/* dvbloop - A DVB Loopback Device
 * Copyright (C) 2006 Christian Praehauser, Deti Fliegl
 -----------------------------------------
 * File: dvblo.c
 * Desc: This is the module core
 * Date: October 2006
 * Author: Christian Praehauser <cpreahaus@cosy.sbg.ac.at>, Deti Fliegl <deti@fliegl.de>
 *
 * This file is released under the GPLv2.
 */

#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/version.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/stat.h>

#define DVBLO_DEFINE_GLOBALS 1

#include "dvblo.h"
#include "dvblo_char.h"
#include "dvblo_util.h"
static unsigned int dvblo_devcount = DVBLO_CHAR_DEVMAX;
static char *dvblo_dvb_macaddrv[DVBLO_DEVMAX];
static int dvblo_dvb_macaddrc = 0;

// dvblo_debug is a global symbol (should be available in all .c files)
unsigned int dvblo_debug = 0;
unsigned int dvblo_netceiver = 0;
unsigned int dvblo_autocreate = 0;
module_param_named (devcount, dvblo_devcount, uint, S_IRUGO);
MODULE_PARM_DESC (devcount, "The initial number of virtual DVB adapters");
module_param_named (autocreate, dvblo_autocreate, uint, S_IRUGO);
MODULE_PARM_DESC (autocreate, "Create DVB adapters on module load automatically");

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
module_param_array_named (macaddrs, dvblo_dvb_macaddrv, charp, &dvblo_dvb_macaddrc, S_IRUGO);

#else /*  */
module_param_array_named (macaddrs, dvblo_dvb_macaddrv, charp, dvblo_dvb_macaddrc, S_IRUGO);

#endif /*  */
MODULE_PARM_DESC (macaddrs, "A (comma-separated) list of MAC addresses assigned to the virtual DVB adapters");
module_param_named (debug, dvblo_debug, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC (debug, "The debug level. Higher values will generate more debug info");
module_param_named (netceiver, dvblo_netceiver, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC (netceiver, "Set to 1 to enable Netceiver specific hacks");
EXPORT_SYMBOL_GPL (dvblo_devcount);
EXPORT_SYMBOL_GPL (dvblo_dvb_macaddrv);
EXPORT_SYMBOL_GPL (dvblo_dvb_macaddrc);
EXPORT_SYMBOL_GPL (dvblo_debug);
EXPORT_SYMBOL_GPL (dvblo_netceiver);
MODULE_LICENSE ("GPL v2");
MODULE_AUTHOR ("Christian Praehauser / Deti Fliegl");
MODULE_DESCRIPTION ("DVB loopback device");
MODULE_VERSION (DVBLO_VERSION);

/// Module initialization level
static int initlev = 0;

/**
 * @note This function can cope with a partially initialized dvblo module
 * by inspecting the init_level member.
 * This is necessary because dvblo_cleanup() is used by dvb_init() in case of an
 * error during initialization
 */
static int dvblo_cleanup (void)
{
	int rv = SUCCESS, step, i = 0;

	/* cleanup dvblo module
	 * We rollback all init steps starting with the last one.
	 */
	for (step = initlev; step > 0; i = 0, step--) {

		/* The items of the switch statement resemble the initialization
		 * steps which were taken in dvblo_init()
		 *
		 * Yeah, I know it would be elegent to reverse the order of the
		 * switch entries (the highest init step at the top) and remove
		 * all break statements, so that when entering one init level (say 6)
		 * all other levels (below it, i.e. 5,4,3,2,1) are also processed by falling-through.
		 *
		 * The reason why we (un)do every step in a for loop is that
		 * we can easily check for errors (using the variable i) and
		 * report the step which failed and then continue (although it 
		 * might be dangerous).
		 */
		switch (step) {
		case 1:
			i = dvblo_char_exit ();
			break;
		default:
			mprintk (KERN_ERR, "Oops! Invalid init step: %i\n", i);
			break;
		}
		if (i < 0) {
			mprintk (KERN_ALERT, "cleanup of init step %i has failed. Continuing cleanup process. Expect more errors...\n", step);
			if (rv == SUCCESS)
				rv = i;
		}
	}
	return rv;
}

static int __init dvblo_init (void)
{
	int rv = SUCCESS, i;
	unsigned int devnum;
	struct dvblo_chardev_config devcfg;

	do {
		rv = dvblo_char_init ();
		if (rv < 0) {
			mprintk (KERN_ERR, "failed to initialize char driver\n");
			break;
		}
		initlev++;
		if (dvblo_devcount > 0) {

			/* open initial number of dvbloop devices */
			dprintk (DBGLEV_1, "adding %i " DVBLO_NAME " device%s...\n", dvblo_devcount, dvblo_devcount == 1 ? "" : "s");
			for (i = 0; i < dvblo_devcount && rv == SUCCESS; i++) {
				if (dvblo_dvb_macaddrc > i && dvblo_dvb_macaddrv[i] != NULL) {

					/* MAC address was specified for this device */
					rv = dvblo_parse_mac (dvblo_dvb_macaddrv[i], devcfg.dvbcfg.mac);
					if (rv < 0) {
						mprintk (KERN_ERR, "invalid MAC address: \"%s\"\n", dvblo_dvb_macaddrv[i]);
						break;
					}

					else {
						dprintk (DBGLEV_1, "Using MAC address %s for DVB adapter %d\n", dvblo_dvb_macaddrv[i], i);
						devcfg.dvbcfg.mac_valid = 1;
					}
				} else
					devcfg.dvbcfg.mac_valid = 0;
				rv = dvblo_char_add_dev (&devcfg, &devnum);
			}
			if (rv != SUCCESS) {
				mprintk (KERN_ERR, "FAILED to add DVB adapter %d\n", i);
				break;
			}
		}

		/* success */
		mprintk (KERN_INFO, "successfully initialized " DVBLO_LONGMANE "\n");
	} while (0);
	if (rv != SUCCESS) {
		mprintk (KERN_ERR, "FAILED to initialize " DVBLO_LONGMANE "\n");
		i = dvblo_cleanup ();
		if (i < 0)
			mprintk (KERN_ALERT, "dvblo_cleanup() returned %d\n", i);
	}
	return rv;
}

static void __exit dvblo_exit (void)
{
	int i;
	i = dvblo_cleanup ();
	if (i < 0)
		mprintk (KERN_ALERT, "dvblo_cleanup() returned %d\n", i);
}

module_init (dvblo_init);
module_exit (dvblo_exit);