#include <linux/module.h> #include <linux/init.h> #include <linux/kernel.h> /* printk() */ #include <linux/slab.h> /* kmalloc() */ #include <linux/fs.h> /* everything... */ #include <linux/errno.h> /* error codes */ #include <linux/types.h> /* size_t */ #include <linux/fcntl.h> /* O_ACCMODE */ #include <asm/system.h> /* cli(), *_flags */ #include <asm/uaccess.h> /* copy_*_user */ #include <linux/ioctl.h> #include <linux/device.h>
#include <linux/platform_device.h> #include <linux/sysrq.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/console.h> #include <asm/io.h> #include <asm/irq.h> #include <asm/hardware.h> #include <asm/plat-s3c/regs-serial.h> #include <asm/arch/regs-gpio.h>
#define DEV_NAME "gprs_uart" /* 设备名 */ /* 这里将串口的主设备号设为0,则串口设备编号由内核动态分配;你也可指定串口的设备编号 */ #define GPRS_UART_MAJOR 0 /* 主设备号 */ #define GPRS_UART_MINOR 0 /* 次设备号 */ #define GPRS_UART_FIFO_SIZE 16 /* 串口FIFO的大小 */ #define RXSTAT_DUMMY_READ (0x10000000) #define MAP_SIZE (0x100) /* 要映射的串口IO内存区大小 */
/* 串口发送中断号 */ #define TX_IRQ(port) ((port)->irq + 1) /* 串口接收中断号 */ #define RX_IRQ(port) ((port)->irq)
/* 允许串口接收字符的标志 */ #define tx_enabled(port) ((port)->unused[0]) /* 允许串口发送字符的标志 */ #define rx_enabled(port) ((port)->unused[1])
/* 获取寄存器地址 */ #define portaddr(port, reg) ((port)->membase + (reg))
/* 读8位宽的寄存器 */ #define rd_regb(port, reg) (ioread8(portaddr(port, reg))) /* 读32位宽的寄存器 */ #define rd_regl(port, reg) (ioread32(portaddr(port, reg))) /* 写8位宽的寄存器 */ #define wr_regb(port, reg, val) \ do { iowrite8(val, portaddr(port, reg)); } while(0) /* 写32位宽的寄存器 */ #define wr_regl(port, reg, val) \ do { iowrite32(val, portaddr(port, reg)); } while(0)
/* 禁止串口发送数据 */ static void gprs_uart_stop_tx(struct uart_port *port) { if (tx_enabled(port)) /* 若串口已启动发送 */ { disable_irq(TX_IRQ(port)); /* 禁止发送中断 */ tx_enabled(port) = 0; /* 设置串口为未启动发送 */ } }
/* 使能串口发送数据 */ static void gprs_uart_start_tx(struct uart_port *port) { if (!tx_enabled(port)) /* 若串口未启动发送 */ { enable_irq(TX_IRQ(port)); /* 使能发送中断 */ tx_enabled(port) = 1; /* 设置串口为已启动发送 */ } }
/* 禁止串口接收数据 */ static void gprs_uart_stop_rx(struct uart_port *port) { if (rx_enabled(port)) /* 若串口已启动接收 */ { disable_irq(RX_IRQ(port)); /* 禁止接收中断 */ rx_enabled(port) = 0; /* 设置串口为未启动接收 */ } }
/* 使能modem的状态信号 */ static void gprs_uart_enable_ms(struct uart_port *port) { }
/* 串口的Tx FIFO缓存是否为空 */ static unsigned int gprs_uart_tx_empty(struct uart_port *port) { int ret = 1; unsigned long ufstat = rd_regl(port, S3C2410_UFSTAT); unsigned long ufcon = rd_regl(port, S3C2410_UFCON);
if (ufcon & S3C2410_UFCON_FIFOMODE) /* 若使能了FIFO */ { if ((ufstat & S3C2410_UFSTAT_TXMASK) != 0 || /* 0 (ufstat & S3C2410_UFSTAT_TXFULL)) /* FIFO满 */ ret = 0; } else /* 若未使能了FIFO,则判断发送缓存和发送移位寄存器是否均为空 */ { ret = rd_regl(port, S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXE; } return ret; }
/* 获取串口modem控制,因为uart2无modem控制,所以CTS、DSR直接返回有效 */ static unsigned int gprs_uart_get_mctrl(struct uart_port *port) { return (TIOCM_CTS | TIOCM_DSR | TIOCM_CAR); }
/* 设置串口modem控制 */ static void gprs_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) {
}
/* 设置break信号 */ static void gprs_uart_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; else ucon &= ~S3C2410_UCON_SBREAK;
wr_regl(port, S3C2410_UCON, ucon);
spin_unlock_irqrestore(&port->lock, flags); }
/* 返回Rx FIFO已存多少数据 */ static int gprs_uart_rx_fifocnt(unsigned long ufstat) { /* 若Rx FIFO已满,返回FIFO的大小 */ if (ufstat & S3C2410_UFSTAT_RXFULL) return GPRS_UART_FIFO_SIZE;
/* 若FIFO未满,返回Rx FIFO已存了多少字节数据 */ return (ufstat & S3C2410_UFSTAT_RXMASK) >> S3C2410_UFSTAT_RXSHIFT; }
#define S3C2410_UERSTAT_PARITY (0x1000)
/* 串口接收中断处理函数,获取串口接收到的数据,并将这些数据递交给行规则层 */ static irqreturn_t gprs_uart_rx_chars(int irq, void *dev_id) { struct uart_port *port = dev_id; struct tty_struct *tty = port->info->tty; unsigned int ufcon, ch, flag, ufstat, uerstat; int max_count = 64;
/* 循环接收数据,最多一次中断接收64字节数据 */ while (max_count-- > 0) { ufcon = rd_regl(port, S3C2410_UFCON); ufstat = rd_regl(port, S3C2410_UFSTAT);
/* 若Rx FIFO无数据了,跳出循环 */ if (gprs_uart_rx_fifocnt(ufstat) == 0) break;
/* 读取Rx error状态寄存器 */ uerstat = rd_regl(port, S3C2410_UERSTAT); /* 读取已接受到的数据 */ ch = rd_regb(port, S3C2410_URXH);
/* insert the character into the buffer */ /* 先将tty标志设为正常 */ flag = TTY_NORMAL; /* 递增接收字符计数器 */ port->icount.rx++;
/* 判断是否存在Rx error * if (unlikely(uerstat & S3C2410_UERSTAT_ANY))等同于 * if (uerstat & S3C2410_UERSTAT_ANY) * 只是unlikely表示uerstat & S3C2410_UERSTAT_ANY的值为假的可能性大一些 * 另外还有一个likely(value)表示value的值为真的可能性更大一些 */ if (unlikely(uerstat & S3C2410_UERSTAT_ANY)) { /* 若break错误,递增icount.brk计算器 */ if (uerstat & S3C2410_UERSTAT_BREAK) { port->icount.brk++; if (uart_handle_break(port)) goto ignore_char; }
/* 若frame错误,递增icount.frame计算器 */ if (uerstat & S3C2410_UERSTAT_FRAME) port->icount.frame++; /* 若overrun错误,递增icount.overrun计算器 */ if (uerstat & S3C2410_UERSTAT_OVERRUN) port->icount.overrun++;
/* 查看我们是否关心该Rx error * port->read_status_mask保存着我们感兴趣的Rx error status */ uerstat &= port->read_status_mask;
/* 若我们关心该Rx error,则将flag设置为对应的error flag */ 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; }
/* 处理sys字符 */ if (uart_handle_sysrq_char(port, ch)) goto ignore_char;
/* 将接收到的字符插入到tty设备的flip缓冲 */ uart_insert_char(port, uerstat, S3C2410_UERSTAT_OVERRUN, ch, flag);
ignore_char: continue; } /* 刷新tty设备的flip缓冲,将接受到的数据传给行规则层 */ tty_flip_buffer_push(tty);
return IRQ_HANDLED; }
/* 串口发送中断处理函数,将用户空间的数据(保存在环形缓冲xmit里)发送出去 */ static irqreturn_t gprs_uart_tx_chars(int irq, void *dev_id) { struct uart_port *port = dev_id; struct circ_buf *xmit = &port->info->xmit; /* 获取环线缓冲 */ int count = 256;
/* 若设置了xChar字符 */ if (port->x_char) { /* 将该xChar发送出去 */ wr_regb(port, S3C2410_UTXH, port->x_char); /* 递增发送计数 */ port->icount.tx++; /* 清除xChar */ port->x_char = 0; /* 退出中断处理 */ goto out; }
/* 如果没有更多的字符需要发送(环形缓冲为空), * 或者uart Tx已停止, * 则停止uart并退出中断处理函数 */ if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { gprs_uart_stop_tx(port); goto out; }
/* 循环发送数据,直到环形缓冲为空,最多一次中断发送256字节数据 */ while (!uart_circ_empty(xmit) && count-- > 0) { /* 若Tx FIFO已满,退出循环 */ if (rd_regl(port, S3C2410_UFSTAT) & S3C2410_UFSTAT_TXFULL) break;
/* 将要发送的数据写入Tx FIFO */ wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]); /* 移向循环缓冲中下一要发送的数据 */ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; }
/* 如果环形缓冲区中剩余的字符少于WAKEUP_CHARS,唤醒上层 */ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port);
/* 如果环形缓冲为空,则停止发送 */ if (uart_circ_empty(xmit)) gprs_uart_stop_tx(port);
out: return IRQ_HANDLED; }
/* 启动串口端口,在打开该驱动的设备文件时会调用该函数来申请串口中断,并设置串口为可接受,也可发送 */ static int gprs_uart_startup(struct uart_port *port) { unsigned long flags; int ret; const char *portname = to_platform_device(port->dev)->name;
/* 设置串口为不可接受,也不可发送 */ rx_enabled(port) = 0; tx_enabled(port) = 0;
spin_lock_irqsave(&port->lock, flags);
/* 申请接收中断 */ ret = request_irq(RX_IRQ(port), gprs_uart_rx_chars, 0, portname, port); if (ret != 0) { printk(KERN_ERR "cannot get irq %d\n", RX_IRQ(port)); return ret; }
/* 设置串口为允许接收 */ rx_enabled(port) = 1;
/* 申请发送中断 */ ret = request_irq(TX_IRQ(port), gprs_uart_tx_chars, 0, portname, port); if (ret) { printk(KERN_ERR "cannot get irq %d\n", TX_IRQ(port)); rx_enabled(port) = 0; free_irq(RX_IRQ(port), port); goto err; } /* 设置串口为允许发送 */ tx_enabled(port) = 1;
err: spin_unlock_irqrestore(&port->lock, flags); return ret; }
/* 关闭串口,在关闭驱动的设备文件时会调用该函数,释放串口中断 */ static void gprs_uart_shutdown(struct uart_port *port) { rx_enabled(port) = 0; /* 设置串口为不允许接收 */ free_irq(RX_IRQ(port), port); /* 释放接收中断 */ tx_enabled(port) = 0; /* 设置串口为不允许发送 */ free_irq(TX_IRQ(port), port); /* 释放发送中断 */ }
/* 设置串口参数 */ static void gprs_uart_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { unsigned long flags; unsigned int baud, quot; unsigned int ulcon, ufcon = 0;
/* 不支持moden控制信号线 * HUPCL: 关闭时挂断moden * CMSPAR: mark or space (stick) parity * CLOCAL: 忽略任何moden控制线 */ termios->c_cflag &= ~(HUPCL | CMSPAR); termios->c_cflag |= CLOCAL;
/* 获取用户设置的串口波特率,并计算分频数(串口波特率除数quot) */ 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 = port->uartclk / baud / 16 - 1;
/* 设置数据字长 */ switch (termios->c_cflag & CSIZE) { case CS5: ulcon = S3C2410_LCON_CS5; break; case CS6: ulcon = S3C2410_LCON_CS6; break; case CS7: ulcon = S3C2410_LCON_CS7; break; case CS8: default: ulcon = S3C2410_LCON_CS8; break; }
/* 是否要求设置两个停止位(CSTOPB) */ if (termios->c_cflag & CSTOPB) ulcon |= S3C2410_LCON_STOPB;
/* 是否使用奇偶检验 */ if (termios->c_cflag & PARENB) { if (termios->c_cflag & PARODD) /* 奇校验 */ ulcon |= S3C2410_LCON_PODD; else /* 偶校验 */ ulcon |= S3C2410_LCON_PEVEN; } else /* 无校验 */ { ulcon |= S3C2410_LCON_PNONE; }
if (port->fifosize > 1) ufcon |= S3C2410_UFCON_FIFOMODE | S3C2410_UFCON_RXTRIG8;
spin_lock_irqsave(&port->lock, flags);
/* 设置FIFO控制寄存器、线控制寄存器和波特率除数寄存器 */ wr_regl(port, S3C2410_UFCON, ufcon); wr_regl(port, S3C2410_ULCON, ulcon); wr_regl(port, S3C2410_UBRDIV, quot);
/* 更新串口FIFO的超时时限 */ uart_update_timeout(port, termios->c_cflag, baud);
/* 设置我们感兴趣的Rx error */ port->read_status_mask = S3C2410_UERSTAT_OVERRUN; if (termios->c_iflag & INPCK) port->read_status_mask |= S3C2410_UERSTAT_FRAME | S3C2410_UERSTAT_PARITY;
/* 设置我们忽略的Rx error */ 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;
/* 若未设置CREAD(使用接收器),则忽略所有Rx error*/ if ((termios->c_cflag & CREAD) == 0) port->ignore_status_mask |= RXSTAT_DUMMY_READ;
spin_unlock_irqrestore(&port->lock, flags); }
/* 获取串口类型 */ static const char *gprs_uart_type(struct uart_port *port) {/* 返回描述串口类型的字符串指针 */ return port->type == PORT_S3C2410 ? "gprs_uart:s3c2410_uart2" : NULL; }
/* 申请串口一些必要的资源,如IO端口/IO内存资源,必要时还可以重新映射串口端口 */ static int gprs_uart_request_port(struct uart_port *port) { struct resource *res; const char *name = to_platform_device(port->dev)->name;
/* request_mem_region请求分配IO内存,从开始port->mapbase,大小MAP_SIZE * port->mapbase保存当前串口的寄存器基地址(物理) * uart2: 0x50008000 */ res = request_mem_region(port->mapbase, MAP_SIZE, name); if (res == NULL) { printk(KERN_ERR"request_mem_region error: %p\n", res); return -EBUSY; } return 0; }
/* 释放串口已申请的IO端口/IO内存资源,必要时还需iounmap */ static void gprs_uart_release_port(struct uart_port *port) { /* 释放已分配IO内存 */ release_mem_region(port->mapbase, MAP_SIZE); }
/* 执行串口所需的自动配置 */ static void gprs_uart_config_port(struct uart_port *port, int flags) { int retval;
/* 请求串口 */ retval = gprs_uart_request_port(port); /* 设置串口类型 */ if (flags & UART_CONFIG_TYPE && retval == 0) port->type = PORT_S3C2410; }
/* The UART operations structure */ static struct uart_ops gprs_uart_ops = { .start_tx = gprs_uart_start_tx, /* Start transmitting */ .stop_tx = gprs_uart_stop_tx, /* Stop transmission */ .stop_rx = gprs_uart_stop_rx, /* Stop reception */ .enable_ms = gprs_uart_enable_ms, /* Enable modem status signals */ .tx_empty = gprs_uart_tx_empty, /* Transmitter busy? */ .get_mctrl = gprs_uart_get_mctrl, /* Get modem control */ .set_mctrl = gprs_uart_set_mctrl, /* Set modem control */ .break_ctl = gprs_uart_break_ctl, /* Set break signal */ .startup = gprs_uart_startup, /* App opens GPRS_UART */ .shutdown = gprs_uart_shutdown, /* App closes GPRS_UART */ .set_termios = gprs_uart_set_termios, /* Set termios */ .type = gprs_uart_type, /* Get UART type */ .request_port = gprs_uart_request_port, /* Claim resources associated with a GPRS_UART port */ .release_port = gprs_uart_release_port, /* Release resources associated with a GPRS_UART port */ .config_port = gprs_uart_config_port, /* Configure when driver adds a GPRS_UART port */ };
/* Uart driver for GPRS_UART */ static struct uart_driver gprs_uart_driver = { .owner = THIS_MODULE, /* Owner */ .driver_name = DEV_NAME, /* Driver name */ .dev_name = DEV_NAME, /* Device node name */ .major = GPRS_UART_MAJOR, /* Major number */ .minor = GPRS_UART_MINOR, /* Minor number start */ .nr = 1, /* Number of UART ports */ };
/* Uart port for GPRS_UART port */ static struct uart_port gprs_uart_port = { .irq = IRQ_S3CUART_RX2, /* IRQ */ .fifosize = GPRS_UART_FIFO_SIZE, /* Size of the FIFO */ .iotype = UPIO_MEM, /* IO memory */ .flags = UPF_BOOT_AUTOCONF, /* UART port flag */ .ops = &gprs_uart_ops, /* UART operations */ .line = 0, /* UART port number */ .lock = __SPIN_LOCK_UNLOCKED(gprs_uart_port.lock), };
/* 初始化指定串口端口 */ static int gprs_uart_init_port(struct uart_port *port, struct platform_device *platdev) { unsigned long flags; unsigned int gphcon; if (platdev == NULL) return -ENODEV;
port->dev = &platdev->dev;
/* 设置串口波特率时钟频率 */ port->uartclk = clk_get_rate(clk_get(&platdev->dev, "pclk"));
/* 设置串口的寄存器基地址(物理): 0x50008000 */ port->mapbase = S3C2410_PA_UART2; /* 设置当前串口的寄存器基地址(虚拟): 0xF5008000 */ port->membase = S3C24XX_VA_UART + (S3C2410_PA_UART2 - S3C24XX_PA_UART);
spin_lock_irqsave(&port->lock, flags);
wr_regl(port, S3C2410_UCON, S3C2410_UCON_DEFAULT); wr_regl(port, S3C2410_ULCON, S3C2410_LCON_CS8 | S3C2410_LCON_PNONE); wr_regl(port, S3C2410_UFCON, S3C2410_UFCON_FIFOMODE | S3C2410_UFCON_RXTRIG8 | S3C2410_UFCON_RESETBOTH);
/* 将I/O port H的gph6和gph7设置为TXD2和RXD2 */ gphcon = readl(S3C2410_GPHCON); gphcon &= ~((0x5) << 12); writel(gphcon, S3C2410_GPHCON); spin_unlock_irqrestore(&port->lock, flags); return 0; }
/* Platform driver probe */ static int __init gprs_uart_probe(struct platform_device *dev) { int ret; /* 初始化串口 */ ret = gprs_uart_init_port(&gprs_uart_port, dev); if (ret < 0) { printk(KERN_ERR"gprs_uart_probe: gprs_uart_init_port error: %d\n", ret); return ret; }
/* 添加串口 */ ret = uart_add_one_port(&gprs_uart_driver, &gprs_uart_port); if (ret < 0) { printk(KERN_ERR"gprs_uart_probe: uart_add_one_port error: %d\n", ret); return ret; }
/* 将串口uart_port结构体保存在platform_device->dev->driver_data中 */ platform_set_drvdata(dev, &gprs_uart_port);
return 0; }
/* Called when the platform driver is unregistered */ static int gprs_uart_remove(struct platform_device *dev) { platform_set_drvdata(dev, NULL);
/* 移除串口 */ uart_remove_one_port(&gprs_uart_driver, &gprs_uart_port); return 0; }
/* Suspend power management event */ static int gprs_uart_suspend(struct platform_device *dev, pm_message_t state) { uart_suspend_port(&gprs_uart_driver, &gprs_uart_port); return 0; }
/* Resume after a previous suspend */ static int gprs_uart_resume(struct platform_device *dev) { uart_resume_port(&gprs_uart_driver, &gprs_uart_port); return 0; }
/* Platform driver for GPRS_UART */ static struct platform_driver gprs_plat_driver = { .probe = gprs_uart_probe, /* Probe method */ .remove = __exit_p(gprs_uart_remove), /* Detach method */ .suspend = gprs_uart_suspend, /* Power suspend */ .resume = gprs_uart_resume, /* Resume after a suspend */ .driver = { .owner = THIS_MODULE, .name = DEV_NAME, /* Driver name */ }, };
/* Platform device for GPRS_UART */ struct platform_device *gprs_plat_device;
static int __init gprs_init_module(void) { int retval;
/* Register uart_driver for GPRS_UART */ retval = uart_register_driver(&gprs_uart_driver); if (0 != retval) { printk(KERN_ERR "gprs_init_module: can't register the GPRS_UART driver %d\n", retval); return retval; }
/* Register platform device for GPRS_UART. Usually called during architecture-specific setup */ gprs_plat_device = platform_device_register_simple(DEV_NAME, 0, NULL, 0); if (IS_ERR(gprs_plat_device)) { retval = PTR_ERR(gprs_plat_device); printk(KERN_ERR "gprs_init_module: can't register platform device %d\n", retval); goto fail_reg_plat_dev; }
/* Announce a matching driver for the platform devices registered above */ retval = platform_driver_register(&gprs_plat_driver); if (0 != retval) { printk(KERN_ERR "gprs_init_module: can't register platform driver %d\n", retval); goto fail_reg_plat_drv; }
return 0; /* succeed */
fail_reg_plat_drv: platform_device_unregister(gprs_plat_device); fail_reg_plat_dev: uart_unregister_driver(&gprs_uart_driver); return retval; }
static void __exit gprs_exit_module(void) { /* The order of unregistration is important. Unregistering the UART driver before the platform driver will crash the system */
/* Unregister the platform driver */ platform_driver_unregister(&gprs_plat_driver);
/* Unregister the platform devices */ platform_device_unregister(gprs_plat_device);
/* Unregister the GPRS_UART driver */ uart_unregister_driver(&gprs_uart_driver); }
module_init(gprs_init_module); module_exit(gprs_exit_module);
MODULE_AUTHOR("lingd"); MODULE_LICENSE("Dual BSD/GPL");
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