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sys/dev/ixgbe/ixgbe_netmap.c

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/******************************************************************************
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/*$FreeBSD$*/
/*
* 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.
*/
/*
* $FreeBSD$
*
* netmap support for: ixgbe
*
* This file is meant to be a reference on how to implement
* 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.
*/
#ifdef DEV_NETMAP
/*
* Some drivers may need the following headers. Others
* already include them by default
#include <vm/vm.h>
#include <vm/pmap.h>
*/
#include "ixgbe.h"
/*
* device-specific sysctl variables:
*
* ix_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.
*
* ix_rx_miss, ix_rx_miss_bufs:
* count packets that might be missed due to lost interrupts.
*/
SYSCTL_DECL(_dev_netmap);
static int ix_rx_miss, ix_rx_miss_bufs;
int ix_crcstrip;
SYSCTL_INT(_dev_netmap, OID_AUTO, ix_crcstrip,
CTLFLAG_RW, &ix_crcstrip, 0, "strip CRC on rx frames");
SYSCTL_INT(_dev_netmap, OID_AUTO, ix_rx_miss,
CTLFLAG_RW, &ix_rx_miss, 0, "potentially missed rx intr");
SYSCTL_INT(_dev_netmap, OID_AUTO, ix_rx_miss_bufs,
CTLFLAG_RW, &ix_rx_miss_bufs, 0, "potentially missed rx intr bufs");
static void
set_crcstrip(struct ixgbe_hw *hw, int onoff)
{
/* crc stripping is set in two places:
* IXGBE_HLREG0 (modified on init_locked and hw reset)
* IXGBE_RDRXCTL (set by the original driver in
* ixgbe_setup_hw_rsc() called in init_locked.
* We disable the setting when netmap is compiled in).
* We update the values here, but also in ixgbe.c because
* init_locked sometimes is called outside our control.
*/
uint32_t hl, rxc;
hl = IXGBE_READ_REG(hw, IXGBE_HLREG0);
rxc = IXGBE_READ_REG(hw, IXGBE_RDRXCTL);
if (netmap_verbose)
D("%s read HLREG 0x%x rxc 0x%x",
onoff ? "enter" : "exit", hl, rxc);
/* hw requirements ... */
rxc &= ~IXGBE_RDRXCTL_RSCFRSTSIZE;
rxc |= IXGBE_RDRXCTL_RSCACKC;
if (onoff && !ix_crcstrip) {
/* keep the crc. Fast rx */
hl &= ~IXGBE_HLREG0_RXCRCSTRP;
rxc &= ~IXGBE_RDRXCTL_CRCSTRIP;
} else {
/* reset default mode */
hl |= IXGBE_HLREG0_RXCRCSTRP;
rxc |= IXGBE_RDRXCTL_CRCSTRIP;
}
if (netmap_verbose)
D("%s write HLREG 0x%x rxc 0x%x",
onoff ? "enter" : "exit", hl, rxc);
IXGBE_WRITE_REG(hw, IXGBE_HLREG0, hl);
IXGBE_WRITE_REG(hw, IXGBE_RDRXCTL, rxc);
}
/*
* Register/unregister. We are already under netmap lock.
* Only called on the first register or the last unregister.
*/
static int
ixgbe_netmap_reg(struct netmap_adapter *na, int onoff)
{
struct ifnet *ifp = na->ifp;
struct adapter *adapter = ifp->if_softc;
IXGBE_CORE_LOCK(adapter);
adapter->stop_locked(adapter);
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);
}
adapter->init_locked(adapter); /* also enables intr */
set_crcstrip(&adapter->hw, onoff); // XXX why twice ?
IXGBE_CORE_UNLOCK(adapter);
return (ifp->if_drv_flags & IFF_DRV_RUNNING ? 0 : 1);
}
/*
* 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.
*/
static int
ixgbe_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 adapter *adapter = ifp->if_softc;
struct tx_ring *txr = &adapter->tx_rings[kring->ring_id];
int reclaim_tx;
bus_dmamap_sync(txr->txdma.dma_tag, txr->txdma.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.
* The two numbers differ because upon a *_init() we reset
* the NIC ring but leave the netmap ring unchanged.
* For the transmit ring, we have
*
* nm_i = kring->nr_hwcur
* nic_i = IXGBE_TDT (not tracked in the driver)
* and
* nm_i == (nic_i + kring->nkr_hwofs) % ring_size
*
* In this driver kring->nkr_hwofs >= 0, but for other
* drivers it might be negative as well.
*/
/*
* If we have packets to send (kring->nr_hwcur != kring->rhead)
* 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->tx_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 */
union ixgbe_adv_tx_desc *curr = &txr->tx_base[nic_i];
struct ixgbe_tx_buf *txbuf = &txr->tx_buffers[nic_i];
int flags = (slot->flags & NS_REPORT ||
nic_i == 0 || nic_i == report_frequency) ?
IXGBE_TXD_CMD_RS : 0;
/* prefetch for next round */
__builtin_prefetch(&ring->slot[nm_i + 1]);
__builtin_prefetch(&txr->tx_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->txtag, txbuf->map, addr);
}
slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);
/* Fill the slot in the NIC ring. */
/* Use legacy descriptor, they are faster? */
curr->read.buffer_addr = htole64(paddr);
curr->read.olinfo_status = 0;
curr->read.cmd_type_len = htole32(len | flags |
IXGBE_ADVTXD_DCMD_IFCS | IXGBE_TXD_CMD_EOP);
/* make sure changes to the buffer are synced */
bus_dmamap_sync(txr->txtag, 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->txdma.dma_tag, txr->txdma.dma_map,
BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
/* (re)start the tx unit up to slot nic_i (excluded) */
IXGBE_WRITE_REG(&adapter->hw, txr->tail, nic_i);
}
/*
* Second part: reclaim buffers for completed transmissions.
* Because this is expensive (we read a NIC register etc.)
* we only do it in specific cases (see below).
*/
if (flags & NAF_FORCE_RECLAIM) {
reclaim_tx = 1; /* forced reclaim */
} else if (!nm_kr_txempty(kring)) {
reclaim_tx = 0; /* have buffers, no reclaim */
} else {
/*
* No buffers available. Locate previous slot with
* REPORT_STATUS set.
* If the slot has DD set, we can reclaim space,
* otherwise wait for the next interrupt.
* This enables interrupt moderation on the tx
* side though it might reduce throughput.
*/
struct ixgbe_legacy_tx_desc *txd =
(struct ixgbe_legacy_tx_desc *)txr->tx_base;
nic_i = txr->next_to_clean + report_frequency;
if (nic_i > lim)
nic_i -= lim + 1;
// round to the closest with dd set
nic_i = (nic_i < kring->nkr_num_slots / 4 ||
nic_i >= kring->nkr_num_slots*3/4) ?
0 : report_frequency;
reclaim_tx = txd[nic_i].upper.fields.status & IXGBE_TXD_STAT_DD; // XXX cpu_to_le32 ?
}
if (reclaim_tx) {
/*
* Record completed transmissions.
* We (re)use the driver's txr->next_to_clean to keep
* track of the most recently completed transmission.
*
* The datasheet discourages the use of TDH to find
* out the number of sent packets, but we only set
* REPORT_STATUS in a few slots so TDH is the only
* good way.
*/
nic_i = IXGBE_READ_REG(&adapter->hw, IXGBE_TDH(kring->ring_id));
if (nic_i >= kring->nkr_num_slots) { /* XXX can it happen ? */
D("TDH wrap %d", nic_i);
nic_i -= kring->nkr_num_slots;
}
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);
}
}
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.
*/
static int
ixgbe_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;
struct rx_ring *rxr = &adapter->rx_rings[kring->ring_id];
if (head > lim)
return netmap_ring_reinit(kring);
/* XXX check sync modes */
bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.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_to_check;
* nm_i = kring->nr_hwtail (previous)
* and
* nm_i == (nic_i + kring->nkr_hwofs) % ring_size
*
* rxr->next_to_check is set to 0 on a ring reinit
*/
if (netmap_no_pendintr || force_update) {
int crclen = (ix_crcstrip) ? 0 : 4;
uint16_t slot_flags = kring->nkr_slot_flags;
nic_i = rxr->next_to_check; // or also k2n(kring->nr_hwtail)
nm_i = netmap_idx_n2k(kring, nic_i);
for (n = 0; ; n++) {
union ixgbe_adv_rx_desc *curr = &rxr->rx_base[nic_i];
uint32_t staterr = le32toh(curr->wb.upper.status_error);
if ((staterr & IXGBE_RXD_STAT_DD) == 0)
break;
ring->slot[nm_i].len = le16toh(curr->wb.upper.length) - crclen;
ring->slot[nm_i].flags = slot_flags;
bus_dmamap_sync(rxr->ptag,
rxr->rx_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 */
ix_rx_miss ++;
ix_rx_miss_bufs += n;
}
rxr->next_to_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 kring->rhead 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 ixgbe_adv_rx_desc *curr = &rxr->rx_base[nic_i];
struct ixgbe_rx_buf *rxbuf = &rxr->rx_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->wb.upper.status_error = 0;
curr->read.pkt_addr = htole64(paddr);
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->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 nic_i back by one unit
*/
nic_i = nm_prev(nic_i, lim);
IXGBE_WRITE_REG(&adapter->hw, rxr->tail, nic_i);
}
return 0;
ring_reset:
return netmap_ring_reinit(kring);
}
/*
* The attach routine, called near the end of ixgbe_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.
*/
void
ixgbe_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 = ixgbe_netmap_txsync;
na.nm_rxsync = ixgbe_netmap_rxsync;
na.nm_register = ixgbe_netmap_reg;
na.num_tx_rings = na.num_rx_rings = adapter->num_queues;
netmap_attach(&na);
}
#endif /* DEV_NETMAP */
/* end of file */