// 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;

  	char module_name[128];
  	bool found = false;

  	snprintf(module_name, 127, "%s%d", DSA_TAG_DRIVER_ALIAS,
  		 tag_protocol);

  	request_module(module_name);
  
  	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;

  	netif_receive_skb(skb);
  
  	return 0;

  }

  #ifdef CONFIG_PM_SLEEP

  static bool dsa_is_port_initialized(struct dsa_switch *ds, int p)
  {

  	return dsa_is_user_port(ds, p) && ds->ports[p].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(ds->ports[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(ds->ports[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);

  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");