From 8ceeb4709845e38560a68b6c1b30cd607282abc0 Mon Sep 17 00:00:00 2001 From: Long Cheng Date: Thu, 25 Apr 2019 16:41:30 +0800 Subject: [PATCH] serial: 8250-mtk: add follow control Add SW and HW follow control function. Signed-off-by: Long Cheng Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_mtk.c | 60 +++++++++++++++++++++++--------------- 1 file changed, 37 insertions(+), 23 deletions(-) diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c index c1fdbc0..959fd85 100644 --- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -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 */ -- 2.7.4