/*
 * $Id: iforce.c,v 1.1.1.1 2003/06/23 22:18:26 jharrell Exp $
 *
 *  Copyright (c) 2000-2001 Vojtech Pavlik <vojtech@suse.cz>
 *  Copyright (c) 2001 Johann Deneux <deneux@ifrance.com>
 *
 *  USB/RS232 I-Force joysticks and wheels.
 *
 *  Sponsored by SuSE
 */

/*
 * 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.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Should you need to contact me, the author, you can do so either by
 * e-mail - mail your message to <vojtech@suse.cz>, or by paper mail:
 * Vojtech Pavlik, Ucitelska 1576, Prague 8, 182 00 Czech Republic
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/usb.h>
#include <linux/serio.h>
#include <linux/config.h>

/* FF: This module provides arbitrary resource management routines.
 * I use it to manage the device's memory.
 * Despite the name of this module, I am *not* going to access the ioports.
 */
#include <linux/ioport.h>

MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>, Johann Deneux <deneux@ifrance.com>");
MODULE_DESCRIPTION("USB/RS232 I-Force joysticks and wheels driver");
MODULE_LICENSE("GPL");

#define IFORCE_MAX_LENGTH	16

#if defined(CONFIG_INPUT_IFORCE_232) || defined(CONFIG_INPUT_IFORCE_232_MODULE)
#define IFORCE_232	1
#endif
#if defined(CONFIG_INPUT_IFORCE_USB) || defined(CONFIG_INPUT_IFORCE_USB_MODULE)
#define IFORCE_USB	2
#endif

#define FF_EFFECTS_MAX	32

/* Each force feedback effect is made of one core effect, which can be
 * associated to at most to effect modifiers
 */
#define FF_MOD1_IS_USED		0
#define FF_MOD2_IS_USED		1
#define FF_CORE_IS_USED		2
#define FF_CORE_IS_PLAYED	3
#define FF_MODCORE_MAX		3

struct iforce_core_effect {
	/* Information about where modifiers are stored in the device's memory */
	struct resource mod1_chunk;
	struct resource mod2_chunk;
	unsigned long flags[NBITS(FF_MODCORE_MAX)];
};

#define FF_CMD_EFFECT		0x010e
#define FF_CMD_SHAPE		0x0208
#define FF_CMD_MAGNITUDE	0x0303
#define FF_CMD_PERIOD		0x0407
#define FF_CMD_INTERACT		0x050a

#define FF_CMD_AUTOCENTER	0x4002
#define FF_CMD_PLAY		0x4103
#define FF_CMD_ENABLE		0x4201
#define FF_CMD_GAIN		0x4301

#define FF_CMD_QUERY		0xff01

static signed short btn_joystick[] = { BTN_TRIGGER, BTN_TOP, BTN_THUMB, BTN_TOP2, BTN_BASE,
	BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_BASE5, BTN_A, BTN_B, BTN_C, BTN_DEAD, -1 };
static signed short btn_wheel[] =    { BTN_TRIGGER, BTN_TOP, BTN_THUMB, BTN_TOP2, BTN_BASE,
	BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_BASE5, BTN_A, BTN_B, BTN_C, -1 };
static signed short abs_joystick[] = { ABS_X, ABS_Y, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y, -1 };
static signed short abs_wheel[] =    { ABS_WHEEL, ABS_GAS, ABS_BRAKE, ABS_HAT0X, ABS_HAT0Y, -1 };
static signed short ff_iforce[] =    { FF_PERIODIC, FF_CONSTANT, FF_SPRING, FF_FRICTION,
	FF_SQUARE, FF_TRIANGLE, FF_SINE, FF_SAW_UP, FF_SAW_DOWN, FF_GAIN, FF_AUTOCENTER, -1 };

static struct iforce_device {
	u16 idvendor;
	u16 idproduct;
	char *name;
	signed short *btn;
	signed short *abs;
	signed short *ff;
} iforce_device[] = {
	{ 0x046d, 0xc281, "Logitech WingMan Force",			btn_joystick, abs_joystick, ff_iforce },
	{ 0x046d, 0xc291, "Logitech WingMan Formula Force",		btn_wheel, abs_wheel, ff_iforce },
	{ 0x05ef, 0x020a, "AVB Top Shot Pegasus",			btn_joystick, abs_joystick, ff_iforce },
	{ 0x05ef, 0x8884, "AVB Mag Turbo Force",			btn_wheel, abs_wheel, ff_iforce },
	{ 0x06f8, 0x0001, "Guillemot Race Leader Force Feedback",	btn_wheel, abs_wheel, ff_iforce },
	{ 0x0000, 0x0000, "Unknown I-Force Device [%04x:%04x]",		btn_joystick, abs_joystick, ff_iforce }
};

struct iforce {
	struct input_dev dev;		/* Input device interface */
	struct iforce_device *type;
	char name[64];
	int open;
	int bus;

	unsigned char data[IFORCE_MAX_LENGTH];
	unsigned char edata[IFORCE_MAX_LENGTH];
	u16 ecmd;
	u16 expect_packet;

#ifdef IFORCE_232
	struct serio *serio;		/* RS232 transfer */
	int idx, pkt, len, id;
	unsigned char csum;
#endif
#ifdef IFORCE_USB
	struct usb_device *usbdev;	/* USB transfer */
	struct urb irq, out, ctrl;
	devrequest dr;
#endif
					/* Force Feedback */
	wait_queue_head_t wait;
	struct resource device_memory;
	struct iforce_core_effect core_effects[FF_EFFECTS_MAX];
};

static struct {
	__s32 x;
	__s32 y;
} iforce_hat_to_axis[16] = {{ 0,-1}, { 1,-1}, { 1, 0}, { 1, 1}, { 0, 1}, {-1, 1}, {-1, 0}, {-1,-1}};

/* Get hi and low bytes of a 16-bits int */
#define HI(a)	((unsigned char)((a) >> 8))
#define LO(a)	((unsigned char)((a) & 0xff))

/* Encode a time value */
#define TIME_SCALE(a)	((a) == 0xffff ? 0xffff : (a) * 1000 / 256)

static void dump_packet(char *msg, u16 cmd, unsigned char *data)
{
	int i;

	printk(KERN_DEBUG "iforce.c: %s ( cmd = %04x, data = ", msg, cmd);
	for (i = 0; i < LO(cmd); i++)
		printk("%02x ", data[i]);
	printk(")\n");
}

/*
 * Send a packet of bytes to the device
 */
static void send_packet(struct iforce *iforce, u16 cmd, unsigned char* data)
{
	switch (iforce->bus) {

#ifdef IFORCE_232
		case IFORCE_232: {

			int i;
			unsigned char csum = 0x2b ^ HI(cmd) ^ LO(cmd);

			serio_write(iforce->serio, 0x2b);
			serio_write(iforce->serio, HI(cmd));
			serio_write(iforce->serio, LO(cmd));

			for (i = 0; i < LO(cmd); i++) {
				serio_write(iforce->serio, data[i]);
				csum = csum ^ data[i];
			}

			serio_write(iforce->serio, csum);
			return;
		}
#endif
#ifdef IFORCE_USB
		case IFORCE_USB: {

			DECLARE_WAITQUEUE(wait, current);
			int timeout = HZ; /* 1 second */

			memcpy(iforce->out.transfer_buffer + 1, data, LO(cmd));
			((char*)iforce->out.transfer_buffer)[0] = HI(cmd);
			iforce->out.transfer_buffer_length = LO(cmd) + 2;
			iforce->out.dev = iforce->usbdev;

			set_current_state(TASK_INTERRUPTIBLE);
			add_wait_queue(&iforce->wait, &wait);

			if (usb_submit_urb(&iforce->out)) {
				set_current_state(TASK_RUNNING);
				remove_wait_queue(&iforce->wait, &wait);
				return;
			}

			while (timeout && iforce->out.status == -EINPROGRESS)
				timeout = schedule_timeout(timeout);

			set_current_state(TASK_RUNNING);
			remove_wait_queue(&iforce->wait, &wait);

			if (!timeout)
				usb_unlink_urb(&iforce->out);

			return;
		}
#endif
	}
}

static void iforce_process_packet(struct iforce *iforce, u16 cmd, unsigned char *data)
{
	struct input_dev *dev = &iforce->dev;
	int i;

#ifdef IFORCE_232
	if (HI(iforce->expect_packet) == HI(cmd)) {
		iforce->expect_packet = 0;
		iforce->ecmd = cmd;
		memcpy(iforce->edata, data, IFORCE_MAX_LENGTH);
		if (waitqueue_active(&iforce->wait))
			wake_up(&iforce->wait);
	}
#endif

	if (!iforce->type)
		return;

	switch (HI(cmd)) {

		case 0x01:	/* joystick position data */
		case 0x03:	/* wheel position data */

			if (HI(cmd) == 1) {
				input_report_abs(dev, ABS_X, (__s16) (((__s16)data[1] << 8) | data[0]));
				input_report_abs(dev, ABS_Y, (__s16) (((__s16)data[3] << 8) | data[2]));
				input_report_abs(dev, ABS_THROTTLE, 255 - data[4]);
			} else {
				input_report_abs(dev, ABS_WHEEL, (__s16) (((__s16)data[1] << 8) | data[0]));
				input_report_abs(dev, ABS_GAS,   255 - data[2]);
				input_report_abs(dev, ABS_BRAKE, 255 - data[3]);
			}

			input_report_abs(dev, ABS_HAT0X, iforce_hat_to_axis[data[6] >> 4].x);
			input_report_abs(dev, ABS_HAT0Y, iforce_hat_to_axis[data[6] >> 4].y);

			for (i = 0; iforce->type->btn[i] >= 0; i++)
				input_report_key(dev, iforce->type->btn[i], data[(i >> 3) + 5] & (1 << (i & 7)));

			break;

		case 0x02:	/* status report */

			input_report_key(dev, BTN_DEAD, data[0] & 0x02);
			break;
	}
}

static int get_id_packet(struct iforce *iforce, char *packet)
{
	DECLARE_WAITQUEUE(wait, current);
	int timeout = HZ; /* 1 second */

	switch (iforce->bus) {

#ifdef IFORCE_USB
		case IFORCE_USB:

			iforce->dr.request = packet[0];
			iforce->ctrl.dev = iforce->usbdev;

			set_current_state(TASK_INTERRUPTIBLE);
			add_wait_queue(&iforce->wait, &wait);

			if (usb_submit_urb(&iforce->ctrl)) {
				set_current_state(TASK_RUNNING);
				remove_wait_queue(&iforce->wait, &wait);
				return -1;
			}

			while (timeout && iforce->ctrl.status == -EINPROGRESS)
				timeout = schedule_timeout(timeout);

			set_current_state(TASK_RUNNING);
			remove_wait_queue(&iforce->wait, &wait);

			if (!timeout) {
				usb_unlink_urb(&iforce->ctrl);
				return -1;
			}

			break;
#endif
#ifdef IFORCE_232
		case IFORCE_232:

			iforce->expect_packet = FF_CMD_QUERY;
			send_packet(iforce, FF_CMD_QUERY, packet);

			set_current_state(TASK_INTERRUPTIBLE);
			add_wait_queue(&iforce->wait, &wait);

			while (timeout && iforce->expect_packet)
				timeout = schedule_timeout(timeout);

			set_current_state(TASK_RUNNING);
			remove_wait_queue(&iforce->wait, &wait);

			if (!timeout) {
				iforce->expect_packet = 0;
				return -1;
			}

			break;
#endif
	}

	return -(iforce->edata[0] != packet[0]);
}

static int iforce_open(struct input_dev *dev)
{
	struct iforce *iforce = dev->private;

	switch (iforce->bus) {
#ifdef IFORCE_USB
		case IFORCE_USB:
			if (iforce->open++)
				break;
			iforce->irq.dev = iforce->usbdev;
			if (usb_submit_urb(&iforce->irq))
					return -EIO;
			break;
#endif
	}
	return 0;
}

static void iforce_close(struct input_dev *dev)
{
	struct iforce *iforce = dev->private;

	switch (iforce->bus) {
#ifdef IFORCE_USB
		case IFORCE_USB:
			if (!--iforce->open)
				usb_unlink_urb(&iforce->irq);
			break;
#endif
	}
}

/*
 * Start or stop playing an effect
 */

static int iforce_input_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{
	struct iforce* iforce = (struct iforce*)(dev->private);
	unsigned char data[3];

	printk(KERN_DEBUG "iforce.c: input_event(type = %d, code = %d, value = %d)\n", type, code, value);

	if (type != EV_FF)
		return -1;

	switch (code) {

		case FF_GAIN:

			data[0] = value >> 9;
			send_packet(iforce, FF_CMD_GAIN, data);

			return 0;

		case FF_AUTOCENTER:

			data[0] = 0x03;
			data[1] = value >> 9;
			send_packet(iforce, FF_CMD_AUTOCENTER, data);

			data[0] = 0x04;
			data[1] = 0x01;
			send_packet(iforce, FF_CMD_AUTOCENTER, data);

			return 0;

		default: /* Play an effect */

			if (code >= iforce->dev.ff_effects_max)
				return -1;

			data[0] = LO(code);
			data[1] = (value > 0) ? ((value > 1) ? 0x41 : 0x01) : 0;
			data[2] = LO(value);
			send_packet(iforce, FF_CMD_PLAY, data);

			return 0;
	}

	return -1;
}

/*
 * Set the magnitude of a constant force effect
 * Return error code
 *
 * Note: caller must ensure exclusive access to device
 */

static int make_magnitude_modifier(struct iforce* iforce,
	struct resource* mod_chunk, __s16 level)
{
	unsigned char data[3];

	if (allocate_resource(&(iforce->device_memory), mod_chunk, 2,
		iforce->device_memory.start, iforce->device_memory.end, 2L,
		NULL, NULL)) {
		return -ENOMEM;
	}

	data[0] = LO(mod_chunk->start);
	data[1] = HI(mod_chunk->start);
	data[2] = HI(level);

	send_packet(iforce, FF_CMD_MAGNITUDE, data);

	return 0;
}

/*
 * Upload the component of an effect dealing with the period, phase and magnitude
 */

static int make_period_modifier(struct iforce* iforce, struct resource* mod_chunk,
	__s16 magnitude, __s16 offset, u16 period, u16 phase)
{
	unsigned char data[7];

	period = TIME_SCALE(period);

	if (allocate_resource(&(iforce->device_memory), mod_chunk, 0x0c,
		iforce->device_memory.start, iforce->device_memory.end, 2L,
		NULL, NULL)) {
		return -ENOMEM;
	}

	data[0] = LO(mod_chunk->start);
	data[1] = HI(mod_chunk->start);

	data[2] = HI(magnitude);
	data[3] = HI(offset);
	data[4] = HI(phase);

	data[5] = LO(period);
	data[6] = HI(period);

	send_packet(iforce, FF_CMD_PERIOD, data);

	return 0;
}

/*
 * Uploads the part of an effect setting the shape of the force
 */

static int make_shape_modifier(struct iforce* iforce, struct resource* mod_chunk,
	u16 attack_duration, __s16 initial_level,
	u16 fade_duration, __s16 final_level)
{
	unsigned char data[8];

	attack_duration = TIME_SCALE(attack_duration);
	fade_duration = TIME_SCALE(fade_duration);

	if (allocate_resource(&(iforce->device_memory), mod_chunk, 0x0e,
		iforce->device_memory.start, iforce->device_memory.end, 2L,
		NULL, NULL)) {
		return -ENOMEM;
	}

	data[0] = LO(mod_chunk->start);
	data[1] = HI(mod_chunk->start);

	data[2] = LO(attack_duration);
	data[3] = HI(attack_duration);
	data[4] = HI(initial_level);

	data[5] = LO(fade_duration);
	data[6] = HI(fade_duration);
	data[7] = HI(final_level);

	send_packet(iforce, FF_CMD_SHAPE, data);

	return 0;
}

/*
 * Component of spring, friction, inertia... effects
 */

static int make_interactive_modifier(struct iforce* iforce,
	struct resource* mod_chunk,
	__s16 rsat, __s16 lsat, __s16 rk, __s16 lk, u16 db, __s16 center)
{
	unsigned char data[10];

	if (allocate_resource(&(iforce->device_memory), mod_chunk, 8,
		iforce->device_memory.start, iforce->device_memory.end, 2L,
		NULL, NULL)) {
		return -ENOMEM;
	}

	data[0] = LO(mod_chunk->start);
	data[1] = HI(mod_chunk->start);

	data[2] = HI(rk);
	data[3] = HI(lk);

	data[4] = LO(center);
	data[5] = HI(center);

	data[6] = LO(db);
	data[7] = HI(db);

	data[8] = HI(rsat);
	data[9] = HI(lsat);

	send_packet(iforce, FF_CMD_INTERACT, data);

	return 0;
}

static unsigned char find_button(struct iforce *iforce, signed short button)
{
	int i;
	for (i = 1; iforce->type->btn[i] >= 0; i++)
		if (iforce->type->btn[i] == button)
			return i + 1;
	return 0;
}

/*
 * Send the part common to all effects to the device
 */

static int make_core(struct iforce* iforce, u16 id, u16 mod_id1, u16 mod_id2,
	u8 effect_type, u8 axes, u16 duration, u16 delay, u16 button,
	u16 interval, u16 direction)
{
	unsigned char data[14];

	duration = TIME_SCALE(duration);
	delay    = TIME_SCALE(delay);
	interval = TIME_SCALE(interval);

	data[0]  = LO(id);
	data[1]  = effect_type;
	data[2]  = LO(axes) | find_button(iforce, button);

	data[3]  = LO(duration);
	data[4]  = HI(duration);

	data[5]  = HI(direction);

	data[6]  = LO(interval);
	data[7]  = HI(interval);

	data[8]  = LO(mod_id1);
	data[9]  = HI(mod_id1);
	data[10] = LO(mod_id2);
	data[11] = HI(mod_id2);

	data[12] = LO(delay);
	data[13] = HI(delay);

	send_packet(iforce, FF_CMD_EFFECT, data);

	return 0;
}

/*
 * Upload a periodic effect to the device
 */

static int iforce_upload_periodic(struct iforce* iforce, struct ff_effect* effect)
{
	u8 wave_code;
	int core_id = effect->id;
	struct iforce_core_effect* core_effect = iforce->core_effects + core_id;
	struct resource* mod1_chunk = &(iforce->core_effects[core_id].mod1_chunk);
	struct resource* mod2_chunk = &(iforce->core_effects[core_id].mod2_chunk);
	int err = 0;

	err = make_period_modifier(iforce, mod1_chunk,
		effect->u.periodic.magnitude, effect->u.periodic.offset,
		effect->u.periodic.period, effect->u.periodic.phase);
	if (err) return err;
	set_bit(FF_MOD1_IS_USED, core_effect->flags);

	err = make_shape_modifier(iforce, mod2_chunk,
		effect->u.periodic.shape.attack_length,
		effect->u.periodic.shape.attack_level,
		effect->u.periodic.shape.fade_length,
		effect->u.periodic.shape.fade_level);
	if (err) return err;
	set_bit(FF_MOD2_IS_USED, core_effect->flags);

	switch (effect->u.periodic.waveform) {
		case FF_SQUARE:		wave_code = 0x20; break;
		case FF_TRIANGLE:	wave_code = 0x21; break;
		case FF_SINE:		wave_code = 0x22; break;
		case FF_SAW_UP:		wave_code = 0x23; break;
		case FF_SAW_DOWN:	wave_code = 0x24; break;
		default:		wave_code = 0x20; break;
	}

	err = make_core(iforce, effect->id,
		mod1_chunk->start,
		mod2_chunk->start,
		wave_code,
		0x20,
		effect->replay.length,
		effect->replay.delay,
		effect->trigger.button,
		effect->trigger.interval,
		effect->u.periodic.direction);

	return err;
}

/*
 * Upload a constant force effect
 */
static int iforce_upload_constant(struct iforce* iforce, struct ff_effect* effect)
{
	int core_id = effect->id;
	struct iforce_core_effect* core_effect = iforce->core_effects + core_id;
	struct resource* mod1_chunk = &(iforce->core_effects[core_id].mod1_chunk);
	struct resource* mod2_chunk = &(iforce->core_effects[core_id].mod2_chunk);
	int err = 0;

	printk(KERN_DEBUG "iforce.c: make constant effect\n");

	err = make_magnitude_modifier(iforce, mod1_chunk, effect->u.constant.level);
	if (err) return err;
	set_bit(FF_MOD1_IS_USED, core_effect->flags);

	err = make_shape_modifier(iforce, mod2_chunk,
		effect->u.constant.shape.attack_length,
		effect->u.constant.shape.attack_level,
		effect->u.constant.shape.fade_length,
		effect->u.constant.shape.fade_level);
	if (err) return err;
	set_bit(FF_MOD2_IS_USED, core_effect->flags);

	err = make_core(iforce, effect->id,
		mod1_chunk->start,
		mod2_chunk->start,
		0x00,
		0x20,
		effect->replay.length,
		effect->replay.delay,
		effect->trigger.button,
		effect->trigger.interval,
		effect->u.constant.direction);

	return err;
}

/*
 * Upload an interactive effect. Those are for example friction, inertia, springs...
 */
static int iforce_upload_interactive(struct iforce* iforce, struct ff_effect* effect)
{
	int core_id = effect->id;
	struct iforce_core_effect* core_effect = iforce->core_effects + core_id;
	struct resource* mod_chunk = &(core_effect->mod1_chunk);
	u8 type, axes;
	u16 mod1, mod2, direction;
	int err = 0;

	printk(KERN_DEBUG "iforce.c: make interactive effect\n");

	switch (effect->type) {
		case FF_SPRING:		type = 0x40; break;
		case FF_FRICTION:	type = 0x41; break;
		default: return -1;
	}

	err = make_interactive_modifier(iforce, mod_chunk,
		effect->u.interactive.right_saturation,
		effect->u.interactive.left_saturation,
		effect->u.interactive.right_coeff,
		effect->u.interactive.left_coeff,
		effect->u.interactive.deadband,
		effect->u.interactive.center);
	if (err) return err;
	set_bit(FF_MOD1_IS_USED, core_effect->flags);

	switch ((test_bit(ABS_X, &effect->u.interactive.axis) ||
		test_bit(ABS_WHEEL, &effect->u.interactive.axis)) |
		(!!test_bit(ABS_Y, &effect->u.interactive.axis) << 1)) {

		case 0: /* Only one axis, choose orientation */
			mod1 = mod_chunk->start;
			mod2 = 0xffff;
			direction = effect->u.interactive.direction;
			axes = 0x20;
			break;

		case 1:	/* Only X axis */
			mod1 = mod_chunk->start;
			mod2 = 0xffff;
			direction = 0x5a00;
			axes = 0x40;
			break;

		case 2: /* Only Y axis */
			mod1 = 0xffff;
			mod2 = mod_chunk->start;
			direction = 0xb400;
			axes = 0x80;
			break;

		case 3:	/* Both X and Y axes */
			/* TODO: same setting for both axes is not mandatory */
			mod1 = mod_chunk->start;
			mod2 = mod_chunk->start;
			direction = 0x6000;
			axes = 0xc0;
			break;

		default:
			return -1;
	}

	err = make_core(iforce, effect->id,
		mod1, mod2,
		type, axes,
		effect->replay.length, effect->replay.delay,
		effect->trigger.button, effect->trigger.interval,
		direction);

	return err;
}

/*
 * Function called when an ioctl is performed on the event dev entry.
 * It uploads an effect to the device
 */
static int iforce_upload_effect(struct input_dev *dev, struct ff_effect *effect)
{
	struct iforce* iforce = (struct iforce*)(dev->private);
	int id;

	printk(KERN_DEBUG "iforce.c: upload effect\n");

/*
 * Get a free id
 */

	for (id=0; id < FF_EFFECTS_MAX; ++id)
		if (!test_bit(FF_CORE_IS_USED, iforce->core_effects[id].flags)) break;

	if ( id == FF_EFFECTS_MAX || id >= iforce->dev.ff_effects_max)
		return -ENOMEM;

	effect->id = id;
	set_bit(FF_CORE_IS_USED, iforce->core_effects[id].flags);

/*
 * Upload the effect
 */

	switch (effect->type) {

		case FF_PERIODIC:
			return iforce_upload_periodic(iforce, effect);

		case FF_CONSTANT:
			return iforce_upload_constant(iforce, effect);

		case FF_SPRING:
		case FF_FRICTION:
			return iforce_upload_interactive(iforce, effect);

		default:
			return -1;
	}
}

/*
 * Erases an effect: it frees the effect id and mark as unused the memory
 * allocated for the parameters
 */
static int iforce_erase_effect(struct input_dev *dev, int effect_id)
{
	struct iforce* iforce = (struct iforce*)(dev->private);
	int err = 0;
	struct iforce_core_effect* core_effect;

	printk(KERN_DEBUG "iforce.c: erase effect %d\n", effect_id);

	if (effect_id < 0 || effect_id >= FF_EFFECTS_MAX)
		return -EINVAL;

	core_effect = iforce->core_effects + effect_id;

	if (test_bit(FF_MOD1_IS_USED, core_effect->flags))
		err = release_resource(&(iforce->core_effects[effect_id].mod1_chunk));

	if (!err && test_bit(FF_MOD2_IS_USED, core_effect->flags))
		err = release_resource(&(iforce->core_effects[effect_id].mod2_chunk));

	/*TODO: remember to change that if more FF_MOD* bits are added */
	core_effect->flags[0] = 0;

	return err;
}
static int iforce_init_device(struct iforce *iforce)
{
	unsigned char c[] = "CEOV";
	int i;

	init_waitqueue_head(&iforce->wait);
	iforce->dev.ff_effects_max = 10;

/*
 * Input device fields.
 */

	iforce->dev.idbus = BUS_USB;
	iforce->dev.private = iforce;
	iforce->dev.name = iforce->name;
	iforce->dev.open = iforce_open;
	iforce->dev.close = iforce_close;
	iforce->dev.event = iforce_input_event;
	iforce->dev.upload_effect = iforce_upload_effect;
	iforce->dev.erase_effect = iforce_erase_effect;

/*
 * On-device memory allocation.
 */

	iforce->device_memory.name = "I-Force device effect memory";
	iforce->device_memory.start = 0;
	iforce->device_memory.end = 200;
	iforce->device_memory.flags = IORESOURCE_MEM;
	iforce->device_memory.parent = NULL;
	iforce->device_memory.child = NULL;
	iforce->device_memory.sibling = NULL;

/*
 * Wait until device ready - until it sends its first response.
 */

	for (i = 0; i < 20; i++)
		if (!get_id_packet(iforce, "O"))
			break;

	if (i == 20) { /* 5 seconds */
		printk(KERN_ERR "iforce.c: Timeout waiting for response from device.\n");
		iforce_close(&iforce->dev);
		return -1;
	}

/*
 * Get device info.
 */

	if (!get_id_packet(iforce, "M"))
		iforce->dev.idvendor = (iforce->edata[2] << 8) | iforce->edata[1];
	if (!get_id_packet(iforce, "P"))
		iforce->dev.idproduct = (iforce->edata[2] << 8) | iforce->edata[1];
	if (!get_id_packet(iforce, "B"))
		iforce->device_memory.end = (iforce->edata[2] << 8) | iforce->edata[1];
	if (!get_id_packet(iforce, "N"))
		iforce->dev.ff_effects_max = iforce->edata[1];

/*
 * Display additional info.
 */

	for (i = 0; c[i]; i++)
		if (!get_id_packet(iforce, c + i))
			dump_packet("info", iforce->ecmd, iforce->edata);

/*
 * Disable spring, enable force feedback.
 * FIXME: We should use iforce_set_autocenter() et al here.
 */

	send_packet(iforce, FF_CMD_AUTOCENTER, "\004\000");
	send_packet(iforce, FF_CMD_ENABLE, "\004");

/*
 * Find appropriate device entry
 */

	for (i = 0; iforce_device[i].idvendor; i++)
		if (iforce_device[i].idvendor == iforce->dev.idvendor &&
		    iforce_device[i].idproduct == iforce->dev.idproduct)
			break;

	iforce->type = iforce_device + i;

	sprintf(iforce->name, iforce->type->name,
		iforce->dev.idproduct, iforce->dev.idvendor);

/*
 * Set input device bitfields and ranges.
 */

	iforce->dev.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS) | BIT(EV_FF);

	for (i = 0; iforce->type->btn[i] >= 0; i++) {
		signed short t = iforce->type->btn[i];
		set_bit(t, iforce->dev.keybit);
		if (t != BTN_DEAD)
			set_bit(FF_BTN(t), iforce->dev.ffbit);
	}

	for (i = 0; iforce->type->abs[i] >= 0; i++) {

		signed short t = iforce->type->abs[i];
		set_bit(t, iforce->dev.absbit);

		switch (t) {

			case ABS_X:
			case ABS_Y:
			case ABS_WHEEL:

				iforce->dev.absmax[t] =  1920;
				iforce->dev.absmin[t] = -1920;
				iforce->dev.absflat[t] = 128;
				iforce->dev.absfuzz[t] = 16;

				set_bit(FF_ABS(t), iforce->dev.ffbit);
				break;

			case ABS_THROTTLE:
			case ABS_GAS:
			case ABS_BRAKE:

				iforce->dev.absmax[t] = 255;
				iforce->dev.absmin[t] = 0;
				break;

			case ABS_HAT0X:
			case ABS_HAT0Y:
				iforce->dev.absmax[t] =  1;
				iforce->dev.absmin[t] = -1;
				break;
		}
	}

	for (i = 0; iforce->type->ff[i] >= 0; i++)
		set_bit(iforce->type->ff[i], iforce->dev.ffbit);

/*
 * Register input device.
 */

	input_register_device(&iforce->dev);

	return 0;
}

#ifdef IFORCE_USB

static void iforce_usb_irq(struct urb *urb)
{
	struct iforce *iforce = urb->context;
	if (urb->status) return;
	iforce_process_packet(iforce,
		(iforce->data[0] << 8) | (urb->actual_length - 1), iforce->data + 1);
}

static void iforce_usb_out(struct urb *urb)
{
	struct iforce *iforce = urb->context;
	if (urb->status) return;
	if (waitqueue_active(&iforce->wait))
		wake_up(&iforce->wait);
}

static void iforce_usb_ctrl(struct urb *urb)
{
	struct iforce *iforce = urb->context;
	if (urb->status) return;
	iforce->ecmd = 0xff00 | urb->actual_length;
	if (waitqueue_active(&iforce->wait))
		wake_up(&iforce->wait);
}

static void *iforce_usb_probe(struct usb_device *dev, unsigned int ifnum,
				const struct usb_device_id *id)
{
	struct usb_endpoint_descriptor *epirq, *epout;
	struct iforce *iforce;

	epirq = dev->config[0].interface[ifnum].altsetting[0].endpoint + 0;
	epout = dev->config[0].interface[ifnum].altsetting[0].endpoint + 1;

	if (!(iforce = kmalloc(sizeof(struct iforce) + 32, GFP_KERNEL))) return NULL;
	memset(iforce, 0, sizeof(struct iforce));

	iforce->bus = IFORCE_USB;
	iforce->usbdev = dev;

	iforce->dr.requesttype = USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_INTERFACE;
	iforce->dr.index = 0;
	iforce->dr.length = 16;

	FILL_INT_URB(&iforce->irq, dev, usb_rcvintpipe(dev, epirq->bEndpointAddress),
			iforce->data, 16, iforce_usb_irq, iforce, epirq->bInterval);

	FILL_BULK_URB(&iforce->out, dev, usb_sndbulkpipe(dev, epout->bEndpointAddress),
			iforce + 1, 32, iforce_usb_out, iforce);

	FILL_CONTROL_URB(&iforce->ctrl, dev, usb_rcvctrlpipe(dev, 0),
			(void*) &iforce->dr, iforce->edata, 16, iforce_usb_ctrl, iforce);

	if (iforce_init_device(iforce)) {
		kfree(iforce);
		return NULL;
	}

	printk(KERN_INFO "input%d: %s [%d effects, %ld bytes memory] on usb%d:%d.%d\n",
		iforce->dev.number, iforce->dev.name, iforce->dev.ff_effects_max,
		iforce->device_memory.end, dev->bus->busnum, dev->devnum, ifnum);

	return iforce;
}

static void iforce_usb_disconnect(struct usb_device *dev, void *ptr)
{
	struct iforce *iforce = ptr;
	usb_unlink_urb(&iforce->irq);
	input_unregister_device(&iforce->dev);
	kfree(iforce);
}

static struct usb_device_id iforce_usb_ids [] = {
	{ USB_DEVICE(0x046d, 0xc281) },		/* Logitech WingMan Force */
	{ USB_DEVICE(0x046d, 0xc291) },		/* Logitech WingMan Formula Force */
	{ USB_DEVICE(0x05ef, 0x020a) },		/* AVB Top Shot Pegasus */
	{ USB_DEVICE(0x05ef, 0x8884) },		/* AVB Mag Turbo Force */
	{ USB_DEVICE(0x06f8, 0x0001) },		/* Guillemot Race Leader Force Feedback */
	{ }					/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, iforce_usb_ids);

static struct usb_driver iforce_usb_driver = {
	name:		"iforce",
	probe:		iforce_usb_probe,
	disconnect:	iforce_usb_disconnect,
	id_table:	iforce_usb_ids,
};

#endif

#ifdef IFORCE_232

static void iforce_serio_irq(struct serio *serio, unsigned char data, unsigned int flags)
{
	struct iforce* iforce = serio->private;

	if (!iforce->pkt) {
		if (data != 0x2b) {
			return;
		}
		iforce->pkt = 1;
		return;
	}

	if (!iforce->id) {
		if (data > 3 && data != 0xff) {
			iforce->pkt = 0;
			return;
		}
		iforce->id = data;
		return;
	}

	if (!iforce->len) {
		if (data > IFORCE_MAX_LENGTH) {
			iforce->pkt = 0;
			iforce->id = 0;
			return;
		}
		iforce->len = data;
		return;
	}

	if (iforce->idx < iforce->len) {
		iforce->csum += iforce->data[iforce->idx++] = data;
		return;
	}

	if (iforce->idx == iforce->len) {
		iforce_process_packet(iforce, (iforce->id << 8) | iforce->idx, iforce->data);
		iforce->pkt = 0;
		iforce->id  = 0;
		iforce->len = 0;
		iforce->idx = 0;
		iforce->csum = 0;
	}
}

static void iforce_serio_connect(struct serio *serio, struct serio_dev *dev)
{
	struct iforce *iforce;
	if (serio->type != (SERIO_RS232 | SERIO_IFORCE))
		return;

	if (!(iforce = kmalloc(sizeof(struct iforce), GFP_KERNEL))) return;
	memset(iforce, 0, sizeof(struct iforce));

	iforce->bus = IFORCE_232;
	iforce->serio = serio;
	serio->private = iforce;

	if (serio_open(serio, dev)) {
		kfree(iforce);
		return;
	}

	if (iforce_init_device(iforce)) {
		serio_close(serio);
		kfree(iforce);
		return;
	}

	printk(KERN_INFO "input%d: %s [%d effects, %ld bytes memory] on serio%d\n",
		iforce->dev.number, iforce->dev.name, iforce->dev.ff_effects_max,
		iforce->device_memory.end, serio->number);
}

static void iforce_serio_disconnect(struct serio *serio)
{
	struct iforce* iforce = serio->private;

	input_unregister_device(&iforce->dev);
	serio_close(serio);
	kfree(iforce);
}

static struct serio_dev iforce_serio_dev = {
	interrupt:	iforce_serio_irq,
	connect:	iforce_serio_connect,
	disconnect:	iforce_serio_disconnect,
};

#endif

static int __init iforce_init(void)
{
#ifdef IFORCE_USB
	usb_register(&iforce_usb_driver);
#endif
#ifdef IFORCE_232
	serio_register_device(&iforce_serio_dev);
#endif
	return 0;
}

static void __exit iforce_exit(void)
{
#ifdef IFORCE_USB
	usb_deregister(&iforce_usb_driver);
#endif
#ifdef IFORCE_232
	serio_unregister_device(&iforce_serio_dev);
#endif
}

module_init(iforce_init);
module_exit(iforce_exit);