drivers/net/can/bfin_can.c - kernel/msm-4.9 - Gitiles

 /*
  * Blackfin On-Chip CAN Driver
  *
  * Copyright 2004-2009 Analog Devices Inc.
  *
  * Enter bugs at http://blackfin.uclinux.org/
  *
  * Licensed under the GPL-2 or later.
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/bitops.h>
 #include <linux/interrupt.h>
 #include <linux/errno.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
 #include <linux/platform_device.h>

 #include <linux/can/dev.h>
 #include <linux/can/error.h>

 #include <asm/bfin_can.h>
 #include <asm/portmux.h>

 #define DRV_NAME "bfin_can"
 #define BFIN_CAN_TIMEOUT 100
 #define TX_ECHO_SKB_MAX  1

 /*
  * bfin can private data
  */
 struct bfin_can_priv {
 	struct can_priv can;	/* must be the first member */
 	struct net_device *dev;
 	void __iomem *membase;
 	int rx_irq;
 	int tx_irq;
 	int err_irq;
 	unsigned short *pin_list;
 };

 /*
  * bfin can timing parameters
  */
 static struct can_bittiming_const bfin_can_bittiming_const = {
 	.name = DRV_NAME,
 	.tseg1_min = 1,
 	.tseg1_max = 16,
 	.tseg2_min = 1,
 	.tseg2_max = 8,
 	.sjw_max = 4,
 	/*
 	 * Although the BRP field can be set to any value, it is recommended
 	 * that the value be greater than or equal to 4, as restrictions
 	 * apply to the bit timing configuration when BRP is less than 4.
 	 */
 	.brp_min = 4,
 	.brp_max = 1024,
 	.brp_inc = 1,
 };

 static int bfin_can_set_bittiming(struct net_device *dev)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	struct can_bittiming *bt = &priv->can.bittiming;
 	u16 clk, timing;

 	clk = bt->brp - 1;
 	timing = ((bt->sjw - 1) << 8) | (bt->prop_seg + bt->phase_seg1 - 1) |
 		((bt->phase_seg2 - 1) << 4);

 	/*
 	 * If the SAM bit is set, the input signal is oversampled three times
 	 * at the SCLK rate.
 	 */
 	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 		timing |= SAM;

 	bfin_write16(&reg->clock, clk);
 	bfin_write16(&reg->timing, timing);

 	dev_info(dev->dev.parent, "setting CLOCK=0x%04x TIMING=0x%04x\n",
 			clk, timing);

 	return 0;
 }

 static void bfin_can_set_reset_mode(struct net_device *dev)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	int timeout = BFIN_CAN_TIMEOUT;
 	int i;

 	/* disable interrupts */
 	bfin_write16(&reg->mbim1, 0);
 	bfin_write16(&reg->mbim2, 0);
 	bfin_write16(&reg->gim, 0);

 	/* reset can and enter configuration mode */
 	bfin_write16(&reg->control, SRS | CCR);
 	SSYNC();
 	bfin_write16(&reg->control, CCR);
 	SSYNC();
 	while (!(bfin_read16(&reg->control) & CCA)) {
 		udelay(10);
 		if (--timeout == 0) {
 			dev_err(dev->dev.parent,
 					"fail to enter configuration mode\n");
 			BUG();
 		}
 	}

 	/*
 	 * All mailbox configurations are marked as inactive
 	 * by writing to CAN Mailbox Configuration Registers 1 and 2
 	 * For all bits: 0 - Mailbox disabled, 1 - Mailbox enabled
 	 */
 	bfin_write16(&reg->mc1, 0);
 	bfin_write16(&reg->mc2, 0);

 	/* Set Mailbox Direction */
 	bfin_write16(&reg->md1, 0xFFFF);   /* mailbox 1-16 are RX */
 	bfin_write16(&reg->md2, 0);   /* mailbox 17-32 are TX */

 	/* RECEIVE_STD_CHL */
 	for (i = 0; i < 2; i++) {
 		bfin_write16(&reg->chl[RECEIVE_STD_CHL + i].id0, 0);
 		bfin_write16(&reg->chl[RECEIVE_STD_CHL + i].id1, AME);
 		bfin_write16(&reg->chl[RECEIVE_STD_CHL + i].dlc, 0);
 		bfin_write16(&reg->msk[RECEIVE_STD_CHL + i].amh, 0x1FFF);
 		bfin_write16(&reg->msk[RECEIVE_STD_CHL + i].aml, 0xFFFF);
 	}

 	/* RECEIVE_EXT_CHL */
 	for (i = 0; i < 2; i++) {
 		bfin_write16(&reg->chl[RECEIVE_EXT_CHL + i].id0, 0);
 		bfin_write16(&reg->chl[RECEIVE_EXT_CHL + i].id1, AME | IDE);
 		bfin_write16(&reg->chl[RECEIVE_EXT_CHL + i].dlc, 0);
 		bfin_write16(&reg->msk[RECEIVE_EXT_CHL + i].amh, 0x1FFF);
 		bfin_write16(&reg->msk[RECEIVE_EXT_CHL + i].aml, 0xFFFF);
 	}

 	bfin_write16(&reg->mc2, BIT(TRANSMIT_CHL - 16));
 	bfin_write16(&reg->mc1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
 	SSYNC();

 	priv->can.state = CAN_STATE_STOPPED;
 }

 static void bfin_can_set_normal_mode(struct net_device *dev)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	int timeout = BFIN_CAN_TIMEOUT;

 	/*
 	 * leave configuration mode
 	 */
 	bfin_write16(&reg->control, bfin_read16(&reg->control) & ~CCR);

 	while (bfin_read16(&reg->status) & CCA) {
 		udelay(10);
 		if (--timeout == 0) {
 			dev_err(dev->dev.parent,
 					"fail to leave configuration mode\n");
 			BUG();
 		}
 	}

 	/*
 	 * clear _All_  tx and rx interrupts
 	 */
 	bfin_write16(&reg->mbtif1, 0xFFFF);
 	bfin_write16(&reg->mbtif2, 0xFFFF);
 	bfin_write16(&reg->mbrif1, 0xFFFF);
 	bfin_write16(&reg->mbrif2, 0xFFFF);

 	/*
 	 * clear global interrupt status register
 	 */
 	bfin_write16(&reg->gis, 0x7FF); /* overwrites with '1' */

 	/*
 	 * Initialize Interrupts
 	 * - set bits in the mailbox interrupt mask register
 	 * - global interrupt mask
 	 */
 	bfin_write16(&reg->mbim1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
 	bfin_write16(&reg->mbim2, BIT(TRANSMIT_CHL - 16));

 	bfin_write16(&reg->gim, EPIM | BOIM | RMLIM);
 	SSYNC();
 }

 static void bfin_can_start(struct net_device *dev)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);

 	/* enter reset mode */
 	if (priv->can.state != CAN_STATE_STOPPED)
 		bfin_can_set_reset_mode(dev);

 	/* leave reset mode */
 	bfin_can_set_normal_mode(dev);
 }

 static int bfin_can_set_mode(struct net_device *dev, enum can_mode mode)
 {
 	switch (mode) {
 	case CAN_MODE_START:
 		bfin_can_start(dev);
 		if (netif_queue_stopped(dev))
 			netif_wake_queue(dev);
 		break;

 	default:
 		return -EOPNOTSUPP;
 	}

 	return 0;
 }

 static int bfin_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	struct can_frame *cf = (struct can_frame *)skb->data;
 	u8 dlc = cf->can_dlc;
 	canid_t id = cf->can_id;
 	u8 *data = cf->data;
 	u16 val;
 	int i;

 	if (can_dropped_invalid_skb(dev, skb))
 		return NETDEV_TX_OK;

 	netif_stop_queue(dev);

 	/* fill id */
 	if (id & CAN_EFF_FLAG) {
 		bfin_write16(&reg->chl[TRANSMIT_CHL].id0, id);
 		if (id & CAN_RTR_FLAG)
 			writew(((id & 0x1FFF0000) >> 16) | IDE | AME | RTR,
 					&reg->chl[TRANSMIT_CHL].id1);
 		else
 			writew(((id & 0x1FFF0000) >> 16) | IDE | AME,
 					&reg->chl[TRANSMIT_CHL].id1);

 	} else {
 		if (id & CAN_RTR_FLAG)
 			writew((id << 2) | AME | RTR,
 				&reg->chl[TRANSMIT_CHL].id1);
 		else
 			bfin_write16(&reg->chl[TRANSMIT_CHL].id1,
 					(id << 2) | AME);
 	}

 	/* fill payload */
 	for (i = 0; i < 8; i += 2) {
 		val = ((7 - i) < dlc ? (data[7 - i]) : 0) +
 			((6 - i) < dlc ? (data[6 - i] << 8) : 0);
 		bfin_write16(&reg->chl[TRANSMIT_CHL].data[i], val);
 	}

 	/* fill data length code */
 	bfin_write16(&reg->chl[TRANSMIT_CHL].dlc, dlc);

 	can_put_echo_skb(skb, dev, 0);

 	/* set transmit request */
 	bfin_write16(&reg->trs2, BIT(TRANSMIT_CHL - 16));

 	return 0;
 }

 static void bfin_can_rx(struct net_device *dev, u16 isrc)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct net_device_stats *stats = &dev->stats;
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	struct can_frame *cf;
 	struct sk_buff *skb;
 	int obj;
 	int i;
 	u16 val;

 	skb = alloc_can_skb(dev, &cf);
 	if (skb == NULL)
 		return;

 	/* get id */
 	if (isrc & BIT(RECEIVE_EXT_CHL)) {
 		/* extended frame format (EFF) */
 		cf->can_id = ((bfin_read16(&reg->chl[RECEIVE_EXT_CHL].id1)
 			     & 0x1FFF) << 16)
 			     + bfin_read16(&reg->chl[RECEIVE_EXT_CHL].id0);
 		cf->can_id |= CAN_EFF_FLAG;
 		obj = RECEIVE_EXT_CHL;
 	} else {
 		/* standard frame format (SFF) */
 		cf->can_id = (bfin_read16(&reg->chl[RECEIVE_STD_CHL].id1)
 			     & 0x1ffc) >> 2;
 		obj = RECEIVE_STD_CHL;
 	}
 	if (bfin_read16(&reg->chl[obj].id1) & RTR)
 		cf->can_id |= CAN_RTR_FLAG;

 	/* get data length code */
 	cf->can_dlc = get_can_dlc(bfin_read16(&reg->chl[obj].dlc) & 0xF);

 	/* get payload */
 	for (i = 0; i < 8; i += 2) {
 		val = bfin_read16(&reg->chl[obj].data[i]);
 		cf->data[7 - i] = (7 - i) < cf->can_dlc ? val : 0;
 		cf->data[6 - i] = (6 - i) < cf->can_dlc ? (val >> 8) : 0;
 	}

 	netif_rx(skb);

 	stats->rx_packets++;
 	stats->rx_bytes += cf->can_dlc;
 }

 static int bfin_can_err(struct net_device *dev, u16 isrc, u16 status)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	struct net_device_stats *stats = &dev->stats;
 	struct can_frame *cf;
 	struct sk_buff *skb;
 	enum can_state state = priv->can.state;

 	skb = alloc_can_err_skb(dev, &cf);
 	if (skb == NULL)
 		return -ENOMEM;

 	if (isrc & RMLIS) {
 		/* data overrun interrupt */
 		dev_dbg(dev->dev.parent, "data overrun interrupt\n");
 		cf->can_id |= CAN_ERR_CRTL;
 		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 		stats->rx_over_errors++;
 		stats->rx_errors++;
 	}

 	if (isrc & BOIS) {
 		dev_dbg(dev->dev.parent, "bus-off mode interrupt\n");
 		state = CAN_STATE_BUS_OFF;
 		cf->can_id |= CAN_ERR_BUSOFF;
 		can_bus_off(dev);
 	}

 	if (isrc & EPIS) {
 		/* error passive interrupt */
 		dev_dbg(dev->dev.parent, "error passive interrupt\n");
 		state = CAN_STATE_ERROR_PASSIVE;
 	}

 	if ((isrc & EWTIS) || (isrc & EWRIS)) {
 		dev_dbg(dev->dev.parent,
 				"Error Warning Transmit/Receive Interrupt\n");
 		state = CAN_STATE_ERROR_WARNING;
 	}

 	if (state != priv->can.state && (state == CAN_STATE_ERROR_WARNING ||
 				state == CAN_STATE_ERROR_PASSIVE)) {
 		u16 cec = bfin_read16(&reg->cec);
 		u8 rxerr = cec;
 		u8 txerr = cec >> 8;

 		cf->can_id |= CAN_ERR_CRTL;
 		if (state == CAN_STATE_ERROR_WARNING) {
 			priv->can.can_stats.error_warning++;
 			cf->data[1] = (txerr > rxerr) ?
 				CAN_ERR_CRTL_TX_WARNING :
 				CAN_ERR_CRTL_RX_WARNING;
 		} else {
 			priv->can.can_stats.error_passive++;
 			cf->data[1] = (txerr > rxerr) ?
 				CAN_ERR_CRTL_TX_PASSIVE :
 				CAN_ERR_CRTL_RX_PASSIVE;
 		}
 	}

 	if (status) {
 		priv->can.can_stats.bus_error++;

 		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;

 		if (status & BEF)
 			cf->data[2] |= CAN_ERR_PROT_BIT;
 		else if (status & FER)
 			cf->data[2] |= CAN_ERR_PROT_FORM;
 		else if (status & SER)
 			cf->data[2] |= CAN_ERR_PROT_STUFF;
 		else
 			cf->data[2] |= CAN_ERR_PROT_UNSPEC;
 	}

 	priv->can.state = state;

 	netif_rx(skb);

 	stats->rx_packets++;
 	stats->rx_bytes += cf->can_dlc;

 	return 0;
 }

 irqreturn_t bfin_can_interrupt(int irq, void *dev_id)
 {
 	struct net_device *dev = dev_id;
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	struct net_device_stats *stats = &dev->stats;
 	u16 status, isrc;

 	if ((irq == priv->tx_irq) && bfin_read16(&reg->mbtif2)) {
 		/* transmission complete interrupt */
 		bfin_write16(&reg->mbtif2, 0xFFFF);
 		stats->tx_packets++;
 		stats->tx_bytes += bfin_read16(&reg->chl[TRANSMIT_CHL].dlc);
 		can_get_echo_skb(dev, 0);
 		netif_wake_queue(dev);
 	} else if ((irq == priv->rx_irq) && bfin_read16(&reg->mbrif1)) {
 		/* receive interrupt */
 		isrc = bfin_read16(&reg->mbrif1);
 		bfin_write16(&reg->mbrif1, 0xFFFF);
 		bfin_can_rx(dev, isrc);
 	} else if ((irq == priv->err_irq) && bfin_read16(&reg->gis)) {
 		/* error interrupt */
 		isrc = bfin_read16(&reg->gis);
 		status = bfin_read16(&reg->esr);
 		bfin_write16(&reg->gis, 0x7FF);
 		bfin_can_err(dev, isrc, status);
 	} else {
 		return IRQ_NONE;
 	}

 	return IRQ_HANDLED;
 }

 static int bfin_can_open(struct net_device *dev)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	int err;

 	/* set chip into reset mode */
 	bfin_can_set_reset_mode(dev);

 	/* common open */
 	err = open_candev(dev);
 	if (err)
 		goto exit_open;

 	/* register interrupt handler */
 	err = request_irq(priv->rx_irq, &bfin_can_interrupt, 0,
 			"bfin-can-rx", dev);
 	if (err)
 		goto exit_rx_irq;
 	err = request_irq(priv->tx_irq, &bfin_can_interrupt, 0,
 			"bfin-can-tx", dev);
 	if (err)
 		goto exit_tx_irq;
 	err = request_irq(priv->err_irq, &bfin_can_interrupt, 0,
 			"bfin-can-err", dev);
 	if (err)
 		goto exit_err_irq;

 	bfin_can_start(dev);

 	netif_start_queue(dev);

 	return 0;

 exit_err_irq:
 	free_irq(priv->tx_irq, dev);
 exit_tx_irq:
 	free_irq(priv->rx_irq, dev);
 exit_rx_irq:
 	close_candev(dev);
 exit_open:
 	return err;
 }

 static int bfin_can_close(struct net_device *dev)
 {
 	struct bfin_can_priv *priv = netdev_priv(dev);

 	netif_stop_queue(dev);
 	bfin_can_set_reset_mode(dev);

 	close_candev(dev);

 	free_irq(priv->rx_irq, dev);
 	free_irq(priv->tx_irq, dev);
 	free_irq(priv->err_irq, dev);

 	return 0;
 }

 struct net_device *alloc_bfin_candev(void)
 {
 	struct net_device *dev;
 	struct bfin_can_priv *priv;

 	dev = alloc_candev(sizeof(*priv), TX_ECHO_SKB_MAX);
 	if (!dev)
 		return NULL;

 	priv = netdev_priv(dev);

 	priv->dev = dev;
 	priv->can.bittiming_const = &bfin_can_bittiming_const;
 	priv->can.do_set_bittiming = bfin_can_set_bittiming;
 	priv->can.do_set_mode = bfin_can_set_mode;
 	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;

 	return dev;
 }

 static const struct net_device_ops bfin_can_netdev_ops = {
 	.ndo_open               = bfin_can_open,
 	.ndo_stop               = bfin_can_close,
 	.ndo_start_xmit         = bfin_can_start_xmit,
 };

 static int __devinit bfin_can_probe(struct platform_device *pdev)
 {
 	int err;
 	struct net_device *dev;
 	struct bfin_can_priv *priv;
 	struct resource *res_mem, *rx_irq, *tx_irq, *err_irq;
 	unsigned short *pdata;

 	pdata = pdev->dev.platform_data;
 	if (!pdata) {
 		dev_err(&pdev->dev, "No platform data provided!\n");
 		err = -EINVAL;
 		goto exit;
 	}

 	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	rx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	tx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
 	err_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 2);
 	if (!res_mem || !rx_irq || !tx_irq || !err_irq) {
 		err = -EINVAL;
 		goto exit;
 	}

 	if (!request_mem_region(res_mem->start, resource_size(res_mem),
 				dev_name(&pdev->dev))) {
 		err = -EBUSY;
 		goto exit;
 	}

 	/* request peripheral pins */
 	err = peripheral_request_list(pdata, dev_name(&pdev->dev));
 	if (err)
 		goto exit_mem_release;

 	dev = alloc_bfin_candev();
 	if (!dev) {
 		err = -ENOMEM;
 		goto exit_peri_pin_free;
 	}

 	priv = netdev_priv(dev);
 	priv->membase = (void __iomem *)res_mem->start;
 	priv->rx_irq = rx_irq->start;
 	priv->tx_irq = tx_irq->start;
 	priv->err_irq = err_irq->start;
 	priv->pin_list = pdata;
 	priv->can.clock.freq = get_sclk();

 	dev_set_drvdata(&pdev->dev, dev);
 	SET_NETDEV_DEV(dev, &pdev->dev);

 	dev->flags |= IFF_ECHO;	/* we support local echo */
 	dev->netdev_ops = &bfin_can_netdev_ops;

 	bfin_can_set_reset_mode(dev);

 	err = register_candev(dev);
 	if (err) {
 		dev_err(&pdev->dev, "registering failed (err=%d)\n", err);
 		goto exit_candev_free;
 	}

 	dev_info(&pdev->dev,
 		"%s device registered"
 		"(&reg_base=%p, rx_irq=%d, tx_irq=%d, err_irq=%d, sclk=%d)\n",
 		DRV_NAME, (void *)priv->membase, priv->rx_irq,
 		priv->tx_irq, priv->err_irq, priv->can.clock.freq);
 	return 0;

 exit_candev_free:
 	free_candev(dev);
 exit_peri_pin_free:
 	peripheral_free_list(pdata);
 exit_mem_release:
 	release_mem_region(res_mem->start, resource_size(res_mem));
 exit:
 	return err;
 }

 static int __devexit bfin_can_remove(struct platform_device *pdev)
 {
 	struct net_device *dev = dev_get_drvdata(&pdev->dev);
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct resource *res;

 	bfin_can_set_reset_mode(dev);

 	unregister_candev(dev);

 	dev_set_drvdata(&pdev->dev, NULL);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	release_mem_region(res->start, resource_size(res));

 	peripheral_free_list(priv->pin_list);

 	free_candev(dev);
 	return 0;
 }

 #ifdef CONFIG_PM
 static int bfin_can_suspend(struct platform_device *pdev, pm_message_t mesg)
 {
 	struct net_device *dev = dev_get_drvdata(&pdev->dev);
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;
 	int timeout = BFIN_CAN_TIMEOUT;

 	if (netif_running(dev)) {
 		/* enter sleep mode */
 		bfin_write16(&reg->control, bfin_read16(&reg->control) | SMR);
 		SSYNC();
 		while (!(bfin_read16(&reg->intr) & SMACK)) {
 			udelay(10);
 			if (--timeout == 0) {
 				dev_err(dev->dev.parent,
 						"fail to enter sleep mode\n");
 				BUG();
 			}
 		}
 	}

 	return 0;
 }

 static int bfin_can_resume(struct platform_device *pdev)
 {
 	struct net_device *dev = dev_get_drvdata(&pdev->dev);
 	struct bfin_can_priv *priv = netdev_priv(dev);
 	struct bfin_can_regs __iomem *reg = priv->membase;

 	if (netif_running(dev)) {
 		/* leave sleep mode */
 		bfin_write16(&reg->intr, 0);
 		SSYNC();
 	}

 	return 0;
 }
 #else
 #define bfin_can_suspend NULL
 #define bfin_can_resume NULL
 #endif	/* CONFIG_PM */

 static struct platform_driver bfin_can_driver = {
 	.probe = bfin_can_probe,
 	.remove = __devexit_p(bfin_can_remove),
 	.suspend = bfin_can_suspend,
 	.resume = bfin_can_resume,
 	.driver = {
 		.name = DRV_NAME,
 		.owner = THIS_MODULE,
 	},
 };

 static int __init bfin_can_init(void)
 {
 	return platform_driver_register(&bfin_can_driver);
 }
 module_init(bfin_can_init);

 static void __exit bfin_can_exit(void)
 {
 	platform_driver_unregister(&bfin_can_driver);
 }
 module_exit(bfin_can_exit);

 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Blackfin on-chip CAN netdevice driver");
	/*
	* Blackfin On-Chip CAN Driver
	*
	* Copyright 2004-2009 Analog Devices Inc.
	*
	* Enter bugs at http://blackfin.uclinux.org/
	*
	* Licensed under the GPL-2 or later.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/bitops.h>
	#include <linux/interrupt.h>
	#include <linux/errno.h>
	#include <linux/netdevice.h>
	#include <linux/skbuff.h>
	#include <linux/platform_device.h>

	#include <linux/can/dev.h>
	#include <linux/can/error.h>

	#include <asm/bfin_can.h>
	#include <asm/portmux.h>

	#define DRV_NAME "bfin_can"
	#define BFIN_CAN_TIMEOUT 100
	#define TX_ECHO_SKB_MAX 1

	/*
	* bfin can private data
	*/
	struct bfin_can_priv {
	struct can_priv can; /* must be the first member */
	struct net_device *dev;
	void __iomem *membase;
	int rx_irq;
	int tx_irq;
	int err_irq;
	unsigned short *pin_list;
	};

	/*
	* bfin can timing parameters
	*/
	static struct can_bittiming_const bfin_can_bittiming_const = {
	.name = DRV_NAME,
	.tseg1_min = 1,
	.tseg1_max = 16,
	.tseg2_min = 1,
	.tseg2_max = 8,
	.sjw_max = 4,
	/*
	* Although the BRP field can be set to any value, it is recommended
	* that the value be greater than or equal to 4, as restrictions
	* apply to the bit timing configuration when BRP is less than 4.
	*/
	.brp_min = 4,
	.brp_max = 1024,
	.brp_inc = 1,
	};

	static int bfin_can_set_bittiming(struct net_device *dev)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct can_bittiming *bt = &priv->can.bittiming;
	u16 clk, timing;

	clk = bt->brp - 1;
	timing = ((bt->sjw - 1) << 8) \| (bt->prop_seg + bt->phase_seg1 - 1) \|
	((bt->phase_seg2 - 1) << 4);

	/*
	* If the SAM bit is set, the input signal is oversampled three times
	* at the SCLK rate.
	*/
	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
	timing \|= SAM;

	bfin_write16(&reg->clock, clk);
	bfin_write16(&reg->timing, timing);

	dev_info(dev->dev.parent, "setting CLOCK=0x%04x TIMING=0x%04x\n",
	clk, timing);

	return 0;
	}

	static void bfin_can_set_reset_mode(struct net_device *dev)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	int timeout = BFIN_CAN_TIMEOUT;
	int i;

	/* disable interrupts */
	bfin_write16(&reg->mbim1, 0);
	bfin_write16(&reg->mbim2, 0);
	bfin_write16(&reg->gim, 0);

	/* reset can and enter configuration mode */
	bfin_write16(&reg->control, SRS \| CCR);
	SSYNC();
	bfin_write16(&reg->control, CCR);
	SSYNC();
	while (!(bfin_read16(&reg->control) & CCA)) {
	udelay(10);
	if (--timeout == 0) {
	dev_err(dev->dev.parent,
	"fail to enter configuration mode\n");
	BUG();
	}
	}

	/*
	* All mailbox configurations are marked as inactive
	* by writing to CAN Mailbox Configuration Registers 1 and 2
	* For all bits: 0 - Mailbox disabled, 1 - Mailbox enabled
	*/
	bfin_write16(&reg->mc1, 0);
	bfin_write16(&reg->mc2, 0);

	/* Set Mailbox Direction */
	bfin_write16(&reg->md1, 0xFFFF); /* mailbox 1-16 are RX */
	bfin_write16(&reg->md2, 0); /* mailbox 17-32 are TX */

	/* RECEIVE_STD_CHL */
	for (i = 0; i < 2; i++) {
	bfin_write16(&reg->chl[RECEIVE_STD_CHL + i].id0, 0);
	bfin_write16(&reg->chl[RECEIVE_STD_CHL + i].id1, AME);
	bfin_write16(&reg->chl[RECEIVE_STD_CHL + i].dlc, 0);
	bfin_write16(&reg->msk[RECEIVE_STD_CHL + i].amh, 0x1FFF);
	bfin_write16(&reg->msk[RECEIVE_STD_CHL + i].aml, 0xFFFF);
	}

	/* RECEIVE_EXT_CHL */
	for (i = 0; i < 2; i++) {
	bfin_write16(&reg->chl[RECEIVE_EXT_CHL + i].id0, 0);
	bfin_write16(&reg->chl[RECEIVE_EXT_CHL + i].id1, AME \| IDE);
	bfin_write16(&reg->chl[RECEIVE_EXT_CHL + i].dlc, 0);
	bfin_write16(&reg->msk[RECEIVE_EXT_CHL + i].amh, 0x1FFF);
	bfin_write16(&reg->msk[RECEIVE_EXT_CHL + i].aml, 0xFFFF);
	}

	bfin_write16(&reg->mc2, BIT(TRANSMIT_CHL - 16));
	bfin_write16(&reg->mc1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
	SSYNC();

	priv->can.state = CAN_STATE_STOPPED;
	}

	static void bfin_can_set_normal_mode(struct net_device *dev)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	int timeout = BFIN_CAN_TIMEOUT;

	/*
	* leave configuration mode
	*/
	bfin_write16(&reg->control, bfin_read16(&reg->control) & ~CCR);

	while (bfin_read16(&reg->status) & CCA) {
	udelay(10);
	if (--timeout == 0) {
	dev_err(dev->dev.parent,
	"fail to leave configuration mode\n");
	BUG();
	}
	}

	/*
	* clear _All_ tx and rx interrupts
	*/
	bfin_write16(&reg->mbtif1, 0xFFFF);
	bfin_write16(&reg->mbtif2, 0xFFFF);
	bfin_write16(&reg->mbrif1, 0xFFFF);
	bfin_write16(&reg->mbrif2, 0xFFFF);

	/*
	* clear global interrupt status register
	*/
	bfin_write16(&reg->gis, 0x7FF); /* overwrites with '1' */

	/*
	* Initialize Interrupts
	* - set bits in the mailbox interrupt mask register
	* - global interrupt mask
	*/
	bfin_write16(&reg->mbim1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
	bfin_write16(&reg->mbim2, BIT(TRANSMIT_CHL - 16));

	bfin_write16(&reg->gim, EPIM \| BOIM \| RMLIM);
	SSYNC();
	}

	static void bfin_can_start(struct net_device *dev)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);

	/* enter reset mode */
	if (priv->can.state != CAN_STATE_STOPPED)
	bfin_can_set_reset_mode(dev);

	/* leave reset mode */
	bfin_can_set_normal_mode(dev);
	}

	static int bfin_can_set_mode(struct net_device *dev, enum can_mode mode)
	{
	switch (mode) {
	case CAN_MODE_START:
	bfin_can_start(dev);
	if (netif_queue_stopped(dev))
	netif_wake_queue(dev);
	break;

	default:
	return -EOPNOTSUPP;
	}

	return 0;
	}

	static int bfin_can_start_xmit(struct sk_buff skb, struct net_device dev)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct can_frame cf = (struct can_frame )skb->data;
	u8 dlc = cf->can_dlc;
	canid_t id = cf->can_id;
	u8 *data = cf->data;
	u16 val;
	int i;

	if (can_dropped_invalid_skb(dev, skb))
	return NETDEV_TX_OK;

	netif_stop_queue(dev);

	/* fill id */
	if (id & CAN_EFF_FLAG) {
	bfin_write16(&reg->chl[TRANSMIT_CHL].id0, id);
	if (id & CAN_RTR_FLAG)
	writew(((id & 0x1FFF0000) >> 16) \| IDE \| AME \| RTR,
	&reg->chl[TRANSMIT_CHL].id1);
	else
	writew(((id & 0x1FFF0000) >> 16) \| IDE \| AME,
	&reg->chl[TRANSMIT_CHL].id1);

	} else {
	if (id & CAN_RTR_FLAG)
	writew((id << 2) \| AME \| RTR,
	&reg->chl[TRANSMIT_CHL].id1);
	else
	bfin_write16(&reg->chl[TRANSMIT_CHL].id1,
	(id << 2) \| AME);
	}

	/* fill payload */
	for (i = 0; i < 8; i += 2) {
	val = ((7 - i) < dlc ? (data[7 - i]) : 0) +
	((6 - i) < dlc ? (data[6 - i] << 8) : 0);
	bfin_write16(&reg->chl[TRANSMIT_CHL].data[i], val);
	}

	/* fill data length code */
	bfin_write16(&reg->chl[TRANSMIT_CHL].dlc, dlc);

	can_put_echo_skb(skb, dev, 0);

	/* set transmit request */
	bfin_write16(&reg->trs2, BIT(TRANSMIT_CHL - 16));

	return 0;
	}

	static void bfin_can_rx(struct net_device *dev, u16 isrc)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct net_device_stats *stats = &dev->stats;
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct can_frame *cf;
	struct sk_buff *skb;
	int obj;
	int i;
	u16 val;

	skb = alloc_can_skb(dev, &cf);
	if (skb == NULL)
	return;

	/* get id */
	if (isrc & BIT(RECEIVE_EXT_CHL)) {
	/* extended frame format (EFF) */
	cf->can_id = ((bfin_read16(&reg->chl[RECEIVE_EXT_CHL].id1)
	& 0x1FFF) << 16)
	+ bfin_read16(&reg->chl[RECEIVE_EXT_CHL].id0);
	cf->can_id \|= CAN_EFF_FLAG;
	obj = RECEIVE_EXT_CHL;
	} else {
	/* standard frame format (SFF) */
	cf->can_id = (bfin_read16(&reg->chl[RECEIVE_STD_CHL].id1)
	& 0x1ffc) >> 2;
	obj = RECEIVE_STD_CHL;
	}
	if (bfin_read16(&reg->chl[obj].id1) & RTR)
	cf->can_id \|= CAN_RTR_FLAG;

	/* get data length code */
	cf->can_dlc = get_can_dlc(bfin_read16(&reg->chl[obj].dlc) & 0xF);

	/* get payload */
	for (i = 0; i < 8; i += 2) {
	val = bfin_read16(&reg->chl[obj].data[i]);
	cf->data[7 - i] = (7 - i) < cf->can_dlc ? val : 0;
	cf->data[6 - i] = (6 - i) < cf->can_dlc ? (val >> 8) : 0;
	}

	netif_rx(skb);

	stats->rx_packets++;
	stats->rx_bytes += cf->can_dlc;
	}

	static int bfin_can_err(struct net_device *dev, u16 isrc, u16 status)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct net_device_stats *stats = &dev->stats;
	struct can_frame *cf;
	struct sk_buff *skb;
	enum can_state state = priv->can.state;

	skb = alloc_can_err_skb(dev, &cf);
	if (skb == NULL)
	return -ENOMEM;

	if (isrc & RMLIS) {
	/* data overrun interrupt */
	dev_dbg(dev->dev.parent, "data overrun interrupt\n");
	cf->can_id \|= CAN_ERR_CRTL;
	cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
	stats->rx_over_errors++;
	stats->rx_errors++;
	}

	if (isrc & BOIS) {
	dev_dbg(dev->dev.parent, "bus-off mode interrupt\n");
	state = CAN_STATE_BUS_OFF;
	cf->can_id \|= CAN_ERR_BUSOFF;
	can_bus_off(dev);
	}

	if (isrc & EPIS) {
	/* error passive interrupt */
	dev_dbg(dev->dev.parent, "error passive interrupt\n");
	state = CAN_STATE_ERROR_PASSIVE;
	}

	if ((isrc & EWTIS) \|\| (isrc & EWRIS)) {
	dev_dbg(dev->dev.parent,
	"Error Warning Transmit/Receive Interrupt\n");
	state = CAN_STATE_ERROR_WARNING;
	}

	if (state != priv->can.state && (state == CAN_STATE_ERROR_WARNING \|\|
	state == CAN_STATE_ERROR_PASSIVE)) {
	u16 cec = bfin_read16(&reg->cec);
	u8 rxerr = cec;
	u8 txerr = cec >> 8;

	cf->can_id \|= CAN_ERR_CRTL;
	if (state == CAN_STATE_ERROR_WARNING) {
	priv->can.can_stats.error_warning++;
	cf->data[1] = (txerr > rxerr) ?
	CAN_ERR_CRTL_TX_WARNING :
	CAN_ERR_CRTL_RX_WARNING;
	} else {
	priv->can.can_stats.error_passive++;
	cf->data[1] = (txerr > rxerr) ?
	CAN_ERR_CRTL_TX_PASSIVE :
	CAN_ERR_CRTL_RX_PASSIVE;
	}
	}

	if (status) {
	priv->can.can_stats.bus_error++;

	cf->can_id \|= CAN_ERR_PROT \| CAN_ERR_BUSERROR;

	if (status & BEF)
	cf->data[2] \|= CAN_ERR_PROT_BIT;
	else if (status & FER)
	cf->data[2] \|= CAN_ERR_PROT_FORM;
	else if (status & SER)
	cf->data[2] \|= CAN_ERR_PROT_STUFF;
	else
	cf->data[2] \|= CAN_ERR_PROT_UNSPEC;
	}

	priv->can.state = state;

	netif_rx(skb);

	stats->rx_packets++;
	stats->rx_bytes += cf->can_dlc;

	return 0;
	}

	irqreturn_t bfin_can_interrupt(int irq, void *dev_id)
	{
	struct net_device *dev = dev_id;
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct net_device_stats *stats = &dev->stats;
	u16 status, isrc;

	if ((irq == priv->tx_irq) && bfin_read16(&reg->mbtif2)) {
	/* transmission complete interrupt */
	bfin_write16(&reg->mbtif2, 0xFFFF);
	stats->tx_packets++;
	stats->tx_bytes += bfin_read16(&reg->chl[TRANSMIT_CHL].dlc);
	can_get_echo_skb(dev, 0);
	netif_wake_queue(dev);
	} else if ((irq == priv->rx_irq) && bfin_read16(&reg->mbrif1)) {
	/* receive interrupt */
	isrc = bfin_read16(&reg->mbrif1);
	bfin_write16(&reg->mbrif1, 0xFFFF);
	bfin_can_rx(dev, isrc);
	} else if ((irq == priv->err_irq) && bfin_read16(&reg->gis)) {
	/* error interrupt */
	isrc = bfin_read16(&reg->gis);
	status = bfin_read16(&reg->esr);
	bfin_write16(&reg->gis, 0x7FF);
	bfin_can_err(dev, isrc, status);
	} else {
	return IRQ_NONE;
	}

	return IRQ_HANDLED;
	}

	static int bfin_can_open(struct net_device *dev)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);
	int err;

	/* set chip into reset mode */
	bfin_can_set_reset_mode(dev);

	/* common open */
	err = open_candev(dev);
	if (err)
	goto exit_open;

	/* register interrupt handler */
	err = request_irq(priv->rx_irq, &bfin_can_interrupt, 0,
	"bfin-can-rx", dev);
	if (err)
	goto exit_rx_irq;
	err = request_irq(priv->tx_irq, &bfin_can_interrupt, 0,
	"bfin-can-tx", dev);
	if (err)
	goto exit_tx_irq;
	err = request_irq(priv->err_irq, &bfin_can_interrupt, 0,
	"bfin-can-err", dev);
	if (err)
	goto exit_err_irq;

	bfin_can_start(dev);

	netif_start_queue(dev);

	return 0;

	exit_err_irq:
	free_irq(priv->tx_irq, dev);
	exit_tx_irq:
	free_irq(priv->rx_irq, dev);
	exit_rx_irq:
	close_candev(dev);
	exit_open:
	return err;
	}

	static int bfin_can_close(struct net_device *dev)
	{
	struct bfin_can_priv *priv = netdev_priv(dev);

	netif_stop_queue(dev);
	bfin_can_set_reset_mode(dev);

	close_candev(dev);

	free_irq(priv->rx_irq, dev);
	free_irq(priv->tx_irq, dev);
	free_irq(priv->err_irq, dev);

	return 0;
	}

	struct net_device *alloc_bfin_candev(void)
	{
	struct net_device *dev;
	struct bfin_can_priv *priv;

	dev = alloc_candev(sizeof(*priv), TX_ECHO_SKB_MAX);
	if (!dev)
	return NULL;

	priv = netdev_priv(dev);

	priv->dev = dev;
	priv->can.bittiming_const = &bfin_can_bittiming_const;
	priv->can.do_set_bittiming = bfin_can_set_bittiming;
	priv->can.do_set_mode = bfin_can_set_mode;
	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;

	return dev;
	}

	static const struct net_device_ops bfin_can_netdev_ops = {
	.ndo_open = bfin_can_open,
	.ndo_stop = bfin_can_close,
	.ndo_start_xmit = bfin_can_start_xmit,
	};

	static int __devinit bfin_can_probe(struct platform_device *pdev)
	{
	int err;
	struct net_device *dev;
	struct bfin_can_priv *priv;
	struct resource res_mem, rx_irq, tx_irq, err_irq;
	unsigned short *pdata;

	pdata = pdev->dev.platform_data;
	if (!pdata) {
	dev_err(&pdev->dev, "No platform data provided!\n");
	err = -EINVAL;
	goto exit;
	}

	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	rx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	tx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
	err_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 2);
	if (!res_mem \|\| !rx_irq \|\| !tx_irq \|\| !err_irq) {
	err = -EINVAL;
	goto exit;
	}

	if (!request_mem_region(res_mem->start, resource_size(res_mem),
	dev_name(&pdev->dev))) {
	err = -EBUSY;
	goto exit;
	}

	/* request peripheral pins */
	err = peripheral_request_list(pdata, dev_name(&pdev->dev));
	if (err)
	goto exit_mem_release;

	dev = alloc_bfin_candev();
	if (!dev) {
	err = -ENOMEM;
	goto exit_peri_pin_free;
	}

	priv = netdev_priv(dev);
	priv->membase = (void __iomem *)res_mem->start;
	priv->rx_irq = rx_irq->start;
	priv->tx_irq = tx_irq->start;
	priv->err_irq = err_irq->start;
	priv->pin_list = pdata;
	priv->can.clock.freq = get_sclk();

	dev_set_drvdata(&pdev->dev, dev);
	SET_NETDEV_DEV(dev, &pdev->dev);

	dev->flags \|= IFF_ECHO; /* we support local echo */
	dev->netdev_ops = &bfin_can_netdev_ops;

	bfin_can_set_reset_mode(dev);

	err = register_candev(dev);
	if (err) {
	dev_err(&pdev->dev, "registering failed (err=%d)\n", err);
	goto exit_candev_free;
	}

	dev_info(&pdev->dev,
	"%s device registered"
	"(&reg_base=%p, rx_irq=%d, tx_irq=%d, err_irq=%d, sclk=%d)\n",
	DRV_NAME, (void *)priv->membase, priv->rx_irq,
	priv->tx_irq, priv->err_irq, priv->can.clock.freq);
	return 0;

	exit_candev_free:
	free_candev(dev);
	exit_peri_pin_free:
	peripheral_free_list(pdata);
	exit_mem_release:
	release_mem_region(res_mem->start, resource_size(res_mem));
	exit:
	return err;
	}

	static int __devexit bfin_can_remove(struct platform_device *pdev)
	{
	struct net_device *dev = dev_get_drvdata(&pdev->dev);
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct resource *res;

	bfin_can_set_reset_mode(dev);

	unregister_candev(dev);

	dev_set_drvdata(&pdev->dev, NULL);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(res->start, resource_size(res));

	peripheral_free_list(priv->pin_list);

	free_candev(dev);
	return 0;
	}

	#ifdef CONFIG_PM
	static int bfin_can_suspend(struct platform_device *pdev, pm_message_t mesg)
	{
	struct net_device *dev = dev_get_drvdata(&pdev->dev);
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	int timeout = BFIN_CAN_TIMEOUT;

	if (netif_running(dev)) {
	/* enter sleep mode */
	bfin_write16(&reg->control, bfin_read16(&reg->control) \| SMR);
	SSYNC();
	while (!(bfin_read16(&reg->intr) & SMACK)) {
	udelay(10);
	if (--timeout == 0) {
	dev_err(dev->dev.parent,
	"fail to enter sleep mode\n");
	BUG();
	}
	}
	}

	return 0;
	}

	static int bfin_can_resume(struct platform_device *pdev)
	{
	struct net_device *dev = dev_get_drvdata(&pdev->dev);
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;

	if (netif_running(dev)) {
	/* leave sleep mode */
	bfin_write16(&reg->intr, 0);
	SSYNC();
	}

	return 0;
	}
	#else
	#define bfin_can_suspend NULL
	#define bfin_can_resume NULL
	#endif /* CONFIG_PM */

	static struct platform_driver bfin_can_driver = {
	.probe = bfin_can_probe,
	.remove = __devexit_p(bfin_can_remove),
	.suspend = bfin_can_suspend,
	.resume = bfin_can_resume,
	.driver = {
	.name = DRV_NAME,
	.owner = THIS_MODULE,
	},
	};

	static int __init bfin_can_init(void)
	{
	return platform_driver_register(&bfin_can_driver);
	}
	module_init(bfin_can_init);

	static void __exit bfin_can_exit(void)
	{
	platform_driver_unregister(&bfin_can_driver);
	}
	module_exit(bfin_can_exit);

	MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Blackfin on-chip CAN netdevice driver");