[U-Boot] [PATCHv3 1/4] Serial: p1011: new vendor init options
John Rigby
john.rigby at linaro.org
Tue Apr 12 08:17:44 CEST 2011
From: Rabin Vincent <rabin.vincent at stericsson.com>
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: Rabin Vincent <rabin.vincent at stericsson.com>
Signed-off-by: John Rigby <john.rigby at linaro.org>
---
v3:
Enable changes with new CONFIG_* options instead of platform.
Document new CONFIG_* options in README.
README | 12 ++++++++++++
drivers/serial/serial_pl01x.c | 17 +++++++++++++++--
drivers/serial/serial_pl01x.h | 4 ++++
3 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/README b/README
index c128a6c..8ccac6e 100644
--- a/README
+++ b/README
@@ -468,6 +468,18 @@ The following options need to be configured:
define this to a list of base addresses for each (supported)
port. See e.g. include/configs/versatile.h
+ 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.
+
- Console Interface:
Depending on board, define exactly one serial port
diff --git a/drivers/serial/serial_pl01x.c b/drivers/serial/serial_pl01x.c
index 5dfcde8..164b0ac 100644
--- a/drivers/serial/serial_pl01x.c
+++ b/drivers/serial/serial_pl01x.c
@@ -111,6 +111,15 @@ int serial_init (void)
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(®s->pl011_cr) & UART_PL011_CR_UARTEN) {
+ while (!(readl(®s->fr) & UART_PL01x_FR_RXFE))
+ readl(®s->dr);
+ }
+#endif
/* First, disable everything */
writel(0, ®s->pl011_cr);
@@ -131,9 +140,13 @@ int serial_init (void)
writel(fraction, ®s->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,
- ®s->pl011_lcrh);
+ lcr = UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN;
+ writel(lcr, ®s->pl011_lcrh);
+#ifdef CONFIG_PL011_SERIAL_RLCR
+ /* program receive line control register */
+ writel(lcr, ®s->pl011_rlcr);
+#endif
/* Finally, enable the UART */
writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE | UART_PL011_CR_RXE,
®s->pl011_cr);
diff --git a/drivers/serial/serial_pl01x.h b/drivers/serial/serial_pl01x.h
index b670c24..96ee381 100644
--- a/drivers/serial/serial_pl01x.h
+++ b/drivers/serial/serial_pl01x.h
@@ -43,7 +43,11 @@ struct pl01x_regs {
u32 pl010_lcrl; /* 0x10 Line control register, low byte */
u32 pl010_cr; /* 0x14 Control register */
u32 fr; /* 0x18 Flag register (Read only) */
+#ifdef CONFIG_PL011_SERIAL_RLCR
+ u32 pl011_rlcr; /* 0x1c Receive line control register */
+#else
u32 reserved;
+#endif
u32 ilpr; /* 0x20 IrDA low-power counter register */
u32 pl011_ibrd; /* 0x24 Integer baud rate register */
u32 pl011_fbrd; /* 0x28 Fractional baud rate register */
--
1.7.1
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