/*
 * Copyright (c) 2006, 2007, 2009 QLogic Corporation. All rights reserved.
 * Copyright (c) 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 "qib.h"

/**
 * qib_alloc_lkey - allocate an lkey
 * @mr: memory region that this lkey protects
 * @dma_region: 0->normal key, 1->restricted DMA key
 *
 * Returns 0 if successful, otherwise returns -errno.
 *
 * Increments mr reference count as required.
 *
 * Sets the lkey field mr for non-dma regions.
 *
 */

int qib_alloc_lkey(struct rvt_mregion *mr, int dma_region)
{
        unsigned long flags;
        u32 r;
        u32 n;
        int ret = 0;
        struct qib_ibdev *dev = to_idev(mr->pd->device);
        struct rvt_lkey_table *rkt = &dev->lk_table;

        spin_lock_irqsave(&rkt->lock, flags);

        /* special case for dma_mr lkey == 0 */
        if (dma_region) {
                struct rvt_mregion *tmr;

                tmr = rcu_access_pointer(dev->dma_mr);
                if (!tmr) {
                        qib_get_mr(mr);
                        rcu_assign_pointer(dev->dma_mr, mr);
                        mr->lkey_published = 1;
                }
                goto success;
        }

        /* Find the next available LKEY */
        r = rkt->next;
        n = r;
        for (;;) {
                if (rkt->table[r] == NULL)
                        break;
                r = (r + 1) & (rkt->max - 1);
                if (r == n)
                        goto bail;
        }
        rkt->next = (r + 1) & (rkt->max - 1);
        /*
         * Make sure lkey is never zero which is reserved to indicate an
         * unrestricted LKEY.
         */
        rkt->gen++;
        /*
         * bits are capped in qib_verbs.c to insure enough bits
         * for generation number
         */
        mr->lkey = (r << (32 - ib_rvt_lkey_table_size)) |
                ((((1 << (24 - ib_rvt_lkey_table_size)) - 1) & rkt->gen)
                 << 8);
        if (mr->lkey == 0) {
                mr->lkey |= 1 << 8;
                rkt->gen++;
        }
        qib_get_mr(mr);
        rcu_assign_pointer(rkt->table[r], mr);
        mr->lkey_published = 1;
success:
        spin_unlock_irqrestore(&rkt->lock, flags);
out:
        return ret;
bail:
        spin_unlock_irqrestore(&rkt->lock, flags);
        ret = -ENOMEM;
        goto out;
}

/**
 * qib_free_lkey - free an lkey
 * @mr: mr to free from tables
 */
void qib_free_lkey(struct rvt_mregion *mr)
{
        unsigned long flags;
        u32 lkey = mr->lkey;
        u32 r;
        struct qib_ibdev *dev = to_idev(mr->pd->device);
        struct rvt_lkey_table *rkt = &dev->lk_table;

        spin_lock_irqsave(&rkt->lock, flags);
        if (!mr->lkey_published)
                goto out;
        if (lkey == 0)
                RCU_INIT_POINTER(dev->dma_mr, NULL);
        else {
                r = lkey >> (32 - ib_rvt_lkey_table_size);
                RCU_INIT_POINTER(rkt->table[r], NULL);
        }
        qib_put_mr(mr);
        mr->lkey_published = 0;
out:
        spin_unlock_irqrestore(&rkt->lock, flags);
}

/**
 * qib_rkey_ok - check the IB virtual address, length, and RKEY
 * @qp: qp for validation
 * @sge: SGE state
 * @len: length of data
 * @vaddr: virtual address to place data
 * @rkey: rkey to check
 * @acc: access flags
 *
 * Return 1 if successful, otherwise 0.
 *
 * increments the reference count upon success
 */
int qib_rkey_ok(struct rvt_qp *qp, struct rvt_sge *sge,
                u32 len, u64 vaddr, u32 rkey, int acc)
{
        struct rvt_lkey_table *rkt = &to_idev(qp->ibqp.device)->lk_table;
        struct rvt_mregion *mr;
        unsigned n, m;
        size_t off;

        /*
         * We use RKEY == zero for kernel virtual addresses
         * (see qib_get_dma_mr and qib_dma.c).
         */
        rcu_read_lock();
        if (rkey == 0) {
                struct rvt_pd *pd = ibpd_to_rvtpd(qp->ibqp.pd);
                struct qib_ibdev *dev = to_idev(pd->ibpd.device);

                if (pd->user)
                        goto bail;
                mr = rcu_dereference(dev->dma_mr);
                if (!mr)
                        goto bail;
                if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
                        goto bail;
                rcu_read_unlock();

                sge->mr = mr;
                sge->vaddr = (void *) vaddr;
                sge->length = len;
                sge->sge_length = len;
                sge->m = 0;
                sge->n = 0;
                goto ok;
        }

        mr = rcu_dereference(
                rkt->table[(rkey >> (32 - ib_rvt_lkey_table_size))]);
        if (unlikely(!mr || mr->lkey != rkey || qp->ibqp.pd != mr->pd))
                goto bail;

        off = vaddr - mr->iova;
        if (unlikely(vaddr < mr->iova || off + len > mr->length ||
                     (mr->access_flags & acc) == 0))
                goto bail;
        if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
                goto bail;
        rcu_read_unlock();

        off += mr->offset;
        if (mr->page_shift) {
                /*
                page sizes are uniform power of 2 so no loop is necessary
                entries_spanned_by_off is the number of times the loop below
                would have executed.
                */
                size_t entries_spanned_by_off;

                entries_spanned_by_off = off >> mr->page_shift;
                off -= (entries_spanned_by_off << mr->page_shift);
                m = entries_spanned_by_off / RVT_SEGSZ;
                n = entries_spanned_by_off % RVT_SEGSZ;
        } else {
                m = 0;
                n = 0;
                while (off >= mr->map[m]->segs[n].length) {
                        off -= mr->map[m]->segs[n].length;
                        n++;
                        if (n >= RVT_SEGSZ) {
                                m++;
                                n = 0;
                        }
                }
        }
        sge->mr = mr;
        sge->vaddr = mr->map[m]->segs[n].vaddr + off;
        sge->length = mr->map[m]->segs[n].length - off;
        sge->sge_length = len;
        sge->m = m;
        sge->n = n;
ok:
        return 1;
bail:
        rcu_read_unlock();
        return 0;
}