tty 驱动学习

9710阅读　0评论2020-02-22　fangdikui
分类：LINUX

Makefile

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  1. KBUILD_EXTRA_SYMBOLS=/home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-3.2.0-psp04.06.00.11/am335x_evm/Module.symvers
  2. ifneq ($(KERNELRELEASE),)
  3.     obj-m := my_tty.o
  4. else
  5.     KERNELDIR ?= /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-3.2.0-psp04.06.00.11/am335x_evm
  6.     PWD := $(shell pwd)
  7. default:
  8.     $(MAKE) -C $(KERNELDIR) M=$(PWD) modules
  9.     cp *.ko /home/fang/ti-sdk-am335x-evm-06.00.00.00/filesystem/rootfs/test_modules
  10. clean:
  11.     @rm -rf *.o *.mod.c *.mod.o *.ko *.order *.symvers .*.cmd .tmp_versions
  12. endif


my_tty.c

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  1. #include <linux/module.h>
  2. #include <linux/types.h>
  3. #include <linux/sched.h>
  4. #include <linux/tty.h>
  5. #include <linux/tty_flip.h>
  6. #include <linux/kernel.h>
  7. #include <linux/string.h>
  8. #include <linux/errno.h>
  9. #include <linux/kd.h>
  10. #include <linux/slab.h>
  11. #include <linux/major.h>
  12. #include <linux/mm.h>
  13. #include <linux/console.h>
  14. #include <linux/init.h>
  15. #include <linux/mutex.h>
  16. #include <linux/vt_kern.h>
  17. #include <linux/selection.h>
  18. #include <linux/tiocl.h>
  19. #include <linux/kbd_kern.h>
  20. #include <linux/consolemap.h>
  21. #include <linux/timer.h>
  22. #include <linux/interrupt.h>
  23. #include <linux/workqueue.h>
  24. #include <linux/pm.h>
  25. #include <linux/font.h>
  26. #include <linux/bitops.h>
  27. #include <linux/notifier.h>
  28. #include <linux/device.h>
  29. #include <linux/io.h>
  30. #include <asm/system.h>
  31. #include <linux/uaccess.h>
  32. #include <linux/kdb.h>
  33. #include <linux/ctype.h>

  35. static int con_open(struct tty_struct *, struct file *);
  36. static void vc_init(struct vc_data *vc, unsigned int rows,
  37.          unsigned int cols, int do_clear);
  38. static void gotoxy(struct vc_data *vc, int new_x, int new_y);
  39. static void save_cur(struct vc_data *vc);
  40. static void reset_terminal(struct vc_data *vc, int do_clear);
  41. static void con_flush_chars(struct tty_struct *tty);
  42. static int set_vesa_blanking(char __user *p);
  43. static void set_cursor(struct vc_data *vc);
  44. static void hide_cursor(struct vc_data *vc);
  45. static void console_callback(struct work_struct *ignored);
  46. static void blank_screen_t(unsigned long dummy);
  47. static void set_palette(struct vc_data *vc);


  50. struct tty_driver *console_driver;

  52. /*
  53.  * /dev/ttyN handling
  54.  */

  56. static int con_write(struct tty_struct *tty, const unsigned char *buf, int count)
  57. {
  58.     int    retval;
  59.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  60.     return count;
  61. }

  63. static int con_put_char(struct tty_struct *tty, unsigned char ch)
  64. {
  65.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  66.     return 0;
  67. }

  69. static int con_chars_in_buffer(struct tty_struct *tty)
  70. {
  71.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  72.     return 0;        /* we're not buffering */
  73. }

  75. /*
  76.  * con_throttle and con_unthrottle are only used for
  77.  * paste_selection(), which has to stuff in a large number of
  78.  * characters...
  79.  */
  80. static void con_throttle(struct tty_struct *tty)
  81. {
  82.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  83. }

  85. static void con_unthrottle(struct tty_struct *tty)
  86. {
  87.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  88. }

  90. /*
  91.  * Allocate the console screen memory.
  92.  */
  93. static int con_open(struct tty_struct *tty, struct file *filp)
  94. {
  95.     unsigned int currcons = tty->index;
  96.     int ret = 0;
  97.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  98.     console_lock();
  99.     console_unlock();
  100.     return ret;
  101. }

  103. static void con_close(struct tty_struct *tty, struct file *filp)
  104. {
  105.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  106.     /* Nothing to do - we defer to shutdown */
  107. }

  109. static void con_shutdown(struct tty_struct *tty)
  110. {
  111.     struct vc_data *vc = tty->driver_data;
  112.     //BUG_ON(vc == NULL);
  113.     console_lock();
  114.     //vc->port.tty = NULL;
  115.     console_unlock();
  116.     tty_shutdown(tty);
  117. }
  118. static int con_write_room(struct tty_struct *tty)
  119. {
  120.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  121.     if (tty->stopped)
  122.         return 0;
  123.     return 32768;        /* No limit, really; we're not buffering */
  124. }
  125. static void con_stop(struct tty_struct *tty)
  126. {
  127.     int console_num;
  128.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  129.     
  130. }
  131. /*
  132.  * Turn the Scroll-Lock LED off when the console is started
  133.  */
  134. static void con_start(struct tty_struct *tty)
  135. {
  136.     int console_num;
  137.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  138. }

  140. static int vt_resize(struct tty_struct *tty, struct winsize *ws)
  141. {
  142.     struct vc_data *vc = tty->driver_data;
  143.     int ret;

  145.     console_lock();
  146.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  147.     console_unlock();
  148.     return 0;
  149. }
  150. static void con_flush_chars(struct tty_struct *tty)
  151. {
  152.     printk(" %s %s line:%d\n", __func__,__FILE__,__LINE__);
  153. }




  158. /*
  159.  * We handle the console-specific ioctl's here. We allow the
  160.  * capability to modify any console, not just the fg_console.
  161.  */
  162. int vt_ioctl(struct tty_struct *tty,
  163.      unsigned int cmd, unsigned long arg)
  164. {
  165.     return 0;
  166. }

  168. static const struct tty_operations con_ops = {
  169.     .open = con_open,
  170.     .close = con_close,
  171.     .write = con_write,
  172.     .write_room = con_write_room,
  173.     .put_char = con_put_char,
  174.     .flush_chars = con_flush_chars,
  175.     .chars_in_buffer = con_chars_in_buffer,
  176.     .ioctl = vt_ioctl,
  177. #ifdef CONFIG_COMPAT
  178.     .compat_ioctl = vt_compat_ioctl,
  179. #endif
  180.     .stop = con_stop,
  181.     .start = con_start,
  182.     .throttle = con_throttle,
  183.     .unthrottle = con_unthrottle,
  184.     .resize = vt_resize,
  185.     .shutdown = con_shutdown
  186. };

  188. static struct cdev vc0_cdev;
  189. int default_utf8 = true;
  190. int __init mytty_init(const struct file_operations *console_fops)
  191. {
  192.     console_driver = alloc_tty_driver(MAX_NR_CONSOLES);
  193.     if (!console_driver)
  194.         panic("Couldn't allocate console driver\n");
  195.     console_driver->owner = THIS_MODULE;
  196.     console_driver->name = "tty_my";
  197.     console_driver->name_base = 1;
  198.     console_driver->major = TTY_MAJOR;
  199.     console_driver->minor_start = 128;
  200.     console_driver->type = TTY_DRIVER_TYPE_CONSOLE;
  201.     console_driver->init_termios = tty_std_termios;
  202.     if (default_utf8)
  203.         console_driver->init_termios.c_iflag |= IUTF8;
  204.     console_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
  205.     tty_set_operations(console_driver, &con_ops);
  206.     printk("console_driver ->num:%08x %s %s line:%d\n", console_driver->num,__func__,__FILE__,__LINE__);
  207.     if (tty_register_driver(console_driver))
  208.         panic("Couldn't register console driver\n");

  210.     return 0;
  211. }
  212. static void mytty_exit(void)
  213. {
  214.     int i = 0;
  215.     tty_unregister_driver(console_driver);
  216.     for (i=0; i <console_driver->num; i++)
  217.         tty_unregister_device(console_driver, i);
  218. }

  220. module_init(mytty_init);
  221. module_exit(mytty_exit);

  223. MODULE_LICENSE("GPL");
测试：

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  1. insmod my_tty.ko
  2. echo a>/dev/tty_my1
  3. [ 165.343902] con_open /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-modules/3.2.0/ttydriver/my_tty.c line:99
  4. [ 165.355804] con_write_room /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-modules/3.2.0/ttydriver/my_tty.c line:122
  5. [ 165.368194] con_write /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-modules/3.2.0/ttydriver/my_tty.c line:61
  6. [ 165.380035] con_write_room /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-modules/3.2.0/ttydriver/my_tty.c line:122
  7. [ 165.392395] con_write /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-modules/3.2.0/ttydriver/my_tty.c line:61
  8. [ 165.404235] con_flush_chars /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-modules/3.2.0/ttydriver/my_tty.c line:154
  9. [ 165.416748] con_close /home/fang/ti-sdk-am335x-evm-06.00.00.00/board-support/linux-modules/3.2.0/ttydriver/my_tty.c line:107


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