// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2010-2011 EIA Electronics,
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// Kurt Van Dijck <kurt.van.dijck@eia.be>
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// Copyright (c) 2017-2019 Pengutronix,
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// Marc Kleine-Budde <kernel@pengutronix.de>
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// Copyright (c) 2017-2019 Pengutronix,
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// Oleksij Rempel <kernel@pengutronix.de>
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/* bus for j1939 remote devices
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* Since rtnetlink, no real bus is used.
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*/
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#include <net/sock.h>
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#include "j1939-priv.h"
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static void __j1939_ecu_release(struct kref *kref)
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{
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struct j1939_ecu *ecu = container_of(kref, struct j1939_ecu, kref);
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struct j1939_priv *priv = ecu->priv;
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list_del(&ecu->list);
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kfree(ecu);
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j1939_priv_put(priv);
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}
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void j1939_ecu_put(struct j1939_ecu *ecu)
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{
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kref_put(&ecu->kref, __j1939_ecu_release);
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}
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static void j1939_ecu_get(struct j1939_ecu *ecu)
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{
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kref_get(&ecu->kref);
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}
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static bool j1939_ecu_is_mapped_locked(struct j1939_ecu *ecu)
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{
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struct j1939_priv *priv = ecu->priv;
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lockdep_assert_held(&priv->lock);
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return j1939_ecu_find_by_addr_locked(priv, ecu->addr) == ecu;
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}
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/* ECU device interface */
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/* map ECU to a bus address space */
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static void j1939_ecu_map_locked(struct j1939_ecu *ecu)
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{
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struct j1939_priv *priv = ecu->priv;
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struct j1939_addr_ent *ent;
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lockdep_assert_held(&priv->lock);
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if (!j1939_address_is_unicast(ecu->addr))
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return;
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ent = &priv->ents[ecu->addr];
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if (ent->ecu) {
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netdev_warn(priv->ndev, "Trying to map already mapped ECU, addr: 0x%02x, name: 0x%016llx. Skip it.\n",
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ecu->addr, ecu->name);
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return;
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}
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j1939_ecu_get(ecu);
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ent->ecu = ecu;
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ent->nusers += ecu->nusers;
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}
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/* unmap ECU from a bus address space */
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void j1939_ecu_unmap_locked(struct j1939_ecu *ecu)
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{
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struct j1939_priv *priv = ecu->priv;
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struct j1939_addr_ent *ent;
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lockdep_assert_held(&priv->lock);
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if (!j1939_address_is_unicast(ecu->addr))
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return;
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if (!j1939_ecu_is_mapped_locked(ecu))
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return;
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ent = &priv->ents[ecu->addr];
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ent->ecu = NULL;
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ent->nusers -= ecu->nusers;
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j1939_ecu_put(ecu);
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}
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void j1939_ecu_unmap(struct j1939_ecu *ecu)
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{
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write_lock_bh(&ecu->priv->lock);
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j1939_ecu_unmap_locked(ecu);
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write_unlock_bh(&ecu->priv->lock);
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}
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void j1939_ecu_unmap_all(struct j1939_priv *priv)
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{
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int i;
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write_lock_bh(&priv->lock);
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for (i = 0; i < ARRAY_SIZE(priv->ents); i++)
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if (priv->ents[i].ecu)
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j1939_ecu_unmap_locked(priv->ents[i].ecu);
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write_unlock_bh(&priv->lock);
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}
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void j1939_ecu_timer_start(struct j1939_ecu *ecu)
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{
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/* The ECU is held here and released in the
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* j1939_ecu_timer_handler() or j1939_ecu_timer_cancel().
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*/
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j1939_ecu_get(ecu);
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/* Schedule timer in 250 msec to commit address change. */
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hrtimer_start(&ecu->ac_timer, ms_to_ktime(250),
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HRTIMER_MODE_REL_SOFT);
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}
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void j1939_ecu_timer_cancel(struct j1939_ecu *ecu)
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{
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if (hrtimer_cancel(&ecu->ac_timer))
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j1939_ecu_put(ecu);
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}
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static enum hrtimer_restart j1939_ecu_timer_handler(struct hrtimer *hrtimer)
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{
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struct j1939_ecu *ecu =
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container_of(hrtimer, struct j1939_ecu, ac_timer);
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struct j1939_priv *priv = ecu->priv;
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write_lock_bh(&priv->lock);
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/* TODO: can we test if ecu->addr is unicast before starting
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* the timer?
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*/
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j1939_ecu_map_locked(ecu);
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/* The corresponding j1939_ecu_get() is in
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* j1939_ecu_timer_start().
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*/
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j1939_ecu_put(ecu);
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write_unlock_bh(&priv->lock);
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return HRTIMER_NORESTART;
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}
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struct j1939_ecu *j1939_ecu_create_locked(struct j1939_priv *priv, name_t name)
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{
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struct j1939_ecu *ecu;
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lockdep_assert_held(&priv->lock);
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ecu = kzalloc(sizeof(*ecu), gfp_any());
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if (!ecu)
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return ERR_PTR(-ENOMEM);
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kref_init(&ecu->kref);
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ecu->addr = J1939_IDLE_ADDR;
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ecu->name = name;
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hrtimer_init(&ecu->ac_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
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ecu->ac_timer.function = j1939_ecu_timer_handler;
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INIT_LIST_HEAD(&ecu->list);
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j1939_priv_get(priv);
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ecu->priv = priv;
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list_add_tail(&ecu->list, &priv->ecus);
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return ecu;
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}
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struct j1939_ecu *j1939_ecu_find_by_addr_locked(struct j1939_priv *priv,
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u8 addr)
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{
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lockdep_assert_held(&priv->lock);
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return priv->ents[addr].ecu;
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}
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struct j1939_ecu *j1939_ecu_get_by_addr_locked(struct j1939_priv *priv, u8 addr)
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{
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struct j1939_ecu *ecu;
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lockdep_assert_held(&priv->lock);
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if (!j1939_address_is_unicast(addr))
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return NULL;
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ecu = j1939_ecu_find_by_addr_locked(priv, addr);
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if (ecu)
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j1939_ecu_get(ecu);
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return ecu;
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}
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struct j1939_ecu *j1939_ecu_get_by_addr(struct j1939_priv *priv, u8 addr)
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{
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struct j1939_ecu *ecu;
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read_lock_bh(&priv->lock);
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ecu = j1939_ecu_get_by_addr_locked(priv, addr);
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read_unlock_bh(&priv->lock);
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return ecu;
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}
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/* get pointer to ecu without increasing ref counter */
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static struct j1939_ecu *j1939_ecu_find_by_name_locked(struct j1939_priv *priv,
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name_t name)
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{
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struct j1939_ecu *ecu;
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lockdep_assert_held(&priv->lock);
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list_for_each_entry(ecu, &priv->ecus, list) {
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if (ecu->name == name)
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return ecu;
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}
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return NULL;
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}
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struct j1939_ecu *j1939_ecu_get_by_name_locked(struct j1939_priv *priv,
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name_t name)
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{
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struct j1939_ecu *ecu;
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lockdep_assert_held(&priv->lock);
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if (!name)
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return NULL;
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ecu = j1939_ecu_find_by_name_locked(priv, name);
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if (ecu)
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j1939_ecu_get(ecu);
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return ecu;
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}
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struct j1939_ecu *j1939_ecu_get_by_name(struct j1939_priv *priv, name_t name)
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{
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struct j1939_ecu *ecu;
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read_lock_bh(&priv->lock);
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ecu = j1939_ecu_get_by_name_locked(priv, name);
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read_unlock_bh(&priv->lock);
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return ecu;
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}
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u8 j1939_name_to_addr(struct j1939_priv *priv, name_t name)
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{
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struct j1939_ecu *ecu;
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int addr = J1939_IDLE_ADDR;
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if (!name)
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return J1939_NO_ADDR;
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read_lock_bh(&priv->lock);
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ecu = j1939_ecu_find_by_name_locked(priv, name);
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if (ecu && j1939_ecu_is_mapped_locked(ecu))
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/* ecu's SA is registered */
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addr = ecu->addr;
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read_unlock_bh(&priv->lock);
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return addr;
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}
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/* TX addr/name accounting
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* Transport protocol needs to know if a SA is local or not
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* These functions originate from userspace manipulating sockets,
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* so locking is straigforward
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*/
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int j1939_local_ecu_get(struct j1939_priv *priv, name_t name, u8 sa)
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{
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struct j1939_ecu *ecu;
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int err = 0;
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write_lock_bh(&priv->lock);
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if (j1939_address_is_unicast(sa))
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priv->ents[sa].nusers++;
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if (!name)
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goto done;
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ecu = j1939_ecu_get_by_name_locked(priv, name);
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if (!ecu)
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ecu = j1939_ecu_create_locked(priv, name);
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err = PTR_ERR_OR_ZERO(ecu);
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if (err)
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goto done;
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ecu->nusers++;
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/* TODO: do we care if ecu->addr != sa? */
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if (j1939_ecu_is_mapped_locked(ecu))
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/* ecu's sa is active already */
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priv->ents[ecu->addr].nusers++;
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done:
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write_unlock_bh(&priv->lock);
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return err;
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}
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void j1939_local_ecu_put(struct j1939_priv *priv, name_t name, u8 sa)
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{
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struct j1939_ecu *ecu;
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write_lock_bh(&priv->lock);
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if (j1939_address_is_unicast(sa))
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priv->ents[sa].nusers--;
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if (!name)
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goto done;
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ecu = j1939_ecu_find_by_name_locked(priv, name);
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if (WARN_ON_ONCE(!ecu))
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goto done;
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ecu->nusers--;
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/* TODO: do we care if ecu->addr != sa? */
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if (j1939_ecu_is_mapped_locked(ecu))
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/* ecu's sa is active already */
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priv->ents[ecu->addr].nusers--;
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j1939_ecu_put(ecu);
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done:
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write_unlock_bh(&priv->lock);
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}
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