staging/rdma/hfi1: don't cache "prescan head"

[mirror_ubuntu-artful-kernel.git] / drivers / staging / rdma / hfi1 / driver.c

/*
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * 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.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/prefetch.h>

#include "hfi.h"
#include "trace.h"
#include "qp.h"
#include "sdma.h"

#undef pr_fmt
#define pr_fmt(fmt) DRIVER_NAME ": " fmt

/*
 * The size has to be longer than this string, so we can append
 * board/chip information to it in the initialization code.
 */
const char ib_hfi1_version[] = HFI1_DRIVER_VERSION "\n";

DEFINE_SPINLOCK(hfi1_devs_lock);
LIST_HEAD(hfi1_dev_list);
DEFINE_MUTEX(hfi1_mutex);       /* general driver use */

unsigned int hfi1_max_mtu = HFI1_DEFAULT_MAX_MTU;
module_param_named(max_mtu, hfi1_max_mtu, uint, S_IRUGO);
MODULE_PARM_DESC(max_mtu, "Set max MTU bytes, default is 8192");

unsigned int hfi1_cu = 1;
module_param_named(cu, hfi1_cu, uint, S_IRUGO);
MODULE_PARM_DESC(cu, "Credit return units");

unsigned long hfi1_cap_mask = HFI1_CAP_MASK_DEFAULT;
static int hfi1_caps_set(const char *, const struct kernel_param *);
static int hfi1_caps_get(char *, const struct kernel_param *);
static const struct kernel_param_ops cap_ops = {
        .set = hfi1_caps_set,
        .get = hfi1_caps_get
};
module_param_cb(cap_mask, &cap_ops, &hfi1_cap_mask, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(cap_mask, "Bit mask of enabled/disabled HW features");

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("Intel Omni-Path Architecture driver");
MODULE_VERSION(HFI1_DRIVER_VERSION);

/*
 * MAX_PKT_RCV is the max # if packets processed per receive interrupt.
 */
#define MAX_PKT_RECV 64
#define EGR_HEAD_UPDATE_THRESHOLD 16

struct hfi1_ib_stats hfi1_stats;

static int hfi1_caps_set(const char *val, const struct kernel_param *kp)
{
        int ret = 0;
        unsigned long *cap_mask_ptr = (unsigned long *)kp->arg,
                cap_mask = *cap_mask_ptr, value, diff,
                write_mask = ((HFI1_CAP_WRITABLE_MASK << HFI1_CAP_USER_SHIFT) |
                              HFI1_CAP_WRITABLE_MASK);

        ret = kstrtoul(val, 0, &value);
        if (ret) {
                pr_warn("Invalid module parameter value for 'cap_mask'\n");
                goto done;
        }
        /* Get the changed bits (except the locked bit) */
        diff = value ^ (cap_mask & ~HFI1_CAP_LOCKED_SMASK);

        /* Remove any bits that are not allowed to change after driver load */
        if (HFI1_CAP_LOCKED() && (diff & ~write_mask)) {
                pr_warn("Ignoring non-writable capability bits %#lx\n",
                        diff & ~write_mask);
                diff &= write_mask;
        }

        /* Mask off any reserved bits */
        diff &= ~HFI1_CAP_RESERVED_MASK;
        /* Clear any previously set and changing bits */
        cap_mask &= ~diff;
        /* Update the bits with the new capability */
        cap_mask |= (value & diff);
        /* Check for any kernel/user restrictions */
        diff = (cap_mask & (HFI1_CAP_MUST_HAVE_KERN << HFI1_CAP_USER_SHIFT)) ^
                ((cap_mask & HFI1_CAP_MUST_HAVE_KERN) << HFI1_CAP_USER_SHIFT);
        cap_mask &= ~diff;
        /* Set the bitmask to the final set */
        *cap_mask_ptr = cap_mask;
done:
        return ret;
}

static int hfi1_caps_get(char *buffer, const struct kernel_param *kp)
{
        unsigned long cap_mask = *(unsigned long *)kp->arg;

        cap_mask &= ~HFI1_CAP_LOCKED_SMASK;
        cap_mask |= ((cap_mask & HFI1_CAP_K2U) << HFI1_CAP_USER_SHIFT);

        return scnprintf(buffer, PAGE_SIZE, "0x%lx", cap_mask);
}

const char *get_unit_name(int unit)
{
        static char iname[16];

        snprintf(iname, sizeof(iname), DRIVER_NAME"_%u", unit);
        return iname;
}

/*
 * Return count of units with at least one port ACTIVE.
 */
int hfi1_count_active_units(void)
{
        struct hfi1_devdata *dd;
        struct hfi1_pportdata *ppd;
        unsigned long flags;
        int pidx, nunits_active = 0;

        spin_lock_irqsave(&hfi1_devs_lock, flags);
        list_for_each_entry(dd, &hfi1_dev_list, list) {
                if (!(dd->flags & HFI1_PRESENT) || !dd->kregbase)
                        continue;
                for (pidx = 0; pidx < dd->num_pports; ++pidx) {
                        ppd = dd->pport + pidx;
                        if (ppd->lid && ppd->linkup) {
                                nunits_active++;
                                break;
                        }
                }
        }
        spin_unlock_irqrestore(&hfi1_devs_lock, flags);
        return nunits_active;
}

/*
 * Return count of all units, optionally return in arguments
 * the number of usable (present) units, and the number of
 * ports that are up.
 */
int hfi1_count_units(int *npresentp, int *nupp)
{
        int nunits = 0, npresent = 0, nup = 0;
        struct hfi1_devdata *dd;
        unsigned long flags;
        int pidx;
        struct hfi1_pportdata *ppd;

        spin_lock_irqsave(&hfi1_devs_lock, flags);

        list_for_each_entry(dd, &hfi1_dev_list, list) {
                nunits++;
                if ((dd->flags & HFI1_PRESENT) && dd->kregbase)
                        npresent++;
                for (pidx = 0; pidx < dd->num_pports; ++pidx) {
                        ppd = dd->pport + pidx;
                        if (ppd->lid && ppd->linkup)
                                nup++;
                }
        }

        spin_unlock_irqrestore(&hfi1_devs_lock, flags);

        if (npresentp)
                *npresentp = npresent;
        if (nupp)
                *nupp = nup;

        return nunits;
}

/*
 * Get address of eager buffer from it's index (allocated in chunks, not
 * contiguous).
 */
static inline void *get_egrbuf(const struct hfi1_ctxtdata *rcd, u64 rhf,
                               u8 *update)
{
        u32 idx = rhf_egr_index(rhf), offset = rhf_egr_buf_offset(rhf);

        *update |= !(idx & (rcd->egrbufs.threshold - 1)) && !offset;
        return (void *)(((u64)(rcd->egrbufs.rcvtids[idx].addr)) +
                        (offset * RCV_BUF_BLOCK_SIZE));
}

/*
 * Validate and encode the a given RcvArray Buffer size.
 * The function will check whether the given size falls within
 * allowed size ranges for the respective type and, optionally,
 * return the proper encoding.
 */
inline int hfi1_rcvbuf_validate(u32 size, u8 type, u16 *encoded)
{
        if (unlikely(!IS_ALIGNED(size, PAGE_SIZE)))
                return 0;
        if (unlikely(size < MIN_EAGER_BUFFER))
                return 0;
        if (size >
            (type == PT_EAGER ? MAX_EAGER_BUFFER : MAX_EXPECTED_BUFFER))
                return 0;
        if (encoded)
                *encoded = ilog2(size / PAGE_SIZE) + 1;
        return 1;
}

static void rcv_hdrerr(struct hfi1_ctxtdata *rcd, struct hfi1_pportdata *ppd,
                       struct hfi1_packet *packet)
{
        struct hfi1_message_header *rhdr = packet->hdr;
        u32 rte = rhf_rcv_type_err(packet->rhf);
        int lnh = be16_to_cpu(rhdr->lrh[0]) & 3;
        struct hfi1_ibport *ibp = &ppd->ibport_data;

        if (packet->rhf & (RHF_VCRC_ERR | RHF_ICRC_ERR))
                return;

        if (packet->rhf & RHF_TID_ERR) {
                /* For TIDERR and RC QPs preemptively schedule a NAK */
                struct hfi1_ib_header *hdr = (struct hfi1_ib_header *)rhdr;
                struct hfi1_other_headers *ohdr = NULL;
                u32 tlen = rhf_pkt_len(packet->rhf); /* in bytes */
                u16 lid  = be16_to_cpu(hdr->lrh[1]);
                u32 qp_num;
                u32 rcv_flags = 0;

                /* Sanity check packet */
                if (tlen < 24)
                        goto drop;

                /* Check for GRH */
                if (lnh == HFI1_LRH_BTH)
                        ohdr = &hdr->u.oth;
                else if (lnh == HFI1_LRH_GRH) {
                        u32 vtf;

                        ohdr = &hdr->u.l.oth;
                        if (hdr->u.l.grh.next_hdr != IB_GRH_NEXT_HDR)
                                goto drop;
                        vtf = be32_to_cpu(hdr->u.l.grh.version_tclass_flow);
                        if ((vtf >> IB_GRH_VERSION_SHIFT) != IB_GRH_VERSION)
                                goto drop;
                        rcv_flags |= HFI1_HAS_GRH;
                } else
                        goto drop;

                /* Get the destination QP number. */
                qp_num = be32_to_cpu(ohdr->bth[1]) & HFI1_QPN_MASK;
                if (lid < HFI1_MULTICAST_LID_BASE) {
                        struct hfi1_qp *qp;
                        unsigned long flags;

                        rcu_read_lock();
                        qp = hfi1_lookup_qpn(ibp, qp_num);
                        if (!qp) {
                                rcu_read_unlock();
                                goto drop;
                        }

                        /*
                         * Handle only RC QPs - for other QP types drop error
                         * packet.
                         */
                        spin_lock_irqsave(&qp->r_lock, flags);

                        /* Check for valid receive state. */
                        if (!(ib_hfi1_state_ops[qp->state] &
                              HFI1_PROCESS_RECV_OK)) {
                                ibp->n_pkt_drops++;
                        }

                        switch (qp->ibqp.qp_type) {
                        case IB_QPT_RC:
                                hfi1_rc_hdrerr(
                                        rcd,
                                        hdr,
                                        rcv_flags,
                                        qp);
                                break;
                        default:
                                /* For now don't handle any other QP types */
                                break;
                        }

                        spin_unlock_irqrestore(&qp->r_lock, flags);
                        rcu_read_unlock();
                } /* Unicast QP */
        } /* Valid packet with TIDErr */

        /* handle "RcvTypeErr" flags */
        switch (rte) {
        case RHF_RTE_ERROR_OP_CODE_ERR:
        {
                u32 opcode;
                void *ebuf = NULL;
                __be32 *bth = NULL;

                if (rhf_use_egr_bfr(packet->rhf))
                        ebuf = packet->ebuf;

                if (ebuf == NULL)
                        goto drop; /* this should never happen */

                if (lnh == HFI1_LRH_BTH)
                        bth = (__be32 *)ebuf;
                else if (lnh == HFI1_LRH_GRH)
                        bth = (__be32 *)((char *)ebuf + sizeof(struct ib_grh));
                else
                        goto drop;

                opcode = be32_to_cpu(bth[0]) >> 24;
                opcode &= 0xff;

                if (opcode == IB_OPCODE_CNP) {
                        /*
                         * Only in pre-B0 h/w is the CNP_OPCODE handled
                         * via this code path (errata 291394).
                         */
                        struct hfi1_qp *qp = NULL;
                        u32 lqpn, rqpn;
                        u16 rlid;
                        u8 svc_type, sl, sc5;

                        sc5  = (be16_to_cpu(rhdr->lrh[0]) >> 12) & 0xf;
                        if (rhf_dc_info(packet->rhf))
                                sc5 |= 0x10;
                        sl = ibp->sc_to_sl[sc5];

                        lqpn = be32_to_cpu(bth[1]) & HFI1_QPN_MASK;
                        rcu_read_lock();
                        qp = hfi1_lookup_qpn(ibp, lqpn);
                        if (qp == NULL) {
                                rcu_read_unlock();
                                goto drop;
                        }

                        switch (qp->ibqp.qp_type) {
                        case IB_QPT_UD:
                                rlid = 0;
                                rqpn = 0;
                                svc_type = IB_CC_SVCTYPE_UD;
                                break;
                        case IB_QPT_UC:
                                rlid = be16_to_cpu(rhdr->lrh[3]);
                                rqpn = qp->remote_qpn;
                                svc_type = IB_CC_SVCTYPE_UC;
                                break;
                        default:
                                goto drop;
                        }

                        process_becn(ppd, sl, rlid, lqpn, rqpn, svc_type);
                        rcu_read_unlock();
                }

                packet->rhf &= ~RHF_RCV_TYPE_ERR_SMASK;
                break;
        }
        default:
                break;
        }

drop:
        return;
}

static inline void init_packet(struct hfi1_ctxtdata *rcd,
                              struct hfi1_packet *packet)
{

        packet->rsize = rcd->rcvhdrqentsize; /* words */
        packet->maxcnt = rcd->rcvhdrq_cnt * packet->rsize; /* words */
        packet->rcd = rcd;
        packet->updegr = 0;
        packet->etail = -1;
        packet->rhf_addr = get_rhf_addr(rcd);
        packet->rhf = rhf_to_cpu(packet->rhf_addr);
        packet->rhqoff = rcd->head;
        packet->numpkt = 0;
        packet->rcv_flags = 0;
}

#ifndef CONFIG_PRESCAN_RXQ
static void prescan_rxq(struct hfi1_packet *packet) {}
#else /* CONFIG_PRESCAN_RXQ */
static int prescan_receive_queue;

static void process_ecn(struct hfi1_qp *qp, struct hfi1_ib_header *hdr,
                        struct hfi1_other_headers *ohdr,
                        u64 rhf, struct ib_grh *grh)
{
        struct hfi1_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
        u32 bth1;
        u8 sc5, svc_type;
        int is_fecn, is_becn;

        switch (qp->ibqp.qp_type) {
        case IB_QPT_UD:
                svc_type = IB_CC_SVCTYPE_UD;
                break;
        case IB_QPT_UC: /* LATER */
        case IB_QPT_RC: /* LATER */
        default:
                return;
        }

        is_fecn = (be32_to_cpu(ohdr->bth[1]) >> HFI1_FECN_SHIFT) &
                        HFI1_FECN_MASK;
        is_becn = (be32_to_cpu(ohdr->bth[1]) >> HFI1_BECN_SHIFT) &
                        HFI1_BECN_MASK;

        sc5 = (be16_to_cpu(hdr->lrh[0]) >> 12) & 0xf;
        if (rhf_dc_info(rhf))
                sc5 |= 0x10;

        if (is_fecn) {
                u32 src_qpn = be32_to_cpu(ohdr->u.ud.deth[1]) & HFI1_QPN_MASK;
                u16 pkey = (u16)be32_to_cpu(ohdr->bth[0]);
                u16 dlid = be16_to_cpu(hdr->lrh[1]);
                u16 slid = be16_to_cpu(hdr->lrh[3]);

                return_cnp(ibp, qp, src_qpn, pkey, dlid, slid, sc5, grh);
        }

        if (is_becn) {
                struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
                u32 lqpn =  be32_to_cpu(ohdr->bth[1]) & HFI1_QPN_MASK;
                u8 sl = ibp->sc_to_sl[sc5];

                process_becn(ppd, sl, 0, lqpn, 0, svc_type);
        }

        /* turn off BECN, or FECN */
        bth1 = be32_to_cpu(ohdr->bth[1]);
        bth1 &= ~(HFI1_FECN_MASK << HFI1_FECN_SHIFT);
        bth1 &= ~(HFI1_BECN_MASK << HFI1_BECN_SHIFT);
        ohdr->bth[1] = cpu_to_be32(bth1);
}

struct ps_mdata {
        struct hfi1_ctxtdata *rcd;
        u32 rsize;
        u32 maxcnt;
        u32 ps_head;
        u32 ps_tail;
        u32 ps_seq;
};

static inline void init_ps_mdata(struct ps_mdata *mdata,
                                 struct hfi1_packet *packet)
{
        struct hfi1_ctxtdata *rcd = packet->rcd;

        mdata->rcd = rcd;
        mdata->rsize = packet->rsize;
        mdata->maxcnt = packet->maxcnt;

        mdata->ps_head = packet->rhqoff;

        if (HFI1_CAP_IS_KSET(DMA_RTAIL)) {
                mdata->ps_tail = get_rcvhdrtail(rcd);
                mdata->ps_seq = 0; /* not used with DMA_RTAIL */
        } else {
                mdata->ps_tail = 0; /* used only with DMA_RTAIL*/
                mdata->ps_seq = rcd->seq_cnt;
        }
}

static inline int ps_done(struct ps_mdata *mdata, u64 rhf)
{
        if (HFI1_CAP_IS_KSET(DMA_RTAIL))
                return mdata->ps_head == mdata->ps_tail;
        return mdata->ps_seq != rhf_rcv_seq(rhf);
}

static inline void update_ps_mdata(struct ps_mdata *mdata)
{
        mdata->ps_head += mdata->rsize;
        if (mdata->ps_head >= mdata->maxcnt)
                mdata->ps_head = 0;
        if (!HFI1_CAP_IS_KSET(DMA_RTAIL)) {
                if (++mdata->ps_seq > 13)
                        mdata->ps_seq = 1;
        }
}

/*
 * prescan_rxq - search through the receive queue looking for packets
 * containing Excplicit Congestion Notifications (FECNs, or BECNs).
 * When an ECN is found, process the Congestion Notification, and toggle
 * it off.
 */
static void prescan_rxq(struct hfi1_packet *packet)
{
        struct hfi1_ctxtdata *rcd = packet->rcd;
        struct ps_mdata mdata;

        if (!prescan_receive_queue)
                return;

        init_ps_mdata(&mdata, packet);

        while (1) {
                struct hfi1_devdata *dd = rcd->dd;
                struct hfi1_ibport *ibp = &rcd->ppd->ibport_data;
                __le32 *rhf_addr = (__le32 *) rcd->rcvhdrq + mdata.ps_head +
                                         dd->rhf_offset;
                struct hfi1_qp *qp;
                struct hfi1_ib_header *hdr;
                struct hfi1_other_headers *ohdr;
                struct ib_grh *grh = NULL;
                u64 rhf = rhf_to_cpu(rhf_addr);
                u32 etype = rhf_rcv_type(rhf), qpn;
                int is_ecn = 0;
                u8 lnh;

                if (ps_done(&mdata, rhf))
                        break;

                if (etype != RHF_RCV_TYPE_IB)
                        goto next;

                hdr = (struct hfi1_ib_header *)
                        hfi1_get_msgheader(dd, rhf_addr);
                lnh = be16_to_cpu(hdr->lrh[0]) & 3;

                if (lnh == HFI1_LRH_BTH)
                        ohdr = &hdr->u.oth;
                else if (lnh == HFI1_LRH_GRH) {
                        ohdr = &hdr->u.l.oth;
                        grh = &hdr->u.l.grh;
                } else
                        goto next; /* just in case */

                is_ecn |= be32_to_cpu(ohdr->bth[1]) &
                        (HFI1_FECN_MASK << HFI1_FECN_SHIFT);
                is_ecn |= be32_to_cpu(ohdr->bth[1]) &
                        (HFI1_BECN_MASK << HFI1_BECN_SHIFT);

                if (!is_ecn)
                        goto next;

                qpn = be32_to_cpu(ohdr->bth[1]) & HFI1_QPN_MASK;
                rcu_read_lock();
                qp = hfi1_lookup_qpn(ibp, qpn);

                if (qp == NULL) {
                        rcu_read_unlock();
                        goto next;
                }

                process_ecn(qp, hdr, ohdr, rhf, grh);
                rcu_read_unlock();
next:
                update_ps_mdata(&mdata);
        }
}
#endif /* CONFIG_PRESCAN_RXQ */

static inline int process_rcv_packet(struct hfi1_packet *packet, int thread)
{
        int ret = RCV_PKT_OK;

        packet->hdr = hfi1_get_msgheader(packet->rcd->dd,
                                         packet->rhf_addr);
        packet->hlen = (u8 *)packet->rhf_addr - (u8 *)packet->hdr;
        packet->etype = rhf_rcv_type(packet->rhf);
        /* total length */
        packet->tlen = rhf_pkt_len(packet->rhf); /* in bytes */
        /* retrieve eager buffer details */
        packet->ebuf = NULL;
        if (rhf_use_egr_bfr(packet->rhf)) {
                packet->etail = rhf_egr_index(packet->rhf);
                packet->ebuf = get_egrbuf(packet->rcd, packet->rhf,
                                 &packet->updegr);
                /*
                 * Prefetch the contents of the eager buffer.  It is
                 * OK to send a negative length to prefetch_range().
                 * The +2 is the size of the RHF.
                 */
                prefetch_range(packet->ebuf,
                        packet->tlen - ((packet->rcd->rcvhdrqentsize -
                                  (rhf_hdrq_offset(packet->rhf)+2)) * 4));
        }

        /*
         * Call a type specific handler for the packet. We
         * should be able to trust that etype won't be beyond
         * the range of valid indexes. If so something is really
         * wrong and we can probably just let things come
         * crashing down. There is no need to eat another
         * comparison in this performance critical code.
         */
        packet->rcd->dd->rhf_rcv_function_map[packet->etype](packet);
        packet->numpkt++;

        /* Set up for the next packet */
        packet->rhqoff += packet->rsize;
        if (packet->rhqoff >= packet->maxcnt)
                packet->rhqoff = 0;

        if (unlikely((packet->numpkt & (MAX_PKT_RECV - 1)) == 0)) {
                if (thread) {
                        cond_resched();
                } else {
                        ret = RCV_PKT_LIMIT;
                        this_cpu_inc(*packet->rcd->dd->rcv_limit);
                }
        }

        packet->rhf_addr = (__le32 *) packet->rcd->rcvhdrq + packet->rhqoff +
                                      packet->rcd->dd->rhf_offset;
        packet->rhf = rhf_to_cpu(packet->rhf_addr);

        return ret;
}

static inline void process_rcv_update(int last, struct hfi1_packet *packet)
{
        /*
         * Update head regs etc., every 16 packets, if not last pkt,
         * to help prevent rcvhdrq overflows, when many packets
         * are processed and queue is nearly full.
         * Don't request an interrupt for intermediate updates.
         */
        if (!last && !(packet->numpkt & 0xf)) {
                update_usrhead(packet->rcd, packet->rhqoff, packet->updegr,
                               packet->etail, 0, 0);
                packet->updegr = 0;
        }
        packet->rcv_flags = 0;
}

static inline void finish_packet(struct hfi1_packet *packet)
{

        /*
         * Nothing we need to free for the packet.
         *
         * The only thing we need to do is a final update and call for an
         * interrupt
         */
        update_usrhead(packet->rcd, packet->rcd->head, packet->updegr,
                       packet->etail, rcv_intr_dynamic, packet->numpkt);

}

static inline void process_rcv_qp_work(struct hfi1_packet *packet)
{

        struct hfi1_ctxtdata *rcd;
        struct hfi1_qp *qp, *nqp;

        rcd = packet->rcd;
        rcd->head = packet->rhqoff;

        /*
         * Iterate over all QPs waiting to respond.
         * The list won't change since the IRQ is only run on one CPU.
         */
        list_for_each_entry_safe(qp, nqp, &rcd->qp_wait_list, rspwait) {
                list_del_init(&qp->rspwait);
                if (qp->r_flags & HFI1_R_RSP_NAK) {
                        qp->r_flags &= ~HFI1_R_RSP_NAK;
                        hfi1_send_rc_ack(rcd, qp, 0);
                }
                if (qp->r_flags & HFI1_R_RSP_SEND) {
                        unsigned long flags;

                        qp->r_flags &= ~HFI1_R_RSP_SEND;
                        spin_lock_irqsave(&qp->s_lock, flags);
                        if (ib_hfi1_state_ops[qp->state] &
                                        HFI1_PROCESS_OR_FLUSH_SEND)
                                hfi1_schedule_send(qp);
                        spin_unlock_irqrestore(&qp->s_lock, flags);
                }
                if (atomic_dec_and_test(&qp->refcount))
                        wake_up(&qp->wait);
        }
}

/*
 * Handle receive interrupts when using the no dma rtail option.
 */
int handle_receive_interrupt_nodma_rtail(struct hfi1_ctxtdata *rcd, int thread)
{
        u32 seq;
        int last = RCV_PKT_OK;
        struct hfi1_packet packet;

        init_packet(rcd, &packet);
        seq = rhf_rcv_seq(packet.rhf);
        if (seq != rcd->seq_cnt) {
                last = RCV_PKT_DONE;
                goto bail;
        }

        prescan_rxq(&packet);

        while (last == RCV_PKT_OK) {
                last = process_rcv_packet(&packet, thread);
                seq = rhf_rcv_seq(packet.rhf);
                if (++rcd->seq_cnt > 13)
                        rcd->seq_cnt = 1;
                if (seq != rcd->seq_cnt)
                        last = RCV_PKT_DONE;
                process_rcv_update(last, &packet);
        }
        process_rcv_qp_work(&packet);
bail:
        finish_packet(&packet);
        return last;
}

int handle_receive_interrupt_dma_rtail(struct hfi1_ctxtdata *rcd, int thread)
{
        u32 hdrqtail;
        int last = RCV_PKT_OK;
        struct hfi1_packet packet;

        init_packet(rcd, &packet);
        hdrqtail = get_rcvhdrtail(rcd);
        if (packet.rhqoff == hdrqtail) {
                last = RCV_PKT_DONE;
                goto bail;
        }
        smp_rmb();  /* prevent speculative reads of dma'ed hdrq */

        prescan_rxq(&packet);

        while (last == RCV_PKT_OK) {
                last = process_rcv_packet(&packet, thread);
                hdrqtail = get_rcvhdrtail(rcd);
                if (packet.rhqoff == hdrqtail)
                        last = RCV_PKT_DONE;
                process_rcv_update(last, &packet);
        }
        process_rcv_qp_work(&packet);
bail:
        finish_packet(&packet);
        return last;
}

static inline void set_all_nodma_rtail(struct hfi1_devdata *dd)
{
        int i;

        for (i = 0; i < dd->first_user_ctxt; i++)
                dd->rcd[i]->do_interrupt =
                        &handle_receive_interrupt_nodma_rtail;
}

static inline void set_all_dma_rtail(struct hfi1_devdata *dd)
{
        int i;

        for (i = 0; i < dd->first_user_ctxt; i++)
                dd->rcd[i]->do_interrupt =
                        &handle_receive_interrupt_dma_rtail;
}

/*
 * handle_receive_interrupt - receive a packet
 * @rcd: the context
 *
 * Called from interrupt handler for errors or receive interrupt.
 * This is the slow path interrupt handler.
 */
int handle_receive_interrupt(struct hfi1_ctxtdata *rcd, int thread)
{
        struct hfi1_devdata *dd = rcd->dd;
        u32 hdrqtail;
        int last = RCV_PKT_OK, needset = 1;
        struct hfi1_packet packet;

        init_packet(rcd, &packet);

        if (!HFI1_CAP_IS_KSET(DMA_RTAIL)) {
                u32 seq = rhf_rcv_seq(packet.rhf);

                if (seq != rcd->seq_cnt) {
                        last = RCV_PKT_DONE;
                        goto bail;
                }
                hdrqtail = 0;
        } else {
                hdrqtail = get_rcvhdrtail(rcd);
                if (packet.rhqoff == hdrqtail) {
                        last = RCV_PKT_DONE;
                        goto bail;
                }
                smp_rmb();  /* prevent speculative reads of dma'ed hdrq */
        }

        prescan_rxq(&packet);

        while (last == RCV_PKT_OK) {

                if (unlikely(dd->do_drop && atomic_xchg(&dd->drop_packet,
                        DROP_PACKET_OFF) == DROP_PACKET_ON)) {
                        dd->do_drop = 0;

                        /* On to the next packet */
                        packet.rhqoff += packet.rsize;
                        packet.rhf_addr = (__le32 *) rcd->rcvhdrq +
                                          packet.rhqoff +
                                          dd->rhf_offset;
                        packet.rhf = rhf_to_cpu(packet.rhf_addr);

                } else {
                        last = process_rcv_packet(&packet, thread);
                }

                if (!HFI1_CAP_IS_KSET(DMA_RTAIL)) {
                        u32 seq = rhf_rcv_seq(packet.rhf);

                        if (++rcd->seq_cnt > 13)
                                rcd->seq_cnt = 1;
                        if (seq != rcd->seq_cnt)
                                last = RCV_PKT_DONE;
                        if (needset) {
                                dd_dev_info(dd,
                                        "Switching to NO_DMA_RTAIL\n");
                                set_all_nodma_rtail(dd);
                                needset = 0;
                        }
                } else {
                        if (packet.rhqoff == hdrqtail)
                                last = RCV_PKT_DONE;
                        if (needset) {
                                dd_dev_info(dd,
                                            "Switching to DMA_RTAIL\n");
                                set_all_dma_rtail(dd);
                                needset = 0;
                        }
                }

                process_rcv_update(last, &packet);
        }

        process_rcv_qp_work(&packet);

bail:
        /*
         * Always write head at end, and setup rcv interrupt, even
         * if no packets were processed.
         */
        finish_packet(&packet);
        return last;
}

/*
 * Convert a given MTU size to the on-wire MAD packet enumeration.
 * Return -1 if the size is invalid.
 */
int mtu_to_enum(u32 mtu, int default_if_bad)
{
        switch (mtu) {
        case     0: return OPA_MTU_0;
        case   256: return OPA_MTU_256;
        case   512: return OPA_MTU_512;
        case  1024: return OPA_MTU_1024;
        case  2048: return OPA_MTU_2048;
        case  4096: return OPA_MTU_4096;
        case  8192: return OPA_MTU_8192;
        case 10240: return OPA_MTU_10240;
        }
        return default_if_bad;
}

u16 enum_to_mtu(int mtu)
{
        switch (mtu) {
        case OPA_MTU_0:     return 0;
        case OPA_MTU_256:   return 256;
        case OPA_MTU_512:   return 512;
        case OPA_MTU_1024:  return 1024;
        case OPA_MTU_2048:  return 2048;
        case OPA_MTU_4096:  return 4096;
        case OPA_MTU_8192:  return 8192;
        case OPA_MTU_10240: return 10240;
        default: return 0xffff;
        }
}

/*
 * set_mtu - set the MTU
 * @ppd: the per port data
 *
 * We can handle "any" incoming size, the issue here is whether we
 * need to restrict our outgoing size.  We do not deal with what happens
 * to programs that are already running when the size changes.
 */
int set_mtu(struct hfi1_pportdata *ppd)
{
        struct hfi1_devdata *dd = ppd->dd;
        int i, drain, ret = 0, is_up = 0;

        ppd->ibmtu = 0;
        for (i = 0; i < ppd->vls_supported; i++)
                if (ppd->ibmtu < dd->vld[i].mtu)
                        ppd->ibmtu = dd->vld[i].mtu;
        ppd->ibmaxlen = ppd->ibmtu + lrh_max_header_bytes(ppd->dd);

        mutex_lock(&ppd->hls_lock);
        if (ppd->host_link_state == HLS_UP_INIT
                        || ppd->host_link_state == HLS_UP_ARMED
                        || ppd->host_link_state == HLS_UP_ACTIVE)
                is_up = 1;

        drain = !is_ax(dd) && is_up;

        if (drain)
                /*
                 * MTU is specified per-VL. To ensure that no packet gets
                 * stuck (due, e.g., to the MTU for the packet's VL being
                 * reduced), empty the per-VL FIFOs before adjusting MTU.
                 */
                ret = stop_drain_data_vls(dd);

        if (ret) {
                dd_dev_err(dd, "%s: cannot stop/drain VLs - refusing to change per-VL MTUs\n",
                           __func__);
                goto err;
        }

        hfi1_set_ib_cfg(ppd, HFI1_IB_CFG_MTU, 0);

        if (drain)
                open_fill_data_vls(dd); /* reopen all VLs */

err:
        mutex_unlock(&ppd->hls_lock);

        return ret;
}

int hfi1_set_lid(struct hfi1_pportdata *ppd, u32 lid, u8 lmc)
{
        struct hfi1_devdata *dd = ppd->dd;

        ppd->lid = lid;
        ppd->lmc = lmc;
        hfi1_set_ib_cfg(ppd, HFI1_IB_CFG_LIDLMC, 0);

        dd_dev_info(dd, "IB%u:%u got a lid: 0x%x\n", dd->unit, ppd->port, lid);

        return 0;
}

/*
 * Following deal with the "obviously simple" task of overriding the state
 * of the LEDs, which normally indicate link physical and logical status.
 * The complications arise in dealing with different hardware mappings
 * and the board-dependent routine being called from interrupts.
 * and then there's the requirement to _flash_ them.
 */
#define LED_OVER_FREQ_SHIFT 8
#define LED_OVER_FREQ_MASK (0xFF<<LED_OVER_FREQ_SHIFT)
/* Below is "non-zero" to force override, but both actual LEDs are off */
#define LED_OVER_BOTH_OFF (8)

static void run_led_override(unsigned long opaque)
{
        struct hfi1_pportdata *ppd = (struct hfi1_pportdata *)opaque;
        struct hfi1_devdata *dd = ppd->dd;
        int timeoff;
        int ph_idx;

        if (!(dd->flags & HFI1_INITTED))
                return;

        ph_idx = ppd->led_override_phase++ & 1;
        ppd->led_override = ppd->led_override_vals[ph_idx];
        timeoff = ppd->led_override_timeoff;

        /*
         * don't re-fire the timer if user asked for it to be off; we let
         * it fire one more time after they turn it off to simplify
         */
        if (ppd->led_override_vals[0] || ppd->led_override_vals[1])
                mod_timer(&ppd->led_override_timer, jiffies + timeoff);
}

void hfi1_set_led_override(struct hfi1_pportdata *ppd, unsigned int val)
{
        struct hfi1_devdata *dd = ppd->dd;
        int timeoff, freq;

        if (!(dd->flags & HFI1_INITTED))
                return;

        /* First check if we are blinking. If not, use 1HZ polling */
        timeoff = HZ;
        freq = (val & LED_OVER_FREQ_MASK) >> LED_OVER_FREQ_SHIFT;

        if (freq) {
                /* For blink, set each phase from one nybble of val */
                ppd->led_override_vals[0] = val & 0xF;
                ppd->led_override_vals[1] = (val >> 4) & 0xF;
                timeoff = (HZ << 4)/freq;
        } else {
                /* Non-blink set both phases the same. */
                ppd->led_override_vals[0] = val & 0xF;
                ppd->led_override_vals[1] = val & 0xF;
        }
        ppd->led_override_timeoff = timeoff;

        /*
         * If the timer has not already been started, do so. Use a "quick"
         * timeout so the function will be called soon, to look at our request.
         */
        if (atomic_inc_return(&ppd->led_override_timer_active) == 1) {
                /* Need to start timer */
                setup_timer(&ppd->led_override_timer, run_led_override,
                                (unsigned long)ppd);

                ppd->led_override_timer.expires = jiffies + 1;
                add_timer(&ppd->led_override_timer);
        } else {
                if (ppd->led_override_vals[0] || ppd->led_override_vals[1])
                        mod_timer(&ppd->led_override_timer, jiffies + 1);
                atomic_dec(&ppd->led_override_timer_active);
        }
}

/**
 * hfi1_reset_device - reset the chip if possible
 * @unit: the device to reset
 *
 * Whether or not reset is successful, we attempt to re-initialize the chip
 * (that is, much like a driver unload/reload).  We clear the INITTED flag
 * so that the various entry points will fail until we reinitialize.  For
 * now, we only allow this if no user contexts are open that use chip resources
 */
int hfi1_reset_device(int unit)
{
        int ret, i;
        struct hfi1_devdata *dd = hfi1_lookup(unit);
        struct hfi1_pportdata *ppd;
        unsigned long flags;
        int pidx;

        if (!dd) {
                ret = -ENODEV;
                goto bail;
        }

        dd_dev_info(dd, "Reset on unit %u requested\n", unit);

        if (!dd->kregbase || !(dd->flags & HFI1_PRESENT)) {
                dd_dev_info(dd,
                        "Invalid unit number %u or not initialized or not present\n",
                        unit);
                ret = -ENXIO;
                goto bail;
        }

        spin_lock_irqsave(&dd->uctxt_lock, flags);
        if (dd->rcd)
                for (i = dd->first_user_ctxt; i < dd->num_rcv_contexts; i++) {
                        if (!dd->rcd[i] || !dd->rcd[i]->cnt)
                                continue;
                        spin_unlock_irqrestore(&dd->uctxt_lock, flags);
                        ret = -EBUSY;
                        goto bail;
                }
        spin_unlock_irqrestore(&dd->uctxt_lock, flags);

        for (pidx = 0; pidx < dd->num_pports; ++pidx) {
                ppd = dd->pport + pidx;
                if (atomic_read(&ppd->led_override_timer_active)) {
                        /* Need to stop LED timer, _then_ shut off LEDs */
                        del_timer_sync(&ppd->led_override_timer);
                        atomic_set(&ppd->led_override_timer_active, 0);
                }

                /* Shut off LEDs after we are sure timer is not running */
                ppd->led_override = LED_OVER_BOTH_OFF;
        }
        if (dd->flags & HFI1_HAS_SEND_DMA)
                sdma_exit(dd);

        hfi1_reset_cpu_counters(dd);

        ret = hfi1_init(dd, 1);

        if (ret)
                dd_dev_err(dd,
                        "Reinitialize unit %u after reset failed with %d\n",
                        unit, ret);
        else
                dd_dev_info(dd, "Reinitialized unit %u after resetting\n",
                        unit);

bail:
        return ret;
}

void handle_eflags(struct hfi1_packet *packet)
{
        struct hfi1_ctxtdata *rcd = packet->rcd;
        u32 rte = rhf_rcv_type_err(packet->rhf);

        dd_dev_err(rcd->dd,
                "receive context %d: rhf 0x%016llx, errs [ %s%s%s%s%s%s%s%s] rte 0x%x\n",
                rcd->ctxt, packet->rhf,
                packet->rhf & RHF_K_HDR_LEN_ERR ? "k_hdr_len " : "",
                packet->rhf & RHF_DC_UNC_ERR ? "dc_unc " : "",
                packet->rhf & RHF_DC_ERR ? "dc " : "",
                packet->rhf & RHF_TID_ERR ? "tid " : "",
                packet->rhf & RHF_LEN_ERR ? "len " : "",
                packet->rhf & RHF_ECC_ERR ? "ecc " : "",
                packet->rhf & RHF_VCRC_ERR ? "vcrc " : "",
                packet->rhf & RHF_ICRC_ERR ? "icrc " : "",
                rte);

        rcv_hdrerr(rcd, rcd->ppd, packet);
}

/*
 * The following functions are called by the interrupt handler. They are type
 * specific handlers for each packet type.
 */
int process_receive_ib(struct hfi1_packet *packet)
{
        trace_hfi1_rcvhdr(packet->rcd->ppd->dd,
                          packet->rcd->ctxt,
                          rhf_err_flags(packet->rhf),
                          RHF_RCV_TYPE_IB,
                          packet->hlen,
                          packet->tlen,
                          packet->updegr,
                          rhf_egr_index(packet->rhf));

        if (unlikely(rhf_err_flags(packet->rhf))) {
                handle_eflags(packet);
                return RHF_RCV_CONTINUE;
        }

        hfi1_ib_rcv(packet);
        return RHF_RCV_CONTINUE;
}

int process_receive_bypass(struct hfi1_packet *packet)
{
        if (unlikely(rhf_err_flags(packet->rhf)))
                handle_eflags(packet);

        dd_dev_err(packet->rcd->dd,
           "Bypass packets are not supported in normal operation. Dropping\n");
        return RHF_RCV_CONTINUE;
}

int process_receive_error(struct hfi1_packet *packet)
{
        handle_eflags(packet);

        if (unlikely(rhf_err_flags(packet->rhf)))
                dd_dev_err(packet->rcd->dd,
                           "Unhandled error packet received. Dropping.\n");

        return RHF_RCV_CONTINUE;
}

int kdeth_process_expected(struct hfi1_packet *packet)
{
        if (unlikely(rhf_err_flags(packet->rhf)))
                handle_eflags(packet);

        dd_dev_err(packet->rcd->dd,
                   "Unhandled expected packet received. Dropping.\n");
        return RHF_RCV_CONTINUE;
}

int kdeth_process_eager(struct hfi1_packet *packet)
{
        if (unlikely(rhf_err_flags(packet->rhf)))
                handle_eflags(packet);

        dd_dev_err(packet->rcd->dd,
                   "Unhandled eager packet received. Dropping.\n");
        return RHF_RCV_CONTINUE;
}

int process_receive_invalid(struct hfi1_packet *packet)
{
        dd_dev_err(packet->rcd->dd, "Invalid packet type %d. Dropping\n",
                rhf_rcv_type(packet->rhf));
        return RHF_RCV_CONTINUE;
}