#if defined(CONFIG_SERIAL_SAMSUNG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "samsung.h"
/* UART name and device definitions */
//将用来初始化 tty_driver->major,tty_driver->minor_start,tty_driver->driver_name
#define S3C24XX_SERIAL_NAME "ttySAC"
#define S3C24XX_SERIAL_MAJOR 204
#define S3C24XX_SERIAL_MINOR 64
/* macros to change one thing to another */
//数据发送接收功能的使能和禁能标识
#define tx_enabled(port) ((port)->unused[0])
#define rx_enabled(port) ((port)->unused[1])
/* flag to ignore all characters comming in */
#define RXSTAT_DUMMY_READ (0x10000000)//忽略所有的状态标志
//获取结构体s3c24xx_uart_port
static inline struct s3c24xx_uart_port *to_ourport(struct uart_port *port)
{
return container_of(port, struct s3c24xx_uart_port, port);
}
/* translate a port to the device name */
//获取平台设备的设备名
static inline const char *s3c24xx_serial_portname(struct uart_port *port)
{
return to_platform_device(port->dev)->name;
}
//发送缓存和移位缓存都为空返回1否则返回0
static int s3c24xx_serial_txempty_nofifo(struct uart_port *port)
{
return (rd_regl(port, S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXE);
}
//接收使能
static void s3c24xx_serial_rx_enable(struct uart_port *port)
{
unsigned long flags;
unsigned int ucon, ufcon;
int count = 10000;
spin_lock_irqsave(&port->lock, flags);
while (--count && !s3c24xx_serial_txempty_nofifo(port))
udelay(100);//如果还有未发送的数据则等待发送结束
ufcon = rd_regl(port, S3C2410_UFCON);
ufcon |= S3C2410_UFCON_RESETRX;//复位接收fifo
wr_regl(port, S3C2410_UFCON, ufcon);
ucon = rd_regl(port, S3C2410_UCON);
ucon |= S3C2410_UCON_RXIRQMODE;
wr_regl(port, S3C2410_UCON, ucon);
rx_enabled(port) = 1;//置接收使能标识
spin_unlock_irqrestore(&port->lock, flags);
}
//数据接收功能禁能
static void s3c24xx_serial_rx_disable(struct uart_port *port)
{
unsigned long flags;
unsigned int ucon;
spin_lock_irqsave(&port->lock, flags);
ucon = rd_regl(port, S3C2410_UCON);
ucon &= ~S3C2410_UCON_RXIRQMODE;
wr_regl(port, S3C2410_UCON, ucon);
rx_enabled(port) = 0;
spin_unlock_irqrestore(&port->lock, flags);
}
static void s3c24xx_serial_stop_tx(struct uart_port *port)
{
struct s3c24xx_uart_port *ourport = to_ourport(port);
if (tx_enabled(port)) {
disable_irq_nosync(ourport->tx_irq);//停止发送既是禁止发送中断
tx_enabled(port) = 0;//清零发送标识
if (port->flags & UPF_CONS_FLOW)
s3c24xx_serial_rx_enable(port);//
}
}
static void s3c24xx_serial_start_tx(struct uart_port *port)
{
struct s3c24xx_uart_port *ourport = to_ourport(port);
if (!tx_enabled(port)) {
if (port->flags & UPF_CONS_FLOW)
s3c24xx_serial_rx_disable(port);//
enable_irq(ourport->tx_irq);//使能数据传送既是使能发送中断
tx_enabled(port) = 1;//置发送使能标识
}
}
static void s3c24xx_serial_stop_rx(struct uart_port *port)
{
struct s3c24xx_uart_port *ourport = to_ourport(port);
if (rx_enabled(port)) {
dbg("s3c24xx_serial_stop_rx: port=%p\n", port);
disable_irq_nosync(ourport->rx_irq);//停止数据传输既是禁止接收中断
rx_enabled(port) = 0;//清零接收使能标识
}
}
static void s3c24xx_serial_enable_ms(struct uart_port *port)
{
}
//获取结构体 s3c24xx_uart_info
static inline struct s3c24xx_uart_info *s3c24xx_port_to_info(struct uart_port *port)
{
return to_ourport(port)->info;
}
//结构体s3c2410_uartcfg，在文件mach-tq2440.c中初始化
//主要是给这三个寄存器赋初值ucon ,ulcon,ufcon
static inline struct s3c2410_uartcfg *s3c24xx_port_to_cfg(struct uart_port *port)
{
if (port->dev == NULL)
return NULL;
return (struct s3c2410_uartcfg *)port->dev->platform_data;
}
//获取接收fifo中已有的数据个数，结构体s3c24xx_uart_info在文件s3c2440.c中初始化
static int s3c24xx_serial_rx_fifocnt(struct s3c24xx_uart_port *ourport,
unsigned long ufstat)
{
struct s3c24xx_uart_info *info = ourport->info;
if (ufstat & info->rx_fifofull)//如果fifo满
return info->fifosize;
return (ufstat & info->rx_fifomask) >> info->rx_fifoshift;//计算fifo中的数据个数
}
/* ? - where has parity gone?? */
#define S3C2410_UERSTAT_PARITY (0x1000)
static irqreturn_t
s3c24xx_serial_rx_chars(int irq, void *dev_id)
{
struct s3c24xx_uart_port *ourport = dev_id;
struct uart_port *port = &ourport->port;
struct tty_struct *tty = port->info->port.tty;
unsigned int ufcon, ch, flag, ufstat, uerstat;
int max_count = 64;//一次中断接收的最大数据量
while (max_count-- > 0) {
ufcon = rd_regl(port, S3C2410_UFCON);
ufstat = rd_regl(port, S3C2410_UFSTAT);
if (s3c24xx_serial_rx_fifocnt(ourport, ufstat) == 0)//看接收fifo中是否有数据
break;
uerstat = rd_regl(port, S3C2410_UERSTAT);
ch = rd_regb(port, S3C2410_URXH);//读取一个字符
if (port->flags & UPF_CONS_FLOW) {//自动流控制
int txe = s3c24xx_serial_txempty_nofifo(port);
//如果发送器不为空则清零接收标志continue，下一次循环进入else如果发送器为空
//复位接收fifo后置接收标志然后goto out;
if (rx_enabled(port)) {
if (!txe) {
rx_enabled(port) = 0;
continue;
}
} else {
if (txe) {
ufcon |= S3C2410_UFCON_RESETRX;
wr_regl(port, S3C2410_UFCON, ufcon);
rx_enabled(port) = 1;
goto out;
}
continue;
}
}
/* insert the character into the buffer */
flag = TTY_NORMAL;//接收到的是正确的数据
port->icount.rx++;//接收数据个数加
if (unlikely(uerstat & S3C2410_UERSTAT_ANY)) {//判断是否有错误标志被置位,并做相应处理
dbg("rxerr: port ch=0x%02x, rxs=0x%08x\n",
ch, uerstat);
/* check for break */
if (uerstat & S3C2410_UERSTAT_BREAK) {
dbg("break!\n");
port->icount.brk++;
if (uart_handle_break(port))
goto ignore_char;
}
if (uerstat & S3C2410_UERSTAT_FRAME)
port->icount.frame++;
if (uerstat & S3C2410_UERSTAT_OVERRUN)
port->icount.overrun++;
uerstat &= port->read_status_mask;
if (uerstat & S3C2410_UERSTAT_BREAK)
flag = TTY_BREAK;
else if (uerstat & S3C2410_UERSTAT_PARITY)
flag = TTY_PARITY;
else if (uerstat & (S3C2410_UERSTAT_FRAME |
S3C2410_UERSTAT_OVERRUN))
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(port, ch))
goto ignore_char;
/*
struct tty_buffer {
struct tty_buffer *next;//连接指针链表
char *char_buf_ptr;//指向数据缓存
unsigned char *flag_buf_ptr;//指向存放标志的缓存
int used;//该段缓存第一个未被占用的数据位置，该段缓存中数据被读取该值不减
int size;//该段数据缓存的大小
int commit;//该段缓存中最后一次写入时，数据缓存中的数据量，数据被读取时该值不减
int read;//指向第一个未被读取的数据，数据被读取其值加。commit - read表示缓存中的数据量
// Data points here
//缓存被分配时数据存放首地址放于此处，让char_buf_ptr指向这里，
//flag_buf_ptr指向data[0] + (size + 0xFF)处。
unsigned long data[0];
};
将接收到的标志flag放入tty->buf.tail->flag_buf_ptr[tb->used](flag表明数据是否正常在数据读取时查看)，
将数据ch放入tty->buf.tail->char_buf_ptr[tb->used++].
接收数据存放的缓存链由结构体struct tty_bufhead来管理
struct tty_bufhead {
struct delayed_work work;
spinlock_t lock;
struct tty_buffer *head; // Queue head
struct tty_buffer *tail; // Active buffer
struct tty_buffer *free;// Free queue head
int memory_used; //Buffer space used excluding
free queue
};
head指向缓存链的头，在数据读取时从此开始；tail指向缓存链的尾，当数据写入时写到此处；
free指向已被读取数据的缓存。每次存入数据时放到tail指向的缓存，
如果该段缓存已用完将free指向的缓存链中的一段缓存添加到tail。如果
free指向的缓存链没有足够大的缓存或没有缓存，则分配二倍(size + 0xFF)(size为要存入数据的大小)
的缓存分别给tty->buf.tail->flag_buf_ptr和tty->buf.tail->char_buf_ptr，然后挂到tail。
*/
uart_insert_char(port, uerstat, S3C2410_UERSTAT_OVERRUN,
ch, flag);
ignore_char:
continue;
}
/*
将tail指向的数据缓存已被占用的值used赋给commit，tty->buf.tail->commit = tty->buf.tail->used;
调用函数flush_to_ldisc。
flush_to_ldisc：
如果head指向的数据缓存的数据已被完全读取，则将此缓存挂到free上。调用函数disc->ops->receive_buf
disc->ops->receive_buf：
将数据拷贝到读数据缓存器中tty->read_buf，在函数 ld->ops->read 拷贝到用户空间copy_from_read_buf(tty, &b, &nr);
*/
tty_flip_buffer_push(tty);
out:
return IRQ_HANDLED;
}
static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
{
struct s3c24xx_uart_port *ourport = id;
struct uart_port *port = &ourport->port;
struct circ_buf *xmit = &port->info->xmit;
int count = 256;
//当存放接收数据的缓存满或空时xof/fxon，通知设备不要发送更多数据了，或通知设备开始发送数据
if (port->x_char) {//发送特殊字符xon/xoff
wr_regb(port, S3C2410_UTXH, port->x_char);
port->icount.tx++;//数据发送计数加
port->x_char = 0;
goto out;
}
/* if there isnt anything more to transmit, or the uart is now
* stopped, disable the uart and exit
*/
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
s3c24xx_serial_stop_tx(port);//如果存放发送数据的缓存为空
goto out;
}
/* try and drain the buffer... */
while (!uart_circ_empty(xmit) && count-- > 0) {//发送完指定的数据量
if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)
break;
wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);//如果数据缓存中的数据量小于设定值则唤醒写进程
if (uart_circ_empty(xmit))//如果数据缓存中的数据已被全部发送，则停止
s3c24xx_serial_stop_tx(port);
out:
return IRQ_HANDLED;
}
static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port)
{
struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
unsigned long ufstat = rd_regl(port, S3C2410_UFSTAT);
unsigned long ufcon = rd_regl(port, S3C2410_UFCON);
if (ufcon & S3C2410_UFCON_FIFOMODE) {
if ((ufstat & info->tx_fifomask) != 0 ||
(ufstat & info->tx_fifofull))//在使用fifo时fifo中有数据返回0否则返回1
return 0;
return 1;
}
//在不使用fifo时，如果发送器为空返回1否则返回0
return s3c24xx_serial_txempty_nofifo(port);
}
/* no modem control lines */
static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port)
{
unsigned int umstat = rd_regb(port, S3C2410_UMSTAT);
if (umstat & S3C2410_UMSTAT_CTS)//自动流控制模式时判断CTS的状态
return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
else
return TIOCM_CAR | TIOCM_DSR;
}
static void s3c24xx_serial_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
/* todo - possibly remove AFC and do manual CTS */
}
static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state)
{
unsigned long flags;
unsigned int ucon;
spin_lock_irqsave(&port->lock, flags);
ucon = rd_regl(port, S3C2410_UCON);
if (break_state)
ucon |= S3C2410_UCON_SBREAK;//发送终止信号
else
ucon &= ~S3C2410_UCON_SBREAK;//正常发送
wr_regl(port, S3C2410_UCON, ucon);
spin_unlock_irqrestore(&port->lock, flags);
}
//关机
static void s3c24xx_serial_shutdown(struct uart_port *port)
{
struct s3c24xx_uart_port *ourport = to_ourport(port);
if (ourport->tx_claimed) {
free_irq(ourport->tx_irq, ourport);
tx_enabled(port) = 0;
ourport->tx_claimed = 0;
}
if (ourport->rx_claimed) {
free_irq(ourport->rx_irq, ourport);
ourport->rx_claimed = 0;
rx_enabled(port) = 0;
}
}
//中断申请和相应管脚配置
static int s3c24xx_serial_startup(struct uart_port *port)
{
struct s3c24xx_uart_port *ourport = to_ourport(port);
int ret;
dbg("s3c24xx_serial_startup: port=%p (%08lx,%p)\n",
port->mapbase, port->membase);
rx_enabled(port) = 1;
//申请接收中断
ret = request_irq(ourport->rx_irq, s3c24xx_serial_rx_chars, 0,
s3c24xx_serial_portname(port), ourport);
if (ret != 0) {
printk(KERN_ERR "cannot get irq %d\n", ourport->rx_irq);
return ret;
}
ourport->rx_claimed = 1;
dbg("requesting tx irq...\n");
tx_enabled(port) = 1;
//申请发送中断
ret = request_irq(ourport->tx_irq, s3c24xx_serial_tx_chars, 0,
s3c24xx_serial_portname(port), ourport);
if (ret) {
printk(KERN_ERR "cannot get irq %d\n", ourport->tx_irq);
goto err;
}
ourport->tx_claimed = 1;
dbg("s3c24xx_serial_startup ok\n");
//管脚模式设置
/* the port reset code should have done the correct
* register setup for the port controls */
if (port->line == 2) {
s3c2410_gpio_cfgpin(S3C2410_GPH6, S3C2410_GPH6_TXD2);
s3c2410_gpio_pullup(S3C2410_GPH6, 1);
s3c2410_gpio_cfgpin(S3C2410_GPH7, S3C2410_GPH7_RXD2);
s3c2410_gpio_pullup(S3C2410_GPH7, 1);
}
return ret;
err:
s3c24xx_serial_shutdown(port);
return ret;
}
/* power power management control */
//电源管理，关闭接入时钟或是开启接入时钟
static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
unsigned int old)
{
struct s3c24xx_uart_port *ourport = to_ourport(port);
ourport->pm_level = level;
switch (level) {
case 3:
if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)
clk_disable(ourport->baudclk);
clk_disable(ourport->clk);
break;
case 0:
clk_enable(ourport->clk);
if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)
clk_enable(ourport->baudclk);
break;
default:
printk(KERN_ERR "s3c24xx_serial: unknown pm %d\n", level);
}
}
/* baud rate calculation
*
* The UARTs on the S3C2410/S3C2440 can take their clocks from a number
* of different sources, including the peripheral clock ("pclk") and an
* external clock ("uclk"). The S3C2440 also adds the core clock ("fclk")
* with a programmable extra divisor.
*
* The following code goes through the clock sources, and calculates the
* baud clocks (and the resultant actual baud rates) and then tries to
* pick the closest one and select that.
*
*/
#define MAX_CLKS (8)
//时钟管理
static struct s3c24xx_uart_clksrc tmp_clksrc = {
.name = "pclk",
.min_baud = 0,
.max_baud = 0,
.divisor = 1,
};
static inline int
s3c24xx_serial_getsource(struct uart_port *port, struct s3c24xx_uart_clksrc *c)
{
struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
//结构体s3c24xx_uart_info在文件s3c2440.c中初始化，info->get_clksrc在文件s3c2440.c中初始化
return (info->get_clksrc)(port, c);
}
static inline int
s3c24xx_serial_setsource(struct uart_port *port, struct s3c24xx_uart_clksrc *c)
{
struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
//描述同上
return (info->set_clksrc)(port, c);
}
struct baud_calc {
struct s3c24xx_uart_clksrc *clksrc;
unsigned int calc;
unsigned int divslot;
unsigned int quot;
struct clk *src;
};
//计算波特率，并初始化一些结构体的成员，具体实现略。
static int s3c24xx_serial_calcbaud(struct baud_calc *calc,
struct uart_port *port,
struct s3c24xx_uart_clksrc *clksrc,
unsigned int baud)
{
struct s3c24xx_uart_port *ourport = to_ourport(port);
unsigned long rate;
calc->src = clk_get(port->dev, clksrc->name);
if (calc->src == NULL || IS_ERR(calc->src))
return 0;
rate = clk_get_rate(calc->src);
rate /= clksrc->divisor;
calc->clksrc = clksrc;
if (ourport->info->has_divslot) {
unsigned long div = rate / baud;
/* The UDIVSLOT register on the newer UARTs allows us to
* get a divisor adjustment of 1/16th on the baud clock.
*
* We don't keep the UDIVSLOT value (the 16ths we calculated
* by not multiplying the baud by 16) as it is easy enough
* to recalculate.
*/
calc->quot = div / 16;
calc->calc = rate / div;
} else {
calc->quot = (rate + (8 * baud)) / (16 * baud);
calc->calc = (rate / (calc->quot * 16));
}
calc->quot--;
return 1;
}
//该函数主要实现 为clksrc，clk 成员赋新值
static unsigned int s3c24xx_serial_getclk(struct uart_port *port,
struct s3c24xx_uart_clksrc **clksrc,
struct clk **clk,
unsigned int baud)
{
struct s3c2410_uartcfg *cfg = s3c24xx_port_to_cfg(port);
struct s3c24xx_uart_clksrc *clkp;
struct baud_calc res[MAX_CLKS];
struct baud_calc *resptr, *best, *sptr;
int i;
clkp = cfg->clocks;
best = NULL;
if (cfg->clocks_size < 2) {
if (cfg->clocks_size == 0)
clkp = &tmp_clksrc;
/* check to see if we're sourcing fclk, and if so we're
* going to have to update the clock source
*/
if (strcmp(clkp->name, "fclk") == 0) {
struct s3c24xx_uart_clksrc src;
s3c24xx_serial_getsource(port, &src);
/* check that the port already using fclk, and if
* not, then re-select fclk
*/
if (strcmp(src.name, clkp->name) == 0) {
s3c24xx_serial_setsource(port, clkp);
s3c24xx_serial_getsource(port, &src);
}
clkp->divisor = src.divisor;
}
s3c24xx_serial_calcbaud(res, port, clkp, baud);
best = res;
resptr = best + 1;
} else {
resptr = res;
for (i = 0; i < cfg->clocks_size; i++, clkp++) {
if (s3c24xx_serial_calcbaud(resptr, port, clkp, baud))
resptr++;
}
}
/* ok, we now need to select the best clock we found */
if (!best) {
unsigned int deviation = (1<<30)|((1<<30)-1);
int calc_deviation;
for (sptr = res; sptr < resptr; sptr++) {
calc_deviation = baud - sptr->calc;
if (calc_deviation < 0)
calc_deviation = -calc_deviation;
if (calc_deviation < deviation) {
best = sptr;
deviation = calc_deviation;
}
}
}
/* store results to pass back */
*clksrc = best->clksrc;
*clk = best->src;
return best->quot;
}
/* udivslot_table[]
*
* This table takes the fractional value of the baud divisor and gives
* the recommended setting for the UDIVSLOT register.
*/
static u16 udivslot_table[16] = {
[0] = 0x0000,
[1] = 0x0080,
[2] = 0x0808,
[3] = 0x0888,
[4] = 0x2222,
[5] = 0x4924,
[6] = 0x4A52,
[7] = 0x54AA,
[8] = 0x5555,
[9] = 0xD555,
[10] = 0xD5D5,
[11] = 0xDDD5,
[12] = 0xDDDD,
[13] = 0xDFDD,
[14] = 0xDFDF,
[15] = 0xFFDF,
};
/*
设置串口的一些信息 wr_regl(port, S3C2410_ULCON, ulcon);
wr_regl(port, S3C2410_UBRDIV, quot);
wr_regl(port, S3C2410_UMCON, umcon);
在文件serial_core.c中由函数uart_set_options，在该函数中调用了以下函数。
port->ops->set_termios(port, &termios, &dummy);
在函数uart_set_options中对结构体termios的成员c_cflag作了相应设置，在以下
函数中也是根据termios->c_cflag的值对寄存器做相应配置。
在文件tty_ioctl.c中由函数set_termios，在该函数中将用户空间的ktermios考到
内核空间的tty->termios中。 函数set_termios在函数tty_mode_ioctl中被调用。
在本文件注册uart_driver的的函数中分配了 tty_driver结构体内存，并将默认的
termios结构体tty_std_termios赋给 tty_driver->init_termios。
在文件tty_io.c中由函数__tty_open，在该函数中调用函数tty_init_dev，
在函数tty_init_dev中有调用函数tty_driver_install_tty，在这个函数中
调用的函数tty_init_termios中将termios即tty->driver->termios[idx]赋给了tty->termios
*/
static void s3c24xx_serial_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
struct s3c2410_uartcfg *cfg = s3c24xx_port_to_cfg(port);
struct s3c24xx_uart_port *ourport = to_ourport(port);
struct s3c24xx_uart_clksrc *clksrc = NULL;
struct clk *clk = NULL;
unsigned long flags;
unsigned int baud, quot;
unsigned int ulcon;
unsigned int umcon;
unsigned int udivslot = 0;
/*
* We don't support modem control lines.
*/
termios->c_cflag &= ~(HUPCL | CMSPAR);
termios->c_cflag |= CLOCAL;
/*
* Ask the core to calculate the divisor for us.
*/
baud = uart_get_baud_rate(port, termios, old, 0, 115200*8);
if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
quot = port->custom_divisor;
else
quot = s3c24xx_serial_getclk(port, &clksrc, &clk, baud);
/* check to see if we need to change clock source */
if (ourport->clksrc != clksrc || ourport->baudclk != clk) {
dbg("selecting clock %p\n", clk);
s3c24xx_serial_setsource(port, clksrc);
if (ourport->baudclk != NULL && !IS_ERR(ourport->baudclk)) {
clk_disable(ourport->baudclk);
ourport->baudclk = NULL;
}
clk_enable(clk);
ourport->clksrc = clksrc;
ourport->baudclk = clk;
ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0;
}
if (ourport->info->has_divslot) {
unsigned int div = ourport->baudclk_rate / baud;
udivslot = udivslot_table[div & 15];
dbg("udivslot = %04x (div %d)\n", udivslot, div & 15);
}
switch (termios->c_cflag & CSIZE) {
case CS5:
dbg("config: 5bits/char\n");
ulcon = S3C2410_LCON_CS5;
break;
case CS6:
dbg("config: 6bits/char\n");
ulcon = S3C2410_LCON_CS6;
break;
case CS7:
dbg("config: 7bits/char\n");
ulcon = S3C2410_LCON_CS7;
break;
case CS8:
default:
dbg("config: 8bits/char\n");
ulcon = S3C2410_LCON_CS8;
break;
}
/* preserve original lcon IR settings */
ulcon |= (cfg->ulcon & S3C2410_LCON_IRM);
if (termios->c_cflag & CSTOPB)
ulcon |= S3C2410_LCON_STOPB;
umcon = (termios->c_cflag & CRTSCTS) ? S3C2410_UMCOM_AFC : 0;
if (termios->c_cflag & PARENB) {
if (termios->c_cflag & PARODD)
ulcon |= S3C2410_LCON_PODD;
else
ulcon |= S3C2410_LCON_PEVEN;
} else {
ulcon |= S3C2410_LCON_PNONE;
}
spin_lock_irqsave(&port->lock, flags);
dbg("setting ulcon to %08x, brddiv to %d, udivslot %08x\n",
ulcon, quot, udivslot);
wr_regl(port, S3C2410_ULCON, ulcon);
wr_regl(port, S3C2410_UBRDIV, quot);
wr_regl(port, S3C2410_UMCON, umcon);
if (ourport->info->has_divslot)
wr_regl(port, S3C2443_DIVSLOT, udivslot);
dbg("uart: ulcon = 0x%08x, ucon = 0x%08x, ufcon = 0x%08x\n",
rd_regl(port, S3C2410_ULCON),
rd_regl(port, S3C2410_UCON),
rd_regl(port, S3C2410_UFCON));
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
/*
* Which character status flags are we interested in?
*/
port->read_status_mask = S3C2410_UERSTAT_OVERRUN;
if (termios->c_iflag & INPCK)
port->read_status_mask |= S3C2410_UERSTAT_FRAME | S3C2410_UERSTAT_PARITY;
/*
* Which character status flags should we ignore?
*/
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= S3C2410_UERSTAT_OVERRUN;
if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR)
port->ignore_status_mask |= S3C2410_UERSTAT_FRAME;
/*
* Ignore all characters if CREAD is not set.
*/
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= RXSTAT_DUMMY_READ;
spin_unlock_irqrestore(&port->lock, flags);
}
//CPU类型
static const char *s3c24xx_serial_type(struct uart_port *port)
{
switch (port->type) {
case PORT_S3C2410:
return "S3C2410";
case PORT_S3C2440:
return "S3C2440";
case PORT_S3C2412:
return "S3C2412";
case PORT_S3C6400:
return "S3C6400/10";
default:
return NULL;
}
}
#define MAP_SIZE (0x100)
//释放一片内存，在函数s3c24xx_serial_init_port中被指向res->start,res的结构类型为struct resource
static void s3c24xx_serial_release_port(struct uart_port *port)
{
release_mem_region(port->mapbase, MAP_SIZE);
}
//映射一片内存
static int s3c24xx_serial_request_port(struct uart_port *port)
{
const char *name = s3c24xx_serial_portname(port);
return request_mem_region(port->mapbase, MAP_SIZE, name) ? 0 : -EBUSY;
}
//确定CPU类型映射寄存器存储区
static void s3c24xx_serial_config_port(struct uart_port *port, int flags)
{
struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
if (flags & UART_CONFIG_TYPE &&
s3c24xx_serial_request_port(port) == 0)
port->type = info->type;
}
/*
* verify the new serial_struct (for TIOCSSERIAL).
*/
static int
s3c24xx_serial_verify_port(struct uart_port *port, struct serial_struct *ser)
{
struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
if (ser->type != PORT_UNKNOWN && ser->type != info->type)
return -EINVAL;
return 0;
}
#ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE
//申明控制台结构体，该结构体将在下文初始化
static struct console s3c24xx_serial_console;
#define S3C24XX_SERIAL_CONSOLE &s3c24xx_serial_console
#else
#define S3C24XX_SERIAL_CONSOLE NULL
#endif
//该结构体包含了直接针对硬件的操作函数，将会挂到结构体uart_port的成员ops
//uart_port代表一个端口，s3c24xx_serial_ops即是该端口的操作函数
static struct uart_ops s3c24xx_serial_ops = {
.pm = s3c24xx_serial_pm,
.tx_empty = s3c24xx_serial_tx_empty,
.get_mctrl = s3c24xx_serial_get_mctrl,
.set_mctrl = s3c24xx_serial_set_mctrl,
.stop_tx = s3c24xx_serial_stop_tx,
.start_tx = s3c24xx_serial_start_tx,
.stop_rx = s3c24xx_serial_stop_rx,
.enable_ms = s3c24xx_serial_enable_ms,
.break_ctl = s3c24xx_serial_break_ctl,
.startup = s3c24xx_serial_startup,
.shutdown = s3c24xx_serial_shutdown,
.set_termios = s3c24xx_serial_set_termios,
.type = s3c24xx_serial_type,
.release_port = s3c24xx_serial_release_port,
.request_port = s3c24xx_serial_request_port,
.config_port = s3c24xx_serial_config_port,
.verify_port = s3c24xx_serial_verify_port,
};
/*
以下结构是整个串口驱动的核心包含了三个重要结构体：
struct console *cons;//控制台结构体
//一个串口驱动可包含几个端口，因此可有几个uart_state ，
//uart_state的结构内存在函数uart_register_driver中分配
struct uart_state *state;
struct tty_driver *tty_driver;//tty设备驱动的核心结构体
*/
static struct uart_driver s3c24xx_uart_drv = {
.owner = THIS_MODULE,
.dev_name = "tq2440_serial",
.nr = CONFIG_SERIAL_SAMSUNG_UARTS,
.cons = S3C24XX_SERIAL_CONSOLE,
.driver_name = S3C24XX_SERIAL_NAME,
.major = S3C24XX_SERIAL_MAJOR,
.minor = S3C24XX_SERIAL_MINOR,
};
//针对s3c24xx芯片的几个串口
static struct s3c24xx_uart_port s3c24xx_serial_ports[CONFIG_SERIAL_SAMSUNG_UARTS] = {
[0] = {
.port = {
.lock = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[0].port.lock),
.iotype = UPIO_MEM,
.irq = IRQ_S3CUART_RX0,//本端口的接收中断号
.uartclk = 0,
.fifosize = 16,//fifo大小
.ops = &s3c24xx_serial_ops,//本端口的操作函数
.flags = UPF_BOOT_AUTOCONF,
//一个驱动中可能有几个串口，该成员代表本端口在该驱动中的位置，与本端口对应的次设备号有关。
//
.line = 0,
}
},
[1] = {
.port = {
.lock = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[1].port.lock),
.iotype = UPIO_MEM,
.irq = IRQ_S3CUART_RX1,
.uartclk = 0,
.fifosize = 16,
.ops = &s3c24xx_serial_ops,
.flags = UPF_BOOT_AUTOCONF,
.line = 1,
}
},
#if CONFIG_SERIAL_SAMSUNG_UARTS > 2
[2] = {
.port = {
.lock = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[2].port.lock),
.iotype = UPIO_MEM,
.irq = IRQ_S3CUART_RX2,
.uartclk = 0,
.fifosize = 16,
.ops = &s3c24xx_serial_ops,
.flags = UPF_BOOT_AUTOCONF,
.line = 2,
}
},
#endif
#if CONFIG_SERIAL_SAMSUNG_UARTS > 3
[3] = {
.port = {
.lock = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[3].port.lock),
.iotype = UPIO_MEM,
.irq = IRQ_S3CUART_RX3,
.uartclk = 0,
.fifosize = 16,
.ops = &s3c24xx_serial_ops,
.flags = UPF_BOOT_AUTOCONF,
.line = 3,
}
}
#endif
};
/* s3c24xx_serial_resetport
*
* wrapper to call the specific reset for this port (reset the fifos
* and the settings)
*/
static inline int s3c24xx_serial_resetport(struct uart_port *port,
struct s3c2410_uartcfg *cfg)
{
struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
//info->reset_port该函数在文件s3c2440.c中实现
return (info->reset_port)(port, cfg);
}
#ifdef CONFIG_CPU_FREQ
//通知链回调函数，设置波特率
static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,
unsigned long val, void *data)
{
struct s3c24xx_uart_port *port;
struct uart_port *uport;
port = container_of(nb, struct s3c24xx_uart_port, freq_transition);
uport = &port->port;
/* check to see if port is enabled */
if (port->pm_level != 0)
return 0;
/* try and work out if the baudrate is changing, we can detect
* a change in rate, but we do not have support for detecting
* a disturbance in the clock-rate over the change.
*/
if (IS_ERR(port->clk))
goto exit;
if (port->baudclk_rate == clk_get_rate(port->clk))
goto exit;
if (val == CPUFREQ_PRECHANGE) {
/* we should really shut the port down whilst the
* frequency change is in progress. */
} else if (val == CPUFREQ_POSTCHANGE) {
struct ktermios *termios;
struct tty_struct *tty;
if (uport->info == NULL)
goto exit;
tty = uport->info->port.tty;
if (tty == NULL)
goto exit;
termios = tty->termios;
if (termios == NULL) {
printk(KERN_WARNING "%s: no termios?\n", __func__);
goto exit;
}
//设置波特率，将配置值写入相应寄存器
s3c24xx_serial_set_termios(uport, termios, NULL);
}
exit:
return 0;
}
static inline int s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)
{
port->freq_transition.notifier_call = s3c24xx_serial_cpufreq_transition;
//注册通知链
return cpufreq_register_notifier(&port->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
static inline void s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)
{//注销通知链
cpufreq_unregister_notifier(&port->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
#else
static inline int s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)
{
return 0;
}
static inline void s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)
{
}
#endif
/* s3c24xx_serial_init_port
*
* initialise a single serial port from the platform device given
*/
//在函数s3c24xx_serial_init_ports中被调用。建立各结构体的联系，申请中断，IO资源。复位端口
static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
struct s3c24xx_uart_info *info,
struct platform_device *platdev)
{
struct uart_port *port = &ourport->port;
struct s3c2410_uartcfg *cfg;
struct resource *res;
int ret;
dbg("s3c24xx_serial_init_port: port=%p, platdev=%p\n", port, platdev);
if (platdev == NULL)
return -ENODEV;
//获取cfg，该结构在文件mach-tq2440中定义。在文件S3C244x.c中有一个
//初始化函数 s3c244x_init_uarts，在该函数中调用函数s3c24xx_init_uartdevs
//在该函数中将cfg挂到platdev->dev.platform_data上。
cfg = s3c24xx_dev_to_cfg(&platdev->dev);
if (port->mapbase != 0)
return 0;
if (cfg->hwport > CONFIG_SERIAL_SAMSUNG_UARTS) {
printk(KERN_ERR "%s: port %d bigger than %d\n", __func__,
cfg->hwport, CONFIG_SERIAL_SAMSUNG_UARTS);
return -ERANGE;
}
/* setup info for port */
port->dev = &platdev->dev;//让端口uart_port的成员dev指向平台设备
//ourport的结构体类型为struct s3c24xx_uart_port不是uart_port。
//此处的info的结构体类型为s3c24xx_uart_info在文件s3c2440.c 中定义，初始化。不是uart_info。
ourport->info = info;
/* copy the info in from provided structure */
ourport->port.fifosize = info->fifosize;
dbg("s3c24xx_serial_init_port: %p (hw %d)...\n", port, cfg->hwport);
port->uartclk = 1;
if (cfg->uart_flags & UPF_CONS_FLOW) {
dbg("s3c24xx_serial_init_port: enabling flow control\n");
port->flags |= UPF_CONS_FLOW;
}
/* sort our the physical and virtual addresses for each UART */
//获取IO内存
res = platform_get_resource(platdev, IORESOURCE_MEM, 0);
if (res == NULL) {
printk(KERN_ERR "failed to find memory resource for uart\n");
return -EINVAL;
}
dbg("resource %p (%lx..%lx)\n", res, res->start, res->end);
//在上面函数s3c24xx_serial_request_port中映射到虚拟地址
port->mapbase = res->start;
port->membase = S3C_VA_UART + res->start - (S3C_PA_UART & 0xfff00000);
//s3c2410_uart0_resource结构在文件devs.c中定义，初始化。在该文件中没有中断号为
//tx_irq的resource，只有中断号为rx_irq的resource，因为tx_irq = rx_irq + 1；
//因此platform_get_irq(platdev, 1);的返回必然为空
ret = platform_get_irq(platdev, 0);
if (ret < 0)
port->irq = 0;
else {
port->irq = ret;
ourport->rx_irq = ret;
ourport->tx_irq = ret + 1;
}
ret = platform_get_irq(platdev, 1);//返回空
if (ret > 0)
ourport->tx_irq = ret;
ourport->clk = clk_get(&platdev->dev, "uart");//获取名为"uart"的clk
dbg("port: map=%08x, mem=%08x, irq=%d (%d,%d), clock=%ld\n",
port->mapbase, port->membase, port->irq,
ourport->rx_irq, ourport->tx_irq, port->uartclk);
/* reset the fifos (and setup the uart) */
//调用函数info->reset_port复位串口，该函数在文件s3c2440.c中实现
s3c24xx_serial_resetport(port, cfg);
return 0;
}
//属性显示
static ssize_t s3c24xx_serial_show_clksrc(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct uart_port *port = s3c24xx_dev_to_port(dev);
struct s3c24xx_uart_port *ourport = to_ourport(port);
return snprintf(buf, PAGE_SIZE, "* %s\n", ourport->clksrc->name);
}
static DEVICE_ATTR(clock_source, S_IRUGO, s3c24xx_serial_show_clksrc, NULL);//设备属性
/* Device driver serial port probe */
static int probe_index;//为端口在数组s3c24xx_serial_ports中的索引
//以下函数在文件S3C2440.c中的函数s3c2440_serial_probe中调用
int s3c24xx_serial_probe(struct platform_device *dev,
struct s3c24xx_uart_info *info)
{
struct s3c24xx_uart_port *ourport;
int ret;
dbg("s3c24xx_serial_probe(%p, %p) %d\n", dev, info, probe_index);
ourport = &s3c24xx_serial_ports[probe_index];
probe_index++;
dbg("%s: initialising port %p...\n", __func__, ourport);
//建立各结构体的联系，申请中断，IO资源。复位端口
ret = s3c24xx_serial_init_port(ourport, info, dev);
if (ret < 0)
goto probe_err;
dbg("%s: adding port\n", __func__);
//配置端口，构造与本端口对应的设备节点
uart_add_one_port(&s3c24xx_uart_drv, &ourport->port);
platform_set_drvdata(dev, &ourport->port);//将ourport->port设为平台设备的drvdata
ret = device_create_file(&dev->dev, &dev_attr_clock_source);//创建文件属性
if (ret < 0)
printk(KERN_ERR "%s: failed to add clksrc attr.\n", __func__);
/*
注册通知链，当CPU频率改变时调用函数s3c24xx_serial_cpufreq_transition，最终调用函数
s3c24xx_serial_set_termios设置波特率等
*/
ret = s3c24xx_serial_cpufreq_register(ourport);
if (ret < 0)
dev_err(&dev->dev, "failed to add cpufreq notifier\n");
return 0;
probe_err:
return ret;
}
EXPORT_SYMBOL_GPL(s3c24xx_serial_probe);
int s3c24xx_serial_remove(struct platform_device *dev)
{
struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);
if (port) {
s3c24xx_serial_cpufreq_deregister(to_ourport(port));
device_remove_file(&dev->dev, &dev_attr_clock_source);
uart_remove_one_port(&s3c24xx_uart_drv, port);
}
return 0;
}
EXPORT_SYMBOL_GPL(s3c24xx_serial_remove);
/* UART power management code */
#ifdef CONFIG_PM
static int s3c24xx_serial_suspend(struct platform_device *dev, pm_message_t state)
{
struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);
if (port)
uart_suspend_port(&s3c24xx_uart_drv, port);
return 0;
}
static int s3c24xx_serial_resume(struct platform_device *dev)
{
struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);
struct s3c24xx_uart_port *ourport = to_ourport(port);
if (port) {
clk_enable(ourport->clk);
s3c24xx_serial_resetport(port, s3c24xx_port_to_cfg(port));
clk_disable(ourport->clk);
uart_resume_port(&s3c24xx_uart_drv, port);
}
return 0;
}
#endif
/*
驱动结构在文件s3c2440.c中定义并初始化。
static struct platform_driver s3c2440_serial_drv = {
.probe = s3c2440_serial_probe,
.remove = s3c24xx_serial_remove,
.driver = {
.name = "s3c2440-uart",
.owner = THIS_MODULE,
},
};
以下函数在文件s3c2440.c中的函数s3c2440_serial_init中调用
*/
int s3c24xx_serial_init(struct platform_driver *drv,
struct s3c24xx_uart_info *info)
{
dbg("s3c24xx_serial_init(%p,%p)\n", drv, info);
#ifdef CONFIG_PM
drv->suspend = s3c24xx_serial_suspend;
drv->resume = s3c24xx_serial_resume;
#endif
return platform_driver_register(drv);
}
EXPORT_SYMBOL_GPL(s3c24xx_serial_init);
/* module initialisation code */
static int __init s3c24xx_serial_modinit(void)
{
int ret;
//注册基于CPU s3c24xx的串口驱动，做各种重要的内存分配和结构的初始化
//本次注册与硬件无关，不进行硬件的配置或是资源的获取。
ret = uart_register_driver(&s3c24xx_uart_drv);
if (ret < 0) {
printk(KERN_ERR "failed to register UART driver\n");
return -1;
}
return 0;
}
static void __exit s3c24xx_serial_modexit(void)
{
uart_unregister_driver(&s3c24xx_uart_drv);
}
module_init(s3c24xx_serial_modinit);
module_exit(s3c24xx_serial_modexit);
/* Console code */
#ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE
static struct uart_port *cons_uart;
static int
s3c24xx_serial_console_txrdy(struct uart_port *port, unsigned int ufcon)
{
struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
unsigned long ufstat, utrstat;
if (ufcon & S3C2410_UFCON_FIFOMODE) {
/* fifo mode - check ammount of data in fifo registers... */
ufstat = rd_regl(port, S3C2410_UFSTAT);
return (ufstat & info->tx_fifofull) ? 0 : 1;
}
/* in non-fifo mode, we go and use the tx buffer empty */
utrstat = rd_regl(port, S3C2410_UTRSTAT);
return (utrstat & S3C2410_UTRSTAT_TXE) ? 1 : 0;
}
static void
s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
{
unsigned int ufcon = rd_regl(cons_uart, S3C2410_UFCON);
while (!s3c24xx_serial_console_txrdy(port, ufcon))
barrier();//发送器非空则等待发送结束
wr_regb(cons_uart, S3C2410_UTXH, ch);//写一个数
}
//写一个字符串
static void
s3c24xx_serial_console_write(struct console *co, const char *s,
unsigned int count)
{
uart_console_write(cons_uart, s, count, s3c24xx_serial_console_putchar);
}
//获取端口的数据位数，校验方式，波特率等。
static void __init
s3c24xx_serial_get_options(struct uart_port *port, int *baud,
int *parity, int *bits)
{
struct s3c24xx_uart_clksrc clksrc;
struct clk *clk;
unsigned int ulcon;
unsigned int ucon;
unsigned int ubrdiv;
unsigned long rate;
ulcon = rd_regl(port, S3C2410_ULCON);
ucon = rd_regl(port, S3C2410_UCON);
ubrdiv = rd_regl(port, S3C2410_UBRDIV);
dbg("s3c24xx_serial_get_options: port=%p\n"
"registers: ulcon=%08x, ucon=%08x, ubdriv=%08x\n",
port, ulcon, ucon, ubrdiv);
if ((ucon & 0xf) != 0) {
/* consider the serial port configured if the tx/rx mode set */
switch (ulcon & S3C2410_LCON_CSMASK) {
case S3C2410_LCON_CS5:
*bits = 5;
break;
case S3C2410_LCON_CS6:
*bits = 6;
break;
case S3C2410_LCON_CS7:
*bits = 7;
break;
default:
case S3C2410_LCON_CS8:
*bits = 8;
break;
}
switch (ulcon & S3C2410_LCON_PMASK) {
case S3C2410_LCON_PEVEN:
*parity = 'e';
break;
case S3C2410_LCON_PODD:
*parity = 'o';
break;
case S3C2410_LCON_PNONE:
default:
*parity = 'n';
}
/* now calculate the baud rate */
s3c24xx_serial_getsource(port, &clksrc);
clk = clk_get(port->dev, clksrc.name);
if (!IS_ERR(clk) && clk != NULL)
rate = clk_get_rate(clk) / clksrc.divisor;
else
rate = 1;
*baud = rate / (16 * (ubrdiv + 1));
dbg("calculated baud %d\n", *baud);
}
}
/* s3c24xx_serial_init_ports
*
* initialise the serial ports from the machine provided initialisation
* data.
*/
static int s3c24xx_serial_init_ports(struct s3c24xx_uart_info *info)
{
struct s3c24xx_uart_port *ptr = s3c24xx_serial_ports;
struct platform_device **platdev_ptr;
int i;
dbg("s3c24xx_serial_init_ports: initialising ports...\n");
platdev_ptr = s3c24xx_uart_devs;
for (i = 0; i < CONFIG_SERIAL_SAMSUNG_UARTS; i++, ptr++, platdev_ptr++) {
s3c24xx_serial_init_port(ptr, info, *platdev_ptr);//端口的初始化
}
return 0;
}
static int __init
s3c24xx_serial_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
dbg("s3c24xx_serial_console_setup: co=%p (%d), %s\n",
co, co->index, options);
/* is this a valid port */
//s3c24xx_serial_console在下面初始化，co->index 初始化为-1，即是默认将第一个端口作为控制台
if (co->index == -1 || co->index >= CONFIG_SERIAL_SAMSUNG_UARTS)
co->index = 0;
//获取整个驱动中作为控制台的那个端口
port = &s3c24xx_serial_ports[co->index].port;
/* is the port configured? */
if (port->mapbase == 0x0) {
co->index = 0;
port = &s3c24xx_serial_ports[co->index].port;
}
cons_uart = port;
dbg("s3c24xx_serial_console_setup: port=%p (%d)\n", port, co->index);
/*
* Check whether an invalid uart number has been specified, and
* if so, search for the first available port that does have
* console support.
*/
//获取波特率，校验方式，数据位，流控制
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
s3c24xx_serial_get_options(port, &baud, &parity, &bits);
dbg("s3c24xx_serial_console_setup: baud %d\n", baud);
//设置波特率，校验方式，数据位，流控制
return uart_set_options(port, co, baud, parity, bits, flow);
}
/* s3c24xx_serial_initconsole
*
* initialise the console from one of the uart drivers
*/
//初始化控制台，在上面初始化结构体s3c24xx_uart_drv时，控制台结构将被挂到
//s3c24xx_uart_drv的cons成员上，在函数uart_add_one_port中将会让端口结构体uart_port
//的成员cons指向该控制台结构体
static struct console s3c24xx_serial_console = {
.name = S3C24XX_SERIAL_NAME,
.device = uart_console_device,
.flags = CON_PRINTBUFFER,
.index = -1,
.write = s3c24xx_serial_console_write,
.setup = s3c24xx_serial_console_setup
};
int s3c24xx_serial_initconsole(struct platform_driver *drv,
struct s3c24xx_uart_info *info)
{//每个端口有一个对应的平台设备对应，在文件devs.c中初始化
struct platform_device *dev = s3c24xx_uart_devs[0];
dbg("s3c24xx_serial_initconsole\n");
/* select driver based on the cpu */
if (dev == NULL) {
printk(KERN_ERR "s3c24xx: no devices for console init\n");
return 0;
}
if (strcmp(dev->name, drv->driver.name) != 0)
return 0;
//将给予CPU 为s3c24xx的串口驱动挂到s3c24xx_serial_console.data上
s3c24xx_serial_console.data = &s3c24xx_uart_drv;
//初始化本驱动中的所有端口，
//建立与各个端口相关的各结构体间的联系，申请中断，IO资源。复位端口
s3c24xx_serial_init_ports(info);
//注册控制台
register_console(&s3c24xx_serial_console);
return 0;
}
#endif /* CONFIG_SERIAL_SAMSUNG_CONSOLE */
MODULE_DESCRIPTION("Samsung SoC Serial port driver");
MODULE_AUTHOR("Ben Dooks <>");
MODULE_LICENSE("GPL v2");
