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-rw-r--r--net/can/j1939/bus.c333
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);
+}