grip_mp.c

h内核

/*
 * $Id: grip_mp.c,v 1.9 2002/07/20 19:28:45 bonnland Exp $
 *
 *  Driver for the Gravis Grip Multiport, a gamepad "hub" that
 *  connects up to four 9-pin digital gamepads/joysticks.
 *  Driver tested on SMP and UP kernel versions 2.4.18-4 and 2.4.18-5.
 *
 *  Thanks to Chris Gassib for helpful advice.
 *
 *  Copyright (c)      2002 Brian Bonnlander, Bill Soudan
 *  Copyright (c) 1998-2000 Vojtech Pavlik
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/gameport.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>

MODULE_AUTHOR("Brian Bonnlander");
MODULE_DESCRIPTION("Gravis Grip Multiport driver");
MODULE_LICENSE("GPL");

#ifdef GRIP_DEBUG
#define dbg(format, arg...) printk(KERN_ERR __FILE__ ": " format "\n" , ## arg)
#else
#define dbg(format, arg...) do {} while (0)
#endif

/*
 * Grip multiport state
 */

struct grip_mp {
	struct gameport *gameport;
	struct timer_list timer;
	struct input_dev dev[4];
	int mode[4];
	int registered[4];
	int used;
	int reads;
	int bads;

	/* individual gamepad states */
	int buttons[4];
	int xaxes[4];
	int yaxes[4];
	int dirty[4];     /* has the state been updated? */
};

/*
 * Multiport packet interpretation
 */

#define PACKET_FULL          0x80000000       /* packet is full                        */
#define PACKET_IO_FAST       0x40000000       /* 3 bits per gameport read              */
#define PACKET_IO_SLOW       0x20000000       /* 1 bit per gameport read               */
#define PACKET_MP_MORE       0x04000000       /* multiport wants to send more          */
#define PACKET_MP_DONE       0x02000000       /* multiport done sending                */

/*
 * Packet status code interpretation
 */

#define IO_GOT_PACKET        0x0100           /* Got a packet                           */
#define IO_MODE_FAST         0x0200           /* Used 3 data bits per gameport read     */
#define IO_SLOT_CHANGE       0x0800           /* Multiport physical slot status changed */
#define IO_DONE              0x1000           /* Multiport is done sending packets      */
#define IO_RETRY             0x4000           /* Try again later to get packet          */
#define IO_RESET             0x8000           /* Force multiport to resend all packets  */

/*
 * Gamepad configuration data.  Other 9-pin digital joystick devices
 * may work with the multiport, so this may not be an exhaustive list!
 * Commodore 64 joystick remains untested.
 */

#define GRIP_INIT_DELAY         2000          /*  2 ms */
#define GRIP_REFRESH_TIME       HZ/50	      /* 20 ms */

#define GRIP_MODE_NONE		0
#define GRIP_MODE_RESET         1
#define GRIP_MODE_GP		2
#define GRIP_MODE_C64		3

static int grip_btn_gp[]  = { BTN_TR, BTN_TL, BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, -1 };
static int grip_btn_c64[] = { BTN_JOYSTICK, -1 };

static int grip_abs_gp[]  = { ABS_X, ABS_Y, -1 };
static int grip_abs_c64[] = { ABS_X, ABS_Y, -1 };

static int *grip_abs[] = { NULL, NULL, grip_abs_gp, grip_abs_c64 };
static int *grip_btn[] = { NULL, NULL, grip_btn_gp, grip_btn_c64 };

static char *grip_name[] = { NULL, NULL, "Gravis Grip Pad", "Commodore 64 Joystick" };

static const int init_seq[] = {
	1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1,
	1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
	1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1,
	0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1 };

/* Maps multiport directional values to X,Y axis values (each axis encoded in 3 bits) */

static int axis_map[] = { 5, 9, 1, 5, 6, 10, 2, 6, 4, 8, 0, 4, 5, 9, 1, 5 };

static void register_slot(int i, struct grip_mp *grip);

/*
 * Returns whether an odd or even number of bits are on in pkt.
 */

static int bit_parity(u32 pkt)
{
	int x = pkt ^ (pkt >> 16);
	x ^= x >> 8;
	x ^= x >> 4;
	x ^= x >> 2;
	x ^= x >> 1;
	return x & 1;
}

/*
 * Poll gameport; return true if all bits set in 'onbits' are on and
 * all bits set in 'offbits' are off.
 */

static inline int poll_until(u8 onbits, u8 offbits, int u_sec, struct gameport* gp, u8 *data)
{
	int i, nloops;

	nloops = gameport_time(gp, u_sec);
	for (i = 0; i < nloops; i++) {
		*data = gameport_read(gp);
		if ((*data & onbits) == onbits &&
		    (~(*data) & offbits) == offbits)
			return 1;
	}
	dbg("gameport timed out after %d microseconds.\n", u_sec);
	return 0;
}

/*
 * Gets a 28-bit packet from the multiport.
 *
 * After getting a packet successfully, commands encoded by sendcode may
 * be sent to the multiport.
 *
 * The multiport clock value is reflected in gameport bit B4.
 *
 * Returns a packet status code indicating whether packet is valid, the transfer
 * mode, and any error conditions.
 *
 * sendflags:      current I/O status
 * sendcode:   data to send to the multiport if sendflags is nonzero
 */

static int mp_io(struct gameport* gameport, int sendflags, int sendcode, u32 *packet)
{
	u8  raw_data;            /* raw data from gameport */
	u8  data_mask;           /* packet data bits from raw_data */
	u32 pkt;                 /* packet temporary storage */
	int bits_per_read;       /* num packet bits per gameport read */
	int portvals = 0;        /* used for port value sanity check */
	int i;

	/* Gameport bits B0, B4, B5 should first be off, then B4 should come on. */

	*packet = 0;
	raw_data = gameport_read(gameport);
	if (raw_data & 1)
 		return IO_RETRY;

	for (i = 0; i < 64; i++) {
		raw_data = gameport_read(gameport);
		portvals |= 1 << ((raw_data >> 4) & 3); /* Demux B4, B5 */
	}

	if (portvals == 1) {                            /* B4, B5 off */
		raw_data = gameport_read(gameport);
		portvals = raw_data & 0xf0;

		if (raw_data & 0x31)
			return IO_RESET;
		gameport_trigger(gameport);

		if (!poll_until(0x10, 0, 308, gameport, &raw_data))
			return IO_RESET;
	} else
		return IO_RETRY;

	/* Determine packet transfer mode and prepare for packet construction. */

	if (raw_data & 0x20) {                 /* 3 data bits/read */
		portvals |= raw_data >> 4;     /* Compare B4-B7 before & after trigger */

		if (portvals != 0xb)
			return 0;
		data_mask = 7;
		bits_per_read = 3;
		pkt = (PACKET_FULL | PACKET_IO_FAST) >> 28;
	} else {                                 /* 1 data bit/read */
		data_mask = 1;
		bits_per_read = 1;
		pkt = (PACKET_FULL | PACKET_IO_SLOW) >> 28;
	}

	/* Construct a packet.  Final data bits must be zero. */

	while (1) {
		if (!poll_until(0, 0x10, 77, gameport, &raw_data))
			return IO_RESET;
		raw_data = (raw_data >> 5) & data_mask;

		if (pkt & PACKET_FULL)
			break;
		pkt = (pkt << bits_per_read) | raw_data;

		if (!poll_until(0x10, 0, 77, gameport, &raw_data))
			return IO_RESET;
	}

	if (raw_data)
		return IO_RESET;

	/* If 3 bits/read used, drop from 30 bits to 28. */

	if (bits_per_read == 3) {
		pkt = (pkt & 0xffff0000) | ((pkt << 1) & 0xffff);
		pkt = (pkt >> 2) | 0xf0000000;
	}

	if (bit_parity(pkt) == 1)
		return IO_RESET;

	/* Acknowledge packet receipt */

	if (!poll_until(0x30, 0, 77, gameport, &raw_data))
		return IO_RESET;

	raw_data = gameport_read(gameport);

	if (raw_data & 1)
		return IO_RESET;

	gameport_trigger(gameport);

	if (!poll_until(0, 0x20, 77, gameport, &raw_data))
		return IO_RESET;

        /* Return if we just wanted the packet or multiport wants to send more */

	*packet = pkt;
	if ((sendflags == 0) || ((sendflags & IO_RETRY) && !(pkt & PACKET_MP_DONE)))
		return IO_GOT_PACKET;

	if (pkt & PACKET_MP_MORE)
		return IO_GOT_PACKET | IO_RETRY;

	/* Multiport is done sending packets and is ready to receive data */

	if (!poll_until(0x20, 0, 77, gameport, &raw_data))
		return IO_GOT_PACKET | IO_RESET;

	raw_data = gameport_read(gameport);
	if (raw_data & 1)
		return IO_GOT_PACKET | IO_RESET;

	/* Trigger gameport based on bits in sendcode */

	gameport_trigger(gameport);
	do {
		if (!poll_until(0x20, 0x10, 116, gameport, &raw_data))
			return IO_GOT_PACKET | IO_RESET;

		if (!poll_until(0x30, 0, 193, gameport, &raw_data))
			return IO_GOT_PACKET | IO_RESET;

		if (raw_data & 1)
			return IO_GOT_PACKET | IO_RESET;

		if (sendcode & 1)
			gameport_trigger(gameport);

		sendcode >>= 1;
	} while (sendcode);

	return IO_GOT_PACKET | IO_MODE_FAST;
}

/*
 * Disables and restores interrupts for mp_io(), which does the actual I/O.
 */

static int multiport_io(struct gameport* gameport, int sendflags, int sendcode, u32 *packet)
{
	int status;
	unsigned long flags;

	local_irq_save(flags);
	status = mp_io(gameport, sendflags, sendcode, packet);
	local_irq_restore(flags);

	return status;
}

/*
 * Puts multiport into digital mode.  Multiport LED turns green.
 *
 * Returns true if a valid digital packet was received, false otherwise.
 */

static int dig_mode_start(struct gameport *gameport, u32 *packet)
{
	int i, seq_len = sizeof(init_seq)/sizeof(int);
	int flags, tries = 0, bads = 0;

	for (i = 0; i < seq_len; i++) {     /* Send magic sequence */
		if (init_seq[i])
			gameport_trigger(gameport);
		udelay(GRIP_INIT_DELAY);
	}

	for (i = 0; i < 16; i++)            /* Wait for multiport to settle */
		udelay(GRIP_INIT_DELAY);

	while (tries < 64 && bads < 8) {    /* Reset multiport and try getting a packet */

		flags = multiport_io(gameport, IO_RESET, 0x27, packet);

		if (flags & IO_MODE_FAST)
			return 1;

		if (flags & IO_RETRY)
			tries++;