From: Alexey Brodkin Date: Sat, 8 Feb 2014 06:10:01 +0000 (+0400) Subject: serial/serial_arc: add work-around of ISS bug X-Git-Tag: v2014.04-rc2~126 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=1d568c7666e81fa920de38a3c83895764ea8cf0f;p=oweals%2Fu-boot.git serial/serial_arc: add work-around of ISS bug Explanation is in in-lined comment. Signed-off-by: Alexey Brodkin Cc: Vineet Gupta Cc: Noam Camus Cc: Tom Rini --- diff --git a/drivers/serial/serial_arc.c b/drivers/serial/serial_arc.c index e63d25d794..55d07691fc 100644 --- a/drivers/serial/serial_arc.c +++ b/drivers/serial/serial_arc.c @@ -39,7 +39,23 @@ static void arc_serial_setbrg(void) arc_console_baud = gd->cpu_clk / (gd->baudrate * 4) - 1; writel(arc_console_baud & 0xff, ®s->baudl); + +#ifdef CONFIG_ARC + /* + * UART ISS(Instruction Set simulator) emulation has a subtle bug: + * A existing value of Baudh = 0 is used as a indication to startup + * it's internal state machine. + * Thus if baudh is set to 0, 2 times, it chokes. + * This happens with BAUD=115200 and the formaula above + * Until that is fixed, when running on ISS, we will set baudh to !0 + */ + if (gd->arch.running_on_hw) + writel((arc_console_baud & 0xff00) >> 8, ®s->baudh); + else + writel(1, ®s->baudh); +#else writel((arc_console_baud & 0xff00) >> 8, ®s->baudh); +#endif } static int arc_serial_init(void)