/*********************************************************************
 * Author: Cavium Networks
 *
 * Contact: support@caviumnetworks.com
 * This file is part of the OCTEON SDK
 *
 * Copyright (c) 2003-2007 Cavium Networks
 *
 * This file is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, Version 2, as
 * published by the Free Software Foundation.
 *
 * This file is distributed in the hope that it will be useful, but
 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
 * NONINFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this file; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 * or visit http://www.gnu.org/licenses/.
 *
 * This file may also be available under a different license from Cavium.
 * Contact Cavium Networks for more information
*********************************************************************/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/etherdevice.h>
#include <linux/ip.h>
#include <linux/string.h>
#include <linux/ethtool.h>
#include <linux/mii.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <net/dst.h>
#ifdef CONFIG_XFRM
#include <linux/xfrm.h>
#include <net/xfrm.h>
#endif /* CONFIG_XFRM */

#include <asm/atomic.h>

#include <asm/octeon/octeon.h>

#include "ethernet-defines.h"
#include "octeon-ethernet.h"
#include "ethernet-tx.h"
#include "ethernet-util.h"

#include "cvmx-wqe.h"
#include "cvmx-fau.h"
#include "cvmx-pko.h"
#include "cvmx-helper.h"

#include "cvmx-gmxx-defs.h"

/*
 * You can define GET_SKBUFF_QOS() to override how the skbuff 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 skb->priority fieid, define
 * GET_SKBUFF_QOS as: #define GET_SKBUFF_QOS(skb) ((skb)->priority)
 */
#ifndef GET_SKBUFF_QOS
#define GET_SKBUFF_QOS(skb) 0
#endif

/**
 * Packet transmit
 *
 * @skb:    Packet to send
 * @dev:    Device info structure
 * Returns Always returns zero
 */
int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
{
        cvmx_pko_command_word0_t pko_command;
        union cvmx_buf_ptr hw_buffer;
        uint64_t old_scratch;
        uint64_t old_scratch2;
        int dropped;
        int qos;
        int queue_it_up;
        struct octeon_ethernet *priv = netdev_priv(dev);
        int32_t skb_to_free;
        int32_t undo;
        int32_t buffers_to_free;
#if REUSE_SKBUFFS_WITHOUT_FREE
        unsigned char *fpa_head;
#endif

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

        /* 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_SKBUFF_QOS(skb);
                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);

                /*
                 * Fetch and increment the number of packets to be
                 * freed.
                 */
                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,
                                               MAX_SKB_TO_FREE);
        }

        /*
         * 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 ((skb->len < 64) && OCTEON_IS_MODEL(OCTEON_CN3XXX)) {
                union cvmx_gmxx_prtx_cfg 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) {
                                int add_bytes = 64 - skb->len;
                                if ((skb_tail_pointer(skb) + add_bytes) <=
                                    skb_end_pointer(skb))
                                        memset(__skb_put(skb, add_bytes), 0,
                                               add_bytes);
                        }
                }
        }

        /* Build the PKO buffer pointer */
        hw_buffer.u64 = 0;
        hw_buffer.s.addr = cvmx_ptr_to_phys(skb->data);
        hw_buffer.s.pool = 0;
        hw_buffer.s.size =
            (unsigned long)skb_end_pointer(skb) - (unsigned long)skb->head;

        /* Build the PKO command */
        pko_command.u64 = 0;
        pko_command.s.n2 = 1;   /* Don't pollute L2 with the outgoing packet */
        pko_command.s.segs = 1;
        pko_command.s.total_bytes = skb->len;
        pko_command.s.size0 = CVMX_FAU_OP_SIZE_32;
        pko_command.s.subone0 = 1;

        pko_command.s.dontfree = 1;
        pko_command.s.reg0 = priv->fau + qos * 4;
        /*
         * See if we can put this skb in the FPA pool. Any strange
         * behavior from the Linux networking stack will most likely
         * be caused by a bug in the following code. If some field is
         * in use by the network stack and get carried over when a
         * buffer is reused, bad thing may happen.  If in doubt and
         * you dont need the absolute best performance, disable the
         * define REUSE_SKBUFFS_WITHOUT_FREE. The reuse of buffers has
         * shown a 25% increase in performance under some loads.
         */
#if REUSE_SKBUFFS_WITHOUT_FREE
        fpa_head = skb->head + 128 - ((unsigned long)skb->head & 0x7f);
        if (unlikely(skb->data < fpa_head)) {
                /*
                 * printk("TX buffer beginning can't meet FPA
                 * alignment constraints\n");
                 */
                goto dont_put_skbuff_in_hw;
        }
        if (unlikely
            ((skb_end_pointer(skb) - fpa_head) < CVMX_FPA_PACKET_POOL_SIZE)) {
                /*
                   printk("TX buffer isn't large enough for the FPA\n");
                 */
                goto dont_put_skbuff_in_hw;
        }
        if (unlikely(skb_shared(skb))) {
                /*
                   printk("TX buffer sharing data with someone else\n");
                 */
                goto dont_put_skbuff_in_hw;
        }
        if (unlikely(skb_cloned(skb))) {
                /*
                   printk("TX buffer has been cloned\n");
                 */
                goto dont_put_skbuff_in_hw;
        }
        if (unlikely(skb_header_cloned(skb))) {
                /*
                   printk("TX buffer header has been cloned\n");
                 */
                goto dont_put_skbuff_in_hw;
        }
        if (unlikely(skb->destructor)) {
                /*
                   printk("TX buffer has a destructor\n");
                 */
                goto dont_put_skbuff_in_hw;
        }
        if (unlikely(skb_shinfo(skb)->nr_frags)) {
                /*
                   printk("TX buffer has fragments\n");
                 */
                goto dont_put_skbuff_in_hw;
        }
        if (unlikely
            (skb->truesize !=
             sizeof(*skb) + skb_end_pointer(skb) - skb->head)) {
                /*
                   printk("TX buffer truesize has been changed\n");
                 */
                goto dont_put_skbuff_in_hw;
        }

        /*
         * We can use this buffer in the FPA.  We don't need the FAU
         * update anymore
         */
        pko_command.s.reg0 = 0;
        pko_command.s.dontfree = 0;

        hw_buffer.s.back = (skb->data - fpa_head) >> 7;
        *(struct sk_buff **)(fpa_head - sizeof(void *)) = skb;

        /*
         * The skbuff will be reused without ever being freed. We must
         * cleanup a bunch of core things.
         */
        dst_release(skb_dst(skb));
        skb_dst_set(skb, NULL);
#ifdef CONFIG_XFRM
        secpath_put(skb->sp);
        skb->sp = NULL;
#endif
        nf_reset(skb);

#ifdef CONFIG_NET_SCHED
        skb->tc_index = 0;
#ifdef CONFIG_NET_CLS_ACT
        skb->tc_verd = 0;
#endif /* CONFIG_NET_CLS_ACT */
#endif /* CONFIG_NET_SCHED */

dont_put_skbuff_in_hw:
#endif /* REUSE_SKBUFFS_WITHOUT_FREE */

        /* Check if we can use the hardware checksumming */
        if (USE_HW_TCPUDP_CHECKSUM && (skb->protocol == htons(ETH_P_IP)) &&
            (ip_hdr(skb)->version == 4) && (ip_hdr(skb)->ihl == 5) &&
            ((ip_hdr(skb)->frag_off == 0) || (ip_hdr(skb)->frag_off == 1 << 14))
            && ((ip_hdr(skb)->protocol == IP_PROTOCOL_TCP)
                || (ip_hdr(skb)->protocol == IP_PROTOCOL_UDP))) {
                /* Use hardware checksum calc */
                pko_command.s.ipoffp1 = sizeof(struct ethhdr) + 1;
        }

        if (USE_ASYNC_IOBDMA) {
                /* Get the number of skbuffs in use by the hardware */
                CVMX_SYNCIOBDMA;
                skb_to_free = cvmx_scratch_read64(CVMX_SCR_SCRATCH);
                buffers_to_free = cvmx_scratch_read64(CVMX_SCR_SCRATCH + 8);
        } else {
                /* Get the number of skbuffs in use by the hardware */
                skb_to_free = cvmx_fau_fetch_and_add32(priv->fau + qos * 4,
                                                       MAX_SKB_TO_FREE);
                buffers_to_free =
                    cvmx_fau_fetch_and_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE, 0);
        }

        /*
         * We try to claim MAX_SKB_TO_FREE buffers.  If there were not
         * that many available, we have to un-claim (undo) any that
         * were in excess.  If skb_to_free is positive we will free
         * that many buffers.
         */
        undo = skb_to_free > 0 ?
                MAX_SKB_TO_FREE : skb_to_free + MAX_SKB_TO_FREE;
        if (undo > 0)
                cvmx_fau_atomic_add32(priv->fau+qos*4, -undo);
        skb_to_free = -skb_to_free > MAX_SKB_TO_FREE ?
                MAX_SKB_TO_FREE : -skb_to_free;

        /*
         * If we're sending faster than the receive can free them then
         * don't do the HW free.
         */
        if ((buffers_to_free < -100) && !pko_command.s.dontfree) {
                pko_command.s.dontfree = 1;
                pko_command.s.reg0 = priv->fau + qos * 4;
        }

        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 (unlikely
            (skb_queue_len(&priv->tx_free_list[qos]) >= MAX_OUT_QUEUE_DEPTH)) {
                /*
                   DEBUGPRINT("%s: Tx dropped. Too many queued\n", dev->name);
                 */
                dropped = 1;
        }
        /* Send the packet to the output queue */
        else if (unlikely
                 (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", dev->name);
                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);
        }

        queue_it_up = 0;
        if (unlikely(dropped)) {
                dev_kfree_skb_any(skb);
                priv->stats.tx_dropped++;
        } else {
                if (USE_SKBUFFS_IN_HW) {
                        /* Put this packet on the queue to be freed later */
                        if (pko_command.s.dontfree)
                                queue_it_up = 1;
                        else
                                cvmx_fau_atomic_add32
                                    (FAU_NUM_PACKET_BUFFERS_TO_FREE, -1);
                } else {
                        /* Put this packet on the queue to be freed later */
                        queue_it_up = 1;
                }
        }

        if (queue_it_up) {
                spin_lock(&priv->tx_free_list[qos].lock);
                __skb_queue_tail(&priv->tx_free_list[qos], skb);
                cvm_oct_free_tx_skbs(priv, skb_to_free, qos, 0);
                spin_unlock(&priv->tx_free_list[qos].lock);
        } else {
                cvm_oct_free_tx_skbs(priv, skb_to_free, qos, 1);
        }

        return 0;
}

/**
 * Packet transmit to the POW
 *
 * @skb:    Packet to send
 * @dev:    Device info structure
 * Returns Always returns zero
 */
int cvm_oct_xmit_pow(struct sk_buff *skb, struct net_device *dev)
{
        struct octeon_ethernet *priv = netdev_priv(dev);
        void *packet_buffer;
        void *copy_location;

        /* Get a work queue entry */
        cvmx_wqe_t *work = cvmx_fpa_alloc(CVMX_FPA_WQE_POOL);
        if (unlikely(work == NULL)) {
                DEBUGPRINT("%s: Failed to allocate a work queue entry\n",
                           dev->name);
                priv->stats.tx_dropped++;
                dev_kfree_skb(skb);
                return 0;
        }

        /* Get a packet buffer */
        packet_buffer = cvmx_fpa_alloc(CVMX_FPA_PACKET_POOL);
        if (unlikely(packet_buffer == NULL)) {
                DEBUGPRINT("%s: Failed to allocate a packet buffer\n",
                           dev->name);
                cvmx_fpa_free(work, CVMX_FPA_WQE_POOL, DONT_WRITEBACK(1));
                priv->stats.tx_dropped++;
                dev_kfree_skb(skb);
                return 0;
        }

        /*
         * Calculate where we need to copy the data to. We need to
         * leave 8 bytes for a next pointer (unused). We also need to
         * include any configure skip. Then we need to align the IP
         * packet src and dest into the same 64bit word. The below
         * calculation may add a little extra, but that doesn't
         * hurt.
         */
        copy_location = packet_buffer + sizeof(uint64_t);
        copy_location += ((CVMX_HELPER_FIRST_MBUFF_SKIP + 7) & 0xfff8) + 6;

        /*
         * We have to copy the packet since whoever processes this
         * packet will free it to a hardware pool. We can't use the
         * trick of counting outstanding packets like in
         * cvm_oct_xmit.
         */
        memcpy(copy_location, skb->data, skb->len);

        /*
         * Fill in some of the work queue fields. We may need to add
         * more if the software at the other end needs them.
         */
        work->hw_chksum = skb->csum;
        work->len = skb->len;
        work->ipprt = priv->port;
        work->qos = priv->port & 0x7;
        work->grp = pow_send_group;
        work->tag_type = CVMX_HELPER_INPUT_TAG_TYPE;
        work->tag = pow_send_group;     /* FIXME */
        /* Default to zero. Sets of zero later are commented out */
        work->word2.u64 = 0;
        work->word2.s.bufs = 1;
        work->packet_ptr.u64 = 0;
        work->packet_ptr.s.addr = cvmx_ptr_to_phys(copy_location);
        work->packet_ptr.s.pool = CVMX_FPA_PACKET_POOL;
        work->packet_ptr.s.size = CVMX_FPA_PACKET_POOL_SIZE;
        work->packet_ptr.s.back = (copy_location - packet_buffer) >> 7;

        if (skb->protocol == htons(ETH_P_IP)) {
                work->word2.s.ip_offset = 14;
#if 0
                work->word2.s.vlan_valid = 0;   /* FIXME */
                work->word2.s.vlan_cfi = 0;     /* FIXME */
                work->word2.s.vlan_id = 0;      /* FIXME */
                work->word2.s.dec_ipcomp = 0;   /* FIXME */
#endif
                work->word2.s.tcp_or_udp =
                    (ip_hdr(skb)->protocol == IP_PROTOCOL_TCP)
                    || (ip_hdr(skb)->protocol == IP_PROTOCOL_UDP);
#if 0
                /* FIXME */
                work->word2.s.dec_ipsec = 0;
                /* We only support IPv4 right now */
                work->word2.s.is_v6 = 0;
                /* Hardware would set to zero */
                work->word2.s.software = 0;
                /* No error, packet is internal */
                work->word2.s.L4_error = 0;
#endif
                work->word2.s.is_frag = !((ip_hdr(skb)->frag_off == 0)
                                          || (ip_hdr(skb)->frag_off ==
                                              1 << 14));
#if 0
                /* Assume Linux is sending a good packet */
                work->word2.s.IP_exc = 0;
#endif
                work->word2.s.is_bcast = (skb->pkt_type == PACKET_BROADCAST);
                work->word2.s.is_mcast = (skb->pkt_type == PACKET_MULTICAST);
#if 0
                /* This is an IP packet */
                work->word2.s.not_IP = 0;
                /* No error, packet is internal */
                work->word2.s.rcv_error = 0;
                /* No error, packet is internal */
                work->word2.s.err_code = 0;
#endif

                /*
                 * When copying the data, include 4 bytes of the
                 * ethernet header to align the same way hardware
                 * does.
                 */
                memcpy(work->packet_data, skb->data + 10,
                       sizeof(work->packet_data));
        } else {
#if 0
                work->word2.snoip.vlan_valid = 0;       /* FIXME */
                work->word2.snoip.vlan_cfi = 0; /* FIXME */
                work->word2.snoip.vlan_id = 0;  /* FIXME */
                work->word2.snoip.software = 0; /* Hardware would set to zero */
#endif
                work->word2.snoip.is_rarp = skb->protocol == htons(ETH_P_RARP);
                work->word2.snoip.is_arp = skb->protocol == htons(ETH_P_ARP);
                work->word2.snoip.is_bcast =
                    (skb->pkt_type == PACKET_BROADCAST);
                work->word2.snoip.is_mcast =
                    (skb->pkt_type == PACKET_MULTICAST);
                work->word2.snoip.not_IP = 1;   /* IP was done up above */
#if 0
                /* No error, packet is internal */
                work->word2.snoip.rcv_error = 0;
                /* No error, packet is internal */
                work->word2.snoip.err_code = 0;
#endif
                memcpy(work->packet_data, skb->data, sizeof(work->packet_data));
        }

        /* Submit the packet to the POW */
        cvmx_pow_work_submit(work, work->tag, work->tag_type, work->qos,
                             work->grp);
        priv->stats.tx_packets++;
        priv->stats.tx_bytes += skb->len;
        dev_kfree_skb(skb);
        return 0;
}

/**
 * Transmit a work queue entry out of the ethernet port. Both
 * the work queue entry and the packet data can optionally be
 * freed. The work will be freed on error as well.
 *
 * @dev:     Device to transmit out.
 * @work_queue_entry:
 *                Work queue entry to send
 * @do_free: True if the work queue entry and packet data should be
 *                freed. If false, neither will be freed.
 * @qos:     Index into the queues for this port to transmit on. This
 *                is used to implement QoS if their are multiple queues per
 *                port. This parameter must be between 0 and the number of
 *                queues per port minus 1. Values outside of this range will
 *                be change to zero.
 *
 * Returns Zero on success, negative on failure.
 */
int cvm_oct_transmit_qos(struct net_device *dev, void *work_queue_entry,
                         int do_free, int qos)
{
        unsigned long flags;
        union cvmx_buf_ptr hw_buffer;
        cvmx_pko_command_word0_t pko_command;
        int dropped;
        struct octeon_ethernet *priv = netdev_priv(dev);
        cvmx_wqe_t *work = work_queue_entry;

        if (!(dev->flags & IFF_UP)) {
                DEBUGPRINT("%s: Device not up\n", dev->name);
                if (do_free)
                        cvm_oct_free_work(work);
                return -1;
        }

        /* 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)) {
                if (qos <= 0)
                        qos = 0;
                else if (qos >= cvmx_pko_get_num_queues(priv->port))
                        qos = 0;
        } else
                qos = 0;

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

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

        /* Build the PKO buffer pointer */
        hw_buffer.u64 = 0;
        hw_buffer.s.addr = work->packet_ptr.s.addr;
        hw_buffer.s.pool = CVMX_FPA_PACKET_POOL;
        hw_buffer.s.size = CVMX_FPA_PACKET_POOL_SIZE;
        hw_buffer.s.back = work->packet_ptr.s.back;

        /* Build the PKO command */
        pko_command.u64 = 0;
        pko_command.s.n2 = 1;   /* Don't pollute L2 with the outgoing packet */
        pko_command.s.dontfree = !do_free;
        pko_command.s.segs = work->word2.s.bufs;
        pko_command.s.total_bytes = work->len;

        /* Check if we can use the hardware checksumming */
        if (unlikely(work->word2.s.not_IP || work->word2.s.IP_exc))
                pko_command.s.ipoffp1 = 0;
        else
                pko_command.s.ipoffp1 = sizeof(struct ethhdr) + 1;

        /* Send the packet to the output queue */
        if (unlikely
            (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", dev->name);
                dropped = -1;
        }
        local_irq_restore(flags);

        if (unlikely(dropped)) {
                if (do_free)
                        cvm_oct_free_work(work);
                priv->stats.tx_dropped++;
        } else if (do_free)
                cvmx_fpa_free(work, CVMX_FPA_WQE_POOL, DONT_WRITEBACK(1));

        return dropped;
}
EXPORT_SYMBOL(cvm_oct_transmit_qos);

/**
 * This function frees all skb that are currenty queued for TX.
 *
 * @dev:    Device being shutdown
 */
void cvm_oct_tx_shutdown(struct net_device *dev)
{
        struct octeon_ethernet *priv = netdev_priv(dev);
        unsigned long flags;
        int qos;

        for (qos = 0; qos < 16; qos++) {
                spin_lock_irqsave(&priv->tx_free_list[qos].lock, flags);
                while (skb_queue_len(&priv->tx_free_list[qos]))
                        dev_kfree_skb_any(__skb_dequeue
                                          (&priv->tx_free_list[qos]));
                spin_unlock_irqrestore(&priv->tx_free_list[qos].lock, flags);
        }
}