[coreboot-gerrit] Change in coreboot[master]: mb/intel/dg43gt: Fix very long boot delays with USE_OPTION_TABLE

[Arthur Heymans (Code Review)]

Arthur Heymans has uploaded this change for review. ( https://review.coreboot.org/21641


Change subject: mb/intel/dg43gt: Fix very long boot delays with USE_OPTION_TABLE
......................................................................

mb/intel/dg43gt: Fix very long boot delays with USE_OPTION_TABLE

With USE_OPTION_TABLE console_init() will fetch both baudrate and
debug level from rtc nvram. These functions will at some point try to
create some output even though console is not ready yet.

This board seems to have the COMA hardware in an undefined state with
a very low divisor which results in long boot delay ~30s.
Setting the BDLAB bit seems to fix it.

Change-Id: I6a23ef9577161084521b569fc3870a27f50624d1
Signed-off-by: Arthur Heymans <arthur at aheymans.xyz>
---
M src/mainboard/intel/dg43gt/romstage.c
1 file changed, 10 insertions(+), 0 deletions(-)



  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/41/21641/1

diff --git a/src/mainboard/intel/dg43gt/romstage.c b/src/mainboard/intel/dg43gt/romstage.c
index 6944b18..b84f5a2 100644
--- a/src/mainboard/intel/dg43gt/romstage.c
+++ b/src/mainboard/intel/dg43gt/romstage.c
@@ -26,6 +26,7 @@
 #include <lib.h>
 #include <northbridge/intel/x4x/iomap.h>
 #include <timestamp.h>
+#include <drivers/uart/uart8250reg.h>
 
 #define SERIAL_DEV PNP_DEV(0x2e, W83627DHG_SP1)
 #define LPC_DEV PCI_DEV(0, 0x1f, 0)
@@ -83,6 +84,15 @@
 	mb_gpio_init();
 	winbond_enable_serial(SERIAL_DEV, CONFIG_TTYS0_BASE);
 
+	/* Aparantly the COMA port is booted in an undefined state in which
+	 * the divisor is very high. In console_init() some functions are
+	 * called which print to the console resulting in very long
+	 * (up to 30s) boot delays.
+	 * Setting the Baudrate Divisor Latch Access Bit (BDLAB) here fixes it.
+	 */
+	if (CONFIG_TTYS0_BASE == 0x3f8)
+		outb(UART8250_LCR_DLAB, CONFIG_TTYS0_BASE + UART8250_LCR);
+
 	console_init();
 
 	report_bist_failure(bist);

-- 
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Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I6a23ef9577161084521b569fc3870a27f50624d1
Gerrit-Change-Number: 21641
Gerrit-PatchSet: 1
Gerrit-Owner: Arthur Heymans <arthur at aheymans.xyz>
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