viohs.c

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/* viohs.c: LDOM Virtual I/O handshake helper layer.
 *
 * Copyright (C) 2007 David S. Miller <[email protected]>
 */

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/slab.h>

#include <asm/ldc.h>
#include <asm/vio.h>

int vio_ldc_send(struct vio_driver_state *vio, void *data, int len)
{
    int err, limit = 1000;

    err = -EINVAL;
    while (limit-- > 0) {
        err = ldc_write(vio->lp, data, len);
        if (!err || (err != -EAGAIN))
            break;
        udelay(1);
    }

    return err;
}
EXPORT_SYMBOL(vio_ldc_send);

static int send_ctrl(struct vio_driver_state *vio,
             struct vio_msg_tag *tag, int len)
{
    tag->sid = vio_send_sid(vio);
    return vio_ldc_send(vio, tag, len);
}

static void init_tag(struct vio_msg_tag *tag, u8 type, u8 stype, u16 stype_env)
{
    tag->type = type;
    tag->stype = stype;
    tag->stype_env = stype_env;
}

static int send_version(struct vio_driver_state *vio, u16 major, u16 minor)
{
    struct vio_ver_info pkt;

    vio->_local_sid = (u32) sched_clock();

    memset(&pkt, 0, sizeof(pkt));
    init_tag(&pkt.tag, VIO_TYPE_CTRL, VIO_SUBTYPE_INFO, VIO_VER_INFO);
    pkt.major = major;
    pkt.minor = minor;
    pkt.dev_class = vio->dev_class;

    viodbg(HS, "SEND VERSION INFO maj[%u] min[%u] devclass[%u]\n",
           major, minor, vio->dev_class);

    return send_ctrl(vio, &pkt.tag, sizeof(pkt));
}

static int start_handshake(struct vio_driver_state *vio)
{
    int err;

    viodbg(HS, "START HANDSHAKE\n");

    vio->hs_state = VIO_HS_INVALID;

    err = send_version(vio,
               vio->ver_table[0].major,
               vio->ver_table[0].minor);
    if (err < 0)
        return err;

    return 0;
}

static void flush_rx_dring(struct vio_driver_state *vio)
{
    struct vio_dring_state *dr;
    u64 ident;

    BUG_ON(!(vio->dr_state & VIO_DR_STATE_RXREG));

    dr = &vio->drings[VIO_DRIVER_RX_RING];
    ident = dr->ident;

    BUG_ON(!vio->desc_buf);
    kfree(vio->desc_buf);
    vio->desc_buf = NULL;

    memset(dr, 0, sizeof(*dr));
    dr->ident = ident;
}

void vio_link_state_change(struct vio_driver_state *vio, int event)
{
    if (event == LDC_EVENT_UP) {
        vio->hs_state = VIO_HS_INVALID;

        switch (vio->dev_class) {
        case VDEV_NETWORK:
        case VDEV_NETWORK_SWITCH:
            vio->dr_state = (VIO_DR_STATE_TXREQ |
                     VIO_DR_STATE_RXREQ);
            break;

        case VDEV_DISK:
            vio->dr_state = VIO_DR_STATE_TXREQ;
            break;
        case VDEV_DISK_SERVER:
            vio->dr_state = VIO_DR_STATE_RXREQ;
            break;
        }
        start_handshake(vio);
    } else if (event == LDC_EVENT_RESET) {
        vio->hs_state = VIO_HS_INVALID;

        if (vio->dr_state & VIO_DR_STATE_RXREG)
            flush_rx_dring(vio);

        vio->dr_state = 0x00;
        memset(&vio->ver, 0, sizeof(vio->ver));

        ldc_disconnect(vio->lp);
    }
}
EXPORT_SYMBOL(vio_link_state_change);

static int handshake_failure(struct vio_driver_state *vio)
{
    struct vio_dring_state *dr;

    /* XXX Put policy here...  Perhaps start a timer to fire
     * XXX in 100 ms, which will bring the link up and retry
     * XXX the handshake.
     */

    viodbg(HS, "HANDSHAKE FAILURE\n");

    vio->dr_state &= ~(VIO_DR_STATE_TXREG |
               VIO_DR_STATE_RXREG);

    dr = &vio->drings[VIO_DRIVER_RX_RING];
    memset(dr, 0, sizeof(*dr));

    kfree(vio->desc_buf);
    vio->desc_buf = NULL;
    vio->desc_buf_len = 0;

    vio->hs_state = VIO_HS_INVALID;

    return -ECONNRESET;
}

static int process_unknown(struct vio_driver_state *vio, void *arg)
{
    struct vio_msg_tag *pkt = arg;

    viodbg(HS, "UNKNOWN CONTROL [%02x:%02x:%04x:%08x]\n",
           pkt->type, pkt->stype, pkt->stype_env, pkt->sid);

    printk(KERN_ERR "vio: ID[%lu] Resetting connection.\n",
           vio->vdev->channel_id);

    ldc_disconnect(vio->lp);

    return -ECONNRESET;
}

static int send_dreg(struct vio_driver_state *vio)
{
    struct vio_dring_state *dr = &vio->drings[VIO_DRIVER_TX_RING];
    union {
        struct vio_dring_register pkt;
        char all[sizeof(struct vio_dring_register) +
             (sizeof(struct ldc_trans_cookie) *
              dr->ncookies)];
    } u;
    int i;

    memset(&u, 0, sizeof(u));
    init_tag(&u.pkt.tag, VIO_TYPE_CTRL, VIO_SUBTYPE_INFO, VIO_DRING_REG);
    u.pkt.dring_ident = 0;
    u.pkt.num_descr = dr->num_entries;
    u.pkt.descr_size = dr->entry_size;
    u.pkt.options = VIO_TX_DRING;
    u.pkt.num_cookies = dr->ncookies;

    viodbg(HS, "SEND DRING_REG INFO ndesc[%u] dsz[%u] opt[0x%x] "
           "ncookies[%u]\n",
           u.pkt.num_descr, u.pkt.descr_size, u.pkt.options,
           u.pkt.num_cookies);

    for (i = 0; i < dr->ncookies; i++) {
        u.pkt.cookies[i] = dr->cookies[i];

        viodbg(HS, "DRING COOKIE(%d) [%016llx:%016llx]\n",
               i,
               (unsigned long long) u.pkt.cookies[i].cookie_addr,
               (unsigned long long) u.pkt.cookies[i].cookie_size);
    }

    return send_ctrl(vio, &u.pkt.tag, sizeof(u));
}

static int send_rdx(struct vio_driver_state *vio)
{
    struct vio_rdx pkt;

    memset(&pkt, 0, sizeof(pkt));

    init_tag(&pkt.tag, VIO_TYPE_CTRL, VIO_SUBTYPE_INFO, VIO_RDX);

    viodbg(HS, "SEND RDX INFO\n");

    return send_ctrl(vio, &pkt.tag, sizeof(pkt));
}

static int send_attr(struct vio_driver_state *vio)
{
    return vio->ops->send_attr(vio);
}

static struct vio_version *find_by_major(struct vio_driver_state *vio,
                     u16 major)
{
    struct vio_version *ret = NULL;
    int i;

    for (i = 0; i < vio->ver_table_entries; i++) {
        struct vio_version *v = &vio->ver_table[i];
        if (v->major <= major) {
            ret = v;
            break;
        }
    }
    return ret;
}

static int process_ver_info(struct vio_driver_state *vio,
                struct vio_ver_info *pkt)
{
    struct vio_version *vap;
    int err;

    viodbg(HS, "GOT VERSION INFO maj[%u] min[%u] devclass[%u]\n",
           pkt->major, pkt->minor, pkt->dev_class);

    if (vio->hs_state != VIO_HS_INVALID) {
        /* XXX Perhaps invoke start_handshake? XXX */
        memset(&vio->ver, 0, sizeof(vio->ver));
        vio->hs_state = VIO_HS_INVALID;
    }

    vap = find_by_major(vio, pkt->major);

    vio->_peer_sid = pkt->tag.sid;

    if (!vap) {
        pkt->tag.stype = VIO_SUBTYPE_NACK;
        pkt->major = 0;
        pkt->minor = 0;
        viodbg(HS, "SEND VERSION NACK maj[0] min[0]\n");
        err = send_ctrl(vio, &pkt->tag, sizeof(*pkt));
    } else if (vap->major != pkt->major) {
        pkt->tag.stype = VIO_SUBTYPE_NACK;
        pkt->major = vap->major;
        pkt->minor = vap->minor;
        viodbg(HS, "SEND VERSION NACK maj[%u] min[%u]\n",
               pkt->major, pkt->minor);
        err = send_ctrl(vio, &pkt->tag, sizeof(*pkt));
    } else {
        struct vio_version ver = {
            .major = pkt->major,
            .minor = pkt->minor,
        };
        if (ver.minor > vap->minor)
            ver.minor = vap->minor;
        pkt->minor = ver.minor;
        pkt->tag.stype = VIO_SUBTYPE_ACK;
        viodbg(HS, "SEND VERSION ACK maj[%u] min[%u]\n",
               pkt->major, pkt->minor);
        err = send_ctrl(vio, &pkt->tag, sizeof(*pkt));
        if (err > 0) {
            vio->ver = ver;
            vio->hs_state = VIO_HS_GOTVERS;
        }
    }
    if (err < 0)
        return handshake_failure(vio);

    return 0;
}

static int process_ver_ack(struct vio_driver_state *vio,
               struct vio_ver_info *pkt)
{
    viodbg(HS, "GOT VERSION ACK maj[%u] min[%u] devclass[%u]\n",
           pkt->major, pkt->minor, pkt->dev_class);

    if (vio->hs_state & VIO_HS_GOTVERS) {
        if (vio->ver.major != pkt->major ||
            vio->ver.minor != pkt->minor) {
            pkt->tag.stype = VIO_SUBTYPE_NACK;
            (void) send_ctrl(vio, &pkt->tag, sizeof(*pkt));
            return handshake_failure(vio);
        }
    } else {
        vio->ver.major = pkt->major;
        vio->ver.minor = pkt->minor;
        vio->hs_state = VIO_HS_GOTVERS;
    }

    switch (vio->dev_class) {
    case VDEV_NETWORK:
    case VDEV_DISK:
        if (send_attr(vio) < 0)
            return handshake_failure(vio);
        break;

    default:
        break;
    }

    return 0;
}

static int process_ver_nack(struct vio_driver_state *vio,
                struct vio_ver_info *pkt)
{
    struct vio_version *nver;

    viodbg(HS, "GOT VERSION NACK maj[%u] min[%u] devclass[%u]\n",
           pkt->major, pkt->minor, pkt->dev_class);

    if (pkt->major == 0 && pkt->minor == 0)
        return handshake_failure(vio);
    nver = find_by_major(vio, pkt->major);
    if (!nver)
        return handshake_failure(vio);

    if (send_version(vio, nver->major, nver->minor) < 0)
        return handshake_failure(vio);

    return 0;
}

static int process_ver(struct vio_driver_state *vio, struct vio_ver_info *pkt)
{
    switch (pkt->tag.stype) {
    case VIO_SUBTYPE_INFO:
        return process_ver_info(vio, pkt);

    case VIO_SUBTYPE_ACK:
        return process_ver_ack(vio, pkt);

    case VIO_SUBTYPE_NACK:
        return process_ver_nack(vio, pkt);

    default:
        return handshake_failure(vio);
    }
}

static int process_attr(struct vio_driver_state *vio, void *pkt)
{
    int err;

    if (!(vio->hs_state & VIO_HS_GOTVERS))
        return handshake_failure(vio);

    err = vio->ops->handle_attr(vio, pkt);
    if (err < 0) {
        return handshake_failure(vio);
    } else {
        vio->hs_state |= VIO_HS_GOT_ATTR;

        if ((vio->dr_state & VIO_DR_STATE_TXREQ) &&
            !(vio->hs_state & VIO_HS_SENT_DREG)) {
            if (send_dreg(vio) < 0)
                return handshake_failure(vio);

            vio->hs_state |= VIO_HS_SENT_DREG;
        }
    }
    return 0;
}

static int all_drings_registered(struct vio_driver_state *vio)
{
    int need_rx, need_tx;

    need_rx = (vio->dr_state & VIO_DR_STATE_RXREQ);
    need_tx = (vio->dr_state & VIO_DR_STATE_TXREQ);

    if (need_rx &&
        !(vio->dr_state & VIO_DR_STATE_RXREG))
        return 0;

    if (need_tx &&
        !(vio->dr_state & VIO_DR_STATE_TXREG))
        return 0;

    return 1;
}

static int process_dreg_info(struct vio_driver_state *vio,
                 struct vio_dring_register *pkt)
{
    struct vio_dring_state *dr;
    int i, len;

    viodbg(HS, "GOT DRING_REG INFO ident[%llx] "
           "ndesc[%u] dsz[%u] opt[0x%x] ncookies[%u]\n",
           (unsigned long long) pkt->dring_ident,
           pkt->num_descr, pkt->descr_size, pkt->options,
           pkt->num_cookies);

    if (!(vio->dr_state & VIO_DR_STATE_RXREQ))
        goto send_nack;

    if (vio->dr_state & VIO_DR_STATE_RXREG)
        goto send_nack;

    BUG_ON(vio->desc_buf);

    vio->desc_buf = kzalloc(pkt->descr_size, GFP_ATOMIC);
    if (!vio->desc_buf)
        goto send_nack;

    vio->desc_buf_len = pkt->descr_size;

    dr = &vio->drings[VIO_DRIVER_RX_RING];

    dr->num_entries = pkt->num_descr;
    dr->entry_size = pkt->descr_size;
    dr->ncookies = pkt->num_cookies;
    for (i = 0; i < dr->ncookies; i++) {
        dr->cookies[i] = pkt->cookies[i];

        viodbg(HS, "DRING COOKIE(%d) [%016llx:%016llx]\n",
               i,
               (unsigned long long)
               pkt->cookies[i].cookie_addr,
               (unsigned long long)
               pkt->cookies[i].cookie_size);
    }

    pkt->tag.stype = VIO_SUBTYPE_ACK;
    pkt->dring_ident = ++dr->ident;

    viodbg(HS, "SEND DRING_REG ACK ident[%llx]\n",
           (unsigned long long) pkt->dring_ident);

    len = (sizeof(*pkt) +
           (dr->ncookies * sizeof(struct ldc_trans_cookie)));
    if (send_ctrl(vio, &pkt->tag, len) < 0)
        goto send_nack;

    vio->dr_state |= VIO_DR_STATE_RXREG;

    return 0;

send_nack:
    pkt->tag.stype = VIO_SUBTYPE_NACK;
    viodbg(HS, "SEND DRING_REG NACK\n");
    (void) send_ctrl(vio, &pkt->tag, sizeof(*pkt));

    return handshake_failure(vio);
}

static int process_dreg_ack(struct vio_driver_state *vio,
                struct vio_dring_register *pkt)
{
    struct vio_dring_state *dr;

    viodbg(HS, "GOT DRING_REG ACK ident[%llx] "
           "ndesc[%u] dsz[%u] opt[0x%x] ncookies[%u]\n",
           (unsigned long long) pkt->dring_ident,
           pkt->num_descr, pkt->descr_size, pkt->options,
           pkt->num_cookies);

    dr = &vio->drings[VIO_DRIVER_TX_RING];

    if (!(vio->dr_state & VIO_DR_STATE_TXREQ))
        return handshake_failure(vio);

    dr->ident = pkt->dring_ident;
    vio->dr_state |= VIO_DR_STATE_TXREG;

    if (all_drings_registered(vio)) {
        if (send_rdx(vio) < 0)
            return handshake_failure(vio);
        vio->hs_state = VIO_HS_SENT_RDX;
    }
    return 0;
}

static int process_dreg_nack(struct vio_driver_state *vio,
                 struct vio_dring_register *pkt)
{
    viodbg(HS, "GOT DRING_REG NACK ident[%llx] "
           "ndesc[%u] dsz[%u] opt[0x%x] ncookies[%u]\n",
           (unsigned long long) pkt->dring_ident,
           pkt->num_descr, pkt->descr_size, pkt->options,
           pkt->num_cookies);

    return handshake_failure(vio);
}

static int process_dreg(struct vio_driver_state *vio,
            struct vio_dring_register *pkt)
{
    if (!(vio->hs_state & VIO_HS_GOTVERS))
        return handshake_failure(vio);

    switch (pkt->tag.stype) {
    case VIO_SUBTYPE_INFO:
        return process_dreg_info(vio, pkt);

    case VIO_SUBTYPE_ACK:
        return process_dreg_ack(vio, pkt);

    case VIO_SUBTYPE_NACK:
        return process_dreg_nack(vio, pkt);

    default:
        return handshake_failure(vio);
    }
}

static int process_dunreg(struct vio_driver_state *vio,
              struct vio_dring_unregister *pkt)
{
    struct vio_dring_state *dr = &vio->drings[VIO_DRIVER_RX_RING];

    viodbg(HS, "GOT DRING_UNREG\n");

    if (pkt->dring_ident != dr->ident)
        return 0;

    vio->dr_state &= ~VIO_DR_STATE_RXREG;

    memset(dr, 0, sizeof(*dr));

    kfree(vio->desc_buf);
    vio->desc_buf = NULL;
    vio->desc_buf_len = 0;

    return 0;
}

static int process_rdx_info(struct vio_driver_state *vio, struct vio_rdx *pkt)
{
    viodbg(HS, "GOT RDX INFO\n");

    pkt->tag.stype = VIO_SUBTYPE_ACK;
    viodbg(HS, "SEND RDX ACK\n");
    if (send_ctrl(vio, &pkt->tag, sizeof(*pkt)) < 0)
        return handshake_failure(vio);

    vio->hs_state |= VIO_HS_SENT_RDX_ACK;
    return 0;
}

static int process_rdx_ack(struct vio_driver_state *vio, struct vio_rdx *pkt)
{
    viodbg(HS, "GOT RDX ACK\n");

    if (!(vio->hs_state & VIO_HS_SENT_RDX))
        return handshake_failure(vio);

    vio->hs_state |= VIO_HS_GOT_RDX_ACK;
    return 0;
}

static int process_rdx_nack(struct vio_driver_state *vio, struct vio_rdx *pkt)
{
    viodbg(HS, "GOT RDX NACK\n");

    return handshake_failure(vio);
}

static int process_rdx(struct vio_driver_state *vio, struct vio_rdx *pkt)
{
    if (!all_drings_registered(vio))
        handshake_failure(vio);

    switch (pkt->tag.stype) {
    case VIO_SUBTYPE_INFO:
        return process_rdx_info(vio, pkt);

    case VIO_SUBTYPE_ACK:
        return process_rdx_ack(vio, pkt);

    case VIO_SUBTYPE_NACK:
        return process_rdx_nack(vio, pkt);

    default:
        return handshake_failure(vio);
    }
}

int vio_control_pkt_engine(struct vio_driver_state *vio, void *pkt)
{
    struct vio_msg_tag *tag = pkt;
    u8 prev_state = vio->hs_state;
    int err;

    switch (tag->stype_env) {
    case VIO_VER_INFO:
        err = process_ver(vio, pkt);
        break;

    case VIO_ATTR_INFO:
        err = process_attr(vio, pkt);
        break;

    case VIO_DRING_REG:
        err = process_dreg(vio, pkt);
        break;

    case VIO_DRING_UNREG:
        err = process_dunreg(vio, pkt);
        break;

    case VIO_RDX:
        err = process_rdx(vio, pkt);
        break;

    default:
        err = process_unknown(vio, pkt);
        break;
    }
    if (!err &&
        vio->hs_state != prev_state &&
        (vio->hs_state & VIO_HS_COMPLETE))
        vio->ops->handshake_complete(vio);

    return err;
}
EXPORT_SYMBOL(vio_control_pkt_engine);

void vio_conn_reset(struct vio_driver_state *vio)
{
}
EXPORT_SYMBOL(vio_conn_reset);

/* The issue is that the Solaris virtual disk server just mirrors the
 * SID values it gets from the client peer.  So we work around that
 * here in vio_{validate,send}_sid() so that the drivers don't need
 * to be aware of this crap.
 */
int vio_validate_sid(struct vio_driver_state *vio, struct vio_msg_tag *tp)
{
    u32 sid;

    /* Always let VERSION+INFO packets through unchecked, they
     * define the new SID.
     */
    if (tp->type == VIO_TYPE_CTRL &&
        tp->stype == VIO_SUBTYPE_INFO &&
        tp->stype_env == VIO_VER_INFO)
        return 0;

    /* Ok, now figure out which SID to use.  */
    switch (vio->dev_class) {
    case VDEV_NETWORK:
    case VDEV_NETWORK_SWITCH:
    case VDEV_DISK_SERVER:
    default:
        sid = vio->_peer_sid;
        break;

    case VDEV_DISK:
        sid = vio->_local_sid;
        break;
    }

    if (sid == tp->sid)
        return 0;
    viodbg(DATA, "BAD SID tag->sid[%08x] peer_sid[%08x] local_sid[%08x]\n",
           tp->sid, vio->_peer_sid, vio->_local_sid);
    return -EINVAL;
}
EXPORT_SYMBOL(vio_validate_sid);

u32 vio_send_sid(struct vio_driver_state *vio)
{
    switch (vio->dev_class) {
    case VDEV_NETWORK:
    case VDEV_NETWORK_SWITCH:
    case VDEV_DISK:
    default:
        return vio->_local_sid;

    case VDEV_DISK_SERVER:
        return vio->_peer_sid;
    }
}
EXPORT_SYMBOL(vio_send_sid);

int vio_ldc_alloc(struct vio_driver_state *vio,
             struct ldc_channel_config *base_cfg,
             void *event_arg)
{
    struct ldc_channel_config cfg = *base_cfg;
    struct ldc_channel *lp;

    cfg.tx_irq = vio->vdev->tx_irq;
    cfg.rx_irq = vio->vdev->rx_irq;

    lp = ldc_alloc(vio->vdev->channel_id, &cfg, event_arg);
    if (IS_ERR(lp))
        return PTR_ERR(lp);

    vio->lp = lp;

    return 0;
}
EXPORT_SYMBOL(vio_ldc_alloc);

void vio_ldc_free(struct vio_driver_state *vio)
{
    ldc_free(vio->lp);
    vio->lp = NULL;

    kfree(vio->desc_buf);
    vio->desc_buf = NULL;
    vio->desc_buf_len = 0;
}
EXPORT_SYMBOL(vio_ldc_free);

void vio_port_up(struct vio_driver_state *vio)
{
    unsigned long flags;
    int err, state;

    spin_lock_irqsave(&vio->lock, flags);

    state = ldc_state(vio->lp);

    err = 0;
    if (state == LDC_STATE_INIT) {
        err = ldc_bind(vio->lp, vio->name);
        if (err)
            printk(KERN_WARNING "%s: Port %lu bind failed, "
                   "err=%d\n",
                   vio->name, vio->vdev->channel_id, err);
    }

    if (!err) {
        err = ldc_connect(vio->lp);
        if (err)
            printk(KERN_WARNING "%s: Port %lu connect failed, "
                   "err=%d\n",
                   vio->name, vio->vdev->channel_id, err);
    }
    if (err) {
        unsigned long expires = jiffies + HZ;

        expires = round_jiffies(expires);
        mod_timer(&vio->timer, expires);
    }

    spin_unlock_irqrestore(&vio->lock, flags);
}
EXPORT_SYMBOL(vio_port_up);

static void vio_port_timer(unsigned long _arg)
{
    struct vio_driver_state *vio = (struct vio_driver_state *) _arg;

    vio_port_up(vio);
}

int vio_driver_init(struct vio_driver_state *vio, struct vio_dev *vdev,
            u8 dev_class, struct vio_version *ver_table,
            int ver_table_size, struct vio_driver_ops *ops,
            char *name)
{
    switch (dev_class) {
    case VDEV_NETWORK:
    case VDEV_NETWORK_SWITCH:
    case VDEV_DISK:
    case VDEV_DISK_SERVER:
        break;

    default:
        return -EINVAL;
    }

    if (!ops->send_attr ||
        !ops->handle_attr ||
        !ops->handshake_complete)
        return -EINVAL;

    if (!ver_table || ver_table_size < 0)
        return -EINVAL;

    if (!name)
        return -EINVAL;

    spin_lock_init(&vio->lock);

    vio->name = name;

    vio->dev_class = dev_class;
    vio->vdev = vdev;

    vio->ver_table = ver_table;
    vio->ver_table_entries = ver_table_size;

    vio->ops = ops;

    setup_timer(&vio->timer, vio_port_timer, (unsigned long) vio);

    return 0;
}
EXPORT_SYMBOL(vio_driver_init);