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authorAlexey Brodkin <Alexey.Brodkin@synopsys.com>2014-02-08 10:10:01 +0400
committerTom Rini <trini@ti.com>2014-02-21 07:54:05 -0500
commit1d568c7666e81fa920de38a3c83895764ea8cf0f (patch)
treebd6cf473cb378c4355e65f9d579a0c2c0af4a4a5 /drivers
parent6853e6aa77b388998a5368b400aee3ae7776b1c2 (diff)
serial/serial_arc: add work-around of ISS bug
Explanation is in in-lined comment. Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Noam Camus <noamc@ezchip.com> Cc: Tom Rini <trini@ti.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/serial/serial_arc.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/serial/serial_arc.c b/drivers/serial/serial_arc.c
index e63d25d7949..55d07691fcf 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, &regs->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, &regs->baudh);
+ else
+ writel(1, &regs->baudh);
+#else
writel((arc_console_baud & 0xff00) >> 8, &regs->baudh);
+#endif
}
static int arc_serial_init(void)