[RESEND 3/3] ram: rk3399: Conduct memory training at 400MHz

[Simon Glass]

On Thu, 11 Aug 2022 at 05:09, Lee Jones <lee at kernel.org> wrote:
>
> Currently the default initialisation frequency is 50MHz.  Although
> this does appear to be suitable for some LPDDR4 RAM chips, training at
> this low frequency has been seen to cause Column errors, leading to
> Capacity check errors on others.
>
> Here we force RAM initialisation to happen at 400MHz before ramping up
> to the final value running value of 800MHz after everything has been
> successfully configured.
>
> Link: https://lore.kernel.org/u-boot/Yo4v3jUeHXTovjOH@google.com/
> Suggested-by: YouMin Chen <cym at rock-chips.com>
> Signed-off-by: Lee Jones <lee at kernel.org>
> Tested-by: Xavier Drudis Ferran <xdrudis at tinet.cat>
> Reviewed-by: Kever Yang <kever.yang at rock-chips.com>
> ---
>  drivers/ram/rockchip/sdram_rk3399.c | 36 +++++++++++++++++------------
>  1 file changed, 21 insertions(+), 15 deletions(-)
>

Reviewed-by: Simon Glass <sjg at chromium.org>