Merge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6] / drivers / infiniband / hw / ipath / ipath_intr.c

/*
 * Copyright (c) 2006, 2007, 2008 QLogic Corporation. All rights reserved.
 * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/pci.h>
#include <linux/delay.h>

#include "ipath_kernel.h"
#include "ipath_verbs.h"
#include "ipath_common.h"


/*
 * Called when we might have an error that is specific to a particular
 * PIO buffer, and may need to cancel that buffer, so it can be re-used.
 */
void ipath_disarm_senderrbufs(struct ipath_devdata *dd)
{
        u32 piobcnt;
        unsigned long sbuf[4];
        /*
         * it's possible that sendbuffererror could have bits set; might
         * have already done this as a result of hardware error handling
         */
        piobcnt = dd->ipath_piobcnt2k + dd->ipath_piobcnt4k;
        /* read these before writing errorclear */
        sbuf[0] = ipath_read_kreg64(
                dd, dd->ipath_kregs->kr_sendbuffererror);
        sbuf[1] = ipath_read_kreg64(
                dd, dd->ipath_kregs->kr_sendbuffererror + 1);
        if (piobcnt > 128)
                sbuf[2] = ipath_read_kreg64(
                        dd, dd->ipath_kregs->kr_sendbuffererror + 2);
        if (piobcnt > 192)
                sbuf[3] = ipath_read_kreg64(
                        dd, dd->ipath_kregs->kr_sendbuffererror + 3);
        else
                sbuf[3] = 0;

        if (sbuf[0] || sbuf[1] || (piobcnt > 128 && (sbuf[2] || sbuf[3]))) {
                int i;
                if (ipath_debug & (__IPATH_PKTDBG|__IPATH_DBG) &&
                        dd->ipath_lastcancel > jiffies) {
                        __IPATH_DBG_WHICH(__IPATH_PKTDBG|__IPATH_DBG,
                                          "SendbufErrs %lx %lx", sbuf[0],
                                          sbuf[1]);
                        if (ipath_debug & __IPATH_PKTDBG && piobcnt > 128)
                                printk(" %lx %lx ", sbuf[2], sbuf[3]);
                        printk("\n");
                }

                for (i = 0; i < piobcnt; i++)
                        if (test_bit(i, sbuf))
                                ipath_disarm_piobufs(dd, i, 1);
                /* ignore armlaunch errs for a bit */
                dd->ipath_lastcancel = jiffies+3;
        }
}


/* These are all rcv-related errors which we want to count for stats */
#define E_SUM_PKTERRS \
        (INFINIPATH_E_RHDRLEN | INFINIPATH_E_RBADTID | \
         INFINIPATH_E_RBADVERSION | INFINIPATH_E_RHDR | \
         INFINIPATH_E_RLONGPKTLEN | INFINIPATH_E_RSHORTPKTLEN | \
         INFINIPATH_E_RMAXPKTLEN | INFINIPATH_E_RMINPKTLEN | \
         INFINIPATH_E_RFORMATERR | INFINIPATH_E_RUNSUPVL | \
         INFINIPATH_E_RUNEXPCHAR | INFINIPATH_E_REBP)

/* These are all send-related errors which we want to count for stats */
#define E_SUM_ERRS \
        (INFINIPATH_E_SPIOARMLAUNCH | INFINIPATH_E_SUNEXPERRPKTNUM | \
         INFINIPATH_E_SDROPPEDDATAPKT | INFINIPATH_E_SDROPPEDSMPPKT | \
         INFINIPATH_E_SMAXPKTLEN | INFINIPATH_E_SUNSUPVL | \
         INFINIPATH_E_SMINPKTLEN | INFINIPATH_E_SPKTLEN | \
         INFINIPATH_E_INVALIDADDR)

/*
 * this is similar to E_SUM_ERRS, but can't ignore armlaunch, don't ignore
 * errors not related to freeze and cancelling buffers.  Can't ignore
 * armlaunch because could get more while still cleaning up, and need
 * to cancel those as they happen.
 */
#define E_SPKT_ERRS_IGNORE \
         (INFINIPATH_E_SDROPPEDDATAPKT | INFINIPATH_E_SDROPPEDSMPPKT | \
         INFINIPATH_E_SMAXPKTLEN | INFINIPATH_E_SMINPKTLEN | \
         INFINIPATH_E_SPKTLEN)

/*
 * these are errors that can occur when the link changes state while
 * a packet is being sent or received.  This doesn't cover things
 * like EBP or VCRC that can be the result of a sending having the
 * link change state, so we receive a "known bad" packet.
 */
#define E_SUM_LINK_PKTERRS \
        (INFINIPATH_E_SDROPPEDDATAPKT | INFINIPATH_E_SDROPPEDSMPPKT | \
         INFINIPATH_E_SMINPKTLEN | INFINIPATH_E_SPKTLEN | \
         INFINIPATH_E_RSHORTPKTLEN | INFINIPATH_E_RMINPKTLEN | \
         INFINIPATH_E_RUNEXPCHAR)

static u64 handle_e_sum_errs(struct ipath_devdata *dd, ipath_err_t errs)
{
        u64 ignore_this_time = 0;

        ipath_disarm_senderrbufs(dd);
        if ((errs & E_SUM_LINK_PKTERRS) &&
            !(dd->ipath_flags & IPATH_LINKACTIVE)) {
                /*
                 * This can happen when SMA is trying to bring the link
                 * up, but the IB link changes state at the "wrong" time.
                 * The IB logic then complains that the packet isn't
                 * valid.  We don't want to confuse people, so we just
                 * don't print them, except at debug
                 */
                ipath_dbg("Ignoring packet errors %llx, because link not "
                          "ACTIVE\n", (unsigned long long) errs);
                ignore_this_time = errs & E_SUM_LINK_PKTERRS;
        }

        return ignore_this_time;
}

/* generic hw error messages... */
#define INFINIPATH_HWE_TXEMEMPARITYERR_MSG(a) \
        { \
                .mask = ( INFINIPATH_HWE_TXEMEMPARITYERR_##a <<    \
                          INFINIPATH_HWE_TXEMEMPARITYERR_SHIFT ),   \
                .msg = "TXE " #a " Memory Parity"            \
        }
#define INFINIPATH_HWE_RXEMEMPARITYERR_MSG(a) \
        { \
                .mask = ( INFINIPATH_HWE_RXEMEMPARITYERR_##a <<    \
                          INFINIPATH_HWE_RXEMEMPARITYERR_SHIFT ),   \
                .msg = "RXE " #a " Memory Parity"            \
        }

static const struct ipath_hwerror_msgs ipath_generic_hwerror_msgs[] = {
        INFINIPATH_HWE_MSG(IBCBUSFRSPCPARITYERR, "IPATH2IB Parity"),
        INFINIPATH_HWE_MSG(IBCBUSTOSPCPARITYERR, "IB2IPATH Parity"),

        INFINIPATH_HWE_TXEMEMPARITYERR_MSG(PIOBUF),
        INFINIPATH_HWE_TXEMEMPARITYERR_MSG(PIOPBC),
        INFINIPATH_HWE_TXEMEMPARITYERR_MSG(PIOLAUNCHFIFO),

        INFINIPATH_HWE_RXEMEMPARITYERR_MSG(RCVBUF),
        INFINIPATH_HWE_RXEMEMPARITYERR_MSG(LOOKUPQ),
        INFINIPATH_HWE_RXEMEMPARITYERR_MSG(EAGERTID),
        INFINIPATH_HWE_RXEMEMPARITYERR_MSG(EXPTID),
        INFINIPATH_HWE_RXEMEMPARITYERR_MSG(FLAGBUF),
        INFINIPATH_HWE_RXEMEMPARITYERR_MSG(DATAINFO),
        INFINIPATH_HWE_RXEMEMPARITYERR_MSG(HDRINFO),
};

/**
 * ipath_format_hwmsg - format a single hwerror message
 * @msg message buffer
 * @msgl length of message buffer
 * @hwmsg message to add to message buffer
 */
static void ipath_format_hwmsg(char *msg, size_t msgl, const char *hwmsg)
{
        strlcat(msg, "[", msgl);
        strlcat(msg, hwmsg, msgl);
        strlcat(msg, "]", msgl);
}

/**
 * ipath_format_hwerrors - format hardware error messages for display
 * @hwerrs hardware errors bit vector
 * @hwerrmsgs hardware error descriptions
 * @nhwerrmsgs number of hwerrmsgs
 * @msg message buffer
 * @msgl message buffer length
 */
void ipath_format_hwerrors(u64 hwerrs,
                           const struct ipath_hwerror_msgs *hwerrmsgs,
                           size_t nhwerrmsgs,
                           char *msg, size_t msgl)
{
        int i;
        const int glen =
            sizeof(ipath_generic_hwerror_msgs) /
            sizeof(ipath_generic_hwerror_msgs[0]);

        for (i=0; i<glen; i++) {
                if (hwerrs & ipath_generic_hwerror_msgs[i].mask) {
                        ipath_format_hwmsg(msg, msgl,
                                           ipath_generic_hwerror_msgs[i].msg);
                }
        }

        for (i=0; i<nhwerrmsgs; i++) {
                if (hwerrs & hwerrmsgs[i].mask) {
                        ipath_format_hwmsg(msg, msgl, hwerrmsgs[i].msg);
                }
        }
}

/* return the strings for the most common link states */
static char *ib_linkstate(struct ipath_devdata *dd, u64 ibcs)
{
        char *ret;
        u32 state;

        state = ipath_ib_state(dd, ibcs);
        if (state == dd->ib_init)
                ret = "Init";
        else if (state == dd->ib_arm)
                ret = "Arm";
        else if (state == dd->ib_active)
                ret = "Active";
        else
                ret = "Down";
        return ret;
}

void signal_ib_event(struct ipath_devdata *dd, enum ib_event_type ev)
{
        struct ib_event event;

        event.device = &dd->verbs_dev->ibdev;
        event.element.port_num = 1;
        event.event = ev;
        ib_dispatch_event(&event);
}

static void handle_e_ibstatuschanged(struct ipath_devdata *dd,
                                     ipath_err_t errs)
{
        u32 ltstate, lstate, ibstate, lastlstate;
        u32 init = dd->ib_init;
        u32 arm = dd->ib_arm;
        u32 active = dd->ib_active;
        const u64 ibcs = ipath_read_kreg64(dd, dd->ipath_kregs->kr_ibcstatus);

        lstate = ipath_ib_linkstate(dd, ibcs); /* linkstate */
        ibstate = ipath_ib_state(dd, ibcs);
        /* linkstate at last interrupt */
        lastlstate = ipath_ib_linkstate(dd, dd->ipath_lastibcstat);
        ltstate = ipath_ib_linktrstate(dd, ibcs); /* linktrainingtate */

        /*
         * Since going into a recovery state causes the link state to go
         * down and since recovery is transitory, it is better if we "miss"
         * ever seeing the link training state go into recovery (i.e.,
         * ignore this transition for link state special handling purposes)
         * without even updating ipath_lastibcstat.
         */
        if ((ltstate == INFINIPATH_IBCS_LT_STATE_RECOVERRETRAIN) ||
            (ltstate == INFINIPATH_IBCS_LT_STATE_RECOVERWAITRMT) ||
            (ltstate == INFINIPATH_IBCS_LT_STATE_RECOVERIDLE))
                goto done;

        /*
         * if linkstate transitions into INIT from any of the various down
         * states, or if it transitions from any of the up (INIT or better)
         * states into any of the down states (except link recovery), then
         * call the chip-specific code to take appropriate actions.
         */
        if (lstate >= INFINIPATH_IBCS_L_STATE_INIT &&
                lastlstate == INFINIPATH_IBCS_L_STATE_DOWN) {
                /* transitioned to UP */
                if (dd->ipath_f_ib_updown(dd, 1, ibcs)) {
                        /* link came up, so we must no longer be disabled */
                        dd->ipath_flags &= ~IPATH_IB_LINK_DISABLED;
                        ipath_cdbg(LINKVERB, "LinkUp handled, skipped\n");
                        goto skip_ibchange; /* chip-code handled */
                }
        } else if ((lastlstate >= INFINIPATH_IBCS_L_STATE_INIT ||
                (dd->ipath_flags & IPATH_IB_FORCE_NOTIFY)) &&
                ltstate <= INFINIPATH_IBCS_LT_STATE_CFGWAITRMT &&
                ltstate != INFINIPATH_IBCS_LT_STATE_LINKUP) {
                int handled;
                handled = dd->ipath_f_ib_updown(dd, 0, ibcs);
                dd->ipath_flags &= ~IPATH_IB_FORCE_NOTIFY;
                if (handled) {
                        ipath_cdbg(LINKVERB, "LinkDown handled, skipped\n");
                        goto skip_ibchange; /* chip-code handled */
                }
        }

        /*
         * Significant enough to always print and get into logs, if it was
         * unexpected.  If it was a requested state change, we'll have
         * already cleared the flags, so we won't print this warning
         */
        if ((ibstate != arm && ibstate != active) &&
            (dd->ipath_flags & (IPATH_LINKARMED | IPATH_LINKACTIVE))) {
                dev_info(&dd->pcidev->dev, "Link state changed from %s "
                         "to %s\n", (dd->ipath_flags & IPATH_LINKARMED) ?
                         "ARM" : "ACTIVE", ib_linkstate(dd, ibcs));
        }

        if (ltstate == INFINIPATH_IBCS_LT_STATE_POLLACTIVE ||
            ltstate == INFINIPATH_IBCS_LT_STATE_POLLQUIET) {
                u32 lastlts;
                lastlts = ipath_ib_linktrstate(dd, dd->ipath_lastibcstat);
                /*
                 * Ignore cycling back and forth from Polling.Active to
                 * Polling.Quiet while waiting for the other end of the link
                 * to come up, except to try and decide if we are connected
                 * to a live IB device or not.  We will cycle back and
                 * forth between them if no cable is plugged in, the other
                 * device is powered off or disabled, etc.
                 */
                if (lastlts == INFINIPATH_IBCS_LT_STATE_POLLACTIVE ||
                    lastlts == INFINIPATH_IBCS_LT_STATE_POLLQUIET) {
                        if (!(dd->ipath_flags & IPATH_IB_AUTONEG_INPROG) &&
                             (++dd->ipath_ibpollcnt == 40)) {
                                dd->ipath_flags |= IPATH_NOCABLE;
                                *dd->ipath_statusp |=
                                        IPATH_STATUS_IB_NOCABLE;
                                ipath_cdbg(LINKVERB, "Set NOCABLE\n");
                        }
                        ipath_cdbg(LINKVERB, "POLL change to %s (%x)\n",
                                ipath_ibcstatus_str[ltstate], ibstate);
                        goto skip_ibchange;
                }
        }

        dd->ipath_ibpollcnt = 0; /* not poll*, now */
        ipath_stats.sps_iblink++;

        if (ibstate != init && dd->ipath_lastlinkrecov && ipath_linkrecovery) {
                u64 linkrecov;
                linkrecov = ipath_snap_cntr(dd,
                        dd->ipath_cregs->cr_iblinkerrrecovcnt);
                if (linkrecov != dd->ipath_lastlinkrecov) {
                        ipath_dbg("IB linkrecov up %Lx (%s %s) recov %Lu\n",
                                (unsigned long long) ibcs,
                                ib_linkstate(dd, ibcs),
                                ipath_ibcstatus_str[ltstate],
                                (unsigned long long) linkrecov);
                        /* and no more until active again */
                        dd->ipath_lastlinkrecov = 0;
                        ipath_set_linkstate(dd, IPATH_IB_LINKDOWN);
                        goto skip_ibchange;
                }
        }

        if (ibstate == init || ibstate == arm || ibstate == active) {
                *dd->ipath_statusp &= ~IPATH_STATUS_IB_NOCABLE;
                if (ibstate == init || ibstate == arm) {
                        *dd->ipath_statusp &= ~IPATH_STATUS_IB_READY;
                        if (dd->ipath_flags & IPATH_LINKACTIVE)
                                signal_ib_event(dd, IB_EVENT_PORT_ERR);
                }
                if (ibstate == arm) {
                        dd->ipath_flags |= IPATH_LINKARMED;
                        dd->ipath_flags &= ~(IPATH_LINKUNK |
                                IPATH_LINKINIT | IPATH_LINKDOWN |
                                IPATH_LINKACTIVE | IPATH_NOCABLE);
                        ipath_hol_down(dd);
                } else  if (ibstate == init) {
                        /*
                         * set INIT and DOWN.  Down is checked by
                         * most of the other code, but INIT is
                         * useful to know in a few places.
                         */
                        dd->ipath_flags |= IPATH_LINKINIT |
                                IPATH_LINKDOWN;
                        dd->ipath_flags &= ~(IPATH_LINKUNK |
                                IPATH_LINKARMED | IPATH_LINKACTIVE |
                                IPATH_NOCABLE);
                        ipath_hol_down(dd);
                } else {  /* active */
                        dd->ipath_lastlinkrecov = ipath_snap_cntr(dd,
                                dd->ipath_cregs->cr_iblinkerrrecovcnt);
                        *dd->ipath_statusp |=
                                IPATH_STATUS_IB_READY | IPATH_STATUS_IB_CONF;
                        dd->ipath_flags |= IPATH_LINKACTIVE;
                        dd->ipath_flags &= ~(IPATH_LINKUNK | IPATH_LINKINIT
                                | IPATH_LINKDOWN | IPATH_LINKARMED |
                                IPATH_NOCABLE);
                        if (dd->ipath_flags & IPATH_HAS_SEND_DMA)
                                ipath_restart_sdma(dd);
                        signal_ib_event(dd, IB_EVENT_PORT_ACTIVE);
                        /* LED active not handled in chip _f_updown */
                        dd->ipath_f_setextled(dd, lstate, ltstate);
                        ipath_hol_up(dd);
                }

                /*
                 * print after we've already done the work, so as not to
                 * delay the state changes and notifications, for debugging
                 */
                if (lstate == lastlstate)
                        ipath_cdbg(LINKVERB, "Unchanged from last: %s "
                                "(%x)\n", ib_linkstate(dd, ibcs), ibstate);
                else
                        ipath_cdbg(VERBOSE, "Unit %u: link up to %s %s (%x)\n",
                                  dd->ipath_unit, ib_linkstate(dd, ibcs),
                                  ipath_ibcstatus_str[ltstate],  ibstate);
        } else { /* down */
                if (dd->ipath_flags & IPATH_LINKACTIVE)
                        signal_ib_event(dd, IB_EVENT_PORT_ERR);
                dd->ipath_flags |= IPATH_LINKDOWN;
                dd->ipath_flags &= ~(IPATH_LINKUNK | IPATH_LINKINIT
                                     | IPATH_LINKACTIVE |
                                     IPATH_LINKARMED);
                *dd->ipath_statusp &= ~IPATH_STATUS_IB_READY;
                dd->ipath_lli_counter = 0;

                if (lastlstate != INFINIPATH_IBCS_L_STATE_DOWN)
                        ipath_cdbg(VERBOSE, "Unit %u link state down "
                                   "(state 0x%x), from %s\n",
                                   dd->ipath_unit, lstate,
                                   ib_linkstate(dd, dd->ipath_lastibcstat));
                else
                        ipath_cdbg(LINKVERB, "Unit %u link state changed "
                                   "to %s (0x%x) from down (%x)\n",
                                   dd->ipath_unit,
                                   ipath_ibcstatus_str[ltstate],
                                   ibstate, lastlstate);
        }

skip_ibchange:
        dd->ipath_lastibcstat = ibcs;
done:
        return;
}

static void handle_supp_msgs(struct ipath_devdata *dd,
                             unsigned supp_msgs, char *msg, u32 msgsz)
{
        /*
         * Print the message unless it's ibc status change only, which
         * happens so often we never want to count it.
         */
        if (dd->ipath_lasterror & ~INFINIPATH_E_IBSTATUSCHANGED) {
                int iserr;
                ipath_err_t mask;
                iserr = ipath_decode_err(dd, msg, msgsz,
                                         dd->ipath_lasterror &
                                         ~INFINIPATH_E_IBSTATUSCHANGED);

                mask = INFINIPATH_E_RRCVEGRFULL | INFINIPATH_E_RRCVHDRFULL |
                        INFINIPATH_E_PKTERRS | INFINIPATH_E_SDMADISABLED;

                /* if we're in debug, then don't mask SDMADISABLED msgs */
                if (ipath_debug & __IPATH_DBG)
                        mask &= ~INFINIPATH_E_SDMADISABLED;

                if (dd->ipath_lasterror & ~mask)
                        ipath_dev_err(dd, "Suppressed %u messages for "
                                      "fast-repeating errors (%s) (%llx)\n",
                                      supp_msgs, msg,
                                      (unsigned long long)
                                      dd->ipath_lasterror);
                else {
                        /*
                         * rcvegrfull and rcvhdrqfull are "normal", for some
                         * types of processes (mostly benchmarks) that send
                         * huge numbers of messages, while not processing
                         * them. So only complain about these at debug
                         * level.
                         */
                        if (iserr)
                                ipath_dbg("Suppressed %u messages for %s\n",
                                          supp_msgs, msg);
                        else
                                ipath_cdbg(ERRPKT,
                                        "Suppressed %u messages for %s\n",
                                          supp_msgs, msg);
                }
        }
}

static unsigned handle_frequent_errors(struct ipath_devdata *dd,
                                       ipath_err_t errs, char *msg,
                                       u32 msgsz, int *noprint)
{
        unsigned long nc;
        static unsigned long nextmsg_time;
        static unsigned nmsgs, supp_msgs;

        /*
         * Throttle back "fast" messages to no more than 10 per 5 seconds.
         * This isn't perfect, but it's a reasonable heuristic. If we get
         * more than 10, give a 6x longer delay.
         */
        nc = jiffies;
        if (nmsgs > 10) {
                if (time_before(nc, nextmsg_time)) {
                        *noprint = 1;
                        if (!supp_msgs++)
                                nextmsg_time = nc + HZ * 3;
                }
                else if (supp_msgs) {
                        handle_supp_msgs(dd, supp_msgs, msg, msgsz);
                        supp_msgs = 0;
                        nmsgs = 0;
                }
        }
        else if (!nmsgs++ || time_after(nc, nextmsg_time))
                nextmsg_time = nc + HZ / 2;

        return supp_msgs;
}

static void handle_sdma_errors(struct ipath_devdata *dd, ipath_err_t errs)
{
        unsigned long flags;
        int expected;

        if (ipath_debug & __IPATH_DBG) {
                char msg[128];
                ipath_decode_err(dd, msg, sizeof msg, errs &
                        INFINIPATH_E_SDMAERRS);
                ipath_dbg("errors %lx (%s)\n", (unsigned long)errs, msg);
        }
        if (ipath_debug & __IPATH_VERBDBG) {
                unsigned long tl, hd, status, lengen;
                tl = ipath_read_kreg64(dd, dd->ipath_kregs->kr_senddmatail);
                hd = ipath_read_kreg64(dd, dd->ipath_kregs->kr_senddmahead);
                status = ipath_read_kreg64(dd
                        , dd->ipath_kregs->kr_senddmastatus);
                lengen = ipath_read_kreg64(dd,
                        dd->ipath_kregs->kr_senddmalengen);
                ipath_cdbg(VERBOSE, "sdma tl 0x%lx hd 0x%lx status 0x%lx "
                        "lengen 0x%lx\n", tl, hd, status, lengen);
        }

        spin_lock_irqsave(&dd->ipath_sdma_lock, flags);
        __set_bit(IPATH_SDMA_DISABLED, &dd->ipath_sdma_status);
        expected = test_bit(IPATH_SDMA_ABORTING, &dd->ipath_sdma_status);
        spin_unlock_irqrestore(&dd->ipath_sdma_lock, flags);
        if (!expected)
                ipath_cancel_sends(dd, 1);
}

static void handle_sdma_intr(struct ipath_devdata *dd, u64 istat)
{
        unsigned long flags;
        int expected;

        if ((istat & INFINIPATH_I_SDMAINT) &&
            !test_bit(IPATH_SDMA_SHUTDOWN, &dd->ipath_sdma_status))
                ipath_sdma_intr(dd);

        if (istat & INFINIPATH_I_SDMADISABLED) {
                expected = test_bit(IPATH_SDMA_ABORTING,
                        &dd->ipath_sdma_status);
                ipath_dbg("%s SDmaDisabled intr\n",
                        expected ? "expected" : "unexpected");
                spin_lock_irqsave(&dd->ipath_sdma_lock, flags);
                __set_bit(IPATH_SDMA_DISABLED, &dd->ipath_sdma_status);
                spin_unlock_irqrestore(&dd->ipath_sdma_lock, flags);
                if (!expected)
                        ipath_cancel_sends(dd, 1);
                if (!test_bit(IPATH_SDMA_SHUTDOWN, &dd->ipath_sdma_status))
                        tasklet_hi_schedule(&dd->ipath_sdma_abort_task);
        }
}

static int handle_hdrq_full(struct ipath_devdata *dd)
{
        int chkerrpkts = 0;
        u32 hd, tl;
        u32 i;

        ipath_stats.sps_hdrqfull++;
        for (i = 0; i < dd->ipath_cfgports; i++) {
                struct ipath_portdata *pd = dd->ipath_pd[i];

                if (i == 0) {
                        /*
                         * For kernel receive queues, we just want to know
                         * if there are packets in the queue that we can
                         * process.
                         */
                        if (pd->port_head != ipath_get_hdrqtail(pd))
                                chkerrpkts |= 1 << i;
                        continue;
                }

                /* Skip if user context is not open */
                if (!pd || !pd->port_cnt)
                        continue;

                /* Don't report the same point multiple times. */
                if (dd->ipath_flags & IPATH_NODMA_RTAIL)
                        tl = ipath_read_ureg32(dd, ur_rcvhdrtail, i);
                else
                        tl = ipath_get_rcvhdrtail(pd);
                if (tl == pd->port_lastrcvhdrqtail)
                        continue;

                hd = ipath_read_ureg32(dd, ur_rcvhdrhead, i);
                if (hd == (tl + 1) || (!hd && tl == dd->ipath_hdrqlast)) {
                        pd->port_lastrcvhdrqtail = tl;
                        pd->port_hdrqfull++;
                        /* flush hdrqfull so that poll() sees it */
                        wmb();
                        wake_up_interruptible(&pd->port_wait);
                }
        }

        return chkerrpkts;
}

static int handle_errors(struct ipath_devdata *dd, ipath_err_t errs)
{
        char msg[128];
        u64 ignore_this_time = 0;
        u64 iserr = 0;
        int chkerrpkts = 0, noprint = 0;
        unsigned supp_msgs;
        int log_idx;

        /*
         * don't report errors that are masked, either at init
         * (not set in ipath_errormask), or temporarily (set in
         * ipath_maskederrs)
         */
        errs &= dd->ipath_errormask & ~dd->ipath_maskederrs;

        supp_msgs = handle_frequent_errors(dd, errs, msg, (u32)sizeof msg,
                &noprint);

        /* do these first, they are most important */
        if (errs & INFINIPATH_E_HARDWARE) {
                /* reuse same msg buf */
                dd->ipath_f_handle_hwerrors(dd, msg, sizeof msg);
        } else {
                u64 mask;
                for (log_idx = 0; log_idx < IPATH_EEP_LOG_CNT; ++log_idx) {
                        mask = dd->ipath_eep_st_masks[log_idx].errs_to_log;
                        if (errs & mask)
                                ipath_inc_eeprom_err(dd, log_idx, 1);
                }
        }

        if (errs & INFINIPATH_E_SDMAERRS)
                handle_sdma_errors(dd, errs);

        if (!noprint && (errs & ~dd->ipath_e_bitsextant))
                ipath_dev_err(dd, "error interrupt with unknown errors "
                              "%llx set\n", (unsigned long long)
                              (errs & ~dd->ipath_e_bitsextant));

        if (errs & E_SUM_ERRS)
                ignore_this_time = handle_e_sum_errs(dd, errs);
        else if ((errs & E_SUM_LINK_PKTERRS) &&
            !(dd->ipath_flags & IPATH_LINKACTIVE)) {
                /*
                 * This can happen when SMA is trying to bring the link
                 * up, but the IB link changes state at the "wrong" time.
                 * The IB logic then complains that the packet isn't
                 * valid.  We don't want to confuse people, so we just
                 * don't print them, except at debug
                 */
                ipath_dbg("Ignoring packet errors %llx, because link not "
                          "ACTIVE\n", (unsigned long long) errs);
                ignore_this_time = errs & E_SUM_LINK_PKTERRS;
        }

        if (supp_msgs == 250000) {
                int s_iserr;
                /*
                 * It's not entirely reasonable assuming that the errors set
                 * in the last clear period are all responsible for the
                 * problem, but the alternative is to assume it's the only
                 * ones on this particular interrupt, which also isn't great
                 */
                dd->ipath_maskederrs |= dd->ipath_lasterror | errs;

                dd->ipath_errormask &= ~dd->ipath_maskederrs;
                ipath_write_kreg(dd, dd->ipath_kregs->kr_errormask,
                                 dd->ipath_errormask);
                s_iserr = ipath_decode_err(dd, msg, sizeof msg,
                                           dd->ipath_maskederrs);

                if (dd->ipath_maskederrs &
                    ~(INFINIPATH_E_RRCVEGRFULL |
                      INFINIPATH_E_RRCVHDRFULL | INFINIPATH_E_PKTERRS))
                        ipath_dev_err(dd, "Temporarily disabling "
                            "error(s) %llx reporting; too frequent (%s)\n",
                                (unsigned long long) dd->ipath_maskederrs,
                                msg);
                else {
                        /*
                         * rcvegrfull and rcvhdrqfull are "normal",
                         * for some types of processes (mostly benchmarks)
                         * that send huge numbers of messages, while not
                         * processing them.  So only complain about
                         * these at debug level.
                         */
                        if (s_iserr)
                                ipath_dbg("Temporarily disabling reporting "
                                    "too frequent queue full errors (%s)\n",
                                    msg);
                        else
                                ipath_cdbg(ERRPKT,
                                    "Temporarily disabling reporting too"
                                    " frequent packet errors (%s)\n",
                                    msg);
                }

                /*
                 * Re-enable the masked errors after around 3 minutes.  in
                 * ipath_get_faststats().  If we have a series of fast
                 * repeating but different errors, the interval will keep
                 * stretching out, but that's OK, as that's pretty
                 * catastrophic.
                 */
                dd->ipath_unmasktime = jiffies + HZ * 180;
        }

        ipath_write_kreg(dd, dd->ipath_kregs->kr_errorclear, errs);
        if (ignore_this_time)
                errs &= ~ignore_this_time;
        if (errs & ~dd->ipath_lasterror) {
                errs &= ~dd->ipath_lasterror;
                /* never suppress duplicate hwerrors or ibstatuschange */
                dd->ipath_lasterror |= errs &
                        ~(INFINIPATH_E_HARDWARE |
                          INFINIPATH_E_IBSTATUSCHANGED);
        }

        if (errs & INFINIPATH_E_SENDSPECIALTRIGGER) {
                dd->ipath_spectriggerhit++;
                ipath_dbg("%lu special trigger hits\n",
                        dd->ipath_spectriggerhit);
        }

        /* likely due to cancel; so suppress message unless verbose */
        if ((errs & (INFINIPATH_E_SPKTLEN | INFINIPATH_E_SPIOARMLAUNCH)) &&
                dd->ipath_lastcancel > jiffies) {
                /* armlaunch takes precedence; it often causes both. */
                ipath_cdbg(VERBOSE,
                        "Suppressed %s error (%llx) after sendbuf cancel\n",
                        (errs &  INFINIPATH_E_SPIOARMLAUNCH) ?
                        "armlaunch" : "sendpktlen", (unsigned long long)errs);
                errs &= ~(INFINIPATH_E_SPIOARMLAUNCH | INFINIPATH_E_SPKTLEN);
        }

        if (!errs)
                return 0;

        if (!noprint) {
                ipath_err_t mask;
                /*
                 * The ones we mask off are handled specially below
                 * or above.  Also mask SDMADISABLED by default as it
                 * is too chatty.
                 */
                mask = INFINIPATH_E_IBSTATUSCHANGED |
                        INFINIPATH_E_RRCVEGRFULL | INFINIPATH_E_RRCVHDRFULL |
                        INFINIPATH_E_HARDWARE | INFINIPATH_E_SDMADISABLED;

                /* if we're in debug, then don't mask SDMADISABLED msgs */
                if (ipath_debug & __IPATH_DBG)
                        mask &= ~INFINIPATH_E_SDMADISABLED;

                ipath_decode_err(dd, msg, sizeof msg, errs & ~mask);
        } else
                /* so we don't need if (!noprint) at strlcat's below */
                *msg = 0;

        if (errs & E_SUM_PKTERRS) {
                ipath_stats.sps_pkterrs++;
                chkerrpkts = 1;
        }
        if (errs & E_SUM_ERRS)
                ipath_stats.sps_errs++;

        if (errs & (INFINIPATH_E_RICRC | INFINIPATH_E_RVCRC)) {
                ipath_stats.sps_crcerrs++;
                chkerrpkts = 1;
        }
        iserr = errs & ~(E_SUM_PKTERRS | INFINIPATH_E_PKTERRS);


        /*
         * We don't want to print these two as they happen, or we can make
         * the situation even worse, because it takes so long to print
         * messages to serial consoles.  Kernel ports get printed from
         * fast_stats, no more than every 5 seconds, user ports get printed
         * on close
         */
        if (errs & INFINIPATH_E_RRCVHDRFULL)
                chkerrpkts |= handle_hdrq_full(dd);
        if (errs & INFINIPATH_E_RRCVEGRFULL) {
                struct ipath_portdata *pd = dd->ipath_pd[0];

                /*
                 * since this is of less importance and not likely to
                 * happen without also getting hdrfull, only count
                 * occurrences; don't check each port (or even the kernel
                 * vs user)
                 */
                ipath_stats.sps_etidfull++;
                if (pd->port_head != ipath_get_hdrqtail(pd))
                        chkerrpkts |= 1;
        }

        /*
         * do this before IBSTATUSCHANGED, in case both bits set in a single
         * interrupt; we want the STATUSCHANGE to "win", so we do our
         * internal copy of state machine correctly
         */
        if (errs & INFINIPATH_E_RIBLOSTLINK) {
                /*
                 * force through block below
                 */
                errs |= INFINIPATH_E_IBSTATUSCHANGED;
                ipath_stats.sps_iblink++;
                dd->ipath_flags |= IPATH_LINKDOWN;
                dd->ipath_flags &= ~(IPATH_LINKUNK | IPATH_LINKINIT
                                     | IPATH_LINKARMED | IPATH_LINKACTIVE);
                *dd->ipath_statusp &= ~IPATH_STATUS_IB_READY;

                ipath_dbg("Lost link, link now down (%s)\n",
                        ipath_ibcstatus_str[ipath_read_kreg64(dd,
                        dd->ipath_kregs->kr_ibcstatus) & 0xf]);
        }
        if (errs & INFINIPATH_E_IBSTATUSCHANGED)
                handle_e_ibstatuschanged(dd, errs);

        if (errs & INFINIPATH_E_RESET) {
                if (!noprint)
                        ipath_dev_err(dd, "Got reset, requires re-init "
                                      "(unload and reload driver)\n");
                dd->ipath_flags &= ~IPATH_INITTED;      /* needs re-init */
                /* mark as having had error */
                *dd->ipath_statusp |= IPATH_STATUS_HWERROR;
                *dd->ipath_statusp &= ~IPATH_STATUS_IB_CONF;
        }

        if (!noprint && *msg) {
                if (iserr)
                        ipath_dev_err(dd, "%s error\n", msg);
        }
        if (dd->ipath_state_wanted & dd->ipath_flags) {
                ipath_cdbg(VERBOSE, "driver wanted state %x, iflags now %x, "
                           "waking\n", dd->ipath_state_wanted,
                           dd->ipath_flags);
                wake_up_interruptible(&ipath_state_wait);
        }

        return chkerrpkts;
}

/*
 * try to cleanup as much as possible for anything that might have gone
 * wrong while in freeze mode, such as pio buffers being written by user
 * processes (causing armlaunch), send errors due to going into freeze mode,
 * etc., and try to avoid causing extra interrupts while doing so.
 * Forcibly update the in-memory pioavail register copies after cleanup
 * because the chip won't do it while in freeze mode (the register values
 * themselves are kept correct).
 * Make sure that we don't lose any important interrupts by using the chip
 * feature that says that writing 0 to a bit in *clear that is set in
 * *status will cause an interrupt to be generated again (if allowed by
 * the *mask value).
 */
void ipath_clear_freeze(struct ipath_devdata *dd)
{
        /* disable error interrupts, to avoid confusion */
        ipath_write_kreg(dd, dd->ipath_kregs->kr_errormask, 0ULL);

        /* also disable interrupts; errormask is sometimes overwriten */
        ipath_write_kreg(dd, dd->ipath_kregs->kr_intmask, 0ULL);

        ipath_cancel_sends(dd, 1);

        /* clear the freeze, and be sure chip saw it */
        ipath_write_kreg(dd, dd->ipath_kregs->kr_control,
                         dd->ipath_control);
        ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);

        /* force in-memory update now we are out of freeze */
        ipath_force_pio_avail_update(dd);

        /*
         * force new interrupt if any hwerr, error or interrupt bits are
         * still set, and clear "safe" send packet errors related to freeze
         * and cancelling sends.  Re-enable error interrupts before possible
         * force of re-interrupt on pending interrupts.
         */
        ipath_write_kreg(dd, dd->ipath_kregs->kr_hwerrclear, 0ULL);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_errorclear,
                E_SPKT_ERRS_IGNORE);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_errormask,
                dd->ipath_errormask);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_intmask, -1LL);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, 0ULL);
}


/* this is separate to allow for better optimization of ipath_intr() */

static noinline void ipath_bad_intr(struct ipath_devdata *dd, u32 *unexpectp)
{
        /*
         * sometimes happen during driver init and unload, don't want
         * to process any interrupts at that point
         */

        /* this is just a bandaid, not a fix, if something goes badly
         * wrong */
        if (++*unexpectp > 100) {
                if (++*unexpectp > 105) {
                        /*
                         * ok, we must be taking somebody else's interrupts,
                         * due to a messed up mptable and/or PIRQ table, so
                         * unregister the interrupt.  We've seen this during
                         * linuxbios development work, and it may happen in
                         * the future again.
                         */
                        if (dd->pcidev && dd->ipath_irq) {
                                ipath_dev_err(dd, "Now %u unexpected "
                                              "interrupts, unregistering "
                                              "interrupt handler\n",
                                              *unexpectp);
                                ipath_dbg("free_irq of irq %d\n",
                                          dd->ipath_irq);
                                dd->ipath_f_free_irq(dd);
                        }
                }
                if (ipath_read_ireg(dd, dd->ipath_kregs->kr_intmask)) {
                        ipath_dev_err(dd, "%u unexpected interrupts, "
                                      "disabling interrupts completely\n",
                                      *unexpectp);
                        /*
                         * disable all interrupts, something is very wrong
                         */
                        ipath_write_kreg(dd, dd->ipath_kregs->kr_intmask,
                                         0ULL);
                }
        } else if (*unexpectp > 1)
                ipath_dbg("Interrupt when not ready, should not happen, "
                          "ignoring\n");
}

static noinline void ipath_bad_regread(struct ipath_devdata *dd)
{
        static int allbits;

        /* separate routine, for better optimization of ipath_intr() */

        /*
         * We print the message and disable interrupts, in hope of
         * having a better chance of debugging the problem.
         */
        ipath_dev_err(dd,
                      "Read of interrupt status failed (all bits set)\n");
        if (allbits++) {
                /* disable all interrupts, something is very wrong */
                ipath_write_kreg(dd, dd->ipath_kregs->kr_intmask, 0ULL);
                if (allbits == 2) {
                        ipath_dev_err(dd, "Still bad interrupt status, "
                                      "unregistering interrupt\n");
                        dd->ipath_f_free_irq(dd);
                } else if (allbits > 2) {
                        if ((allbits % 10000) == 0)
                                printk(".");
                } else
                        ipath_dev_err(dd, "Disabling interrupts, "
                                      "multiple errors\n");
        }
}

static void handle_layer_pioavail(struct ipath_devdata *dd)
{
        unsigned long flags;
        int ret;

        ret = ipath_ib_piobufavail(dd->verbs_dev);
        if (ret > 0)
                goto set;

        return;
set:
        spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
        dd->ipath_sendctrl |= INFINIPATH_S_PIOINTBUFAVAIL;
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                         dd->ipath_sendctrl);
        ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
        spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
}

/*
 * Handle receive interrupts for user ports; this means a user
 * process was waiting for a packet to arrive, and didn't want
 * to poll
 */
static void handle_urcv(struct ipath_devdata *dd, u64 istat)
{
        u64 portr;
        int i;
        int rcvdint = 0;

        /*
         * test_and_clear_bit(IPATH_PORT_WAITING_RCV) and
         * test_and_clear_bit(IPATH_PORT_WAITING_URG) below
         * would both like timely updates of the bits so that
         * we don't pass them by unnecessarily.  the rmb()
         * here ensures that we see them promptly -- the
         * corresponding wmb()'s are in ipath_poll_urgent()
         * and ipath_poll_next()...
         */
        rmb();
        portr = ((istat >> dd->ipath_i_rcvavail_shift) &
                 dd->ipath_i_rcvavail_mask) |
                ((istat >> dd->ipath_i_rcvurg_shift) &
                 dd->ipath_i_rcvurg_mask);
        for (i = 1; i < dd->ipath_cfgports; i++) {
                struct ipath_portdata *pd = dd->ipath_pd[i];

                if (portr & (1 << i) && pd && pd->port_cnt) {
                        if (test_and_clear_bit(IPATH_PORT_WAITING_RCV,
                                               &pd->port_flag)) {
                                clear_bit(i + dd->ipath_r_intravail_shift,
                                          &dd->ipath_rcvctrl);
                                wake_up_interruptible(&pd->port_wait);
                                rcvdint = 1;
                        } else if (test_and_clear_bit(IPATH_PORT_WAITING_URG,
                                                      &pd->port_flag)) {
                                pd->port_urgent++;
                                wake_up_interruptible(&pd->port_wait);
                        }
                }
        }
        if (rcvdint) {
                /* only want to take one interrupt, so turn off the rcv
                 * interrupt for all the ports that we set the rcv_waiting
                 * (but never for kernel port)
                 */
                ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
                                 dd->ipath_rcvctrl);
        }
}

irqreturn_t ipath_intr(int irq, void *data)
{
        struct ipath_devdata *dd = data;
        u64 istat, chk0rcv = 0;
        ipath_err_t estat = 0;
        irqreturn_t ret;
        static unsigned unexpected = 0;
        u64 kportrbits;

        ipath_stats.sps_ints++;

        if (dd->ipath_int_counter != (u32) -1)
                dd->ipath_int_counter++;

        if (!(dd->ipath_flags & IPATH_PRESENT)) {
                /*
                 * This return value is not great, but we do not want the
                 * interrupt core code to remove our interrupt handler
                 * because we don't appear to be handling an interrupt
                 * during a chip reset.
                 */
                return IRQ_HANDLED;
        }

        /*
         * this needs to be flags&initted, not statusp, so we keep
         * taking interrupts even after link goes down, etc.
         * Also, we *must* clear the interrupt at some point, or we won't
         * take it again, which can be real bad for errors, etc...
         */

        if (!(dd->ipath_flags & IPATH_INITTED)) {
                ipath_bad_intr(dd, &unexpected);
                ret = IRQ_NONE;
                goto bail;
        }

        istat = ipath_read_ireg(dd, dd->ipath_kregs->kr_intstatus);

        if (unlikely(!istat)) {
                ipath_stats.sps_nullintr++;
                ret = IRQ_NONE; /* not our interrupt, or already handled */
                goto bail;
        }
        if (unlikely(istat == -1)) {
                ipath_bad_regread(dd);
                /* don't know if it was our interrupt or not */
                ret = IRQ_NONE;
                goto bail;
        }

        if (unexpected)
                unexpected = 0;

        if (unlikely(istat & ~dd->ipath_i_bitsextant))
                ipath_dev_err(dd,
                              "interrupt with unknown interrupts %Lx set\n",
                              (unsigned long long)
                              istat & ~dd->ipath_i_bitsextant);
        else if (istat & ~INFINIPATH_I_ERROR) /* errors do own printing */
                ipath_cdbg(VERBOSE, "intr stat=0x%Lx\n",
                        (unsigned long long) istat);

        if (istat & INFINIPATH_I_ERROR) {
                ipath_stats.sps_errints++;
                estat = ipath_read_kreg64(dd,
                                          dd->ipath_kregs->kr_errorstatus);
                if (!estat)
                        dev_info(&dd->pcidev->dev, "error interrupt (%Lx), "
                                 "but no error bits set!\n",
                                 (unsigned long long) istat);
                else if (estat == -1LL)
                        /*
                         * should we try clearing all, or hope next read
                         * works?
                         */
                        ipath_dev_err(dd, "Read of error status failed "
                                      "(all bits set); ignoring\n");
                else
                        chk0rcv |= handle_errors(dd, estat);
        }

        if (istat & INFINIPATH_I_GPIO) {
                /*
                 * GPIO interrupts fall in two broad classes:
                 * GPIO_2 indicates (on some HT4xx boards) that a packet
                 *        has arrived for Port 0. Checking for this
                 *        is controlled by flag IPATH_GPIO_INTR.
                 * GPIO_3..5 on IBA6120 Rev2 and IBA6110 Rev4 chips indicate
                 *        errors that we need to count. Checking for this
                 *        is controlled by flag IPATH_GPIO_ERRINTRS.
                 */
                u32 gpiostatus;
                u32 to_clear = 0;

                gpiostatus = ipath_read_kreg32(
                        dd, dd->ipath_kregs->kr_gpio_status);
                /* First the error-counter case. */
                if ((gpiostatus & IPATH_GPIO_ERRINTR_MASK) &&
                    (dd->ipath_flags & IPATH_GPIO_ERRINTRS)) {
                        /* want to clear the bits we see asserted. */
                        to_clear |= (gpiostatus & IPATH_GPIO_ERRINTR_MASK);

                        /*
                         * Count appropriately, clear bits out of our copy,
                         * as they have been "handled".
                         */
                        if (gpiostatus & (1 << IPATH_GPIO_RXUVL_BIT)) {
                                ipath_dbg("FlowCtl on UnsupVL\n");
                                dd->ipath_rxfc_unsupvl_errs++;
                        }
                        if (gpiostatus & (1 << IPATH_GPIO_OVRUN_BIT)) {
                                ipath_dbg("Overrun Threshold exceeded\n");
                                dd->ipath_overrun_thresh_errs++;
                        }
                        if (gpiostatus & (1 << IPATH_GPIO_LLI_BIT)) {
                                ipath_dbg("Local Link Integrity error\n");
                                dd->ipath_lli_errs++;
                        }
                        gpiostatus &= ~IPATH_GPIO_ERRINTR_MASK;
                }
                /* Now the Port0 Receive case */
                if ((gpiostatus & (1 << IPATH_GPIO_PORT0_BIT)) &&
                    (dd->ipath_flags & IPATH_GPIO_INTR)) {
                        /*
                         * GPIO status bit 2 is set, and we expected it.
                         * clear it and indicate in p0bits.
                         * This probably only happens if a Port0 pkt
                         * arrives at _just_ the wrong time, and we
                         * handle that by seting chk0rcv;
                         */
                        to_clear |= (1 << IPATH_GPIO_PORT0_BIT);
                        gpiostatus &= ~(1 << IPATH_GPIO_PORT0_BIT);
                        chk0rcv = 1;
                }
                if (gpiostatus) {
                        /*
                         * Some unexpected bits remain. If they could have
                         * caused the interrupt, complain and clear.
                         * To avoid repetition of this condition, also clear
                         * the mask. It is almost certainly due to error.
                         */
                        const u32 mask = (u32) dd->ipath_gpio_mask;

                        if (mask & gpiostatus) {
                                ipath_dbg("Unexpected GPIO IRQ bits %x\n",
                                  gpiostatus & mask);
                                to_clear |= (gpiostatus & mask);
                                dd->ipath_gpio_mask &= ~(gpiostatus & mask);
                                ipath_write_kreg(dd,
                                        dd->ipath_kregs->kr_gpio_mask,
                                        dd->ipath_gpio_mask);
                        }
                }
                if (to_clear) {
                        ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
                                        (u64) to_clear);
                }
        }

        /*
         * Clear the interrupt bits we found set, unless they are receive
         * related, in which case we already cleared them above, and don't
         * want to clear them again, because we might lose an interrupt.
         * Clear it early, so we "know" know the chip will have seen this by
         * the time we process the queue, and will re-interrupt if necessary.
         * The processor itself won't take the interrupt again until we return.
         */
        ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, istat);

        /*
         * Handle kernel receive queues before checking for pio buffers
         * available since receives can overflow; piobuf waiters can afford
         * a few extra cycles, since they were waiting anyway, and user's
         * waiting for receive are at the bottom.
         */
        kportrbits = (1ULL << dd->ipath_i_rcvavail_shift) |
                (1ULL << dd->ipath_i_rcvurg_shift);
        if (chk0rcv || (istat & kportrbits)) {
                istat &= ~kportrbits;
                ipath_kreceive(dd->ipath_pd[0]);
        }

        if (istat & ((dd->ipath_i_rcvavail_mask << dd->ipath_i_rcvavail_shift) |
                     (dd->ipath_i_rcvurg_mask << dd->ipath_i_rcvurg_shift)))
                handle_urcv(dd, istat);

        if (istat & (INFINIPATH_I_SDMAINT | INFINIPATH_I_SDMADISABLED))
                handle_sdma_intr(dd, istat);

        if (istat & INFINIPATH_I_SPIOBUFAVAIL) {
                unsigned long flags;

                spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
                dd->ipath_sendctrl &= ~INFINIPATH_S_PIOINTBUFAVAIL;
                ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                                 dd->ipath_sendctrl);
                ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
                spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);

                /* always process; sdma verbs uses PIO for acks and VL15  */
                handle_layer_pioavail(dd);
        }

        ret = IRQ_HANDLED;

bail:
        return ret;
}