elsa_ser.c

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/* $Id: elsa_ser.c,v 2.14.2.3 2004/02/11 13:21:33 keil Exp $
 *
 * stuff for the serial modem on ELSA cards
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 */

#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <linux/slab.h>

#define MAX_MODEM_BUF   256
#define WAKEUP_CHARS    (MAX_MODEM_BUF / 2)
#define RS_ISR_PASS_LIMIT 256
#define BASE_BAUD (1843200 / 16)

//#define SERIAL_DEBUG_OPEN 1
//#define SERIAL_DEBUG_INTR 1
//#define SERIAL_DEBUG_FLOW 1
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_FLOW
#undef SERIAL_DEBUG_REG
//#define SERIAL_DEBUG_REG 1

#ifdef SERIAL_DEBUG_REG
static u_char deb[32];
const char *ModemIn[] = {"RBR", "IER", "IIR", "LCR", "MCR", "LSR", "MSR", "SCR"};
const char *ModemOut[] = {"THR", "IER", "FCR", "LCR", "MCR", "LSR", "MSR", "SCR"};
#endif

static char *MInit_1 = "AT&F&C1E0&D2\r\0";
static char *MInit_2 = "ATL2M1S64=13\r\0";
static char *MInit_3 = "AT+FCLASS=0\r\0";
static char *MInit_4 = "ATV1S2=128X1\r\0";
static char *MInit_5 = "AT\\V8\\N3\r\0";
static char *MInit_6 = "ATL0M0&G0%E1\r\0";
static char *MInit_7 = "AT%L1%M0%C3\r\0";

static char *MInit_speed28800 = "AT%G0%B28800\r\0";

static char *MInit_dialout = "ATs7=60 x1 d\r\0";
static char *MInit_dialin = "ATs7=60 x1 a\r\0";


static inline unsigned int serial_in(struct IsdnCardState *cs, int offset)
{
#ifdef SERIAL_DEBUG_REG
    u_int val = inb(cs->hw.elsa.base + 8 + offset);
    debugl1(cs, "in   %s %02x", ModemIn[offset], val);
    return (val);
#else
    return inb(cs->hw.elsa.base + 8 + offset);
#endif
}

static inline unsigned int serial_inp(struct IsdnCardState *cs, int offset)
{
#ifdef SERIAL_DEBUG_REG
#ifdef ELSA_SERIAL_NOPAUSE_IO
    u_int val = inb(cs->hw.elsa.base + 8 + offset);
    debugl1(cs, "inp  %s %02x", ModemIn[offset], val);
#else
    u_int val = inb_p(cs->hw.elsa.base + 8 + offset);
    debugl1(cs, "inP  %s %02x", ModemIn[offset], val);
#endif
    return (val);
#else
#ifdef ELSA_SERIAL_NOPAUSE_IO
    return inb(cs->hw.elsa.base + 8 + offset);
#else
    return inb_p(cs->hw.elsa.base + 8 + offset);
#endif
#endif
}

static inline void serial_out(struct IsdnCardState *cs, int offset, int value)
{
#ifdef SERIAL_DEBUG_REG
    debugl1(cs, "out  %s %02x", ModemOut[offset], value);
#endif
    outb(value, cs->hw.elsa.base + 8 + offset);
}

static inline void serial_outp(struct IsdnCardState *cs, int offset,
                   int value)
{
#ifdef SERIAL_DEBUG_REG
#ifdef ELSA_SERIAL_NOPAUSE_IO
    debugl1(cs, "outp %s %02x", ModemOut[offset], value);
#else
    debugl1(cs, "outP %s %02x", ModemOut[offset], value);
#endif
#endif
#ifdef ELSA_SERIAL_NOPAUSE_IO
    outb(value, cs->hw.elsa.base + 8 + offset);
#else
    outb_p(value, cs->hw.elsa.base + 8 + offset);
#endif
}

/*
 * This routine is called to set the UART divisor registers to match
 * the specified baud rate for a serial port.
 */
static void change_speed(struct IsdnCardState *cs, int baud)
{
    int quot = 0, baud_base;
    unsigned cval, fcr = 0;


    /* byte size and parity */
    cval = 0x03;
    /* Determine divisor based on baud rate */
    baud_base = BASE_BAUD;
    quot = baud_base / baud;
    /* If the quotient is ever zero, default to 9600 bps */
    if (!quot)
        quot = baud_base / 9600;

    /* Set up FIFO's */
    if ((baud_base / quot) < 2400)
        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
    else
        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_8;
    serial_outp(cs, UART_FCR, fcr);
    /* CTS flow control flag and modem status interrupts */
    cs->hw.elsa.IER &= ~UART_IER_MSI;
    cs->hw.elsa.IER |= UART_IER_MSI;
    serial_outp(cs, UART_IER, cs->hw.elsa.IER);

    debugl1(cs, "modem quot=0x%x", quot);
    serial_outp(cs, UART_LCR, cval | UART_LCR_DLAB);/* set DLAB */
    serial_outp(cs, UART_DLL, quot & 0xff);     /* LS of divisor */
    serial_outp(cs, UART_DLM, quot >> 8);       /* MS of divisor */
    serial_outp(cs, UART_LCR, cval);        /* reset DLAB */
    serial_inp(cs, UART_RX);
}

static int mstartup(struct IsdnCardState *cs)
{
    int retval = 0;

    /*
     * Clear the FIFO buffers and disable them
     * (they will be reenabled in change_speed())
     */
    serial_outp(cs, UART_FCR, (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT));

    /*
     * At this point there's no way the LSR could still be 0xFF;
     * if it is, then bail out, because there's likely no UART
     * here.
     */
    if (serial_inp(cs, UART_LSR) == 0xff) {
        retval = -ENODEV;
        goto errout;
    }

    /*
     * Clear the interrupt registers.
     */
    (void) serial_inp(cs, UART_RX);
    (void) serial_inp(cs, UART_IIR);
    (void) serial_inp(cs, UART_MSR);

    /*
     * Now, initialize the UART
     */
    serial_outp(cs, UART_LCR, UART_LCR_WLEN8);  /* reset DLAB */

    cs->hw.elsa.MCR = 0;
    cs->hw.elsa.MCR = UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2;
    serial_outp(cs, UART_MCR, cs->hw.elsa.MCR);

    /*
     * Finally, enable interrupts
     */
    cs->hw.elsa.IER = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI;
    serial_outp(cs, UART_IER, cs->hw.elsa.IER); /* enable interrupts */

    /*
     * And clear the interrupt registers again for luck.
     */
    (void)serial_inp(cs, UART_LSR);
    (void)serial_inp(cs, UART_RX);
    (void)serial_inp(cs, UART_IIR);
    (void)serial_inp(cs, UART_MSR);

    cs->hw.elsa.transcnt = cs->hw.elsa.transp = 0;
    cs->hw.elsa.rcvcnt = cs->hw.elsa.rcvp = 0;

    /*
     * and set the speed of the serial port
     */
    change_speed(cs, BASE_BAUD);
    cs->hw.elsa.MFlag = 1;
errout:
    return retval;
}

/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void mshutdown(struct IsdnCardState *cs)
{

#ifdef SERIAL_DEBUG_OPEN
    printk(KERN_DEBUG"Shutting down serial ....");
#endif

    /*
     * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
     * here so the queue might never be waken up
     */

    cs->hw.elsa.IER = 0;
    serial_outp(cs, UART_IER, 0x00);    /* disable all intrs */
    cs->hw.elsa.MCR &= ~UART_MCR_OUT2;

    /* disable break condition */
    serial_outp(cs, UART_LCR, serial_inp(cs, UART_LCR) & ~UART_LCR_SBC);

    cs->hw.elsa.MCR &= ~(UART_MCR_DTR | UART_MCR_RTS);
    serial_outp(cs, UART_MCR, cs->hw.elsa.MCR);

    /* disable FIFO's */
    serial_outp(cs, UART_FCR, (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT));
    serial_inp(cs, UART_RX);    /* read data port to reset things */

#ifdef SERIAL_DEBUG_OPEN
    printk(" done\n");
#endif
}

static inline int
write_modem(struct BCState *bcs) {
    int ret = 0;
    struct IsdnCardState *cs = bcs->cs;
    int count, len, fp;

    if (!bcs->tx_skb)
        return 0;
    if (bcs->tx_skb->len <= 0)
        return 0;
    len = bcs->tx_skb->len;
    if (len > MAX_MODEM_BUF - cs->hw.elsa.transcnt)
        len = MAX_MODEM_BUF - cs->hw.elsa.transcnt;
    fp = cs->hw.elsa.transcnt + cs->hw.elsa.transp;
    fp &= (MAX_MODEM_BUF - 1);
    count = len;
    if (count > MAX_MODEM_BUF - fp) {
        count = MAX_MODEM_BUF - fp;
        skb_copy_from_linear_data(bcs->tx_skb,
                      cs->hw.elsa.transbuf + fp, count);
        skb_pull(bcs->tx_skb, count);
        cs->hw.elsa.transcnt += count;
        ret = count;
        count = len - count;
        fp = 0;
    }
    skb_copy_from_linear_data(bcs->tx_skb,
                  cs->hw.elsa.transbuf + fp, count);
    skb_pull(bcs->tx_skb, count);
    cs->hw.elsa.transcnt += count;
    ret += count;

    if (cs->hw.elsa.transcnt &&
        !(cs->hw.elsa.IER & UART_IER_THRI)) {
        cs->hw.elsa.IER |= UART_IER_THRI;
        serial_outp(cs, UART_IER, cs->hw.elsa.IER);
    }
    return (ret);
}

static inline void
modem_fill(struct BCState *bcs) {

    if (bcs->tx_skb) {
        if (bcs->tx_skb->len) {
            write_modem(bcs);
            return;
        } else {
            if (test_bit(FLG_LLI_L1WAKEUP, &bcs->st->lli.flag) &&
                (PACKET_NOACK != bcs->tx_skb->pkt_type)) {
                u_long  flags;
                spin_lock_irqsave(&bcs->aclock, flags);
                bcs->ackcnt += bcs->hw.hscx.count;
                spin_unlock_irqrestore(&bcs->aclock, flags);
                schedule_event(bcs, B_ACKPENDING);
            }
            dev_kfree_skb_any(bcs->tx_skb);
            bcs->tx_skb = NULL;
        }
    }
    if ((bcs->tx_skb = skb_dequeue(&bcs->squeue))) {
        bcs->hw.hscx.count = 0;
        test_and_set_bit(BC_FLG_BUSY, &bcs->Flag);
        write_modem(bcs);
    } else {
        test_and_clear_bit(BC_FLG_BUSY, &bcs->Flag);
        schedule_event(bcs, B_XMTBUFREADY);
    }
}

static inline void receive_chars(struct IsdnCardState *cs,
                 int *status)
{
    unsigned char ch;
    struct sk_buff *skb;

    do {
        ch = serial_in(cs, UART_RX);
        if (cs->hw.elsa.rcvcnt >= MAX_MODEM_BUF)
            break;
        cs->hw.elsa.rcvbuf[cs->hw.elsa.rcvcnt++] = ch;
#ifdef SERIAL_DEBUG_INTR
        printk("DR%02x:%02x...", ch, *status);
#endif
        if (*status & (UART_LSR_BI | UART_LSR_PE |
                   UART_LSR_FE | UART_LSR_OE)) {

#ifdef SERIAL_DEBUG_INTR
            printk("handling exept....");
#endif
        }
        *status = serial_inp(cs, UART_LSR);
    } while (*status & UART_LSR_DR);
    if (cs->hw.elsa.MFlag == 2) {
        if (!(skb = dev_alloc_skb(cs->hw.elsa.rcvcnt)))
            printk(KERN_WARNING "ElsaSER: receive out of memory\n");
        else {
            memcpy(skb_put(skb, cs->hw.elsa.rcvcnt), cs->hw.elsa.rcvbuf,
                   cs->hw.elsa.rcvcnt);
            skb_queue_tail(&cs->hw.elsa.bcs->rqueue, skb);
        }
        schedule_event(cs->hw.elsa.bcs, B_RCVBUFREADY);
    } else {
        char tmp[128];
        char *t = tmp;

        t += sprintf(t, "modem read cnt %d", cs->hw.elsa.rcvcnt);
        QuickHex(t, cs->hw.elsa.rcvbuf, cs->hw.elsa.rcvcnt);
        debugl1(cs, tmp);
    }
    cs->hw.elsa.rcvcnt = 0;
}

static inline void transmit_chars(struct IsdnCardState *cs, int *intr_done)
{
    int count;

    debugl1(cs, "transmit_chars: p(%x) cnt(%x)", cs->hw.elsa.transp,
        cs->hw.elsa.transcnt);

    if (cs->hw.elsa.transcnt <= 0) {
        cs->hw.elsa.IER &= ~UART_IER_THRI;
        serial_out(cs, UART_IER, cs->hw.elsa.IER);
        return;
    }
    count = 16;
    do {
        serial_outp(cs, UART_TX, cs->hw.elsa.transbuf[cs->hw.elsa.transp++]);
        if (cs->hw.elsa.transp >= MAX_MODEM_BUF)
            cs->hw.elsa.transp = 0;
        if (--cs->hw.elsa.transcnt <= 0)
            break;
    } while (--count > 0);
    if ((cs->hw.elsa.transcnt < WAKEUP_CHARS) && (cs->hw.elsa.MFlag == 2))
        modem_fill(cs->hw.elsa.bcs);

#ifdef SERIAL_DEBUG_INTR
    printk("THRE...");
#endif
    if (intr_done)
        *intr_done = 0;
    if (cs->hw.elsa.transcnt <= 0) {
        cs->hw.elsa.IER &= ~UART_IER_THRI;
        serial_outp(cs, UART_IER, cs->hw.elsa.IER);
    }
}


static void rs_interrupt_elsa(struct IsdnCardState *cs)
{
    int status, iir, msr;
    int pass_counter = 0;

#ifdef SERIAL_DEBUG_INTR
    printk(KERN_DEBUG "rs_interrupt_single(%d)...", cs->irq);
#endif

    do {
        status = serial_inp(cs, UART_LSR);
        debugl1(cs, "rs LSR %02x", status);
#ifdef SERIAL_DEBUG_INTR
        printk("status = %x...", status);
#endif
        if (status & UART_LSR_DR)
            receive_chars(cs, &status);
        if (status & UART_LSR_THRE)
            transmit_chars(cs, NULL);
        if (pass_counter++ > RS_ISR_PASS_LIMIT) {
            printk("rs_single loop break.\n");
            break;
        }
        iir = serial_inp(cs, UART_IIR);
        debugl1(cs, "rs IIR %02x", iir);
        if ((iir & 0xf) == 0) {
            msr = serial_inp(cs, UART_MSR);
            debugl1(cs, "rs MSR %02x", msr);
        }
    } while (!(iir & UART_IIR_NO_INT));
#ifdef SERIAL_DEBUG_INTR
    printk("end.\n");
#endif
}

extern int open_hscxstate(struct IsdnCardState *cs, struct BCState *bcs);
extern void modehscx(struct BCState *bcs, int mode, int bc);
extern void hscx_l2l1(struct PStack *st, int pr, void *arg);

static void
close_elsastate(struct BCState *bcs)
{
    modehscx(bcs, 0, bcs->channel);
    if (test_and_clear_bit(BC_FLG_INIT, &bcs->Flag)) {
        if (bcs->hw.hscx.rcvbuf) {
            if (bcs->mode != L1_MODE_MODEM)
                kfree(bcs->hw.hscx.rcvbuf);
            bcs->hw.hscx.rcvbuf = NULL;
        }
        skb_queue_purge(&bcs->rqueue);
        skb_queue_purge(&bcs->squeue);
        if (bcs->tx_skb) {
            dev_kfree_skb_any(bcs->tx_skb);
            bcs->tx_skb = NULL;
            test_and_clear_bit(BC_FLG_BUSY, &bcs->Flag);
        }
    }
}

static void
modem_write_cmd(struct IsdnCardState *cs, u_char *buf, int len) {
    int count, fp;
    u_char *msg = buf;

    if (!len)
        return;
    if (len > (MAX_MODEM_BUF - cs->hw.elsa.transcnt)) {
        return;
    }
    fp = cs->hw.elsa.transcnt + cs->hw.elsa.transp;
    fp &= (MAX_MODEM_BUF - 1);
    count = len;
    if (count > MAX_MODEM_BUF - fp) {
        count = MAX_MODEM_BUF - fp;
        memcpy(cs->hw.elsa.transbuf + fp, msg, count);
        cs->hw.elsa.transcnt += count;
        msg += count;
        count = len - count;
        fp = 0;
    }
    memcpy(cs->hw.elsa.transbuf + fp, msg, count);
    cs->hw.elsa.transcnt += count;
    if (cs->hw.elsa.transcnt &&
        !(cs->hw.elsa.IER & UART_IER_THRI)) {
        cs->hw.elsa.IER |= UART_IER_THRI;
        serial_outp(cs, UART_IER, cs->hw.elsa.IER);
    }
}

static void
modem_set_init(struct IsdnCardState *cs) {
    int timeout;

#define RCV_DELAY 20
    modem_write_cmd(cs, MInit_1, strlen(MInit_1));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
    modem_write_cmd(cs, MInit_2, strlen(MInit_2));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
    modem_write_cmd(cs, MInit_3, strlen(MInit_3));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
    modem_write_cmd(cs, MInit_4, strlen(MInit_4));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
    modem_write_cmd(cs, MInit_5, strlen(MInit_5));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
    modem_write_cmd(cs, MInit_6, strlen(MInit_6));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
    modem_write_cmd(cs, MInit_7, strlen(MInit_7));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
}

static void
modem_set_dial(struct IsdnCardState *cs, int outgoing) {
    int timeout;
#define RCV_DELAY 20

    modem_write_cmd(cs, MInit_speed28800, strlen(MInit_speed28800));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
    if (outgoing)
        modem_write_cmd(cs, MInit_dialout, strlen(MInit_dialout));
    else
        modem_write_cmd(cs, MInit_dialin, strlen(MInit_dialin));
    timeout = 1000;
    while (timeout-- && cs->hw.elsa.transcnt)
        udelay(1000);
    debugl1(cs, "msi tout=%d", timeout);
    mdelay(RCV_DELAY);
}

static void
modem_l2l1(struct PStack *st, int pr, void *arg)
{
    struct BCState *bcs = st->l1.bcs;
    struct sk_buff *skb = arg;
    u_long flags;

    if (pr == (PH_DATA | REQUEST)) {
        spin_lock_irqsave(&bcs->cs->lock, flags);
        if (bcs->tx_skb) {
            skb_queue_tail(&bcs->squeue, skb);
        } else {
            bcs->tx_skb = skb;
            test_and_set_bit(BC_FLG_BUSY, &bcs->Flag);
            bcs->hw.hscx.count = 0;
            write_modem(bcs);
        }
        spin_unlock_irqrestore(&bcs->cs->lock, flags);
    } else if (pr == (PH_ACTIVATE | REQUEST)) {
        test_and_set_bit(BC_FLG_ACTIV, &bcs->Flag);
        st->l1.l1l2(st, PH_ACTIVATE | CONFIRM, NULL);
        set_arcofi(bcs->cs, st->l1.bc);
        mstartup(bcs->cs);
        modem_set_dial(bcs->cs, test_bit(FLG_ORIG, &st->l2.flag));
        bcs->cs->hw.elsa.MFlag = 2;
    } else if (pr == (PH_DEACTIVATE | REQUEST)) {
        test_and_clear_bit(BC_FLG_ACTIV, &bcs->Flag);
        bcs->cs->dc.isac.arcofi_bc = st->l1.bc;
        arcofi_fsm(bcs->cs, ARCOFI_START, &ARCOFI_XOP_0);
        interruptible_sleep_on(&bcs->cs->dc.isac.arcofi_wait);
        bcs->cs->hw.elsa.MFlag = 1;
    } else {
        printk(KERN_WARNING "ElsaSer: unknown pr %x\n", pr);
    }
}

static int
setstack_elsa(struct PStack *st, struct BCState *bcs)
{

    bcs->channel = st->l1.bc;
    switch (st->l1.mode) {
    case L1_MODE_HDLC:
    case L1_MODE_TRANS:
        if (open_hscxstate(st->l1.hardware, bcs))
            return (-1);
        st->l2.l2l1 = hscx_l2l1;
        break;
    case L1_MODE_MODEM:
        bcs->mode = L1_MODE_MODEM;
        if (!test_and_set_bit(BC_FLG_INIT, &bcs->Flag)) {
            bcs->hw.hscx.rcvbuf = bcs->cs->hw.elsa.rcvbuf;
            skb_queue_head_init(&bcs->rqueue);
            skb_queue_head_init(&bcs->squeue);
        }
        bcs->tx_skb = NULL;
        test_and_clear_bit(BC_FLG_BUSY, &bcs->Flag);
        bcs->event = 0;
        bcs->hw.hscx.rcvidx = 0;
        bcs->tx_cnt = 0;
        bcs->cs->hw.elsa.bcs = bcs;
        st->l2.l2l1 = modem_l2l1;
        break;
    }
    st->l1.bcs = bcs;
    setstack_manager(st);
    bcs->st = st;
    setstack_l1_B(st);
    return (0);
}

static void
init_modem(struct IsdnCardState *cs) {

    cs->bcs[0].BC_SetStack = setstack_elsa;
    cs->bcs[1].BC_SetStack = setstack_elsa;
    cs->bcs[0].BC_Close = close_elsastate;
    cs->bcs[1].BC_Close = close_elsastate;
    if (!(cs->hw.elsa.rcvbuf = kmalloc(MAX_MODEM_BUF,
                       GFP_ATOMIC))) {
        printk(KERN_WARNING
               "Elsa: No modem mem hw.elsa.rcvbuf\n");
        return;
    }
    if (!(cs->hw.elsa.transbuf = kmalloc(MAX_MODEM_BUF,
                         GFP_ATOMIC))) {
        printk(KERN_WARNING
               "Elsa: No modem mem hw.elsa.transbuf\n");
        kfree(cs->hw.elsa.rcvbuf);
        cs->hw.elsa.rcvbuf = NULL;
        return;
    }
    if (mstartup(cs)) {
        printk(KERN_WARNING "Elsa: problem startup modem\n");
    }
    modem_set_init(cs);
}

static void
release_modem(struct IsdnCardState *cs) {

    cs->hw.elsa.MFlag = 0;
    if (cs->hw.elsa.transbuf) {
        if (cs->hw.elsa.rcvbuf) {
            mshutdown(cs);
            kfree(cs->hw.elsa.rcvbuf);
            cs->hw.elsa.rcvbuf = NULL;
        }
        kfree(cs->hw.elsa.transbuf);
        cs->hw.elsa.transbuf = NULL;
    }
}