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Subject[PATCH 2/2] serial: 8250-mtk: modify baudrate setting
Date
In termios function, add Fractional divider to adjust baudrate.

Signed-off-by: Long Cheng <long.cheng@mediatek.com>
---
drivers/tty/serial/8250/8250_mtk.c | 102 ++++++++++++++++++++++++++++++++++++
1 file changed, 102 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 959fd85..417c7c8 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -25,13 +25,28 @@
#define MTK_UART_SAMPLE_COUNT 0x0a /* Sample count register */
#define MTK_UART_SAMPLE_POINT 0x0b /* Sample point register */
#define MTK_UART_RATE_FIX 0x0d /* UART Rate Fix Register */
+#define MTK_UART_ESCAPE_DAT 0x10 /* Escape Character register */
+#define MTK_UART_ESCAPE_EN 0x11 /* Escape Enable register */
#define MTK_UART_DMA_EN 0x13 /* DMA Enable register */
#define MTK_UART_RXTRI_AD 0x14 /* RX Trigger address */
#define MTK_UART_FRACDIV_L 0x15 /* Fractional divider LSB address */
#define MTK_UART_FRACDIV_M 0x16 /* Fractional divider MSB address */
+#define MTK_UART_IER_XOFFI 0x20 /* Enable XOFF character interrupt */
+#define MTK_UART_IER_RTSI 0x40 /* Enable RTS Modem status interrupt */
+#define MTK_UART_IER_CTSI 0x80 /* Enable CTS Modem status interrupt */
+
+#define MTK_UART_EFR_EN 0x10 /* Enable enhancement feature */
+#define MTK_UART_EFR_RTS 0x40 /* Enable hardware rx flow control */
+#define MTK_UART_EFR_CTS 0x80 /* Enable hardware tx flow control */
+#define MTK_UART_EFR_NO_SW_FC 0x0 /* no sw flow control */
+#define MTK_UART_EFR_XON1_XOFF1 0xa /* XON1/XOFF1 as sw flow control */
+#define MTK_UART_EFR_XON2_XOFF2 0x5 /* XON2/XOFF2 as sw flow control */
+#define MTK_UART_EFR_SW_FC_MASK 0xf /* Enable CTS Modem status interrupt */
+#define MTK_UART_EFR_HW_FC (MTK_UART_EFR_RTS | MTK_UART_EFR_CTS)
#define MTK_UART_DMA_EN_TX 0x2
#define MTK_UART_DMA_EN_RX 0x5

+#define MTK_UART_ESCAPE_CHAR 0x77 /* Escape char added under sw fc */
#define MTK_UART_TX_SIZE UART_XMIT_SIZE
#define MTK_UART_RX_SIZE 0x8000
#define MTK_UART_TX_TRIGGER 1
@@ -57,6 +72,13 @@ struct mtk8250_data {
#endif
};

+/* flow control mode */
+enum {
+ MTK_UART_FC_NONE,
+ MTK_UART_FC_SW,
+ MTK_UART_FC_HW,
+};
+
#ifdef CONFIG_SERIAL_8250_DMA
static void mtk8250_rx_dma(struct uart_8250_port *up);

@@ -195,6 +217,75 @@ static void mtk8250_shutdown(struct uart_port *port)
return serial8250_do_shutdown(port);
}

+static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask)
+{
+ serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask));
+}
+
+static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask)
+{
+ serial_out(up, UART_IER, serial_in(up, UART_IER) | mask);
+}
+
+static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
+{
+ struct uart_port *port = &up->port;
+ int lcr = serial_in(up, UART_LCR);
+
+ serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+ serial_out(up, UART_EFR, UART_EFR_ECB);
+ serial_out(up, UART_LCR, lcr);
+ lcr = serial_in(up, UART_LCR);
+
+ switch (mode) {
+ case MTK_UART_FC_NONE:
+ serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
+ serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
+ serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+ serial_out(up, UART_EFR, serial_in(up, UART_EFR) &
+ (~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK)));
+ serial_out(up, UART_LCR, lcr);
+ mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI |
+ MTK_UART_IER_RTSI | MTK_UART_IER_CTSI);
+ break;
+
+ case MTK_UART_FC_HW:
+ serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
+ serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
+ serial_out(up, UART_MCR, UART_MCR_RTS);
+ serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
+ /*enable hw flow control*/
+ serial_out(up, UART_EFR, MTK_UART_EFR_HW_FC |
+ (serial_in(up, UART_EFR) &
+ (~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
+
+ serial_out(up, UART_LCR, lcr);
+ mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI);
+ mtk8250_enable_intrs(up, MTK_UART_IER_CTSI | MTK_UART_IER_RTSI);
+ break;
+
+ case MTK_UART_FC_SW: /*MTK software flow control */
+ serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
+ serial_out(up, MTK_UART_ESCAPE_EN, 0x01);
+ serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
+ /*enable sw flow control */
+ serial_out(up, UART_EFR, MTK_UART_EFR_XON1_XOFF1 |
+ (serial_in(up, UART_EFR) &
+ (~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
+
+ serial_out(up, UART_XON1, START_CHAR(port->state->port.tty));
+ serial_out(up, UART_XOFF1, STOP_CHAR(port->state->port.tty));
+ serial_out(up, UART_LCR, lcr);
+ mtk8250_disable_intrs(up, MTK_UART_IER_CTSI|MTK_UART_IER_RTSI);
+ mtk8250_enable_intrs(up, MTK_UART_IER_XOFFI);
+ break;
+ default:
+ break;
+ }
+}
+
static void
mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
@@ -208,6 +299,7 @@ static void mtk8250_shutdown(struct uart_port *port)
struct uart_8250_port *up = up_to_u8250p(port);
unsigned int baud, quot, fraction;
unsigned long flags;
+ int mode;

#ifdef CONFIG_SERIAL_8250_DMA
if (up->dma) {
@@ -281,6 +373,16 @@ static void mtk8250_shutdown(struct uart_port *port)
serial_port_out(port, MTK_UART_FRACDIV_L, 0x00);
serial_port_out(port, MTK_UART_FRACDIV_M, 0x00);
}
+
+ if ((termios->c_cflag & CRTSCTS) && (!(termios->c_iflag & CRTSCTS)))
+ mode = MTK_UART_FC_HW;
+ else if (termios->c_iflag & CRTSCTS)
+ mode = MTK_UART_FC_SW;
+ else
+ mode = MTK_UART_FC_NONE;
+
+ mtk8250_set_flow_ctrl(up, mode);
+
if (uart_console(port))
up->port.cons->cflag = termios->c_cflag;

--
1.7.9.5
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