ethernet-rx.c

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/**********************************************************************
 * Author: Cavium Networks
 *
 * Contact: [email protected]
 * This file is part of the OCTEON SDK
 *
 * Copyright (c) 2003-2010 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/cache.h>
#include <linux/cpumask.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/etherdevice.h>
#include <linux/ip.h>
#include <linux/string.h>
#include <linux/prefetch.h>
#include <linux/ratelimit.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <net/dst.h>
#ifdef CONFIG_XFRM
#include <linux/xfrm.h>
#include <net/xfrm.h>
#endif /* CONFIG_XFRM */

#include <linux/atomic.h>

#include <asm/octeon/octeon.h>

#include "ethernet-defines.h"
#include "ethernet-mem.h"
#include "ethernet-rx.h"
#include "octeon-ethernet.h"
#include "ethernet-util.h"

#include <asm/octeon/cvmx-helper.h>
#include <asm/octeon/cvmx-wqe.h>
#include <asm/octeon/cvmx-fau.h>
#include <asm/octeon/cvmx-pow.h>
#include <asm/octeon/cvmx-pip.h>
#include <asm/octeon/cvmx-scratch.h>

#include <asm/octeon/cvmx-gmxx-defs.h>

struct cvm_napi_wrapper {
    struct napi_struct napi;
} ____cacheline_aligned_in_smp;

static struct cvm_napi_wrapper cvm_oct_napi[NR_CPUS] __cacheline_aligned_in_smp;

struct cvm_oct_core_state {
    int baseline_cores;
    /*
     * The number of additional cores that could be processing
     * input packtes.
     */
    atomic_t available_cores;
    cpumask_t cpu_state;
} ____cacheline_aligned_in_smp;

static struct cvm_oct_core_state core_state __cacheline_aligned_in_smp;

static void cvm_oct_enable_napi(void *_)
{
    int cpu = smp_processor_id();
    napi_schedule(&cvm_oct_napi[cpu].napi);
}

static void cvm_oct_enable_one_cpu(void)
{
    int v;
    int cpu;

    /* Check to see if more CPUs are available for receive processing... */
    v = atomic_sub_if_positive(1, &core_state.available_cores);
    if (v < 0)
        return;

    /* ... if a CPU is available, Turn on NAPI polling for that CPU.  */
    for_each_online_cpu(cpu) {
        if (!cpu_test_and_set(cpu, core_state.cpu_state)) {
            v = smp_call_function_single(cpu, cvm_oct_enable_napi,
                             NULL, 0);
            if (v)
                panic("Can't enable NAPI.");
            break;
        }
    }
}

static void cvm_oct_no_more_work(void)
{
    int cpu = smp_processor_id();

    /*
     * CPU zero is special.  It always has the irq enabled when
     * waiting for incoming packets.
     */
    if (cpu == 0) {
        enable_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group);
        return;
    }

    cpu_clear(cpu, core_state.cpu_state);
    atomic_add(1, &core_state.available_cores);
}

static irqreturn_t cvm_oct_do_interrupt(int cpl, void *dev_id)
{
    /* Disable the IRQ and start napi_poll. */
    disable_irq_nosync(OCTEON_IRQ_WORKQ0 + pow_receive_group);
    cvm_oct_enable_napi(NULL);

    return IRQ_HANDLED;
}

static inline int cvm_oct_check_rcv_error(cvmx_wqe_t *work)
{
    if ((work->word2.snoip.err_code == 10) && (work->len <= 64)) {
        /*
         * Ignore length errors on min size packets. Some
         * equipment incorrectly pads packets to 64+4FCS
         * instead of 60+4FCS.  Note these packets still get
         * counted as frame errors.
         */
    } else
        if (USE_10MBPS_PREAMBLE_WORKAROUND
        && ((work->word2.snoip.err_code == 5)
            || (work->word2.snoip.err_code == 7))) {

        /*
         * We received a packet with either an alignment error
         * or a FCS error. This may be signalling that we are
         * running 10Mbps with GMXX_RXX_FRM_CTL[PRE_CHK]
         * off. If this is the case we need to parse the
         * packet to determine if we can remove a non spec
         * preamble and generate a correct packet.
         */
        int interface = cvmx_helper_get_interface_num(work->ipprt);
        int index = cvmx_helper_get_interface_index_num(work->ipprt);
        union cvmx_gmxx_rxx_frm_ctl gmxx_rxx_frm_ctl;
        gmxx_rxx_frm_ctl.u64 =
            cvmx_read_csr(CVMX_GMXX_RXX_FRM_CTL(index, interface));
        if (gmxx_rxx_frm_ctl.s.pre_chk == 0) {

            uint8_t *ptr =
                cvmx_phys_to_ptr(work->packet_ptr.s.addr);
            int i = 0;

            while (i < work->len - 1) {
                if (*ptr != 0x55)
                    break;
                ptr++;
                i++;
            }

            if (*ptr == 0xd5) {
                /*
                  printk_ratelimited("Port %d received 0xd5 preamble\n", work->ipprt);
                 */
                work->packet_ptr.s.addr += i + 1;
                work->len -= i + 5;
            } else if ((*ptr & 0xf) == 0xd) {
                /*
                  printk_ratelimited("Port %d received 0x?d preamble\n", work->ipprt);
                 */
                work->packet_ptr.s.addr += i;
                work->len -= i + 4;
                for (i = 0; i < work->len; i++) {
                    *ptr =
                        ((*ptr & 0xf0) >> 4) |
                        ((*(ptr + 1) & 0xf) << 4);
                    ptr++;
                }
            } else {
                printk_ratelimited("Port %d unknown preamble, packet "
                           "dropped\n",
                           work->ipprt);
                /*
                   cvmx_helper_dump_packet(work);
                 */
                cvm_oct_free_work(work);
                return 1;
            }
        }
    } else {
        printk_ratelimited("Port %d receive error code %d, packet dropped\n",
                   work->ipprt, work->word2.snoip.err_code);
        cvm_oct_free_work(work);
        return 1;
    }

    return 0;
}

static int cvm_oct_napi_poll(struct napi_struct *napi, int budget)
{
    const int   coreid = cvmx_get_core_num();
    uint64_t    old_group_mask;
    uint64_t    old_scratch;
    int     rx_count = 0;
    int     did_work_request = 0;
    int     packet_not_copied;

    /* Prefetch cvm_oct_device since we know we need it soon */
    prefetch(cvm_oct_device);

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

    /* Only allow work for our group (and preserve priorities) */
    old_group_mask = cvmx_read_csr(CVMX_POW_PP_GRP_MSKX(coreid));
    cvmx_write_csr(CVMX_POW_PP_GRP_MSKX(coreid),
               (old_group_mask & ~0xFFFFull) | 1 << pow_receive_group);

    if (USE_ASYNC_IOBDMA) {
        cvmx_pow_work_request_async(CVMX_SCR_SCRATCH, CVMX_POW_NO_WAIT);
        did_work_request = 1;
    }

    while (rx_count < budget) {
        struct sk_buff *skb = NULL;
        struct sk_buff **pskb = NULL;
        int skb_in_hw;
        cvmx_wqe_t *work;

        if (USE_ASYNC_IOBDMA && did_work_request)
            work = cvmx_pow_work_response_async(CVMX_SCR_SCRATCH);
        else
            work = cvmx_pow_work_request_sync(CVMX_POW_NO_WAIT);

        prefetch(work);
        did_work_request = 0;
        if (work == NULL) {
            union cvmx_pow_wq_int wq_int;
            wq_int.u64 = 0;
            wq_int.s.iq_dis = 1 << pow_receive_group;
            wq_int.s.wq_int = 1 << pow_receive_group;
            cvmx_write_csr(CVMX_POW_WQ_INT, wq_int.u64);
            break;
        }
        pskb = (struct sk_buff **)(cvm_oct_get_buffer_ptr(work->packet_ptr) - sizeof(void *));
        prefetch(pskb);

        if (USE_ASYNC_IOBDMA && rx_count < (budget - 1)) {
            cvmx_pow_work_request_async_nocheck(CVMX_SCR_SCRATCH, CVMX_POW_NO_WAIT);
            did_work_request = 1;
        }

        if (rx_count == 0) {
            /*
             * First time through, see if there is enough
             * work waiting to merit waking another
             * CPU.
             */
            union cvmx_pow_wq_int_cntx counts;
            int backlog;
            int cores_in_use = core_state.baseline_cores - atomic_read(&core_state.available_cores);
            counts.u64 = cvmx_read_csr(CVMX_POW_WQ_INT_CNTX(pow_receive_group));
            backlog = counts.s.iq_cnt + counts.s.ds_cnt;
            if (backlog > budget * cores_in_use && napi != NULL)
                cvm_oct_enable_one_cpu();
        }

        skb_in_hw = USE_SKBUFFS_IN_HW && work->word2.s.bufs == 1;
        if (likely(skb_in_hw)) {
            skb = *pskb;
            prefetch(&skb->head);
            prefetch(&skb->len);
        }
        prefetch(cvm_oct_device[work->ipprt]);

        /* Immediately throw away all packets with receive errors */
        if (unlikely(work->word2.snoip.rcv_error)) {
            if (cvm_oct_check_rcv_error(work))
                continue;
        }

        /*
         * We can only use the zero copy path if skbuffs are
         * in the FPA pool and the packet fits in a single
         * buffer.
         */
        if (likely(skb_in_hw)) {
            skb->data = skb->head + work->packet_ptr.s.addr - cvmx_ptr_to_phys(skb->head);
            prefetch(skb->data);
            skb->len = work->len;
            skb_set_tail_pointer(skb, skb->len);
            packet_not_copied = 1;
        } else {
            /*
             * We have to copy the packet. First allocate
             * an skbuff for it.
             */
            skb = dev_alloc_skb(work->len);
            if (!skb) {
                printk_ratelimited("Port %d failed to allocate "
                           "skbuff, packet dropped\n",
                           work->ipprt);
                cvm_oct_free_work(work);
                continue;
            }

            /*
             * Check if we've received a packet that was
             * entirely stored in the work entry.
             */
            if (unlikely(work->word2.s.bufs == 0)) {
                uint8_t *ptr = work->packet_data;

                if (likely(!work->word2.s.not_IP)) {
                    /*
                     * The beginning of the packet
                     * moves for IP packets.
                     */
                    if (work->word2.s.is_v6)
                        ptr += 2;
                    else
                        ptr += 6;
                }
                memcpy(skb_put(skb, work->len), ptr, work->len);
                /* No packet buffers to free */
            } else {
                int segments = work->word2.s.bufs;
                union cvmx_buf_ptr segment_ptr = work->packet_ptr;
                int len = work->len;

                while (segments--) {
                    union cvmx_buf_ptr next_ptr =
                        *(union cvmx_buf_ptr *)cvmx_phys_to_ptr(segment_ptr.s.addr - 8);

            /*
             * Octeon Errata PKI-100: The segment size is
             * wrong. Until it is fixed, calculate the
             * segment size based on the packet pool
             * buffer size. When it is fixed, the
             * following line should be replaced with this
             * one: int segment_size =
             * segment_ptr.s.size;
             */
                    int segment_size = CVMX_FPA_PACKET_POOL_SIZE -
                        (segment_ptr.s.addr - (((segment_ptr.s.addr >> 7) - segment_ptr.s.back) << 7));
                    /*
                     * Don't copy more than what
                     * is left in the packet.
                     */
                    if (segment_size > len)
                        segment_size = len;
                    /* Copy the data into the packet */
                    memcpy(skb_put(skb, segment_size),
                           cvmx_phys_to_ptr(segment_ptr.s.addr),
                           segment_size);
                    len -= segment_size;
                    segment_ptr = next_ptr;
                }
            }
            packet_not_copied = 0;
        }

        if (likely((work->ipprt < TOTAL_NUMBER_OF_PORTS) &&
               cvm_oct_device[work->ipprt])) {
            struct net_device *dev = cvm_oct_device[work->ipprt];
            struct octeon_ethernet *priv = netdev_priv(dev);

            /*
             * Only accept packets for devices that are
             * currently up.
             */
            if (likely(dev->flags & IFF_UP)) {
                skb->protocol = eth_type_trans(skb, dev);
                skb->dev = dev;

                if (unlikely(work->word2.s.not_IP || work->word2.s.IP_exc ||
                    work->word2.s.L4_error || !work->word2.s.tcp_or_udp))
                    skb->ip_summed = CHECKSUM_NONE;
                else
                    skb->ip_summed = CHECKSUM_UNNECESSARY;

                /* Increment RX stats for virtual ports */
                if (work->ipprt >= CVMX_PIP_NUM_INPUT_PORTS) {
#ifdef CONFIG_64BIT
                    atomic64_add(1, (atomic64_t *)&priv->stats.rx_packets);
                    atomic64_add(skb->len, (atomic64_t *)&priv->stats.rx_bytes);
#else
                    atomic_add(1, (atomic_t *)&priv->stats.rx_packets);
                    atomic_add(skb->len, (atomic_t *)&priv->stats.rx_bytes);
#endif
                }
                netif_receive_skb(skb);
                rx_count++;
            } else {
                /* Drop any packet received for a device that isn't up */
                /*
                  printk_ratelimited("%s: Device not up, packet dropped\n",
                       dev->name);
                */
#ifdef CONFIG_64BIT
                atomic64_add(1, (atomic64_t *)&priv->stats.rx_dropped);
#else
                atomic_add(1, (atomic_t *)&priv->stats.rx_dropped);
#endif
                dev_kfree_skb_irq(skb);
            }
        } else {
            /*
             * Drop any packet received for a device that
             * doesn't exist.
             */
            printk_ratelimited("Port %d not controlled by Linux, packet dropped\n",
                   work->ipprt);
            dev_kfree_skb_irq(skb);
        }
        /*
         * Check to see if the skbuff and work share the same
         * packet buffer.
         */
        if (USE_SKBUFFS_IN_HW && likely(packet_not_copied)) {
            /*
             * This buffer needs to be replaced, increment
             * the number of buffers we need to free by
             * one.
             */
            cvmx_fau_atomic_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE,
                          1);

            cvmx_fpa_free(work, CVMX_FPA_WQE_POOL,
                      DONT_WRITEBACK(1));
        } else {
            cvm_oct_free_work(work);
        }
    }
    /* Restore the original POW group mask */
    cvmx_write_csr(CVMX_POW_PP_GRP_MSKX(coreid), old_group_mask);
    if (USE_ASYNC_IOBDMA) {
        /* Restore the scratch area */
        cvmx_scratch_write64(CVMX_SCR_SCRATCH, old_scratch);
    }
    cvm_oct_rx_refill_pool(0);

    if (rx_count < budget && napi != NULL) {
        /* No more work */
        napi_complete(napi);
        cvm_oct_no_more_work();
    }
    return rx_count;
}

#ifdef CONFIG_NET_POLL_CONTROLLER

void cvm_oct_poll_controller(struct net_device *dev)
{
    cvm_oct_napi_poll(NULL, 16);
}
#endif

void cvm_oct_rx_initialize(void)
{
    int i;
    struct net_device *dev_for_napi = NULL;
    union cvmx_pow_wq_int_thrx int_thr;
    union cvmx_pow_wq_int_pc int_pc;

    for (i = 0; i < TOTAL_NUMBER_OF_PORTS; i++) {
        if (cvm_oct_device[i]) {
            dev_for_napi = cvm_oct_device[i];
            break;
        }
    }

    if (NULL == dev_for_napi)
        panic("No net_devices were allocated.");

    if (max_rx_cpus > 1  && max_rx_cpus < num_online_cpus())
        atomic_set(&core_state.available_cores, max_rx_cpus);
    else
        atomic_set(&core_state.available_cores, num_online_cpus());
    core_state.baseline_cores = atomic_read(&core_state.available_cores);

    core_state.cpu_state = CPU_MASK_NONE;
    for_each_possible_cpu(i) {
        netif_napi_add(dev_for_napi, &cvm_oct_napi[i].napi,
                   cvm_oct_napi_poll, rx_napi_weight);
        napi_enable(&cvm_oct_napi[i].napi);
    }
    /* Register an IRQ hander for to receive POW interrupts */
    i = request_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group,
            cvm_oct_do_interrupt, 0, "Ethernet", cvm_oct_device);

    if (i)
        panic("Could not acquire Ethernet IRQ %d\n",
              OCTEON_IRQ_WORKQ0 + pow_receive_group);

    disable_irq_nosync(OCTEON_IRQ_WORKQ0 + pow_receive_group);

    int_thr.u64 = 0;
    int_thr.s.tc_en = 1;
    int_thr.s.tc_thr = 1;
    /* Enable POW interrupt when our port has at least one packet */
    cvmx_write_csr(CVMX_POW_WQ_INT_THRX(pow_receive_group), int_thr.u64);

    int_pc.u64 = 0;
    int_pc.s.pc_thr = 5;
    cvmx_write_csr(CVMX_POW_WQ_INT_PC, int_pc.u64);


    /* Scheduld NAPI now.  This will indirectly enable interrupts. */
    cvm_oct_enable_one_cpu();
}

void cvm_oct_rx_shutdown(void)
{
    int i;
    /* Shutdown all of the NAPIs */
    for_each_possible_cpu(i)
        netif_napi_del(&cvm_oct_napi[i].napi);
}