/* * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix * Copyright (C) 2006 Andrey Volkov, Varma Electronics * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the version 2 of the GNU General Public License * as published by the Free Software Foundation * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/module.h>#include <linux/kernel.h>#include <linux/slab.h>#include <linux/netdevice.h>#include <linux/if_arp.h>#include <linux/can.h>#include <linux/can/dev.h>#include <linux/can/netlink.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 */ /* * 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_spt(const struct can_bittiming_const *btc, int sampl_pt, int tseg, int *tseg1, int *tseg2){ *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000; if (*tseg2 < btc->tseg2_min) *tseg2 = btc->tseg2_min; if (*tseg2 > btc->tseg2_max) *tseg2 = btc->tseg2_max; *tseg1 = tseg - *tseg2; if (*tseg1 > btc->tseg1_max) { *tseg1 = btc->tseg1_max; *tseg2 = tseg - *tseg1; } return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);} static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt){ struct can_priv *priv = netdev_priv(dev); const struct can_bittiming_const *btc = priv->bittiming_const; long rate, best_rate = 0; long best_error = 1000000000, error = 0; int best_tseg = 0, best_brp = 0, brp = 0; int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0; int spt_error = 1000, spt = 0, sampl_pt; u64 v64; if (!priv->bittiming_const) return -ENOTSUPP; /* Use CIA recommended sample points */ if (bt->sample_point) { sampl_pt = bt->sample_point; } else { if (bt->bitrate > 800000) sampl_pt = 750; else if (bt->bitrate > 500000) sampl_pt = 800; else sampl_pt = 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 = 1 + tseg / 2; /* Compute all possible tseg choices (tseg=tseg1+tseg2) */ brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2; /* chose 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; rate = priv->clock.freq / (brp * tsegall); error = bt->bitrate - rate; /* tseg brp biterror */ if (error < 0) error = -error; if (error > best_error) continue; best_error = error; if (error == 0) { spt = can_update_spt(btc, sampl_pt, tseg / 2, &tseg1, &tseg2); error = sampl_pt - spt; if (error < 0) error = -error; if (error > spt_error) continue; spt_error = error; } best_tseg = tseg / 2; best_brp = brp; best_rate = rate; if (error == 0) break; } if (best_error) { /* Error in one-tenth of a percent */ error = (best_error * 1000) / bt->bitrate; if (error > CAN_CALC_MAX_ERROR) { netdev_err(dev, "bitrate error %ld.%ld%% too high\n", error / 10, error % 10); return -EDOM; } else { netdev_warn(dev, "bitrate error %ld.%ld%%\n", error / 10, error % 10); } } /* real sample point */ bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg, &tseg1, &tseg2); v64 = (u64)best_brp * 1000000000UL; 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 bit-rate */ bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1)); return 0;}#else /* !CONFIG_CAN_CALC_BITTIMING */static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt){ 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){ struct can_priv *priv = netdev_priv(dev); const struct can_bittiming_const *btc = priv->bittiming_const; int tseg1, alltseg; u64 brp64; if (!priv->bittiming_const) return -ENOTSUPP; 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;} static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt){ struct can_priv *priv = netdev_priv(dev); int err; /* Check if the CAN device has bit-timing parameters */ if (priv->bittiming_const) { /* Non-expert mode? Check if the bitrate has been pre-defined */ if (!bt->tq) /* Determine bit-timing parameters */ err = can_calc_bittiming(dev, bt); else /* Check bit-timing params and calculate proper brp */ err = can_fixup_bittiming(dev, bt); if (err) return err; } return 0;} /* * Local echo of CAN messages * * CAN network devices *should* support a local echo functionality * (see Documentation/networking/can.txt). 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) { kfree_skb(skb); return; } if (!priv->echo_skb[idx]) { struct sock *srcsk = skb->sk; if (atomic_read(&skb->users) != 1) { struct sk_buff *old_skb = skb; skb = skb_clone(old_skb, GFP_ATOMIC); kfree_skb(old_skb); if (!skb) return; } else skb_orphan(skb); skb->sk = srcsk; /* make settings for echo to reduce code in irq context */ skb->protocol = htons(ETH_P_CAN); 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); /* * 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 can_priv *priv = netdev_priv(dev); BUG_ON(idx >= priv->echo_skb_max); if (priv->echo_skb[idx]) { struct sk_buff *skb = priv->echo_skb[idx]; struct can_frame *cf = (struct can_frame *)skb->data; u8 dlc = cf->can_dlc; netif_rx(priv->echo_skb[idx]); priv->echo_skb[idx] = NULL; return dlc; } return 0;}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]) { kfree_skb(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(unsigned long data){ struct net_device *dev = (struct net_device *)data; 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 == NULL) { err = -ENOMEM; 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);} 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; /* Runs as soon as possible in the timer context */ mod_timer(&priv->restart_timer, jiffies); 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_dbg(dev, "bus-off\n"); netif_carrier_off(dev); priv->can_stats.bus_off++; if (priv->restart_ms) mod_timer(&priv->restart_timer, jiffies + (priv->restart_ms * HZ) / 1000);}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)Lines 1–500 of 816. Load more
/* * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix * Copyright (C) 2006 Andrey Volkov, Varma Electronics * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the version 2 of the GNU General Public License * as published by the Free Software Foundation * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/netdevice.h> #include <linux/if_arp.h> #include <linux/can.h> #include <linux/can/dev.h> #include <linux/can/netlink.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 */ /* * 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_spt(const struct can_bittiming_const *btc, int sampl_pt, int tseg, int *tseg1, int *tseg2) { *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000; if (*tseg2 < btc->tseg2_min) *tseg2 = btc->tseg2_min; if (*tseg2 > btc->tseg2_max) *tseg2 = btc->tseg2_max; *tseg1 = tseg - *tseg2; if (*tseg1 > btc->tseg1_max) { *tseg1 = btc->tseg1_max; *tseg2 = tseg - *tseg1; } return 1000 * (tseg + 1 - *tseg2) / (tseg + 1); } static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt) { struct can_priv *priv = netdev_priv(dev); const struct can_bittiming_const *btc = priv->bittiming_const; long rate, best_rate = 0; long best_error = 1000000000, error = 0; int best_tseg = 0, best_brp = 0, brp = 0; int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0; int spt_error = 1000, spt = 0, sampl_pt; u64 v64; if (!priv->bittiming_const) return -ENOTSUPP; /* Use CIA recommended sample points */ if (bt->sample_point) { sampl_pt = bt->sample_point; } else { if (bt->bitrate > 800000) sampl_pt = 750; else if (bt->bitrate > 500000) sampl_pt = 800; else sampl_pt = 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 = 1 + tseg / 2; /* Compute all possible tseg choices (tseg=tseg1+tseg2) */ brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2; /* chose 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; rate = priv->clock.freq / (brp * tsegall); error = bt->bitrate - rate; /* tseg brp biterror */ if (error < 0) error = -error; if (error > best_error) continue; best_error = error; if (error == 0) { spt = can_update_spt(btc, sampl_pt, tseg / 2, &tseg1, &tseg2); error = sampl_pt - spt; if (error < 0) error = -error; if (error > spt_error) continue; spt_error = error; } best_tseg = tseg / 2; best_brp = brp; best_rate = rate; if (error == 0) break; } if (best_error) { /* Error in one-tenth of a percent */ error = (best_error * 1000) / bt->bitrate; if (error > CAN_CALC_MAX_ERROR) { netdev_err(dev, "bitrate error %ld.%ld%% too high\n", error / 10, error % 10); return -EDOM; } else { netdev_warn(dev, "bitrate error %ld.%ld%%\n", error / 10, error % 10); } } /* real sample point */ bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg, &tseg1, &tseg2); v64 = (u64)best_brp * 1000000000UL; 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 bit-rate */ bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1)); return 0; } #else /* !CONFIG_CAN_CALC_BITTIMING */ static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt) { 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) { struct can_priv *priv = netdev_priv(dev); const struct can_bittiming_const *btc = priv->bittiming_const; int tseg1, alltseg; u64 brp64; if (!priv->bittiming_const) return -ENOTSUPP; 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; } static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt) { struct can_priv *priv = netdev_priv(dev); int err; /* Check if the CAN device has bit-timing parameters */ if (priv->bittiming_const) { /* Non-expert mode? Check if the bitrate has been pre-defined */ if (!bt->tq) /* Determine bit-timing parameters */ err = can_calc_bittiming(dev, bt); else /* Check bit-timing params and calculate proper brp */ err = can_fixup_bittiming(dev, bt); if (err) return err; } return 0; } /* * Local echo of CAN messages * * CAN network devices *should* support a local echo functionality * (see Documentation/networking/can.txt). 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) { kfree_skb(skb); return; } if (!priv->echo_skb[idx]) { struct sock *srcsk = skb->sk; if (atomic_read(&skb->users) != 1) { struct sk_buff *old_skb = skb; skb = skb_clone(old_skb, GFP_ATOMIC); kfree_skb(old_skb); if (!skb) return; } else skb_orphan(skb); skb->sk = srcsk; /* make settings for echo to reduce code in irq context */ skb->protocol = htons(ETH_P_CAN); 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); /* * 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 can_priv *priv = netdev_priv(dev); BUG_ON(idx >= priv->echo_skb_max); if (priv->echo_skb[idx]) { struct sk_buff *skb = priv->echo_skb[idx]; struct can_frame *cf = (struct can_frame *)skb->data; u8 dlc = cf->can_dlc; netif_rx(priv->echo_skb[idx]); priv->echo_skb[idx] = NULL; return dlc; } return 0; } 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]) { kfree_skb(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(unsigned long data) { struct net_device *dev = (struct net_device *)data; 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 == NULL) { err = -ENOMEM; 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); } 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; /* Runs as soon as possible in the timer context */ mod_timer(&priv->restart_timer, jiffies); 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_dbg(dev, "bus-off\n"); netif_carrier_off(dev); priv->can_stats.bus_off++; if (priv->restart_ms) mod_timer(&priv->restart_timer, jiffies + (priv->restart_ms * HZ) / 1000); } 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)