has a fairly basic register listing.

I have tried single-channel with DDR3 which is present on NOE4, I
believe the existing code does handle single channel for LPDDR4, can
you enable debugs and check on existing code. Usually the code cannot
go and try channel 1.

Jagan.