Fix au1x00_serial baud rate calculation:

remove hardcoded cpu clock divisor and use register instead;
round up instead of truncate
Patch by Andrew Dyer, 15 Feb 2005

CHANGELOG

@@ -2,8 +2,13 @@
 Changes for U-Boot 1.1.4:
 ======================================================================
 
+* Fix au1x00_serial baud rate calculation:
+  remove hardcoded cpu clock divisor and use register instead;
+  round up instead of truncate
+  Patch by Andrew Dyer, 15 Feb 2005
+
 * Add Xilinx Spartan3 family FPGA support
-  Patch by Kurt Stremerch, 14 February 2005
+  Patch by Kurt Stremerch, 14 Feb 2005
 
 * Fix drivers/cfi_flash.c: use info->reset_cmd instead of FLASH_CMD_RESET
   Patch by Zachary Landau, 11 Feb 2005

cpu/mips/au1x00_serial.c

@@ -70,9 +70,21 @@ void serial_setbrg (void)
 {
 	volatile u32 *uart_clk = (volatile u32*)(UART0_ADDR+UART_CLK);
 	volatile u32 *uart_lcr = (volatile u32*)(UART0_ADDR+UART_LCR);
+	volatile u32 *sys_powerctrl = (u32 *)SYS_POWERCTRL;
+	int sd;
+	int divisorx2;
 
-	/* Set baudrate - FIXME for bus speeds != CPU/2 */
-	*uart_clk = ((CFG_HZ/(CONFIG_BAUDRATE * 64)));
+	/* sd is system clock divisor			*/
+	/* see section 10.4.5 in au1550 datasheet	*/
+	sd = (*sys_powerctrl & 0x03) + 2;
+
+	/* calulate 2x baudrate and round */
+	divisorx2 = ((CFG_HZ/(sd * 16 * CONFIG_BAUDRATE)));
+
+	if (divisorx2 & 0x01)
+		divisorx2 = divisorx2 + 1;
+
+	*uart_clk = divisorx2 / 2;
 
 	/* Set parity, stop bits and word length to 8N1 */
 	*uart_lcr = UART_LCR_WLEN8;