lpc reset questions

[Joel Stanley]

Hello Eugene,

On 6 June 2018 at 01:58,  <Eugene.Cho at dell.com> wrote:
>    I was trying to follow the following submission  https://lkml.org/lkml/2018/2/19/12,
> so best I can tell is on Aspeed this "reset-simple driver" will just take the UART
> out-of-reset, because Aspeed automatically puts the UART in reset on LPC-reset????
> Did I get that right?

At power on, the aspeed ties the reset of UART1 and UART2 to the LPC
reset. I figure this is because they have a "SUART" mode, where host
SIO accesses are used to program the BMC's UART directly from the host
over the LPC.

This doesn't work for Linux on the BMC as it expects the device to be
functional when it loads it's driver. Hence, the simple-reset driver
pokes at the tied-to-LPC-reset bit, effectively taking the UART out of
reset.

Cheers,

Joel