tree ae8bb037cb325b841b003320dda5b7d327fa5b26
parent 284d9010118d3c159ca963ef54704beadaed23ac
author Stefan Agner <stefan@agner.ch> 1408463667 +0200
committer Stefano Babic <sbabic@denx.de> 1410274364 +0200

arm: vf610: lpuart: fix status register handling

The status register 1 (S1) is not writeable, hence we should not
write it. In order to clear the RDRF flag we only need to read
the data register.

Also, when stressing U-Boot a lot with serial input, an overflow can
occur which asserts the S1_OR flag (while not asserting the S1_RDRF
flag). To clear this flag we again just need to read the data
register, hence add this flag to the abort conditions for the while
loop.

Insert a compiler barrier to make sure reading the data register
gets executed after reading the status register.

Signed-off-by: Stefan Agner <stefan@agner.ch>