// SPDX-License-Identifier: GPL-2.0
/* Shared Memory Communications Direct over ISM devices (SMC-D)
 *
 * Functions for ISM device.
 *
 * Copyright IBM Corp. 2018
 */

#include <linux/if_vlan.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <asm/page.h>

#include "smc.h"
#include "smc_core.h"
#include "smc_ism.h"
#include "smc_pnet.h"
#include "smc_netlink.h"
#include "linux/dibs.h"

struct smcd_dev_list smcd_dev_list = {
        .list = LIST_HEAD_INIT(smcd_dev_list.list),
        .mutex = __MUTEX_INITIALIZER(smcd_dev_list.mutex)
};

static bool smc_ism_v2_capable;
static u8 smc_ism_v2_system_eid[SMC_MAX_EID_LEN];

static void smcd_register_dev(struct dibs_dev *dibs);
static void smcd_unregister_dev(struct dibs_dev *dibs);
static void smcd_handle_event(struct dibs_dev *dibs,
                              const struct dibs_event *event);
static void smcd_handle_irq(struct dibs_dev *dibs, unsigned int dmbno,
                            u16 dmbemask);

static struct dibs_client_ops smc_client_ops = {
        .add_dev = smcd_register_dev,
        .del_dev = smcd_unregister_dev,
        .handle_event = smcd_handle_event,
        .handle_irq = smcd_handle_irq,
};

static struct dibs_client smc_dibs_client = {
        .name = "SMC-D",
        .ops = &smc_client_ops,
};

static void smc_ism_create_system_eid(void)
{
        struct smc_ism_seid *seid =
                (struct smc_ism_seid *)smc_ism_v2_system_eid;
#if IS_ENABLED(CONFIG_S390)
        struct cpuid id;
        u16 ident_tail;
        char tmp[5];

        memcpy(seid->seid_string, "IBM-SYSZ-ISMSEID00000000", 24);
        get_cpu_id(&id);
        ident_tail = (u16)(id.ident & SMC_ISM_IDENT_MASK);
        snprintf(tmp, 5, "%04X", ident_tail);
        memcpy(seid->serial_number, tmp, 4);
        snprintf(tmp, 5, "%04X", id.machine);
        memcpy(seid->type, tmp, 4);
#else
        memset(seid, 0, SMC_MAX_EID_LEN);
#endif
}

/* Test if an ISM communication is possible - same CPC */
int smc_ism_cantalk(struct smcd_gid *peer_gid, unsigned short vlan_id,
                    struct smcd_dev *smcd)
{
        struct dibs_dev *dibs = smcd->dibs;
        uuid_t ism_rgid;

        copy_to_dibsgid(&ism_rgid, peer_gid);
        return dibs->ops->query_remote_gid(dibs, &ism_rgid, vlan_id ? 1 : 0,
                                          vlan_id);
}

void smc_ism_get_system_eid(u8 **eid)
{
        if (!smc_ism_v2_capable)
                *eid = NULL;
        else
                *eid = smc_ism_v2_system_eid;
}

u16 smc_ism_get_chid(struct smcd_dev *smcd)
{
        return smcd->dibs->ops->get_fabric_id(smcd->dibs);
}

/* HW supports ISM V2 and thus System EID is defined */
bool smc_ism_is_v2_capable(void)
{
        return smc_ism_v2_capable;
}

void smc_ism_set_v2_capable(void)
{
        smc_ism_v2_capable = true;
}

/* Set a connection using this DMBE. */
void smc_ism_set_conn(struct smc_connection *conn)
{
        unsigned long flags;

        spin_lock_irqsave(&conn->lgr->smcd->lock, flags);
        conn->lgr->smcd->conn[conn->rmb_desc->sba_idx] = conn;
        spin_unlock_irqrestore(&conn->lgr->smcd->lock, flags);
}

/* Unset a connection using this DMBE. */
void smc_ism_unset_conn(struct smc_connection *conn)
{
        unsigned long flags;

        if (!conn->rmb_desc)
                return;

        spin_lock_irqsave(&conn->lgr->smcd->lock, flags);
        conn->lgr->smcd->conn[conn->rmb_desc->sba_idx] = NULL;
        spin_unlock_irqrestore(&conn->lgr->smcd->lock, flags);
}

/* Register a VLAN identifier with the ISM device. Use a reference count
 * and add a VLAN identifier only when the first DMB using this VLAN is
 * registered.
 */
int smc_ism_get_vlan(struct smcd_dev *smcd, unsigned short vlanid)
{
        struct smc_ism_vlanid *new_vlan, *vlan;
        unsigned long flags;
        int rc = 0;

        if (!vlanid)                    /* No valid vlan id */
                return -EINVAL;
        if (!smcd->dibs->ops->add_vlan_id)
                return -EOPNOTSUPP;

        /* create new vlan entry, in case we need it */
        new_vlan = kzalloc_obj(*new_vlan);
        if (!new_vlan)
                return -ENOMEM;
        new_vlan->vlanid = vlanid;
        refcount_set(&new_vlan->refcnt, 1);

        /* if there is an existing entry, increase count and return */
        spin_lock_irqsave(&smcd->lock, flags);
        list_for_each_entry(vlan, &smcd->vlan, list) {
                if (vlan->vlanid == vlanid) {
                        refcount_inc(&vlan->refcnt);
                        kfree(new_vlan);
                        goto out;
                }
        }

        /* no existing entry found.
         * add new entry to device; might fail, e.g., if HW limit reached
         */
        if (smcd->dibs->ops->add_vlan_id(smcd->dibs, vlanid)) {
                kfree(new_vlan);
                rc = -EIO;
                goto out;
        }
        list_add_tail(&new_vlan->list, &smcd->vlan);
out:
        spin_unlock_irqrestore(&smcd->lock, flags);
        return rc;
}

/* Unregister a VLAN identifier with the ISM device. Use a reference count
 * and remove a VLAN identifier only when the last DMB using this VLAN is
 * unregistered.
 */
int smc_ism_put_vlan(struct smcd_dev *smcd, unsigned short vlanid)
{
        struct smc_ism_vlanid *vlan;
        unsigned long flags;
        bool found = false;
        int rc = 0;

        if (!vlanid)                    /* No valid vlan id */
                return -EINVAL;
        if (!smcd->dibs->ops->del_vlan_id)
                return -EOPNOTSUPP;

        spin_lock_irqsave(&smcd->lock, flags);
        list_for_each_entry(vlan, &smcd->vlan, list) {
                if (vlan->vlanid == vlanid) {
                        if (!refcount_dec_and_test(&vlan->refcnt))
                                goto out;
                        found = true;
                        break;
                }
        }
        if (!found) {
                rc = -ENOENT;
                goto out;               /* VLAN id not in table */
        }

        /* Found and the last reference just gone */
        if (smcd->dibs->ops->del_vlan_id(smcd->dibs, vlanid))
                rc = -EIO;
        list_del(&vlan->list);
        kfree(vlan);
out:
        spin_unlock_irqrestore(&smcd->lock, flags);
        return rc;
}

void smc_ism_unregister_dmb(struct smcd_dev *smcd,
                            struct smc_buf_desc *dmb_desc)
{
        struct dibs_dmb dmb;

        if (!dmb_desc->dma_addr)
                return;

        memset(&dmb, 0, sizeof(dmb));
        dmb.dmb_tok = dmb_desc->token;
        dmb.idx = dmb_desc->sba_idx;
        dmb.cpu_addr = dmb_desc->cpu_addr;
        dmb.dma_addr = dmb_desc->dma_addr;
        dmb.dmb_len = dmb_desc->len;

        smcd->dibs->ops->unregister_dmb(smcd->dibs, &dmb);

        return;
}

int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len,
                         struct smc_buf_desc *dmb_desc)
{
        struct dibs_dev *dibs;
        struct dibs_dmb dmb;
        int rc;

        memset(&dmb, 0, sizeof(dmb));
        dmb.dmb_len = dmb_len;
        dmb.idx = dmb_desc->sba_idx;
        dmb.vlan_id = lgr->vlan_id;
        copy_to_dibsgid(&dmb.rgid, &lgr->peer_gid);

        dibs = lgr->smcd->dibs;
        rc = dibs->ops->register_dmb(dibs, &dmb, &smc_dibs_client);
        if (!rc) {
                dmb_desc->sba_idx = dmb.idx;
                dmb_desc->token = dmb.dmb_tok;
                dmb_desc->cpu_addr = dmb.cpu_addr;
                dmb_desc->dma_addr = dmb.dma_addr;
                dmb_desc->len = dmb.dmb_len;
        }
        return rc;
}

bool smc_ism_support_dmb_nocopy(struct smcd_dev *smcd)
{
        /* for now only loopback-ism supports
         * merging sndbuf with peer DMB to avoid
         * data copies between them.
         */
        return (smcd->dibs->ops->support_mmapped_rdmb &&
                smcd->dibs->ops->support_mmapped_rdmb(smcd->dibs));
}

int smc_ism_attach_dmb(struct smcd_dev *dev, u64 token,
                       struct smc_buf_desc *dmb_desc)
{
        struct dibs_dmb dmb;
        int rc = 0;

        if (!dev->dibs->ops->attach_dmb)
                return -EINVAL;

        memset(&dmb, 0, sizeof(dmb));
        dmb.dmb_tok = token;
        rc = dev->dibs->ops->attach_dmb(dev->dibs, &dmb);
        if (!rc) {
                dmb_desc->sba_idx = dmb.idx;
                dmb_desc->token = dmb.dmb_tok;
                dmb_desc->cpu_addr = dmb.cpu_addr;
                dmb_desc->dma_addr = dmb.dma_addr;
                dmb_desc->len = dmb.dmb_len;
                dmb_desc->is_attached = true;
        }
        return rc;
}

int smc_ism_detach_dmb(struct smcd_dev *dev, u64 token)
{
        if (!dev->dibs->ops->detach_dmb)
                return -EINVAL;

        return dev->dibs->ops->detach_dmb(dev->dibs, token);
}

static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd,
                                  struct sk_buff *skb,
                                  struct netlink_callback *cb)
{
        char smc_pnet[SMC_MAX_PNETID_LEN + 1];
        struct smc_pci_dev smc_pci_dev;
        struct nlattr *port_attrs;
        struct dibs_dev *dibs;
        struct nlattr *attrs;
        int use_cnt = 0;
        void *nlh;

        dibs = smcd->dibs;
        nlh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
                          &smc_gen_nl_family, NLM_F_MULTI,
                          SMC_NETLINK_GET_DEV_SMCD);
        if (!nlh)
                goto errmsg;
        attrs = nla_nest_start(skb, SMC_GEN_DEV_SMCD);
        if (!attrs)
                goto errout;
        use_cnt = atomic_read(&smcd->lgr_cnt);
        if (nla_put_u32(skb, SMC_NLA_DEV_USE_CNT, use_cnt))
                goto errattr;
        if (nla_put_u8(skb, SMC_NLA_DEV_IS_CRIT, use_cnt > 0))
                goto errattr;
        memset(&smc_pci_dev, 0, sizeof(smc_pci_dev));
        smc_set_pci_values(to_pci_dev(dibs->dev.parent), &smc_pci_dev);
        if (nla_put_u32(skb, SMC_NLA_DEV_PCI_FID, smc_pci_dev.pci_fid))
                goto errattr;
        if (nla_put_u16(skb, SMC_NLA_DEV_PCI_CHID, smc_pci_dev.pci_pchid))
                goto errattr;
        if (nla_put_u16(skb, SMC_NLA_DEV_PCI_VENDOR, smc_pci_dev.pci_vendor))
                goto errattr;
        if (nla_put_u16(skb, SMC_NLA_DEV_PCI_DEVICE, smc_pci_dev.pci_device))
                goto errattr;
        if (nla_put_string(skb, SMC_NLA_DEV_PCI_ID, smc_pci_dev.pci_id))
                goto errattr;

        port_attrs = nla_nest_start(skb, SMC_NLA_DEV_PORT);
        if (!port_attrs)
                goto errattr;
        if (nla_put_u8(skb, SMC_NLA_DEV_PORT_PNET_USR, smcd->pnetid_by_user))
                goto errportattr;
        memcpy(smc_pnet, smcd->pnetid, SMC_MAX_PNETID_LEN);
        smc_pnet[SMC_MAX_PNETID_LEN] = 0;
        if (nla_put_string(skb, SMC_NLA_DEV_PORT_PNETID, smc_pnet))
                goto errportattr;

        nla_nest_end(skb, port_attrs);
        nla_nest_end(skb, attrs);
        genlmsg_end(skb, nlh);
        return 0;

errportattr:
        nla_nest_cancel(skb, port_attrs);
errattr:
        nla_nest_cancel(skb, attrs);
errout:
        nlmsg_cancel(skb, nlh);
errmsg:
        return -EMSGSIZE;
}

static void smc_nl_prep_smcd_dev(struct smcd_dev_list *dev_list,
                                 struct sk_buff *skb,
                                 struct netlink_callback *cb)
{
        struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
        int snum = cb_ctx->pos[0];
        struct smcd_dev *smcd;
        int num = 0;

        mutex_lock(&dev_list->mutex);
        list_for_each_entry(smcd, &dev_list->list, list) {
                if (num < snum)
                        goto next;
                if (smc_ism_is_loopback(smcd->dibs))
                        goto next;
                if (smc_nl_handle_smcd_dev(smcd, skb, cb))
                        goto errout;
next:
                num++;
        }
errout:
        mutex_unlock(&dev_list->mutex);
        cb_ctx->pos[0] = num;
}

int smcd_nl_get_device(struct sk_buff *skb, struct netlink_callback *cb)
{
        smc_nl_prep_smcd_dev(&smcd_dev_list, skb, cb);
        return skb->len;
}

struct smc_ism_event_work {
        struct work_struct work;
        struct smcd_dev *smcd;
        struct dibs_event event;
};

#define ISM_EVENT_REQUEST               0x0001
#define ISM_EVENT_RESPONSE              0x0002
#define ISM_EVENT_REQUEST_IR            0x00000001
#define ISM_EVENT_CODE_SHUTDOWN         0x80
#define ISM_EVENT_CODE_TESTLINK         0x83

union smcd_sw_event_info {
        u64     info;
        struct {
                u8              uid[SMC_LGR_ID_SIZE];
                unsigned short  vlan_id;
                u16             code;
        };
};

static void smcd_handle_sw_event(struct smc_ism_event_work *wrk)
{
        struct dibs_dev *dibs = wrk->smcd->dibs;
        union smcd_sw_event_info ev_info;
        struct smcd_gid peer_gid;
        uuid_t ism_rgid;

        copy_to_smcdgid(&peer_gid, &wrk->event.gid);
        ev_info.info = wrk->event.data;
        switch (wrk->event.subtype) {
        case ISM_EVENT_CODE_SHUTDOWN:   /* Peer shut down DMBs */
                smc_smcd_terminate(wrk->smcd, &peer_gid, ev_info.vlan_id);
                break;
        case ISM_EVENT_CODE_TESTLINK:   /* Activity timer */
                if (ev_info.code == ISM_EVENT_REQUEST &&
                    dibs->ops->signal_event) {
                        ev_info.code = ISM_EVENT_RESPONSE;
                        copy_to_dibsgid(&ism_rgid, &peer_gid);
                        dibs->ops->signal_event(dibs, &ism_rgid,
                                               ISM_EVENT_REQUEST_IR,
                                               ISM_EVENT_CODE_TESTLINK,
                                               ev_info.info);
                }
                break;
        }
}

/* worker for SMC-D events */
static void smc_ism_event_work(struct work_struct *work)
{
        struct smc_ism_event_work *wrk =
                container_of(work, struct smc_ism_event_work, work);
        struct smcd_gid smcd_gid;

        copy_to_smcdgid(&smcd_gid, &wrk->event.gid);

        switch (wrk->event.type) {
        case DIBS_DEV_EVENT: /* GID event, token is peer GID */
                smc_smcd_terminate(wrk->smcd, &smcd_gid, VLAN_VID_MASK);
                break;
        case DIBS_BUF_EVENT:
                break;
        case DIBS_SW_EVENT: /* Software defined event */
                smcd_handle_sw_event(wrk);
                break;
        }
        kfree(wrk);
}

static struct smcd_dev *smcd_alloc_dev(const char *name, int max_dmbs)
{
        struct smcd_dev *smcd;

        smcd = kzalloc_obj(*smcd);
        if (!smcd)
                return NULL;
        smcd->conn = kzalloc_objs(struct smc_connection *, max_dmbs);
        if (!smcd->conn)
                goto free_smcd;

        smcd->event_wq = alloc_ordered_workqueue("ism_evt_wq-%s)",
                                                 WQ_MEM_RECLAIM, name);
        if (!smcd->event_wq)
                goto free_conn;

        spin_lock_init(&smcd->lock);
        spin_lock_init(&smcd->lgr_lock);
        INIT_LIST_HEAD(&smcd->vlan);
        INIT_LIST_HEAD(&smcd->lgr_list);
        init_waitqueue_head(&smcd->lgrs_deleted);
        return smcd;

free_conn:
        kfree(smcd->conn);
free_smcd:
        kfree(smcd);
        return NULL;
}

static void smcd_register_dev(struct dibs_dev *dibs)
{
        struct smcd_dev *smcd, *fentry;
        int max_dmbs;

        max_dmbs = dibs->ops->max_dmbs();

        smcd = smcd_alloc_dev(dev_name(&dibs->dev), max_dmbs);
        if (!smcd)
                return;

        smcd->dibs = dibs;
        dibs_set_priv(dibs, &smc_dibs_client, smcd);

        if (smc_pnetid_by_dev_port(dibs->dev.parent, 0, smcd->pnetid))
                smc_pnetid_by_table_smcd(smcd);

        if (smc_ism_is_loopback(dibs) ||
            (dibs->ops->add_vlan_id &&
             !dibs->ops->add_vlan_id(dibs, ISM_RESERVED_VLANID))) {
                smc_ism_set_v2_capable();
        }

        mutex_lock(&smcd_dev_list.mutex);
        /* sort list:
         * - devices without pnetid before devices with pnetid;
         * - loopback-ism always at the very beginning;
         */
        if (!smcd->pnetid[0]) {
                fentry = list_first_entry_or_null(&smcd_dev_list.list,
                                                  struct smcd_dev, list);
                if (fentry && smc_ism_is_loopback(fentry->dibs))
                        list_add(&smcd->list, &fentry->list);
                else
                        list_add(&smcd->list, &smcd_dev_list.list);
        } else {
                list_add_tail(&smcd->list, &smcd_dev_list.list);
        }
        mutex_unlock(&smcd_dev_list.mutex);

        if (smc_pnet_is_pnetid_set(smcd->pnetid))
                pr_warn_ratelimited("smc: adding smcd device %s with pnetid %.16s%s\n",
                                    dev_name(&dibs->dev), smcd->pnetid,
                                    smcd->pnetid_by_user ?
                                        " (user defined)" :
                                        "");
        else
                pr_warn_ratelimited("smc: adding smcd device %s without pnetid\n",
                                    dev_name(&dibs->dev));
        return;
}

static void smcd_unregister_dev(struct dibs_dev *dibs)
{
        struct smcd_dev *smcd = dibs_get_priv(dibs, &smc_dibs_client);

        pr_warn_ratelimited("smc: removing smcd device %s\n",
                            dev_name(&dibs->dev));
        smcd->going_away = 1;
        smc_smcd_terminate_all(smcd);
        mutex_lock(&smcd_dev_list.mutex);
        list_del_init(&smcd->list);
        mutex_unlock(&smcd_dev_list.mutex);
        destroy_workqueue(smcd->event_wq);
        kfree(smcd->conn);
        kfree(smcd);
}

/* SMCD Device event handler. Called from ISM device interrupt handler.
 * Parameters are ism device pointer,
 * - event->type (0 --> DMB, 1 --> GID),
 * - event->code (event code),
 * - event->tok (either DMB token when event type 0, or GID when event type 1)
 * - event->time (time of day)
 * - event->info (debug info).
 *
 * Context:
 * - Function called in IRQ context from ISM device driver event handler.
 */
static void smcd_handle_event(struct dibs_dev *dibs,
                              const struct dibs_event *event)
{
        struct smcd_dev *smcd = dibs_get_priv(dibs, &smc_dibs_client);
        struct smc_ism_event_work *wrk;

        if (smcd->going_away)
                return;
        /* copy event to event work queue, and let it be handled there */
        wrk = kmalloc_obj(*wrk, GFP_ATOMIC);
        if (!wrk)
                return;
        INIT_WORK(&wrk->work, smc_ism_event_work);
        wrk->smcd = smcd;
        wrk->event = *event;
        queue_work(smcd->event_wq, &wrk->work);
}

/* SMCD Device interrupt handler. Called from ISM device interrupt handler.
 * Parameters are the ism device pointer, DMB number, and the DMBE bitmask.
 * Find the connection and schedule the tasklet for this connection.
 *
 * Context:
 * - Function called in IRQ context from ISM device driver IRQ handler.
 */
static void smcd_handle_irq(struct dibs_dev *dibs, unsigned int dmbno,
                            u16 dmbemask)
{
        struct smcd_dev *smcd = dibs_get_priv(dibs, &smc_dibs_client);
        struct smc_connection *conn = NULL;
        unsigned long flags;

        spin_lock_irqsave(&smcd->lock, flags);
        conn = smcd->conn[dmbno];
        if (conn && !conn->killed)
                tasklet_schedule(&conn->rx_tsklet);
        spin_unlock_irqrestore(&smcd->lock, flags);
}

int smc_ism_signal_shutdown(struct smc_link_group *lgr)
{
        int rc = 0;
        union smcd_sw_event_info ev_info;
        uuid_t ism_rgid;

        if (lgr->peer_shutdown)
                return 0;
        if (!lgr->smcd->dibs->ops->signal_event)
                return 0;

        memcpy(ev_info.uid, lgr->id, SMC_LGR_ID_SIZE);
        ev_info.vlan_id = lgr->vlan_id;
        ev_info.code = ISM_EVENT_REQUEST;
        copy_to_dibsgid(&ism_rgid, &lgr->peer_gid);
        rc = lgr->smcd->dibs->ops->signal_event(lgr->smcd->dibs, &ism_rgid,
                                          ISM_EVENT_REQUEST_IR,
                                          ISM_EVENT_CODE_SHUTDOWN,
                                          ev_info.info);
        return rc;
}

int smc_ism_init(void)
{
        int rc = 0;

        smc_ism_v2_capable = false;
        smc_ism_create_system_eid();

        rc = dibs_register_client(&smc_dibs_client);
        return rc;
}

void smc_ism_exit(void)
{
        dibs_unregister_client(&smc_dibs_client);
}