diff options
Diffstat (limited to 'drivers/net/can/c_can/c_can.c')
| -rw-r--r-- | drivers/net/can/c_can/c_can.c | 1158 |
1 files changed, 1158 insertions, 0 deletions
diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c new file mode 100644 index 0000000..1405078 --- /dev/null +++ b/drivers/net/can/c_can/c_can.c @@ -0,0 +1,1158 @@ +/* + * CAN bus driver for Bosch C_CAN controller + * + * Copyright (C) 2010 ST Microelectronics + * Bhupesh Sharma <bhupesh.sharma@st.com> + * + * Borrowed heavily from the C_CAN driver originally written by: + * Copyright (C) 2007 + * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de> + * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch> + * + * TX and RX NAPI implementation has been borrowed from at91 CAN driver + * written by: + * Copyright + * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de> + * (C) 2008, 2009 by Marc Kleine-Budde <kernel@pengutronix.de> + * + * 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 <linux/kernel.h> +#include <linux/version.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/netdevice.h> +#include <linux/if_arp.h> +#include <linux/if_ether.h> +#include <linux/list.h> +#include <linux/delay.h> +#include <linux/io.h> + +#include <linux/can.h> +#include <linux/can/dev.h> +#include <linux/can/error.h> + +#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); + + /* enable status change, error and module interrupts */ + c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS); + + /* 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; +} + +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 <bhupesh.sharma@st.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller"); |