// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/dsa/dsa.c - Hardware switch handling
 * Copyright (c) 2008-2009 Marvell Semiconductor
 * Copyright (c) 2013 Florian Fainelli <florian@openwrt.org>
 */

#include <linux/device.h>
#include <linux/list.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_mdio.h>
#include <linux/of_platform.h>
#include <linux/of_net.h>
#include <linux/netdevice.h>
#include <linux/sysfs.h>
#include <linux/phy_fixed.h>
#include <linux/ptp_classify.h>
#include <linux/etherdevice.h>

#include "dsa_priv.h"

static LIST_HEAD(dsa_tag_drivers_list);
static DEFINE_MUTEX(dsa_tag_drivers_lock);

static struct sk_buff *dsa_slave_notag_xmit(struct sk_buff *skb,
                                            struct net_device *dev)
{
        /* Just return the original SKB */
        return skb;
}

static const struct dsa_device_ops none_ops = {
        .name   = "none",
        .proto  = DSA_TAG_PROTO_NONE,
        .xmit   = dsa_slave_notag_xmit,
        .rcv    = NULL,
};

DSA_TAG_DRIVER(none_ops);

static void dsa_tag_driver_register(struct dsa_tag_driver *dsa_tag_driver,
                                    struct module *owner)
{
        dsa_tag_driver->owner = owner;

        mutex_lock(&dsa_tag_drivers_lock);
        list_add_tail(&dsa_tag_driver->list, &dsa_tag_drivers_list);
        mutex_unlock(&dsa_tag_drivers_lock);
}

void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
                              unsigned int count, struct module *owner)
{
        unsigned int i;

        for (i = 0; i < count; i++)
                dsa_tag_driver_register(dsa_tag_driver_array[i], owner);
}

static void dsa_tag_driver_unregister(struct dsa_tag_driver *dsa_tag_driver)
{
        mutex_lock(&dsa_tag_drivers_lock);
        list_del(&dsa_tag_driver->list);
        mutex_unlock(&dsa_tag_drivers_lock);
}
EXPORT_SYMBOL_GPL(dsa_tag_drivers_register);

void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
                                unsigned int count)
{
        unsigned int i;

        for (i = 0; i < count; i++)
                dsa_tag_driver_unregister(dsa_tag_driver_array[i]);
}
EXPORT_SYMBOL_GPL(dsa_tag_drivers_unregister);

const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops)
{
        return ops->name;
};

const struct dsa_device_ops *dsa_tag_driver_get(int tag_protocol)
{
        struct dsa_tag_driver *dsa_tag_driver;
        const struct dsa_device_ops *ops;
        bool found = false;

        request_module("%s%d", DSA_TAG_DRIVER_ALIAS, tag_protocol);

        mutex_lock(&dsa_tag_drivers_lock);
        list_for_each_entry(dsa_tag_driver, &dsa_tag_drivers_list, list) {
                ops = dsa_tag_driver->ops;
                if (ops->proto == tag_protocol) {
                        found = true;
                        break;
                }
        }

        if (found) {
                if (!try_module_get(dsa_tag_driver->owner))
                        ops = ERR_PTR(-ENOPROTOOPT);
        } else {
                ops = ERR_PTR(-ENOPROTOOPT);
        }

        mutex_unlock(&dsa_tag_drivers_lock);

        return ops;
}

void dsa_tag_driver_put(const struct dsa_device_ops *ops)
{
        struct dsa_tag_driver *dsa_tag_driver;

        mutex_lock(&dsa_tag_drivers_lock);
        list_for_each_entry(dsa_tag_driver, &dsa_tag_drivers_list, list) {
                if (dsa_tag_driver->ops == ops) {
                        module_put(dsa_tag_driver->owner);
                        break;
                }
        }
        mutex_unlock(&dsa_tag_drivers_lock);
}

static int dev_is_class(struct device *dev, void *class)
{
        if (dev->class != NULL && !strcmp(dev->class->name, class))
                return 1;

        return 0;
}

static struct device *dev_find_class(struct device *parent, char *class)
{
        if (dev_is_class(parent, class)) {
                get_device(parent);
                return parent;
        }

        return device_find_child(parent, class, dev_is_class);
}

struct net_device *dsa_dev_to_net_device(struct device *dev)
{
        struct device *d;

        d = dev_find_class(dev, "net");
        if (d != NULL) {
                struct net_device *nd;

                nd = to_net_dev(d);
                dev_hold(nd);
                put_device(d);

                return nd;
        }

        return NULL;
}
EXPORT_SYMBOL_GPL(dsa_dev_to_net_device);

/* Determine if we should defer delivery of skb until we have a rx timestamp.
 *
 * Called from dsa_switch_rcv. For now, this will only work if tagging is
 * enabled on the switch. Normally the MAC driver would retrieve the hardware
 * timestamp when it reads the packet out of the hardware. However in a DSA
 * switch, the DSA driver owning the interface to which the packet is
 * delivered is never notified unless we do so here.
 */
static bool dsa_skb_defer_rx_timestamp(struct dsa_slave_priv *p,
                                       struct sk_buff *skb)
{
        struct dsa_switch *ds = p->dp->ds;
        unsigned int type;

        if (skb_headroom(skb) < ETH_HLEN)
                return false;

        __skb_push(skb, ETH_HLEN);

        type = ptp_classify_raw(skb);

        __skb_pull(skb, ETH_HLEN);

        if (type == PTP_CLASS_NONE)
                return false;

        if (likely(ds->ops->port_rxtstamp))
                return ds->ops->port_rxtstamp(ds, p->dp->index, skb, type);

        return false;
}

static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
                          struct packet_type *pt, struct net_device *unused)
{
        struct dsa_port *cpu_dp = dev->dsa_ptr;
        struct sk_buff *nskb = NULL;
        struct pcpu_sw_netstats *s;
        struct dsa_slave_priv *p;

        if (unlikely(!cpu_dp)) {
                kfree_skb(skb);
                return 0;
        }

        skb = skb_unshare(skb, GFP_ATOMIC);
        if (!skb)
                return 0;

        nskb = cpu_dp->rcv(skb, dev, pt);
        if (!nskb) {
                kfree_skb(skb);
                return 0;
        }

        skb = nskb;
        p = netdev_priv(skb->dev);
        skb_push(skb, ETH_HLEN);
        skb->pkt_type = PACKET_HOST;
        skb->protocol = eth_type_trans(skb, skb->dev);

        s = this_cpu_ptr(p->stats64);
        u64_stats_update_begin(&s->syncp);
        s->rx_packets++;
        s->rx_bytes += skb->len;
        u64_stats_update_end(&s->syncp);

        if (dsa_skb_defer_rx_timestamp(p, skb))
                return 0;

        gro_cells_receive(&p->gcells, skb);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static bool dsa_is_port_initialized(struct dsa_switch *ds, int p)
{
        const struct dsa_port *dp = dsa_to_port(ds, p);

        return dp->type == DSA_PORT_TYPE_USER && dp->slave;
}

int dsa_switch_suspend(struct dsa_switch *ds)
{
        int i, ret = 0;

        /* Suspend slave network devices */
        for (i = 0; i < ds->num_ports; i++) {
                if (!dsa_is_port_initialized(ds, i))
                        continue;

                ret = dsa_slave_suspend(dsa_to_port(ds, i)->slave);
                if (ret)
                        return ret;
        }

        if (ds->ops->suspend)
                ret = ds->ops->suspend(ds);

        return ret;
}
EXPORT_SYMBOL_GPL(dsa_switch_suspend);

int dsa_switch_resume(struct dsa_switch *ds)
{
        int i, ret = 0;

        if (ds->ops->resume)
                ret = ds->ops->resume(ds);

        if (ret)
                return ret;

        /* Resume slave network devices */
        for (i = 0; i < ds->num_ports; i++) {
                if (!dsa_is_port_initialized(ds, i))
                        continue;

                ret = dsa_slave_resume(dsa_to_port(ds, i)->slave);
                if (ret)
                        return ret;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(dsa_switch_resume);
#endif

static struct packet_type dsa_pack_type __read_mostly = {
        .type   = cpu_to_be16(ETH_P_XDSA),
        .func   = dsa_switch_rcv,
};

static struct workqueue_struct *dsa_owq;

bool dsa_schedule_work(struct work_struct *work)
{
        return queue_work(dsa_owq, work);
}

static ATOMIC_NOTIFIER_HEAD(dsa_notif_chain);

int register_dsa_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&dsa_notif_chain, nb);
}
EXPORT_SYMBOL_GPL(register_dsa_notifier);

int unregister_dsa_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_unregister(&dsa_notif_chain, nb);
}
EXPORT_SYMBOL_GPL(unregister_dsa_notifier);

int call_dsa_notifiers(unsigned long val, struct net_device *dev,
                       struct dsa_notifier_info *info)
{
        info->dev = dev;
        return atomic_notifier_call_chain(&dsa_notif_chain, val, info);
}
EXPORT_SYMBOL_GPL(call_dsa_notifiers);

int dsa_devlink_param_get(struct devlink *dl, u32 id,
                          struct devlink_param_gset_ctx *ctx)
{
        struct dsa_devlink_priv *dl_priv;
        struct dsa_switch *ds;

        dl_priv = devlink_priv(dl);
        ds = dl_priv->ds;

        if (!ds->ops->devlink_param_get)
                return -EOPNOTSUPP;

        return ds->ops->devlink_param_get(ds, id, ctx);
}
EXPORT_SYMBOL_GPL(dsa_devlink_param_get);

int dsa_devlink_param_set(struct devlink *dl, u32 id,
                          struct devlink_param_gset_ctx *ctx)
{
        struct dsa_devlink_priv *dl_priv;
        struct dsa_switch *ds;

        dl_priv = devlink_priv(dl);
        ds = dl_priv->ds;

        if (!ds->ops->devlink_param_set)
                return -EOPNOTSUPP;

        return ds->ops->devlink_param_set(ds, id, ctx);
}
EXPORT_SYMBOL_GPL(dsa_devlink_param_set);

int dsa_devlink_params_register(struct dsa_switch *ds,
                                const struct devlink_param *params,
                                size_t params_count)
{
        return devlink_params_register(ds->devlink, params, params_count);
}
EXPORT_SYMBOL_GPL(dsa_devlink_params_register);

void dsa_devlink_params_unregister(struct dsa_switch *ds,
                                   const struct devlink_param *params,
                                   size_t params_count)
{
        devlink_params_unregister(ds->devlink, params, params_count);
}
EXPORT_SYMBOL_GPL(dsa_devlink_params_unregister);

int dsa_devlink_resource_register(struct dsa_switch *ds,
                                  const char *resource_name,
                                  u64 resource_size,
                                  u64 resource_id,
                                  u64 parent_resource_id,
                                  const struct devlink_resource_size_params *size_params)
{
        return devlink_resource_register(ds->devlink, resource_name,
                                         resource_size, resource_id,
                                         parent_resource_id,
                                         size_params);
}
EXPORT_SYMBOL_GPL(dsa_devlink_resource_register);

void dsa_devlink_resources_unregister(struct dsa_switch *ds)
{
        devlink_resources_unregister(ds->devlink, NULL);
}
EXPORT_SYMBOL_GPL(dsa_devlink_resources_unregister);

void dsa_devlink_resource_occ_get_register(struct dsa_switch *ds,
                                           u64 resource_id,
                                           devlink_resource_occ_get_t *occ_get,
                                           void *occ_get_priv)
{
        return devlink_resource_occ_get_register(ds->devlink, resource_id,
                                                 occ_get, occ_get_priv);
}
EXPORT_SYMBOL_GPL(dsa_devlink_resource_occ_get_register);

void dsa_devlink_resource_occ_get_unregister(struct dsa_switch *ds,
                                             u64 resource_id)
{
        devlink_resource_occ_get_unregister(ds->devlink, resource_id);
}
EXPORT_SYMBOL_GPL(dsa_devlink_resource_occ_get_unregister);

struct dsa_port *dsa_port_from_netdev(struct net_device *netdev)
{
        if (!netdev || !dsa_slave_dev_check(netdev))
                return ERR_PTR(-ENODEV);

        return dsa_slave_to_port(netdev);
}
EXPORT_SYMBOL_GPL(dsa_port_from_netdev);

static int __init dsa_init_module(void)
{
        int rc;

        dsa_owq = alloc_ordered_workqueue("dsa_ordered",
                                          WQ_MEM_RECLAIM);
        if (!dsa_owq)
                return -ENOMEM;

        rc = dsa_slave_register_notifier();
        if (rc)
                goto register_notifier_fail;

        dev_add_pack(&dsa_pack_type);

        dsa_tag_driver_register(&DSA_TAG_DRIVER_NAME(none_ops),
                                THIS_MODULE);

        return 0;

register_notifier_fail:
        destroy_workqueue(dsa_owq);

        return rc;
}
module_init(dsa_init_module);

static void __exit dsa_cleanup_module(void)
{
        dsa_tag_driver_unregister(&DSA_TAG_DRIVER_NAME(none_ops));

        dsa_slave_unregister_notifier();
        dev_remove_pack(&dsa_pack_type);
        destroy_workqueue(dsa_owq);
}
module_exit(dsa_cleanup_module);

MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>");
MODULE_DESCRIPTION("Driver for Distributed Switch Architecture switch chips");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:dsa");