w83627hf fast serial port driver available

[Tony Lindgren]

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Hi all,

I just posted a driver that enables the high speed serial port modes
for the w83627 chip used on many motherboards, such as Tyan S2460.

To use the driver, you also need to use setserial after loading the
driver to enable the high speed mode.

Hopefully somebody someday will combine all the high speed serial
port drivers into some generic high speed serial port driver...

You can also download the driver from:

https://www.muru.com/linux/w83627hf/

Tony

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/*
 * Winbond W83627HF fast serial port driver for Linux 2.4.x
 *
 * Copyright (C) 2002 Tony Lindgren <[e-mail]>
 *
 * NOTE: In order to use this module, load the module and then set the 
 * serial port with a custom divisor. For example, to use speed 230400, 
 * use command:
 *
 * setserial /dev/ttyS0 uart 16550A baud_base 921600 spd_cust divisor 4
 *
 * If you remove the module, and want to reset the serial port, use:
 *
 * setserial /dev/ttyS0 uart 16550A baud_base 115200 spd_normal divisor 1
 *
 * The chip init code is copied from the w83627hf-wdt.c watchdog driver, 
 * Copyright (C) 2000 Matthias Cramer <[e-mail]>.
 *
 * This software is licensed under GNU General Public License Version 2 
 * as specified in file COPYING in the Linux kernel source tree main 
 * directory.

 Compile comand:
   gcc -D__KERNEL__ -I/usr/src/linux/include -Wall -Wstrict-prototypes -O2 \
   -DMODULE -DMODVERSIONS -include /usr/src/linux/include/linux/modversions.h \
   -c w83627hf-fast-serial.c

*/

#include <linux/config.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>

//#define DEBUG 1

#define WDT_UART0		(0x00)
#define WDT_UART1		(0x01)

/* UART normal mode */
#define WDT_RBR			(0x00)	/* Receiver buffer register */
#define WDT_TBR			(0x00)	/* Transmit buffer register */
#define WDT_ICR			(0x01)	/* Interrupt control register */
#define WDT_UCR			(0x03)	/* UART control register */
#define WDT_UDR			(0x07)	/* User defined register */

/* UART BDLAB mode */
#define WDT_BLL			(0x00)	/* Baudrate divisor latch low */
#define WDT_BLH			(0x01)	/* Baudrate divisor latch high */

/* W83627 control registers */
#define WDT_CR30			/* UART A, logical device 2 */
#define WDT_CR

#define WDT_CRF0		(0x00)	/* WD config register 0 */

#define WDT_CLOCK_1846200	(0x00)	/* 1.8462MHz clock source (24MHz/13) */	
#define WDT_CLOCK_2000000	(0x01)	/* 2MHz clock source (24MHz/12) */
#define WDT_CLOCK_2400000	(0x02)	/* 24MHz clock source (24MHz/1) */
#define WDT_CLOCK_1476000	(0x03)	/* 14.769MHz clock src (24MHz/1.625) */

#define WDT_EFER		(io+0)	/* Extended Function Enable Registers */
#define WDT_EFIR		(io+0)	/* Ext Funct Index Reg (same as EFER) */
#define WDT_EFDR		(WDT_EFIR+1)	/* Extended Func Data Register */

static void w83627_enter_ext_mode(void);
static void w83627_leave_ext_mode(void);

/*
 *	You must set these - there is no sane way to probe for this board.
 *	You can use w83627=x to set these now.
 */
 
static int io=0x2E;			/* Portwell Boards, S2460 */
//static int io=0x4e;			/* Maybe used on some other boards */

#ifndef MODULE

/**
 *	w83627_setup:
 *	@str: command line string
 *
 *	Setup options. The board isn't really probe-able so we have to
 *	get the user to tell us the configuration. Sane people build it 
 *	modular but the others come here.
 */
 
static int __init w83627_setup(char *str)
{
	int ints[4];

	str = get_options (str, ARRAY_SIZE(ints), ints);

	if (ints[0] > 0)
	{
		io = ints[1];
	}

	return 1;
}

__setup("w83627=", w83627_setup);

#endif /* !MODULE */

static void w83627_enter_ext_mode()
{
 	outb_p(0x87, WDT_EFER);		/* Enter extended function mode */
 	outb_p(0x87, WDT_EFER);		/* Do it twice !! */
 	
}

static void w83627_leave_ext_mode(void)
{
 	outb_p(0x0AA, WDT_EFER);	/* Leave extended function mode */
}

/*
 * Sets the UART into baud rate change mode
 */
static void w83627_enter_bdlab_mode(int port)
{
	int ucr = 0;

	printk(KERN_INFO "Entering bdlab mode to change the UART speed\n");
	ucr = inb_p(port + WDT_UCR);
	ucr |= (1 << 7);		/* Set baud divisor latch access bit */
	outb_p(ucr, port + WDT_UCR);
}

/*
 * Returns the serial port to the normal mode
 */
static void w83627_leave_bdlab_mode(int port)
{
	int ucr = 0;

	printk(KERN_INFO "Leaving bdlab mode\n");
	ucr = inb_p(port + WDT_UCR);
	ucr &= ~(1 << 7);		/* Clear baud divisor latch access bit */
	outb_p(ucr, port + WDT_UCR);
}

/*
 * Returns the logical device number based on the UART number
 */
static int w83627_get_uart_logical_device(int uartno)
{
	int l_dev;

	switch (uartno) {
	case 0:
		l_dev = 0x02;
		break;
	case 1:
		l_dev = 0x03;
		break;
	default:
		printk(KERN_INFO "Unknown logical device for UART\n");
		return 0;
	}
	return l_dev;
}

/*
 * Gets the UART baud rate divisor
 */
static int w83627_get_baud_divisor(int port)
{
	int bdr = 0;

	bdr = inb_p(port + WDT_BLL);	/* Baudrate divisor low register */
	printk(KERN_INFO "Baudrate divisor low register: 0x%x\n", bdr);
	bdr = (bdr << 8);
	bdr |= inb_p(port + WDT_BLH);	/* Baudrate divisor high register */
	printk(KERN_INFO "Baudrate divisor: 0x%x\n", bdr);

	return bdr;
}

/*
 * Sets the UART baud rate divisor
 */
static void w83627_set_baud_divisor(int div, int port)
{
	outb_p(div & 0xff, port + WDT_BLH);
	outb_p(div >> 8, port + WDT_BLL);
}

/*
 * Gets the selected UART port address
 */
static int w83627_get_uart_port(int uartno)
{
	int l_dev, port;

	l_dev = w83627_get_uart_logical_device(uartno);

	w83627_enter_ext_mode();
	outb_p(0x07, WDT_EFIR);			/* Access logical devices */
	outb_p(l_dev, WDT_EFDR);		/* Select the logical device */
	outb_p(0x60, WDT_EFIR);			/* Select CR60 */
	port = inb(WDT_EFDR);
	outb_p(0x61, WDT_EFIR);			/* Select CR61 */
	port = (port << 8) | inb(WDT_EFDR);
	w83627_leave_ext_mode();

	return port;
}

/* 
 * Reads the UART clock source speed
 */
static int w83627_get_uart_clock(int uartno)
{
	int l_dev, clock;

	l_dev = w83627_get_uart_logical_device(uartno);

	w83627_enter_ext_mode();
	outb_p(0x7, WDT_EFIR);			/* Access logical devices */
	outb_p(l_dev, WDT_EFDR);		/* Select the locical device */
	outb_p(0xf0, WDT_EFIR);			/* Select CRF0 */
	clock = inb(WDT_EFDR);	
	w83627_leave_ext_mode();

	return (clock & 0x2);
}

/*
 * Sets the UART clock speed
 */
static void w83627_set_uart_clock(int speed, int uartno)
{
	int l_dev, clock;

	l_dev = w83627_get_uart_logical_device(uartno);
	if (speed < 0 || speed > 0x3) {
		printk(KERN_ERR "Invalid clock speed specified\n");
		return;
	}

	w83627_enter_ext_mode();
	outb_p(0x7, WDT_EFIR);			/* Access logical devices */
	outb_p(l_dev, WDT_EFDR);		/* Select the desired device */
	outb_p(0xf0, WDT_EFIR);			/* Select CRF0 */
	clock = inb(WDT_EFDR);
	clock &= ~0x2;
	//clock |= WDT_CLOCK_2400000;
	clock |= WDT_CLOCK_1476000;
	outb_p(clock, WDT_EFDR);	
	w83627_leave_ext_mode();
}

/*
 * Tries to find out where the w83627 chip is located
 */
static int w83627_detect(void)
{
	int hefras, port = 0;

	w83627_enter_ext_mode();
	outb_p(0x26, WDT_EFIR);			/* Select CR26 */
	hefras = inb(WDT_EFDR);			/* Read from CR26 */
	w83627_leave_ext_mode();
	printk(KERN_INFO "hefras: 0x%x\n", hefras);
	return port;
}

/*
 * Sets the UART serial speed
 */
static void w83627_set_serial(void)
{
	int port = 0, clock;

	port = w83627_get_uart_port(WDT_UART1);
	if (!port) {
		printk(KERN_ERR "UART port not specified, aborting\n");
		return;
	}
	printk(KERN_INFO "Uart port address seems to be: 0x%x\n", port);
	clock = w83627_get_uart_clock(WDT_UART0);	/* UART 0 clock speed */
	printk(KERN_INFO "UART 0 clock speed: 0x%x\n", clock);
	w83627_set_uart_clock(WDT_CLOCK_2400000,0);
	clock = w83627_get_uart_clock(WDT_UART0);	/* UART 0 clock speed */
	printk(KERN_INFO "UART 0 clock speed: 0x%x\n", clock);

	w83627_enter_bdlab_mode(port);
	w83627_get_baud_divisor(port);
	w83627_set_baud_divisor(0x100, port);
	w83627_get_baud_divisor(port);
	w83627_leave_bdlab_mode(port);
}

#ifdef MODULE

#define w83627_init init_module

#endif

int __init w83627_init(void)
{
	printk(KERN_INFO "W83627HF fast serial port driver 0.1 loaded\n");
	w83627_set_serial();
	return 0;
}

MODULE_LICENSE("GPL");

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