/*
 * Copyright (C) 2015, 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: stable/10/sys/dev/netmap/if_ixl_netmap.h 292096 2015-12-11 12:24:11Z smh $
 *
 * netmap support for: ixl
 *
 * derived from ixgbe
 * netmap support for a network driver.
 * This file contains code but only static or inline functions used
 * by a single driver. To avoid replication of code we just #include
 * it near the beginning of the standard driver.
 * For ixl the file is imported in two places, hence the conditional at the
 * beginning.
 */

#include <net/netmap.h>
#include <sys/selinfo.h>

/*
 * Some drivers may need the following headers. Others
 * already include them by default

#include <vm/vm.h>
#include <vm/pmap.h>

 */
#include <dev/netmap/netmap_kern.h>

int ixl_netmap_txsync(struct netmap_kring *kring, int flags);
int ixl_netmap_rxsync(struct netmap_kring *kring, int flags);

extern int ixl_rx_miss, ixl_rx_miss_bufs, ixl_crcstrip;

#ifdef NETMAP_IXL_MAIN
/*
 * device-specific sysctl variables:
 *
 * ixl_crcstrip: 0: keep CRC in rx frames (default), 1: strip it.
 *	During regular operations the CRC is stripped, but on some
 *	hardware reception of frames not multiple of 64 is slower,
 *	so using crcstrip=0 helps in benchmarks.
 *
 * ixl_rx_miss, ixl_rx_miss_bufs:
 *	count packets that might be missed due to lost interrupts.
 */
SYSCTL_DECL(_dev_netmap);
int ixl_rx_miss, ixl_rx_miss_bufs, ixl_crcstrip;
SYSCTL_INT(_dev_netmap, OID_AUTO, ixl_crcstrip,
    CTLFLAG_RW, &ixl_crcstrip, 0, "strip CRC on rx frames");
SYSCTL_INT(_dev_netmap, OID_AUTO, ixl_rx_miss,
    CTLFLAG_RW, &ixl_rx_miss, 0, "potentially missed rx intr");
SYSCTL_INT(_dev_netmap, OID_AUTO, ixl_rx_miss_bufs,
    CTLFLAG_RW, &ixl_rx_miss_bufs, 0, "potentially missed rx intr bufs");


/*
 * Register/unregister. We are already under netmap lock.
 * Only called on the first register or the last unregister.
 */
static int
ixl_netmap_reg(struct netmap_adapter *na, int onoff)
{
	struct ifnet *ifp = na->ifp;
        struct ixl_vsi  *vsi = ifp->if_softc;
        struct ixl_pf   *pf = (struct ixl_pf *)vsi->back;

	IXL_PF_LOCK(pf);
	ixl_disable_intr(vsi);

	/* Tell the stack that the interface is no longer active */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

	//set_crcstrip(&adapter->hw, onoff);
	/* enable or disable flags and callbacks in na and ifp */
	if (onoff) {
		nm_set_native_flags(na);
	} else {
		nm_clear_native_flags(na);
	}
	ixl_init_locked(pf);	/* also enables intr */
	//set_crcstrip(&adapter->hw, onoff); // XXX why twice ?
	IXL_PF_UNLOCK(pf);
	return (ifp->if_drv_flags & IFF_DRV_RUNNING ? 0 : 1);
}


/*
 * The attach routine, called near the end of ixl_attach(),
 * fills the parameters for netmap_attach() and calls it.
 * It cannot fail, in the worst case (such as no memory)
 * netmap mode will be disabled and the driver will only
 * operate in standard mode.
 */
static void
ixl_netmap_attach(struct ixl_vsi *vsi)
{
	struct netmap_adapter na;

	bzero(&na, sizeof(na));

	na.ifp = vsi->ifp;
	na.na_flags = NAF_BDG_MAYSLEEP;
	// XXX check that queues is set.
	printf("queues is %p\n", vsi->queues);
	if (vsi->queues) {
		na.num_tx_desc = vsi->queues[0].num_desc;
		na.num_rx_desc = vsi->queues[0].num_desc;
	}
	na.nm_txsync = ixl_netmap_txsync;
	na.nm_rxsync = ixl_netmap_rxsync;
	na.nm_register = ixl_netmap_reg;
	na.num_tx_rings = na.num_rx_rings = vsi->num_queues;
	netmap_attach(&na);
}


#else /* !NETMAP_IXL_MAIN, code for ixl_txrx.c */

/*
 * Reconcile kernel and user view of the transmit ring.
 *
 * All information is in the kring.
 * Userspace wants to send packets up to the one before kring->rhead,
 * kernel knows kring->nr_hwcur is the first unsent packet.
 *
 * Here we push packets out (as many as possible), and possibly
 * reclaim buffers from previously completed transmission.
 *
 * The caller (netmap) guarantees that there is only one instance
 * running at any time. Any interference with other driver
 * methods should be handled by the individual drivers.
 */
int
ixl_netmap_txsync(struct netmap_kring *kring, int flags)
{
	struct netmap_adapter *na = kring->na;
	struct ifnet *ifp = na->ifp;
	struct netmap_ring *ring = kring->ring;
	u_int nm_i;	/* index into the netmap ring */
	u_int nic_i;	/* index into the NIC ring */
	u_int n;
	u_int const lim = kring->nkr_num_slots - 1;
	u_int const head = kring->rhead;
	/*
	 * interrupts on every tx packet are expensive so request
	 * them every half ring, or where NS_REPORT is set
	 */
	u_int report_frequency = kring->nkr_num_slots >> 1;

	/* device-specific */
	struct ixl_vsi *vsi = ifp->if_softc;
	struct ixl_queue *que = &vsi->queues[kring->ring_id];
	struct tx_ring *txr = &que->txr;

	bus_dmamap_sync(txr->dma.tag, txr->dma.map,
			BUS_DMASYNC_POSTREAD);

	/*
	 * First part: process new packets to send.
	 * nm_i is the current index in the netmap ring,
	 * nic_i is the corresponding index in the NIC ring.
	 *
	 * If we have packets to send (nm_i != head)
	 * iterate over the netmap ring, fetch length and update
	 * the corresponding slot in the NIC ring. Some drivers also
	 * need to update the buffer's physical address in the NIC slot
	 * even NS_BUF_CHANGED is not set (PNMB computes the addresses).
	 *
	 * The netmap_reload_map() calls is especially expensive,
	 * even when (as in this case) the tag is 0, so do only
	 * when the buffer has actually changed.
	 *
	 * If possible do not set the report/intr bit on all slots,
	 * but only a few times per ring or when NS_REPORT is set.
	 *
	 * Finally, on 10G and faster drivers, it might be useful
	 * to prefetch the next slot and txr entry.
	 */

	nm_i = kring->nr_hwcur;
	if (nm_i != head) {	/* we have new packets to send */
		nic_i = netmap_idx_k2n(kring, nm_i);

		__builtin_prefetch(&ring->slot[nm_i]);
		__builtin_prefetch(&txr->buffers[nic_i]);

		for (n = 0; nm_i != head; n++) {
			struct netmap_slot *slot = &ring->slot[nm_i];
			u_int len = slot->len;
			uint64_t paddr;
			void *addr = PNMB(na, slot, &paddr);

			/* device-specific */
			struct i40e_tx_desc *curr = &txr->base[nic_i];
			struct ixl_tx_buf *txbuf = &txr->buffers[nic_i];
			u64 flags = (slot->flags & NS_REPORT ||
				nic_i == 0 || nic_i == report_frequency) ?
				((u64)I40E_TX_DESC_CMD_RS << I40E_TXD_QW1_CMD_SHIFT) : 0;

			/* prefetch for next round */
			__builtin_prefetch(&ring->slot[nm_i + 1]);
			__builtin_prefetch(&txr->buffers[nic_i + 1]);

			NM_CHECK_ADDR_LEN(na, addr, len);

			if (slot->flags & NS_BUF_CHANGED) {
				/* buffer has changed, reload map */
				netmap_reload_map(na, txr->dma.tag, txbuf->map, addr);
			}
			slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);

			/* Fill the slot in the NIC ring. */
			curr->buffer_addr = htole64(paddr);
			curr->cmd_type_offset_bsz = htole64(
			    ((u64)len << I40E_TXD_QW1_TX_BUF_SZ_SHIFT) |
			    flags |
			    ((u64)I40E_TX_DESC_CMD_EOP << I40E_TXD_QW1_CMD_SHIFT)
			  ); // XXX more ?

			/* make sure changes to the buffer are synced */
			bus_dmamap_sync(txr->dma.tag, txbuf->map,
				BUS_DMASYNC_PREWRITE);

			nm_i = nm_next(nm_i, lim);
			nic_i = nm_next(nic_i, lim);
		}
		kring->nr_hwcur = head;

		/* synchronize the NIC ring */
		bus_dmamap_sync(txr->dma.tag, txr->dma.map,
			BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

		/* (re)start the tx unit up to slot nic_i (excluded) */
		wr32(vsi->hw, txr->tail, nic_i);
	}

	/*
	 * Second part: reclaim buffers for completed transmissions.
	 */
	nic_i = LE32_TO_CPU(*(volatile __le32 *)&txr->base[que->num_desc]);
	if (nic_i != txr->next_to_clean) {
		/* some tx completed, increment avail */
		txr->next_to_clean = nic_i;
		kring->nr_hwtail = nm_prev(netmap_idx_n2k(kring, nic_i), lim);
	}

	nm_txsync_finalize(kring);

	return 0;
}


/*
 * Reconcile kernel and user view of the receive ring.
 * Same as for the txsync, this routine must be efficient.
 * The caller guarantees a single invocations, but races against
 * the rest of the driver should be handled here.
 *
 * On call, kring->rhead is the first packet that userspace wants
 * to keep, and kring->rcur is the wakeup point.
 * The kernel has previously reported packets up to kring->rtail.
 *
 * If (flags & NAF_FORCE_READ) also check for incoming packets irrespective
 * of whether or not we received an interrupt.
 */
int
ixl_netmap_rxsync(struct netmap_kring *kring, int flags)
{
	struct netmap_adapter *na = kring->na;
	struct ifnet *ifp = na->ifp;
	struct netmap_ring *ring = kring->ring;
	u_int nm_i;	/* index into the netmap ring */
	u_int nic_i;	/* index into the NIC ring */
	u_int n;
	u_int const lim = kring->nkr_num_slots - 1;
	u_int const head = nm_rxsync_prologue(kring);
	int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR;

	/* device-specific */
	struct ixl_vsi *vsi = ifp->if_softc;
	struct ixl_queue *que = &vsi->queues[kring->ring_id];
	struct rx_ring *rxr = &que->rxr;

	if (head > lim)
		return netmap_ring_reinit(kring);

	/* XXX check sync modes */
	bus_dmamap_sync(rxr->dma.tag, rxr->dma.map,
			BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);

	/*
	 * First part: import newly received packets.
	 *
	 * nm_i is the index of the next free slot in the netmap ring,
	 * nic_i is the index of the next received packet in the NIC ring,
	 * and they may differ in case if_init() has been called while
	 * in netmap mode. For the receive ring we have
	 *
	 *	nic_i = rxr->next_check;
	 *	nm_i = kring->nr_hwtail (previous)
	 * and
	 *	nm_i == (nic_i + kring->nkr_hwofs) % ring_size
	 *
	 * rxr->next_check is set to 0 on a ring reinit
	 */
	if (netmap_no_pendintr || force_update) {
		int crclen = ixl_crcstrip ? 0 : 4;
		uint16_t slot_flags = kring->nkr_slot_flags;

		nic_i = rxr->next_check; // or also k2n(kring->nr_hwtail)
		nm_i = netmap_idx_n2k(kring, nic_i);

		for (n = 0; ; n++) {
			union i40e_32byte_rx_desc *curr = &rxr->base[nic_i];
			uint64_t qword = le64toh(curr->wb.qword1.status_error_len);
			uint32_t staterr = (qword & I40E_RXD_QW1_STATUS_MASK)
				 >> I40E_RXD_QW1_STATUS_SHIFT;

			if ((staterr & (1<<I40E_RX_DESC_STATUS_DD_SHIFT)) == 0)
				break;
			ring->slot[nm_i].len = ((qword & I40E_RXD_QW1_LENGTH_PBUF_MASK)
			    >> I40E_RXD_QW1_LENGTH_PBUF_SHIFT) - crclen;
			ring->slot[nm_i].flags = slot_flags;
			bus_dmamap_sync(rxr->ptag,
			    rxr->buffers[nic_i].pmap, BUS_DMASYNC_POSTREAD);
			nm_i = nm_next(nm_i, lim);
			nic_i = nm_next(nic_i, lim);
		}
		if (n) { /* update the state variables */
			if (netmap_no_pendintr && !force_update) {
				/* diagnostics */
				ixl_rx_miss ++;
				ixl_rx_miss_bufs += n;
			}
			rxr->next_check = nic_i;
			kring->nr_hwtail = nm_i;
		}
		kring->nr_kflags &= ~NKR_PENDINTR;
	}

	/*
	 * Second part: skip past packets that userspace has released.
	 * (kring->nr_hwcur to head excluded),
	 * and make the buffers available for reception.
	 * As usual nm_i is the index in the netmap ring,
	 * nic_i is the index in the NIC ring, and
	 * nm_i == (nic_i + kring->nkr_hwofs) % ring_size
	 */
	nm_i = kring->nr_hwcur;
	if (nm_i != head) {
		nic_i = netmap_idx_k2n(kring, nm_i);
		for (n = 0; nm_i != head; n++) {
			struct netmap_slot *slot = &ring->slot[nm_i];
			uint64_t paddr;
			void *addr = PNMB(na, slot, &paddr);

			union i40e_32byte_rx_desc *curr = &rxr->base[nic_i];
			struct ixl_rx_buf *rxbuf = &rxr->buffers[nic_i];

			if (addr == NETMAP_BUF_BASE(na)) /* bad buf */
				goto ring_reset;

			if (slot->flags & NS_BUF_CHANGED) {
				/* buffer has changed, reload map */
				netmap_reload_map(na, rxr->ptag, rxbuf->pmap, addr);
				slot->flags &= ~NS_BUF_CHANGED;
			}
			curr->read.pkt_addr = htole64(paddr);
			curr->read.hdr_addr = 0; // XXX needed
			bus_dmamap_sync(rxr->ptag, rxbuf->pmap,
			    BUS_DMASYNC_PREREAD);
			nm_i = nm_next(nm_i, lim);
			nic_i = nm_next(nic_i, lim);
		}
		kring->nr_hwcur = head;

		bus_dmamap_sync(rxr->dma.tag, rxr->dma.map,
		    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
		/*
		 * IMPORTANT: we must leave one free slot in the ring,
		 * so move nic_i back by one unit
		 */
		nic_i = nm_prev(nic_i, lim);
		wr32(vsi->hw, rxr->tail, nic_i);
	}

	/* tell userspace that there might be new packets */
	nm_rxsync_finalize(kring);

	return 0;

ring_reset:
	return netmap_ring_reinit(kring);
}

#endif /* !NETMAP_IXL_MAIN */

/* end of file */