[PATCH] IB/ipath: fix lost interrupts on HT-400

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

/*
 * Copyright (c) 2006 QLogic, Inc. 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 "ipath_kernel.h"
#include "ips_common.h"
#include "ipath_layer.h"

/* 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)

/*
 * 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)
{
        unsigned long sbuf[4];
        u64 ignore_this_time = 0;
        u32 piobcnt;

        /* if possible that sendbuffererror could be valid */
        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);
                sbuf[3] = ipath_read_kreg64(
                        dd, dd->ipath_kregs->kr_sendbuffererror + 3);
        }

        if (sbuf[0] || sbuf[1] || (piobcnt > 128 && (sbuf[2] || sbuf[3]))) {
                int i;

                ipath_cdbg(PKT, "SendbufErrs %lx %lx ", sbuf[0], sbuf[1]);
                if (ipath_debug & __IPATH_PKTDBG && piobcnt > 128)
                        printk("%lx %lx ", sbuf[2], sbuf[3]);
                for (i = 0; i < piobcnt; i++) {
                        if (test_bit(i, sbuf)) {
                                u32 __iomem *piobuf;
                                if (i < dd->ipath_piobcnt2k)
                                        piobuf = (u32 __iomem *)
                                                (dd->ipath_pio2kbase +
                                                 i * dd->ipath_palign);
                                else
                                        piobuf = (u32 __iomem *)
                                                (dd->ipath_pio4kbase +
                                                 (i - dd->ipath_piobcnt2k) *
                                                 dd->ipath_4kalign);

                                ipath_cdbg(PKT,
                                           "PIObuf[%u] @%p pbc is %x; ",
                                           i, piobuf, readl(piobuf));

                                ipath_disarm_piobufs(dd, i, 1);
                        }
                }
                if (ipath_debug & __IPATH_PKTDBG)
                        printk("\n");
        }
        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;
}

/* return the strings for the most common link states */
static char *ib_linkstate(u32 linkstate)
{
        char *ret;

        switch (linkstate) {
        case IPATH_IBSTATE_INIT:
                ret = "Init";
                break;
        case IPATH_IBSTATE_ARM:
                ret = "Arm";
                break;
        case IPATH_IBSTATE_ACTIVE:
                ret = "Active";
                break;
        default:
                ret = "Down";
        }

        return ret;
}

static void handle_e_ibstatuschanged(struct ipath_devdata *dd,
                                     ipath_err_t errs, int noprint)
{
        u64 val;
        u32 ltstate, lstate;

        /*
         * even if diags are enabled, we want to notice LINKINIT, etc.
         * We just don't want to change the LED state, or
         * dd->ipath_kregs->kr_ibcctrl
         */
        val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_ibcstatus);
        lstate = val & IPATH_IBSTATE_MASK;

        /*
         * this is confusing enough when it happens that I want to always put it
         * on the console and in the logs.  If it was a requested state change,
         * we'll have already cleared the flags, so we won't print this warning
         */
        if ((lstate != IPATH_IBSTATE_ARM && lstate != IPATH_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(lstate));
                /*
                 * Flush all queued sends when link went to DOWN or INIT,
                 * to be sure that they don't block SMA and other MAD packets
                 */
                ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                                 INFINIPATH_S_ABORT);
                ipath_disarm_piobufs(dd, dd->ipath_lastport_piobuf,
                                                        (unsigned)(dd->ipath_piobcnt2k +
                                        dd->ipath_piobcnt4k) -
                                        dd->ipath_lastport_piobuf);
        }
        else if (lstate == IPATH_IBSTATE_INIT || lstate == IPATH_IBSTATE_ARM ||
            lstate == IPATH_IBSTATE_ACTIVE) {
                /*
                 * only print at SMA if there is a change, debug if not
                 * (sometimes we want to know that, usually not).
                 */
                if (lstate == ((unsigned) dd->ipath_lastibcstat
                               & IPATH_IBSTATE_MASK)) {
                        ipath_dbg("Status change intr but no change (%s)\n",
                                  ib_linkstate(lstate));
                }
                else
                        ipath_cdbg(SMA, "Unit %u link state %s, last "
                                   "was %s\n", dd->ipath_unit,
                                   ib_linkstate(lstate),
                                   ib_linkstate((unsigned)
                                                dd->ipath_lastibcstat
                                                & IPATH_IBSTATE_MASK));
        }
        else {
                lstate = dd->ipath_lastibcstat & IPATH_IBSTATE_MASK;
                if (lstate == IPATH_IBSTATE_INIT ||
                    lstate == IPATH_IBSTATE_ARM ||
                    lstate == IPATH_IBSTATE_ACTIVE)
                        ipath_cdbg(SMA, "Unit %u link state down"
                                   " (state 0x%x), from %s\n",
                                   dd->ipath_unit,
                                   (u32)val & IPATH_IBSTATE_MASK,
                                   ib_linkstate(lstate));
                else
                        ipath_cdbg(VERBOSE, "Unit %u link state changed "
                                   "to 0x%x from down (%x)\n",
                                   dd->ipath_unit, (u32) val, lstate);
        }
        ltstate = (val >> INFINIPATH_IBCS_LINKTRAININGSTATE_SHIFT) &
                INFINIPATH_IBCS_LINKTRAININGSTATE_MASK;
        lstate = (val >> INFINIPATH_IBCS_LINKSTATE_SHIFT) &
                INFINIPATH_IBCS_LINKSTATE_MASK;

        if (ltstate == INFINIPATH_IBCS_LT_STATE_POLLACTIVE ||
            ltstate == INFINIPATH_IBCS_LT_STATE_POLLQUIET) {
                u32 last_ltstate;

                /*
                 * Ignore cycling back and forth from Polling.Active
                 * to Polling.Quiet while waiting for the other end of
                 * the link to come up. We will cycle back and forth
                 * between them if no cable is plugged in,
                 * the other device is powered off or disabled, etc.
                 */
                last_ltstate = (dd->ipath_lastibcstat >>
                                INFINIPATH_IBCS_LINKTRAININGSTATE_SHIFT)
                        & INFINIPATH_IBCS_LINKTRAININGSTATE_MASK;
                if (last_ltstate == INFINIPATH_IBCS_LT_STATE_POLLACTIVE
                    || last_ltstate ==
                    INFINIPATH_IBCS_LT_STATE_POLLQUIET) {
                        if (dd->ipath_ibpollcnt > 40) {
                                dd->ipath_flags |= IPATH_NOCABLE;
                                *dd->ipath_statusp |=
                                        IPATH_STATUS_IB_NOCABLE;
                        } else
                                dd->ipath_ibpollcnt++;
                        goto skip_ibchange;
                }
        }
        dd->ipath_ibpollcnt = 0;        /* some state other than 2 or 3 */
        ipath_stats.sps_iblink++;
        if (ltstate != INFINIPATH_IBCS_LT_STATE_LINKUP) {
                dd->ipath_flags |= IPATH_LINKDOWN;
                dd->ipath_flags &= ~(IPATH_LINKUNK | IPATH_LINKINIT
                                     | IPATH_LINKACTIVE |
                                     IPATH_LINKARMED);
                *dd->ipath_statusp &= ~IPATH_STATUS_IB_READY;
                if (!noprint) {
                        if (((dd->ipath_lastibcstat >>
                              INFINIPATH_IBCS_LINKSTATE_SHIFT) &
                             INFINIPATH_IBCS_LINKSTATE_MASK)
                            == INFINIPATH_IBCS_L_STATE_ACTIVE)
                                /* if from up to down be more vocal */
                                ipath_cdbg(SMA,
                                           "Unit %u link now down (%s)\n",
                                           dd->ipath_unit,
                                           ipath_ibcstatus_str[ltstate]);
                        else
                                ipath_cdbg(VERBOSE, "Unit %u link is "
                                           "down (%s)\n", dd->ipath_unit,
                                           ipath_ibcstatus_str[ltstate]);
                }

                dd->ipath_f_setextled(dd, lstate, ltstate);
        } else if ((val & IPATH_IBSTATE_MASK) == IPATH_IBSTATE_ACTIVE) {
                dd->ipath_flags |= IPATH_LINKACTIVE;
                dd->ipath_flags &=
                        ~(IPATH_LINKUNK | IPATH_LINKINIT | IPATH_LINKDOWN |
                          IPATH_LINKARMED | IPATH_NOCABLE);
                *dd->ipath_statusp &= ~IPATH_STATUS_IB_NOCABLE;
                *dd->ipath_statusp |=
                        IPATH_STATUS_IB_READY | IPATH_STATUS_IB_CONF;
                dd->ipath_f_setextled(dd, lstate, ltstate);

                __ipath_layer_intr(dd, IPATH_LAYER_INT_IF_UP);
        } else if ((val & IPATH_IBSTATE_MASK) == IPATH_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_LINKACTIVE | IPATH_LINKARMED
                          | IPATH_NOCABLE);
                *dd->ipath_statusp &= ~(IPATH_STATUS_IB_NOCABLE
                                        | IPATH_STATUS_IB_READY);
                dd->ipath_f_setextled(dd, lstate, ltstate);
        } else if ((val & IPATH_IBSTATE_MASK) == IPATH_IBSTATE_ARM) {
                dd->ipath_flags |= IPATH_LINKARMED;
                dd->ipath_flags &=
                        ~(IPATH_LINKUNK | IPATH_LINKDOWN | IPATH_LINKINIT |
                          IPATH_LINKACTIVE | IPATH_NOCABLE);
                *dd->ipath_statusp &= ~(IPATH_STATUS_IB_NOCABLE
                                        | IPATH_STATUS_IB_READY);
                dd->ipath_f_setextled(dd, lstate, ltstate);
        } else {
                if (!noprint)
                        ipath_dbg("IBstatuschange unit %u: %s (%x)\n",
                                  dd->ipath_unit,
                                  ipath_ibcstatus_str[ltstate], ltstate);
        }
skip_ibchange:
        dd->ipath_lastibcstat = val;
}

static void handle_supp_msgs(struct ipath_devdata *dd,
                             unsigned supp_msgs, char msg[512])
{
        /*
         * 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) {
                ipath_decode_err(msg, sizeof msg, dd->ipath_lasterror &
                                 ~INFINIPATH_E_IBSTATUSCHANGED);
                if (dd->ipath_lasterror &
                    ~(INFINIPATH_E_RRCVEGRFULL | INFINIPATH_E_RRCVHDRFULL))
                        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.
                         */
                        ipath_dbg("Suppressed %u messages for %s\n",
                                  supp_msgs, msg);
                }
        }
}

static unsigned handle_frequent_errors(struct ipath_devdata *dd,
                                       ipath_err_t errs, char msg[512],
                                       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);
                        supp_msgs = 0;
                        nmsgs = 0;
                }
        }
        else if (!nmsgs++ || time_after(nc, nextmsg_time))
                nextmsg_time = nc + HZ / 2;

        return supp_msgs;
}

static int handle_errors(struct ipath_devdata *dd, ipath_err_t errs)
{
        char msg[512];
        u64 ignore_this_time = 0;
        int i;
        int chkerrpkts = 0, noprint = 0;
        unsigned supp_msgs;

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

        /*
         * don't report errors that are masked (includes those always
         * ignored)
         */
        errs &= ~dd->ipath_maskederrs;

        /* 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);
        }

        if (!noprint && (errs & ~infinipath_e_bitsextant))
                ipath_dev_err(dd, "error interrupt with unknown errors "
                              "%llx set\n", (unsigned long long)
                              (errs & ~infinipath_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) {
                /*
                 * 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;
                ipath_write_kreg(dd, dd->ipath_kregs->kr_errormask,
                                 ~dd->ipath_maskederrs);
                ipath_decode_err(msg, sizeof msg,
                                 (dd->ipath_maskederrs & ~dd->
                                  ipath_ignorederrs));

                if ((dd->ipath_maskederrs & ~dd->ipath_ignorederrs) &
                    ~(INFINIPATH_E_RRCVEGRFULL | INFINIPATH_E_RRCVHDRFULL))
                        ipath_dev_err(dd, "Disabling error(s) %llx because "
                                      "occurring too frequently (%s)\n",
                                      (unsigned long long)
                                      (dd->ipath_maskederrs &
                                       ~dd->ipath_ignorederrs), 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.
                         */
                        ipath_dbg("Disabling frequent queue full 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)
                return 0;

        if (!noprint)
                /*
                 * the ones we mask off are handled specially below or above
                 */
                ipath_decode_err(msg, sizeof msg,
                                 errs & ~(INFINIPATH_E_IBSTATUSCHANGED |
                                          INFINIPATH_E_RRCVEGRFULL |
                                          INFINIPATH_E_RRCVHDRFULL |
                                          INFINIPATH_E_HARDWARE));
        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;
        }

        /*
         * 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) {
                int any;
                u32 hd, tl;
                ipath_stats.sps_hdrqfull++;
                for (any = i = 0; i < dd->ipath_cfgports; i++) {
                        struct ipath_portdata *pd = dd->ipath_pd[i];
                        if (i == 0) {
                                hd = dd->ipath_port0head;
                                tl = (u32) le64_to_cpu(
                                        *dd->ipath_hdrqtailptr);
                        } else if (pd && pd->port_cnt &&
                                   pd->port_rcvhdrtail_kvaddr) {
                                /*
                                 * don't report same point multiple times,
                                 * except kernel
                                 */
                                tl = (u32) * pd->port_rcvhdrtail_kvaddr;
                                if (tl == dd->ipath_lastrcvhdrqtails[i])
                                        continue;
                                hd = ipath_read_ureg32(dd, ur_rcvhdrhead,
                                                       i);
                        } else
                                continue;
                        if (hd == (tl + 1) ||
                            (!hd && tl == dd->ipath_hdrqlast)) {
                                if (i == 0)
                                        chkerrpkts = 1;
                                dd->ipath_lastrcvhdrqtails[i] = tl;
                                pd->port_hdrqfull++;
                        }
                }
        }
        if (errs & INFINIPATH_E_RRCVEGRFULL) {
                /*
                 * 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 (dd->ipath_port0head !=
                    (u32) le64_to_cpu(*dd->ipath_hdrqtailptr))
                        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;
                if (!noprint) {
                        u64 st = ipath_read_kreg64(
                                dd, dd->ipath_kregs->kr_ibcstatus);

                        ipath_dbg("Lost link, link now down (%s)\n",
                                  ipath_ibcstatus_str[st & 0xf]);
                }
        }
        if (errs & INFINIPATH_E_IBSTATUSCHANGED)
                handle_e_ibstatuschanged(dd, errs, noprint);

        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)
                ipath_dev_err(dd, "%s error\n", msg);
        if (dd->ipath_sma_state_wanted & dd->ipath_flags) {
                ipath_cdbg(VERBOSE, "sma wanted state %x, iflags now %x, "
                           "waking\n", dd->ipath_sma_state_wanted,
                           dd->ipath_flags);
                wake_up_interruptible(&ipath_sma_state_wait);
        }

        return chkerrpkts;
}

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

static 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->pcidev->irq) {
                                ipath_dev_err(dd, "Now %u unexpected "
                                              "interrupts, unregistering "
                                              "interrupt handler\n",
                                              *unexpectp);
                                ipath_dbg("free_irq of irq %x\n",
                                          dd->pcidev->irq);
                                free_irq(dd->pcidev->irq, dd);
                        }
                }
                if (ipath_read_kreg32(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 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");
                        free_irq(dd->pcidev->irq, dd);
                } else if (allbits > 2) {
                        if ((allbits % 10000) == 0)
                                printk(".");
                } else
                        ipath_dev_err(dd, "Disabling interrupts, "
                                      "multiple errors\n");
        }
}

static void handle_port_pioavail(struct ipath_devdata *dd)
{
        u32 i;
        /*
         * start from port 1, since for now port 0  is never using
         * wait_event for PIO
         */
        for (i = 1; dd->ipath_portpiowait && i < dd->ipath_cfgports; i++) {
                struct ipath_portdata *pd = dd->ipath_pd[i];

                if (pd && pd->port_cnt &&
                    dd->ipath_portpiowait & (1U << i)) {
                        clear_bit(i, &dd->ipath_portpiowait);
                        if (test_bit(IPATH_PORT_WAITING_PIO,
                                     &pd->port_flag)) {
                                clear_bit(IPATH_PORT_WAITING_PIO,
                                          &pd->port_flag);
                                wake_up_interruptible(&pd->port_wait);
                        }
                }
        }
}

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

        ret = __ipath_layer_intr(dd, IPATH_LAYER_INT_SEND_CONTINUE);
        if (ret > 0)
                goto set;

        ret = __ipath_verbs_piobufavail(dd);
        if (ret > 0)
                goto set;

        return;
set:
        set_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                         dd->ipath_sendctrl);
}

/*
 * 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, u32 istat)
{
        u64 portr;
        int i;
        int rcvdint = 0;

        portr = ((istat >> INFINIPATH_I_RCVAVAIL_SHIFT) &
                 infinipath_i_rcvavail_mask)
                | ((istat >> INFINIPATH_I_RCVURG_SHIFT) &
                   infinipath_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 &&
                        test_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag)) {
                        int rcbit;
                        clear_bit(IPATH_PORT_WAITING_RCV,
                                  &pd->port_flag);
                        rcbit = i + INFINIPATH_R_INTRAVAIL_SHIFT;
                        clear_bit(1UL << rcbit, &dd->ipath_rcvctrl);
                        wake_up_interruptible(&pd->port_wait);
                        rcvdint = 1;
                }
        }
        if (rcvdint) {
                /* only want to take one interrupt, so turn off the rcv
                 * interrupt for all the ports that we did the wakeup on
                 * (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 pt_regs *regs)
{
        struct ipath_devdata *dd = data;
        u32 istat, chk0rcv = 0;
        ipath_err_t estat = 0;
        irqreturn_t ret;
        u32 oldhead, curtail;
        static unsigned unexpected = 0;
        static const u32 port0rbits = (1U<<INFINIPATH_I_RCVAVAIL_SHIFT) |
                 (1U<<INFINIPATH_I_RCVURG_SHIFT);

        ipath_stats.sps_ints++;

        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;
        }

        /*
         * We try to avoid reading the interrupt status register, since
         * that's a PIO read, and stalls the processor for up to about
         * ~0.25 usec. The idea is that if we processed a port0 packet,
         * we blindly clear the  port 0 receive interrupt bits, and nothing
         * else, then return.  If other interrupts are pending, the chip
         * will re-interrupt us as soon as we write the intclear register.
         * We then won't process any more kernel packets (if not the 2nd
         * time, then the 3rd or 4th) and we'll then handle the other
         * interrupts.   We clear the interrupts first so that we don't
         * lose intr for later packets that arrive while we are processing.
         */
        oldhead = dd->ipath_port0head;
        curtail = (u32)le64_to_cpu(*dd->ipath_hdrqtailptr);
        if (oldhead != curtail) {
                if (dd->ipath_flags & IPATH_GPIO_INTR) {
                        ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
                                         (u64) (1 << 2));
                        istat = port0rbits | INFINIPATH_I_GPIO;
                }
                else
                        istat = port0rbits;
                ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, istat);
                ipath_kreceive(dd);
                if (oldhead != dd->ipath_port0head) {
                        ipath_stats.sps_fastrcvint++;
                        goto done;
                }
                istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
        }

        istat = ipath_read_kreg32(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 & ~infinipath_i_bitsextant))
                ipath_dev_err(dd,
                              "interrupt with unknown interrupts %x set\n",
                              istat & (u32) ~ infinipath_i_bitsextant);
        else
                ipath_cdbg(VERBOSE, "intr stat=0x%x\n", istat);

        if (unlikely(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 (%x), "
                                 "but no error bits set!\n", 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
                        if (handle_errors(dd, estat))
                                /* force calling ipath_kreceive() */
                                chk0rcv = 1;
        }

        if (istat & INFINIPATH_I_GPIO) {
                /*
                 * Packets are available in the port 0 rcv queue.
                 * Eventually this needs to be generalized to check
                 * IPATH_GPIO_INTR, and the specific GPIO bit, if
                 * GPIO interrupts are used for anything else.
                 */
                if (unlikely(!(dd->ipath_flags & IPATH_GPIO_INTR))) {
                        u32 gpiostatus;
                        gpiostatus = ipath_read_kreg32(
                                dd, dd->ipath_kregs->kr_gpio_status);
                        ipath_dbg("Unexpected GPIO interrupt bits %x\n",
                                  gpiostatus);
                        ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
                                         gpiostatus);
                }
                else {
                        /* Clear GPIO status bit 2 */
                        ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
                                        (u64) (1 << 2));
                        chk0rcv = 1;
                }
        }
        chk0rcv |= istat & port0rbits;

        /*
         * 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 port0 receive  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.
         */
        if (chk0rcv) {
                ipath_kreceive(dd);
                istat &= ~port0rbits;
        }

        if (istat & ((infinipath_i_rcvavail_mask <<
                      INFINIPATH_I_RCVAVAIL_SHIFT)
                     | (infinipath_i_rcvurg_mask <<
                        INFINIPATH_I_RCVURG_SHIFT)))
                handle_urcv(dd, istat);

        if (istat & INFINIPATH_I_SPIOBUFAVAIL) {
                clear_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
                ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                                 dd->ipath_sendctrl);

                if (dd->ipath_portpiowait)
                        handle_port_pioavail(dd);

                handle_layer_pioavail(dd);
        }

done:
        ret = IRQ_HANDLED;

bail:
        return ret;
}