i4l.c

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/*
 * Stuff used by all variants of the driver
 *
 * Copyright (c) 2001 by Stefan Eilers,
 *                       Hansjoerg Lipp <[email protected]>,
 *                       Tilman Schmidt <[email protected]>.
 *
 * =====================================================================
 *  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.
 * =====================================================================
 */

#include "gigaset.h"
#include <linux/isdnif.h>
#include <linux/export.h>

#define SBUFSIZE    4096    /* sk_buff payload size */
#define TRANSBUFSIZE    768 /* bytes per skb for transparent receive */
#define HW_HDR_LEN  2   /* Header size used to store ack info */
#define MAX_BUF_SIZE    (SBUFSIZE - HW_HDR_LEN) /* max data packet from LL */

/* == Handling of I4L IO =====================================================*/

/* writebuf_from_LL
 * called by LL to transmit data on an open channel
 * inserts the buffer data into the send queue and starts the transmission
 * Note that this operation must not sleep!
 * When the buffer is processed completely, gigaset_skb_sent() should be called.
 * parameters:
 *  driverID    driver ID as assigned by LL
 *  channel     channel number
 *  ack     if != 0 LL wants to be notified on completion via
 *          statcallb(ISDN_STAT_BSENT)
 *  skb     skb containing data to send
 * return value:
 *  number of accepted bytes
 *  0 if temporarily unable to accept data (out of buffer space)
 *  <0 on error (eg. -EINVAL)
 */
static int writebuf_from_LL(int driverID, int channel, int ack,
                struct sk_buff *skb)
{
    struct cardstate *cs = gigaset_get_cs_by_id(driverID);
    struct bc_state *bcs;
    unsigned char *ack_header;
    unsigned len;

    if (!cs) {
        pr_err("%s: invalid driver ID (%d)\n", __func__, driverID);
        return -ENODEV;
    }
    if (channel < 0 || channel >= cs->channels) {
        dev_err(cs->dev, "%s: invalid channel ID (%d)\n",
            __func__, channel);
        return -ENODEV;
    }
    bcs = &cs->bcs[channel];

    /* can only handle linear sk_buffs */
    if (skb_linearize(skb) < 0) {
        dev_err(cs->dev, "%s: skb_linearize failed\n", __func__);
        return -ENOMEM;
    }
    len = skb->len;

    gig_dbg(DEBUG_LLDATA,
        "Receiving data from LL (id: %d, ch: %d, ack: %d, sz: %d)",
        driverID, channel, ack, len);

    if (!len) {
        if (ack)
            dev_notice(cs->dev, "%s: not ACKing empty packet\n",
                   __func__);
        return 0;
    }
    if (len > MAX_BUF_SIZE) {
        dev_err(cs->dev, "%s: packet too large (%d bytes)\n",
            __func__, len);
        return -EINVAL;
    }

    /* set up acknowledgement header */
    if (skb_headroom(skb) < HW_HDR_LEN) {
        /* should never happen */
        dev_err(cs->dev, "%s: insufficient skb headroom\n", __func__);
        return -ENOMEM;
    }
    skb_set_mac_header(skb, -HW_HDR_LEN);
    skb->mac_len = HW_HDR_LEN;
    ack_header = skb_mac_header(skb);
    if (ack) {
        ack_header[0] = len & 0xff;
        ack_header[1] = len >> 8;
    } else {
        ack_header[0] = ack_header[1] = 0;
    }
    gig_dbg(DEBUG_MCMD, "skb: len=%u, ack=%d: %02x %02x",
        len, ack, ack_header[0], ack_header[1]);

    /* pass to device-specific module */
    return cs->ops->send_skb(bcs, skb);
}

void gigaset_skb_sent(struct bc_state *bcs, struct sk_buff *skb)
{
    isdn_if *iif = bcs->cs->iif;
    unsigned char *ack_header = skb_mac_header(skb);
    unsigned len;
    isdn_ctrl response;

    ++bcs->trans_up;

    if (skb->len)
        dev_warn(bcs->cs->dev, "%s: skb->len==%d\n",
             __func__, skb->len);

    len = ack_header[0] + ((unsigned) ack_header[1] << 8);
    if (len) {
        gig_dbg(DEBUG_MCMD, "ACKing to LL (id: %d, ch: %d, sz: %u)",
            bcs->cs->myid, bcs->channel, len);

        response.driver = bcs->cs->myid;
        response.command = ISDN_STAT_BSENT;
        response.arg = bcs->channel;
        response.parm.length = len;
        iif->statcallb(&response);
    }
}
EXPORT_SYMBOL_GPL(gigaset_skb_sent);

void gigaset_skb_rcvd(struct bc_state *bcs, struct sk_buff *skb)
{
    isdn_if *iif = bcs->cs->iif;

    iif->rcvcallb_skb(bcs->cs->myid, bcs->channel, skb);
    bcs->trans_down++;
}
EXPORT_SYMBOL_GPL(gigaset_skb_rcvd);

void gigaset_isdn_rcv_err(struct bc_state *bcs)
{
    isdn_if *iif = bcs->cs->iif;
    isdn_ctrl response;

    /* if currently ignoring packets, just count down */
    if (bcs->ignore) {
        bcs->ignore--;
        return;
    }

    /* update statistics */
    bcs->corrupted++;

    /* error -> LL */
    gig_dbg(DEBUG_CMD, "sending L1ERR");
    response.driver = bcs->cs->myid;
    response.command = ISDN_STAT_L1ERR;
    response.arg = bcs->channel;
    response.parm.errcode = ISDN_STAT_L1ERR_RECV;
    iif->statcallb(&response);
}
EXPORT_SYMBOL_GPL(gigaset_isdn_rcv_err);

/* This function will be called by LL to send commands
 * NOTE: LL ignores the returned value, for commands other than ISDN_CMD_IOCTL,
 * so don't put too much effort into it.
 */
static int command_from_LL(isdn_ctrl *cntrl)
{
    struct cardstate *cs;
    struct bc_state *bcs;
    int retval = 0;
    char **commands;
    int ch;
    int i;
    size_t l;

    gig_dbg(DEBUG_CMD, "driver: %d, command: %d, arg: 0x%lx",
        cntrl->driver, cntrl->command, cntrl->arg);

    cs = gigaset_get_cs_by_id(cntrl->driver);
    if (cs == NULL) {
        pr_err("%s: invalid driver ID (%d)\n", __func__, cntrl->driver);
        return -ENODEV;
    }
    ch = cntrl->arg & 0xff;

    switch (cntrl->command) {
    case ISDN_CMD_IOCTL:
        dev_warn(cs->dev, "ISDN_CMD_IOCTL not supported\n");
        return -EINVAL;

    case ISDN_CMD_DIAL:
        gig_dbg(DEBUG_CMD,
            "ISDN_CMD_DIAL (phone: %s, msn: %s, si1: %d, si2: %d)",
            cntrl->parm.setup.phone, cntrl->parm.setup.eazmsn,
            cntrl->parm.setup.si1, cntrl->parm.setup.si2);

        if (ch >= cs->channels) {
            dev_err(cs->dev,
                "ISDN_CMD_DIAL: invalid channel (%d)\n", ch);
            return -EINVAL;
        }
        bcs = cs->bcs + ch;
        if (gigaset_get_channel(bcs) < 0) {
            dev_err(cs->dev, "ISDN_CMD_DIAL: channel not free\n");
            return -EBUSY;
        }
        switch (bcs->proto2) {
        case L2_HDLC:
            bcs->rx_bufsize = SBUFSIZE;
            break;
        default:            /* assume transparent */
            bcs->rx_bufsize = TRANSBUFSIZE;
        }
        dev_kfree_skb(bcs->rx_skb);
        gigaset_new_rx_skb(bcs);

        commands = kzalloc(AT_NUM * (sizeof *commands), GFP_ATOMIC);
        if (!commands) {
            gigaset_free_channel(bcs);
            dev_err(cs->dev, "ISDN_CMD_DIAL: out of memory\n");
            return -ENOMEM;
        }

        l = 3 + strlen(cntrl->parm.setup.phone);
        commands[AT_DIAL] = kmalloc(l, GFP_ATOMIC);
        if (!commands[AT_DIAL])
            goto oom;
        if (cntrl->parm.setup.phone[0] == '*' &&
            cntrl->parm.setup.phone[1] == '*') {
            /* internal call: translate ** prefix to CTP value */
            commands[AT_TYPE] = kstrdup("^SCTP=0\r", GFP_ATOMIC);
            if (!commands[AT_TYPE])
                goto oom;
            snprintf(commands[AT_DIAL], l,
                 "D%s\r", cntrl->parm.setup.phone + 2);
        } else {
            commands[AT_TYPE] = kstrdup("^SCTP=1\r", GFP_ATOMIC);
            if (!commands[AT_TYPE])
                goto oom;
            snprintf(commands[AT_DIAL], l,
                 "D%s\r", cntrl->parm.setup.phone);
        }

        l = strlen(cntrl->parm.setup.eazmsn);
        if (l) {
            l += 8;
            commands[AT_MSN] = kmalloc(l, GFP_ATOMIC);
            if (!commands[AT_MSN])
                goto oom;
            snprintf(commands[AT_MSN], l, "^SMSN=%s\r",
                 cntrl->parm.setup.eazmsn);
        }

        switch (cntrl->parm.setup.si1) {
        case 1:     /* audio */
            /* BC = 9090A3: 3.1 kHz audio, A-law */
            commands[AT_BC] = kstrdup("^SBC=9090A3\r", GFP_ATOMIC);
            if (!commands[AT_BC])
                goto oom;
            break;
        case 7:     /* data */
        default:    /* hope the app knows what it is doing */
            /* BC = 8890: unrestricted digital information */
            commands[AT_BC] = kstrdup("^SBC=8890\r", GFP_ATOMIC);
            if (!commands[AT_BC])
                goto oom;
        }
        /* ToDo: other si1 values, inspect si2, set HLC/LLC */

        commands[AT_PROTO] = kmalloc(9, GFP_ATOMIC);
        if (!commands[AT_PROTO])
            goto oom;
        snprintf(commands[AT_PROTO], 9, "^SBPR=%u\r", bcs->proto2);

        commands[AT_ISO] = kmalloc(9, GFP_ATOMIC);
        if (!commands[AT_ISO])
            goto oom;
        snprintf(commands[AT_ISO], 9, "^SISO=%u\r",
             (unsigned) bcs->channel + 1);

        if (!gigaset_add_event(cs, &bcs->at_state, EV_DIAL, commands,
                       bcs->at_state.seq_index, NULL)) {
            for (i = 0; i < AT_NUM; ++i)
                kfree(commands[i]);
            kfree(commands);
            gigaset_free_channel(bcs);
            return -ENOMEM;
        }
        gigaset_schedule_event(cs);
        break;
    case ISDN_CMD_ACCEPTD:
        gig_dbg(DEBUG_CMD, "ISDN_CMD_ACCEPTD");
        if (ch >= cs->channels) {
            dev_err(cs->dev,
                "ISDN_CMD_ACCEPTD: invalid channel (%d)\n", ch);
            return -EINVAL;
        }
        bcs = cs->bcs + ch;
        switch (bcs->proto2) {
        case L2_HDLC:
            bcs->rx_bufsize = SBUFSIZE;
            break;
        default:            /* assume transparent */
            bcs->rx_bufsize = TRANSBUFSIZE;
        }
        dev_kfree_skb(bcs->rx_skb);
        gigaset_new_rx_skb(bcs);
        if (!gigaset_add_event(cs, &bcs->at_state,
                       EV_ACCEPT, NULL, 0, NULL))
            return -ENOMEM;
        gigaset_schedule_event(cs);

        break;
    case ISDN_CMD_HANGUP:
        gig_dbg(DEBUG_CMD, "ISDN_CMD_HANGUP");
        if (ch >= cs->channels) {
            dev_err(cs->dev,
                "ISDN_CMD_HANGUP: invalid channel (%d)\n", ch);
            return -EINVAL;
        }
        bcs = cs->bcs + ch;
        if (!gigaset_add_event(cs, &bcs->at_state,
                       EV_HUP, NULL, 0, NULL))
            return -ENOMEM;
        gigaset_schedule_event(cs);

        break;
    case ISDN_CMD_CLREAZ: /* Do not signal incoming signals */
        dev_info(cs->dev, "ignoring ISDN_CMD_CLREAZ\n");
        break;
    case ISDN_CMD_SETEAZ: /* Signal incoming calls for given MSN */
        dev_info(cs->dev, "ignoring ISDN_CMD_SETEAZ (%s)\n",
             cntrl->parm.num);
        break;
    case ISDN_CMD_SETL2: /* Set L2 to given protocol */
        if (ch >= cs->channels) {
            dev_err(cs->dev,
                "ISDN_CMD_SETL2: invalid channel (%d)\n", ch);
            return -EINVAL;
        }
        bcs = cs->bcs + ch;
        if (bcs->chstate & CHS_D_UP) {
            dev_err(cs->dev,
                "ISDN_CMD_SETL2: channel active (%d)\n", ch);
            return -EINVAL;
        }
        switch (cntrl->arg >> 8) {
        case ISDN_PROTO_L2_HDLC:
            gig_dbg(DEBUG_CMD, "ISDN_CMD_SETL2: setting L2_HDLC");
            bcs->proto2 = L2_HDLC;
            break;
        case ISDN_PROTO_L2_TRANS:
            gig_dbg(DEBUG_CMD, "ISDN_CMD_SETL2: setting L2_VOICE");
            bcs->proto2 = L2_VOICE;
            break;
        default:
            dev_err(cs->dev,
                "ISDN_CMD_SETL2: unsupported protocol (%lu)\n",
                cntrl->arg >> 8);
            return -EINVAL;
        }
        break;
    case ISDN_CMD_SETL3: /* Set L3 to given protocol */
        gig_dbg(DEBUG_CMD, "ISDN_CMD_SETL3");
        if (ch >= cs->channels) {
            dev_err(cs->dev,
                "ISDN_CMD_SETL3: invalid channel (%d)\n", ch);
            return -EINVAL;
        }

        if (cntrl->arg >> 8 != ISDN_PROTO_L3_TRANS) {
            dev_err(cs->dev,
                "ISDN_CMD_SETL3: unsupported protocol (%lu)\n",
                cntrl->arg >> 8);
            return -EINVAL;
        }

        break;

    default:
        gig_dbg(DEBUG_CMD, "unknown command %d from LL",
            cntrl->command);
        return -EINVAL;
    }

    return retval;

oom:
    dev_err(bcs->cs->dev, "out of memory\n");
    for (i = 0; i < AT_NUM; ++i)
        kfree(commands[i]);
    kfree(commands);
    gigaset_free_channel(bcs);
    return -ENOMEM;
}

static void gigaset_i4l_cmd(struct cardstate *cs, int cmd)
{
    isdn_if *iif = cs->iif;
    isdn_ctrl command;

    command.driver = cs->myid;
    command.command = cmd;
    command.arg = 0;
    iif->statcallb(&command);
}

static void gigaset_i4l_channel_cmd(struct bc_state *bcs, int cmd)
{
    isdn_if *iif = bcs->cs->iif;
    isdn_ctrl command;

    command.driver = bcs->cs->myid;
    command.command = cmd;
    command.arg = bcs->channel;
    iif->statcallb(&command);
}

int gigaset_isdn_icall(struct at_state_t *at_state)
{
    struct cardstate *cs = at_state->cs;
    struct bc_state *bcs = at_state->bcs;
    isdn_if *iif = cs->iif;
    isdn_ctrl response;
    int retval;

    /* fill ICALL structure */
    response.parm.setup.si1 = 0;    /* default: unknown */
    response.parm.setup.si2 = 0;
    response.parm.setup.screen = 0;
    response.parm.setup.plan = 0;
    if (!at_state->str_var[STR_ZBC]) {
        /* no BC (internal call): assume speech, A-law */
        response.parm.setup.si1 = 1;
    } else if (!strcmp(at_state->str_var[STR_ZBC], "8890")) {
        /* unrestricted digital information */
        response.parm.setup.si1 = 7;
    } else if (!strcmp(at_state->str_var[STR_ZBC], "8090A3")) {
        /* speech, A-law */
        response.parm.setup.si1 = 1;
    } else if (!strcmp(at_state->str_var[STR_ZBC], "9090A3")) {
        /* 3,1 kHz audio, A-law */
        response.parm.setup.si1 = 1;
        response.parm.setup.si2 = 2;
    } else {
        dev_warn(cs->dev, "RING ignored - unsupported BC %s\n",
             at_state->str_var[STR_ZBC]);
        return ICALL_IGNORE;
    }
    if (at_state->str_var[STR_NMBR]) {
        strlcpy(response.parm.setup.phone, at_state->str_var[STR_NMBR],
            sizeof response.parm.setup.phone);
    } else
        response.parm.setup.phone[0] = 0;
    if (at_state->str_var[STR_ZCPN]) {
        strlcpy(response.parm.setup.eazmsn, at_state->str_var[STR_ZCPN],
            sizeof response.parm.setup.eazmsn);
    } else
        response.parm.setup.eazmsn[0] = 0;

    if (!bcs) {
        dev_notice(cs->dev, "no channel for incoming call\n");
        response.command = ISDN_STAT_ICALLW;
        response.arg = 0;
    } else {
        gig_dbg(DEBUG_CMD, "Sending ICALL");
        response.command = ISDN_STAT_ICALL;
        response.arg = bcs->channel;
    }
    response.driver = cs->myid;
    retval = iif->statcallb(&response);
    gig_dbg(DEBUG_CMD, "Response: %d", retval);
    switch (retval) {
    case 0: /* no takers */
        return ICALL_IGNORE;
    case 1: /* alerting */
        bcs->chstate |= CHS_NOTIFY_LL;
        return ICALL_ACCEPT;
    case 2: /* reject */
        return ICALL_REJECT;
    case 3: /* incomplete */
        dev_warn(cs->dev,
             "LL requested unsupported feature: Incomplete Number\n");
        return ICALL_IGNORE;
    case 4: /* proceeding */
        /* Gigaset will send ALERTING anyway.
         * There doesn't seem to be a way to avoid this.
         */
        return ICALL_ACCEPT;
    case 5: /* deflect */
        dev_warn(cs->dev,
             "LL requested unsupported feature: Call Deflection\n");
        return ICALL_IGNORE;
    default:
        dev_err(cs->dev, "LL error %d on ICALL\n", retval);
        return ICALL_IGNORE;
    }
}

void gigaset_isdn_connD(struct bc_state *bcs)
{
    gig_dbg(DEBUG_CMD, "sending DCONN");
    gigaset_i4l_channel_cmd(bcs, ISDN_STAT_DCONN);
}

void gigaset_isdn_hupD(struct bc_state *bcs)
{
    gig_dbg(DEBUG_CMD, "sending DHUP");
    gigaset_i4l_channel_cmd(bcs, ISDN_STAT_DHUP);
}

void gigaset_isdn_connB(struct bc_state *bcs)
{
    gig_dbg(DEBUG_CMD, "sending BCONN");
    gigaset_i4l_channel_cmd(bcs, ISDN_STAT_BCONN);
}

void gigaset_isdn_hupB(struct bc_state *bcs)
{
    gig_dbg(DEBUG_CMD, "sending BHUP");
    gigaset_i4l_channel_cmd(bcs, ISDN_STAT_BHUP);
}

void gigaset_isdn_start(struct cardstate *cs)
{
    gig_dbg(DEBUG_CMD, "sending RUN");
    gigaset_i4l_cmd(cs, ISDN_STAT_RUN);
}

void gigaset_isdn_stop(struct cardstate *cs)
{
    gig_dbg(DEBUG_CMD, "sending STOP");
    gigaset_i4l_cmd(cs, ISDN_STAT_STOP);
}

int gigaset_isdn_regdev(struct cardstate *cs, const char *isdnid)
{
    isdn_if *iif;

    iif = kmalloc(sizeof *iif, GFP_KERNEL);
    if (!iif) {
        pr_err("out of memory\n");
        return -ENOMEM;
    }

    if (snprintf(iif->id, sizeof iif->id, "%s_%u", isdnid, cs->minor_index)
        >= sizeof iif->id) {
        pr_err("ID too long: %s\n", isdnid);
        kfree(iif);
        return -EINVAL;
    }

    iif->owner = THIS_MODULE;
    iif->channels = cs->channels;
    iif->maxbufsize = MAX_BUF_SIZE;
    iif->features = ISDN_FEATURE_L2_TRANS |
        ISDN_FEATURE_L2_HDLC |
        ISDN_FEATURE_L2_X75I |
        ISDN_FEATURE_L3_TRANS |
        ISDN_FEATURE_P_EURO;
    iif->hl_hdrlen = HW_HDR_LEN;        /* Area for storing ack */
    iif->command = command_from_LL;
    iif->writebuf_skb = writebuf_from_LL;
    iif->writecmd = NULL;           /* Don't support isdnctrl */
    iif->readstat = NULL;           /* Don't support isdnctrl */
    iif->rcvcallb_skb = NULL;       /* Will be set by LL */
    iif->statcallb = NULL;          /* Will be set by LL */

    if (!register_isdn(iif)) {
        pr_err("register_isdn failed\n");
        kfree(iif);
        return -EINVAL;
    }

    cs->iif = iif;
    cs->myid = iif->channels;       /* Set my device id */
    cs->hw_hdr_len = HW_HDR_LEN;
    return 0;
}

void gigaset_isdn_unregdev(struct cardstate *cs)
{
    gig_dbg(DEBUG_CMD, "sending UNLOAD");
    gigaset_i4l_cmd(cs, ISDN_STAT_UNLOAD);
    kfree(cs->iif);
    cs->iif = NULL;
}

void gigaset_isdn_regdrv(void)
{
    pr_info("ISDN4Linux interface\n");
    /* nothing to do */
}

void gigaset_isdn_unregdrv(void)
{
    /* nothing to do */
}