commit 34e21eeb2c41322cd58aab91c1485924975d4784
author John Rigby <john.rigby@linaro.org> Tue Apr 19 10:42:39 2011 +0000
committer Wolfgang Denk <wd@denx.de> Thu May 12 19:09:07 2011 +0200
tree 9ef4f320297799db6bf99aa0ea5d29d2bcf492fb
parent 2f968d85be0de020b6ed23a6b82f8fcd1bff55e8

Serial: p1011: new vendor init options

Two new options:

CONFIG_PL011_SERIAL_RLCR

Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
have separate receive and transmit line control registers.  Set
this variable to initialize the extra register.

CONFIG_PL011_SERIAL_FLUSH_ON_INIT

On some platforms (e.g. U8500) U-Boot is loaded by a second stage
boot loader that has already initialized the UART.  Define this
variable to flush the UART at init time.
empty fifo on init

Signed-off-by: John Rigby <john.rigby@linaro.org>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>

drivers/serial/serial_pl01x.c

diff --git a/drivers/serial/serial_pl01x.c b/drivers/serial/serial_pl01x.c
index 5dfcde8..7a064ff 100644
--- a/drivers/serial/serial_pl01x.c
+++ b/drivers/serial/serial_pl01x.c
@@ -111,6 +111,15 @@
 	unsigned int divider;
 	unsigned int remainder;
 	unsigned int fraction;
+	unsigned int lcr;
+
+#ifdef CONFIG_PL011_SERIAL_FLUSH_ON_INIT
+	/* Empty RX fifo if necessary */
+	if (readl(&regs->pl011_cr) & UART_PL011_CR_UARTEN) {
+		while (!(readl(&regs->fr) & UART_PL01x_FR_RXFE))
+			readl(&regs->dr);
+	}
+#endif
 
 	/* First, disable everything */
 	writel(0, &regs->pl011_cr);
@@ -131,9 +140,24 @@
 	writel(fraction, &regs->pl011_fbrd);
 
 	/* Set the UART to be 8 bits, 1 stop bit, no parity, fifo enabled */
-	writel(UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN,
-	       &regs->pl011_lcrh);
+	lcr = UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN;
+	writel(lcr, &regs->pl011_lcrh);
+
+#ifdef CONFIG_PL011_SERIAL_RLCR
+	{
+		int i;
+
+		/*
+		 * Program receive line control register after waiting
+		 * 10 bus cycles.  Delay be writing to readonly register
+		 * 10 times
+		 */
+		for (i = 0; i < 10; i++)
+			writel(lcr, &regs->fr);
 
+		writel(lcr, &regs->pl011_rlcr);
+	}
+#endif
 	/* Finally, enable the UART */
 	writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE | UART_PL011_CR_RXE,
 	       &regs->pl011_cr);