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linux/drivers/net/can/dev.c

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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/module.h>
#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/can/netlink.h>
#include <linux/can/led.h>
#include <linux/of.h>
#include <net/rtnetlink.h>
#define MOD_DESC "CAN device driver interface"
MODULE_DESCRIPTION(MOD_DESC);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
/* CAN DLC to real data length conversion helpers */
static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
8, 12, 16, 20, 24, 32, 48, 64};
/* get data length from can_dlc with sanitized can_dlc */
u8 can_dlc2len(u8 can_dlc)
{
return dlc2len[can_dlc & 0x0F];
}
EXPORT_SYMBOL_GPL(can_dlc2len);
static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, /* 0 - 8 */
9, 9, 9, 9, /* 9 - 12 */
10, 10, 10, 10, /* 13 - 16 */
11, 11, 11, 11, /* 17 - 20 */
12, 12, 12, 12, /* 21 - 24 */
13, 13, 13, 13, 13, 13, 13, 13, /* 25 - 32 */
14, 14, 14, 14, 14, 14, 14, 14, /* 33 - 40 */
14, 14, 14, 14, 14, 14, 14, 14, /* 41 - 48 */
15, 15, 15, 15, 15, 15, 15, 15, /* 49 - 56 */
15, 15, 15, 15, 15, 15, 15, 15}; /* 57 - 64 */
/* map the sanitized data length to an appropriate data length code */
u8 can_len2dlc(u8 len)
{
if (unlikely(len > 64))
return 0xF;
return len2dlc[len];
}
EXPORT_SYMBOL_GPL(can_len2dlc);
#ifdef CONFIG_CAN_CALC_BITTIMING
#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
#define CAN_CALC_SYNC_SEG 1
/* Bit-timing calculation derived from:
*
* Code based on LinCAN sources and H8S2638 project
* Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
* Copyright 2005 Stanislav Marek
* email: pisa@cmp.felk.cvut.cz
*
* Calculates proper bit-timing parameters for a specified bit-rate
* and sample-point, which can then be used to set the bit-timing
* registers of the CAN controller. You can find more information
* in the header file linux/can/netlink.h.
*/
static int
can_update_sample_point(const struct can_bittiming_const *btc,
unsigned int sample_point_nominal, unsigned int tseg,
unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
unsigned int *sample_point_error_ptr)
{
unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
unsigned int sample_point, best_sample_point = 0;
unsigned int tseg1, tseg2;
int i;
for (i = 0; i <= 1; i++) {
tseg2 = tseg + CAN_CALC_SYNC_SEG -
(sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) /
1000 - i;
tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
tseg1 = tseg - tseg2;
if (tseg1 > btc->tseg1_max) {
tseg1 = btc->tseg1_max;
tseg2 = tseg - tseg1;
}
sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) /
(tseg + CAN_CALC_SYNC_SEG);
sample_point_error = abs(sample_point_nominal - sample_point);
if (sample_point <= sample_point_nominal &&
sample_point_error < best_sample_point_error) {
best_sample_point = sample_point;
best_sample_point_error = sample_point_error;
*tseg1_ptr = tseg1;
*tseg2_ptr = tseg2;
}
}
if (sample_point_error_ptr)
*sample_point_error_ptr = best_sample_point_error;
return best_sample_point;
}
static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc)
{
struct can_priv *priv = netdev_priv(dev);
unsigned int bitrate; /* current bitrate */
unsigned int bitrate_error; /* difference between current and nominal value */
unsigned int best_bitrate_error = UINT_MAX;
unsigned int sample_point_error; /* difference between current and nominal value */
unsigned int best_sample_point_error = UINT_MAX;
unsigned int sample_point_nominal; /* nominal sample point */
unsigned int best_tseg = 0; /* current best value for tseg */
unsigned int best_brp = 0; /* current best value for brp */
unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
u64 v64;
/* Use CiA recommended sample points */
if (bt->sample_point) {
sample_point_nominal = bt->sample_point;
} else {
if (bt->bitrate > 800000)
sample_point_nominal = 750;
else if (bt->bitrate > 500000)
sample_point_nominal = 800;
else
sample_point_nominal = 875;
}
/* tseg even = round down, odd = round up */
for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
/* Compute all possible tseg choices (tseg=tseg1+tseg2) */
brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
/* choose brp step which is possible in system */
brp = (brp / btc->brp_inc) * btc->brp_inc;
if (brp < btc->brp_min || brp > btc->brp_max)
continue;
bitrate = priv->clock.freq / (brp * tsegall);
bitrate_error = abs(bt->bitrate - bitrate);
/* tseg brp biterror */
if (bitrate_error > best_bitrate_error)
continue;
/* reset sample point error if we have a better bitrate */
if (bitrate_error < best_bitrate_error)
best_sample_point_error = UINT_MAX;
can_update_sample_point(btc, sample_point_nominal, tseg / 2,
&tseg1, &tseg2, &sample_point_error);
if (sample_point_error > best_sample_point_error)
continue;
best_sample_point_error = sample_point_error;
best_bitrate_error = bitrate_error;
best_tseg = tseg / 2;
best_brp = brp;
if (bitrate_error == 0 && sample_point_error == 0)
break;
}
if (best_bitrate_error) {
/* Error in one-tenth of a percent */
v64 = (u64)best_bitrate_error * 1000;
do_div(v64, bt->bitrate);
bitrate_error = (u32)v64;
if (bitrate_error > CAN_CALC_MAX_ERROR) {
netdev_err(dev,
"bitrate error %d.%d%% too high\n",
bitrate_error / 10, bitrate_error % 10);
return -EDOM;
}
netdev_warn(dev, "bitrate error %d.%d%%\n",
bitrate_error / 10, bitrate_error % 10);
}
/* real sample point */
bt->sample_point = can_update_sample_point(btc, sample_point_nominal,
best_tseg, &tseg1, &tseg2,
NULL);
v64 = (u64)best_brp * 1000 * 1000 * 1000;
do_div(v64, priv->clock.freq);
bt->tq = (u32)v64;
bt->prop_seg = tseg1 / 2;
bt->phase_seg1 = tseg1 - bt->prop_seg;
bt->phase_seg2 = tseg2;
/* check for sjw user settings */
if (!bt->sjw || !btc->sjw_max) {
bt->sjw = 1;
} else {
/* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
if (bt->sjw > btc->sjw_max)
bt->sjw = btc->sjw_max;
/* bt->sjw must not be higher than tseg2 */
if (tseg2 < bt->sjw)
bt->sjw = tseg2;
}
bt->brp = best_brp;
/* real bitrate */
bt->bitrate = priv->clock.freq /
(bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
return 0;
}
#else /* !CONFIG_CAN_CALC_BITTIMING */
static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc)
{
netdev_err(dev, "bit-timing calculation not available\n");
return -EINVAL;
}
#endif /* CONFIG_CAN_CALC_BITTIMING */
/* Checks the validity of the specified bit-timing parameters prop_seg,
* phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
* prescaler value brp. You can find more information in the header
* file linux/can/netlink.h.
*/
static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc)
{
struct can_priv *priv = netdev_priv(dev);
int tseg1, alltseg;
u64 brp64;
tseg1 = bt->prop_seg + bt->phase_seg1;
if (!bt->sjw)
bt->sjw = 1;
if (bt->sjw > btc->sjw_max ||
tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
return -ERANGE;
brp64 = (u64)priv->clock.freq * (u64)bt->tq;
if (btc->brp_inc > 1)
do_div(brp64, btc->brp_inc);
brp64 += 500000000UL - 1;
do_div(brp64, 1000000000UL); /* the practicable BRP */
if (btc->brp_inc > 1)
brp64 *= btc->brp_inc;
bt->brp = (u32)brp64;
if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
return -EINVAL;
alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
return 0;
}
/* Checks the validity of predefined bitrate settings */
static int
can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
const u32 *bitrate_const,
const unsigned int bitrate_const_cnt)
{
struct can_priv *priv = netdev_priv(dev);
unsigned int i;
for (i = 0; i < bitrate_const_cnt; i++) {
if (bt->bitrate == bitrate_const[i])
break;
}
if (i >= priv->bitrate_const_cnt)
return -EINVAL;
return 0;
}
static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc,
const u32 *bitrate_const,
const unsigned int bitrate_const_cnt)
{
int err;
/* Depending on the given can_bittiming parameter structure the CAN
* timing parameters are calculated based on the provided bitrate OR
* alternatively the CAN timing parameters (tq, prop_seg, etc.) are
* provided directly which are then checked and fixed up.
*/
if (!bt->tq && bt->bitrate && btc)
err = can_calc_bittiming(dev, bt, btc);
else if (bt->tq && !bt->bitrate && btc)
err = can_fixup_bittiming(dev, bt, btc);
else if (!bt->tq && bt->bitrate && bitrate_const)
err = can_validate_bitrate(dev, bt, bitrate_const,
bitrate_const_cnt);
else
err = -EINVAL;
return err;
}
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;
}
}
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, "New error state: %d\n", 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);
/* Local echo of CAN messages
*
* CAN network devices *should* support a local echo functionality
* (see Documentation/networking/can.rst). To test the handling of CAN
* interfaces that do not support the local echo both driver types are
* implemented. In the case that the driver does not support the echo
* the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
* to perform the echo as a fallback solution.
*/
static void can_flush_echo_skb(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
int i;
for (i = 0; i < priv->echo_skb_max; i++) {
if (priv->echo_skb[i]) {
kfree_skb(priv->echo_skb[i]);
priv->echo_skb[i] = NULL;
stats->tx_dropped++;
stats->tx_aborted_errors++;
}
}
}
/* Put the skb on the stack to be looped backed locally lateron
*
* The function is typically called in the start_xmit function
* of the device driver. The driver must protect access to
* priv->echo_skb, if necessary.
*/
void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
unsigned int idx)
{
struct can_priv *priv = netdev_priv(dev);
BUG_ON(idx >= priv->echo_skb_max);
/* check flag whether this packet has to be looped back */
if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
(skb->protocol != htons(ETH_P_CAN) &&
skb->protocol != htons(ETH_P_CANFD))) {
kfree_skb(skb);
return;
}
if (!priv->echo_skb[idx]) {
skb = can_create_echo_skb(skb);
if (!skb)
return;
/* make settings for echo to reduce code in irq context */
skb->pkt_type = PACKET_BROADCAST;
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->dev = dev;
/* save this skb for tx interrupt echo handling */
priv->echo_skb[idx] = skb;
} else {
/* locking problem with netif_stop_queue() ?? */
netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
kfree_skb(skb);
}
}
EXPORT_SYMBOL_GPL(can_put_echo_skb);
struct sk_buff *
__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
{
struct can_priv *priv = netdev_priv(dev);
if (idx >= priv->echo_skb_max) {
netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
__func__, idx, priv->echo_skb_max);
return NULL;
}
if (priv->echo_skb[idx]) {
/* Using "struct canfd_frame::len" for the frame
* length is supported on both CAN and CANFD frames.
*/
struct sk_buff *skb = priv->echo_skb[idx];
struct canfd_frame *cf = (struct canfd_frame *)skb->data;
u8 len = cf->len;
*len_ptr = len;
priv->echo_skb[idx] = NULL;
return skb;
}
return NULL;
}
/* Get the skb from the stack and loop it back locally
*
* The function is typically called when the TX done interrupt
* is handled in the device driver. The driver must protect
* access to priv->echo_skb, if necessary.
*/
unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
{
struct sk_buff *skb;
u8 len;
skb = __can_get_echo_skb(dev, idx, &len);
if (!skb)
return 0;
netif_rx(skb);
return len;
}
EXPORT_SYMBOL_GPL(can_get_echo_skb);
/* Remove the skb from the stack and free it.
*
* The function is typically called when TX failed.
*/
void can_free_echo_skb(struct net_device *dev, unsigned int idx)
{
struct can_priv *priv = netdev_priv(dev);
BUG_ON(idx >= priv->echo_skb_max);
if (priv->echo_skb[idx]) {
dev_kfree_skb_any(priv->echo_skb[idx]);
priv->echo_skb[idx] = NULL;
}
}
EXPORT_SYMBOL_GPL(can_free_echo_skb);
/* CAN device restart for bus-off recovery */
static void can_restart(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct sk_buff *skb;
struct can_frame *cf;
int err;
BUG_ON(netif_carrier_ok(dev));
/* 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)
goto restart;
cf->can_id |= CAN_ERR_RESTARTED;
netif_rx(skb);
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
restart:
netdev_dbg(dev, "restarted\n");
priv->can_stats.restarts++;
/* Now restart the device */
err = priv->do_set_mode(dev, CAN_MODE_START);
netif_carrier_on(dev);
if (err)
netdev_err(dev, "Error %d during restart", err);
}
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);
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);
static 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;
}
struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
{
struct sk_buff *skb;
skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
sizeof(struct can_frame));
if (unlikely(!skb))
return NULL;
skb->protocol = htons(ETH_P_CAN);
skb->pkt_type = PACKET_BROADCAST;
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
*cf = skb_put_zero(skb, sizeof(struct can_frame));
return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_skb);
struct sk_buff *alloc_canfd_skb(struct net_device *dev,
struct canfd_frame **cfd)
{
struct sk_buff *skb;
skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
sizeof(struct canfd_frame));
if (unlikely(!skb))
return NULL;
skb->protocol = htons(ETH_P_CANFD);
skb->pkt_type = PACKET_BROADCAST;
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
*cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
return skb;
}
EXPORT_SYMBOL_GPL(alloc_canfd_skb);
struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
{
struct sk_buff *skb;
skb = alloc_can_skb(dev, cf);
if (unlikely(!skb))
return NULL;
(*cf)->can_id = CAN_ERR_FLAG;
(*cf)->can_dlc = CAN_ERR_DLC;
return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_err_skb);
/* 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 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;
dev->ml_priv = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN);
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);
/* 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 (priv->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) &&
!(priv->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);
/* 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);
/* CAN netlink interface */
static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
[IFLA_CAN_STATE] = { .type = NLA_U32 },
[IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
[IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
[IFLA_CAN_RESTART] = { .type = NLA_U32 },
[IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
[IFLA_CAN_BITTIMING_CONST]
= { .len = sizeof(struct can_bittiming_const) },
[IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
[IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
[IFLA_CAN_DATA_BITTIMING]
= { .len = sizeof(struct can_bittiming) },
[IFLA_CAN_DATA_BITTIMING_CONST]
= { .len = sizeof(struct can_bittiming_const) },
[IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
};
static int can_validate(struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
bool is_can_fd = false;
/* Make sure that valid CAN FD configurations always consist of
* - nominal/arbitration bittiming
* - data bittiming
* - control mode with CAN_CTRLMODE_FD set
*/
if (!data)
return 0;
if (data[IFLA_CAN_CTRLMODE]) {
struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
}
if (is_can_fd) {
if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
return -EOPNOTSUPP;
}
if (data[IFLA_CAN_DATA_BITTIMING]) {
if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
return -EOPNOTSUPP;
}
return 0;
}
static int can_changelink(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[],
struct netlink_ext_ack *extack)
{
struct can_priv *priv = netdev_priv(dev);
int err;
/* We need synchronization with dev->stop() */
ASSERT_RTNL();
if (data[IFLA_CAN_BITTIMING]) {
struct can_bittiming bt;
/* Do not allow changing bittiming while running */
if (dev->flags & IFF_UP)
return -EBUSY;
/* Calculate bittiming parameters based on
* bittiming_const if set, otherwise pass bitrate
* directly via do_set_bitrate(). Bail out if neither
* is given.
*/
if (!priv->bittiming_const && !priv->do_set_bittiming)
return -EOPNOTSUPP;
memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
err = can_get_bittiming(dev, &bt,
priv->bittiming_const,
priv->bitrate_const,
priv->bitrate_const_cnt);
if (err)
return err;
if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
priv->bitrate_max);
return -EINVAL;
}
memcpy(&priv->bittiming, &bt, sizeof(bt));
if (priv->do_set_bittiming) {
/* Finally, set the bit-timing registers */
err = priv->do_set_bittiming(dev);
if (err)
return err;
}
}
if (data[IFLA_CAN_CTRLMODE]) {
struct can_ctrlmode *cm;
u32 ctrlstatic;
u32 maskedflags;
/* Do not allow changing controller mode while running */
if (dev->flags & IFF_UP)
return -EBUSY;
cm = nla_data(data[IFLA_CAN_CTRLMODE]);
ctrlstatic = priv->ctrlmode_static;
maskedflags = cm->flags & cm->mask;
/* check whether provided bits are allowed to be passed */
if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
return -EOPNOTSUPP;
/* do not check for static fd-non-iso if 'fd' is disabled */
if (!(maskedflags & CAN_CTRLMODE_FD))
ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
/* make sure static options are provided by configuration */
if ((maskedflags & ctrlstatic) != ctrlstatic)
return -EOPNOTSUPP;
/* clear bits to be modified and copy the flag values */
priv->ctrlmode &= ~cm->mask;
priv->ctrlmode |= maskedflags;
/* CAN_CTRLMODE_FD can only be set when driver supports FD */
if (priv->ctrlmode & CAN_CTRLMODE_FD)
dev->mtu = CANFD_MTU;
else
dev->mtu = CAN_MTU;
}
if (data[IFLA_CAN_RESTART_MS]) {
/* Do not allow changing restart delay while running */
if (dev->flags & IFF_UP)
return -EBUSY;
priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
}
if (data[IFLA_CAN_RESTART]) {
/* Do not allow a restart while not running */
if (!(dev->flags & IFF_UP))
return -EINVAL;
err = can_restart_now(dev);
if (err)
return err;
}
if (data[IFLA_CAN_DATA_BITTIMING]) {
struct can_bittiming dbt;
/* Do not allow changing bittiming while running */
if (dev->flags & IFF_UP)
return -EBUSY;
/* Calculate bittiming parameters based on
* data_bittiming_const if set, otherwise pass bitrate
* directly via do_set_bitrate(). Bail out if neither
* is given.
*/
if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
return -EOPNOTSUPP;
memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
sizeof(dbt));
err = can_get_bittiming(dev, &dbt,
priv->data_bittiming_const,
priv->data_bitrate_const,
priv->data_bitrate_const_cnt);
if (err)
return err;
if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
priv->bitrate_max);
return -EINVAL;
}
memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
if (priv->do_set_data_bittiming) {
/* Finally, set the bit-timing registers */
err = priv->do_set_data_bittiming(dev);
if (err)
return err;
}
}
if (data[IFLA_CAN_TERMINATION]) {
const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
const unsigned int num_term = priv->termination_const_cnt;
unsigned int i;
if (!priv->do_set_termination)
return -EOPNOTSUPP;
/* check whether given value is supported by the interface */
for (i = 0; i < num_term; i++) {
if (termval == priv->termination_const[i])
break;
}
if (i >= num_term)
return -EINVAL;
/* Finally, set the termination value */
err = priv->do_set_termination(dev, termval);
if (err)
return err;
priv->termination = termval;
}
return 0;
}
static size_t can_get_size(const struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
size_t size = 0;
if (priv->bittiming.bitrate) /* IFLA_CAN_BITTIMING */
size += nla_total_size(sizeof(struct can_bittiming));
if (priv->bittiming_const) /* IFLA_CAN_BITTIMING_CONST */
size += nla_total_size(sizeof(struct can_bittiming_const));
size += nla_total_size(sizeof(struct can_clock)); /* IFLA_CAN_CLOCK */
size += nla_total_size(sizeof(u32)); /* IFLA_CAN_STATE */
size += nla_total_size(sizeof(struct can_ctrlmode)); /* IFLA_CAN_CTRLMODE */
size += nla_total_size(sizeof(u32)); /* IFLA_CAN_RESTART_MS */
if (priv->do_get_berr_counter) /* IFLA_CAN_BERR_COUNTER */
size += nla_total_size(sizeof(struct can_berr_counter));
if (priv->data_bittiming.bitrate) /* IFLA_CAN_DATA_BITTIMING */
size += nla_total_size(sizeof(struct can_bittiming));
if (priv->data_bittiming_const) /* IFLA_CAN_DATA_BITTIMING_CONST */
size += nla_total_size(sizeof(struct can_bittiming_const));
if (priv->termination_const) {
size += nla_total_size(sizeof(priv->termination)); /* IFLA_CAN_TERMINATION */
size += nla_total_size(sizeof(*priv->termination_const) * /* IFLA_CAN_TERMINATION_CONST */
priv->termination_const_cnt);
}
if (priv->bitrate_const) /* IFLA_CAN_BITRATE_CONST */
size += nla_total_size(sizeof(*priv->bitrate_const) *
priv->bitrate_const_cnt);
if (priv->data_bitrate_const) /* IFLA_CAN_DATA_BITRATE_CONST */
size += nla_total_size(sizeof(*priv->data_bitrate_const) *
priv->data_bitrate_const_cnt);
size += sizeof(priv->bitrate_max); /* IFLA_CAN_BITRATE_MAX */
return size;
}
static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
struct can_ctrlmode cm = {.flags = priv->ctrlmode};
struct can_berr_counter bec;
enum can_state state = priv->state;
if (priv->do_get_state)
priv->do_get_state(dev, &state);
if ((priv->bittiming.bitrate &&
nla_put(skb, IFLA_CAN_BITTIMING,
sizeof(priv->bittiming), &priv->bittiming)) ||
(priv->bittiming_const &&
nla_put(skb, IFLA_CAN_BITTIMING_CONST,
sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
nla_put_u32(skb, IFLA_CAN_STATE, state) ||
nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
(priv->do_get_berr_counter &&
!priv->do_get_berr_counter(dev, &bec) &&
nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
(priv->data_bittiming.bitrate &&
nla_put(skb, IFLA_CAN_DATA_BITTIMING,
sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
(priv->data_bittiming_const &&
nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
sizeof(*priv->data_bittiming_const),
priv->data_bittiming_const)) ||
(priv->termination_const &&
(nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
nla_put(skb, IFLA_CAN_TERMINATION_CONST,
sizeof(*priv->termination_const) *
priv->termination_const_cnt,
priv->termination_const))) ||
(priv->bitrate_const &&
nla_put(skb, IFLA_CAN_BITRATE_CONST,
sizeof(*priv->bitrate_const) *
priv->bitrate_const_cnt,
priv->bitrate_const)) ||
(priv->data_bitrate_const &&
nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
sizeof(*priv->data_bitrate_const) *
priv->data_bitrate_const_cnt,
priv->data_bitrate_const)) ||
(nla_put(skb, IFLA_CAN_BITRATE_MAX,
sizeof(priv->bitrate_max),
&priv->bitrate_max))
)
return -EMSGSIZE;
return 0;
}
static size_t can_get_xstats_size(const struct net_device *dev)
{
return sizeof(struct can_device_stats);
}
static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
if (nla_put(skb, IFLA_INFO_XSTATS,
sizeof(priv->can_stats), &priv->can_stats))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int can_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
return -EOPNOTSUPP;
}
static void can_dellink(struct net_device *dev, struct list_head *head)
{
}
static struct rtnl_link_ops can_link_ops __read_mostly = {
.kind = "can",
.maxtype = IFLA_CAN_MAX,
.policy = can_policy,
.setup = can_setup,
.validate = can_validate,
.newlink = can_newlink,
.changelink = can_changelink,
.dellink = can_dellink,
.get_size = can_get_size,
.fill_info = can_fill_info,
.get_xstats_size = can_get_xstats_size,
.fill_xstats = can_fill_xstats,
};
/* Register the CAN network device */
int register_candev(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
/* 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;
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;
can_led_notifier_init();
err = rtnl_link_register(&can_link_ops);
if (!err)
pr_info(MOD_DESC "\n");
return err;
}
module_init(can_dev_init);
static __exit void can_dev_exit(void)
{
rtnl_link_unregister(&can_link_ops);
can_led_notifier_exit();
}
module_exit(can_dev_exit);
MODULE_ALIAS_RTNL_LINK("can");
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