linux uart驱动——相关数据结构以及API(二)

一、核心数据结构
串口驱动有3个核心数据结构，它们都定义在<#include linux/serial_core.h>
1、uart_driver
uart_driver包含了串口设备名、串口驱动名、主次设备号、串口控制台(可选)等信息，还封装了tty_driver(底层串口驱动无需关心tty_driver)。

   1:  struct uart_driver {

   2:      struct module    *owner;      /* 拥有该uart_driver的模块,一般为THIS_MODULE */

   3:      const char    *driver_name; /* 串口驱动名，串口设备文件名以驱动名为基础 */

   4:      const char    *dev_name;      /* 串口设备名 */

   5:      int             major;          /* 主设备号 */

   6:      int             minor;          /* 次设备号 */

   7:      int             nr;          /* 该uart_driver支持的串口个数(最大) */

   8:      struct console    *cons;    /* 其对应的console.若该uart_driver支持serial console,否则为NULL */

9:

  10:      /*

  11:       * these are private; the low level driver should not

  12:       * touch these; they should be initialised to NULL

  13:       */

  14:      struct uart_state    *state;

  15:      struct tty_driver    *tty_driver;

  16:  };

2、uart_port
uart_port用于描述串口端口的I/O端口或I/O内存地址、FIFO大小、端口类型、串口时钟等信息。实际上，一个uart_port实例对应一个串口设备

   1:  struct uart_port {

   2:      spinlock_t        lock;            /* port lock 串口端口锁 */

   3:      unsigned long        iobase;        /* in/out[bwl] io端口基地 */

   4:      unsigned char __iomem    *membase;/* read/write[bwl] IO内存基地址,经映射(如ioremap)后的IO内存虚拟基地址 */

   5:      unsigned int        (*serial_in)(struct uart_port *, int);

   6:      void            (*serial_out)(struct uart_port *, int, int);

   7:      void            (*set_termios)(struct uart_port *,

   8:                                 struct ktermios *new,

   9:                                 struct ktermios *old);

  10:      void            (*pm)(struct uart_port *, unsigned int state,

  11:                        unsigned int old);

  12:      unsigned int        irq;            /* irq number */

  13:      unsigned long        irqflags;        /* irq flags  */

  14:      unsigned int        uartclk;        /* base uart clock */

  15:      unsigned int        fifosize;        /* tx fifo size */

  16:      unsigned char        x_char;            /* xon/xoff char */

  17:      unsigned char        regshift;        /* reg offset shift */

  18:      unsigned char        iotype;            /* io access style */

  19:      unsigned char        unused1;

20:

  21:  #define UPIO_PORT        (0)

  22:  #define UPIO_HUB6        (1)

  23:  #define UPIO_MEM        (2)

  24:  #define UPIO_MEM32        (3)

  25:  #define UPIO_AU            (4)            /* Au1x00 type IO */

  26:  #define UPIO_TSI        (5)            /* Tsi108/109 type IO */

  27:  #define UPIO_DWAPB        (6)            /* DesignWare APB UART */

  28:  #define UPIO_RM9000        (7)            /* RM9000 type IO */

  29:  #define UPIO_DWAPB32        (8)            /* DesignWare APB UART (32 bit accesses) */

30:

  31:      unsigned int        read_status_mask;    /* driver specific */

  32:      unsigned int        ignore_status_mask;    /* driver specific */

  33:      struct uart_state    *state;            /* pointer to parent state */

  34:      struct uart_icount    icount;            /* statistics */

35:

  36:      struct console        *cons;            /* struct console, if any */

  37:  #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)

  38:      unsigned long        sysrq;            /* sysrq timeout */

  39:  #endif

40:

  41:      upf_t            flags;

42:

  43:  #define UPF_FOURPORT        ((__force upf_t) (1 << 1))

  44:  #define UPF_SAK            ((__force upf_t) (1 << 2))

  45:  #define UPF_SPD_MASK        ((__force upf_t) (0x1030))

  46:  #define UPF_SPD_HI        ((__force upf_t) (0x0010))

  47:  #define UPF_SPD_VHI        ((__force upf_t) (0x0020))

  48:  #define UPF_SPD_CUST        ((__force upf_t) (0x0030))

  49:  #define UPF_SPD_SHI        ((__force upf_t) (0x1000))

  50:  #define UPF_SPD_WARP        ((__force upf_t) (0x1010))

  51:  #define UPF_SKIP_TEST        ((__force upf_t) (1 << 6))

  52:  #define UPF_AUTO_IRQ        ((__force upf_t) (1 << 7))

  53:  #define UPF_HARDPPS_CD        ((__force upf_t) (1 << 11))

  54:  #define UPF_LOW_LATENCY        ((__force upf_t) (1 << 13))

  55:  #define UPF_BUGGY_UART        ((__force upf_t) (1 << 14))

  56:  #define UPF_NO_TXEN_TEST    ((__force upf_t) (1 << 15))

  57:  #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) (1 << 16))

  58:  #define UPF_CONS_FLOW        ((__force upf_t) (1 << 23))

  59:  #define UPF_SHARE_IRQ        ((__force upf_t) (1 << 24))

  60:  /* The exact UART type is known and should not be probed.  */

  61:  #define UPF_FIXED_TYPE        ((__force upf_t) (1 << 27))

  62:  #define UPF_BOOT_AUTOCONF    ((__force upf_t) (1 << 28))

  63:  #define UPF_FIXED_PORT        ((__force upf_t) (1 << 29))

  64:  #define UPF_DEAD        ((__force upf_t) (1 << 30))

  65:  #define UPF_IOREMAP        ((__force upf_t) (1 << 31))

66:

  67:  #define UPF_CHANGE_MASK        ((__force upf_t) (0x17fff))

  68:  #define UPF_USR_MASK        ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))

69:

  70:      unsigned int        mctrl;            /* current modem ctrl settings */

  71:      unsigned int        timeout;        /* character-based timeout */

  72:      unsigned int        type;            /* port type */

  73:      const struct uart_ops    *ops;

  74:      unsigned int        custom_divisor;

  75:      unsigned int        line;            /* port index */

  76:      resource_size_t        mapbase;        /* for ioremap */

  77:      struct device        *dev;            /* parent device */

  78:      unsigned char        hub6;            /* this should be in the 8250 driver */

  79:      unsigned char        suspended;

  80:      unsigned char        irq_wake;

  81:      unsigned char        unused[2];

  82:      void            *private_data;        /* generic platform data pointer */

  83:  };.csharpcode,.csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff }
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uart_iconut为串口信息计数器，包含了发送字符计数、接收字符计数等。在串口的发送中断处理函数和接收中断处理函数中，我们需要管理这些计数。

   1:  struct uart_icount {

   2:      __u32    cts;

   3:      __u32    dsr;

   4:      __u32    rng;

   5:      __u32    dcd;

   6:      __u32    rx;      /* 发送字符计数 */

   7:      __u32    tx;      /* 接受字符计数 */

   8:      __u32    frame;   /* 帧错误计数 */

   9:      __u32    overrun; /* Rx FIFO溢出计数 */

  10:      __u32    parity;  /* 帧校验错误计数 */

  11:      __u32    brk;     /* break计数 */

  12:      __u32    buf_overrun;

  13:  };

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uart_stat有两个成员在底层串口驱动会用到：xmit和port。用户空间程序通过串口发送数据时，上层驱动将用户数据保存在xmit；而串口发送中断处理函数就是通过xmit获取到用户数据并将它们发送出去。串口接收中断处理函数需要通过port将接收到的数据传递给行规则层。

   1:  /*

   2:   * This is the state information which is persistent across opens.

   3:   */

   4:  struct uart_state {

   5:      struct tty_port        port;

6:

   7:      int            pm_state;

   8:      struct circ_buf        xmit;

9:

  10:      struct tasklet_struct    tlet;

  11:      struct uart_port    *uart_port;

  12:  };

3、uart_ops

uart_ops涵盖了串口驱动可对串口设备进行的所有操作

   1:  /*

   2:   * This structure describes all the operations that can be

   3:   * done on the physical hardware.

   4:   */

   5:  struct uart_ops {

   6:      unsigned int    (*tx_empty)(struct uart_port *);/* 串口的Tx FIFO缓存是否为空 */

   7:      void        (*set_mctrl)(struct uart_port *, unsigned int mctrl);/* 设置串口modem控制 */

   8:      unsigned int    (*get_mctrl)(struct uart_port *); /* 获取串口modem控制 */

   9:      void        (*stop_tx)(struct uart_port *);/* 禁止串口发送数据 */

  10:      void        (*start_tx)(struct uart_port *);/* 使能串口发送数据 */

  11:      void        (*send_xchar)(struct uart_port *, char ch);/* 发送xChar */

  12:      void        (*stop_rx)(struct uart_port *);/* 禁止串口接收数据 */

  13:      void        (*enable_ms)(struct uart_port *);/* 使能modem的状态信号 */

  14:      void        (*break_ctl)(struct uart_port *, int ctl); /* 设置break信号 */

  15:      int        (*startup)(struct uart_port *);/* 启动串口,应用程序打开串口设备文件时,该函数会被调用 */

  16:      void        (*shutdown)(struct uart_port *);/* 关闭串口,应用程序关闭串口设备文件时,该函数会被调用 */

  17:      void        (*flush_buffer)(struct uart_port *);

  18:      void        (*set_termios)(struct uart_port *, struct ktermios *new,

  19:                         struct ktermios *old);/* 设置串口参数 */

  20:      void        (*set_ldisc)(struct uart_port *, int new);

  21:      void        (*pm)(struct uart_port *, unsigned int state,

  22:                    unsigned int oldstate);/* 串口电源管理 */

  23:      int        (*set_wake)(struct uart_port *, unsigned int state);

  24:      void        (*wake_peer)(struct uart_port *);

25:

  26:      /*

  27:       * Return a string describing the type of the port

  28:       */

  29:      const char *(*type)(struct uart_port *);/* 返回一描述串口类型的字符串 */

30:

  31:      /*

  32:       * Release IO and memory resources used by the port.

  33:       * This includes iounmap if necessary.

  34:       */

  35:      void        (*release_port)(struct uart_port *);/* 释放串口已申请的IO端口/IO内存资源,必要时还需iounmap */

36:

  37:      /*

  38:       * Request IO and memory resources used by the port.

  39:       * This includes iomapping the port if necessary.

  40:       */

  41:      int        (*request_port)(struct uart_port *); /* 申请必要的IO端口/IO内存资源,必要时还可以重新映射串口端口 */

  42:      void        (*config_port)(struct uart_port *, int);/* 执行串口所需的自动配置 */

  43:      int        (*verify_port)(struct uart_port *, struct serial_struct *);/* 验证串口所需的自动配置 */

  44:      int        (*ioctl)(struct uart_port *, unsigned int, unsigned long);

  45:  #ifdef CONFIG_CONSOLE_POLL

  46:      void    (*poll_put_char)(struct uart_port *, unsigned char);

  47:      int        (*poll_get_char)(struct uart_port *);

  48:  #endif

  49:  };

二、串口驱动API

1、uart_register_driver

   1:  /  * 功能:uart_register_driver用于将串口驱动uart_driver注册到内核(串口核心层)中，通常在模块初始化函数调用该函数。

   2:     * 参数 drv：要注册的uart_driver

   3:     * 返回值：  成功，返回0；否则返回错误码

   4:  */

   5:    int uart_register_driver(struct uart_driver *drv)

2、uart_unregister_driver

   1:  /* 功能：    uart_unregister_driver用于注销我们已注册的uart_driver，通常在模块卸载函数调用该函数

   2:   * 参数 drv：要注销的uart_driver

3:

   4:   * 返回值：  成功，返回0；否则返回错误码

   5:   */

   6:  void uart_unregister_driver(struct uart_driver *drv)

7:

3、uart_add_one_port

   1:  /* 功能：    uart_add_one_port用于为串口驱动添加一个串口端口，通常在探测到设备后(驱动的设备probe方法)调用该函数

   2:   * 参数 drv：串口驱动

   3:   *      port:要添加的串口端口

4:

   5:   * 返回值：  成功，返回0；否则返回错误码

   6:   */

   7:  int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)

4、uart_remove_one_port

   1:  /* 功能：     uart_remove_one_port用于删除一个已添加到串口驱动中的串口端口，通常在驱动卸载时调用该函数

   2:   * 参数 drv： 串口驱动

   3:   *      port: 要删除的串口端口

   4:   * 返回值：   成功，返回0；否则返回错误码

   5:   */

   6:  int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)

5、uart_write_wakeup

   1:  /* 功能：     uart_write_wakeup唤醒上层因向串口端口写数据而阻塞的进程，通常在串口发送中断处理函数中调用该函数

   2:   * 参数 port：需要唤醒写阻塞进程的串口端口

   3:   */

   4:  void uart_write_wakeup(struct uart_port *port)

6、uart_suspend_port

   1:  /* 功能：     uart_suspend_port用于挂起特定的串口端口

   2:   * 参数 drv： 要挂起的串口端口所属的串口驱动

   3:   *      port：要挂起的串口端口

   4:   * 返回值：   成功返回0；否则返回错误码

   5:   */

   6:  int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)

7、uart_resume_port

   1:  /* 功能：     uart_resume_port用于恢复某一已挂起的串口

   2:   * 参数 drv： 要恢复的串口端口所属的串口驱动

   3:   *      port：要恢复的串口端口

   4:   * 返回值：   成功返回0；否则返回错误码

   5:   */

   6:  int uart_resume_port(struct uart_driver *drv, struct uart_port *port)

8、uart_get_baud_rate

   1:  /* 功能：        uart_get_baud_rate通过解码termios结构体来获取指定串口的波特率

   2:   * 参数 port：  要获取波特率的串口端口

   3:   *     termios：当前期望的termios配置(包含串口波特率)

   4:   *     old：    以前的termios配置，可以为NULL

   5:   *     min：    可接受的最小波特率

   6:   *     max：    可接受的最大波特率

   7:   * 返回值：     串口的波特率

   8:   */

   9:  unsigned int

  10:  uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,

  11:  struct ktermios *old, unsigned int min, unsigned int max)

9、uart_get_divisor

   1:  /* 功能：     uart_get_divisor用于计算某一波特率的串口时钟分频数（串口波特率除数）

   2:   * 参数 port：要计算时钟分频数的串口端口

   3:   *      baud：期望的波特率

   4:   *返回值：    串口时钟分频数

   5:   */

   6:  unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud)

10、uart_update_timeout

   1:  /* 功能：      uart_update_timeout用于更新（设置）串口FIFO超时时间

   2:   * 参数 port： 要更新超时时间的串口端口

   3:   *     cflag：termios结构体的cflag值

   4:   *     baud： 串口的波特率

   5:   */

   6:  void uart_update_timeout(struct uart_port *port, unsigned int cflag, unsigned int baud)

11、uart_match_port

   1:  /* 功能：uart_match_port用于判断两串口端口是否为同一端口

   2:   * 参数 port1、port2：要判断的串口端口

   3:   * 返回值：不同返回0；否则返回非0

   4:   */

   5:  int uart_match_port(struct uart_port *port1, struct uart_port *port2)

12、uart_console_write

   1:  /* 功能：        uart_console_write用于向串口端口写一控制台信息

2:

   3:   * 参数 port:    要写信息的串口端口

   4:   *     s:       要写的信息

   5:   *     count:   信息的大小

   6:   *     putchar: 用于向串口端口写字符的函数，该函数函数有两个参数：串口端口和要写的字符

   7:   */

   8:  void uart_console_write(struct uart_port *port, const char *s,

   9:  unsigned int count,

  10:  void (*putchar)(struct uart_port *, int))

11:

时间： 2024-10-14 13:46:03

linux uart驱动——相关数据结构以及API(二)

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