原文連結
#if defined(CONFIG_SERIAL_SAMSUNG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <asm/irq.h>
#include <mach/hardware.h>
#include <mach/map.h>
#include <plat/regs-serial.h>
#include <mach/regs-gpio.h>
#include "samsung.h"
//将用來初始化 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
//資料發送接收功能的使能和禁能辨別
#define tx_enabled(port) ((port)->unused[0])
#define rx_enabled(port) ((port)->unused[1])
#define RXSTAT_DUMMY_READ (0x10000000)//忽略所有的狀态标志
//擷取結構體s3c24xx_uart_port
static inline struct s3c24xx_uart_port *to_ourport(struct uart_port *port)
{
return container_of(port, struct s3c24xx_uart_port, port);
}
//擷取平台裝置的裝置名
static inline const char *s3c24xx_serial_portname(struct uart_port *port)
{
return to_platform_device(port->dev)->name;
}
//發送緩存和移位緩存都為空傳回1否則傳回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);//如果還有未發送的資料則等待發送結束
ufcon = rd_regl(port, S3C2410_UFCON);
ufcon |= S3C2410_UFCON_RESETRX;//複位接收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;//置接收使能辨別
spin_unlock_irqrestore(&port->lock, flags);
}
//資料接收功能禁能
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);//停止發送既是禁止發送中斷
tx_enabled(port) = 0;//清零發送辨別
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);//使能資料傳送既是使能發送中斷
tx_enabled(port) = 1;//置發送使能辨別
}
}
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);//停止資料傳輸既是禁止接收中斷
rx_enabled(port) = 0;//清零接收使能辨別
}
}
static void s3c24xx_serial_enable_ms(struct uart_port *port)
{
}
//擷取結構體 s3c24xx_uart_info
static inline struct s3c24xx_uart_info *s3c24xx_port_to_info(struct uart_port *port)
{
return to_ourport(port)->info;
}
//結構體s3c2410_uartcfg，在檔案mach-tq2440.c中初始化
//主要是給這三個寄存器賦初值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;
}
//擷取接收fifo中已有的資料個數，結構體s3c24xx_uart_info在檔案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滿
return info->fifosize;
return (ufstat & info->rx_fifomask) >> info->rx_fifoshift;//計算fifo中的資料個數
}
#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;//一次中斷接收的最大資料量
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中是否有資料
break;
uerstat = rd_regl(port, S3C2410_UERSTAT);
ch = rd_regb(port, S3C2410_URXH);//讀取一個字元
if (port->flags & UPF_CONS_FLOW) {//自動流控制
int txe = s3c24xx_serial_txempty_nofifo(port);
//如果發送器不為空則清零接收标志continue，下一次循環進入else如果發送器為空
//複位接收fifo後置接收标志然後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;
}
}
flag = TTY_NORMAL;//接收到的是正确的資料
port->icount.rx++;//接收資料個數加
if (unlikely(uerstat & S3C2410_UERSTAT_ANY)) {//判斷是否有錯誤标志被置位,并做相應處理
dbg("rxerr: port ch=0x%02x, rxs=0x%08x\n",
ch, uerstat);
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;
uart_insert_char(port, uerstat, S3C2410_UERSTAT_OVERRUN,
ch, flag);
ignore_char:
continue;
}
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;
//當存放接收資料的緩存滿或空時xof/fxon，通知裝置不要發送更多資料了，或通知裝置開始發送資料
if (port->x_char) {//發送特殊字元xon/xoff
wr_regb(port, S3C2410_UTXH, port->x_char);
port->icount.tx++;//資料發送計數加
port->x_char = 0;
goto out;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
s3c24xx_serial_stop_tx(port);//如果存放發送資料的緩存為空
goto out;
}
while (!uart_circ_empty(xmit) && count-- > 0) {//發送完指定的資料量
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);//如果資料緩存中的資料量小于設定值則喚醒寫程序
if (uart_circ_empty(xmit))//如果資料緩存中的資料已被全部發送，則停止
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時fifo中有資料傳回0否則傳回1
return 0;
return 1;
}
//在不使用fifo時，如果發送器為空傳回1否則傳回0
return s3c24xx_serial_txempty_nofifo(port);
}
static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port)
{
unsigned int umstat = rd_regb(port, S3C2410_UMSTAT);
if (umstat & S3C2410_UMSTAT_CTS)//自動流控制模式時判斷CTS的狀态
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)
{
}
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;//發送終止信号
else
ucon &= ~S3C2410_UCON_SBREAK;//正常發送
wr_regl(port, S3C2410_UCON, ucon);
spin_unlock_irqrestore(&port->lock, flags);
}
//關機
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;
}
}
//中斷申請和相應管腳配置
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;
//申請接收中斷
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;
//申請發送中斷
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");
//管腳模式設定
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;
}
//電源管理，關閉接入時鐘或是開啟接入時鐘
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);
}
}
#define MAX_CLKS (8)
//時鐘管理
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);
//結構體s3c24xx_uart_info在檔案s3c2440.c中初始化，info->get_clksrc在檔案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;
};
//計算波特率，并初始化一些結構體的成員，具體實作略。
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;
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;
}
//該函數主要實作 為clksrc，clk 成員賦新值
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;
if (strcmp(clkp->name, "fclk") == 0) {
struct s3c24xx_uart_clksrc src;
s3c24xx_serial_getsource(port, &src);
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++;
}
}
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;
}
}
}
*clksrc = best->clksrc;
*clk = best->src;
return best->quot;
}
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,
};
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;
termios->c_cflag &= ~(HUPCL | CMSPAR);
termios->c_cflag |= CLOCAL;
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);
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;
}
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));
uart_update_timeout(port, termios->c_cflag, baud);
port->read_status_mask = S3C2410_UERSTAT_OVERRUN;
if (termios->c_iflag & INPCK)
port->read_status_mask |= S3C2410_UERSTAT_FRAME | S3C2410_UERSTAT_PARITY;
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;
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= RXSTAT_DUMMY_READ;
spin_unlock_irqrestore(&port->lock, flags);
}
//CPU類型
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)
//釋放一片記憶體，在函數s3c24xx_serial_init_port中被指向res->start,res的結構類型為struct resource
static void s3c24xx_serial_release_port(struct uart_port *port)
{
release_mem_region(port->mapbase, MAP_SIZE);
}
//映射一片記憶體
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類型映射寄存器存儲區
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;
}
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
//申明控制台結構體，該結構體将在下文初始化
static struct console s3c24xx_serial_console;
#define S3C24XX_SERIAL_CONSOLE &s3c24xx_serial_console
#else
#define S3C24XX_SERIAL_CONSOLE NULL
#endif
//該結構體包含了直接針對硬體的操作函數，将會挂到結構體uart_port的成員ops
//uart_port代表一個端口，s3c24xx_serial_ops即是該端口的操作函數
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,
};
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,
};
//針對s3c24xx晶片的幾個序列槽
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,//本端口的接收中斷号
.uartclk = 0,
.fifosize = 16,//fifo大小
.ops = &s3c24xx_serial_ops,//本端口的操作函數
.flags = UPF_BOOT_AUTOCONF,
//一個驅動中可能有幾個序列槽，該成員代表本端口在該驅動中的位置，與本端口對應的次裝置号有關。
//
.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
};
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該函數在檔案s3c2440.c中實作
return (info->reset_port)(port, cfg);
}
#ifdef CONFIG_CPU_FREQ
//通知鍊回調函數，設定波特率
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;
if (port->pm_level != 0)
return 0;
if (IS_ERR(port->clk))
goto exit;
if (port->baudclk_rate == clk_get_rate(port->clk))
goto exit;
if (val == CPUFREQ_PRECHANGE) {
} 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;
}
//設定波特率，将配置值寫入相應寄存器
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;
//注冊通知鍊
return cpufreq_register_notifier(&port->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
static inline void s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)
{//登出通知鍊
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
//在函數s3c24xx_serial_init_ports中被調用。建立各結構體的聯系，申請中斷，IO資源。複位端口
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;
//擷取cfg，該結構在檔案mach-tq2440中定義。在檔案S3C244x.c中有一個
//初始化函數 s3c244x_init_uarts，在該函數中調用函數s3c24xx_init_uartdevs
//在該函數中将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;
}
port->dev = &platdev->dev;//讓端口uart_port的成員dev指向平台裝置
//ourport的結構體類型為struct s3c24xx_uart_port不是uart_port。
//此處的info的結構體類型為s3c24xx_uart_info在檔案s3c2440.c 中定義，初始化。不是uart_info。
ourport->info = info;
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;
}
//擷取IO記憶體
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);
//在上面函數s3c24xx_serial_request_port中映射到虛拟位址
port->mapbase = res->start;
port->membase = S3C_VA_UART + res->start - (S3C_PA_UART & 0xfff00000);
//s3c2410_uart0_resource結構在檔案devs.c中定義，初始化。在該檔案中沒有中斷号為
//tx_irq的resource，隻有中斷号為rx_irq的resource，因為tx_irq = rx_irq + 1；
//是以platform_get_irq(platdev, 1);的傳回必然為空
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);//傳回空
if (ret > 0)
ourport->tx_irq = ret;
ourport->clk = clk_get(&platdev->dev, "uart");//擷取名為"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);
//調用函數info->reset_port複位序列槽，該函數在檔案s3c2440.c中實作
s3c24xx_serial_resetport(port, cfg);
return 0;
}
//屬性顯示
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);//裝置屬性
static int probe_index;//為端口在數組s3c24xx_serial_ports中的索引
//以下函數在檔案S3C2440.c中的函數s3c2440_serial_probe中調用
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);
//建立各結構體的聯系，申請中斷，IO資源。複位端口
ret = s3c24xx_serial_init_port(ourport, info, dev);
if (ret < 0)
goto probe_err;
dbg("%s: adding port\n", __func__);
//配置端口，構造與本端口對應的裝置節點
uart_add_one_port(&s3c24xx_uart_drv, &ourport->port);
platform_set_drvdata(dev, &ourport->port);//将ourport->port設為平台裝置的drvdata
ret = device_create_file(&dev->dev, &dev_attr_clock_source);//建立檔案屬性
if (ret < 0)
printk(KERN_ERR "%s: failed to add clksrc attr.\n", __func__);
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);
#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
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);
static int __init s3c24xx_serial_modinit(void)
{
int ret;
//注冊基于CPU s3c24xx的序列槽驅動，做各種重要的記憶體配置設定和結構的初始化
//本次注冊與硬體無關，不進行硬體的配置或是資源的擷取。
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);
#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) {
ufstat = rd_regl(port, S3C2410_UFSTAT);
return (ufstat & info->tx_fifofull) ? 0 : 1;
}
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();//發送器非空則等待發送結束
wr_regb(cons_uart, S3C2410_UTXH, ch);//寫一個數
}
//寫一個字元串
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);
}
//擷取端口的資料位數，校驗方式，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) {
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';
}
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);
}
}
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);
//s3c24xx_serial_console在下面初始化，co->index 初始化為-1，即是預設将第一個端口作為控制台
if (co->index == -1 || co->index >= CONFIG_SERIAL_SAMSUNG_UARTS)
co->index = 0;
//擷取整個驅動中作為控制台的那個端口
port = &s3c24xx_serial_ports[co->index].port;
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);
//擷取波特率，校驗方式，資料位，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);
//設定波特率，校驗方式，資料位，流控制
return uart_set_options(port, co, baud, parity, bits, flow);
}
//初始化控制台，在上面初始化結構體s3c24xx_uart_drv時，控制台結構将被挂到
//s3c24xx_uart_drv的cons成員上，在函數uart_add_one_port中将會讓端口結構體uart_port
//的成員cons指向該控制台結構體
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)
{//每個端口有一個對應的平台裝置對應，在檔案devs.c中初始化
struct platform_device *dev = s3c24xx_uart_devs[0];
dbg("s3c24xx_serial_initconsole\n");
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;
//将給予CPU 為s3c24xx的序列槽驅動挂到s3c24xx_serial_console.data上
s3c24xx_serial_console.data = &s3c24xx_uart_drv;
//初始化本驅動中的所有端口，
//建立與各個端口相關的各結構體間的聯系，申請中斷，IO資源。複位端口
s3c24xx_serial_init_ports(info);
//注冊控制台
register_console(&s3c24xx_serial_console);
return 0;
}
#endif
MODULE_DESCRIPTION("Samsung SoC Serial port driver");
MODULE_AUTHOR("Ben Dooks <[email protected]>");
MODULE_LICENSE("GPL v2");
![[轉]九大排序算法——C語言實作及詳解[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)