The UART divider should be calculated based on the base frequency

and baudrate, not hardcoded in addition to that.

Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Acked-by: Peter Stuge <peter@stuge.se>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6538 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

diff --git a/src/console/uart8250_console.c b/src/console/uart8250_console.c
index 53ca3a762ef0d96d8ceefc75622c36d18ac1dbeb..03db400319f89c30ffd3f2bef4d90ebaceb23806 100644 (file)
--- a/src/console/uart8250_console.c
+++ b/src/console/uart8250_console.c
@@ -25,7 +25,13 @@ static void ttyS0_init(void)
 {
        static const unsigned char div[8] = { 1, 2, 3, 6, 12, 24, 48, 96 };
        int b_index = 0;
-       unsigned int divisor = CONFIG_TTYS0_DIV;
+       /* TODO the divisor calculation is hard coded to standard UARTs. Some
+        * UARTs won't work with these values. This should be a property of the
+        * UART used, worst case a Kconfig variable. For now live with hard
+        * codes as the only devices that might be different are the iWave
+        * iRainbowG6 and the OXPCIe952 card (and the latter is memory mapped)
+        */
+       unsigned int divisor = 115200 / CONFIG_TTYS0_BAUD;
 
        if (get_option(&b_index, "baud_rate") == 0) {
                divisor = div[b_index];

diff --git a/src/include/uart8250.h b/src/include/uart8250.h
index 3918bf1333f71502712e548c81f83cc89b9e6475..217558a8d50e1fc782d0c69d6f13ceeb9254b126 100644 (file)
--- a/src/include/uart8250.h
+++ b/src/include/uart8250.h
@@ -28,13 +28,9 @@
 #ifndef CONFIG_TTYS0_BAUD
 #define CONFIG_TTYS0_BAUD 115200
 #endif
-
-#ifndef CONFIG_TTYS0_DIV
 #if ((115200%CONFIG_TTYS0_BAUD) != 0)
 #error Bad ttys0 baud rate
 #endif
-#define CONFIG_TTYS0_DIV       (115200/CONFIG_TTYS0_BAUD)
-#endif
 
 /* Line Control Settings */
 #ifndef CONFIG_TTYS0_LCS

diff --git a/src/lib/uart8250.c b/src/lib/uart8250.c
index 03d954ba2c9dd02707ce54fcd6cf93d2e8ee43fe..e7a75017a95fa570b8150fff81a309000b93cbbc 100644 (file)
--- a/src/lib/uart8250.c
+++ b/src/lib/uart8250.c
@@ -88,6 +88,12 @@ void uart8250_init(unsigned base_port, unsigned divisor)
 #if defined(__PRE_RAM__) || defined(__SMM__)
 void uart_init(void)
 {
+       /* TODO the divisor calculation is hard coded to standard UARTs. Some
+        * UARTs won't work with these values. This should be a property of the
+        * UART used, worst case a Kconfig variable. For now live with hard
+        * codes as the only devices that might be different are the iWave
+        * iRainbowG6 and the OXPCIe952 card (and the latter is memory mapped)
+        */
 #if CONFIG_USE_OPTION_TABLE && !defined(__SMM__)
         static const unsigned char divisor[] = { 1, 2, 3, 6, 12, 24, 48, 96 };
         unsigned ttys0_div, ttys0_index;
@@ -97,7 +103,7 @@ void uart_init(void)
 
        uart8250_init(CONFIG_TTYS0_BASE, ttys0_div);
 #else
-       uart8250_init(CONFIG_TTYS0_BASE, CONFIG_TTYS0_DIV);
+       uart8250_init(CONFIG_TTYS0_BASE, (115200 / CONFIG_TTYS0_BAUD));
 #endif
 }
 #endif

diff --git a/src/mainboard/iwave/iWRainbowG6/Kconfig b/src/mainboard/iwave/iWRainbowG6/Kconfig
index 7005bd365e1cfef1179072abca3821e20f07c1f4..7ec8029579cca1fdb035034b761dcf11c69b98ba 100644 (file)
--- a/src/mainboard/iwave/iWRainbowG6/Kconfig
+++ b/src/mainboard/iwave/iWRainbowG6/Kconfig
@@ -37,9 +37,7 @@ config IRQ_SLOT_COUNT
        int
        default 10
 
-# WTF, is this 19200?
-config TTYS0_DIV
-       int
-       default 6
+# This mainboard might have a higher clocked UART or might not be able to run
+# serial output at 115200 baud
 
 endif