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Commit 8ceeb470 authored by Long Cheng's avatar Long Cheng Committed by Greg Kroah-Hartman
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serial: 8250-mtk: add follow control 



Add SW and HW follow control function.

Signed-off-by: default avatarLong Cheng <long.cheng@mediatek.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f1374017

drivers/tty/serial/8250/8250_mtk.c

+37 −23
Original line number Diff line number Diff line
@@ -21,12 +21,14 @@ 


#include "8250.h"



#define UART_MTK_HIGHS		0x09	/* Highspeed register */

#define UART_MTK_SAMPLE_COUNT	0x0a	/* Sample count register */

#define UART_MTK_SAMPLE_POINT	0x0b	/* Sample point register */

#define MTK_UART_HIGHS		0x09	/* Highspeed register */

#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_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_DMA_EN_TX	0x2

#define MTK_UART_DMA_EN_RX	0x5
@@ -46,6 +48,7 @@ enum dma_rx_status { 
struct mtk8250_data {

	int			line;

	unsigned int		rx_pos;

	unsigned int		clk_count;

	struct clk		*uart_clk;

	struct clk		*bus_clk;

	struct uart_8250_dma	*dma;
@@ -196,9 +199,15 @@ static void 
mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,

			struct ktermios *old)

{

	unsigned short fraction_L_mapping[] = {

		0, 1, 0x5, 0x15, 0x55, 0x57, 0x57, 0x77, 0x7F, 0xFF, 0xFF

	};

	unsigned short fraction_M_mapping[] = {

		0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 3

	};

	struct uart_8250_port *up = up_to_u8250p(port);

	unsigned int baud, quot, fraction;

	unsigned long flags;

	unsigned int baud, quot;



#ifdef CONFIG_SERIAL_8250_DMA

	if (up->dma) {
@@ -214,7 +223,7 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, 
	serial8250_do_set_termios(port, termios, old);



	/*

	 * Mediatek UARTs use an extra highspeed register (UART_MTK_HIGHS)

	 * Mediatek UARTs use an extra highspeed register (MTK_UART_HIGHS)

	 *

	 * We need to recalcualte the quot register, as the claculation depends

	 * on the vaule in the highspeed register.
@@ -230,18 +239,11 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, 
				  port->uartclk / 16 / UART_DIV_MAX,

				  port->uartclk);



	if (baud <= 115200) {

		serial_port_out(port, UART_MTK_HIGHS, 0x0);

	if (baud < 115200) {

		serial_port_out(port, MTK_UART_HIGHS, 0x0);

		quot = uart_get_divisor(port, baud);

	} else if (baud <= 576000) {

		serial_port_out(port, UART_MTK_HIGHS, 0x2);



		/* Set to next lower baudrate supported */

		if ((baud == 500000) || (baud == 576000))

			baud = 460800;

		quot = DIV_ROUND_UP(port->uartclk, 4 * baud);

	} else {

		serial_port_out(port, UART_MTK_HIGHS, 0x3);

		serial_port_out(port, MTK_UART_HIGHS, 0x3);

		quot = DIV_ROUND_UP(port->uartclk, 256 * baud);

	}
@@ -258,17 +260,29 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, 
	/* reset DLAB */

	serial_port_out(port, UART_LCR, up->lcr);



	if (baud > 460800) {

	if (baud >= 115200) {

		unsigned int tmp;



		tmp = DIV_ROUND_CLOSEST(port->uartclk, quot * baud);

		serial_port_out(port, UART_MTK_SAMPLE_COUNT, tmp - 1);

		serial_port_out(port, UART_MTK_SAMPLE_POINT,

					(tmp - 2) >> 1);

		tmp = (port->uartclk / (baud *  quot)) - 1;

		serial_port_out(port, MTK_UART_SAMPLE_COUNT, tmp);

		serial_port_out(port, MTK_UART_SAMPLE_POINT,

					(tmp >> 1) - 1);



		/*count fraction to set fractoin register */

		fraction = ((port->uartclk  * 100) / baud / quot) % 100;

		fraction = DIV_ROUND_CLOSEST(fraction, 10);

		serial_port_out(port, MTK_UART_FRACDIV_L,

						fraction_L_mapping[fraction]);

		serial_port_out(port, MTK_UART_FRACDIV_M,

						fraction_M_mapping[fraction]);

	} else {

		serial_port_out(port, UART_MTK_SAMPLE_COUNT, 0x00);

		serial_port_out(port, UART_MTK_SAMPLE_POINT, 0xff);

		serial_port_out(port, MTK_UART_SAMPLE_COUNT, 0x00);

		serial_port_out(port, MTK_UART_SAMPLE_POINT, 0xff);

		serial_port_out(port, MTK_UART_FRACDIV_L, 0x00);

		serial_port_out(port, MTK_UART_FRACDIV_M, 0x00);

	}

	if (uart_console(port))

		up->port.cons->cflag = termios->c_cflag;



	spin_unlock_irqrestore(&port->lock, flags);

	/* Don't rewrite B0 */