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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
* Copyright (C) 2006 Andrey Volkov, Varma Electronics
* Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/workqueue.h>
#include <linux/can.h>
#include <linux/can/can-ml.h>
#include <linux/can/dev.h>
#include <linux/can/skb.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
static void can_update_state_error_stats(struct net_device *dev,
enum can_state new_state)
{
struct can_priv *priv = netdev_priv(dev);
if (new_state <= priv->state)
return;
switch (new_state) {
case CAN_STATE_ERROR_WARNING:
priv->can_stats.error_warning++;
break;
case CAN_STATE_ERROR_PASSIVE:
priv->can_stats.error_passive++;
break;
case CAN_STATE_BUS_OFF:
priv->can_stats.bus_off++;
break;
default:
break;
}
}
static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
{
switch (state) {
case CAN_STATE_ERROR_ACTIVE:
return CAN_ERR_CRTL_ACTIVE;
case CAN_STATE_ERROR_WARNING:
return CAN_ERR_CRTL_TX_WARNING;
case CAN_STATE_ERROR_PASSIVE:
return CAN_ERR_CRTL_TX_PASSIVE;
default:
return 0;
}
}
static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
{
switch (state) {
case CAN_STATE_ERROR_ACTIVE:
return CAN_ERR_CRTL_ACTIVE;
case CAN_STATE_ERROR_WARNING:
return CAN_ERR_CRTL_RX_WARNING;
case CAN_STATE_ERROR_PASSIVE:
return CAN_ERR_CRTL_RX_PASSIVE;
default:
return 0;
}
}
const char *can_get_state_str(const enum can_state state)
{
switch (state) {
case CAN_STATE_ERROR_ACTIVE:
return "Error Active";
case CAN_STATE_ERROR_WARNING:
return "Error Warning";
case CAN_STATE_ERROR_PASSIVE:
return "Error Passive";
case CAN_STATE_BUS_OFF:
return "Bus Off";
case CAN_STATE_STOPPED:
return "Stopped";
case CAN_STATE_SLEEPING:
return "Sleeping";
default:
return "<unknown>";
}
return "<unknown>";
}
EXPORT_SYMBOL_GPL(can_get_state_str);
static enum can_state can_state_err_to_state(u16 err)
{
if (err < CAN_ERROR_WARNING_THRESHOLD)
return CAN_STATE_ERROR_ACTIVE;
if (err < CAN_ERROR_PASSIVE_THRESHOLD)
return CAN_STATE_ERROR_WARNING;
if (err < CAN_BUS_OFF_THRESHOLD)
return CAN_STATE_ERROR_PASSIVE;
return CAN_STATE_BUS_OFF;
}
void can_state_get_by_berr_counter(const struct net_device *dev,
const struct can_berr_counter *bec,
enum can_state *tx_state,
enum can_state *rx_state)
{
*tx_state = can_state_err_to_state(bec->txerr);
*rx_state = can_state_err_to_state(bec->rxerr);
}
EXPORT_SYMBOL_GPL(can_state_get_by_berr_counter);
void can_change_state(struct net_device *dev, struct can_frame *cf,
enum can_state tx_state, enum can_state rx_state)
{
struct can_priv *priv = netdev_priv(dev);
enum can_state new_state = max(tx_state, rx_state);
if (unlikely(new_state == priv->state)) {
netdev_warn(dev, "%s: oops, state did not change", __func__);
return;
}
netdev_dbg(dev, "Controller changed from %s State (%d) into %s State (%d).\n",
can_get_state_str(priv->state), priv->state,
can_get_state_str(new_state), new_state);
can_update_state_error_stats(dev, new_state);
priv->state = new_state;
if (!cf)
return;
if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
cf->can_id |= CAN_ERR_BUSOFF;
return;
}
cf->can_id |= CAN_ERR_CRTL;
cf->data[1] |= tx_state >= rx_state ?
can_tx_state_to_frame(dev, tx_state) : 0;
cf->data[1] |= tx_state <= rx_state ?
can_rx_state_to_frame(dev, rx_state) : 0;
}
EXPORT_SYMBOL_GPL(can_change_state);
/* CAN device restart for bus-off recovery */
static void can_restart(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
struct sk_buff *skb;
struct can_frame *cf;
int err;
if (netif_carrier_ok(dev))
netdev_err(dev, "Attempt to restart for bus-off recovery, but carrier is OK?\n");
/* No synchronization needed because the device is bus-off and
* no messages can come in or go out.
*/
can_flush_echo_skb(dev);
/* send restart message upstream */
skb = alloc_can_err_skb(dev, &cf);
if (skb) {
cf->can_id |= CAN_ERR_RESTARTED;
netif_rx(skb);
}
/* Now restart the device */
netif_carrier_on(dev);
err = priv->do_set_mode(dev, CAN_MODE_START);
if (err) {
netdev_err(dev, "Restart failed, error %pe\n", ERR_PTR(err));
netif_carrier_off(dev);
} else {
netdev_dbg(dev, "Restarted\n");
priv->can_stats.restarts++;
}
}
static void can_restart_work(struct work_struct *work)
{
struct delayed_work *dwork = to_delayed_work(work);
struct can_priv *priv = container_of(dwork, struct can_priv,
restart_work);
can_restart(priv->dev);
}
int can_restart_now(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
/* A manual restart is only permitted if automatic restart is
* disabled and the device is in the bus-off state
*/
if (priv->restart_ms)
return -EINVAL;
if (priv->state != CAN_STATE_BUS_OFF)
return -EBUSY;
cancel_delayed_work_sync(&priv->restart_work);
can_restart(dev);
return 0;
}
/* CAN bus-off
*
* This functions should be called when the device goes bus-off to
* tell the netif layer that no more packets can be sent or received.
* If enabled, a timer is started to trigger bus-off recovery.
*/
void can_bus_off(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
if (priv->restart_ms)
netdev_info(dev, "bus-off, scheduling restart in %d ms\n",
priv->restart_ms);
else
netdev_info(dev, "bus-off\n");
netif_carrier_off(dev);
if (priv->restart_ms)
schedule_delayed_work(&priv->restart_work,
msecs_to_jiffies(priv->restart_ms));
}
EXPORT_SYMBOL_GPL(can_bus_off);
void can_setup(struct net_device *dev)
{
dev->type = ARPHRD_CAN;
dev->mtu = CAN_MTU;
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->tx_queue_len = 10;
/* New-style flags. */
dev->flags = IFF_NOARP;
dev->features = NETIF_F_HW_CSUM;
}
/* Allocate and setup space for the CAN network device */
struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
unsigned int txqs, unsigned int rxqs)
{
struct can_ml_priv *can_ml;
struct net_device *dev;
struct can_priv *priv;
int size;
/* We put the driver's priv, the CAN mid layer priv and the
* echo skb into the netdevice's priv. The memory layout for
* the netdev_priv is like this:
*
* +-------------------------+
* | driver's priv |
* +-------------------------+
* | struct can_ml_priv |
* +-------------------------+
* | array of struct sk_buff |
* +-------------------------+
*/
size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv);
if (echo_skb_max)
size = ALIGN(size, sizeof(struct sk_buff *)) +
echo_skb_max * sizeof(struct sk_buff *);
dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
txqs, rxqs);
if (!dev)
return NULL;
priv = netdev_priv(dev);
priv->dev = dev;
can_ml = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN);
can_set_ml_priv(dev, can_ml);
if (echo_skb_max) {
priv->echo_skb_max = echo_skb_max;
priv->echo_skb = (void *)priv +
(size - echo_skb_max * sizeof(struct sk_buff *));
}
priv->state = CAN_STATE_STOPPED;
INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
return dev;
}
EXPORT_SYMBOL_GPL(alloc_candev_mqs);
/* Free space of the CAN network device */
void free_candev(struct net_device *dev)
{
free_netdev(dev);
}
EXPORT_SYMBOL_GPL(free_candev);
/* changing MTU and control mode for CAN/CANFD devices */
int can_change_mtu(struct net_device *dev, int new_mtu)
{
struct can_priv *priv = netdev_priv(dev);
u32 ctrlmode_static = can_get_static_ctrlmode(priv);
/* Do not allow changing the MTU while running */
if (dev->flags & IFF_UP)
return -EBUSY;
/* allow change of MTU according to the CANFD ability of the device */
switch (new_mtu) {
case CAN_MTU:
/* 'CANFD-only' controllers can not switch to CAN_MTU */
if (ctrlmode_static & CAN_CTRLMODE_FD)
return -EINVAL;
priv->ctrlmode &= ~CAN_CTRLMODE_FD;
break;
case CANFD_MTU:
/* check for potential CANFD ability */
if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
!(ctrlmode_static & CAN_CTRLMODE_FD))
return -EINVAL;
priv->ctrlmode |= CAN_CTRLMODE_FD;
break;
default:
return -EINVAL;
}
dev->mtu = new_mtu;
return 0;
}
EXPORT_SYMBOL_GPL(can_change_mtu);
/* generic implementation of netdev_ops::ndo_eth_ioctl for CAN devices
* supporting hardware timestamps
*/
int can_eth_ioctl_hwts(struct net_device *netdev, struct ifreq *ifr, int cmd)
{
struct hwtstamp_config hwts_cfg = { 0 };
switch (cmd) {
case SIOCSHWTSTAMP: /* set */
if (copy_from_user(&hwts_cfg, ifr->ifr_data, sizeof(hwts_cfg)))
return -EFAULT;
if (hwts_cfg.tx_type == HWTSTAMP_TX_ON &&
hwts_cfg.rx_filter == HWTSTAMP_FILTER_ALL)
return 0;
return -ERANGE;
case SIOCGHWTSTAMP: /* get */
hwts_cfg.tx_type = HWTSTAMP_TX_ON;
hwts_cfg.rx_filter = HWTSTAMP_FILTER_ALL;
if (copy_to_user(ifr->ifr_data, &hwts_cfg, sizeof(hwts_cfg)))
return -EFAULT;
return 0;
default:
return -EOPNOTSUPP;
}
}
EXPORT_SYMBOL(can_eth_ioctl_hwts);
/* generic implementation of ethtool_ops::get_ts_info for CAN devices
* supporting hardware timestamps
*/
int can_ethtool_op_get_ts_info_hwts(struct net_device *dev,
struct ethtool_ts_info *info)
{
info->so_timestamping =
SOF_TIMESTAMPING_TX_SOFTWARE |
SOF_TIMESTAMPING_RX_SOFTWARE |
SOF_TIMESTAMPING_SOFTWARE |
SOF_TIMESTAMPING_TX_HARDWARE |
SOF_TIMESTAMPING_RX_HARDWARE |
SOF_TIMESTAMPING_RAW_HARDWARE;
info->phc_index = -1;
info->tx_types = BIT(HWTSTAMP_TX_ON);
info->rx_filters = BIT(HWTSTAMP_FILTER_ALL);
return 0;
}
EXPORT_SYMBOL(can_ethtool_op_get_ts_info_hwts);
/* Common open function when the device gets opened.
*
* This function should be called in the open function of the device
* driver.
*/
int open_candev(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
if (!priv->bittiming.bitrate) {
netdev_err(dev, "bit-timing not yet defined\n");
return -EINVAL;
}
/* For CAN FD the data bitrate has to be >= the arbitration bitrate */
if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
(!priv->data_bittiming.bitrate ||
priv->data_bittiming.bitrate < priv->bittiming.bitrate)) {
netdev_err(dev, "incorrect/missing data bit-timing\n");
return -EINVAL;
}
/* Switch carrier on if device was stopped while in bus-off state */
if (!netif_carrier_ok(dev))
netif_carrier_on(dev);
return 0;
}
EXPORT_SYMBOL_GPL(open_candev);
#ifdef CONFIG_OF
/* Common function that can be used to understand the limitation of
* a transceiver when it provides no means to determine these limitations
* at runtime.
*/
void of_can_transceiver(struct net_device *dev)
{
struct device_node *dn;
struct can_priv *priv = netdev_priv(dev);
struct device_node *np = dev->dev.parent->of_node;
int ret;
dn = of_get_child_by_name(np, "can-transceiver");
if (!dn)
return;
ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
of_node_put(dn);
if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
}
EXPORT_SYMBOL_GPL(of_can_transceiver);
#endif
/* Common close function for cleanup before the device gets closed.
*
* This function should be called in the close function of the device
* driver.
*/
void close_candev(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
cancel_delayed_work_sync(&priv->restart_work);
can_flush_echo_skb(dev);
}
EXPORT_SYMBOL_GPL(close_candev);
static int can_set_termination(struct net_device *ndev, u16 term)
{
struct can_priv *priv = netdev_priv(ndev);
int set;
if (term == priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED])
set = 1;
else
set = 0;
gpiod_set_value(priv->termination_gpio, set);
return 0;
}
static int can_get_termination(struct net_device *ndev)
{
struct can_priv *priv = netdev_priv(ndev);
struct device *dev = ndev->dev.parent;
struct gpio_desc *gpio;
u32 term;
int ret;
/* Disabling termination by default is the safe choice: Else if many
* bus participants enable it, no communication is possible at all.
*/
gpio = devm_gpiod_get_optional(dev, "termination", GPIOD_OUT_LOW);
if (IS_ERR(gpio))
return dev_err_probe(dev, PTR_ERR(gpio),
"Cannot get termination-gpios\n");
if (!gpio)
return 0;
ret = device_property_read_u32(dev, "termination-ohms", &term);
if (ret) {
netdev_err(ndev, "Cannot get termination-ohms: %pe\n",
ERR_PTR(ret));
return ret;
}
if (term > U16_MAX) {
netdev_err(ndev, "Invalid termination-ohms value (%u > %u)\n",
term, U16_MAX);
return -EINVAL;
}
priv->termination_const_cnt = ARRAY_SIZE(priv->termination_gpio_ohms);
priv->termination_const = priv->termination_gpio_ohms;
priv->termination_gpio = gpio;
priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_DISABLED] =
CAN_TERMINATION_DISABLED;
priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED] = term;
priv->do_set_termination = can_set_termination;
return 0;
}
static bool
can_bittiming_const_valid(const struct can_bittiming_const *btc)
{
if (!btc)
return true;
if (!btc->sjw_max)
return false;
return true;
}
/* Register the CAN network device */
int register_candev(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
int err;
/* Ensure termination_const, termination_const_cnt and
* do_set_termination consistency. All must be either set or
* unset.
*/
if ((!priv->termination_const != !priv->termination_const_cnt) ||
(!priv->termination_const != !priv->do_set_termination))
return -EINVAL;
if (!priv->bitrate_const != !priv->bitrate_const_cnt)
return -EINVAL;
if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
return -EINVAL;
/* We only support either fixed bit rates or bit timing const. */
if ((priv->bitrate_const || priv->data_bitrate_const) &&
(priv->bittiming_const || priv->data_bittiming_const))
return -EINVAL;
if (!can_bittiming_const_valid(priv->bittiming_const) ||
!can_bittiming_const_valid(priv->data_bittiming_const))
return -EINVAL;
if (!priv->termination_const) {
err = can_get_termination(dev);
if (err)
return err;
}
dev->rtnl_link_ops = &can_link_ops;
netif_carrier_off(dev);
return register_netdev(dev);
}
EXPORT_SYMBOL_GPL(register_candev);
/* Unregister the CAN network device */
void unregister_candev(struct net_device *dev)
{
unregister_netdev(dev);
}
EXPORT_SYMBOL_GPL(unregister_candev);
/* Test if a network device is a candev based device
* and return the can_priv* if so.
*/
struct can_priv *safe_candev_priv(struct net_device *dev)
{
if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops)
return NULL;
return netdev_priv(dev);
}
EXPORT_SYMBOL_GPL(safe_candev_priv);
static __init int can_dev_init(void)
{
int err;
err = can_netlink_register();
if (!err)
pr_info("CAN device driver interface\n");
return err;
}
module_init(can_dev_init);
static __exit void can_dev_exit(void)
{
can_netlink_unregister();
}
module_exit(can_dev_exit);
MODULE_ALIAS_RTNL_LINK("can");