// 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/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 protectLines 1–500 of 1300. Load more
// 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/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