/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 *  Copyright (c) 2000-2002 Vojtech Pavlik <vojtech@ucw.cz>
 *  Copyright (c) 2001-2002, 2007 Johann Deneux <johann.deneux@gmail.com>
 *
 *  USB/RS232 I-Force joysticks and wheels.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/circ_buf.h>
#include <linux/mutex.h>

/* 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>


#define IFORCE_MAX_LENGTH	16

#define IFORCE_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	/* Effect is currently being played */
#define FF_CORE_SHOULD_PLAY	4	/* User wants the effect to be played */
#define FF_CORE_UPDATE		5	/* Effect is being updated */
#define FF_MODCORE_CNT		6

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[BITS_TO_LONGS(FF_MODCORE_CNT)];
};

#define FF_CMD_EFFECT		0x010e
#define FF_CMD_ENVELOPE		0x0208
#define FF_CMD_MAGNITUDE	0x0303
#define FF_CMD_PERIOD		0x0407
#define FF_CMD_CONDITION	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

/* Buffer for async write */
#define XMIT_SIZE		256
#define XMIT_INC(var, n)	(var)+=n; (var)&= XMIT_SIZE -1
/* iforce::xmit_flags */
#define IFORCE_XMIT_RUNNING	0
#define IFORCE_XMIT_AGAIN	1

struct iforce_device {
	u16 idvendor;
	u16 idproduct;
	char *name;
	signed short *btn;
	signed short *abs;
	signed short *ff;
};

struct iforce;

struct iforce_xport_ops {
	void (*xmit)(struct iforce *iforce);
	int (*get_id)(struct iforce *iforce, u8 id,
		      u8 *response_data, size_t *response_len);
	int (*start_io)(struct iforce *iforce);
	void (*stop_io)(struct iforce *iforce);
};

struct iforce {
	struct input_dev *dev;		/* Input device interface */
	struct iforce_device *type;
	const struct iforce_xport_ops *xport_ops;

	spinlock_t xmit_lock;
	/* Buffer used for asynchronous sending of bytes to the device */
	struct circ_buf xmit;
	unsigned char xmit_data[XMIT_SIZE];
	unsigned long xmit_flags[1];

					/* Force Feedback */
	wait_queue_head_t wait;
	struct resource device_memory;
	struct iforce_core_effect core_effects[IFORCE_EFFECTS_MAX];
	struct mutex mem_mutex;
};

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

/* For many parameters, it seems that 0x80 is a special value that should
 * be avoided. Instead, we replace this value by 0x7f
 */
#define HIFIX80(a) ((unsigned char)(((a)<0? (a)+255 : (a))>>8))

/* Encode a time value */
#define TIME_SCALE(a)	(a)

static inline int iforce_get_id_packet(struct iforce *iforce, u8 id,
				       u8 *response_data, size_t *response_len)
{
	return iforce->xport_ops->get_id(iforce, id,
					 response_data, response_len);
}

static inline void iforce_clear_xmit_and_wake(struct iforce *iforce)
{
	clear_bit(IFORCE_XMIT_RUNNING, iforce->xmit_flags);
	wake_up_all(&iforce->wait);
}

/* Public functions */
/* iforce-main.c */
int iforce_init_device(struct device *parent, u16 bustype,
		       struct iforce *iforce);

/* iforce-packets.c */
int iforce_control_playback(struct iforce*, u16 id, unsigned int);
void iforce_process_packet(struct iforce *iforce,
			   u8 packet_id, u8 *data, size_t len);
int iforce_send_packet(struct iforce *iforce, u16 cmd, unsigned char* data);
void iforce_dump_packet(struct iforce *iforce, char *msg, u16 cmd, unsigned char *data);

/* iforce-ff.c */
int iforce_upload_periodic(struct iforce *, struct ff_effect *, struct ff_effect *);
int iforce_upload_constant(struct iforce *, struct ff_effect *, struct ff_effect *);
int iforce_upload_condition(struct iforce *, struct ff_effect *, struct ff_effect *);

/* Public variables */
extern struct serio_driver iforce_serio_drv;
extern struct usb_driver iforce_usb_driver