/* * Telephony registration for Linux * * (c) Copyright 1999 Red Hat Software Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Author: Alan Cox, <alan@redhat.com> * * Fixes: Mar 01 2000 Thomas Sparr, <thomas.l.sparr@telia.com> * phone_register_device now works with unit!=PHONE_UNIT_ANY */ #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/string.h> #include <linux/errno.h> #include <linux/phonedev.h> #include <linux/init.h> #include <asm/uaccess.h> #include <asm/system.h> #include <linux/kmod.h> #include <linux/sem.h> #include <linux/mutex.h> #define PHONE_NUM_DEVICES 256 /* * Active devices */ static struct phone_device *phone_device[PHONE_NUM_DEVICES]; static DEFINE_MUTEX(phone_lock); /* * Open a phone device. */ static int phone_open(struct inode *inode, struct file *file) { unsigned int minor = iminor(inode); int err = 0; struct phone_device *p; const struct file_operations *old_fops, *new_fops = NULL; if (minor >= PHONE_NUM_DEVICES) return -ENODEV; mutex_lock(&phone_lock); p = phone_device[minor]; if (p) new_fops = fops_get(p->f_op); if (!new_fops) { mutex_unlock(&phone_lock); request_module("char-major-%d-%d", PHONE_MAJOR, minor); mutex_lock(&phone_lock); p = phone_device[minor]; if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL) { err=-ENODEV; goto end; } } old_fops = file->f_op; file->f_op = new_fops; if (p->open) err = p->open(p, file); /* Tell the device it is open */ if (err) { fops_put(file->f_op); file->f_op = fops_get(old_fops); } fops_put(old_fops); end: mutex_unlock(&phone_lock); return err; } /* * Telephony For Linux device drivers request registration here. */ int phone_register_device(struct phone_device *p, int unit) { int base; int end; int i; base = 0; end = PHONE_NUM_DEVICES - 1; if (unit != PHONE_UNIT_ANY) { base = unit; end = unit + 1; /* enter the loop at least one time */ } mutex_lock(&phone_lock); for (i = base; i < end; i++) { if (phone_device[i] == NULL) { phone_device[i] = p; p->minor = i; mutex_unlock(&phone_lock); return 0; } } mutex_unlock(&phone_lock); return -ENFILE; } /* * Unregister an unused Telephony for linux device */ void phone_unregister_device(struct phone_device *pfd) { mutex_lock(&phone_lock); if (likely(phone_device[pfd->minor] == pfd)) phone_device[pfd->minor] = NULL; mutex_unlock(&phone_lock); } static const struct file_operations phone_fops = { .owner = THIS_MODULE, .open = phone_open, }; /* * Board init functions */ /* * Initialise Telephony for linux */ static int __init telephony_init(void) { printk(KERN_INFO "Linux telephony interface: v1.00\n"); if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) { printk("phonedev: unable to get major %d\n", PHONE_MAJOR); return -EIO; } return 0; } static void __exit telephony_exit(void) { unregister_chrdev(PHONE_MAJOR, "telephony"); } module_init(telephony_init); module_exit(telephony_exit); MODULE_LICENSE("GPL"); EXPORT_SYMBOL(phone_register_device); EXPORT_SYMBOL(phone_unregister_device);