From: Scott Wood <scottwood@freescale.com>
Date: Tue, 18 Sep 2012 23:19:05 +0000 (-0500)
Subject: serial/ns16550: wait for TEMT before initializing
X-Git-Tag: v2013.01-rc2~117^2~27
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=cb55b3320014b7f6014416c556fe506efbf0a84b;p=kernel%2Fu-boot.git

serial/ns16550: wait for TEMT before initializing

TEMT is set when the transmitter is totally empty and all output has
finished.

This prevents output problems (including a loss of synchronization
observed on p2020 that persisted for quite a while) if SPL has output
still on its way out.

Signed-off-by: Scott Wood <scottwood@freescale.com>
--
v2: fixed typo in subject, and explained what the bit does in the changelog
---

diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 9027781..bbd91ca 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -36,6 +36,9 @@
 
 void NS16550_init(NS16550_t com_port, int baud_divisor)
 {
+	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
+		;
+
 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
 #if (defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)) || \
 					defined(CONFIG_AM33XX)