cavium/octe/ethernet-tx.c

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#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/sys/mips/cavium/octe/ethernet-tx.c 217244 2011-01-10 22:14:30Z jmallett $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/socket.h>

#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if.h>

#include "wrapper-cvmx-includes.h"
#include "ethernet-headers.h"

/* You can define GET_MBUF_QOS() to override how the mbuf output function
   determines which output queue is used. The default implementation
   always uses the base queue for the port. If, for example, you wanted
   to use the m->priority fieid, define GET_MBUF_QOS as:
   #define GET_MBUF_QOS(m) ((m)->priority) */
#ifndef GET_MBUF_QOS
    #define GET_MBUF_QOS(m) 0
#endif


/**
 * Packet transmit
 *
 * @param m    Packet to send
 * @param dev    Device info structure
 * @return Always returns zero
 */
int cvm_oct_xmit(struct mbuf *m, struct ifnet *ifp)
{
	cvmx_pko_command_word0_t    pko_command;
	cvmx_buf_ptr_t              hw_buffer;
	uint64_t                    old_scratch;
	uint64_t                    old_scratch2;
	int                         dropped;
	int                         qos;
	cvm_oct_private_t          *priv = (cvm_oct_private_t *)ifp->if_softc;
	int32_t in_use;
	int32_t buffers_to_free;
	cvmx_wqe_t *work;

	/* Prefetch the private data structure.
	   It is larger that one cache line */
	CVMX_PREFETCH(priv, 0);

	/* Start off assuming no drop */
	dropped = 0;

	/* The check on CVMX_PKO_QUEUES_PER_PORT_* is designed to completely
	   remove "qos" in the event neither interface supports multiple queues
	   per port */
	if ((CVMX_PKO_QUEUES_PER_PORT_INTERFACE0 > 1) ||
	    (CVMX_PKO_QUEUES_PER_PORT_INTERFACE1 > 1)) {
		qos = GET_MBUF_QOS(m);
		if (qos <= 0)
			qos = 0;
		else if (qos >= cvmx_pko_get_num_queues(priv->port))
			qos = 0;
	} else
		qos = 0;

	if (USE_ASYNC_IOBDMA) {
		/* Save scratch in case userspace is using it */
		CVMX_SYNCIOBDMA;
		old_scratch = cvmx_scratch_read64(CVMX_SCR_SCRATCH);
		old_scratch2 = cvmx_scratch_read64(CVMX_SCR_SCRATCH+8);

		/* Assume we're going to be able t osend this packet. Fetch and increment
		   the number of pending packets for output */
		cvmx_fau_async_fetch_and_add32(CVMX_SCR_SCRATCH+8, FAU_NUM_PACKET_BUFFERS_TO_FREE, 0);
		cvmx_fau_async_fetch_and_add32(CVMX_SCR_SCRATCH, priv->fau+qos*4, 1);
	}

	/* The CN3XXX series of parts has an errata (GMX-401) which causes the
	   GMX block to hang if a collision occurs towards the end of a
	   <68 byte packet. As a workaround for this, we pad packets to be
	   68 bytes whenever we are in half duplex mode. We don't handle
	   the case of having a small packet but no room to add the padding.
	   The kernel should always give us at least a cache line */
	if (__predict_false(m->m_pkthdr.len < 64) && OCTEON_IS_MODEL(OCTEON_CN3XXX)) {
		cvmx_gmxx_prtx_cfg_t gmx_prt_cfg;
		int interface = INTERFACE(priv->port);
		int index = INDEX(priv->port);

		if (interface < 2) {
			/* We only need to pad packet in half duplex mode */
			gmx_prt_cfg.u64 = cvmx_read_csr(CVMX_GMXX_PRTX_CFG(index, interface));
			if (gmx_prt_cfg.s.duplex == 0) {
				static uint8_t pad[64];

				if (!m_append(m, sizeof pad - m->m_pkthdr.len, pad))
					printf("%s: unable to padd small packet.", __func__);
			}
		}
	}

	/*
	 * If the packet is not fragmented.
	 */
	if (m->m_pkthdr.len == m->m_len) {
		/* Build the PKO buffer pointer */
		hw_buffer.u64 = 0;
		hw_buffer.s.addr = cvmx_ptr_to_phys(m->m_data);
		hw_buffer.s.pool = 0;
		hw_buffer.s.size = m->m_len;

		/* Build the PKO command */
		pko_command.u64 = 0;
		pko_command.s.segs = 1;
		pko_command.s.dontfree = 1; /* Do not put this buffer into the FPA.  */

		work = NULL;
	} else {
		struct mbuf *n;
		unsigned segs;
		uint64_t *gp;

		/*
		 * The packet is fragmented, we need to send a list of segments
		 * in memory we borrow from the WQE pool.
		 */
		work = cvmx_fpa_alloc(CVMX_FPA_WQE_POOL);
		gp = (uint64_t *)work;

		segs = 0;
		for (n = m; n != NULL; n = n->m_next) {
			if (segs == CVMX_FPA_WQE_POOL_SIZE / sizeof (uint64_t))
				panic("%s: too many segments in packet; call m_collapse().", __func__);

			/* Build the PKO buffer pointer */
			hw_buffer.u64 = 0;
			hw_buffer.s.i = 1; /* Do not put this buffer into the FPA.  */
			hw_buffer.s.addr = cvmx_ptr_to_phys(n->m_data);
			hw_buffer.s.pool = 0;
			hw_buffer.s.size = n->m_len;

			*gp++ = hw_buffer.u64;
			segs++;
		}

		/* Build the PKO buffer gather list pointer */
		hw_buffer.u64 = 0;
		hw_buffer.s.addr = cvmx_ptr_to_phys(work);
		hw_buffer.s.pool = CVMX_FPA_WQE_POOL;
		hw_buffer.s.size = segs;

		/* Build the PKO command */
		pko_command.u64 = 0;
		pko_command.s.segs = segs;
		pko_command.s.gather = 1;
		pko_command.s.dontfree = 0; /* Put the WQE above back into the FPA.  */
	}

	/* Finish building the PKO command */
	pko_command.s.n2 = 1; /* Don't pollute L2 with the outgoing packet */
	pko_command.s.reg0 = priv->fau+qos*4;
	pko_command.s.total_bytes = m->m_pkthdr.len;
	pko_command.s.size0 = CVMX_FAU_OP_SIZE_32;
	pko_command.s.subone0 = 1;

	/* Check if we can use the hardware checksumming */
	if (USE_HW_TCPUDP_CHECKSUM &&
	    (m->m_pkthdr.csum_flags & (CSUM_TCP | CSUM_UDP)) != 0) {
		/* Use hardware checksum calc */
		pko_command.s.ipoffp1 = ETHER_HDR_LEN + 1;
	}

	/*
	 * XXX
	 * Could use a different free queue (and different FAU address) per
	 * core instead of per QoS, to reduce contention here.
	 */
	IF_LOCK(&priv->tx_free_queue[qos]);
	if (USE_ASYNC_IOBDMA) {
		/* Get the number of mbufs in use by the hardware */
		CVMX_SYNCIOBDMA;
		in_use = cvmx_scratch_read64(CVMX_SCR_SCRATCH);
		buffers_to_free = cvmx_scratch_read64(CVMX_SCR_SCRATCH+8);
	} else {
		/* Get the number of mbufs in use by the hardware */
		in_use = cvmx_fau_fetch_and_add32(priv->fau+qos*4, 1);
		buffers_to_free = cvmx_fau_fetch_and_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE, 0);
	}

	cvmx_pko_send_packet_prepare(priv->port, priv->queue + qos, CVMX_PKO_LOCK_CMD_QUEUE);

	/* Drop this packet if we have too many already queued to the HW */
	if (_IF_QFULL(&priv->tx_free_queue[qos])) {
		dropped = 1;
	}
	/* Send the packet to the output queue */
	else
	if (__predict_false(cvmx_pko_send_packet_finish(priv->port, priv->queue + qos, pko_command, hw_buffer, CVMX_PKO_LOCK_CMD_QUEUE))) {
		DEBUGPRINT("%s: Failed to send the packet\n", if_name(ifp));
		dropped = 1;
	}

	if (USE_ASYNC_IOBDMA) {
		/* Restore the scratch area */
		cvmx_scratch_write64(CVMX_SCR_SCRATCH, old_scratch);
		cvmx_scratch_write64(CVMX_SCR_SCRATCH+8, old_scratch2);
	}

	if (__predict_false(dropped)) {
		m_freem(m);
		cvmx_fau_atomic_add32(priv->fau+qos*4, -1);
		ifp->if_oerrors++;
	} else {
		/* Put this packet on the queue to be freed later */
		_IF_ENQUEUE(&priv->tx_free_queue[qos], m);

		/* Pass it to any BPF listeners.  */
		ETHER_BPF_MTAP(ifp, m);

		ifp->if_opackets++;
		ifp->if_obytes += m->m_pkthdr.len;
	}

	/* Free mbufs not in use by the hardware */
	if (_IF_QLEN(&priv->tx_free_queue[qos]) > in_use) {
		while (_IF_QLEN(&priv->tx_free_queue[qos]) > in_use) {
			_IF_DEQUEUE(&priv->tx_free_queue[qos], m);
			m_freem(m);
		}
	}
	IF_UNLOCK(&priv->tx_free_queue[qos]);

	return dropped;
}


/**
 * This function frees all mbufs that are currenty queued for TX.
 *
 * @param dev    Device being shutdown
 */
void cvm_oct_tx_shutdown(struct ifnet *ifp)
{
	cvm_oct_private_t *priv = (cvm_oct_private_t *)ifp->if_softc;
	int qos;

	for (qos = 0; qos < 16; qos++) {
		IF_DRAIN(&priv->tx_free_queue[qos]);
	}
}