[U-Boot] [PATCH 02/14] sunxi: dram: Remove broken super-standby remnants

[Ian Campbell]

On Fri, 2014-07-18 at 19:22 +0300, Siarhei Siamashka wrote:
> If the dram->ppwrsctl (SDR_DPCR) register has the lowest bit set to 1, this
> means that DRAM is currently in self-refresh mode and retaining the old
> data. Since we have no idea what to do in this situation yet, just set this
> register to 0 and initialize DRAM in the same way as on any normal reboot
> (discarding whatever was stored there).
> 
> This part of code was apparently used by the Allwinner boot0 bootloader to
> handle resume from the so-called super-standby mode. But this particular
> code got somehow mangled on the way from the boot0 bootloader to the
> u-boot-sunxi bootloader and has no chance of doing anything even remotely
> sane. For example:
> 1. in the original boot0 code we had "mctl_write_w(SDR_DPCR, 0x16510000)"
>    (write to the register) and in the u-boot it now looks like
>    "setbits_le32(&dram->ppwrsctl, 0x16510000)" (set bits in the register)
> 2. in the original boot0 code it was issuing three commands "0x12, 0x17, 0x13"
>    (Self-Refresh entry, Self-Refresh exit, Refresh), but in the u-boot they
>    have become "0x12, 0x12, 0x13" (Self-Refresh entry, Self-Refresh entry,
>    Refresh)
> 
> Signed-off-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>

Acked-by: Ian Campbell <ijc at hellion.org.uk>