2007-11-21 Till Straumann <strauman@slac.stanford.edu>

	* shared/console/uart.c: when draining UART during
	initialization (wait for possible printk() activity
	to finish) look at TEMT (fifo, holding-reg and shift-reg)
	rather than THRE (fifo, holding-reg only). This resolved
	some scrambled output issues for me.

	Enhanced semantics: if BSP initializes BSPBaseBaud to a negative
	value then the driver interprets the modulus as a speed value
	and uses the current setting of the divisor to compute the
	clock speed (BSPBaseBaud). This is useful if you have a board
	that you know is initialized e.g., to 9600 but you
	don't know the clock speed.

1 files changed, 7 insertions, 1 deletions

diff --git a/c/src/lib/libbsp/powerpc/shared/console/uart.c b/c/src/lib/libbsp/powerpc/shared/console/uart.c
index 11d9b64ce7..2e564a6af9 100644
--- a/c/src/lib/libbsp/powerpc/shared/console/uart.c
+++ b/c/src/lib/libbsp/powerpc/shared/console/uart.c
@@ -144,7 +144,7 @@ BSP_uart_init(int uart, int baud, int hwFlow)
   /* Make sure any printk activity drains before
    * re-initializing.
    */
-  while ( ! (uread(uart, LSR) & THRE) )
+  while ( ! (uread(uart, LSR) & TEMT) )
 	;
 
   switch(baud)
@@ -171,6 +171,12 @@ BSP_uart_init(int uart, int baud, int hwFlow)
   /* Set DLAB bit to 1 */
   uwrite(uart, LCR, DLAB);
 
+  if ( (int)BSPBaseBaud <= 0 ) {
+  	/* Use current divisor assuming BSPBaseBaud gives us the current speed */
+	BSPBaseBaud  = BSPBaseBaud ? -BSPBaseBaud : 9600;
+	BSPBaseBaud *= ((uread(uart, DLM) << 8) | uread(uart, DLL));
+  }
+
   /* Set baud rate */
   uwrite(uart, DLL,  (BSPBaseBaud/baud) & 0xff);
   uwrite(uart, DLM,  ((BSPBaseBaud/baud) >> 8) & 0xff);