stir4200.c

《linux驱动程序设计从入门到精通》一书中所有的程序代码含驱动和相应的应用程序

/*****************************************************************************
*
* Filename:      stir4200.c
* Version:       0.4
* Description:   Irda SigmaTel USB Dongle
* Status:        Experimental
* Author:        Stephen Hemminger <[e-mail]>
*
*  	Based on earlier driver by Paul Stewart <[e-mail]>
*
*	Copyright (C) 2000, Roman Weissgaerber <[e-mail]>
*	Copyright (C) 2001, Dag Brattli <[e-mail]>
*	Copyright (C) 2001, Jean Tourrilhes <[e-mail]>
*	Copyright (C) 2004, Stephen Hemminger <[e-mail]>
*
*	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.
*
*	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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*****************************************************************************/

/*
 * This dongle does no framing, and requires polling to receive the
 * data.  The STIr4200 has bulk in and out endpoints just like
 * usr-irda devices, but the data it sends and receives is raw; like
 * irtty, it needs to call the wrap and unwrap functions to add and
 * remove SOF/BOF and escape characters to/from the frame.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/usb.h>
#include <linux/crc32.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <net/irda/irda.h>
#include <net/irda/irlap.h>
#include <net/irda/irda_device.h>
#include <net/irda/wrapper.h>
#include <net/irda/crc.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>

MODULE_AUTHOR("Stephen Hemminger <[e-mail]>");
MODULE_DESCRIPTION("IrDA-USB Dongle Driver for SigmaTel STIr4200");
MODULE_LICENSE("GPL");

static int qos_mtt_bits = 0x07;	/* 1 ms or more */
module_param(qos_mtt_bits, int, 0);
MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");

static int rx_sensitivity = 1;	/* FIR 0..4, SIR 0..6 */
module_param(rx_sensitivity, int, 0);
MODULE_PARM_DESC(rx_sensitivity, "Set Receiver sensitivity (0-6, 0 is most sensitive)");

static int tx_power = 0;	/* 0 = highest ... 3 = lowest */
module_param(tx_power, int, 0);
MODULE_PARM_DESC(tx_power, "Set Transmitter power (0-3, 0 is highest power)");

#define STIR_IRDA_HEADER  	4
#define CTRL_TIMEOUT		100	   /* milliseconds */
#define TRANSMIT_TIMEOUT	200	   /* milliseconds */
#define STIR_FIFO_SIZE		4096
#define FIFO_REGS_SIZE		3

enum FirChars {
	FIR_CE   = 0x7d,
	FIR_XBOF = 0x7f,
	FIR_EOF  = 0x7e,
};

enum StirRequests {
	REQ_WRITE_REG =		0x00,
	REQ_READ_REG =		0x01,
	REQ_READ_ROM =		0x02,
	REQ_WRITE_SINGLE =	0x03,
};

/* Register offsets */
enum StirRegs {
	REG_RSVD=0,
	REG_MODE,
	REG_PDCLK,
	REG_CTRL1,
	REG_CTRL2,
	REG_FIFOCTL,
	REG_FIFOLSB,
	REG_FIFOMSB,
	REG_DPLL,
	REG_IRDIG,
	REG_TEST=15,
};

enum StirModeMask {
	MODE_FIR = 0x80,
	MODE_SIR = 0x20,
	MODE_ASK = 0x10,
	MODE_FASTRX = 0x08,
	MODE_FFRSTEN = 0x04,
	MODE_NRESET = 0x02,
	MODE_2400 = 0x01,
};

enum StirPdclkMask {
	PDCLK_4000000 = 0x02,
	PDCLK_115200 = 0x09,
	PDCLK_57600 = 0x13,
	PDCLK_38400 = 0x1D,
	PDCLK_19200 = 0x3B,
	PDCLK_9600 = 0x77,
	PDCLK_2400 = 0xDF,
};

enum StirCtrl1Mask {
	CTRL1_SDMODE = 0x80,
	CTRL1_RXSLOW = 0x40,
	CTRL1_TXPWD = 0x10,
	CTRL1_RXPWD = 0x08,
	CTRL1_SRESET = 0x01,
};

enum StirCtrl2Mask {
	CTRL2_SPWIDTH = 0x08,
	CTRL2_REVID = 0x03,
};

enum StirFifoCtlMask {
	FIFOCTL_EOF = 0x80,
	FIFOCTL_UNDER = 0x40,
	FIFOCTL_OVER = 0x20,
	FIFOCTL_DIR = 0x10,
	FIFOCTL_CLR = 0x08,
	FIFOCTL_EMPTY = 0x04,
};

enum StirDiagMask {
	IRDIG_RXHIGH = 0x80,
	IRDIG_RXLOW = 0x40,
};

enum StirTestMask {
	TEST_PLLDOWN = 0x80,
	TEST_LOOPIR = 0x40,
	TEST_LOOPUSB = 0x20,
	TEST_TSTENA = 0x10,
	TEST_TSTOSC = 0x0F,
};

struct stir_cb {
        struct usb_device *usbdev;      /* init: probe_irda */
        struct net_device *netdev;      /* network layer */
        struct irlap_cb   *irlap;       /* The link layer we are binded to */
        struct net_device_stats stats;	/* network statistics */
        struct qos_info   qos;
	unsigned 	  speed;	/* Current speed */

        struct task_struct *thread;     /* transmit thread */

	struct sk_buff	  *tx_pending;
	void		  *io_buf;	/* transmit/receive buffer */
	__u8		  *fifo_status;

	iobuff_t  	  rx_buff;	/* receive unwrap state machine */
	struct timeval	  rx_time;
	int		  receiving;
	struct urb	 *rx_urb;
};


/* These are the currently known USB ids */
static struct usb_device_id dongles[] = {
    /* SigmaTel, Inc,  STIr4200 IrDA/USB Bridge */
    { USB_DEVICE(0x066f, 0x4200) },
    { }
};

MODULE_DEVICE_TABLE(usb, dongles);

/* Send control message to set dongle register */
static int write_reg(struct stir_cb *stir, __u16 reg, __u8 value)
{
	struct usb_device *dev = stir->usbdev;

	pr_debug("%s: write reg %d = 0x%x\n",
		 stir->netdev->name, reg, value);
	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			       REQ_WRITE_SINGLE,
			       USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_DEVICE,
			       value, reg, NULL, 0,
			       CTRL_TIMEOUT);
}

/* Send control message to read multiple registers */
static inline int read_reg(struct stir_cb *stir, __u16 reg,
		    __u8 *data, __u16 count)
{
	struct usb_device *dev = stir->usbdev;

	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
			       REQ_READ_REG,
			       USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			       0, reg, data, count,
			       CTRL_TIMEOUT);
}

static inline int isfir(u32 speed)
{
	return (speed == 4000000);
}

/*
 * Prepare a FIR IrDA frame for transmission to the USB dongle.  The
 * FIR transmit frame is documented in the datasheet.  It consists of
 * a two byte 0x55 0xAA sequence, two little-endian length bytes, a
 * sequence of exactly 16 XBOF bytes of 0x7E, two BOF bytes of 0x7E,
 * then the data escaped as follows:
 *
 *    0x7D -> 0x7D 0x5D
 *    0x7E -> 0x7D 0x5E
 *    0x7F -> 0x7D 0x5F
 *
 * Then, 4 bytes of little endian (stuffed) FCS follow, then two
 * trailing EOF bytes of 0x7E.
 */
static inline __u8 *stuff_fir(__u8 *p, __u8 c)
{
	switch(c) {
	case 0x7d:
	case 0x7e:
	case 0x7f:
		*p++ = 0x7d;
		c ^= IRDA_TRANS;
		/* fall through */
	default:
		*p++ = c;
	}
	return p;
}

/* Take raw data in skb and put it wrapped into buf */
static unsigned wrap_fir_skb(const struct sk_buff *skb, __u8 *buf)
{
	__u8 *ptr = buf;
	__u32 fcs = ~(crc32_le(~0, skb->data, skb->len));
	__u16 wraplen;
	int i;

	/* Header */
	buf[0] = 0x55;
	buf[1] = 0xAA;

	ptr = buf + STIR_IRDA_HEADER;
	memset(ptr, 0x7f, 16);
	ptr += 16;

	/* BOF */
	*ptr++  = 0x7e;
	*ptr++  = 0x7e;

	/* Address / Control / Information */
	for (i = 0; i < skb->len; i++)
		ptr = stuff_fir(ptr, skb->data[i]);

	/* FCS */
	ptr = stuff_fir(ptr, fcs & 0xff);
	ptr = stuff_fir(ptr, (fcs >> 8) & 0xff);
	ptr = stuff_fir(ptr, (fcs >> 16) & 0xff);
	ptr = stuff_fir(ptr, (fcs >> 24) & 0xff);

	/* EOFs */
	*ptr++ = 0x7e;
	*ptr++ = 0x7e;

	/* Total length, minus the header */
	wraplen = (ptr - buf) - STIR_IRDA_HEADER;
	buf[2] = wraplen & 0xff;
	buf[3] = (wraplen >> 8) & 0xff;

	return wraplen + STIR_IRDA_HEADER;
}

static unsigned wrap_sir_skb(struct sk_buff *skb, __u8 *buf)
{
	__u16 wraplen;

	wraplen = async_wrap_skb(skb, buf + STIR_IRDA_HEADER,
				 STIR_FIFO_SIZE - STIR_IRDA_HEADER);
	buf[0] = 0x55;
	buf[1] = 0xAA;
	buf[2] = wraplen & 0xff;
	buf[3] = (wraplen >> 8) & 0xff;

	return wraplen + STIR_IRDA_HEADER;
}

/*
 * Frame is fully formed in the rx_buff so check crc
 * and pass up to irlap
 * setup for next receive
 */
static void fir_eof(struct stir_cb *stir)
{
	iobuff_t *rx_buff = &stir->rx_buff;
	int len = rx_buff->len - 4;
	struct sk_buff *skb, *nskb;
	__u32 fcs;

	if (unlikely(len <= 0)) {
		pr_debug("%s: short frame len %d\n",
			 stir->netdev->name, len);

		++stir->stats.rx_errors;
		++stir->stats.rx_length_errors;
		return;
	}

	fcs = ~(crc32_le(~0, rx_buff->data, len));
	if (fcs != le32_to_cpu(get_unaligned((u32 *)(rx_buff->data+len)))) {
		pr_debug("crc error calc 0x%x len %d\n", fcs, len);
		stir->stats.rx_errors++;
		stir->stats.rx_crc_errors++;
		return;
	}

	/* if frame is short then just copy it */
	if (len < IRDA_RX_COPY_THRESHOLD) {
		nskb = dev_alloc_skb(len + 1);
		if (unlikely(!nskb)) {
			++stir->stats.rx_dropped;
			return;
		}
		skb_reserve(nskb, 1);
		skb = nskb;
		memcpy(nskb->data, rx_buff->data, len);
	} else {
		nskb = dev_alloc_skb(rx_buff->truesize);
		if (unlikely(!nskb)) {
			++stir->stats.rx_dropped;
			return;
		}
		skb_reserve(nskb, 1);
		skb = rx_buff->skb;
		rx_buff->skb = nskb;
		rx_buff->head = nskb->data;
	}

	skb_put(skb, len);

	skb->mac.raw  = skb->data;
	skb->protocol = htons(ETH_P_IRDA);
	skb->dev = stir->netdev;

	netif_rx(skb);

	stir->stats.rx_packets++;
	stir->stats.rx_bytes += len;

	rx_buff->data = rx_buff->head;
	rx_buff->len = 0;
}

/* Unwrap FIR stuffed data and bump it to IrLAP */
static void stir_fir_chars(struct stir_cb *stir,
			    const __u8 *bytes, int len)
{
	iobuff_t *rx_buff = &stir->rx_buff;
	int	i;

	for (i = 0; i < len; i++) {
		__u8	byte = bytes[i];

		switch(rx_buff->state) {
		case OUTSIDE_FRAME:
			/* ignore garbage till start of frame */
			if (unlikely(byte != FIR_EOF))
				continue;
			/* Now receiving frame */
			rx_buff->state = BEGIN_FRAME;

			/* Time to initialize receive buffer */
			rx_buff->data = rx_buff->head;
			rx_buff->len = 0;
			continue;

		case LINK_ESCAPE:
			if (byte == FIR_EOF) {
				pr_debug("%s: got EOF after escape\n",
					 stir->netdev->name);
				goto frame_error;
			}
			rx_buff->state = INSIDE_FRAME;
			byte ^= IRDA_TRANS;
			break;

		case BEGIN_FRAME:
			/* ignore multiple BOF/EOF */
			if (byte == FIR_EOF)
				continue;
			rx_buff->state = INSIDE_FRAME;
			rx_buff->in_frame = TRUE;

			/* fall through */
		case INSIDE_FRAME:
			switch(byte) {
			case FIR_CE:
				rx_buff->state = LINK_ESCAPE;
				continue;
			case FIR_XBOF:
				/* 0x7f is not used in this framing */
				pr_debug("%s: got XBOF without escape\n",
					 stir->netdev->name);
				goto frame_error;
			case FIR_EOF:
				rx_buff->state = OUTSIDE_FRAME;
				rx_buff->in_frame = FALSE;
				fir_eof(stir);
				continue;
			}
			break;
		}

		/* add byte to rx buffer */
		if (unlikely(rx_buff->len >= rx_buff->truesize)) {
			pr_debug("%s: fir frame exceeds %d\n",
				 stir->netdev->name, rx_buff->truesize);
			++stir->stats.rx_over_errors;
			goto error_recovery;
		}

		rx_buff->data[rx_buff->len++] = byte;
		continue;

	frame_error:
		++stir->stats.rx_frame_errors;

	error_recovery:
		++stir->stats.rx_errors;
		rx_buff->state = OUTSIDE_FRAME;
		rx_buff->in_frame = FALSE;
	}
}

/* Unwrap SIR stuffed data and bump it up to IrLAP */
static void stir_sir_chars(struct stir_cb *stir,
			    const __u8 *bytes, int len)
{
	int i;

	for (i = 0; i < len; i++)
		async_unwrap_char(stir->netdev, &stir->stats,
				  &stir->rx_buff, bytes[i]);
}

static inline void unwrap_chars(struct stir_cb *stir,
				const __u8 *bytes, int length)
{
	if (isfir(stir->speed))
		stir_fir_chars(stir, bytes, length);
	else
		stir_sir_chars(stir, bytes, length);
}

/* Mode parameters for each speed */
static const struct {
	unsigned speed;
	__u8 pdclk;
} stir_modes[] = {
        { 2400,    PDCLK_2400 },
        { 9600,    PDCLK_9600 },
        { 19200,   PDCLK_19200 },
        { 38400,   PDCLK_38400 },
        { 57600,   PDCLK_57600 },
        { 115200,  PDCLK_115200 },
        { 4000000, PDCLK_4000000 },
};


/*
 * Setup chip for speed.
 *  Called at startup to initialize the chip
 *  and on speed changes.
 *
 * Note: Write multiple registers doesn't appear to work
 */
static int change_speed(struct stir_cb *stir, unsigned speed)
{
	int i, err;
	__u8 mode;

	for (i = 0; i < ARRAY_SIZE(stir_modes); ++i) {
		if (speed == stir_modes[i].speed)
			goto found;
	}

	warn("%s: invalid speed %d", stir->netdev->name, speed);
	return -EINVAL;

 found:
	pr_debug("speed change from %d to %d\n", stir->speed, speed);

	/* Reset modulator */
	err = write_reg(stir, REG_CTRL1, CTRL1_SRESET);
	if (err)
		goto out;

	/* Undocumented magic to tweak the DPLL */
	err = write_reg(stir, REG_DPLL, 0x15);
	if (err)
		goto out;

	/* Set clock */
	err = write_reg(stir, REG_PDCLK, stir_modes[i].pdclk);
	if (err)
		goto out;

	mode = MODE_NRESET | MODE_FASTRX;
	if (isfir(speed))
		mode |= MODE_FIR | MODE_FFRSTEN;
	else
		mode |= MODE_SIR;

	if (speed == 2400)
		mode |= MODE_2400;

	err = write_reg(stir, REG_MODE, mode);
	if (err)
		goto out;

	/* This resets TEMIC style transceiver if any. */
	err = write_reg(stir, REG_CTRL1,
			CTRL1_SDMODE | (tx_power & 3) << 1);
	if (err)
		goto out;

	err = write_reg(stir, REG_CTRL1, (tx_power & 3) << 1);
	if (err)
		goto out;

	/* Reset sensitivity */
	err = write_reg(stir, REG_CTRL2, (rx_sensitivity & 7) << 5);
 out:
	stir->speed = speed;
	return err;
}

/*
 * Called from net/core when new frame is available.
 */
static int stir_hard_xmit(struct sk_buff *skb, struct net_device *netdev)
{
	struct stir_cb *stir = netdev_priv(netdev);

	netif_stop_queue(netdev);

	/* the IRDA wrapping routines don't deal with non linear skb */
	SKB_LINEAR_ASSERT(skb);

	skb = xchg(&stir->tx_pending, skb);
        wake_up_process(stir->thread);
	
	/* this should never happen unless stop/wakeup problem */