1 files changed, 333 insertions, 0 deletions
diff --git a/net/can/j1939/bus.c b/net/can/j1939/bus.c
new file mode 100644
index 000000000000..486687901602
--- /dev/null
+++ b/net/can/j1939/bus.c
@@ -0,0 +1,333 @@
+// 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);
+}