acrn-kernel/net/can/j1939/bus.c

334 lines
7.0 KiB
C

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