10.0-release proposed patch for Atmel

[Stanislav Sedov]

On Dec 21, 2013, at 10:44 PM, Warner Losh <imp at bsdimp.com> wrote:

> Gentlemen,
> 
> Right now, the mountroot prompt doesn't work on Atmel CPUs. Almost all the characters are eaten. I recently committed an elegant fix for this into head to mask the interrupt for new characters and only do polling.
> 
> However, it touched the base uart. In an abundance of caution, the re@ has asked me to see if I can come up with a fix w/o that.
> 
> A less elegant, less functional fix can be found at http://people.freebsd.org/~imp/at91-mountroot-10.diff
> 
> This fix defers turning on the RXRDY bit in the interrupt mask until we get the first interrupt after the first opening of the device. This is sufficient for mountroot> to work, but wouldn't fix things like GELI that prompt the user from the kernel. I think that's acceptable for 10.0 given the typical use case for atmel.
> 
> Can the folks here that know Atmel take a look at the patch and let me know what you think?
> 

Looks correct to me.  This is probably the safest way to go and will solve the issue
for the majority of use cases as you said.

Thanks!

--
ST4096-RIPE