From c706030ca2374fc3219010fcd479e0b5de36cabf Mon Sep 17 00:00:00 2001
From: pinkasfeld joseph <jpinkasfeld@xxxxxxxxxxxxxxxxxxxxxx>
Date: Wed, 18 Nov 2009 16:35:16 +0100
Subject: [PATCH 2/2] serial 16c950 : add preliminary support for 9-bit receive and transmit
2 bytes must be written or read for transmiting or receiving 9-bit data
first byte LSB is ninth bit, second byte is normal data
Signed-off-by: pinkasfeld joseph <jpinkasfeld@xxxxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/8250.c | 54 ++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 49 insertions(+), 5 deletions(-)
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 737b4c9..1b4143f 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -134,6 +134,7 @@ struct uart_8250_port {
unsigned short bugs; /* port bugs */
unsigned int tx_loadsz; /* transmit fifo load size */
unsigned char acr;
+ unsigned char nmr;
unsigned char ier;
unsigned char lcr;
unsigned char mcr;
@@ -835,6 +836,7 @@ static void autoconfig_has_efr(struct uart_8250_port *up)
* recommended for new designs).
*/
up->acr = 0;
+ up->nmr = 0;
serial_out(up, UART_LCR, 0xBF);
serial_out(up, UART_EFR, UART_EFR_ECB);
serial_out(up, UART_LCR, 0x00);
@@ -1385,8 +1387,8 @@ static void
receive_chars(struct uart_8250_port *up, unsigned int *status)
{
struct tty_struct *tty = up->port.state->port.tty;
- unsigned char ch, lsr = *status;
- int max_count = 256;
+ unsigned char ch, ch9, lsr = *status;
+ int error_break = 0, max_count = 256;
char flag;
do {
@@ -1408,7 +1410,20 @@ receive_chars(struct uart_8250_port *up, unsigned int *status)
lsr |= up->lsr_saved_flags;
up->lsr_saved_flags = 0;
- if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
+ /*
+ * Due to sharing of bit 2 in LSR depending on 9 bits mode
+ * bit 2 rise Parity Error or 9th bit read
+ */
+ error_break = 0 ;
+ if (up->nmr & UART_NMR_9BENB) {
+ if (lsr & UART_LSR_NBM_BRK_ERROR_BITS)
+ error_break = 1;
+ } else {
+ if (lsr & UART_LSR_BRK_ERROR_BITS)
+ error_break = 1;
+ }
+
+ if (unlikely(error_break)) {
/*
* For statistics only
*/
@@ -1423,7 +1438,8 @@ receive_chars(struct uart_8250_port *up, unsigned int *status)
*/
if (uart_handle_break(&up->port))
goto ignore_char;
- } else if (lsr & UART_LSR_PE)
+ } else if ((lsr & UART_LSR_PE) &&
+ !(up->nmr & UART_NMR_9BENB))
up->port.icount.parity++;
else if (lsr & UART_LSR_FE)
up->port.icount.frame++;
@@ -1438,7 +1454,8 @@ receive_chars(struct uart_8250_port *up, unsigned int *status)
if (lsr & UART_LSR_BI) {
DEBUG_INTR("handling break....");
flag = TTY_BREAK;
- } else if (lsr & UART_LSR_PE)
+ } else if ((lsr & UART_LSR_PE) &&
+ !(up->nmr & UART_NMR_9BENB))
flag = TTY_PARITY;
else if (lsr & UART_LSR_FE)
flag = TTY_FRAME;
@@ -1446,6 +1463,16 @@ receive_chars(struct uart_8250_port *up, unsigned int *status)
if (uart_handle_sysrq_char(&up->port, ch))
goto ignore_char;
+ /*
+ * In 9bit mode Parity error is replace by 9th bit
+ */
+ if (up->nmr & UART_NMR_9BENB) {
+ if (lsr & UART_LSR_9TH_BIT)
+ ch9 = 1;
+ else
+ ch9 = 0;
+ uart_insert_char(&up->port, lsr, UART_LSR_OE, ch9, flag);
+ }
uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
ignore_char:
@@ -1479,6 +1506,13 @@ static void transmit_chars(struct uart_8250_port *up)
count = up->tx_loadsz;
do {
+ /* first byte contain 9th bit for 9 bit mode */
+ if ((up->nmr & UART_NMR_9BENB) && (count > 1) ){
+ serial_out(up, UART_SCR, 0x01 & xmit->buf[xmit->tail]);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ if (uart_circ_empty(xmit))
+ break;
+ }
serial_out(up, UART_TX, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
up->port.icount.tx++;
@@ -1956,6 +1990,7 @@ static int serial8250_startup(struct uart_port *port)
if (up->port.type == PORT_16C950) {
/* Wake up and initialize UART */
up->acr = 0;
+ up->nmr = 0;
serial_outp(up, UART_LCR, 0xBF);
serial_outp(up, UART_EFR, UART_EFR_ECB);
serial_outp(up, UART_IER, 0);
@@ -2412,6 +2447,15 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
/* Don't rewrite B0 */
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
+
+ /*
+ * 9-bit mode control flag on 16c950
+ */
+ if (termios->c_cflag & CNBENB) {
+ up->nmr |= UART_NMR_9BENB;
+ serial_icr_write(up, UART_NMR, up->nmr);
+ }
+
}
static void
--
1.6.5.2
