// SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause

/* Authors: Bernard Metzler <bmt@zurich.ibm.com> */
/* Copyright (c) 2008-2019, IBM Corporation */

#include <linux/init.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <net/net_namespace.h>
#include <linux/rtnetlink.h>
#include <linux/if_arp.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>

#include <net/addrconf.h>
#include <rdma/ib_verbs.h>
#include <rdma/ib_user_verbs.h>
#include <rdma/rdma_netlink.h>
#include <linux/kthread.h>

#include "siw.h"
#include "siw_verbs.h"

MODULE_AUTHOR("Bernard Metzler");
MODULE_DESCRIPTION("Software iWARP Driver");
MODULE_LICENSE("Dual BSD/GPL");

/* transmit from user buffer, if possible */
const bool zcopy_tx = true;

/* Restrict usage of GSO, if hardware peer iwarp is unable to process
 * large packets. try_gso = true lets siw try to use local GSO,
 * if peer agrees.  Not using GSO severly limits siw maximum tx bandwidth.
 */
const bool try_gso;

/* Attach siw also with loopback devices */
const bool loopback_enabled = true;

/* We try to negotiate CRC on, if true */
const bool mpa_crc_required;

/* MPA CRC on/off enforced */
const bool mpa_crc_strict;

/* Control TCP_NODELAY socket option */
const bool siw_tcp_nagle;

/* Select MPA version to be used during connection setup */
u_char mpa_version = MPA_REVISION_2;

/* Selects MPA P2P mode (additional handshake during connection
 * setup, if true.
 */
const bool peer_to_peer;

struct task_struct *siw_tx_thread[NR_CPUS];
struct crypto_shash *siw_crypto_shash;

static int siw_device_register(struct siw_device *sdev, const char *name)
{
        struct ib_device *base_dev = &sdev->base_dev;
        static int dev_id = 1;
        int rv;

        sdev->vendor_part_id = dev_id++;

        rv = ib_register_device(base_dev, name, NULL);
        if (rv) {
                pr_warn("siw: device registration error %d\n", rv);
                return rv;
        }

        siw_dbg(base_dev, "HWaddr=%pM\n", sdev->netdev->dev_addr);

        return 0;
}

static void siw_device_cleanup(struct ib_device *base_dev)
{
        struct siw_device *sdev = to_siw_dev(base_dev);

        xa_destroy(&sdev->qp_xa);
        xa_destroy(&sdev->mem_xa);
}

static int siw_create_tx_threads(void)
{
        int cpu, assigned = 0;

        for_each_online_cpu(cpu) {
                /* Skip HT cores */
                if (cpu % cpumask_weight(topology_sibling_cpumask(cpu)))
                        continue;

                siw_tx_thread[cpu] =
                        kthread_create(siw_run_sq, (unsigned long *)(long)cpu,
                                       "siw_tx/%d", cpu);
                if (IS_ERR(siw_tx_thread[cpu])) {
                        siw_tx_thread[cpu] = NULL;
                        continue;
                }
                kthread_bind(siw_tx_thread[cpu], cpu);

                wake_up_process(siw_tx_thread[cpu]);
                assigned++;
        }
        return assigned;
}

static int siw_dev_qualified(struct net_device *netdev)
{
        /*
         * Additional hardware support can be added here
         * (e.g. ARPHRD_FDDI, ARPHRD_ATM, ...) - see
         * <linux/if_arp.h> for type identifiers.
         */
        if (netdev->type == ARPHRD_ETHER || netdev->type == ARPHRD_IEEE802 ||
            (netdev->type == ARPHRD_LOOPBACK && loopback_enabled))
                return 1;

        return 0;
}

static DEFINE_PER_CPU(atomic_t, siw_use_cnt);

static struct {
        struct cpumask **tx_valid_cpus;
        int num_nodes;
} siw_cpu_info;

static int siw_init_cpulist(void)
{
        int i, num_nodes = nr_node_ids;

        memset(siw_tx_thread, 0, sizeof(siw_tx_thread));

        siw_cpu_info.num_nodes = num_nodes;

        siw_cpu_info.tx_valid_cpus =
                kcalloc(num_nodes, sizeof(struct cpumask *), GFP_KERNEL);
        if (!siw_cpu_info.tx_valid_cpus) {
                siw_cpu_info.num_nodes = 0;
                return -ENOMEM;
        }
        for (i = 0; i < siw_cpu_info.num_nodes; i++) {
                siw_cpu_info.tx_valid_cpus[i] =
                        kzalloc(sizeof(struct cpumask), GFP_KERNEL);
                if (!siw_cpu_info.tx_valid_cpus[i])
                        goto out_err;

                cpumask_clear(siw_cpu_info.tx_valid_cpus[i]);
        }
        for_each_possible_cpu(i)
                cpumask_set_cpu(i, siw_cpu_info.tx_valid_cpus[cpu_to_node(i)]);

        return 0;

out_err:
        siw_cpu_info.num_nodes = 0;
        while (--i >= 0)
                kfree(siw_cpu_info.tx_valid_cpus[i]);
        kfree(siw_cpu_info.tx_valid_cpus);
        siw_cpu_info.tx_valid_cpus = NULL;

        return -ENOMEM;
}

static void siw_destroy_cpulist(void)
{
        int i = 0;

        while (i < siw_cpu_info.num_nodes)
                kfree(siw_cpu_info.tx_valid_cpus[i++]);

        kfree(siw_cpu_info.tx_valid_cpus);
}

/*
 * Choose CPU with least number of active QP's from NUMA node of
 * TX interface.
 */
int siw_get_tx_cpu(struct siw_device *sdev)
{
        const struct cpumask *tx_cpumask;
        int i, num_cpus, cpu, min_use, node = sdev->numa_node, tx_cpu = -1;

        if (node < 0)
                tx_cpumask = cpu_online_mask;
        else
                tx_cpumask = siw_cpu_info.tx_valid_cpus[node];

        num_cpus = cpumask_weight(tx_cpumask);
        if (!num_cpus) {
                /* no CPU on this NUMA node */
                tx_cpumask = cpu_online_mask;
                num_cpus = cpumask_weight(tx_cpumask);
        }
        if (!num_cpus)
                goto out;

        cpu = cpumask_first(tx_cpumask);

        for (i = 0, min_use = SIW_MAX_QP; i < num_cpus;
             i++, cpu = cpumask_next(cpu, tx_cpumask)) {
                int usage;

                /* Skip any cores which have no TX thread */
                if (!siw_tx_thread[cpu])
                        continue;

                usage = atomic_read(&per_cpu(siw_use_cnt, cpu));
                if (usage <= min_use) {
                        tx_cpu = cpu;
                        min_use = usage;
                }
        }
        siw_dbg(&sdev->base_dev,
                "tx cpu %d, node %d, %d qp's\n", tx_cpu, node, min_use);

out:
        if (tx_cpu >= 0)
                atomic_inc(&per_cpu(siw_use_cnt, tx_cpu));
        else
                pr_warn("siw: no tx cpu found\n");

        return tx_cpu;
}

void siw_put_tx_cpu(int cpu)
{
        atomic_dec(&per_cpu(siw_use_cnt, cpu));
}

static struct ib_qp *siw_get_base_qp(struct ib_device *base_dev, int id)
{
        struct siw_qp *qp = siw_qp_id2obj(to_siw_dev(base_dev), id);

        if (qp) {
                /*
                 * siw_qp_id2obj() increments object reference count
                 */
                siw_qp_put(qp);
                return &qp->base_qp;
        }
        return NULL;
}

static const struct ib_device_ops siw_device_ops = {
        .owner = THIS_MODULE,
        .uverbs_abi_ver = SIW_ABI_VERSION,
        .driver_id = RDMA_DRIVER_SIW,

        .alloc_mr = siw_alloc_mr,
        .alloc_pd = siw_alloc_pd,
        .alloc_ucontext = siw_alloc_ucontext,
        .create_cq = siw_create_cq,
        .create_qp = siw_create_qp,
        .create_srq = siw_create_srq,
        .dealloc_driver = siw_device_cleanup,
        .dealloc_pd = siw_dealloc_pd,
        .dealloc_ucontext = siw_dealloc_ucontext,
        .dereg_mr = siw_dereg_mr,
        .destroy_cq = siw_destroy_cq,
        .destroy_qp = siw_destroy_qp,
        .destroy_srq = siw_destroy_srq,
        .get_dma_mr = siw_get_dma_mr,
        .get_port_immutable = siw_get_port_immutable,
        .iw_accept = siw_accept,
        .iw_add_ref = siw_qp_get_ref,
        .iw_connect = siw_connect,
        .iw_create_listen = siw_create_listen,
        .iw_destroy_listen = siw_destroy_listen,
        .iw_get_qp = siw_get_base_qp,
        .iw_reject = siw_reject,
        .iw_rem_ref = siw_qp_put_ref,
        .map_mr_sg = siw_map_mr_sg,
        .mmap = siw_mmap,
        .mmap_free = siw_mmap_free,
        .modify_qp = siw_verbs_modify_qp,
        .modify_srq = siw_modify_srq,
        .poll_cq = siw_poll_cq,
        .post_recv = siw_post_receive,
        .post_send = siw_post_send,
        .post_srq_recv = siw_post_srq_recv,
        .query_device = siw_query_device,
        .query_gid = siw_query_gid,
        .query_port = siw_query_port,
        .query_qp = siw_query_qp,
        .query_srq = siw_query_srq,
        .req_notify_cq = siw_req_notify_cq,
        .reg_user_mr = siw_reg_user_mr,

        INIT_RDMA_OBJ_SIZE(ib_cq, siw_cq, base_cq),
        INIT_RDMA_OBJ_SIZE(ib_pd, siw_pd, base_pd),
        INIT_RDMA_OBJ_SIZE(ib_qp, siw_qp, base_qp),
        INIT_RDMA_OBJ_SIZE(ib_srq, siw_srq, base_srq),
        INIT_RDMA_OBJ_SIZE(ib_ucontext, siw_ucontext, base_ucontext),
};

static struct siw_device *siw_device_create(struct net_device *netdev)
{
        struct siw_device *sdev = NULL;
        struct ib_device *base_dev;
        int rv;

        sdev = ib_alloc_device(siw_device, base_dev);
        if (!sdev)
                return NULL;

        base_dev = &sdev->base_dev;

        sdev->netdev = netdev;

        if (netdev->type != ARPHRD_LOOPBACK) {
                addrconf_addr_eui48((unsigned char *)&base_dev->node_guid,
                                    netdev->dev_addr);
        } else {
                /*
                 * The loopback device does not have a HW address,
                 * but connection mangagement lib expects gid != 0
                 */
                size_t len = min_t(size_t, strlen(base_dev->name), 6);
                char addr[6] = { };

                memcpy(addr, base_dev->name, len);
                addrconf_addr_eui48((unsigned char *)&base_dev->node_guid,
                                    addr);
        }

        base_dev->uverbs_cmd_mask |= BIT_ULL(IB_USER_VERBS_CMD_POST_SEND);

        base_dev->node_type = RDMA_NODE_RNIC;
        memcpy(base_dev->node_desc, SIW_NODE_DESC_COMMON,
               sizeof(SIW_NODE_DESC_COMMON));

        /*
         * Current model (one-to-one device association):
         * One Softiwarp device per net_device or, equivalently,
         * per physical port.
         */
        base_dev->phys_port_cnt = 1;
        base_dev->num_comp_vectors = num_possible_cpus();

        xa_init_flags(&sdev->qp_xa, XA_FLAGS_ALLOC1);
        xa_init_flags(&sdev->mem_xa, XA_FLAGS_ALLOC1);

        ib_set_device_ops(base_dev, &siw_device_ops);
        rv = ib_device_set_netdev(base_dev, netdev, 1);
        if (rv)
                goto error;

        memcpy(base_dev->iw_ifname, netdev->name,
               sizeof(base_dev->iw_ifname));

        /* Disable TCP port mapping */
        base_dev->iw_driver_flags = IW_F_NO_PORT_MAP;

        sdev->attrs.max_qp = SIW_MAX_QP;
        sdev->attrs.max_qp_wr = SIW_MAX_QP_WR;
        sdev->attrs.max_ord = SIW_MAX_ORD_QP;
        sdev->attrs.max_ird = SIW_MAX_IRD_QP;
        sdev->attrs.max_sge = SIW_MAX_SGE;
        sdev->attrs.max_sge_rd = SIW_MAX_SGE_RD;
        sdev->attrs.max_cq = SIW_MAX_CQ;
        sdev->attrs.max_cqe = SIW_MAX_CQE;
        sdev->attrs.max_mr = SIW_MAX_MR;
        sdev->attrs.max_pd = SIW_MAX_PD;
        sdev->attrs.max_mw = SIW_MAX_MW;
        sdev->attrs.max_srq = SIW_MAX_SRQ;
        sdev->attrs.max_srq_wr = SIW_MAX_SRQ_WR;
        sdev->attrs.max_srq_sge = SIW_MAX_SGE;

        INIT_LIST_HEAD(&sdev->cep_list);
        INIT_LIST_HEAD(&sdev->qp_list);

        atomic_set(&sdev->num_ctx, 0);
        atomic_set(&sdev->num_srq, 0);
        atomic_set(&sdev->num_qp, 0);
        atomic_set(&sdev->num_cq, 0);
        atomic_set(&sdev->num_mr, 0);
        atomic_set(&sdev->num_pd, 0);

        sdev->numa_node = dev_to_node(&netdev->dev);
        spin_lock_init(&sdev->lock);

        return sdev;
error:
        ib_dealloc_device(base_dev);

        return NULL;
}

/*
 * Network link becomes unavailable. Mark all
 * affected QP's accordingly.
 */
static void siw_netdev_down(struct work_struct *work)
{
        struct siw_device *sdev =
                container_of(work, struct siw_device, netdev_down);

        struct siw_qp_attrs qp_attrs;
        struct list_head *pos, *tmp;

        memset(&qp_attrs, 0, sizeof(qp_attrs));
        qp_attrs.state = SIW_QP_STATE_ERROR;

        list_for_each_safe(pos, tmp, &sdev->qp_list) {
                struct siw_qp *qp = list_entry(pos, struct siw_qp, devq);

                down_write(&qp->state_lock);
                WARN_ON(siw_qp_modify(qp, &qp_attrs, SIW_QP_ATTR_STATE));
                up_write(&qp->state_lock);
        }
        ib_device_put(&sdev->base_dev);
}

static void siw_device_goes_down(struct siw_device *sdev)
{
        if (ib_device_try_get(&sdev->base_dev)) {
                INIT_WORK(&sdev->netdev_down, siw_netdev_down);
                schedule_work(&sdev->netdev_down);
        }
}

static int siw_netdev_event(struct notifier_block *nb, unsigned long event,
                            void *arg)
{
        struct net_device *netdev = netdev_notifier_info_to_dev(arg);
        struct ib_device *base_dev;
        struct siw_device *sdev;

        dev_dbg(&netdev->dev, "siw: event %lu\n", event);

        if (dev_net(netdev) != &init_net)
                return NOTIFY_OK;

        base_dev = ib_device_get_by_netdev(netdev, RDMA_DRIVER_SIW);
        if (!base_dev)
                return NOTIFY_OK;

        sdev = to_siw_dev(base_dev);

        switch (event) {
        case NETDEV_UP:
                sdev->state = IB_PORT_ACTIVE;
                siw_port_event(sdev, 1, IB_EVENT_PORT_ACTIVE);
                break;

        case NETDEV_GOING_DOWN:
                siw_device_goes_down(sdev);
                break;

        case NETDEV_DOWN:
                sdev->state = IB_PORT_DOWN;
                siw_port_event(sdev, 1, IB_EVENT_PORT_ERR);
                break;

        case NETDEV_REGISTER:
                /*
                 * Device registration now handled only by
                 * rdma netlink commands. So it shall be impossible
                 * to end up here with a valid siw device.
                 */
                siw_dbg(base_dev, "unexpected NETDEV_REGISTER event\n");
                break;

        case NETDEV_UNREGISTER:
                ib_unregister_device_queued(&sdev->base_dev);
                break;

        case NETDEV_CHANGEADDR:
                siw_port_event(sdev, 1, IB_EVENT_LID_CHANGE);
                break;
        /*
         * Todo: Below netdev events are currently not handled.
         */
        case NETDEV_CHANGEMTU:
        case NETDEV_CHANGE:
                break;

        default:
                break;
        }
        ib_device_put(&sdev->base_dev);

        return NOTIFY_OK;
}

static struct notifier_block siw_netdev_nb = {
        .notifier_call = siw_netdev_event,
};

static int siw_newlink(const char *basedev_name, struct net_device *netdev)
{
        struct ib_device *base_dev;
        struct siw_device *sdev = NULL;
        int rv = -ENOMEM;

        if (!siw_dev_qualified(netdev))
                return -EINVAL;

        base_dev = ib_device_get_by_netdev(netdev, RDMA_DRIVER_SIW);
        if (base_dev) {
                ib_device_put(base_dev);
                return -EEXIST;
        }
        sdev = siw_device_create(netdev);
        if (sdev) {
                dev_dbg(&netdev->dev, "siw: new device\n");

                if (netif_running(netdev) && netif_carrier_ok(netdev))
                        sdev->state = IB_PORT_ACTIVE;
                else
                        sdev->state = IB_PORT_DOWN;

                rv = siw_device_register(sdev, basedev_name);
                if (rv)
                        ib_dealloc_device(&sdev->base_dev);
        }
        return rv;
}

static struct rdma_link_ops siw_link_ops = {
        .type = "siw",
        .newlink = siw_newlink,
};

/*
 * siw_init_module - Initialize Softiwarp module and register with netdev
 *                   subsystem.
 */
static __init int siw_init_module(void)
{
        int rv;
        int nr_cpu;

        if (SENDPAGE_THRESH < SIW_MAX_INLINE) {
                pr_info("siw: sendpage threshold too small: %u\n",
                        (int)SENDPAGE_THRESH);
                rv = -EINVAL;
                goto out_error;
        }
        rv = siw_init_cpulist();
        if (rv)
                goto out_error;

        rv = siw_cm_init();
        if (rv)
                goto out_error;

        if (!siw_create_tx_threads()) {
                pr_info("siw: Could not start any TX thread\n");
                rv = -ENOMEM;
                goto out_error;
        }
        /*
         * Locate CRC32 algorithm. If unsuccessful, fail
         * loading siw only, if CRC is required.
         */
        siw_crypto_shash = crypto_alloc_shash("crc32c", 0, 0);
        if (IS_ERR(siw_crypto_shash)) {
                pr_info("siw: Loading CRC32c failed: %ld\n",
                        PTR_ERR(siw_crypto_shash));
                siw_crypto_shash = NULL;
                if (mpa_crc_required) {
                        rv = -EOPNOTSUPP;
                        goto out_error;
                }
        }
        rv = register_netdevice_notifier(&siw_netdev_nb);
        if (rv)
                goto out_error;

        rdma_link_register(&siw_link_ops);

        pr_info("SoftiWARP attached\n");
        return 0;

out_error:
        for (nr_cpu = 0; nr_cpu < nr_cpu_ids; nr_cpu++) {
                if (siw_tx_thread[nr_cpu]) {
                        siw_stop_tx_thread(nr_cpu);
                        siw_tx_thread[nr_cpu] = NULL;
                }
        }
        if (siw_crypto_shash)
                crypto_free_shash(siw_crypto_shash);

        pr_info("SoftIWARP attach failed. Error: %d\n", rv);

        siw_cm_exit();
        siw_destroy_cpulist();

        return rv;
}

static void __exit siw_exit_module(void)
{
        int cpu;

        for_each_possible_cpu(cpu) {
                if (siw_tx_thread[cpu]) {
                        siw_stop_tx_thread(cpu);
                        siw_tx_thread[cpu] = NULL;
                }
        }
        unregister_netdevice_notifier(&siw_netdev_nb);
        rdma_link_unregister(&siw_link_ops);
        ib_unregister_driver(RDMA_DRIVER_SIW);

        siw_cm_exit();

        siw_destroy_cpulist();

        if (siw_crypto_shash)
                crypto_free_shash(siw_crypto_shash);

        pr_info("SoftiWARP detached\n");
}

module_init(siw_init_module);
module_exit(siw_exit_module);

MODULE_ALIAS_RDMA_LINK("siw");