Make POST codes written to IO port optional

This adds more configurability to POST codes. The current assumption
is that POST codes should be written to an IO port (e.g. LPC) if POST
codes are enabled. This changes the assumption so that POST codes can
be written to the serial console without being written to an IO port.

This enables POST codes by default using "default y" to avoid
changing current behavior.

Change-Id: I3db91c358ccb1557096983c4d07f70b2e872c4b3
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/1685
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/console/Kconfig

@@ -360,9 +360,6 @@ config NO_POST
 	bool "Don't show any POST codes"
 	default n
 
-config POST_PORT
-	hex
-	default 0x80
 
 config CONSOLE_POST
 	bool "Show POST codes on the debug console"
@@ -391,5 +388,20 @@ config CMOS_POST_OFFSET
 	  If CONFIG_HAVE_OPTION_TABLE is enabled then it will use the value
 	  defined in the mainboard option table.
 
-endmenu
+config IO_POST
+	bool "Send POST codes to an IO port"
+	default y
+	help
+	  If enabled, POST codes will be written to an IO port.
 
+config IO_POST_PORT
+	depends on IO_POST
+	hex "IO port for POST codes"
+	default 0x80
+	help
+	  POST codes on x86 are typically written to the LPC bus on port
+	  0x80. However, it may be desireable to change the port number
+	  depending on the presence of coprocessors/microcontrollers or if the
+	  platform does not support IO in the conventional x86 manner.
+
+endmenu

src/console/post.c

@@ -100,7 +100,9 @@ void post_code(uint8_t value)
 #if CONFIG_CMOS_POST
 	cmos_post_code(value);
 #endif
-	outb(value, CONFIG_POST_PORT);
+#if CONFIG_IO_POST
+	outb(value, CONFIG_IO_POST_PORT);
+#endif
 #endif
 	mainboard_post(value);
 }