// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:      Sjur Brendeland
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/module.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cfcnfg.h>
#include <net/caif/cfctrl.h>
#include <net/caif/cfmuxl.h>
#include <net/caif/cffrml.h>
#include <net/caif/cfserl.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/caif_dev.h>

#define container_obj(layr) container_of(layr, struct cfcnfg, layer)

/* Information about CAIF physical interfaces held by Config Module in order
 * to manage physical interfaces
 */
struct cfcnfg_phyinfo {
        struct list_head node;
        bool up;

        /* Pointer to the layer below the MUX (framing layer) */
        struct cflayer *frm_layer;
        /* Pointer to the lowest actual physical layer */
        struct cflayer *phy_layer;
        /* Unique identifier of the physical interface */
        unsigned int id;
        /* Preference of the physical in interface */
        enum cfcnfg_phy_preference pref;

        /* Information about the physical device */
        struct dev_info dev_info;

        /* Interface index */
        int ifindex;

        /* Protocol head room added for CAIF link layer */
        int head_room;

        /* Use Start of frame checksum */
        bool use_fcs;
};

struct cfcnfg {
        struct cflayer layer;
        struct cflayer *ctrl;
        struct cflayer *mux;
        struct list_head phys;
        struct mutex lock;
};

static void cfcnfg_linkup_rsp(struct cflayer *layer, u8 channel_id,
                              enum cfctrl_srv serv, u8 phyid,
                              struct cflayer *adapt_layer);
static void cfcnfg_linkdestroy_rsp(struct cflayer *layer, u8 channel_id);
static void cfcnfg_reject_rsp(struct cflayer *layer, u8 channel_id,
                              struct cflayer *adapt_layer);
static void cfctrl_resp_func(void);
static void cfctrl_enum_resp(void);

struct cfcnfg *cfcnfg_create(void)
{
        struct cfcnfg *this;
        struct cfctrl_rsp *resp;

        might_sleep();

        /* Initiate this layer */
        this = kzalloc_obj(struct cfcnfg, GFP_ATOMIC);
        if (!this)
                return NULL;
        this->mux = cfmuxl_create();
        if (!this->mux)
                goto out_of_mem;
        this->ctrl = cfctrl_create();
        if (!this->ctrl)
                goto out_of_mem;
        /* Initiate response functions */
        resp = cfctrl_get_respfuncs(this->ctrl);
        resp->enum_rsp = cfctrl_enum_resp;
        resp->linkerror_ind = cfctrl_resp_func;
        resp->linkdestroy_rsp = cfcnfg_linkdestroy_rsp;
        resp->sleep_rsp = cfctrl_resp_func;
        resp->wake_rsp = cfctrl_resp_func;
        resp->restart_rsp = cfctrl_resp_func;
        resp->radioset_rsp = cfctrl_resp_func;
        resp->linksetup_rsp = cfcnfg_linkup_rsp;
        resp->reject_rsp = cfcnfg_reject_rsp;
        INIT_LIST_HEAD(&this->phys);

        cfmuxl_set_uplayer(this->mux, this->ctrl, 0);
        layer_set_dn(this->ctrl, this->mux);
        layer_set_up(this->ctrl, this);
        mutex_init(&this->lock);

        return this;
out_of_mem:
        synchronize_rcu();

        kfree(this->mux);
        kfree(this->ctrl);
        kfree(this);
        return NULL;
}

void cfcnfg_remove(struct cfcnfg *cfg)
{
        might_sleep();
        if (cfg) {
                synchronize_rcu();

                kfree(cfg->mux);
                cfctrl_remove(cfg->ctrl);
                kfree(cfg);
        }
}

static void cfctrl_resp_func(void)
{
}

static struct cfcnfg_phyinfo *cfcnfg_get_phyinfo_rcu(struct cfcnfg *cnfg,
                                                     u8 phyid)
{
        struct cfcnfg_phyinfo *phy;

        list_for_each_entry_rcu(phy, &cnfg->phys, node)
                if (phy->id == phyid)
                        return phy;
        return NULL;
}

static void cfctrl_enum_resp(void)
{
}

static struct dev_info *cfcnfg_get_phyid(struct cfcnfg *cnfg,
                                  enum cfcnfg_phy_preference phy_pref)
{
        /* Try to match with specified preference */
        struct cfcnfg_phyinfo *phy;

        list_for_each_entry_rcu(phy, &cnfg->phys, node) {
                if (phy->up && phy->pref == phy_pref &&
                                phy->frm_layer != NULL)

                        return &phy->dev_info;
        }

        /* Otherwise just return something */
        list_for_each_entry_rcu(phy, &cnfg->phys, node)
                if (phy->up)
                        return &phy->dev_info;

        return NULL;
}

static int cfcnfg_get_id_from_ifi(struct cfcnfg *cnfg, int ifi)
{
        struct cfcnfg_phyinfo *phy;

        list_for_each_entry_rcu(phy, &cnfg->phys, node)
                if (phy->ifindex == ifi && phy->up)
                        return phy->id;
        return -ENODEV;
}

int caif_disconnect_client(struct net *net, struct cflayer *adap_layer)
{
        u8 channel_id;
        struct cfcnfg *cfg = get_cfcnfg(net);

        caif_assert(adap_layer != NULL);
        cfctrl_cancel_req(cfg->ctrl, adap_layer);
        channel_id = adap_layer->id;
        if (channel_id != 0) {
                struct cflayer *servl;
                servl = cfmuxl_remove_uplayer(cfg->mux, channel_id);
                cfctrl_linkdown_req(cfg->ctrl, channel_id, adap_layer);
                if (servl != NULL)
                        layer_set_up(servl, NULL);
        } else
                pr_debug("nothing to disconnect\n");

        /* Do RCU sync before initiating cleanup */
        synchronize_rcu();
        if (adap_layer->ctrlcmd != NULL)
                adap_layer->ctrlcmd(adap_layer, CAIF_CTRLCMD_DEINIT_RSP, 0);
        return 0;

}
EXPORT_SYMBOL(caif_disconnect_client);

static void cfcnfg_linkdestroy_rsp(struct cflayer *layer, u8 channel_id)
{
}

static const int protohead[CFCTRL_SRV_MASK] = {
        [CFCTRL_SRV_VEI] = 4,
        [CFCTRL_SRV_DATAGRAM] = 7,
        [CFCTRL_SRV_UTIL] = 4,
        [CFCTRL_SRV_RFM] = 3,
        [CFCTRL_SRV_DBG] = 3,
};


static int caif_connect_req_to_link_param(struct cfcnfg *cnfg,
                                          struct caif_connect_request *s,
                                          struct cfctrl_link_param *l)
{
        struct dev_info *dev_info;
        enum cfcnfg_phy_preference pref;
        int res;

        memset(l, 0, sizeof(*l));
        /* In caif protocol low value is high priority */
        l->priority = CAIF_PRIO_MAX - s->priority + 1;

        if (s->ifindex != 0) {
                res = cfcnfg_get_id_from_ifi(cnfg, s->ifindex);
                if (res < 0)
                        return res;
                l->phyid = res;
        } else {
                switch (s->link_selector) {
                case CAIF_LINK_HIGH_BANDW:
                        pref = CFPHYPREF_HIGH_BW;
                        break;
                case CAIF_LINK_LOW_LATENCY:
                        pref = CFPHYPREF_LOW_LAT;
                        break;
                default:
                        return -EINVAL;
                }
                dev_info = cfcnfg_get_phyid(cnfg, pref);
                if (dev_info == NULL)
                        return -ENODEV;
                l->phyid = dev_info->id;
        }
        switch (s->protocol) {
        case CAIFPROTO_AT:
                l->linktype = CFCTRL_SRV_VEI;
                l->endpoint = (s->sockaddr.u.at.type >> 2) & 0x3;
                l->chtype = s->sockaddr.u.at.type & 0x3;
                break;
        case CAIFPROTO_DATAGRAM:
                l->linktype = CFCTRL_SRV_DATAGRAM;
                l->chtype = 0x00;
                l->u.datagram.connid = s->sockaddr.u.dgm.connection_id;
                break;
        case CAIFPROTO_DATAGRAM_LOOP:
                l->linktype = CFCTRL_SRV_DATAGRAM;
                l->chtype = 0x03;
                l->endpoint = 0x00;
                l->u.datagram.connid = s->sockaddr.u.dgm.connection_id;
                break;
        case CAIFPROTO_RFM:
                l->linktype = CFCTRL_SRV_RFM;
                l->u.datagram.connid = s->sockaddr.u.rfm.connection_id;
                strscpy(l->u.rfm.volume, s->sockaddr.u.rfm.volume,
                        sizeof(l->u.rfm.volume));
                break;
        case CAIFPROTO_UTIL:
                l->linktype = CFCTRL_SRV_UTIL;
                l->endpoint = 0x00;
                l->chtype = 0x00;
                strscpy(l->u.utility.name, s->sockaddr.u.util.service,
                        sizeof(l->u.utility.name));
                caif_assert(sizeof(l->u.utility.name) > 10);
                l->u.utility.paramlen = s->param.size;
                if (l->u.utility.paramlen > sizeof(l->u.utility.params))
                        l->u.utility.paramlen = sizeof(l->u.utility.params);

                memcpy(l->u.utility.params, s->param.data,
                       l->u.utility.paramlen);

                break;
        case CAIFPROTO_DEBUG:
                l->linktype = CFCTRL_SRV_DBG;
                l->endpoint = s->sockaddr.u.dbg.service;
                l->chtype = s->sockaddr.u.dbg.type;
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

int caif_connect_client(struct net *net, struct caif_connect_request *conn_req,
                        struct cflayer *adap_layer, int *ifindex,
                        int *proto_head, int *proto_tail)
{
        struct cflayer *frml;
        struct cfcnfg_phyinfo *phy;
        int err;
        struct cfctrl_link_param param;
        struct cfcnfg *cfg = get_cfcnfg(net);

        rcu_read_lock();
        err = caif_connect_req_to_link_param(cfg, conn_req, &param);
        if (err)
                goto unlock;

        phy = cfcnfg_get_phyinfo_rcu(cfg, param.phyid);
        if (!phy) {
                err = -ENODEV;
                goto unlock;
        }
        err = -EINVAL;

        if (adap_layer == NULL) {
                pr_err("adap_layer is zero\n");
                goto unlock;
        }
        if (adap_layer->receive == NULL) {
                pr_err("adap_layer->receive is NULL\n");
                goto unlock;
        }
        if (adap_layer->ctrlcmd == NULL) {
                pr_err("adap_layer->ctrlcmd == NULL\n");
                goto unlock;
        }

        err = -ENODEV;
        frml = phy->frm_layer;
        if (frml == NULL) {
                pr_err("Specified PHY type does not exist!\n");
                goto unlock;
        }
        caif_assert(param.phyid == phy->id);
        caif_assert(phy->frm_layer->id ==
                     param.phyid);
        caif_assert(phy->phy_layer->id ==
                     param.phyid);

        *ifindex = phy->ifindex;
        *proto_tail = 2;
        *proto_head = protohead[param.linktype] + phy->head_room;

        rcu_read_unlock();

        /* FIXME: ENUMERATE INITIALLY WHEN ACTIVATING PHYSICAL INTERFACE */
        cfctrl_enum_req(cfg->ctrl, param.phyid);
        return cfctrl_linkup_request(cfg->ctrl, &param, adap_layer);

unlock:
        rcu_read_unlock();
        return err;
}
EXPORT_SYMBOL(caif_connect_client);

static void cfcnfg_reject_rsp(struct cflayer *layer, u8 channel_id,
                              struct cflayer *adapt_layer)
{
        if (adapt_layer != NULL && adapt_layer->ctrlcmd != NULL)
                adapt_layer->ctrlcmd(adapt_layer,
                                     CAIF_CTRLCMD_INIT_FAIL_RSP, 0);
}

static void
cfcnfg_linkup_rsp(struct cflayer *layer, u8 channel_id, enum cfctrl_srv serv,
                  u8 phyid, struct cflayer *adapt_layer)
{
        struct cfcnfg *cnfg = container_obj(layer);
        struct cflayer *servicel = NULL;
        struct cfcnfg_phyinfo *phyinfo;
        struct net_device *netdev;

        if (channel_id == 0) {
                pr_warn("received channel_id zero\n");
                if (adapt_layer != NULL && adapt_layer->ctrlcmd != NULL)
                        adapt_layer->ctrlcmd(adapt_layer,
                                                CAIF_CTRLCMD_INIT_FAIL_RSP, 0);
                return;
        }

        rcu_read_lock();

        if (adapt_layer == NULL) {
                pr_debug("link setup response but no client exist, send linkdown back\n");
                cfctrl_linkdown_req(cnfg->ctrl, channel_id, NULL);
                goto unlock;
        }

        caif_assert(cnfg != NULL);
        caif_assert(phyid != 0);

        phyinfo = cfcnfg_get_phyinfo_rcu(cnfg, phyid);
        if (phyinfo == NULL) {
                pr_err("ERROR: Link Layer Device disappeared while connecting\n");
                goto unlock;
        }

        caif_assert(phyinfo != NULL);
        caif_assert(phyinfo->id == phyid);
        caif_assert(phyinfo->phy_layer != NULL);
        caif_assert(phyinfo->phy_layer->id == phyid);

        adapt_layer->id = channel_id;

        switch (serv) {
        case CFCTRL_SRV_VEI:
                servicel = cfvei_create(channel_id, &phyinfo->dev_info);
                break;
        case CFCTRL_SRV_DATAGRAM:
                servicel = cfdgml_create(channel_id,
                                        &phyinfo->dev_info);
                break;
        case CFCTRL_SRV_RFM:
                netdev = phyinfo->dev_info.dev;
                servicel = cfrfml_create(channel_id, &phyinfo->dev_info,
                                                netdev->mtu);
                break;
        case CFCTRL_SRV_UTIL:
                servicel = cfutill_create(channel_id, &phyinfo->dev_info);
                break;
        case CFCTRL_SRV_VIDEO:
                servicel = cfvidl_create(channel_id, &phyinfo->dev_info);
                break;
        case CFCTRL_SRV_DBG:
                servicel = cfdbgl_create(channel_id, &phyinfo->dev_info);
                break;
        default:
                pr_err("Protocol error. Link setup response - unknown channel type\n");
                goto unlock;
        }
        if (!servicel)
                goto unlock;
        layer_set_dn(servicel, cnfg->mux);
        cfmuxl_set_uplayer(cnfg->mux, servicel, channel_id);
        layer_set_up(servicel, adapt_layer);
        layer_set_dn(adapt_layer, servicel);

        rcu_read_unlock();

        servicel->ctrlcmd(servicel, CAIF_CTRLCMD_INIT_RSP, 0);
        return;
unlock:
        rcu_read_unlock();
}

int
cfcnfg_add_phy_layer(struct cfcnfg *cnfg,
                     struct net_device *dev, struct cflayer *phy_layer,
                     enum cfcnfg_phy_preference pref,
                     struct cflayer *link_support,
                     bool fcs, int head_room)
{
        struct cflayer *frml;
        struct cfcnfg_phyinfo *phyinfo = NULL;
        int i, res = 0;
        u8 phyid;

        mutex_lock(&cnfg->lock);

        /* CAIF protocol allow maximum 6 link-layers */
        for (i = 0; i < 7; i++) {
                phyid = (dev->ifindex + i) & 0x7;
                if (phyid == 0)
                        continue;
                if (cfcnfg_get_phyinfo_rcu(cnfg, phyid) == NULL)
                        goto got_phyid;
        }
        pr_warn("Too many CAIF Link Layers (max 6)\n");
        res = -EEXIST;
        goto out;

got_phyid:
        phyinfo = kzalloc_obj(struct cfcnfg_phyinfo, GFP_ATOMIC);
        if (!phyinfo) {
                res = -ENOMEM;
                goto out;
        }

        phy_layer->id = phyid;
        phyinfo->pref = pref;
        phyinfo->id = phyid;
        phyinfo->dev_info.id = phyid;
        phyinfo->dev_info.dev = dev;
        phyinfo->phy_layer = phy_layer;
        phyinfo->ifindex = dev->ifindex;
        phyinfo->head_room = head_room;
        phyinfo->use_fcs = fcs;

        frml = cffrml_create(phyid, fcs);

        if (!frml) {
                res = -ENOMEM;
                goto out_err;
        }
        phyinfo->frm_layer = frml;
        layer_set_up(frml, cnfg->mux);

        if (link_support != NULL) {
                link_support->id = phyid;
                layer_set_dn(frml, link_support);
                layer_set_up(link_support, frml);
                layer_set_dn(link_support, phy_layer);
                layer_set_up(phy_layer, link_support);
        } else {
                layer_set_dn(frml, phy_layer);
                layer_set_up(phy_layer, frml);
        }

        list_add_rcu(&phyinfo->node, &cnfg->phys);
out:
        mutex_unlock(&cnfg->lock);
        return res;

out_err:
        kfree(phyinfo);
        mutex_unlock(&cnfg->lock);
        return res;
}
EXPORT_SYMBOL(cfcnfg_add_phy_layer);

int cfcnfg_set_phy_state(struct cfcnfg *cnfg, struct cflayer *phy_layer,
                         bool up)
{
        struct cfcnfg_phyinfo *phyinfo;

        rcu_read_lock();
        phyinfo = cfcnfg_get_phyinfo_rcu(cnfg, phy_layer->id);
        if (phyinfo == NULL) {
                rcu_read_unlock();
                return -ENODEV;
        }

        if (phyinfo->up == up) {
                rcu_read_unlock();
                return 0;
        }
        phyinfo->up = up;

        if (up) {
                cffrml_hold(phyinfo->frm_layer);
                cfmuxl_set_dnlayer(cnfg->mux, phyinfo->frm_layer,
                                        phy_layer->id);
        } else {
                cfmuxl_remove_dnlayer(cnfg->mux, phy_layer->id);
                cffrml_put(phyinfo->frm_layer);
        }

        rcu_read_unlock();
        return 0;
}
EXPORT_SYMBOL(cfcnfg_set_phy_state);

int cfcnfg_del_phy_layer(struct cfcnfg *cnfg, struct cflayer *phy_layer)
{
        struct cflayer *frml, *frml_dn;
        u16 phyid;
        struct cfcnfg_phyinfo *phyinfo;

        might_sleep();

        mutex_lock(&cnfg->lock);

        phyid = phy_layer->id;
        phyinfo = cfcnfg_get_phyinfo_rcu(cnfg, phyid);

        if (phyinfo == NULL) {
                mutex_unlock(&cnfg->lock);
                return 0;
        }
        caif_assert(phyid == phyinfo->id);
        caif_assert(phy_layer == phyinfo->phy_layer);
        caif_assert(phy_layer->id == phyid);
        caif_assert(phyinfo->frm_layer->id == phyid);

        list_del_rcu(&phyinfo->node);
        synchronize_rcu();

        /* Fail if reference count is not zero */
        if (cffrml_refcnt_read(phyinfo->frm_layer) != 0) {
                pr_info("Wait for device inuse\n");
                list_add_rcu(&phyinfo->node, &cnfg->phys);
                mutex_unlock(&cnfg->lock);
                return -EAGAIN;
        }

        frml = phyinfo->frm_layer;
        frml_dn = frml->dn;
        cffrml_set_uplayer(frml, NULL);
        cffrml_set_dnlayer(frml, NULL);
        if (phy_layer != frml_dn) {
                layer_set_up(frml_dn, NULL);
                layer_set_dn(frml_dn, NULL);
        }
        layer_set_up(phy_layer, NULL);

        if (phyinfo->phy_layer != frml_dn)
                kfree(frml_dn);

        cffrml_free(frml);
        kfree(phyinfo);
        mutex_unlock(&cnfg->lock);

        return 0;
}
EXPORT_SYMBOL(cfcnfg_del_phy_layer);