text: /*
   * Copyright (C) 2011-2014 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: head/sys/dev/netmap/if_lem_netmap.h 271849 2014-09-19 03:51:26Z glebius $
   *
   * netmap support for: lem
   *
   * For details on netmap support please see ixgbe_netmap.h
   */
  
  
  #include <net/netmap.h>
  #include <sys/selinfo.h>
  #include <dev/netmap/netmap_kern.h>
  
  /*
   * Register/unregister. We are already under netmap lock.
   */
  static int
  lem_netmap_reg(struct netmap_adapter *na, int onoff)
  {
  	struct ifnet *ifp = na->ifp;
  	struct adapter *adapter = ifp->if_softc;
  
  	EM_CORE_LOCK(adapter);
  
  	lem_disable_intr(adapter);
  
  	/* Tell the stack that the interface is no longer active */
  	ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
  
  #ifndef EM_LEGACY_IRQ // XXX do we need this ?
  	taskqueue_block(adapter->tq);
  	taskqueue_drain(adapter->tq, &adapter->rxtx_task);
  	taskqueue_drain(adapter->tq, &adapter->link_task);
  #endif /* !EM_LEGCY_IRQ */
  
  	/* enable or disable flags and callbacks in na and ifp */
  	if (onoff) {
  		nm_set_native_flags(na);
  	} else {
  		nm_clear_native_flags(na);
  	}
  	lem_init_locked(adapter);	/* also enable intr */
  
  #ifndef EM_LEGACY_IRQ
  	taskqueue_unblock(adapter->tq); // XXX do we need this ?
  #endif /* !EM_LEGCY_IRQ */
  
  	EM_CORE_UNLOCK(adapter);
  
  	return (ifp->if_drv_flags & IFF_DRV_RUNNING ? 0 : 1);
  }
  
  
  static void
  lem_netmap_intr(struct netmap_adapter *na, int onoff)
  {
  	struct ifnet *ifp = na->ifp;
  	struct adapter *adapter = ifp->if_softc;
  
  	EM_CORE_LOCK(adapter);
  	if (onoff) {
  		lem_enable_intr(adapter);
  	} else {
  		lem_disable_intr(adapter);
  	}
  	EM_CORE_UNLOCK(adapter);
  }
  
  
  /*
   * Reconcile kernel and user view of the transmit ring.
   */
  static int
  lem_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 const lim = kring->nkr_num_slots - 1;
  	u_int const head = kring->rhead;
  	/* generate an interrupt approximately every half ring */
  	u_int report_frequency = kring->nkr_num_slots >> 1;
  
  	/* device-specific */
  	struct adapter *adapter = ifp->if_softc;
  
  	bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
  			BUS_DMASYNC_POSTREAD);
  
  	/*
  	 * First part: process new packets to send.
  	 */
  
  	nm_i = kring->nr_hwcur;
  	if (nm_i != head) {	/* we have new packets to send */
  		nic_i = netmap_idx_k2n(kring, nm_i);
  		while (nm_i != head) {
  			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 e1000_tx_desc *curr = &adapter->tx_desc_base[nic_i];
  			struct em_buffer *txbuf = &adapter->tx_buffer_area[nic_i];
  			int flags = (slot->flags & NS_REPORT ||
  				nic_i == 0 || nic_i == report_frequency) ?
  				E1000_TXD_CMD_RS : 0;
  
  			NM_CHECK_ADDR_LEN(na, addr, len);
  
  			if (slot->flags & NS_BUF_CHANGED) {
  				/* buffer has changed, reload map */
  				curr->buffer_addr = htole64(paddr);
  				netmap_reload_map(na, adapter->txtag, txbuf->map, addr);
  			}
  			slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);
  
  			/* Fill the slot in the NIC ring. */
  			curr->upper.data = 0;
  			curr->lower.data = htole32(adapter->txd_cmd | len |
  				(E1000_TXD_CMD_EOP | flags) );
  			bus_dmamap_sync(adapter->txtag, txbuf->map,
  				BUS_DMASYNC_PREWRITE);
  
  			nm_i = nm_next(nm_i, lim);
  			nic_i = nm_next(nic_i, lim);
  			// XXX might try an early kick
  		}
  		kring->nr_hwcur = head;
  
  		 /* synchronize the NIC ring */
  		bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
  			BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
  
  		/* (re)start the tx unit up to slot nic_i (excluded) */
  		E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), nic_i);
  	}
  
  	/*
  	 * Second part: reclaim buffers for completed transmissions.
  	 */
  	if (ticks != kring->last_reclaim || flags & NAF_FORCE_RECLAIM || nm_kr_txempty(kring)) {
  		kring->last_reclaim = ticks;
  		/* record completed transmissions using TDH */
  		nic_i = E1000_READ_REG(&adapter->hw, E1000_TDH(0));
  		if (nic_i >= kring->nkr_num_slots) { /* XXX can it happen ? */
  			D("TDH wrap %d", nic_i);
  			nic_i -= kring->nkr_num_slots;
  		}
  		adapter->next_tx_to_clean = nic_i;
  		kring->nr_hwtail = nm_prev(netmap_idx_n2k(kring, nic_i), lim);
  	}
  
  	return 0;
  }
  
  
  /*
   * Reconcile kernel and user view of the receive ring.
   */
  static int
  lem_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 = kring->rhead;
  	int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR;
  
  	/* device-specific */
  	struct adapter *adapter = ifp->if_softc;
  
  	if (head > lim)
  		return netmap_ring_reinit(kring);
  
  	/* XXX check sync modes */
  	bus_dmamap_sync(adapter->rxdma.dma_tag, adapter->rxdma.dma_map,
  			BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
  
  	/*
  	 * First part: import newly received packets.
  	 */
  	if (netmap_no_pendintr || force_update) {
  		nic_i = adapter->next_rx_desc_to_check;
  		nm_i = netmap_idx_n2k(kring, nic_i);
  
  		for (n = 0; ; n++) {
  			struct e1000_rx_desc *curr = &adapter->rx_desc_base[nic_i];
  			uint32_t staterr = le32toh(curr->status);
  			int len;
  
  			if ((staterr & E1000_RXD_STAT_DD) == 0)
  				break;
  			len = le16toh(curr->length) - 4; // CRC
  			if (len < 0) {
  				RD(5, "bogus pkt (%d) size %d nic idx %d", n, len, nic_i);
  				len = 0;
  			}
  			ring->slot[nm_i].len = len;
  			ring->slot[nm_i].flags = 0;
  			bus_dmamap_sync(adapter->rxtag,
  				adapter->rx_buffer_area[nic_i].map,
  				BUS_DMASYNC_POSTREAD);
  			nm_i = nm_next(nm_i, lim);
  			nic_i = nm_next(nic_i, lim);
  		}
  		if (n) { /* update the state variables */
  			ND("%d new packets at nic %d nm %d tail %d",
  				n,
  				adapter->next_rx_desc_to_check,
  				netmap_idx_n2k(kring, adapter->next_rx_desc_to_check),
  				kring->nr_hwtail);
  			adapter->next_rx_desc_to_check = nic_i;
  			// if_inc_counter(ifp, IFCOUNTER_IPACKETS, n);
  			kring->nr_hwtail = nm_i;
  		}
  		kring->nr_kflags &= ~NKR_PENDINTR;
  	}
  
  	/*
  	 * Second part: skip past packets that userspace has released.
  	 */
  	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);
  
  			struct e1000_rx_desc *curr = &adapter->rx_desc_base[nic_i];
  			struct em_buffer *rxbuf = &adapter->rx_buffer_area[nic_i];
  
  			if (addr == NETMAP_BUF_BASE(na)) /* bad buf */
  				goto ring_reset;
  
  			if (slot->flags & NS_BUF_CHANGED) {
  				/* buffer has changed, reload map */
  				curr->buffer_addr = htole64(paddr);
  				netmap_reload_map(na, adapter->rxtag, rxbuf->map, addr);
  				slot->flags &= ~NS_BUF_CHANGED;
  			}
  			curr->status = 0;
  			bus_dmamap_sync(adapter->rxtag, rxbuf->map,
  			    BUS_DMASYNC_PREREAD);
  			nm_i = nm_next(nm_i, lim);
  			nic_i = nm_next(nic_i, lim);
  		}
  		kring->nr_hwcur = head;
  		bus_dmamap_sync(adapter->rxdma.dma_tag, adapter->rxdma.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);
  		E1000_WRITE_REG(&adapter->hw, E1000_RDT(0), nic_i);
  	}
  
  	return 0;
  
  ring_reset:
  	return netmap_ring_reinit(kring);
  }
  
  
  static void
  lem_netmap_attach(struct adapter *adapter)
  {
  	struct netmap_adapter na;
  
  	bzero(&na, sizeof(na));
  
  	na.ifp = adapter->ifp;
  	na.na_flags = NAF_BDG_MAYSLEEP;
  	na.num_tx_desc = adapter->num_tx_desc;
  	na.num_rx_desc = adapter->num_rx_desc;
  	na.nm_txsync = lem_netmap_txsync;
  	na.nm_rxsync = lem_netmap_rxsync;
  	na.nm_register = lem_netmap_reg;
  	na.num_tx_rings = na.num_rx_rings = 1;
  	na.nm_intr = lem_netmap_intr;
  	netmap_attach(&na);
  }
  
  /* end of file */
  