[U-Boot] How do ARM platform initialize DDR?

[York Sun]

Albert,

Pardon me if this is a dumb question. I have been working on powerpc
platforms in the past. Now we (the developers I work with) are exploring
ARM cores. I am searching how memory is initialized and found different
solutions. Some platforms have memory ready before u-boot even starts,
some simply write to a set of registers. I understand many platforms
don't share the IP of DDR controller. I am wondering if there is generic
DDR driver used by many ARM platforms, like the one we have for
powerpc/mpc85xx SoCs.

Regards,

York