Re: [PATCH v2 1/1] can: m_can: add Bosch M_CAN controller support

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On 07/04/2014 05:23 PM, Dong Aisheng wrote:
The patch adds the basic CAN TX/RX function support for Bosch M_CAN controller.
For TX, only one dedicated tx buffer is used for sending data.
For RX, RXFIFO 0 is used for receiving data to avoid overflow.
Rx FIFO 1 and Rx Buffers are not used currently, as well as Tx Event FIFO.

Due to the message ram can be shared by multi m_can instances
and the fifo element is configurable which is SoC dependant,
the design is to parse the message ram related configuration data from device
tree rather than hardcode define it in driver which can make the message
ram sharing fully transparent to M_CAN controller driver,
then we can gain better driver maintainability and future features upgrade.

M_CAN also supports CANFD protocol features like data payload up to 64 bytes
and bitrate switch at runtime, however, this patch still does not add the
support for these features.

Signed-off-by: Dong Aisheng <b29396@xxxxxxxxxxxxx>
---
Changes since v1:
Addressed all comments from Mark Rutland, Hartkopp and Marc Kleine-Budde
- merge three patches into one
- create directory drivers/net/can/m_can
- improve binding doc
- make sure using valid pointer before netif_receive_skb(skb)
- remove debug info a bit
- let the stats are updated even if alloc_can_err_skb() fails
- other small fixes

Test result:
Passed over night can-utils/canfdtest stress test on iMX6SX SDB board.

---
  .../devicetree/bindings/net/can/m_can.txt          |   65 ++
  drivers/net/can/Kconfig                            |    2 +
  drivers/net/can/Makefile                           |    1 +
  drivers/net/can/m_can/Kconfig                      |    4 +
  drivers/net/can/m_can/Makefile                     |    7 +
  drivers/net/can/m_can/m_can.c                      | 1136 ++++++++++++++++++++
  6 files changed, 1215 insertions(+), 0 deletions(-)
  create mode 100644 Documentation/devicetree/bindings/net/can/m_can.txt
  create mode 100644 drivers/net/can/m_can/Kconfig
  create mode 100644 drivers/net/can/m_can/Makefile
  create mode 100644 drivers/net/can/m_can/m_can.c

[...]

+static inline u32 m_can_read(const struct m_can_priv *priv, enum m_can_reg reg)
+{
+	return readl(priv->base + reg);
+}
+
+static inline void m_can_write(const struct m_can_priv *priv,
+				enum m_can_reg reg, u32 val)

Alignment should match open parenthesis....  :-)

+{
+	writel(val, priv->base + reg);
+}
+
+static inline void m_can_config_endisable(const struct m_can_priv *priv,
+				bool enable)

see above..

+{
+	u32 cccr = m_can_read(priv, M_CAN_CCCR);
+	u32 timeout = 10;
+	u32 val = 0;
+
+	if (enable) {
+		/* enable m_can configuration */
+		m_can_write(priv, M_CAN_CCCR, cccr | CCCR_INIT);
+		/* CCCR.CCE can only be set/reset while CCCR.INIT = '1' */
+		m_can_write(priv, M_CAN_CCCR, cccr | CCCR_INIT | CCCR_CCE);
+	} else {
+		m_can_write(priv, M_CAN_CCCR, cccr & ~(CCCR_INIT | CCCR_CCE));
+	}
+
+	/* there's a delay for module initialization */
+	if (enable)
+		val = CCCR_INIT | CCCR_CCE;
+
+	while ((m_can_read(priv, M_CAN_CCCR) & (CCCR_INIT | CCCR_CCE))
+				!= val) {
+		if (timeout == 0) {
+			netdev_warn(priv->dev, "Failed to init module\n");
+			return;
+		}
+		timeout--;
+		udelay(1);
+	}
+}
+
+static void m_can_enable_all_interrupts(const struct m_can_priv *priv)
+{
+	m_can_write(priv, M_CAN_ILE, ILE_EINT0 | ILE_EINT1);
+}
+
+static void m_can_disable_all_interrupts(const struct m_can_priv *priv)
+{
+	m_can_write(priv, M_CAN_ILE, 0x0);
+}
+
+static void m_can_read_fifo(const struct net_device *dev, struct can_frame *cf,
+				u32 rxfs)

same ..

+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	u32 flags, fgi;
+	void __iomem *fifo_addr;
+
+	fgi = (rxfs & RXFS_FGI_MASK) >> RXFS_FGI_OFF;
+	fifo_addr = priv->mram_base + priv->rxf0_off + fgi * RXF0_ELEMENT_SIZE;
+	flags = readl(fifo_addr);
+	if (flags & RX_BUF_XTD)
+		cf->can_id = (flags & CAN_EFF_MASK) | CAN_EFF_FLAG;
+	else
+		cf->can_id = (flags >> 18) & CAN_SFF_MASK;
+
+	if (flags & RX_BUF_RTR) {
+		cf->can_id |= CAN_RTR_FLAG;
+	} else {
+		flags = readl(fifo_addr + 0x4);
+		cf->can_dlc = get_can_dlc((flags >> 16) & 0x0F);
+		*(u32 *)(cf->data + 0) = readl(fifo_addr + 0x8);
+		*(u32 *)(cf->data + 4) = readl(fifo_addr + 0xC);
+	}
+
+	/* acknowledge rx fifo 0 */
+	m_can_write(priv, M_CAN_RXF0A, fgi);
+}
+
+static int m_can_do_rx_poll(struct net_device *dev, int quota)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	struct sk_buff *skb;
+	struct can_frame *frame;
+	u32 num_rx_pkts = 0;
+	u32 rxfs;
+
+	rxfs = m_can_read(priv, M_CAN_RXF0S);
+	if (!(rxfs & RXFS_FFL_MASK)) {
+		netdev_dbg(dev, "no messages in fifo0\n");
+		return 0;
+	}
+
+	while ((rxfs & RXFS_FFL_MASK) && (quota > 0)) {
+		if (rxfs & RXFS_RFL)
+			netdev_warn(dev, "Rx FIFO 0 Message Lost\n");
+
+		skb = alloc_can_skb(dev, &frame);
+		if (!skb) {
+			stats->rx_dropped++;
+			return 0;
+		}
+
+		m_can_read_fifo(dev, frame, rxfs);
+
+		stats->rx_packets++;
+		stats->rx_bytes += frame->can_dlc;
+
+		netif_receive_skb(skb);
+
+		quota--;
+		num_rx_pkts++;
+		rxfs = m_can_read(priv, M_CAN_RXF0S);
+	};
+
+	can_led_event(dev, CAN_LED_EVENT_RX);
+
+	return num_rx_pkts;
+}
+
+static int m_can_handle_lost_msg(struct net_device *dev)
+{
+	struct net_device_stats *stats = &dev->stats;
+	struct sk_buff *skb;
+	struct can_frame *frame;
+
+	netdev_err(dev, "msg lost in rxf0\n");
+
+	stats->rx_errors++;
+	stats->rx_over_errors++;
+
+	skb = alloc_can_err_skb(dev, &frame);
+	if (unlikely(!skb))
+		return 0;
+
+	frame->can_id |= CAN_ERR_CRTL;
+	frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+
+	netif_receive_skb(skb);
+
+	return 1;
+}
+
+static int m_can_handle_lec_err(struct net_device *dev,
+				enum m_can_lec_type lec_type)
+{
+	struct m_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 */
+	if (lec_type == LEC_UNUSED)
+		return 0;
+
+	priv->can.can_stats.bus_error++;
+	stats->rx_errors++;
+
+	/* propagate 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
+	 */

networking block comments don't use an empty /* line, use /* Comment

+	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[3] |= (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[3] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
+				CAN_ERR_PROT_LOC_CRC_DEL);
+		break;
+	default:
+		break;
+	}
+
+	stats->rx_packets++;
+	stats->rx_bytes += cf->can_dlc;
+	netif_receive_skb(skb);
+
+	return 1;
+}
+
+static int m_can_get_berr_counter(const struct net_device *dev,
+				  struct can_berr_counter *bec)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	unsigned int ecr;
+
+	clk_prepare_enable(priv->hclk);
+	clk_prepare_enable(priv->cclk);
+
+	ecr = m_can_read(priv, M_CAN_ECR);
+	bec->rxerr = (ecr & ECR_REC_MASK) >> ECR_REC_SHIFT;
+	bec->txerr = ecr & ECR_TEC_MASK;
+
+	clk_disable_unprepare(priv->hclk);
+	clk_disable_unprepare(priv->cclk);
+
+	return 0;
+}
+
+static int m_can_handle_state_change(struct net_device *dev,
+				enum can_state new_state)

Alignment should match open parenthesis

+{
+	struct m_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;
+	unsigned int ecr;
+
+	switch (new_state) {
+	case CAN_STATE_ERROR_ACTIVE:
+		/* error warning state */
+		priv->can.can_stats.error_warning++;
+		priv->can.state = CAN_STATE_ERROR_WARNING;
+		break;
+	case CAN_STATE_ERROR_PASSIVE:
+		/* error passive state */
+		priv->can.can_stats.error_passive++;
+		priv->can.state = CAN_STATE_ERROR_PASSIVE;
+		break;
+	case CAN_STATE_BUS_OFF:
+		/* bus-off state */
+		priv->can.state = CAN_STATE_BUS_OFF;
+		m_can_disable_all_interrupts(priv);
+		can_bus_off(dev);
+		break;
+	default:
+		break;
+	}
+
+	/* propagate the error condition to the CAN stack */
+	skb = alloc_can_err_skb(dev, &cf);
+	if (unlikely(!skb))
+		return 0;
+
+	m_can_get_berr_counter(dev, &bec);
+
+	switch (new_state) {
+	case CAN_STATE_ERROR_ACTIVE:
+		/* error warning state */
+		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 CAN_STATE_ERROR_PASSIVE:
+		/* error passive state */
+		cf->can_id |= CAN_ERR_CRTL;
+		ecr = m_can_read(priv, M_CAN_ECR);
+		if (ecr & ECR_RP)
+			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 CAN_STATE_BUS_OFF:
+		/* bus-off state */
+		cf->can_id |= CAN_ERR_BUSOFF;
+		break;
+	default:
+		break;
+	}
+
+	stats->rx_packets++;
+	stats->rx_bytes += cf->can_dlc;
+	netif_receive_skb(skb);
+
+	return 1;
+}
+
+static int m_can_handle_state_errors(struct net_device *dev, u32 psr)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	int work_done = 0;
+
+	if ((psr & PSR_EW) &&
+		(priv->can.state != CAN_STATE_ERROR_WARNING))

Alignment should match open parenthesis

  {
+		netdev_dbg(dev, "entered error warning state\n");
+		work_done += m_can_handle_state_change(dev,
+				CAN_STATE_ERROR_WARNING);
+	}
+
+	if ((psr & PSR_EP) &&
+		(priv->can.state != CAN_STATE_ERROR_PASSIVE))

Alignment should match open parenthesis

  {
+		netdev_dbg(dev, "entered error warning state\n");
+		work_done += m_can_handle_state_change(dev,
+				CAN_STATE_ERROR_PASSIVE);
+	}
+
+	if ((psr & PSR_BO) &&
+		(priv->can.state != CAN_STATE_BUS_OFF))

Alignment should match open parenthesis

  {
+		netdev_dbg(dev, "entered error warning state\n");
+		work_done += m_can_handle_state_change(dev,
+				CAN_STATE_BUS_OFF);
+	}
+
+	return work_done;
+}
+
+static int m_can_handle_bus_errors(struct net_device *dev, u32 irqstatus,
+							u32 psr)

Alignment should match open parenthesis

+{
+	int work_done = 0;
+
+	if (irqstatus & IR_RF0L)
+		work_done += m_can_handle_lost_msg(dev);
+
+	/* handle lec errors on the bus */
+	if (psr & LEC_UNUSED)
+		work_done += m_can_handle_lec_err(dev,
+				psr & LEC_UNUSED);
+
+	/* other unproccessed error interrupts */
+	if (irqstatus & IR_WDI)
+		netdev_err(dev, "Message RAM Watchdog event due to missing READY\n");
+	if (irqstatus & IR_TOO)
+		netdev_err(dev, "Timeout reached\n");
+	if (irqstatus & IR_MRAF)
+		netdev_err(dev, "Message RAM access failure occurred\n");
+
+	return work_done;
+}
+
+static int m_can_poll(struct napi_struct *napi, int quota)
+{
+	struct net_device *dev = napi->dev;
+	struct m_can_priv *priv = netdev_priv(dev);
+	int work_done = 0;
+	u32 irqstatus, psr;
+
+	irqstatus = priv->irqstatus | m_can_read(priv, M_CAN_IR);
+	if (!irqstatus)
+		goto end;
+
+	psr = m_can_read(priv, M_CAN_PSR);
+	if (irqstatus & IR_ERR_STATE)
+		work_done += m_can_handle_state_errors(dev, psr);
+
+	if (irqstatus & IR_ERR_BUS)
+		work_done += m_can_handle_bus_errors(dev, irqstatus, psr);
+
+	if (irqstatus & IR_RF0N)
+		/* handle events corresponding to receive message objects */
+		work_done += m_can_do_rx_poll(dev, (quota - work_done));
+
+	if (work_done < quota) {
+		napi_complete(napi);
+		m_can_enable_all_interrupts(priv);
+	}
+
+end:
+	return work_done;
+}
+
+static irqreturn_t m_can_isr(int irq, void *dev_id)
+{
+	struct net_device *dev = (struct net_device *)dev_id;
+	struct m_can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	u32 ir;
+
+	ir = m_can_read(priv, M_CAN_IR);
+	if (!ir)
+		return IRQ_NONE;
+
+	/* ACK all irqs */
+	if (ir & IR_ALL_INT)
+		m_can_write(priv, M_CAN_IR, ir);
+
+	/*
+	 * schedule NAPI in case of
+	 * - rx IRQ
+	 * - state change IRQ
+	 * - bus error IRQ and bus error reporting
+	 */

networking block comments don't use an empty /* line, use /* Comment

+	if ((ir & IR_RF0N) || (ir & IR_ERR_ALL)) {
+		priv->irqstatus = ir;
+		m_can_disable_all_interrupts(priv);
+		napi_schedule(&priv->napi);
+	}
+
+	/* transmission complete interrupt */
+	if (ir & IR_TC) {
+		stats->tx_bytes += can_get_echo_skb(dev, 0);
+		stats->tx_packets++;
+		can_led_event(dev, CAN_LED_EVENT_TX);
+		netif_wake_queue(dev);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static const struct can_bittiming_const m_can_bittiming_const = {
+	.name = KBUILD_MODNAME,
+	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
+	.tseg1_max = 64,
+	.tseg2_min = 1,		/* Time segment 2 = phase_seg2 */
+	.tseg2_max = 16,
+	.sjw_max = 16,
+	.brp_min = 1,
+	.brp_max = 1024,
+	.brp_inc = 1,
+};
+
+static int m_can_set_bittiming(struct net_device *dev)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	const struct can_bittiming *bt = &priv->can.bittiming;
+	u16 brp, sjw, tseg1, tseg2;
+	u32 reg_btp;
+
+	brp = bt->brp - 1;
+	sjw = bt->sjw - 1;
+	tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
+	tseg2 = bt->phase_seg2 - 1;
+	reg_btp = (brp << BTR_BRP_SHIFT) | (sjw << BTR_SJW_SHIFT) |
+			(tseg1 << BTR_TSEG1_SHIFT) | (tseg2 << BTR_TSEG2_SHIFT);
+	m_can_write(priv, M_CAN_BTP, reg_btp);
+	netdev_dbg(dev, "setting BTP 0x%x\n", reg_btp);
+
+	return 0;
+}
+
+/*
+ * Configure M_CAN chip:
+ * - set rx buffer/fifo element size
+ * - configure rx fifo
+ * - accept non-matching frame into fifo 0
+ * - configure tx buffer
+ * - configure mode
+ * - setup bittiming
+ */

networking block comments don't use an empty /* line, use /* Comment

+static void m_can_chip_config(struct net_device *dev)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	u32 cccr, test;
+
+	m_can_config_endisable(priv, true);
+
+	/* RX Buffer/FIFO Element Size 8 bytes data field */
+	m_can_write(priv, M_CAN_RXESC, M_CAN_RXESC_8BYTES);
+
+	/* Accept Non-matching Frames Into FIFO 0 */
+	m_can_write(priv, M_CAN_GFC, 0x0);
+
+	/* only support one Tx Buffer currently */
+	m_can_write(priv, M_CAN_TXBC, (1 << TXBC_NDTB_OFF) |
+		(priv->mram_off + priv->txb_off));
+
+	/* only support 8 bytes firstly */
+	m_can_write(priv, M_CAN_TXESC, TXESC_TBDS_8BYTES);
+
+	m_can_write(priv, M_CAN_TXEFC, 0x00010000 |
+		(priv->mram_off + priv->txe_off));
+
+	/* rx fifo configuration, blocking mode, fifo size 1 */
+	m_can_write(priv, M_CAN_RXF0C, (priv->rxf0_elems << RXFC_FS_OFF) |
+		RXFC_FWM_1 | (priv->mram_off + priv->rxf0_off));
+
+	m_can_write(priv, M_CAN_RXF1C, (priv->rxf1_elems << RXFC_FS_OFF) |
+		RXFC_FWM_1 | (priv->mram_off + priv->rxf1_off));
+
+	cccr = m_can_read(priv, M_CAN_CCCR);
+	cccr &= ~(CCCR_TEST | CCCR_MON);
+	test = m_can_read(priv, M_CAN_TEST);
+	test &= ~TEST_LBCK;
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		cccr |= CCCR_MON;
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
+		cccr |= CCCR_TEST;
+		test |= TEST_LBCK;
+	}
+
+	m_can_write(priv, M_CAN_CCCR, cccr);
+	m_can_write(priv, M_CAN_TEST, test);
+
+	/* enable all interrupts */
+	m_can_write(priv, M_CAN_IR, IR_ALL_INT);
+	m_can_write(priv, M_CAN_IE, IR_ALL_INT);
+	/* route all interrupts to INT0 */
+	m_can_write(priv, M_CAN_ILS, ILS_ALL_INT0);
+
+	/* set bittiming params */
+	m_can_set_bittiming(dev);
+
+	m_can_config_endisable(priv, false);
+}
+
+static void m_can_start(struct net_device *dev)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+
+	/* basic m_can configuration */
+	m_can_chip_config(dev);
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	m_can_enable_all_interrupts(priv);
+}
+
+static int m_can_set_mode(struct net_device *dev, enum can_mode mode)
+{
+	switch (mode) {
+	case CAN_MODE_START:
+		m_can_start(dev);
+		netif_wake_queue(dev);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static void free_m_can_dev(struct net_device *dev)
+{
+	free_candev(dev);
+}
+
+static struct net_device *alloc_m_can_dev(void)
+{
+	struct net_device *dev;
+	struct m_can_priv *priv;
+
+	dev = alloc_candev(sizeof(struct m_can_priv), 1);
+	if (!dev)
+		return NULL;
+
+	priv = netdev_priv(dev);
+	netif_napi_add(dev, &priv->napi, m_can_poll, M_CAN_NAPI_WEIGHT);
+
+	priv->dev = dev;
+	priv->can.bittiming_const = &m_can_bittiming_const;
+	priv->can.do_set_mode = m_can_set_mode;
+	priv->can.do_get_berr_counter = m_can_get_berr_counter;
+	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
+					CAN_CTRLMODE_LISTENONLY |
+					CAN_CTRLMODE_BERR_REPORTING;
+
+	return dev;
+}
+
+static int m_can_open(struct net_device *dev)
+{
+	int err;
+	struct m_can_priv *priv = netdev_priv(dev);
+
+	clk_prepare_enable(priv->hclk);
+	clk_prepare_enable(priv->cclk);
+
+	/* open the can device */
+	err = open_candev(dev);
+	if (err) {
+		netdev_err(dev, "failed to open can device\n");
+		goto exit_open_fail;
+	}
+
+	/* register interrupt handler */
+	err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
+				dev);

Alignment should match open parenthesis

+	if (err < 0) {
+		netdev_err(dev, "failed to request interrupt\n");
+		goto exit_irq_fail;
+	}
+
+	/* start the m_can controller */
+	m_can_start(dev);
+
+	can_led_event(dev, CAN_LED_EVENT_OPEN);
+	napi_enable(&priv->napi);
+	netif_start_queue(dev);
+
+	return 0;
+
+exit_irq_fail:
+	close_candev(dev);
+exit_open_fail:
+	clk_disable_unprepare(priv->hclk);
+	clk_disable_unprepare(priv->cclk);
+	return err;
+}
+
+static void m_can_stop(struct net_device *dev)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+
+	/* disable all interrupts */
+	m_can_disable_all_interrupts(priv);
+
+	clk_disable_unprepare(priv->hclk);
+	clk_disable_unprepare(priv->cclk);
+
+	/* set the state as STOPPED */
+	priv->can.state = CAN_STATE_STOPPED;
+}
+
+static int m_can_close(struct net_device *dev)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+
+	netif_stop_queue(dev);
+	napi_disable(&priv->napi);
+	m_can_stop(dev);
+	free_irq(dev->irq, dev);
+	close_candev(dev);
+	can_led_event(dev, CAN_LED_EVENT_STOP);
+
+	return 0;
+}
+
+static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
+					struct net_device *dev)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	u32 flags = 0, id;
+	void __iomem *fifo_addr;
+
+	if (can_dropped_invalid_skb(dev, skb))
+		return NETDEV_TX_OK;
+
+	netif_stop_queue(dev);
+
+	if (cf->can_id & CAN_RTR_FLAG)
+		flags |= TX_BUF_RTR;
+
+	if (cf->can_id & CAN_EFF_FLAG) {
+		id = cf->can_id & CAN_EFF_MASK;
+		flags |= TX_BUF_XTD;
+	} else {
+		id = ((cf->can_id & CAN_SFF_MASK) << 18);
+	}
+
+	/* message ram configuration */
+	fifo_addr = priv->mram_base + priv->mram_off + priv->txb_off;
+	writel(id | flags, fifo_addr);
+	writel(cf->can_dlc << 16, fifo_addr + 0x4);
+	writel(*(u32 *)(cf->data + 0), fifo_addr + 0x8);
+	writel(*(u32 *)(cf->data + 4), fifo_addr + 0xc);
+
+	can_put_echo_skb(skb, dev, 0);
+
+	/* enable first TX buffer to start transfer  */
+	m_can_write(priv, M_CAN_TXBTIE, 0x1);
+	m_can_write(priv, M_CAN_TXBAR, 0x1);
+
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops m_can_netdev_ops = {
+	.ndo_open = m_can_open,
+	.ndo_stop = m_can_close,
+	.ndo_start_xmit = m_can_start_xmit,
+};
+
+static int register_m_can_dev(struct net_device *dev)
+{
+	dev->flags |= IFF_ECHO;	/* we support local echo */
+	dev->netdev_ops = &m_can_netdev_ops;
+
+	return register_candev(dev);
+}
+
+static const struct of_device_id m_can_of_table[] = {
+	{ .compatible = "bosch,m_can", .data = NULL },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, m_can_of_table);
+
+static int m_can_of_parse_mram(struct platform_device *pdev,
+				struct m_can_priv *priv)

Alignment should match open parenthesis

+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *res;
+	void __iomem *addr;
+	u32 out_val[MRAM_CFG_LEN];
+	int ret;
+
+	/* message ram could be shared */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram");
+	if (!res)
+		return -ENODEV;
+
+	addr = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+	if (!addr)
+		return -ENODEV;
+
+	/* get message ram configuration */
+	ret = of_property_read_u32_array(np, "mram-cfg",
+				out_val, sizeof(out_val) / 4);

Alignment should match open parenthesis

+	if (ret) {
+		dev_err(&pdev->dev, "can not get message ram configuration\n");
+		return -ENODEV;
+	}
+
+	priv->mram_base = addr;
+	priv->mram_off = out_val[0];
+	priv->sidf_elems = out_val[1];
+	priv->sidf_off = priv->mram_off;
+	priv->xidf_elems = out_val[2];
+	priv->xidf_off = priv->sidf_off + priv->sidf_elems * SIDF_ELEMENT_SIZE;
+	priv->rxf0_elems = out_val[3] & RXFC_FS_MASK;
+	priv->rxf0_off = priv->xidf_off + priv->xidf_elems * XIDF_ELEMENT_SIZE;
+	priv->rxf1_elems = out_val[4] & RXFC_FS_MASK;
+	priv->rxf1_off = priv->rxf0_off + priv->rxf0_elems * RXF0_ELEMENT_SIZE;
+	priv->rxb_elems = out_val[5];
+	priv->rxb_off = priv->rxf1_off + priv->rxf1_elems * RXF1_ELEMENT_SIZE;
+	priv->txe_elems = out_val[6];
+	priv->txe_off = priv->rxb_off + priv->rxb_elems * RXB_ELEMENT_SIZE;
+	priv->txb_elems = out_val[7] & TXBC_NDTB_MASK;
+	priv->txb_off = priv->txe_off + priv->txe_elems * TXE_ELEMENT_SIZE;
+
+	dev_dbg(&pdev->dev, "mram_base =%p mram_off =0x%x "
+		"sidf %d xidf %d rxf0 %d rxf1 %d rxb %d txe %d txb %d\n",
+		priv->mram_base, priv->mram_off, priv->sidf_elems,
+		priv->xidf_elems, priv->rxf0_elems, priv->rxf1_elems,
+		priv->rxb_elems, priv->txe_elems, priv->txb_elems);

quoted string split across lines...

--
Cheers,
Varka Bhadram.

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