/*****************************************************************************
* sdlamain.c	WANPIPE(tm) Multiprotocol WAN Link Driver.  Main module.
*
* Author:	Gene Kozin	<genek@compuserve.com>
*
* Copyright:	(c) 1995-1997 Sangoma Technologies 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.
* ============================================================================
* Jan 02, 1997	Gene Kozin	Initial version.
*****************************************************************************/

#if	!defined(__KERNEL__) || !defined(MODULE)
#error	This code MUST be compiled as a kernel module!
#endif

#include <linux/config.h>	/* OS configuration options */
#include <linux/stddef.h>	/* offsetof(), etc. */
#include <linux/errno.h>	/* return codes */
#include <linux/string.h>	/* inline memset(), etc. */
#include <linux/malloc.h>	/* kmalloc(), kfree() */
#include <linux/kernel.h>	/* printk(), and other useful stuff */
#include <linux/module.h>	/* support for loadable modules */
#include <linux/ioport.h>	/* request_region(), release_region() */
#include <linux/tqueue.h>	/* for kernel task queues */
#include <linux/router.h>	/* WAN router definitions */
#include <linux/wanpipe.h>	/* WANPIPE common user API definitions */
#include <asm/segment.h>	/* kernel <-> user copy */

/****** Defines & Macros ****************************************************/

#ifdef	_DEBUG_
#define	STATIC
#else
#define	STATIC		static
#endif

#define	DRV_VERSION	3		/* version number */
#define	DRV_RELEASE	0		/* release (minor version) number */
#define	MAX_CARDS	8		/* max number of adapters */

#ifndef	CONFIG_WANPIPE_CARDS		/* configurable option */
#define	CONFIG_WANPIPE_CARDS 1
#endif

#define	CMD_OK		0		/* normal firmware return code */
#define	CMD_TIMEOUT	0xFF		/* firmware command timed out */
#define	MAX_CMD_RETRY	10		/* max number of firmware retries */

/****** Function Prototypes *************************************************/

/* Module entry points */
int init_module (void);
void cleanup_module (void);

/* WAN link driver entry points */
static int setup    (wan_device_t* wandev, wandev_conf_t* conf);
static int shutdown (wan_device_t* wandev);
static int ioctl    (wan_device_t* wandev, unsigned cmd, unsigned long arg);

/* IOCTL hanlers */
static int ioctl_dump	(sdla_t* card, sdla_dump_t* u_dump);
static int ioctl_exec	(sdla_t* card, sdla_exec_t* u_exec);

/* Miscellaneous functions */
STATIC void sdla_isr	(int irq, void* dev_id, struct pt_regs *regs);
STATIC void sdla_poll	(void* data);

/****** Global Data **********************************************************
 * Note: All data must be explicitly initialized!!!
 */

/* private data */
static char drvname[]	= "wanpipe";
static char fullname[]	= "WANPIPE(tm) Multiprotocol Driver";
static char copyright[]	= "(c) 1995-1996 Sangoma Technologies Inc.";
static int ncards = CONFIG_WANPIPE_CARDS;
static int active = 0;			/* number of active cards */
static sdla_t* card_array = NULL;	/* adapter data space */

/* Task queue element for creating a 'thread' */
static struct tq_struct sdla_tq =
{
	NULL,		/* .next */
	0,		/* .sync */
	&sdla_poll,	/* .routine */
	NULL		/* .data */
}; 

/******* Kernel Loadable Module Entry Points ********************************/

/*============================================================================
 * Module 'insert' entry point.
 * o print announcement
 * o allocate adapter data space
 * o initialize static data
 * o register all cards with WAN router
 * o calibrate SDLA shared memory access delay.
 *
 * Return:	0	Ok
 *		< 0	error.
 * Context:	process
 */
int init_module (void)
{
	int cnt, err = 0;

	printk(KERN_INFO "%s v%u.%u %s\n",
		fullname, DRV_VERSION, DRV_RELEASE, copyright)
	;

	/* Verify number of cards and allocate adapter data space */
	ncards = min(ncards, MAX_CARDS);
	ncards = max(ncards, 1);
	card_array = kmalloc(sizeof(sdla_t) * ncards, GFP_KERNEL);
	if (card_array == NULL)
		return -ENOMEM
	;
	memset(card_array, 0, sizeof(sdla_t) * ncards);

	/* Register adapters with WAN router */
	for (cnt = 0; cnt < ncards; ++cnt)
	{
		sdla_t* card = &card_array[cnt];
		wan_device_t* wandev = &card->wandev;

		sprintf(card->devname, "%s%d", drvname, cnt + 1);
		wandev->magic    = ROUTER_MAGIC;
		wandev->name     = card->devname;
		wandev->private  = card;
		wandev->setup    = &setup;
		wandev->shutdown = &shutdown;
		wandev->ioctl    = &ioctl;
		err = register_wandev(wandev);
		if (err)
		{
			printk(KERN_ERR
				"%s: %s registration failed with error %d!\n",
				drvname, card->devname, err)
			;
			break;
		}
	}
	if (cnt) ncards = cnt;	/* adjust actual number of cards */
	else kfree(card_array);
	return err;
}

/*============================================================================
 * Module 'remove' entry point.
 * o unregister all adapters from the WAN router
 * o release all remaining system resources
 */
void cleanup_module (void)
{
	int i;

	for (i = 0; i < ncards; ++i)
	{
		sdla_t* card = &card_array[i];
		unregister_wandev(card->devname);
	}
	kfree(card_array);
}

/******* WAN Device Driver Entry Points *************************************/

/*============================================================================
 * Setup/confugure WAN link driver.
 * o check adapter state
 * o make sure firmware is present in configuration
 * o make sure I/O port and IRQ are specified
 * o make sure I/O region is available
 * o allocate interrupt vector
 * o setup SDLA hardware
 * o call appropriate routine to perform protocol-specific initialization
 * o mark I/O region as used
 * o if this is the first active card, then schedule background task
 *
 * This function is called when router handles ROUTER_SETUP IOCTL. The
 * configuration structure is in kernel memory (including extended data, if
 * any).
 */
static int setup (wan_device_t* wandev, wandev_conf_t* conf)
{
	sdla_t* card;
	int err = 0;
	int irq;

	/* Sanity checks */
	if ((wandev == NULL) || (wandev->private == NULL) || (conf == NULL))
		return -EFAULT
	;
	card = wandev->private;
	if (wandev->state != WAN_UNCONFIGURED)
		return -EBUSY		/* already configured */
	;
	if (!conf->data_size || (conf->data == NULL))
	{
		printk(KERN_ERR
			"%s: firmware not found in configuration data!\n",
			wandev->name)
		;
		return -EINVAL;
	}
	if (conf->ioport <= 0)
	{
		printk(KERN_ERR
			"%s: can't configure without I/O port address!\n",
			wandev->name)
		;
		return -EINVAL;
	}
	if (conf->irq <= 0)
	{
		printk(KERN_ERR "%s: can't configure without IRQ!\n",
			wandev->name)
		;
		return -EINVAL;
	}

	/* Make sure I/O port region is available */
	if (check_region(conf->ioport, SDLA_MAXIORANGE))
	{
		printk(KERN_ERR "%s: I/O region 0x%X - 0x%X is in use!\n",
			wandev->name, conf->ioport,
			conf->ioport + SDLA_MAXIORANGE)
		;
		return -EINVAL;
	}

	/* Allocate IRQ */
	irq = (conf->irq == 2) ? 9 : conf->irq;	/* IRQ2 -> IRQ9 */
	if (request_irq(irq, sdla_isr, 0, wandev->name, card))
	{
		printk(KERN_ERR "%s: can't reserve IRQ %d!\n",
			wandev->name, irq)
		;
		return -EINVAL;
	}

	/* Configure hardware, load firmware, etc. */
	memset(&card->hw, 0, sizeof(sdlahw_t));
	card->hw.port    = conf->ioport;
	card->hw.irq     = (conf->irq == 9) ? 2 : conf->irq;
	card->hw.dpmbase = conf->maddr;
	card->hw.dpmsize = SDLA_WINDOWSIZE;
	card->hw.type    = conf->hw_opt[0];
	card->hw.pclk    = conf->hw_opt[1];
	err = sdla_setup(&card->hw, conf->data, conf->data_size);
	if (err)
	{
		free_irq(irq, card);
		return err;
	}

	/* Intialize WAN device data space */
	wandev->irq       = irq;
	wandev->dma       = 0;
	wandev->ioport    = card->hw.port;
	wandev->maddr     = card->hw.dpmbase;
	wandev->msize     = card->hw.dpmsize;
	wandev->hw_opt[0] = card->hw.type;
	wandev->hw_opt[1] = card->hw.pclk;
	wandev->hw_opt[2] = card->hw.memory;
	wandev->hw_opt[3] = card->hw.fwid;

	/* Protocol-specific initialization */
	switch (card->hw.fwid)
	{
#ifdef	CONFIG_WANPIPE_X25
	case SFID_X25_502:
	case SFID_X25_508:
		err = wpx_init(card, conf);
		break;
#endif

#ifdef	CONFIG_WANPIPE_FR
	case SFID_FR502:
	case SFID_FR508:
		err = wpf_init(card, conf);
		break;
#endif

#ifdef	CONFIG_WANPIPE_PPP
	case SFID_PPP502:
	case SFID_PPP508:
		err = wpp_init(card, conf);
		break;
#endif

	default:
		printk(KERN_ERR "%s: this firmware is not supported!\n",
			wandev->name)
		;
		err = -EINVAL;
	}
	if (err)
	{
		sdla_down(&card->hw);
		free_irq(irq, card);
		return err;
	}
  	/* Reserve I/O region and schedule background task */
	request_region(card->hw.port, card->hw.io_range, wandev->name);
	if (++active == 1)
		queue_task(&sdla_tq, &tq_scheduler)
	;
	wandev->critical = 0;
	return 0;
}

/*============================================================================
 * Shut down WAN link driver. 
 * o shut down adapter hardware
 * o release system resources.
 *
 * This function is called by the router when device is being unregistered or
 * when it handles ROUTER_DOWN IOCTL.
 */
static int shutdown (wan_device_t* wandev)
{
	sdla_t* card;

	/* sanity checks */
	if ((wandev == NULL) || (wandev->private == NULL))
		return -EFAULT
	;
	if (wandev->state == WAN_UNCONFIGURED)
		return 0
	;
	if (test_and_set_bit(0, (void*)&wandev->critical))
		return -EAGAIN
	;
	card = wandev->private;
	wandev->state = WAN_UNCONFIGURED;
	if (--active == 0) schedule();	/* stop background thread */
	sdla_down(&card->hw);
	free_irq(wandev->irq, card);
	release_region(card->hw.port, card->hw.io_range);
	wandev->critical = 0;
	return 0;
}

/*============================================================================
 * Driver I/O control. 
 * o verify arguments
 * o perform requested action
 *
 * This function is called when router handles one of the reserved user
 * IOCTLs.  Note that 'arg' stil points to user address space.
 */
static int ioctl (wan_device_t* wandev, unsigned cmd, unsigned long arg)
{
	int err;

	/* sanity checks */
	if ((wandev == NULL) || (wandev->private == NULL))
		return -EFAULT
	;
	if (wandev->state == WAN_UNCONFIGURED)
		return -ENODEV
	;
	if (test_and_set_bit(0, (void*)&wandev->critical))
		return -EAGAIN
	;
	switch (cmd)
	{
	case WANPIPE_DUMP:
		err = ioctl_dump(wandev->private, (void*)arg);
		break;

	case WANPIPE_EXEC:
		err = ioctl_exec(wandev->private, (void*)arg);
		break;

	default:
		err = -EINVAL;
	}
	wandev->critical = 0;
	return err;
}

/****** Driver IOCTL Hanlers ************************************************/

/*============================================================================
 * Dump adpater memory to user buffer.
 * o verify request structure
 * o copy request structure to kernel data space
 * o verify length/offset
 * o verify user buffer
 * o copy adapter memory image to user buffer
 *
 * Note: when dumping memory, this routine switches curent dual-port memory
 *	 vector, so care must be taken to avoid racing conditions.
 */
static int ioctl_dump (sdla_t* card, sdla_dump_t* u_dump)
{
	sdla_dump_t dump;
	unsigned winsize;
	unsigned long oldvec;	/* DPM window vector */
	int err = 0;

	if ((u_dump == NULL) ||
	    verify_area(VERIFY_READ, u_dump, sizeof(sdla_dump_t)))
		return -EFAULT
	;
	memcpy_fromfs((void*)&dump, (void*)u_dump, sizeof(sdla_dump_t));
	if ((dump.magic != WANPIPE_MAGIC) ||
	    (dump.offset + dump.length > card->hw.memory))
		return -EINVAL
	;
	if ((dump.ptr == NULL) ||
	    verify_area(VERIFY_WRITE, dump.ptr, dump.length))
		return -EFAULT
	;

	winsize = card->hw.dpmsize;
        cli();				/* >>> critical section start <<< */
	oldvec = card->hw.vector;
	while (dump.length)
	{
		unsigned pos = dump.offset % winsize;	/* current offset */
		unsigned long vec = dump.offset - pos;	/* current vector */
		unsigned len = (dump.length > (winsize - pos)) ?
			(winsize - pos) : dump.length
		;
		if (sdla_mapmem(&card->hw, vec) != 0)	/* relocate window */
		{
			err = -EIO;
			break;
		}
		memcpy_tofs((void*)(dump.ptr),
			(void*)(card->hw.dpmbase + pos), len)
		;
		dump.length     -= len;
		dump.offset     += len;
		(char*)dump.ptr += len;
	}
	sdla_mapmem(&card->hw, oldvec);	/* restore DPM window position */
	sti();				/* >>> critical section end <<< */
	return err;
}

/*============================================================================
 * Execute adapter firmware command.
 * o verify request structure
 * o copy request structure to kernel data space
 * o call protocol-specific 'exec' function
 */
static int ioctl_exec (sdla_t* card, sdla_exec_t* u_exec)
{
	sdla_exec_t exec;

	if (card->exec == NULL)
		return -ENODEV
	;
	if ((u_exec == NULL) ||
	    verify_area(VERIFY_READ, u_exec, sizeof(sdla_exec_t)))
		return -EFAULT
	;
	memcpy_fromfs((void*)&exec, (void*)u_exec, sizeof(sdla_exec_t));
	if ((exec.magic != WANPIPE_MAGIC) || (exec.cmd == NULL))
		return -EINVAL
	;
	return card->exec(card, exec.cmd, exec.data);
}

/******* Miscellaneous ******************************************************/

/*============================================================================
 * SDLA Interrupt Service Routine.
 * o acknowledge SDLA hardware interrupt.
 * o call protocol-specific interrupt service routine, if any.
 */
STATIC void sdla_isr (int irq, void* dev_id, struct pt_regs *regs)
{
#define	card	((sdla_t*)dev_id)

	if (!card || (card->wandev.state == WAN_UNCONFIGURED))
		return
	;
	if (card->in_isr)
	{
		printk(KERN_WARNING "%s: interrupt re-entrancy on IRQ %d!\n",
			card->devname, card->wandev.irq)
		;
		return;
	}
	card->in_isr = 1;
	sdla_intack(&card->hw);
	if (card->isr) card->isr(card);
	card->in_isr = 0;

#undef	card
}

/*============================================================================
 * SDLA polling routine.
 * This routine simulates kernel thread to perform various housekeeping job.
 *
 * o for each configured device call its poll() routine
 * o if there is at least one active card, then reschedule itself once again
 */
STATIC void sdla_poll (void* data)
{
	int i;

	for (i = 0; i < ncards; ++i)
	{
		sdla_t* card = &card_array[i];

		if ((card->wandev.state != WAN_UNCONFIGURED) && card->poll &&
		    !test_and_set_bit(0, (void*)&card->wandev.critical))
		{
			card->poll(card);
			card->wandev.critical = 0;
		}
	}
	if (active) queue_task(&sdla_tq, &tq_scheduler);
}

/*============================================================================
 * This routine is called by the protocol-specific modules when network
 * interface is being open.  The only reason we need this, is because we
 * have to call MOD_INC_USE_COUNT, but cannot include 'module.h' where it's
 * defined more than once into the same kernel module.
 */
void wanpipe_open (sdla_t* card)
{
	++card->open_cnt;
	MOD_INC_USE_COUNT;
}

/*============================================================================
 * This routine is called by the protocol-specific modules when network
 * interface is being closed.  The only reason we need this, is because we
 * have to call MOD_DEC_USE_COUNT, but cannot include 'module.h' where it's
 * defined more than once into the same kernel module.
 */
void wanpipe_close (sdla_t* card)
{
	--card->open_cnt;
	MOD_DEC_USE_COUNT;
}

/*============================================================================
 * Set WAN device state.
 */
void wanpipe_set_state (sdla_t* card, int state)
{
	unsigned long flags;

	save_flags(flags);
	cli();
	if (card->wandev.state != state)
	{
		switch (state)
		{
		case WAN_CONNECTED:
			printk (KERN_INFO "%s: link connected!\n",
				card->devname)
			;
			break;

		case WAN_CONNECTING:
			printk (KERN_INFO "%s: link connecting...\n",
				card->devname)
			;
			break;

		case WAN_DISCONNECTED:
			printk (KERN_INFO "%s: link disconnected!\n",
				card->devname)
			;
			break;
		}
		card->wandev.state = state;
	}
	card->state_tick = jiffies;
	restore_flags(flags);
}

/****** End *****************************************************************/