/*
   * IUCV special message driver
   *
   * Copyright IBM Corp. 2003, 2009
   *
   * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
   *
   * 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, or (at your option)
   * any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/errno.h>
  #include <linux/device.h>
  #include <linux/slab.h>
  #include <net/iucv/iucv.h>
  #include <asm/cpcmd.h>
  #include <asm/ebcdic.h>
  #include "smsgiucv.h"
  
  struct smsg_callback {
  	struct list_head list;
  	const char *prefix;
  	int len;
  	void (*callback)(const char *from, char *str);
  };
  
  MODULE_AUTHOR
     ("(C) 2003 IBM Corporation by Martin Schwidefsky (schwidefsky@de.ibm.com)");
  MODULE_DESCRIPTION ("Linux for S/390 IUCV special message driver");
  
  static struct iucv_path *smsg_path;
  /* dummy device used as trigger for PM functions */
  static struct device *smsg_dev;
  
  static DEFINE_SPINLOCK(smsg_list_lock);
  static LIST_HEAD(smsg_list);
  static int iucv_path_connected;
  
  static int smsg_path_pending(struct iucv_path *, u8 ipvmid[8], u8 ipuser[16]);
  static void smsg_message_pending(struct iucv_path *, struct iucv_message *);
  
  static struct iucv_handler smsg_handler = {
  	.path_pending	 = smsg_path_pending,
  	.message_pending = smsg_message_pending,
  };
  
  static int smsg_path_pending(struct iucv_path *path, u8 ipvmid[8],
  			     u8 ipuser[16])
  {
  	if (strncmp(ipvmid, "*MSG    ", 8) != 0)
  		return -EINVAL;
  	/* Path pending from *MSG. */
  	return iucv_path_accept(path, &smsg_handler, "SMSGIUCV        ", NULL);
  }
  
  static void smsg_message_pending(struct iucv_path *path,
  				 struct iucv_message *msg)
  {
  	struct smsg_callback *cb;
  	unsigned char *buffer;
  	unsigned char sender[9];
  	int rc, i;
  
  	buffer = kmalloc(msg->length + 1, GFP_ATOMIC | GFP_DMA);
  	if (!buffer) {
  		iucv_message_reject(path, msg);
  		return;
  	}
  	rc = iucv_message_receive(path, msg, 0, buffer, msg->length, NULL);
  	if (rc == 0) {
  		buffer[msg->length] = 0;
  		EBCASC(buffer, msg->length);
  		memcpy(sender, buffer, 8);
  		sender[8] = 0;
  		/* Remove trailing whitespace from the sender name. */
  		for (i = 7; i >= 0; i--) {
  			if (sender[i] != ' ' && sender[i] != '\t')
  				break;
  			sender[i] = 0;
  		}
  		spin_lock(&smsg_list_lock);
  		list_for_each_entry(cb, &smsg_list, list)
  			if (strncmp(buffer + 8, cb->prefix, cb->len) == 0) {
  				cb->callback(sender, buffer + 8);
  				break;
  			}
  		spin_unlock(&smsg_list_lock);
  	}
  	kfree(buffer);
  }
  
  int smsg_register_callback(const char *prefix,
  			   void (*callback)(const char *from, char *str))
  {
  	struct smsg_callback *cb;
  
  	cb = kmalloc(sizeof(struct smsg_callback), GFP_KERNEL);
  	if (!cb)
  		return -ENOMEM;
  	cb->prefix = prefix;
  	cb->len = strlen(prefix);
  	cb->callback = callback;
  	spin_lock_bh(&smsg_list_lock);
  	list_add_tail(&cb->list, &smsg_list);
  	spin_unlock_bh(&smsg_list_lock);
  	return 0;
  }
  
  void smsg_unregister_callback(const char *prefix,
  			      void (*callback)(const char *from,
  					       char *str))
  {
  	struct smsg_callback *cb, *tmp;
  
  	spin_lock_bh(&smsg_list_lock);
  	cb = NULL;
  	list_for_each_entry(tmp, &smsg_list, list)
  		if (tmp->callback == callback &&
  		    strcmp(tmp->prefix, prefix) == 0) {
  			cb = tmp;
  			list_del(&cb->list);
  			break;
  		}
  	spin_unlock_bh(&smsg_list_lock);
  	kfree(cb);
  }
  
  static int smsg_pm_freeze(struct device *dev)
  {
  #ifdef CONFIG_PM_DEBUG
  	printk(KERN_WARNING "smsg_pm_freeze
  ");
  #endif
  	if (smsg_path && iucv_path_connected) {
  		iucv_path_sever(smsg_path, NULL);
  		iucv_path_connected = 0;
  	}
  	return 0;
  }
  
  static int smsg_pm_restore_thaw(struct device *dev)
  {
  	int rc;
  
  #ifdef CONFIG_PM_DEBUG
  	printk(KERN_WARNING "smsg_pm_restore_thaw
  ");
  #endif
  	if (smsg_path && !iucv_path_connected) {
  		memset(smsg_path, 0, sizeof(*smsg_path));
  		smsg_path->msglim = 255;
  		smsg_path->flags = 0;
  		rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
  				       NULL, NULL, NULL);
  #ifdef CONFIG_PM_DEBUG
  		if (rc)
  			printk(KERN_ERR
  			       "iucv_path_connect returned with rc %i
  ", rc);
  #endif
  		if (!rc)
  			iucv_path_connected = 1;
  		cpcmd("SET SMSG IUCV", NULL, 0, NULL);
  	}
  	return 0;
  }
  
  static const struct dev_pm_ops smsg_pm_ops = {
  	.freeze = smsg_pm_freeze,
  	.thaw = smsg_pm_restore_thaw,
  	.restore = smsg_pm_restore_thaw,
  };
  
  static struct device_driver smsg_driver = {
  	.owner = THIS_MODULE,
  	.name = SMSGIUCV_DRV_NAME,
  	.bus  = &iucv_bus,
  	.pm = &smsg_pm_ops,
  };
  
  static void __exit smsg_exit(void)
  {
  	cpcmd("SET SMSG IUCV", NULL, 0, NULL);
  	device_unregister(smsg_dev);
  	iucv_unregister(&smsg_handler, 1);
  	driver_unregister(&smsg_driver);
  }
  
  static int __init smsg_init(void)
  {
  	int rc;
  
  	if (!MACHINE_IS_VM) {
  		rc = -EPROTONOSUPPORT;
  		goto out;
  	}
  	rc = driver_register(&smsg_driver);
  	if (rc != 0)
  		goto out;
  	rc = iucv_register(&smsg_handler, 1);
  	if (rc)
  		goto out_driver;
  	smsg_path = iucv_path_alloc(255, 0, GFP_KERNEL);
  	if (!smsg_path) {
  		rc = -ENOMEM;
  		goto out_register;
  	}
  	rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
  			       NULL, NULL, NULL);
  	if (rc)
  		goto out_free_path;
  	else
  		iucv_path_connected = 1;
  	smsg_dev = kzalloc(sizeof(struct device), GFP_KERNEL);
  	if (!smsg_dev) {
  		rc = -ENOMEM;
  		goto out_free_path;
  	}
  	dev_set_name(smsg_dev, "smsg_iucv");
  	smsg_dev->bus = &iucv_bus;
  	smsg_dev->parent = iucv_root;
  	smsg_dev->release = (void (*)(struct device *))kfree;
  	smsg_dev->driver = &smsg_driver;
  	rc = device_register(smsg_dev);
  	if (rc)
  		goto out_put;
  
  	cpcmd("SET SMSG IUCV", NULL, 0, NULL);
  	return 0;
  
  out_put:
  	put_device(smsg_dev);
  out_free_path:
  	iucv_path_free(smsg_path);
  	smsg_path = NULL;
  out_register:
  	iucv_unregister(&smsg_handler, 1);
  out_driver:
  	driver_unregister(&smsg_driver);
  out:
  	return rc;
  }
  
  module_init(smsg_init);
  module_exit(smsg_exit);
  MODULE_LICENSE("GPL");
  
  EXPORT_SYMBOL(smsg_register_callback);
  EXPORT_SYMBOL(smsg_unregister_callback);