--- /dev/null
+/*
+ * 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");
projects / linux-beck.git / commitdiff