/*
 * Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

/*
 * $FreeBSD$
 * $Id: if_em_netmap.h 9802 2011-12-02 18:42:37Z luigi $
 *
 * netmap changes for if_em.
 *
 * For structure and details on the individual functions please see
 * ixgbe_netmap.h
 */

#include <net/netmap.h>
#include <sys/selinfo.h>
#include <vm/vm.h>
#include <vm/pmap.h>    /* vtophys ? */
#include <dev/netmap/netmap_kern.h>

static void	em_netmap_block_tasks(struct adapter *);
static void	em_netmap_unblock_tasks(struct adapter *);
static int	em_netmap_reg(struct ifnet *, int onoff);
static int	em_netmap_txsync(struct ifnet *, u_int, int);
static int	em_netmap_rxsync(struct ifnet *, u_int, int);
static void	em_netmap_lock_wrapper(struct ifnet *, int, u_int);

static void
em_netmap_attach(struct adapter *adapter)
{
	struct netmap_adapter na;

	bzero(&na, sizeof(na));

	na.ifp = adapter->ifp;
	na.separate_locks = 1;
	na.num_tx_desc = adapter->num_tx_desc;
	na.num_rx_desc = adapter->num_rx_desc;
	na.nm_txsync = em_netmap_txsync;
	na.nm_rxsync = em_netmap_rxsync;
	na.nm_lock = em_netmap_lock_wrapper;
	na.nm_register = em_netmap_reg;
	netmap_attach(&na, adapter->num_queues);
}


/*
 * wrapper to export locks to the generic code
 */
static void
em_netmap_lock_wrapper(struct ifnet *ifp, int what, u_int queueid)
{
	struct adapter *adapter = ifp->if_softc;

	ASSERT(queueid < adapter->num_queues);
	switch (what) {
	case NETMAP_CORE_LOCK:
		EM_CORE_LOCK(adapter);
		break;
	case NETMAP_CORE_UNLOCK:
		EM_CORE_UNLOCK(adapter);
		break;
	case NETMAP_TX_LOCK:
		EM_TX_LOCK(&adapter->tx_rings[queueid]);
		break;
	case NETMAP_TX_UNLOCK:
		EM_TX_UNLOCK(&adapter->tx_rings[queueid]);
		break;
	case NETMAP_RX_LOCK:
		EM_RX_LOCK(&adapter->rx_rings[queueid]);
		break;
	case NETMAP_RX_UNLOCK:
		EM_RX_UNLOCK(&adapter->rx_rings[queueid]);
		break;
	}
}


// XXX do we need to block/unblock the tasks ?
static void
em_netmap_block_tasks(struct adapter *adapter)
{
	if (adapter->msix > 1) { /* MSIX */
		int i;
		struct tx_ring *txr = adapter->tx_rings;
		struct rx_ring *rxr = adapter->rx_rings;

		for (i = 0; i < adapter->num_queues; i++, txr++, rxr++) {
			taskqueue_block(txr->tq);
			taskqueue_drain(txr->tq, &txr->tx_task);
			taskqueue_block(rxr->tq);
			taskqueue_drain(rxr->tq, &rxr->rx_task);
		}
	} else {	/* legacy */
		taskqueue_block(adapter->tq);
		taskqueue_drain(adapter->tq, &adapter->link_task);
		taskqueue_drain(adapter->tq, &adapter->que_task);
	}
}


static void
em_netmap_unblock_tasks(struct adapter *adapter)
{
	if (adapter->msix > 1) {
		struct tx_ring *txr = adapter->tx_rings;
		struct rx_ring *rxr = adapter->rx_rings;
		int i;

		for (i = 0; i < adapter->num_queues; i++) {
			taskqueue_unblock(txr->tq);
			taskqueue_unblock(rxr->tq);
		}
	} else { /* legacy */
		taskqueue_unblock(adapter->tq);
	}
}

/*
 * register-unregister routine
 */
static int
em_netmap_reg(struct ifnet *ifp, int onoff)
{
	struct adapter *adapter = ifp->if_softc;
	struct netmap_adapter *na = NA(ifp);
	int error = 0;

	if (na == NULL)
		return EINVAL;	/* no netmap support here */

	em_disable_intr(adapter);

	/* Tell the stack that the interface is no longer active */
	ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);

	em_netmap_block_tasks(adapter);

	if (onoff) {
		ifp->if_capenable |= IFCAP_NETMAP;

		na->if_transmit = ifp->if_transmit;
		ifp->if_transmit = netmap_start;

		em_init_locked(adapter);
		if ((ifp->if_drv_flags & (IFF_DRV_RUNNING | IFF_DRV_OACTIVE)) == 0) {
			error = ENOMEM;
			goto fail;
		}
	} else {
fail:
		/* restore if_transmit */
		ifp->if_transmit = na->if_transmit;
		ifp->if_capenable &= ~IFCAP_NETMAP;
		em_init_locked(adapter);	/* also enable intr */
	}
	em_netmap_unblock_tasks(adapter);
	return (error);
}

/*
 * Reconcile hardware and user view of the transmit ring.
 */
static int
em_netmap_txsync(struct ifnet *ifp, u_int ring_nr, int do_lock)
{
	struct adapter *adapter = ifp->if_softc;
	struct tx_ring *txr = &adapter->tx_rings[ring_nr];
	struct netmap_adapter *na = NA(adapter->ifp);
	struct netmap_kring *kring = &na->tx_rings[ring_nr];
	struct netmap_ring *ring = kring->ring;
	int j, k, l, n = 0, lim = kring->nkr_num_slots - 1;

	/* generate an interrupt approximately every half ring */
	int report_frequency = kring->nkr_num_slots >> 1;

	k = ring->cur;
	if (k > lim)
		return netmap_ring_reinit(kring);

	if (do_lock)
		EM_TX_LOCK(txr);
	bus_dmamap_sync(txr->txdma.dma_tag, txr->txdma.dma_map,
			BUS_DMASYNC_POSTREAD);

	/* check for new packets to send.
	 * j indexes the netmap ring, l indexes the nic ring, and
	 *	j = kring->nr_hwcur, l = E1000_TDT (not tracked),
	 *	j == (l + kring->nkr_hwofs) % ring_size
	 */
	j = kring->nr_hwcur;
	if (j != k) {	/* we have packets to send */
		l = j - kring->nkr_hwofs;
		if (l < 0)
			l += lim + 1;
		while (j != k) {
			struct netmap_slot *slot = &ring->slot[j];
			struct e1000_tx_desc *curr = &txr->tx_base[l];
			struct em_buffer *txbuf = &txr->tx_buffers[l];
			int flags = ((slot->flags & NS_REPORT) ||
				j == 0 || j == report_frequency) ?
					E1000_TXD_CMD_RS : 0;
			uint64_t paddr;
			void *addr = PNMB(slot, &paddr);
			int len = slot->len;
			if (addr == netmap_buffer_base || len > NETMAP_BUF_SIZE) {
				if (do_lock)
					EM_TX_UNLOCK(txr);
				return netmap_ring_reinit(kring);
			}

			slot->flags &= ~NS_REPORT;
			curr->upper.data = 0;
			curr->lower.data = 
			    htole32(adapter->txd_cmd | len |
				(E1000_TXD_CMD_EOP | flags) );
			if (slot->flags & NS_BUF_CHANGED) {
				curr->buffer_addr = htole64(paddr);
				/* buffer has changed, reload map */
				netmap_reload_map(txr->txtag, txbuf->map, addr);
				slot->flags &= ~NS_BUF_CHANGED;
			}

			bus_dmamap_sync(txr->txtag, txbuf->map,
				BUS_DMASYNC_PREWRITE);
			j = (j == lim) ? 0 : j + 1;
			l = (l == lim) ? 0 : l + 1;
			n++;
		}
		kring->nr_hwcur = k;

		/* decrease avail by number of sent packets */
		kring->nr_hwavail -= n;

		bus_dmamap_sync(txr->txdma.dma_tag, txr->txdma.dma_map,
		    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

		E1000_WRITE_REG(&adapter->hw, E1000_TDT(txr->me), l);
	}

	if (n == 0 || kring->nr_hwavail < 1) {
		int delta;

		/* record completed transmissions using THD. */
		l = E1000_READ_REG(&adapter->hw, E1000_TDH(ring_nr));
		if (l >= kring->nkr_num_slots) { /* XXX can happen */
			D("TDH wrap %d", l);
			l -= kring->nkr_num_slots;
		}
		delta = l - txr->next_to_clean;
		if (delta) {
			/* some completed, increment hwavail. */
			if (delta < 0)
				delta += kring->nkr_num_slots;
			txr->next_to_clean = l;
			kring->nr_hwavail += delta;
		}
	}
	/* update avail to what the hardware knows */
	ring->avail = kring->nr_hwavail;

	if (do_lock)
		EM_TX_UNLOCK(txr);
	return 0;
}

/*
 * Reconcile kernel and user view of the receive ring.
 */
static int
em_netmap_rxsync(struct ifnet *ifp, u_int ring_nr, int do_lock)
{
	struct adapter *adapter = ifp->if_softc;
	struct rx_ring *rxr = &adapter->rx_rings[ring_nr];
	struct netmap_adapter *na = NA(adapter->ifp);
	struct netmap_kring *kring = &na->rx_rings[ring_nr];
	struct netmap_ring *ring = kring->ring;
	int j, k, l, n, lim = kring->nkr_num_slots - 1;

	k = ring->cur;
	if (k > lim)
		return netmap_ring_reinit(kring);
 
	if (do_lock)
		EM_RX_LOCK(rxr);
	/* XXX check sync modes */
	bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map,
			BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);

	/* import newly received packets into the netmap ring.
	 * j is an index in the netmap ring, l in the NIC ring, and
	 *	j = (kring->nr_hwcur + kring->nr_hwavail) % ring_size
	 *	l = rxr->next_to_check;
	 * and
	 *	j == (l + kring->nkr_hwofs) % ring_size
	 */
	l = rxr->next_to_check;
	j = l + kring->nkr_hwofs;
	/* here nkr_hwofs can be negative so must check for j < 0 */
	if (j < 0)
		j += lim + 1;
	else if (j > lim)
		j -= lim + 1;
	for (n = 0; ; n++) {
		struct e1000_rx_desc *curr = &rxr->rx_base[l];

		if ((curr->status & E1000_RXD_STAT_DD) == 0)
			break;
		ring->slot[j].len = le16toh(curr->length);
		bus_dmamap_sync(rxr->rxtag, rxr->rx_buffers[l].map,
			BUS_DMASYNC_POSTREAD);
		j = (j == lim) ? 0 : j + 1;
		/* make sure next_to_refresh follows next_to_check */
		rxr->next_to_refresh = l;	// XXX
		l = (l == lim) ? 0 : l + 1;
	}
	if (n) {
		rxr->next_to_check = l;
		kring->nr_hwavail += n;
	}

	/* skip past packets that userspace has already processed */
	j = kring->nr_hwcur;
	if (j != k) { /* userspace has read some packets. */
		n = 0;
		l = j - kring->nkr_hwofs; /* NIC ring index */
		/* here nkr_hwofs can be negative so check for l > lim */
		if (l < 0)
			l += lim + 1;
		else if (l > lim)
			l -= lim + 1;
		while (j != k) {
			struct netmap_slot *slot = &ring->slot[j];
			struct e1000_rx_desc *curr = &rxr->rx_base[l];
			struct em_buffer *rxbuf = &rxr->rx_buffers[l];
			uint64_t paddr;
			void *addr = PNMB(slot, &paddr);

			if (addr == netmap_buffer_base) { /* bad buf */
				if (do_lock)
					EM_RX_UNLOCK(rxr);
				return netmap_ring_reinit(kring);
			}

			curr->status = 0;
			if (slot->flags & NS_BUF_CHANGED) {
				curr->buffer_addr = htole64(paddr);
				/* buffer has changed, reload map */
				netmap_reload_map(rxr->rxtag, rxbuf->map, addr);
				slot->flags &= ~NS_BUF_CHANGED;
			}

			bus_dmamap_sync(rxr->rxtag, rxbuf->map,
			    BUS_DMASYNC_PREREAD);

			j = (j == lim) ? 0 : j + 1;
			l = (l == lim) ? 0 : l + 1;
			n++;
		}
		kring->nr_hwavail -= n;
		kring->nr_hwcur = k;
		bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map,
		    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
		/*
		 * IMPORTANT: we must leave one free slot in the ring,
		 * so move l back by one unit
		 */
		l = (l == 0) ? lim : l - 1;
		E1000_WRITE_REG(&adapter->hw, E1000_RDT(rxr->me), l);
	}
	/* tell userspace that there are new packets */
	ring->avail = kring->nr_hwavail ;
	if (do_lock)
		EM_RX_UNLOCK(rxr);
	return 0;
}