/*
 * Copyright (c) 2012, 2013 Intel Corporation.  All rights reserved.
 * Copyright (c) 2006 - 2012 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 <linux/err.h>
#include <linux/vmalloc.h>
#include <rdma/rdma_vt.h>
#ifdef CONFIG_DEBUG_FS
#include <linux/seq_file.h>
#endif

#include "qib.h"

/*
 * mask field which was present in now deleted qib_qpn_table
 * is not present in rvt_qpn_table. Defining the same field
 * as qpt_mask here instead of adding the mask field to
 * rvt_qpn_table.
 */
u16 qpt_mask;

static inline unsigned mk_qpn(struct rvt_qpn_table *qpt,
			      struct rvt_qpn_map *map, unsigned off)
{
	return (map - qpt->map) * RVT_BITS_PER_PAGE + off;
}

static inline unsigned find_next_offset(struct rvt_qpn_table *qpt,
					struct rvt_qpn_map *map, unsigned off,
					unsigned n)
{
	if (qpt_mask) {
		off++;
		if (((off & qpt_mask) >> 1) >= n)
			off = (off | qpt_mask) + 2;
	} else {
		off = find_next_zero_bit(map->page, RVT_BITS_PER_PAGE, off);
	}
	return off;
}

/*
 * Convert the AETH credit code into the number of credits.
 */
static u32 credit_table[31] = {
	0,                      /* 0 */
	1,                      /* 1 */
	2,                      /* 2 */
	3,                      /* 3 */
	4,                      /* 4 */
	6,                      /* 5 */
	8,                      /* 6 */
	12,                     /* 7 */
	16,                     /* 8 */
	24,                     /* 9 */
	32,                     /* A */
	48,                     /* B */
	64,                     /* C */
	96,                     /* D */
	128,                    /* E */
	192,                    /* F */
	256,                    /* 10 */
	384,                    /* 11 */
	512,                    /* 12 */
	768,                    /* 13 */
	1024,                   /* 14 */
	1536,                   /* 15 */
	2048,                   /* 16 */
	3072,                   /* 17 */
	4096,                   /* 18 */
	6144,                   /* 19 */
	8192,                   /* 1A */
	12288,                  /* 1B */
	16384,                  /* 1C */
	24576,                  /* 1D */
	32768                   /* 1E */
};

static void get_map_page(struct rvt_qpn_table *qpt, struct rvt_qpn_map *map,
			 gfp_t gfp)
{
	unsigned long page = get_zeroed_page(gfp);

	/*
	 * Free the page if someone raced with us installing it.
	 */

	spin_lock(&qpt->lock);
	if (map->page)
		free_page(page);
	else
		map->page = (void *)page;
	spin_unlock(&qpt->lock);
}

/*
 * Allocate the next available QPN or
 * zero/one for QP type IB_QPT_SMI/IB_QPT_GSI.
 */
int qib_alloc_qpn(struct rvt_dev_info *rdi, struct rvt_qpn_table *qpt,
		  enum ib_qp_type type, u8 port, gfp_t gfp)
{
	u32 i, offset, max_scan, qpn;
	struct rvt_qpn_map *map;
	u32 ret;
	struct qib_ibdev *verbs_dev = container_of(rdi, struct qib_ibdev, rdi);
	struct qib_devdata *dd = container_of(verbs_dev, struct qib_devdata,
					      verbs_dev);

	if (type == IB_QPT_SMI || type == IB_QPT_GSI) {
		unsigned n;

		ret = type == IB_QPT_GSI;
		n = 1 << (ret + 2 * (port - 1));
		spin_lock(&qpt->lock);
		if (qpt->flags & n)
			ret = -EINVAL;
		else
			qpt->flags |= n;
		spin_unlock(&qpt->lock);
		goto bail;
	}

	qpn = qpt->last + 2;
	if (qpn >= RVT_QPN_MAX)
		qpn = 2;
	if (qpt_mask && ((qpn & qpt_mask) >> 1) >= dd->n_krcv_queues)
		qpn = (qpn | qpt_mask) + 2;
	offset = qpn & RVT_BITS_PER_PAGE_MASK;
	map = &qpt->map[qpn / RVT_BITS_PER_PAGE];
	max_scan = qpt->nmaps - !offset;
	for (i = 0;;) {
		if (unlikely(!map->page)) {
			get_map_page(qpt, map, gfp);
			if (unlikely(!map->page))
				break;
		}
		do {
			if (!test_and_set_bit(offset, map->page)) {
				qpt->last = qpn;
				ret = qpn;
				goto bail;
			}
			offset = find_next_offset(qpt, map, offset,
				dd->n_krcv_queues);
			qpn = mk_qpn(qpt, map, offset);
			/*
			 * This test differs from alloc_pidmap().
			 * If find_next_offset() does find a zero
			 * bit, we don't need to check for QPN
			 * wrapping around past our starting QPN.
			 * We just need to be sure we don't loop
			 * forever.
			 */
		} while (offset < RVT_BITS_PER_PAGE && qpn < RVT_QPN_MAX);
		/*
		 * In order to keep the number of pages allocated to a
		 * minimum, we scan the all existing pages before increasing
		 * the size of the bitmap table.
		 */
		if (++i > max_scan) {
			if (qpt->nmaps == RVT_QPNMAP_ENTRIES)
				break;
			map = &qpt->map[qpt->nmaps++];
			offset = 0;
		} else if (map < &qpt->map[qpt->nmaps]) {
			++map;
			offset = 0;
		} else {
			map = &qpt->map[0];
			offset = 2;
		}
		qpn = mk_qpn(qpt, map, offset);
	}

	ret = -ENOMEM;

bail:
	return ret;
}

/**
 * qib_free_all_qps - check for QPs still in use
 */
unsigned qib_free_all_qps(struct rvt_dev_info *rdi)
{
	struct qib_ibdev *verbs_dev = container_of(rdi, struct qib_ibdev, rdi);
	struct qib_devdata *dd = container_of(verbs_dev, struct qib_devdata,
					      verbs_dev);
	unsigned n, qp_inuse = 0;

	for (n = 0; n < dd->num_pports; n++) {
		struct qib_ibport *ibp = &dd->pport[n].ibport_data;

		rcu_read_lock();
		if (rcu_dereference(ibp->rvp.qp[0]))
			qp_inuse++;
		if (rcu_dereference(ibp->rvp.qp[1]))
			qp_inuse++;
		rcu_read_unlock();
	}
	return qp_inuse;
}

void qib_notify_qp_reset(struct rvt_qp *qp)
{
	struct qib_qp_priv *priv = qp->priv;

	atomic_set(&priv->s_dma_busy, 0);
}

void qib_notify_error_qp(struct rvt_qp *qp)
{
	struct qib_qp_priv *priv = qp->priv;
	struct qib_ibdev *dev = to_idev(qp->ibqp.device);

	spin_lock(&dev->rdi.pending_lock);
	if (!list_empty(&priv->iowait) && !(qp->s_flags & RVT_S_BUSY)) {
		qp->s_flags &= ~RVT_S_ANY_WAIT_IO;
		list_del_init(&priv->iowait);
	}
	spin_unlock(&dev->rdi.pending_lock);

	if (!(qp->s_flags & RVT_S_BUSY)) {
		qp->s_hdrwords = 0;
		if (qp->s_rdma_mr) {
			rvt_put_mr(qp->s_rdma_mr);
			qp->s_rdma_mr = NULL;
		}
		if (priv->s_tx) {
			qib_put_txreq(priv->s_tx);
			priv->s_tx = NULL;
		}
	}
}

static int mtu_to_enum(u32 mtu)
{
	int enum_mtu;

	switch (mtu) {
	case 4096:
		enum_mtu = IB_MTU_4096;
		break;
	case 2048:
		enum_mtu = IB_MTU_2048;
		break;
	case 1024:
		enum_mtu = IB_MTU_1024;
		break;
	case 512:
		enum_mtu = IB_MTU_512;
		break;
	case 256:
		enum_mtu = IB_MTU_256;
		break;
	default:
		enum_mtu = IB_MTU_2048;
	}
	return enum_mtu;
}

int qib_get_pmtu_from_attr(struct rvt_dev_info *rdi, struct rvt_qp *qp,
			   struct ib_qp_attr *attr)
{
	int mtu, pmtu, pidx = qp->port_num - 1;
	struct qib_ibdev *verbs_dev = container_of(rdi, struct qib_ibdev, rdi);
	struct qib_devdata *dd = container_of(verbs_dev, struct qib_devdata,
					      verbs_dev);
	mtu = ib_mtu_enum_to_int(attr->path_mtu);
	if (mtu == -1)
		return -EINVAL;

	if (mtu > dd->pport[pidx].ibmtu)
		pmtu = mtu_to_enum(dd->pport[pidx].ibmtu);
	else
		pmtu = attr->path_mtu;
	return pmtu;
}

int qib_mtu_to_path_mtu(u32 mtu)
{
	return mtu_to_enum(mtu);
}

u32 qib_mtu_from_qp(struct rvt_dev_info *rdi, struct rvt_qp *qp, u32 pmtu)
{
	return ib_mtu_enum_to_int(pmtu);
}

/**
 * qib_compute_aeth - compute the AETH (syndrome + MSN)
 * @qp: the queue pair to compute the AETH for
 *
 * Returns the AETH.
 */
__be32 qib_compute_aeth(struct rvt_qp *qp)
{
	u32 aeth = qp->r_msn & QIB_MSN_MASK;

	if (qp->ibqp.srq) {
		/*
		 * Shared receive queues don't generate credits.
		 * Set the credit field to the invalid value.
		 */
		aeth |= QIB_AETH_CREDIT_INVAL << QIB_AETH_CREDIT_SHIFT;
	} else {
		u32 min, max, x;
		u32 credits;
		struct rvt_rwq *wq = qp->r_rq.wq;
		u32 head;
		u32 tail;

		/* sanity check pointers before trusting them */
		head = wq->head;
		if (head >= qp->r_rq.size)
			head = 0;
		tail = wq->tail;
		if (tail >= qp->r_rq.size)
			tail = 0;
		/*
		 * Compute the number of credits available (RWQEs).
		 * XXX Not holding the r_rq.lock here so there is a small
		 * chance that the pair of reads are not atomic.
		 */
		credits = head - tail;
		if ((int)credits < 0)
			credits += qp->r_rq.size;
		/*
		 * Binary search the credit table to find the code to
		 * use.
		 */
		min = 0;
		max = 31;
		for (;;) {
			x = (min + max) / 2;
			if (credit_table[x] == credits)
				break;
			if (credit_table[x] > credits)
				max = x;
			else if (min == x)
				break;
			else
				min = x;
		}
		aeth |= x << QIB_AETH_CREDIT_SHIFT;
	}
	return cpu_to_be32(aeth);
}

void *qib_qp_priv_alloc(struct rvt_dev_info *rdi, struct rvt_qp *qp, gfp_t gfp)
{
	struct qib_qp_priv *priv;

	priv = kzalloc(sizeof(*priv), gfp);
	if (!priv)
		return ERR_PTR(-ENOMEM);
	priv->owner = qp;

	priv->s_hdr = kzalloc(sizeof(*priv->s_hdr), gfp);
	if (!priv->s_hdr) {
		kfree(priv);
		return ERR_PTR(-ENOMEM);
	}
	init_waitqueue_head(&priv->wait_dma);
	INIT_WORK(&priv->s_work, _qib_do_send);
	INIT_LIST_HEAD(&priv->iowait);

	return priv;
}

void qib_qp_priv_free(struct rvt_dev_info *rdi, struct rvt_qp *qp)
{
	struct qib_qp_priv *priv = qp->priv;

	kfree(priv->s_hdr);
	kfree(priv);
}

void qib_stop_send_queue(struct rvt_qp *qp)
{
	struct qib_qp_priv *priv = qp->priv;

	cancel_work_sync(&priv->s_work);
	del_timer_sync(&qp->s_timer);
}

void qib_quiesce_qp(struct rvt_qp *qp)
{
	struct qib_qp_priv *priv = qp->priv;

	wait_event(priv->wait_dma, !atomic_read(&priv->s_dma_busy));
	if (priv->s_tx) {
		qib_put_txreq(priv->s_tx);
		priv->s_tx = NULL;
	}
}

void qib_flush_qp_waiters(struct rvt_qp *qp)
{
	struct qib_qp_priv *priv = qp->priv;
	struct qib_ibdev *dev = to_idev(qp->ibqp.device);

	spin_lock(&dev->rdi.pending_lock);
	if (!list_empty(&priv->iowait))
		list_del_init(&priv->iowait);
	spin_unlock(&dev->rdi.pending_lock);
}

/**
 * qib_get_credit - flush the send work queue of a QP
 * @qp: the qp who's send work queue to flush
 * @aeth: the Acknowledge Extended Transport Header
 *
 * The QP s_lock should be held.
 */
void qib_get_credit(struct rvt_qp *qp, u32 aeth)
{
	u32 credit = (aeth >> QIB_AETH_CREDIT_SHIFT) & QIB_AETH_CREDIT_MASK;

	/*
	 * If the credit is invalid, we can send
	 * as many packets as we like.  Otherwise, we have to
	 * honor the credit field.
	 */
	if (credit == QIB_AETH_CREDIT_INVAL) {
		if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) {
			qp->s_flags |= RVT_S_UNLIMITED_CREDIT;
			if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) {
				qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT;
				qib_schedule_send(qp);
			}
		}
	} else if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) {
		/* Compute new LSN (i.e., MSN + credit) */
		credit = (aeth + credit_table[credit]) & QIB_MSN_MASK;
		if (qib_cmp24(credit, qp->s_lsn) > 0) {
			qp->s_lsn = credit;
			if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) {
				qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT;
				qib_schedule_send(qp);
			}
		}
	}
}

/**
 * qib_check_send_wqe - validate wr/wqe
 * @qp - The qp
 * @wqe - The built wqe
 *
 * validate wr/wqe.  This is called
 * prior to inserting the wqe into
 * the ring but after the wqe has been
 * setup.
 *
 * Returns 1 to force direct progress, 0 otherwise, -EINVAL on failure
 */
int qib_check_send_wqe(struct rvt_qp *qp,
		       struct rvt_swqe *wqe)
{
	struct rvt_ah *ah;
	int ret = 0;

	switch (qp->ibqp.qp_type) {
	case IB_QPT_RC:
	case IB_QPT_UC:
		if (wqe->length > 0x80000000U)
			return -EINVAL;
		break;
	case IB_QPT_SMI:
	case IB_QPT_GSI:
	case IB_QPT_UD:
		ah = ibah_to_rvtah(wqe->ud_wr.ah);
		if (wqe->length > (1 << ah->log_pmtu))
			return -EINVAL;
		/* progress hint */
		ret = 1;
		break;
	default:
		break;
	}
	return ret;
}

#ifdef CONFIG_DEBUG_FS

struct qib_qp_iter {
	struct qib_ibdev *dev;
	struct rvt_qp *qp;
	int n;
};

struct qib_qp_iter *qib_qp_iter_init(struct qib_ibdev *dev)
{
	struct qib_qp_iter *iter;

	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
	if (!iter)
		return NULL;

	iter->dev = dev;
	if (qib_qp_iter_next(iter)) {
		kfree(iter);
		return NULL;
	}

	return iter;
}

int qib_qp_iter_next(struct qib_qp_iter *iter)
{
	struct qib_ibdev *dev = iter->dev;
	int n = iter->n;
	int ret = 1;
	struct rvt_qp *pqp = iter->qp;
	struct rvt_qp *qp;

	for (; n < dev->rdi.qp_dev->qp_table_size; n++) {
		if (pqp)
			qp = rcu_dereference(pqp->next);
		else
			qp = rcu_dereference(dev->rdi.qp_dev->qp_table[n]);
		pqp = qp;
		if (qp) {
			iter->qp = qp;
			iter->n = n;
			return 0;
		}
	}
	return ret;
}

static const char * const qp_type_str[] = {
	"SMI", "GSI", "RC", "UC", "UD",
};

void qib_qp_iter_print(struct seq_file *s, struct qib_qp_iter *iter)
{
	struct rvt_swqe *wqe;
	struct rvt_qp *qp = iter->qp;
	struct qib_qp_priv *priv = qp->priv;

	wqe = rvt_get_swqe_ptr(qp, qp->s_last);
	seq_printf(s,
		   "N %d QP%u %s %u %u %u f=%x %u %u %u %u %u PSN %x %x %x %x %x (%u %u %u %u %u %u) QP%u LID %x\n",
		   iter->n,
		   qp->ibqp.qp_num,
		   qp_type_str[qp->ibqp.qp_type],
		   qp->state,
		   wqe->wr.opcode,
		   qp->s_hdrwords,
		   qp->s_flags,
		   atomic_read(&priv->s_dma_busy),
		   !list_empty(&priv->iowait),
		   qp->timeout,
		   wqe->ssn,
		   qp->s_lsn,
		   qp->s_last_psn,
		   qp->s_psn, qp->s_next_psn,
		   qp->s_sending_psn, qp->s_sending_hpsn,
		   qp->s_last, qp->s_acked, qp->s_cur,
		   qp->s_tail, qp->s_head, qp->s_size,
		   qp->remote_qpn,
		   qp->remote_ah_attr.dlid);
}

#endif