/* * CAN bus driver for Bosch C_CAN controller * * Copyright (C) 2010 ST Microelectronics * Bhupesh Sharma * * Borrowed heavily from the C_CAN driver originally written by: * Copyright (C) 2007 * - Sascha Hauer, Marc Kleine-Budde, Pengutronix * - Simon Kallweit, intefo AG * * TX and RX NAPI implementation has been borrowed from at91 CAN driver * written by: * Copyright * (C) 2007 by Hans J. Koch * (C) 2008, 2009 by Marc Kleine-Budde * * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B. * Bosch C_CAN user manual can be obtained from: * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/ * users_manual_c_can.pdf * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "c_can.h" /* control register */ #define CONTROL_TEST BIT(7) #define CONTROL_CCE BIT(6) #define CONTROL_DISABLE_AR BIT(5) #define CONTROL_ENABLE_AR (0 << 5) #define CONTROL_EIE BIT(3) #define CONTROL_SIE BIT(2) #define CONTROL_IE BIT(1) #define CONTROL_INIT BIT(0) /* test register */ #define TEST_RX BIT(7) #define TEST_TX1 BIT(6) #define TEST_TX2 BIT(5) #define TEST_LBACK BIT(4) #define TEST_SILENT BIT(3) #define TEST_BASIC BIT(2) /* status register */ #define STATUS_BOFF BIT(7) #define STATUS_EWARN BIT(6) #define STATUS_EPASS BIT(5) #define STATUS_RXOK BIT(4) #define STATUS_TXOK BIT(3) /* error counter register */ #define ERR_CNT_TEC_MASK 0xff #define ERR_CNT_TEC_SHIFT 0 #define ERR_CNT_REC_SHIFT 8 #define ERR_CNT_REC_MASK (0x7f << ERR_CNT_REC_SHIFT) #define ERR_CNT_RP_SHIFT 15 #define ERR_CNT_RP_MASK (0x1 << ERR_CNT_RP_SHIFT) /* bit-timing register */ #define BTR_BRP_MASK 0x3f #define BTR_BRP_SHIFT 0 #define BTR_SJW_SHIFT 6 #define BTR_SJW_MASK (0x3 << BTR_SJW_SHIFT) #define BTR_TSEG1_SHIFT 8 #define BTR_TSEG1_MASK (0xf << BTR_TSEG1_SHIFT) #define BTR_TSEG2_SHIFT 12 #define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT) /* brp extension register */ #define BRP_EXT_BRPE_MASK 0x0f #define BRP_EXT_BRPE_SHIFT 0 /* IFx command request */ #define IF_COMR_BUSY BIT(15) /* IFx command mask */ #define IF_COMM_WR BIT(7) #define IF_COMM_MASK BIT(6) #define IF_COMM_ARB BIT(5) #define IF_COMM_CONTROL BIT(4) #define IF_COMM_CLR_INT_PND BIT(3) #define IF_COMM_TXRQST BIT(2) #define IF_COMM_DATAA BIT(1) #define IF_COMM_DATAB BIT(0) #define IF_COMM_ALL (IF_COMM_MASK | IF_COMM_ARB | \ IF_COMM_CONTROL | IF_COMM_TXRQST | \ IF_COMM_DATAA | IF_COMM_DATAB) /* IFx arbitration */ #define IF_ARB_MSGVAL BIT(15) #define IF_ARB_MSGXTD BIT(14) #define IF_ARB_TRANSMIT BIT(13) /* IFx message control */ #define IF_MCONT_NEWDAT BIT(15) #define IF_MCONT_MSGLST BIT(14) #define IF_MCONT_CLR_MSGLST (0 << 14) #define IF_MCONT_INTPND BIT(13) #define IF_MCONT_UMASK BIT(12) #define IF_MCONT_TXIE BIT(11) #define IF_MCONT_RXIE BIT(10) #define IF_MCONT_RMTEN BIT(9) #define IF_MCONT_TXRQST BIT(8) #define IF_MCONT_EOB BIT(7) #define IF_MCONT_DLC_MASK 0xf /* * IFx register masks: * allow easy operation on 16-bit registers when the * argument is 32-bit instead */ #define IFX_WRITE_LOW_16BIT(x) ((x) & 0xFFFF) #define IFX_WRITE_HIGH_16BIT(x) (((x) & 0xFFFF0000) >> 16) /* message object split */ #define C_CAN_NO_OF_OBJECTS 32 #define C_CAN_MSG_OBJ_RX_NUM 16 #define C_CAN_MSG_OBJ_TX_NUM 16 #define C_CAN_MSG_OBJ_RX_FIRST 1 #define C_CAN_MSG_OBJ_RX_LAST (C_CAN_MSG_OBJ_RX_FIRST + \ C_CAN_MSG_OBJ_RX_NUM - 1) #define C_CAN_MSG_OBJ_TX_FIRST (C_CAN_MSG_OBJ_RX_LAST + 1) #define C_CAN_MSG_OBJ_TX_LAST (C_CAN_MSG_OBJ_TX_FIRST + \ C_CAN_MSG_OBJ_TX_NUM - 1) #define C_CAN_MSG_OBJ_RX_SPLIT 9 #define C_CAN_MSG_RX_LOW_LAST (C_CAN_MSG_OBJ_RX_SPLIT - 1) #define C_CAN_NEXT_MSG_OBJ_MASK (C_CAN_MSG_OBJ_TX_NUM - 1) #define RECEIVE_OBJECT_BITS 0x0000ffff /* status interrupt */ #define STATUS_INTERRUPT 0x8000 /* global interrupt masks */ #define ENABLE_ALL_INTERRUPTS 1 #define DISABLE_ALL_INTERRUPTS 0 /* minimum timeout for checking BUSY status */ #define MIN_TIMEOUT_VALUE 6 /* napi related */ #define C_CAN_NAPI_WEIGHT C_CAN_MSG_OBJ_RX_NUM /* c_can lec values */ enum c_can_lec_type { LEC_NO_ERROR = 0, LEC_STUFF_ERROR, LEC_FORM_ERROR, LEC_ACK_ERROR, LEC_BIT1_ERROR, LEC_BIT0_ERROR, LEC_CRC_ERROR, LEC_UNUSED, }; /* * c_can error types: * Bus errors (BUS_OFF, ERROR_WARNING, ERROR_PASSIVE) are supported */ enum c_can_bus_error_types { C_CAN_NO_ERROR = 0, C_CAN_BUS_OFF, C_CAN_ERROR_WARNING, C_CAN_ERROR_PASSIVE, }; static struct can_bittiming_const c_can_bittiming_const = { .name = KBUILD_MODNAME, .tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1 */ .tseg1_max = 16, .tseg2_min = 1, /* Time segment 2 = phase_seg2 */ .tseg2_max = 8, .sjw_max = 4, .brp_min = 1, .brp_max = 1024, /* 6-bit BRP field + 4-bit BRPE field*/ .brp_inc = 1, }; static inline int get_tx_next_msg_obj(const struct c_can_priv *priv) { return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) + C_CAN_MSG_OBJ_TX_FIRST; } static inline int get_tx_echo_msg_obj(const struct c_can_priv *priv) { return (priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) + C_CAN_MSG_OBJ_TX_FIRST; } static u32 c_can_read_reg32(struct c_can_priv *priv, void *reg) { u32 val = priv->read_reg(priv, reg); val |= ((u32) priv->read_reg(priv, reg + 2)) << 16; return val; } static void c_can_enable_all_interrupts(struct c_can_priv *priv, int enable) { unsigned int cntrl_save = priv->read_reg(priv, &priv->regs->control); if (enable) cntrl_save |= (CONTROL_SIE | CONTROL_EIE | CONTROL_IE); else cntrl_save &= ~(CONTROL_EIE | CONTROL_IE | CONTROL_SIE); priv->write_reg(priv, &priv->regs->control, cntrl_save); } static inline int c_can_msg_obj_is_busy(struct c_can_priv *priv, int iface) { int count = MIN_TIMEOUT_VALUE; while (count && priv->read_reg(priv, &priv->regs->ifregs[iface].com_req) & IF_COMR_BUSY) { count--; udelay(1); } if (!count) return 1; return 0; } static inline void c_can_object_get(struct net_device *dev, int iface, int objno, int mask) { struct c_can_priv *priv = netdev_priv(dev); /* * As per specs, after writting the message object number in the * IF command request register the transfer b/w interface * register and message RAM must be complete in 6 CAN-CLK * period. */ priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask, IFX_WRITE_LOW_16BIT(mask)); priv->write_reg(priv, &priv->regs->ifregs[iface].com_req, IFX_WRITE_LOW_16BIT(objno)); if (c_can_msg_obj_is_busy(priv, iface)) netdev_err(dev, "timed out in object get\n"); } static inline void c_can_object_put(struct net_device *dev, int iface, int objno, int mask) { struct c_can_priv *priv = netdev_priv(dev); /* * As per specs, after writting the message object number in the * IF command request register the transfer b/w interface * register and message RAM must be complete in 6 CAN-CLK * period. */ priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask, (IF_COMM_WR | IFX_WRITE_LOW_16BIT(mask))); priv->write_reg(priv, &priv->regs->ifregs[iface].com_req, IFX_WRITE_LOW_16BIT(objno)); if (c_can_msg_obj_is_busy(priv, iface)) netdev_err(dev, "timed out in object put\n"); } static void c_can_write_msg_object(struct net_device *dev, int iface, struct can_frame *frame, int objno) { int i; u16 flags = 0; unsigned int id; struct c_can_priv *priv = netdev_priv(dev); if (!(frame->can_id & CAN_RTR_FLAG)) flags |= IF_ARB_TRANSMIT; if (frame->can_id & CAN_EFF_FLAG) { id = frame->can_id & CAN_EFF_MASK; flags |= IF_ARB_MSGXTD; } else id = ((frame->can_id & CAN_SFF_MASK) << 18); flags |= IF_ARB_MSGVAL; priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, IFX_WRITE_LOW_16BIT(id)); priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, flags | IFX_WRITE_HIGH_16BIT(id)); for (i = 0; i < frame->can_dlc; i += 2) { priv->write_reg(priv, &priv->regs->ifregs[iface].data[i / 2], frame->data[i] | (frame->data[i + 1] << 8)); } /* enable interrupt for this message object */ priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, IF_MCONT_TXIE | IF_MCONT_TXRQST | IF_MCONT_EOB | frame->can_dlc); c_can_object_put(dev, iface, objno, IF_COMM_ALL); } static inline void c_can_mark_rx_msg_obj(struct net_device *dev, int iface, int ctrl_mask, int obj) { struct c_can_priv *priv = netdev_priv(dev); priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, ctrl_mask & ~(IF_MCONT_MSGLST | IF_MCONT_INTPND)); c_can_object_put(dev, iface, obj, IF_COMM_CONTROL); } static inline void c_can_activate_all_lower_rx_msg_obj(struct net_device *dev, int iface, int ctrl_mask) { int i; struct c_can_priv *priv = netdev_priv(dev); for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_MSG_RX_LOW_LAST; i++) { priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, ctrl_mask & ~(IF_MCONT_MSGLST | IF_MCONT_INTPND | IF_MCONT_NEWDAT)); c_can_object_put(dev, iface, i, IF_COMM_CONTROL); } } static inline void c_can_activate_rx_msg_obj(struct net_device *dev, int iface, int ctrl_mask, int obj) { struct c_can_priv *priv = netdev_priv(dev); priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, ctrl_mask & ~(IF_MCONT_MSGLST | IF_MCONT_INTPND | IF_MCONT_NEWDAT)); c_can_object_put(dev, iface, obj, IF_COMM_CONTROL); } static void c_can_handle_lost_msg_obj(struct net_device *dev, int iface, int objno) { struct c_can_priv *priv = netdev_priv(dev); struct net_device_stats *stats = &dev->stats; struct sk_buff *skb; struct can_frame *frame; netdev_err(dev, "msg lost in buffer %d\n", objno); c_can_object_get(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST); priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, IF_MCONT_CLR_MSGLST); c_can_object_put(dev, 0, objno, IF_COMM_CONTROL); /* create an error msg */ skb = alloc_can_err_skb(dev, &frame); if (unlikely(!skb)) return; frame->can_id |= CAN_ERR_CRTL; frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW; stats->rx_errors++; stats->rx_over_errors++; netif_receive_skb(skb); } static int c_can_read_msg_object(struct net_device *dev, int iface, int ctrl) { u16 flags, data; int i; unsigned int val; struct c_can_priv *priv = netdev_priv(dev); struct net_device_stats *stats = &dev->stats; struct sk_buff *skb; struct can_frame *frame; skb = alloc_can_skb(dev, &frame); if (!skb) { stats->rx_dropped++; return -ENOMEM; } frame->can_dlc = get_can_dlc(ctrl & 0x0F); flags = priv->read_reg(priv, &priv->regs->ifregs[iface].arb2); val = priv->read_reg(priv, &priv->regs->ifregs[iface].arb1) | (flags << 16); if (flags & IF_ARB_MSGXTD) frame->can_id = (val & CAN_EFF_MASK) | CAN_EFF_FLAG; else frame->can_id = (val >> 18) & CAN_SFF_MASK; if (flags & IF_ARB_TRANSMIT) frame->can_id |= CAN_RTR_FLAG; else { for (i = 0; i < frame->can_dlc; i += 2) { data = priv->read_reg(priv, &priv->regs->ifregs[iface].data[i / 2]); frame->data[i] = data; frame->data[i + 1] = data >> 8; } } netif_receive_skb(skb); stats->rx_packets++; stats->rx_bytes += frame->can_dlc; return 0; } static void c_can_setup_receive_object(struct net_device *dev, int iface, int objno, unsigned int mask, unsigned int id, unsigned int mcont) { struct c_can_priv *priv = netdev_priv(dev); priv->write_reg(priv, &priv->regs->ifregs[iface].mask1, IFX_WRITE_LOW_16BIT(mask)); priv->write_reg(priv, &priv->regs->ifregs[iface].mask2, IFX_WRITE_HIGH_16BIT(mask)); priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, IFX_WRITE_LOW_16BIT(id)); priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, (IF_ARB_MSGVAL | IFX_WRITE_HIGH_16BIT(id))); priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, mcont); c_can_object_put(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST); netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, c_can_read_reg32(priv, &priv->regs->msgval1)); } static void c_can_inval_msg_object(struct net_device *dev, int iface, int objno) { struct c_can_priv *priv = netdev_priv(dev); priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, 0); priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, 0); priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 0); c_can_object_put(dev, iface, objno, IF_COMM_ARB | IF_COMM_CONTROL); netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, c_can_read_reg32(priv, &priv->regs->msgval1)); } static inline int c_can_is_next_tx_obj_busy(struct c_can_priv *priv, int objno) { int val = c_can_read_reg32(priv, &priv->regs->txrqst1); /* * as transmission request register's bit n-1 corresponds to * message object n, we need to handle the same properly. */ if (val & (1 << (objno - 1))) return 1; return 0; } static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, struct net_device *dev) { u32 msg_obj_no; struct c_can_priv *priv = netdev_priv(dev); struct can_frame *frame = (struct can_frame *)skb->data; if (can_dropped_invalid_skb(dev, skb)) return NETDEV_TX_OK; msg_obj_no = get_tx_next_msg_obj(priv); /* prepare message object for transmission */ c_can_write_msg_object(dev, 0, frame, msg_obj_no); can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); /* * we have to stop the queue in case of a wrap around or * if the next TX message object is still in use */ priv->tx_next++; if (c_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) || (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0) netif_stop_queue(dev); return NETDEV_TX_OK; } static int c_can_set_bittiming(struct net_device *dev) { unsigned int reg_btr, reg_brpe, ctrl_save; u8 brp, brpe, sjw, tseg1, tseg2; u32 ten_bit_brp; struct c_can_priv *priv = netdev_priv(dev); const struct can_bittiming *bt = &priv->can.bittiming; /* c_can provides a 6-bit brp and 4-bit brpe fields */ ten_bit_brp = bt->brp - 1; brp = ten_bit_brp & BTR_BRP_MASK; brpe = ten_bit_brp >> 6; sjw = bt->sjw - 1; tseg1 = bt->prop_seg + bt->phase_seg1 - 1; tseg2 = bt->phase_seg2 - 1; reg_btr = brp | (sjw << BTR_SJW_SHIFT) | (tseg1 << BTR_TSEG1_SHIFT) | (tseg2 << BTR_TSEG2_SHIFT); reg_brpe = brpe & BRP_EXT_BRPE_MASK; netdev_info(dev, "setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe); ctrl_save = priv->read_reg(priv, &priv->regs->control); priv->write_reg(priv, &priv->regs->control, ctrl_save | CONTROL_CCE | CONTROL_INIT); priv->write_reg(priv, &priv->regs->btr, reg_btr); priv->write_reg(priv, &priv->regs->brp_ext, reg_brpe); priv->write_reg(priv, &priv->regs->control, ctrl_save); return 0; } /* * Configure C_CAN message objects for Tx and Rx purposes: * C_CAN provides a total of 32 message objects that can be configured * either for Tx or Rx purposes. Here the first 16 message objects are used as * a reception FIFO. The end of reception FIFO is signified by the EoB bit * being SET. The remaining 16 message objects are kept aside for Tx purposes. * See user guide document for further details on configuring message * objects. */ static void c_can_configure_msg_objects(struct net_device *dev) { int i; /* first invalidate all message objects */ for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++) c_can_inval_msg_object(dev, 0, i); /* setup receive message objects */ for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++) c_can_setup_receive_object(dev, 0, i, 0, 0, (IF_MCONT_RXIE | IF_MCONT_UMASK) & ~IF_MCONT_EOB); c_can_setup_receive_object(dev, 0, C_CAN_MSG_OBJ_RX_LAST, 0, 0, IF_MCONT_EOB | IF_MCONT_RXIE | IF_MCONT_UMASK); } /* * Configure C_CAN chip: * - enable/disable auto-retransmission * - set operating mode * - configure message objects */ static void c_can_chip_config(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT) /* disable automatic retransmission */ priv->write_reg(priv, &priv->regs->control, CONTROL_DISABLE_AR); else /* enable automatic retransmission */ priv->write_reg(priv, &priv->regs->control, CONTROL_ENABLE_AR); if (priv->can.ctrlmode & (CAN_CTRLMODE_LISTENONLY & CAN_CTRLMODE_LOOPBACK)) { /* loopback + silent mode : useful for hot self-test */ priv->write_reg(priv, &priv->regs->control, CONTROL_EIE | CONTROL_SIE | CONTROL_IE | CONTROL_TEST); priv->write_reg(priv, &priv->regs->test, TEST_LBACK | TEST_SILENT); } else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) { /* loopback mode : useful for self-test function */ priv->write_reg(priv, &priv->regs->control, CONTROL_EIE | CONTROL_SIE | CONTROL_IE | CONTROL_TEST); priv->write_reg(priv, &priv->regs->test, TEST_LBACK); } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) { /* silent mode : bus-monitoring mode */ priv->write_reg(priv, &priv->regs->control, CONTROL_EIE | CONTROL_SIE | CONTROL_IE | CONTROL_TEST); priv->write_reg(priv, &priv->regs->test, TEST_SILENT); } else /* normal mode*/ priv->write_reg(priv, &priv->regs->control, CONTROL_EIE | CONTROL_SIE | CONTROL_IE); /* configure message objects */ c_can_configure_msg_objects(dev); /* set a `lec` value so that we can check for updates later */ priv->write_reg(priv, &priv->regs->status, LEC_UNUSED); /* set bittiming params */ c_can_set_bittiming(dev); } static void c_can_start(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); /* basic c_can configuration */ c_can_chip_config(dev); priv->can.state = CAN_STATE_ERROR_ACTIVE; /* reset tx helper pointers */ priv->tx_next = priv->tx_echo = 0; /* enable status change, error and module interrupts */ c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS); } static void c_can_stop(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); /* disable all interrupts */ c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); /* set the state as STOPPED */ priv->can.state = CAN_STATE_STOPPED; } static int c_can_set_mode(struct net_device *dev, enum can_mode mode) { switch (mode) { case CAN_MODE_START: c_can_start(dev); netif_wake_queue(dev); break; default: return -EOPNOTSUPP; } return 0; } static int c_can_get_berr_counter(const struct net_device *dev, struct can_berr_counter *bec) { unsigned int reg_err_counter; struct c_can_priv *priv = netdev_priv(dev); reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt); bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >> ERR_CNT_REC_SHIFT; bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK; return 0; } /* * theory of operation: * * priv->tx_echo holds the number of the oldest can_frame put for * transmission into the hardware, but not yet ACKed by the CAN tx * complete IRQ. * * We iterate from priv->tx_echo to priv->tx_next and check if the * packet has been transmitted, echo it back to the CAN framework. * If we discover a not yet transmitted package, stop looking for more. */ static void c_can_do_tx(struct net_device *dev) { u32 val; u32 msg_obj_no; struct c_can_priv *priv = netdev_priv(dev); struct net_device_stats *stats = &dev->stats; for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) { msg_obj_no = get_tx_echo_msg_obj(priv); c_can_inval_msg_object(dev, 0, msg_obj_no); val = c_can_read_reg32(priv, &priv->regs->txrqst1); if (!(val & (1 << msg_obj_no))) { can_get_echo_skb(dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); stats->tx_bytes += priv->read_reg(priv, &priv->regs->ifregs[0].msg_cntrl) & IF_MCONT_DLC_MASK; stats->tx_packets++; } } /* restart queue if wrap-up or if queue stalled on last pkt */ if (((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) != 0) || ((priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) == 0)) netif_wake_queue(dev); } /* * theory of operation: * * c_can core saves a received CAN message into the first free message * object it finds free (starting with the lowest). Bits NEWDAT and * INTPND are set for this message object indicating that a new message * has arrived. To work-around this issue, we keep two groups of message * objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT. * * To ensure in-order frame reception we use the following * approach while re-activating a message object to receive further * frames: * - if the current message object number is lower than * C_CAN_MSG_RX_LOW_LAST, do not clear the NEWDAT bit while clearing * the INTPND bit. * - if the current message object number is equal to * C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of all lower * receive message objects. * - if the current message object number is greater than * C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of * only this message object. */ static int c_can_do_rx_poll(struct net_device *dev, int quota) { u32 num_rx_pkts = 0; unsigned int msg_obj, msg_ctrl_save; struct c_can_priv *priv = netdev_priv(dev); u32 val = c_can_read_reg32(priv, &priv->regs->intpnd1); for (msg_obj = C_CAN_MSG_OBJ_RX_FIRST; msg_obj <= C_CAN_MSG_OBJ_RX_LAST && quota > 0; val = c_can_read_reg32(priv, &priv->regs->intpnd1), msg_obj++) { /* * as interrupt pending register's bit n-1 corresponds to * message object n, we need to handle the same properly. */ if (val & (1 << (msg_obj - 1))) { c_can_object_get(dev, 0, msg_obj, IF_COMM_ALL & ~IF_COMM_TXRQST); msg_ctrl_save = priv->read_reg(priv, &priv->regs->ifregs[0].msg_cntrl); if (msg_ctrl_save & IF_MCONT_EOB) return num_rx_pkts; if (msg_ctrl_save & IF_MCONT_MSGLST) { c_can_handle_lost_msg_obj(dev, 0, msg_obj); num_rx_pkts++; quota--; continue; } if (!(msg_ctrl_save & IF_MCONT_NEWDAT)) continue; /* read the data from the message object */ c_can_read_msg_object(dev, 0, msg_ctrl_save); if (msg_obj < C_CAN_MSG_RX_LOW_LAST) c_can_mark_rx_msg_obj(dev, 0, msg_ctrl_save, msg_obj); else if (msg_obj > C_CAN_MSG_RX_LOW_LAST) /* activate this msg obj */ c_can_activate_rx_msg_obj(dev, 0, msg_ctrl_save, msg_obj); else if (msg_obj == C_CAN_MSG_RX_LOW_LAST) /* activate all lower message objects */ c_can_activate_all_lower_rx_msg_obj(dev, 0, msg_ctrl_save); num_rx_pkts++; quota--; } } return num_rx_pkts; } static inline int c_can_has_and_handle_berr(struct c_can_priv *priv) { return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) && (priv->current_status & LEC_UNUSED); } static int c_can_handle_state_change(struct net_device *dev, enum c_can_bus_error_types error_type) { unsigned int reg_err_counter; unsigned int rx_err_passive; struct c_can_priv *priv = netdev_priv(dev); struct net_device_stats *stats = &dev->stats; struct can_frame *cf; struct sk_buff *skb; struct can_berr_counter bec; /* propogate the error condition to the CAN stack */ skb = alloc_can_err_skb(dev, &cf); if (unlikely(!skb)) return 0; c_can_get_berr_counter(dev, &bec); reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt); rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >> ERR_CNT_RP_SHIFT; switch (error_type) { case C_CAN_ERROR_WARNING: /* error warning state */ priv->can.can_stats.error_warning++; priv->can.state = CAN_STATE_ERROR_WARNING; cf->can_id |= CAN_ERR_CRTL; cf->data[1] = (bec.txerr > bec.rxerr) ? CAN_ERR_CRTL_TX_WARNING : CAN_ERR_CRTL_RX_WARNING; cf->data[6] = bec.txerr; cf->data[7] = bec.rxerr; break; case C_CAN_ERROR_PASSIVE: /* error passive state */ priv->can.can_stats.error_passive++; priv->can.state = CAN_STATE_ERROR_PASSIVE; cf->can_id |= CAN_ERR_CRTL; if (rx_err_passive) cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE; if (bec.txerr > 127) cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE; cf->data[6] = bec.txerr; cf->data[7] = bec.rxerr; break; case C_CAN_BUS_OFF: /* bus-off state */ priv->can.state = CAN_STATE_BUS_OFF; cf->can_id |= CAN_ERR_BUSOFF; /* * disable all interrupts in bus-off mode to ensure that * the CPU is not hogged down */ c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); can_bus_off(dev); break; default: break; } netif_receive_skb(skb); stats->rx_packets++; stats->rx_bytes += cf->can_dlc; return 1; } static int c_can_handle_bus_err(struct net_device *dev, enum c_can_lec_type lec_type) { struct c_can_priv *priv = netdev_priv(dev); struct net_device_stats *stats = &dev->stats; struct can_frame *cf; struct sk_buff *skb; /* * early exit if no lec update or no error. * no lec update means that no CAN bus event has been detected * since CPU wrote 0x7 value to status reg. */ if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR) return 0; /* propogate the error condition to the CAN stack */ skb = alloc_can_err_skb(dev, &cf); if (unlikely(!skb)) return 0; /* * check for 'last error code' which tells us the * type of the last error to occur on the CAN bus */ /* common for all type of bus errors */ priv->can.can_stats.bus_error++; stats->rx_errors++; cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; cf->data[2] |= CAN_ERR_PROT_UNSPEC; switch (lec_type) { case LEC_STUFF_ERROR: netdev_dbg(dev, "stuff error\n"); cf->data[2] |= CAN_ERR_PROT_STUFF; break; case LEC_FORM_ERROR: netdev_dbg(dev, "form error\n"); cf->data[2] |= CAN_ERR_PROT_FORM; break; case LEC_ACK_ERROR: netdev_dbg(dev, "ack error\n"); cf->data[2] |= (CAN_ERR_PROT_LOC_ACK | CAN_ERR_PROT_LOC_ACK_DEL); break; case LEC_BIT1_ERROR: netdev_dbg(dev, "bit1 error\n"); cf->data[2] |= CAN_ERR_PROT_BIT1; break; case LEC_BIT0_ERROR: netdev_dbg(dev, "bit0 error\n"); cf->data[2] |= CAN_ERR_PROT_BIT0; break; case LEC_CRC_ERROR: netdev_dbg(dev, "CRC error\n"); cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ | CAN_ERR_PROT_LOC_CRC_DEL); break; default: break; } /* set a `lec` value so that we can check for updates later */ priv->write_reg(priv, &priv->regs->status, LEC_UNUSED); netif_receive_skb(skb); stats->rx_packets++; stats->rx_bytes += cf->can_dlc; return 1; } static int c_can_poll(struct napi_struct *napi, int quota) { u16 irqstatus; int lec_type = 0; int work_done = 0; struct net_device *dev = napi->dev; struct c_can_priv *priv = netdev_priv(dev); irqstatus = priv->read_reg(priv, &priv->regs->interrupt); if (!irqstatus) goto end; /* status events have the highest priority */ if (irqstatus == STATUS_INTERRUPT) { priv->current_status = priv->read_reg(priv, &priv->regs->status); /* handle Tx/Rx events */ if (priv->current_status & STATUS_TXOK) priv->write_reg(priv, &priv->regs->status, priv->current_status & ~STATUS_TXOK); if (priv->current_status & STATUS_RXOK) priv->write_reg(priv, &priv->regs->status, priv->current_status & ~STATUS_RXOK); /* handle state changes */ if ((priv->current_status & STATUS_EWARN) && (!(priv->last_status & STATUS_EWARN))) { netdev_dbg(dev, "entered error warning state\n"); work_done += c_can_handle_state_change(dev, C_CAN_ERROR_WARNING); } if ((priv->current_status & STATUS_EPASS) && (!(priv->last_status & STATUS_EPASS))) { netdev_dbg(dev, "entered error passive state\n"); work_done += c_can_handle_state_change(dev, C_CAN_ERROR_PASSIVE); } if ((priv->current_status & STATUS_BOFF) && (!(priv->last_status & STATUS_BOFF))) { netdev_dbg(dev, "entered bus off state\n"); work_done += c_can_handle_state_change(dev, C_CAN_BUS_OFF); } /* handle bus recovery events */ if ((!(priv->current_status & STATUS_BOFF)) && (priv->last_status & STATUS_BOFF)) { netdev_dbg(dev, "left bus off state\n"); priv->can.state = CAN_STATE_ERROR_ACTIVE; } if ((!(priv->current_status & STATUS_EPASS)) && (priv->last_status & STATUS_EPASS)) { netdev_dbg(dev, "left error passive state\n"); priv->can.state = CAN_STATE_ERROR_ACTIVE; } priv->last_status = priv->current_status; /* handle lec errors on the bus */ lec_type = c_can_has_and_handle_berr(priv); if (lec_type) work_done += c_can_handle_bus_err(dev, lec_type); } else if ((irqstatus >= C_CAN_MSG_OBJ_RX_FIRST) && (irqstatus <= C_CAN_MSG_OBJ_RX_LAST)) { /* handle events corresponding to receive message objects */ work_done += c_can_do_rx_poll(dev, (quota - work_done)); } else if ((irqstatus >= C_CAN_MSG_OBJ_TX_FIRST) && (irqstatus <= C_CAN_MSG_OBJ_TX_LAST)) { /* handle events corresponding to transmit message objects */ c_can_do_tx(dev); } end: if (work_done < quota) { napi_complete(napi); /* enable all IRQs */ c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS); } return work_done; } static irqreturn_t c_can_isr(int irq, void *dev_id) { u16 irqstatus; struct net_device *dev = (struct net_device *)dev_id; struct c_can_priv *priv = netdev_priv(dev); irqstatus = priv->read_reg(priv, &priv->regs->interrupt); if (!irqstatus) return IRQ_NONE; /* disable all interrupts and schedule the NAPI */ c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); napi_schedule(&priv->napi); return IRQ_HANDLED; } static int c_can_open(struct net_device *dev) { int err; struct c_can_priv *priv = netdev_priv(dev); /* open the can device */ err = open_candev(dev); if (err) { netdev_err(dev, "failed to open can device\n"); return err; } /* register interrupt handler */ err = request_irq(dev->irq, &c_can_isr, IRQF_SHARED, dev->name, dev); if (err < 0) { netdev_err(dev, "failed to request interrupt\n"); goto exit_irq_fail; } /* start the c_can controller */ c_can_start(dev); napi_enable(&priv->napi); netif_start_queue(dev); return 0; exit_irq_fail: close_candev(dev); return err; } static int c_can_close(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); netif_stop_queue(dev); napi_disable(&priv->napi); c_can_stop(dev); free_irq(dev->irq, dev); close_candev(dev); return 0; } struct net_device *alloc_c_can_dev(void) { struct net_device *dev; struct c_can_priv *priv; dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM); if (!dev) return NULL; priv = netdev_priv(dev); netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT); priv->dev = dev; priv->can.bittiming_const = &c_can_bittiming_const; priv->can.do_set_mode = c_can_set_mode; priv->can.do_get_berr_counter = c_can_get_berr_counter; priv->can.ctrlmode_supported = CAN_CTRLMODE_ONE_SHOT | CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_BERR_REPORTING; return dev; } EXPORT_SYMBOL_GPL(alloc_c_can_dev); void free_c_can_dev(struct net_device *dev) { free_candev(dev); } EXPORT_SYMBOL_GPL(free_c_can_dev); static const struct net_device_ops c_can_netdev_ops = { .ndo_open = c_can_open, .ndo_stop = c_can_close, .ndo_start_xmit = c_can_start_xmit, }; int register_c_can_dev(struct net_device *dev) { dev->flags |= IFF_ECHO; /* we support local echo */ dev->netdev_ops = &c_can_netdev_ops; return register_candev(dev); } EXPORT_SYMBOL_GPL(register_c_can_dev); void unregister_c_can_dev(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); /* disable all interrupts */ c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS); unregister_candev(dev); } EXPORT_SYMBOL_GPL(unregister_c_can_dev); MODULE_AUTHOR("Bhupesh Sharma "); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller");