serial: sh-sci: Reorder the SCxTDR write after the TDxE clear.
authorPaul Mundt <lethal@linux-sh.org>
Thu, 13 Nov 2008 08:46:06 +0000 (17:46 +0900)
committerPaul Mundt <lethal@linux-sh.org>
Thu, 13 Nov 2008 08:46:06 +0000 (17:46 +0900)
commit272966c070237c8cb540fe67e06df51bc6ea9cc2
tree2937aa90cd6c972b13f0173f60e76c186111ffaf
parent5d52013cbb3d39bde9f5a6023193058eeb112e98
serial: sh-sci: Reorder the SCxTDR write after the TDxE clear.

Under qemu there is a race between the TDxE read-and-clear and the SCxTDR
write. While on hardware it can be gauranteed that the read-and-clear
will happen prior to the character being written out, no such assumption
can be made under emulation. As this path happens with IRQs off and the
hardware itself doesn't care about the ordering, move the SCxTDR write
until after the read-and-clear.

Signed-off-by: Vladimir Prus <vladimir@codesourcery.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
arch/sh/kernel/early_printk.c
drivers/serial/sh-sci.c