text: /*
   * Core driver for the CC770 and AN82527 CAN controllers
   *
   * Copyright (C) 2009, 2011 Wolfgang Grandegger <wg@grandegger.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the version 2 of the GNU General Public License
   * as published by the Free Software Foundation
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU General Public License for more details.
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/types.h>
  #include <linux/fcntl.h>
  #include <linux/interrupt.h>
  #include <linux/ptrace.h>
  #include <linux/string.h>
  #include <linux/errno.h>
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <linux/if_ether.h>
  #include <linux/skbuff.h>
  #include <linux/delay.h>
  
  #include <linux/can.h>
  #include <linux/can/dev.h>
  #include <linux/can/error.h>
  #include <linux/can/platform/cc770.h>
  
  #include "cc770.h"
  
  MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
  MODULE_LICENSE("GPL v2");
  MODULE_DESCRIPTION(KBUILD_MODNAME "CAN netdevice driver");
  
  /*
   * The CC770 is a CAN controller from Bosch, which is 100% compatible
   * with the AN82527 from Intel, but with "bugs" being fixed and some
   * additional functionality, mainly:
   *
   * 1. RX and TX error counters are readable.
   * 2. Support of silent (listen-only) mode.
   * 3. Message object 15 can receive all types of frames, also RTR and EFF.
   *
   * Details are available from Bosch's "CC770_Product_Info_2007-01.pdf",
   * which explains in detail the compatibility between the CC770 and the
   * 82527. This driver use the additional functionality 3. on real CC770
   * devices. Unfortunately, the CC770 does still not store the message
   * identifier of received remote transmission request frames and
   * therefore it's set to 0.
   *
   * The message objects 1..14 can be used for TX and RX while the message
   * objects 15 is optimized for RX. It has a shadow register for reliable
   * data receiption under heavy bus load. Therefore it makes sense to use
   * this message object for the needed use case. The frame type (EFF/SFF)
   * for the message object 15 can be defined via kernel module parameter
   * "msgobj15_eff". If not equal 0, it will receive 29-bit EFF frames,
   * otherwise 11 bit SFF messages.
   */
  static int msgobj15_eff;
  module_param(msgobj15_eff, int, S_IRUGO);
  MODULE_PARM_DESC(msgobj15_eff, "Extended 29-bit frames for message object 15 "
  		 "(default: 11-bit standard frames)");
  
  static int i82527_compat;
  module_param(i82527_compat, int, S_IRUGO);
  MODULE_PARM_DESC(i82527_compat, "Strict Intel 82527 comptibility mode "
  		 "without using additional functions");
  
  /*
   * This driver uses the last 5 message objects 11..15. The definitions
   * and structure below allows to configure and assign them to the real
   * message object.
   */
  static unsigned char cc770_obj_flags[CC770_OBJ_MAX] = {
  	[CC770_OBJ_RX0] = CC770_OBJ_FLAG_RX,
  	[CC770_OBJ_RX1] = CC770_OBJ_FLAG_RX | CC770_OBJ_FLAG_EFF,
  	[CC770_OBJ_RX_RTR0] = CC770_OBJ_FLAG_RX | CC770_OBJ_FLAG_RTR,
  	[CC770_OBJ_RX_RTR1] = CC770_OBJ_FLAG_RX | CC770_OBJ_FLAG_RTR |
  			      CC770_OBJ_FLAG_EFF,
  	[CC770_OBJ_TX] = 0,
  };
  
  static const struct can_bittiming_const cc770_bittiming_const = {
  	.name = KBUILD_MODNAME,
  	.tseg1_min = 1,
  	.tseg1_max = 16,
  	.tseg2_min = 1,
  	.tseg2_max = 8,
  	.sjw_max = 4,
  	.brp_min = 1,
  	.brp_max = 64,
  	.brp_inc = 1,
  };
  
  static inline int intid2obj(unsigned int intid)
  {
  	if (intid == 2)
  		return 0;
  	else
  		return MSGOBJ_LAST + 2 - intid;
  }
  
  static void enable_all_objs(const struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	u8 msgcfg;
  	unsigned char obj_flags;
  	unsigned int o, mo;
  
  	for (o = 0; o < ARRAY_SIZE(priv->obj_flags); o++) {
  		obj_flags = priv->obj_flags[o];
  		mo = obj2msgobj(o);
  
  		if (obj_flags & CC770_OBJ_FLAG_RX) {
  			/*
  			 * We don't need extra objects for RTR and EFF if
  			 * the additional CC770 functions are enabled.
  			 */
  			if (priv->control_normal_mode & CTRL_EAF) {
  				if (o > 0)
  					continue;
  				netdev_dbg(dev, "Message object %d for "
  					   "RX data, RTR, SFF and EFF\n", mo);
  			} else {
  				netdev_dbg(dev,
  					   "Message object %d for RX %s %s\n",
  					   mo, obj_flags & CC770_OBJ_FLAG_RTR ?
  					   "RTR" : "data",
  					   obj_flags & CC770_OBJ_FLAG_EFF ?
  					   "EFF" : "SFF");
  			}
  
  			if (obj_flags & CC770_OBJ_FLAG_EFF)
  				msgcfg = MSGCFG_XTD;
  			else
  				msgcfg = 0;
  			if (obj_flags & CC770_OBJ_FLAG_RTR)
  				msgcfg |= MSGCFG_DIR;
  
  			cc770_write_reg(priv, msgobj[mo].config, msgcfg);
  			cc770_write_reg(priv, msgobj[mo].ctrl0,
  					MSGVAL_SET | TXIE_RES |
  					RXIE_SET | INTPND_RES);
  
  			if (obj_flags & CC770_OBJ_FLAG_RTR)
  				cc770_write_reg(priv, msgobj[mo].ctrl1,
  						NEWDAT_RES | CPUUPD_SET |
  						TXRQST_RES | RMTPND_RES);
  			else
  				cc770_write_reg(priv, msgobj[mo].ctrl1,
  						NEWDAT_RES | MSGLST_RES |
  						TXRQST_RES | RMTPND_RES);
  		} else {
  			netdev_dbg(dev, "Message object %d for "
  				   "TX data, RTR, SFF and EFF\n", mo);
  
  			cc770_write_reg(priv, msgobj[mo].ctrl1,
  					RMTPND_RES | TXRQST_RES |
  					CPUUPD_RES | NEWDAT_RES);
  			cc770_write_reg(priv, msgobj[mo].ctrl0,
  					MSGVAL_RES | TXIE_RES |
  					RXIE_RES | INTPND_RES);
  		}
  	}
  }
  
  static void disable_all_objs(const struct cc770_priv *priv)
  {
  	int o, mo;
  
  	for (o = 0; o <  ARRAY_SIZE(priv->obj_flags); o++) {
  		mo = obj2msgobj(o);
  
  		if (priv->obj_flags[o] & CC770_OBJ_FLAG_RX) {
  			if (o > 0 && priv->control_normal_mode & CTRL_EAF)
  				continue;
  
  			cc770_write_reg(priv, msgobj[mo].ctrl1,
  					NEWDAT_RES | MSGLST_RES |
  					TXRQST_RES | RMTPND_RES);
  			cc770_write_reg(priv, msgobj[mo].ctrl0,
  					MSGVAL_RES | TXIE_RES |
  					RXIE_RES | INTPND_RES);
  		} else {
  			/* Clear message object for send */
  			cc770_write_reg(priv, msgobj[mo].ctrl1,
  					RMTPND_RES | TXRQST_RES |
  					CPUUPD_RES | NEWDAT_RES);
  			cc770_write_reg(priv, msgobj[mo].ctrl0,
  					MSGVAL_RES | TXIE_RES |
  					RXIE_RES | INTPND_RES);
  		}
  	}
  }
  
  static void set_reset_mode(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  
  	/* Enable configuration and puts chip in bus-off, disable interrupts */
  	cc770_write_reg(priv, control, CTRL_CCE | CTRL_INI);
  
  	priv->can.state = CAN_STATE_STOPPED;
  
  	/* Clear interrupts */
  	cc770_read_reg(priv, interrupt);
  
  	/* Clear status register */
  	cc770_write_reg(priv, status, 0);
  
  	/* Disable all used message objects */
  	disable_all_objs(priv);
  }
  
  static void set_normal_mode(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  
  	/* Clear interrupts */
  	cc770_read_reg(priv, interrupt);
  
  	/* Clear status register and pre-set last error code */
  	cc770_write_reg(priv, status, STAT_LEC_MASK);
  
  	/* Enable all used message objects*/
  	enable_all_objs(dev);
  
  	/*
  	 * Clear bus-off, interrupts only for errors,
  	 * not for status change
  	 */
  	cc770_write_reg(priv, control, priv->control_normal_mode);
  
  	priv->can.state = CAN_STATE_ERROR_ACTIVE;
  }
  
  static void chipset_init(struct cc770_priv *priv)
  {
  	int mo, id, data;
  
  	/* Enable configuration and put chip in bus-off, disable interrupts */
  	cc770_write_reg(priv, control, (CTRL_CCE | CTRL_INI));
  
  	/* Set CLKOUT divider and slew rates */
  	cc770_write_reg(priv, clkout, priv->clkout);
  
  	/* Configure CPU interface / CLKOUT enable */
  	cc770_write_reg(priv, cpu_interface, priv->cpu_interface);
  
  	/* Set bus configuration  */
  	cc770_write_reg(priv, bus_config, priv->bus_config);
  
  	/* Clear interrupts */
  	cc770_read_reg(priv, interrupt);
  
  	/* Clear status register */
  	cc770_write_reg(priv, status, 0);
  
  	/* Clear and invalidate message objects */
  	for (mo = MSGOBJ_FIRST; mo <= MSGOBJ_LAST; mo++) {
  		cc770_write_reg(priv, msgobj[mo].ctrl0,
  				INTPND_UNC | RXIE_RES |
  				TXIE_RES | MSGVAL_RES);
  		cc770_write_reg(priv, msgobj[mo].ctrl0,
  				INTPND_RES | RXIE_RES |
  				TXIE_RES | MSGVAL_RES);
  		cc770_write_reg(priv, msgobj[mo].ctrl1,
  				NEWDAT_RES | MSGLST_RES |
  				TXRQST_RES | RMTPND_RES);
  		for (data = 0; data < 8; data++)
  			cc770_write_reg(priv, msgobj[mo].data[data], 0);
  		for (id = 0; id < 4; id++)
  			cc770_write_reg(priv, msgobj[mo].id[id], 0);
  		cc770_write_reg(priv, msgobj[mo].config, 0);
  	}
  
  	/* Set all global ID masks to "don't care" */
  	cc770_write_reg(priv, global_mask_std[0], 0);
  	cc770_write_reg(priv, global_mask_std[1], 0);
  	cc770_write_reg(priv, global_mask_ext[0], 0);
  	cc770_write_reg(priv, global_mask_ext[1], 0);
  	cc770_write_reg(priv, global_mask_ext[2], 0);
  	cc770_write_reg(priv, global_mask_ext[3], 0);
  
  }
  
  static int cc770_probe_chip(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  
  	/* Enable configuration, put chip in bus-off, disable ints */
  	cc770_write_reg(priv, control, CTRL_CCE | CTRL_EAF | CTRL_INI);
  	/* Configure cpu interface / CLKOUT disable */
  	cc770_write_reg(priv, cpu_interface, priv->cpu_interface);
  
  	/*
  	 * Check if hardware reset is still inactive or maybe there
  	 * is no chip in this address space
  	 */
  	if (cc770_read_reg(priv, cpu_interface) & CPUIF_RST) {
  		netdev_info(dev, "probing @0x%p failed (reset)\n",
  			    priv->reg_base);
  		return -ENODEV;
  	}
  
  	/* Write and read back test pattern (some arbitrary values) */
  	cc770_write_reg(priv, msgobj[1].data[1], 0x25);
  	cc770_write_reg(priv, msgobj[2].data[3], 0x52);
  	cc770_write_reg(priv, msgobj[10].data[6], 0xc3);
  	if ((cc770_read_reg(priv, msgobj[1].data[1]) != 0x25) ||
  	    (cc770_read_reg(priv, msgobj[2].data[3]) != 0x52) ||
  	    (cc770_read_reg(priv, msgobj[10].data[6]) != 0xc3)) {
  		netdev_info(dev, "probing @0x%p failed (pattern)\n",
  			    priv->reg_base);
  		return -ENODEV;
  	}
  
  	/* Check if this chip is a CC770 supporting additional functions */
  	if (cc770_read_reg(priv, control) & CTRL_EAF)
  		priv->control_normal_mode |= CTRL_EAF;
  
  	return 0;
  }
  
  static void cc770_start(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  
  	/* leave reset mode */
  	if (priv->can.state != CAN_STATE_STOPPED)
  		set_reset_mode(dev);
  
  	/* leave reset mode */
  	set_normal_mode(dev);
  }
  
  static int cc770_set_mode(struct net_device *dev, enum can_mode mode)
  {
  	switch (mode) {
  	case CAN_MODE_START:
  		cc770_start(dev);
  		netif_wake_queue(dev);
  		break;
  
  	default:
  		return -EOPNOTSUPP;
  	}
  
  	return 0;
  }
  
  static int cc770_set_bittiming(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	struct can_bittiming *bt = &priv->can.bittiming;
  	u8 btr0, btr1;
  
  	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
  	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
  		(((bt->phase_seg2 - 1) & 0x7) << 4);
  	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
  		btr1 |= 0x80;
  
  	netdev_info(dev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
  
  	cc770_write_reg(priv, bit_timing_0, btr0);
  	cc770_write_reg(priv, bit_timing_1, btr1);
  
  	return 0;
  }
  
  static int cc770_get_berr_counter(const struct net_device *dev,
  				  struct can_berr_counter *bec)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  
  	bec->txerr = cc770_read_reg(priv, tx_error_counter);
  	bec->rxerr = cc770_read_reg(priv, rx_error_counter);
  
  	return 0;
  }
  
  static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	struct net_device_stats *stats = &dev->stats;
  	struct can_frame *cf = (struct can_frame *)skb->data;
  	unsigned int mo = obj2msgobj(CC770_OBJ_TX);
  	u8 dlc, rtr;
  	u32 id;
  	int i;
  
  	if (can_dropped_invalid_skb(dev, skb))
  		return NETDEV_TX_OK;
  
  	if ((cc770_read_reg(priv,
  			    msgobj[mo].ctrl1) & TXRQST_UNC) == TXRQST_SET) {
  		netdev_err(dev, "TX register is still occupied!\n");
  		return NETDEV_TX_BUSY;
  	}
  
  	netif_stop_queue(dev);
  
  	dlc = cf->can_dlc;
  	id = cf->can_id;
  	if (cf->can_id & CAN_RTR_FLAG)
  		rtr = 0;
  	else
  		rtr = MSGCFG_DIR;
  	cc770_write_reg(priv, msgobj[mo].ctrl1,
  			RMTPND_RES | TXRQST_RES | CPUUPD_SET | NEWDAT_RES);
  	cc770_write_reg(priv, msgobj[mo].ctrl0,
  			MSGVAL_SET | TXIE_SET | RXIE_RES | INTPND_RES);
  	if (id & CAN_EFF_FLAG) {
  		id &= CAN_EFF_MASK;
  		cc770_write_reg(priv, msgobj[mo].config,
  				(dlc << 4) | rtr | MSGCFG_XTD);
  		cc770_write_reg(priv, msgobj[mo].id[3], id << 3);
  		cc770_write_reg(priv, msgobj[mo].id[2], id >> 5);
  		cc770_write_reg(priv, msgobj[mo].id[1], id >> 13);
  		cc770_write_reg(priv, msgobj[mo].id[0], id >> 21);
  	} else {
  		id &= CAN_SFF_MASK;
  		cc770_write_reg(priv, msgobj[mo].config, (dlc << 4) | rtr);
  		cc770_write_reg(priv, msgobj[mo].id[0], id >> 3);
  		cc770_write_reg(priv, msgobj[mo].id[1], id << 5);
  	}
  
  	for (i = 0; i < dlc; i++)
  		cc770_write_reg(priv, msgobj[mo].data[i], cf->data[i]);
  
  	/* Store echo skb before starting the transfer */
  	can_put_echo_skb(skb, dev, 0);
  
  	cc770_write_reg(priv, msgobj[mo].ctrl1,
  			RMTPND_RES | TXRQST_SET | CPUUPD_RES | NEWDAT_UNC);
  
  	stats->tx_bytes += dlc;
  
  
  	/*
  	 * HM: We had some cases of repeated IRQs so make sure the
  	 * INT is acknowledged I know it's already further up, but
  	 * doing again fixed the issue
  	 */
  	cc770_write_reg(priv, msgobj[mo].ctrl0,
  			MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES);
  
  	return NETDEV_TX_OK;
  }
  
  static void cc770_rx(struct net_device *dev, unsigned int mo, u8 ctrl1)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	struct net_device_stats *stats = &dev->stats;
  	struct can_frame *cf;
  	struct sk_buff *skb;
  	u8 config;
  	u32 id;
  	int i;
  
  	skb = alloc_can_skb(dev, &cf);
  	if (!skb)
  		return;
  
  	config = cc770_read_reg(priv, msgobj[mo].config);
  
  	if (ctrl1 & RMTPND_SET) {
  		/*
  		 * Unfortunately, the chip does not store the real message
  		 * identifier of the received remote transmission request
  		 * frame. Therefore we set it to 0.
  		 */
  		cf->can_id = CAN_RTR_FLAG;
  		if (config & MSGCFG_XTD)
  			cf->can_id |= CAN_EFF_FLAG;
  		cf->can_dlc = 0;
  	} else {
  		if (config & MSGCFG_XTD) {
  			id = cc770_read_reg(priv, msgobj[mo].id[3]);
  			id |= cc770_read_reg(priv, msgobj[mo].id[2]) << 8;
  			id |= cc770_read_reg(priv, msgobj[mo].id[1]) << 16;
  			id |= cc770_read_reg(priv, msgobj[mo].id[0]) << 24;
  			id >>= 3;
  			id |= CAN_EFF_FLAG;
  		} else {
  			id = cc770_read_reg(priv, msgobj[mo].id[1]);
  			id |= cc770_read_reg(priv, msgobj[mo].id[0]) << 8;
  			id >>= 5;
  		}
  
  		cf->can_id = id;
  		cf->can_dlc = get_can_dlc((config & 0xf0) >> 4);
  		for (i = 0; i < cf->can_dlc; i++)
  			cf->data[i] = cc770_read_reg(priv, msgobj[mo].data[i]);
  	}
  	netif_rx(skb);
  
  	stats->rx_packets++;
  	stats->rx_bytes += cf->can_dlc;
  }
  
  static int cc770_err(struct net_device *dev, u8 status)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	struct net_device_stats *stats = &dev->stats;
  	struct can_frame *cf;
  	struct sk_buff *skb;
  	u8 lec;
  
  	netdev_dbg(dev, "status interrupt (%#x)\n", status);
  
  	skb = alloc_can_err_skb(dev, &cf);
  	if (!skb)
  		return -ENOMEM;
  
  	/* Use extended functions of the CC770 */
  	if (priv->control_normal_mode & CTRL_EAF) {
  		cf->data[6] = cc770_read_reg(priv, tx_error_counter);
  		cf->data[7] = cc770_read_reg(priv, rx_error_counter);
  	}
  
  	if (status & STAT_BOFF) {
  		/* Disable interrupts */
  		cc770_write_reg(priv, control, CTRL_INI);
  		cf->can_id |= CAN_ERR_BUSOFF;
  		priv->can.state = CAN_STATE_BUS_OFF;
  		can_bus_off(dev);
  	} else if (status & STAT_WARN) {
  		cf->can_id |= CAN_ERR_CRTL;
  		/* Only the CC770 does show error passive */
  		if (cf->data[7] > 127) {
  			cf->data[1] = CAN_ERR_CRTL_RX_PASSIVE |
  				CAN_ERR_CRTL_TX_PASSIVE;
  			priv->can.state = CAN_STATE_ERROR_PASSIVE;
  			priv->can.can_stats.error_passive++;
  		} else {
  			cf->data[1] = CAN_ERR_CRTL_RX_WARNING |
  				CAN_ERR_CRTL_TX_WARNING;
  			priv->can.state = CAN_STATE_ERROR_WARNING;
  			priv->can.can_stats.error_warning++;
  		}
  	} else {
  		/* Back to error avtive */
  		cf->can_id |= CAN_ERR_PROT;
  		cf->data[2] = CAN_ERR_PROT_ACTIVE;
  		priv->can.state = CAN_STATE_ERROR_ACTIVE;
  	}
  
  	lec = status & STAT_LEC_MASK;
  	if (lec < 7 && lec > 0) {
  		if (lec == STAT_LEC_ACK) {
  			cf->can_id |= CAN_ERR_ACK;
  		} else {
  			cf->can_id |= CAN_ERR_PROT;
  			switch (lec) {
  			case STAT_LEC_STUFF:
  				cf->data[2] |= CAN_ERR_PROT_STUFF;
  				break;
  			case STAT_LEC_FORM:
  				cf->data[2] |= CAN_ERR_PROT_FORM;
  				break;
  			case STAT_LEC_BIT1:
  				cf->data[2] |= CAN_ERR_PROT_BIT1;
  				break;
  			case STAT_LEC_BIT0:
  				cf->data[2] |= CAN_ERR_PROT_BIT0;
  				break;
  			case STAT_LEC_CRC:
  				cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
  				break;
  			}
  		}
  	}
  
  	netif_rx(skb);
  
  	stats->rx_packets++;
  	stats->rx_bytes += cf->can_dlc;
  
  	return 0;
  }
  
  static int cc770_status_interrupt(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	u8 status;
  
  	status = cc770_read_reg(priv, status);
  	/* Reset the status register including RXOK and TXOK */
  	cc770_write_reg(priv, status, STAT_LEC_MASK);
  
  	if (status & (STAT_WARN | STAT_BOFF) ||
  	    (status & STAT_LEC_MASK) != STAT_LEC_MASK) {
  		cc770_err(dev, status);
  		return status & STAT_BOFF;
  	}
  
  	return 0;
  }
  
  static void cc770_rx_interrupt(struct net_device *dev, unsigned int o)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	struct net_device_stats *stats = &dev->stats;
  	unsigned int mo = obj2msgobj(o);
  	u8 ctrl1;
  	int n = CC770_MAX_MSG;
  
  	while (n--) {
  		ctrl1 = cc770_read_reg(priv, msgobj[mo].ctrl1);
  
  		if (!(ctrl1 & NEWDAT_SET))  {
  			/* Check for RTR if additional functions are enabled */
  			if (priv->control_normal_mode & CTRL_EAF) {
  				if (!(cc770_read_reg(priv, msgobj[mo].ctrl0) &
  				      INTPND_SET))
  					break;
  			} else {
  				break;
  			}
  		}
  
  		if (ctrl1 & MSGLST_SET) {
  			stats->rx_over_errors++;
  			stats->rx_errors++;
  		}
  		if (mo < MSGOBJ_LAST)
  			cc770_write_reg(priv, msgobj[mo].ctrl1,
  					NEWDAT_RES | MSGLST_RES |
  					TXRQST_UNC | RMTPND_UNC);
  		cc770_rx(dev, mo, ctrl1);
  
  		cc770_write_reg(priv, msgobj[mo].ctrl0,
  				MSGVAL_SET | TXIE_RES |
  				RXIE_SET | INTPND_RES);
  		cc770_write_reg(priv, msgobj[mo].ctrl1,
  				NEWDAT_RES | MSGLST_RES |
  				TXRQST_RES | RMTPND_RES);
  	}
  }
  
  static void cc770_rtr_interrupt(struct net_device *dev, unsigned int o)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	unsigned int mo = obj2msgobj(o);
  	u8 ctrl0, ctrl1;
  	int n = CC770_MAX_MSG;
  
  	while (n--) {
  		ctrl0 = cc770_read_reg(priv, msgobj[mo].ctrl0);
  		if (!(ctrl0 & INTPND_SET))
  			break;
  
  		ctrl1 = cc770_read_reg(priv, msgobj[mo].ctrl1);
  		cc770_rx(dev, mo, ctrl1);
  
  		cc770_write_reg(priv, msgobj[mo].ctrl0,
  				MSGVAL_SET | TXIE_RES |
  				RXIE_SET | INTPND_RES);
  		cc770_write_reg(priv, msgobj[mo].ctrl1,
  				NEWDAT_RES | CPUUPD_SET |
  				TXRQST_RES | RMTPND_RES);
  	}
  }
  
  static void cc770_tx_interrupt(struct net_device *dev, unsigned int o)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	struct net_device_stats *stats = &dev->stats;
  	unsigned int mo = obj2msgobj(o);
  
  	/* Nothing more to send, switch off interrupts */
  	cc770_write_reg(priv, msgobj[mo].ctrl0,
  			MSGVAL_RES | TXIE_RES | RXIE_RES | INTPND_RES);
  	/*
  	 * We had some cases of repeated IRQ so make sure the
  	 * INT is acknowledged
  	 */
  	cc770_write_reg(priv, msgobj[mo].ctrl0,
  			MSGVAL_UNC | TXIE_UNC | RXIE_UNC | INTPND_RES);
  
  	stats->tx_packets++;
  	can_get_echo_skb(dev, 0);
  	netif_wake_queue(dev);
  }
  
  static irqreturn_t cc770_interrupt(int irq, void *dev_id)
  {
  	struct net_device *dev = (struct net_device *)dev_id;
  	struct cc770_priv *priv = netdev_priv(dev);
  	u8 intid;
  	int o, n = 0;
  
  	/* Shared interrupts and IRQ off? */
  	if (priv->can.state == CAN_STATE_STOPPED)
  		return IRQ_NONE;
  
  	if (priv->pre_irq)
  		priv->pre_irq(priv);
  
  	while (n < CC770_MAX_IRQ) {
  		/* Read the highest pending interrupt request */
  		intid = cc770_read_reg(priv, interrupt);
  		if (!intid)
  			break;
  		n++;
  
  		if (intid == 1) {
  			/* Exit in case of bus-off */
  			if (cc770_status_interrupt(dev))
  				break;
  		} else {
  			o = intid2obj(intid);
  
  			if (o >= CC770_OBJ_MAX) {
  				netdev_err(dev, "Unexpected interrupt id %d\n",
  					   intid);
  				continue;
  			}
  
  			if (priv->obj_flags[o] & CC770_OBJ_FLAG_RTR)
  				cc770_rtr_interrupt(dev, o);
  			else if (priv->obj_flags[o] & CC770_OBJ_FLAG_RX)
  				cc770_rx_interrupt(dev, o);
  			else
  				cc770_tx_interrupt(dev, o);
  		}
  	}
  
  	if (priv->post_irq)
  		priv->post_irq(priv);
  
  	if (n >= CC770_MAX_IRQ)
  		netdev_dbg(dev, "%d messages handled in ISR", n);
  
  	return (n) ? IRQ_HANDLED : IRQ_NONE;
  }
  
  static int cc770_open(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	int err;
  
  	/* set chip into reset mode */
  	set_reset_mode(dev);
  
  	/* common open */
  	err = open_candev(dev);
  	if (err)
  		return err;
  
  	err = request_irq(dev->irq, &cc770_interrupt, priv->irq_flags,
  			  dev->name, dev);
  	if (err) {
  		close_candev(dev);
  		return -EAGAIN;
  	}
  
  	/* init and start chip */
  	cc770_start(dev);
  
  	netif_start_queue(dev);
  
  	return 0;
  }
  
  static int cc770_close(struct net_device *dev)
  {
  	netif_stop_queue(dev);
  	set_reset_mode(dev);
  
  	free_irq(dev->irq, dev);
  	close_candev(dev);
  
  	return 0;
  }
  
  struct net_device *alloc_cc770dev(int sizeof_priv)
  {
  	struct net_device *dev;
  	struct cc770_priv *priv;
  
  	dev = alloc_candev(sizeof(struct cc770_priv) + sizeof_priv,
  			   CC770_ECHO_SKB_MAX);
  	if (!dev)
  		return NULL;
  
  	priv = netdev_priv(dev);
  
  	priv->dev = dev;
  	priv->can.bittiming_const = &cc770_bittiming_const;
  	priv->can.do_set_bittiming = cc770_set_bittiming;
  	priv->can.do_set_mode = cc770_set_mode;
  	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
  
  	memcpy(priv->obj_flags, cc770_obj_flags, sizeof(cc770_obj_flags));
  
  	if (sizeof_priv)
  		priv->priv = (void *)priv + sizeof(struct cc770_priv);
  
  	return dev;
  }
  EXPORT_SYMBOL_GPL(alloc_cc770dev);
  
  void free_cc770dev(struct net_device *dev)
  {
  	free_candev(dev);
  }
  EXPORT_SYMBOL_GPL(free_cc770dev);
  
  static const struct net_device_ops cc770_netdev_ops = {
  	.ndo_open = cc770_open,
  	.ndo_stop = cc770_close,
  	.ndo_start_xmit = cc770_start_xmit,
  };
  
  int register_cc770dev(struct net_device *dev)
  {
  	struct cc770_priv *priv = netdev_priv(dev);
  	int err;
  
  	err = cc770_probe_chip(dev);
  	if (err)
  		return err;
  
  	dev->netdev_ops = &cc770_netdev_ops;
  
  	dev->flags |= IFF_ECHO;	/* we support local echo */
  
  	/* Should we use additional functions? */
  	if (!i82527_compat && priv->control_normal_mode & CTRL_EAF) {
  		priv->can.do_get_berr_counter = cc770_get_berr_counter;
  		priv->control_normal_mode = CTRL_IE | CTRL_EAF | CTRL_EIE;
  		netdev_dbg(dev, "i82527 mode with additional functions\n");
  	} else {
  		priv->control_normal_mode = CTRL_IE | CTRL_EIE;
  		netdev_dbg(dev, "strict i82527 compatibility mode\n");
  	}
  
  	chipset_init(priv);
  	set_reset_mode(dev);
  
  	return register_candev(dev);
  }
  EXPORT_SYMBOL_GPL(register_cc770dev);
  
  void unregister_cc770dev(struct net_device *dev)
  {
  	set_reset_mode(dev);
  	unregister_candev(dev);
  }
  EXPORT_SYMBOL_GPL(unregister_cc770dev);
  
  static __init int cc770_init(void)
  {
  	if (msgobj15_eff) {
  		cc770_obj_flags[CC770_OBJ_RX0] |= CC770_OBJ_FLAG_EFF;
  		cc770_obj_flags[CC770_OBJ_RX1] &= ~CC770_OBJ_FLAG_EFF;
  	}
  
  	pr_info("CAN netdevice driver\n");
  
  	return 0;
  }
  module_init(cc770_init);
  
  static __exit void cc770_exit(void)
  {
  	pr_info("driver removed\n");
  }
  module_exit(cc770_exit);
  