求一个字符设备的驱动，要求是一个文件的。

wide288 · 发表于 2003-9-3 08:16:04

我想找一个简单些，但实际的字符设备驱动的例子。来看看。由于我没看过内核，没有找到。
最好是一个文件。我在读书上的例子，大部分都是说散了的。如：
----------------------
写版本号的什么宏或#include语句。
为file_operations结构写函数调用。
看起来不难的。可是没有一个像完整的例子。
-----------------------
所以来这请朋友们帮一下忙。谢谢了。

linos · 发表于 2003-9-3 14:55:39

老大你也要写驱动了
兄弟正在痛苦中
到内核中找点来看吧,先看点简单的(键盘,鼠标之类的)
要不就看ldd2,还有它的源码:ftp://ftp.ora.com/pub/examples/linux/drivers(我已经下了,而且编译了几个,可以实用的哦!)
痛苦ing,郁闷ing!
希望能探讨探讨,共同进步.

btw:linuxforum上有个linux device driver版
但是上面的高手好象都不怎么喜欢回答问题

wide288 · 发表于 2003-9-3 20:30:16

是的，那的高手都没有时间。很高兴能与你聊这方面的问题。

wide288 · 发表于 2003-9-4 13:26:44

我对鼠标，键盘不是了解，所以我想从串口，并口这方面来写点什么，或找个例子看。这方面还可以自己找点硬件来试试。

wide288 · 发表于 2003-9-4 14:11:55

/*
* linux/drivers/char/serial_21285.c
*
* Driver for the serial port on the 21285 StrongArm-110 core logic chip.
*
* Based on drivers/char/serial.c
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/major.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/console.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/dec21285.h>
#include <asm/hardware.h>
#define BAUD_BASE (mem_fclk_21285/64)
#define SERIAL_21285_NAME "ttyFB"
#define SERIAL_21285_MAJOR 204
#define SERIAL_21285_MINOR 4
#define SERIAL_21285_AUXNAME "cuafb"
#define SERIAL_21285_AUXMAJOR 205
#define SERIAL_21285_AUXMINOR 4
static struct tty_driver rs285_driver, callout_driver;
static int rs285_refcount;
static struct tty_struct *rs285_table[1];
static struct termios *rs285_termios[1];
static struct termios *rs285_termios_locked[1];
static char wbuf[1000], *putp = wbuf, *getp = wbuf, x_char;
static struct tty_struct *rs285_tty;
static int rs285_use_count;
static int rs285_write_room(struct tty_struct *tty)
{
return putp >= getp ? (sizeof(wbuf) - (long) putp + (long) getp) : ((long) getp - (long) putp - 1);
}
static void rs285_rx_int(int irq, void *dev_id, struct pt_regs *regs)
{
if (!rs285_tty) {
disable_irq(IRQ_CONRX);
return;
}
while (!(*CSR_UARTFLG & 0x10)) {
int ch, flag;
ch = *CSR_UARTDR;
flag = *CSR_RXSTAT;
if (flag & 4)
tty_insert_flip_char(rs285_tty, 0, TTY_OVERRUN);
if (flag & 2)
flag = TTY_PARITY;
else if (flag & 1)
flag = TTY_FRAME;
tty_insert_flip_char(rs285_tty, ch, flag);
}
tty_flip_buffer_push(rs285_tty);
}
static void rs285_send_xchar(struct tty_struct *tty, char ch)
{
x_char = ch;
enable_irq(IRQ_CONTX);
}
static void rs285_throttle(struct tty_struct *tty)
{
if (I_IXOFF(tty))
rs285_send_xchar(tty, STOP_CHAR(tty));
}
static void rs285_unthrottle(struct tty_struct *tty)
{
if (I_IXOFF(tty)) {
if (x_char)
x_char = 0;
else
rs285_send_xchar(tty, START_CHAR(tty));
}
}
static void rs285_tx_int(int irq, void *dev_id, struct pt_regs *regs)
{
while (!(*CSR_UARTFLG & 0x20)) {
if (x_char) {
*CSR_UARTDR = x_char;
x_char = 0;
continue;
}
if (putp == getp) {
disable_irq(IRQ_CONTX);
break;
}
*CSR_UARTDR = *getp;
if (++getp >= wbuf + sizeof(wbuf))
getp = wbuf;
}
if (rs285_tty)
wake_up_interruptible(&rs285_tty->write_wait);
}
static inline int rs285_xmit(int ch)
{
if (putp + 1 == getp || (putp + 1 == wbuf + sizeof(wbuf) && getp == wbuf))
return 0;
*putp = ch;
if (++putp >= wbuf + sizeof(wbuf))
putp = wbuf;
enable_irq(IRQ_CONTX);
return 1;
}
static int rs285_write(struct tty_struct *tty, int from_user,
const u_char * buf, int count)
{
int i;
if (from_user && verify_area(VERIFY_READ, buf, count))
return -EINVAL;
for (i = 0; i < count; i++) {
char ch;
if (from_user)
__get_user(ch, buf + i);
else
ch = buf[i];
if (!rs285_xmit(ch))
break;
}
return i;
}
static void rs285_put_char(struct tty_struct *tty, u_char ch)
{
rs285_xmit(ch);
}
static int rs285_chars_in_buffer(struct tty_struct *tty)
{
return sizeof(wbuf) - rs285_write_room(tty);
}
static void rs285_flush_buffer(struct tty_struct *tty)
{
disable_irq(IRQ_CONTX);
putp = getp = wbuf;
if (x_char)
enable_irq(IRQ_CONTX);
}
static inline void rs285_set_cflag(int cflag)
{
int h_lcr, baud, quot;
switch (cflag & CSIZE) {
case CS5:
h_lcr = 0x10;
break;
case CS6:
h_lcr = 0x30;
break;
case CS7:
h_lcr = 0x50;
break;
default: /* CS8 */
h_lcr = 0x70;
break;
}
if (cflag & CSTOPB)
h_lcr |= 0x08;
if (cflag & PARENB)
h_lcr |= 0x02;
if (!(cflag & PARODD))
h_lcr |= 0x04;
switch (cflag & CBAUD) {
case B200: baud = 200; break;
case B300: baud = 300; break;
case B1200: baud = 1200; break;
case B1800: baud = 1800; break;
case B2400: baud = 2400; break;
case B4800: baud = 4800; break;
default:
case B9600: baud = 9600; break;
case B19200: baud = 19200; break;
case B38400: baud = 38400; break;
case B57600: baud = 57600; break;
case B115200: baud = 115200; break;
}
/*
* The documented expression for selecting the divisor is:
* BAUD_BASE / baud - 1
* However, typically BAUD_BASE is not divisible by baud, so
* we want to select the divisor that gives us the minimum
* error. Therefore, we want:
* int(BAUD_BASE / baud - 0.5) ->
* int(BAUD_BASE / baud - (baud >> 1) / baud) ->
* int((BAUD_BASE - (baud >> 1)) / baud)
*/
quot = (BAUD_BASE - (baud >> 1)) / baud;
*CSR_UARTCON = 0;
*CSR_L_UBRLCR = quot & 0xff;
*CSR_M_UBRLCR = (quot >> 8) & 0x0f;
*CSR_H_UBRLCR = h_lcr;
*CSR_UARTCON = 1;
}
static void rs285_set_termios(struct tty_struct *tty, struct termios *old)
{
if (old && tty->termios->c_cflag == old->c_cflag)
return;
rs285_set_cflag(tty->termios->c_cflag);
}
static void rs285_stop(struct tty_struct *tty)
{
disable_irq(IRQ_CONTX);
}
static void rs285_start(struct tty_struct *tty)
{
enable_irq(IRQ_CONTX);
}
static void rs285_wait_until_sent(struct tty_struct *tty, int timeout)
{
int orig_jiffies = jiffies;
while (*CSR_UARTFLG & 8) {
current->state = TASK_INTERRUPTIBLE;
schedule_timeout(1);
if (signal_pending(current))
break;
if (timeout && time_after(jiffies, orig_jiffies + timeout))
break;
}
current->state = TASK_RUNNING;
}
static int rs285_open(struct tty_struct *tty, struct file *filp)
{
int line;
MOD_INC_USE_COUNT;
line = MINOR(tty->device) - tty->driver.minor_start;
if (line) {
MOD_DEC_USE_COUNT;
return -ENODEV;
}
tty->driver_data = NULL;
if (!rs285_tty)
rs285_tty = tty;
enable_irq(IRQ_CONRX);
rs285_use_count++;
return 0;
}
static void rs285_close(struct tty_struct *tty, struct file *filp)
{
if (!--rs285_use_count) {
rs285_wait_until_sent(tty, 0);
disable_irq(IRQ_CONRX);
disable_irq(IRQ_CONTX);
rs285_tty = NULL;
}
MOD_DEC_USE_COUNT;
}
static int __init rs285_init(void)
{
int baud = B9600;
if (machine_is_personal_server())
baud = B57600;
rs285_driver.magic = TTY_DRIVER_MAGIC;
rs285_driver.driver_name = "serial_21285";
rs285_driver.name = SERIAL_21285_NAME;
rs285_driver.major = SERIAL_21285_MAJOR;
rs285_driver.minor_start = SERIAL_21285_MINOR;
rs285_driver.num = 1;
rs285_driver.type = TTY_DRIVER_TYPE_SERIAL;
rs285_driver.subtype = SERIAL_TYPE_NORMAL;
rs285_driver.init_termios = tty_std_termios;
rs285_driver.init_termios.c_cflag = baud | CS8 | CREAD | HUPCL | CLOCAL;
rs285_driver.flags = TTY_DRIVER_REAL_RAW;
rs285_driver.refcount = &rs285_refcount;
rs285_driver.table = rs285_table;
rs285_driver.termios = rs285_termios;
rs285_driver.termios_locked = rs285_termios_locked;
rs285_driver.open = rs285_open;
rs285_driver.close = rs285_close;
rs285_driver.write = rs285_write;
rs285_driver.put_char = rs285_put_char;
rs285_driver.write_room = rs285_write_room;
rs285_driver.chars_in_buffer = rs285_chars_in_buffer;
rs285_driver.flush_buffer = rs285_flush_buffer;
rs285_driver.throttle = rs285_throttle;
rs285_driver.unthrottle = rs285_unthrottle;
rs285_driver.send_xchar = rs285_send_xchar;
rs285_driver.set_termios = rs285_set_termios;
rs285_driver.stop = rs285_stop;
rs285_driver.start = rs285_start;
rs285_driver.wait_until_sent = rs285_wait_until_sent;
callout_driver = rs285_driver;
callout_driver.name = SERIAL_21285_AUXNAME;
callout_driver.major = SERIAL_21285_AUXMAJOR;
callout_driver.subtype = SERIAL_TYPE_CALLOUT;
if (request_irq(IRQ_CONRX, rs285_rx_int, 0, "rs285", NULL))
panic("Couldn't get rx irq for rs285");
if (request_irq(IRQ_CONTX, rs285_tx_int, 0, "rs285", NULL))
panic("Couldn't get tx irq for rs285");
if (tty_register_driver(&rs285_driver))
printk(KERN_ERR "Couldn't register 21285 serial driver\n");
if (tty_register_driver(&callout_driver))
printk(KERN_ERR "Couldn't register 21285 callout driver\n");
return 0;
}
static void __exit rs285_fini(void)
{
unsigned long flags;
int ret;
save_flags(flags);
cli();
ret = tty_unregister_driver(&callout_driver);
if (ret)
printk(KERN_ERR "Unable to unregister 21285 callout driver "
"(%d)\n", ret);
ret = tty_unregister_driver(&rs285_driver);
if (ret)
printk(KERN_ERR "Unable to unregister 21285 driver (%d)\n",
ret);
free_irq(IRQ_CONTX, NULL);
free_irq(IRQ_CONRX, NULL);
restore_flags(flags);
}
module_init(rs285_init);
module_exit(rs285_fini);
#ifdef CONFIG_SERIAL_21285_CONSOLE
/************** console driver *****************/
static void rs285_console_write(struct console *co, const char *s, u_int count)
{
int i;
disable_irq(IRQ_CONTX);
for (i = 0; i < count; i++) {
while (*CSR_UARTFLG & 0x20);
*CSR_UARTDR = s[i];
if (s[i] == '\n') {
while (*CSR_UARTFLG & 0x20);
*CSR_UARTDR = '\r';
}
}
enable_irq(IRQ_CONTX);
}
static kdev_t rs285_console_device(struct console *c)
{
return MKDEV(SERIAL_21285_MAJOR, SERIAL_21285_MINOR);
}
static int __init rs285_console_setup(struct console *co, char *options)
{
int baud = 9600;
int bits = 8;
int parity = 'n';
int cflag = CREAD | HUPCL | CLOCAL;
if (machine_is_personal_server())
baud = 57600;
if (options) {
char *s = options;
baud = simple_strtoul(options, NULL, 10);
while (*s >= '0' && *s <= '9')
s++;
if (*s)
parity = *s++;
if (*s)
bits = *s - '0';
}
/*
* Now construct a cflag setting.
*/
switch (baud) {
case 1200:
cflag |= B1200;
break;
case 2400:
cflag |= B2400;
break;
case 4800:
cflag |= B4800;
break;
case 9600:
cflag |= B9600;
break;
case 19200:
cflag |= B19200;
break;
case 38400:
cflag |= B38400;
break;
case 57600:
cflag |= B57600;
break;
case 115200:
cflag |= B115200;
break;
default:
cflag |= B9600;
break;
}
switch (bits) {
case 7:
cflag |= CS7;
break;
default:
cflag |= CS8;
break;
}
switch (parity) {
case 'o':
case 'O':
cflag |= PARODD;
break;
case 'e':
case 'E':
cflag |= PARENB;
break;
}
co->cflag = cflag;
rs285_set_cflag(cflag);
rs285_console_write(NULL, "\e[2J\e[Hboot ", 12);
if (options)
rs285_console_write(NULL, options, strlen(options));
else
rs285_console_write(NULL, "no options", 10);
rs285_console_write(NULL, "\n", 1);
return 0;
}
static struct console rs285_cons =
{
name: SERIAL_21285_NAME,
write: rs285_console_write,
device: rs285_console_device,
setup: rs285_console_setup,
flags: CON_PRINTBUFFER,
index: -1,
};
void __init rs285_console_init(void)
{
register_console(&rs285_cons);
}
#endif /* CONFIG_SERIAL_21285_CONSOLE */
MODULE_LICENSE("GPL");
EXPORT_NO_SYMBOLS;

复制代码

x11 · 发表于 2003-9-4 14:20:10

wide288，你也不上irc了

wide288 · 发表于 2003-9-4 15:57:16

我也想上啊。可是没有宽带了。家里只能用猫拔号了。debian 下没有我猫的驱动。驱动是rpm的。
现在工作了。时间少了。在单位还没有自己的机器，我也想你们啊。昨天还是21点10分到家的呢。

linos · 发表于 2003-9-5 09:43:46

"Based on drivers/char/serial.c"
先看这个吧,
serial_21285.c是针对特定的芯片的

呵呵,偶也是刚刚上班

wide288 · 发表于 2003-9-5 10:00:52

昨天下午看了，有很多的地方不懂。
如，这个接收字符的函数，是怎么个定义法呢。

drivers/char/serial.c
-------------------------------------
564行
static _INLINE_ void receive_chars(struct async_struct *info, int *status, struct pt_regs *regs)

复制代码

串口还有针对什么片？不就是收发吗？在加上中断。

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求一个字符设备的驱动，要求是一个文件的。

请问这个文件是什么字符设备的驱动，？全吗？