1 files changed, 167 insertions, 99 deletions

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 43bca315a66c..2470c47b2e31 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -21,6 +21,7 @@
 #include <linux/iopoll.h>
 #include <linux/can/dev.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/phy/phy.h>
 
 #include "m_can.h"
 
@@ -278,7 +279,7 @@ enum m_can_reg {
 /* Message RAM Elements */
 #define M_CAN_FIFO_ID		0x0
 #define M_CAN_FIFO_DLC		0x4
-#define M_CAN_FIFO_DATA(n)	(0x8 + ((n) << 2))
+#define M_CAN_FIFO_DATA		0x8
 
 /* Rx Buffer Element */
 /* R0 */
@@ -308,6 +309,15 @@ enum m_can_reg {
 #define TX_EVENT_MM_MASK	GENMASK(31, 24)
 #define TX_EVENT_TXTS_MASK	GENMASK(15, 0)
 
+/* The ID and DLC registers are adjacent in M_CAN FIFO memory,
+ * and we can save a (potentially slow) bus round trip by combining
+ * reads and writes to them.
+ */
+struct id_and_dlc {
+	u32 id;
+	u32 dlc;
+};
+
 static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg)
 {
 	return cdev->ops->read_reg(cdev, reg);
@@ -319,36 +329,39 @@ static inline void m_can_write(struct m_can_classdev *cdev, enum m_can_reg reg,
 	cdev->ops->write_reg(cdev, reg, val);
 }
 
-static u32 m_can_fifo_read(struct m_can_classdev *cdev,
-			   u32 fgi, unsigned int offset)
+static int
+m_can_fifo_read(struct m_can_classdev *cdev,
+		u32 fgi, unsigned int offset, void *val, size_t val_count)
 {
 	u32 addr_offset = cdev->mcfg[MRAM_RXF0].off + fgi * RXF0_ELEMENT_SIZE +
 		offset;
 
-	return cdev->ops->read_fifo(cdev, addr_offset);
+	return cdev->ops->read_fifo(cdev, addr_offset, val, val_count);
 }
 
-static void m_can_fifo_write(struct m_can_classdev *cdev,
-			     u32 fpi, unsigned int offset, u32 val)
+static int
+m_can_fifo_write(struct m_can_classdev *cdev,
+		 u32 fpi, unsigned int offset, const void *val, size_t val_count)
 {
 	u32 addr_offset = cdev->mcfg[MRAM_TXB].off + fpi * TXB_ELEMENT_SIZE +
 		offset;
 
-	cdev->ops->write_fifo(cdev, addr_offset, val);
+	return cdev->ops->write_fifo(cdev, addr_offset, val, val_count);
 }
 
-static inline void m_can_fifo_write_no_off(struct m_can_classdev *cdev,
-					   u32 fpi, u32 val)
+static inline int m_can_fifo_write_no_off(struct m_can_classdev *cdev,
+					  u32 fpi, u32 val)
 {
-	cdev->ops->write_fifo(cdev, fpi, val);
+	return cdev->ops->write_fifo(cdev, fpi, &val, 1);
 }
 
-static u32 m_can_txe_fifo_read(struct m_can_classdev *cdev, u32 fgi, u32 offset)
+static int
+m_can_txe_fifo_read(struct m_can_classdev *cdev, u32 fgi, u32 offset, u32 *val)
 {
 	u32 addr_offset = cdev->mcfg[MRAM_TXE].off + fgi * TXE_ELEMENT_SIZE +
 		offset;
 
-	return cdev->ops->read_fifo(cdev, addr_offset);
+	return cdev->ops->read_fifo(cdev, addr_offset, val, 1);
 }
 
 static inline bool m_can_tx_fifo_full(struct m_can_classdev *cdev)
@@ -436,7 +449,7 @@ static void m_can_clean(struct net_device *net)
  * napi. For non-peripherals, RX is done in napi already, so push
  * directly. timestamp is used to ensure good skb ordering in
  * rx-offload and is ignored for non-peripherals.
-*/
+ */
 static void m_can_receive_skb(struct m_can_classdev *cdev,
 			      struct sk_buff *skb,
 			      u32 timestamp)
@@ -454,54 +467,57 @@ static void m_can_receive_skb(struct m_can_classdev *cdev,
 	}
 }
 
-static void m_can_read_fifo(struct net_device *dev, u32 rxfs)
+static int m_can_read_fifo(struct net_device *dev, u32 rxfs)
 {
 	struct net_device_stats *stats = &dev->stats;
 	struct m_can_classdev *cdev = netdev_priv(dev);
 	struct canfd_frame *cf;
 	struct sk_buff *skb;
-	u32 id, fgi, dlc;
+	struct id_and_dlc fifo_header;
+	u32 fgi;
 	u32 timestamp = 0;
-	int i;
+	int err;
 
 	/* calculate the fifo get index for where to read data */
 	fgi = FIELD_GET(RXFS_FGI_MASK, rxfs);
-	dlc = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DLC);
-	if (dlc & RX_BUF_FDF)
+	err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_ID, &fifo_header, 2);
+	if (err)
+		goto out_fail;
+
+	if (fifo_header.dlc & RX_BUF_FDF)
 		skb = alloc_canfd_skb(dev, &cf);
 	else
 		skb = alloc_can_skb(dev, (struct can_frame **)&cf);
 	if (!skb) {
 		stats->rx_dropped++;
-		return;
+		return 0;
 	}
 
-	if (dlc & RX_BUF_FDF)
-		cf->len = can_fd_dlc2len((dlc >> 16) & 0x0F);
+	if (fifo_header.dlc & RX_BUF_FDF)
+		cf->len = can_fd_dlc2len((fifo_header.dlc >> 16) & 0x0F);
 	else
-		cf->len = can_cc_dlc2len((dlc >> 16) & 0x0F);
+		cf->len = can_cc_dlc2len((fifo_header.dlc >> 16) & 0x0F);
 
-	id = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_ID);
-	if (id & RX_BUF_XTD)
-		cf->can_id = (id & CAN_EFF_MASK) | CAN_EFF_FLAG;
+	if (fifo_header.id & RX_BUF_XTD)
+		cf->can_id = (fifo_header.id & CAN_EFF_MASK) | CAN_EFF_FLAG;
 	else
-		cf->can_id = (id >> 18) & CAN_SFF_MASK;
+		cf->can_id = (fifo_header.id >> 18) & CAN_SFF_MASK;
 
-	if (id & RX_BUF_ESI) {
+	if (fifo_header.id & RX_BUF_ESI) {
 		cf->flags |= CANFD_ESI;
 		netdev_dbg(dev, "ESI Error\n");
 	}
 
-	if (!(dlc & RX_BUF_FDF) && (id & RX_BUF_RTR)) {
+	if (!(fifo_header.dlc & RX_BUF_FDF) && (fifo_header.id & RX_BUF_RTR)) {
 		cf->can_id |= CAN_RTR_FLAG;
 	} else {
-		if (dlc & RX_BUF_BRS)
+		if (fifo_header.dlc & RX_BUF_BRS)
 			cf->flags |= CANFD_BRS;
 
-		for (i = 0; i < cf->len; i += 4)
-			*(u32 *)(cf->data + i) =
-				m_can_fifo_read(cdev, fgi,
-						M_CAN_FIFO_DATA(i / 4));
+		err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DATA,
+				      cf->data, DIV_ROUND_UP(cf->len, 4));
+		if (err)
+			goto out_fail;
 	}
 
 	/* acknowledge rx fifo 0 */
@@ -510,9 +526,15 @@ static void m_can_read_fifo(struct net_device *dev, u32 rxfs)
 	stats->rx_packets++;
 	stats->rx_bytes += cf->len;
 
-	timestamp = FIELD_GET(RX_BUF_RXTS_MASK, dlc);
+	timestamp = FIELD_GET(RX_BUF_RXTS_MASK, fifo_header.dlc);
 
 	m_can_receive_skb(cdev, skb, timestamp);
+
+	return 0;
+
+out_fail:
+	netdev_err(dev, "FIFO read returned %d\n", err);
+	return err;
 }
 
 static int m_can_do_rx_poll(struct net_device *dev, int quota)
@@ -520,6 +542,7 @@ static int m_can_do_rx_poll(struct net_device *dev, int quota)
 	struct m_can_classdev *cdev = netdev_priv(dev);
 	u32 pkts = 0;
 	u32 rxfs;
+	int err;
 
 	rxfs = m_can_read(cdev, M_CAN_RXF0S);
 	if (!(rxfs & RXFS_FFL_MASK)) {
@@ -528,7 +551,9 @@ static int m_can_do_rx_poll(struct net_device *dev, int quota)
 	}
 
 	while ((rxfs & RXFS_FFL_MASK) && (quota > 0)) {
-		m_can_read_fifo(dev, rxfs);
+		err = m_can_read_fifo(dev, rxfs);
+		if (err)
+			return err;
 
 		quota--;
 		pkts++;
@@ -874,6 +899,7 @@ static int m_can_handle_bus_errors(struct net_device *dev, u32 irqstatus,
 static int m_can_rx_handler(struct net_device *dev, int quota)
 {
 	struct m_can_classdev *cdev = netdev_priv(dev);
+	int rx_work_or_err;
 	int work_done = 0;
 	u32 irqstatus, psr;
 
@@ -910,8 +936,13 @@ static int m_can_rx_handler(struct net_device *dev, int quota)
 	if (irqstatus & IR_ERR_BUS_30X)
 		work_done += m_can_handle_bus_errors(dev, irqstatus, psr);
 
-	if (irqstatus & IR_RF0N)
-		work_done += m_can_do_rx_poll(dev, (quota - work_done));
+	if (irqstatus & IR_RF0N) {
+		rx_work_or_err = m_can_do_rx_poll(dev, (quota - work_done));
+		if (rx_work_or_err < 0)
+			return rx_work_or_err;
+
+		work_done += rx_work_or_err;
+	}
 end:
 	return work_done;
 }
@@ -919,12 +950,17 @@ end:
 static int m_can_rx_peripheral(struct net_device *dev)
 {
 	struct m_can_classdev *cdev = netdev_priv(dev);
+	int work_done;
 
-	m_can_rx_handler(dev, M_CAN_NAPI_WEIGHT);
+	work_done = m_can_rx_handler(dev, M_CAN_NAPI_WEIGHT);
 
-	m_can_enable_all_interrupts(cdev);
+	/* Don't re-enable interrupts if the driver had a fatal error
+	 * (e.g., FIFO read failure).
+	 */
+	if (work_done >= 0)
+		m_can_enable_all_interrupts(cdev);
 
-	return 0;
+	return work_done;
 }
 
 static int m_can_poll(struct napi_struct *napi, int quota)
@@ -934,7 +970,11 @@ static int m_can_poll(struct napi_struct *napi, int quota)
 	int work_done;
 
 	work_done = m_can_rx_handler(dev, quota);
-	if (work_done < quota) {
+
+	/* Don't re-enable interrupts if the driver had a fatal error
+	 * (e.g., FIFO read failure).
+	 */
+	if (work_done >= 0 && work_done < quota) {
 		napi_complete_done(napi, work_done);
 		m_can_enable_all_interrupts(cdev);
 	}
@@ -945,7 +985,7 @@ static int m_can_poll(struct napi_struct *napi, int quota)
 /* Echo tx skb and update net stats. Peripherals use rx-offload for
  * echo. timestamp is used for peripherals to ensure correct ordering
  * by rx-offload, and is ignored for non-peripherals.
-*/
+ */
 static void m_can_tx_update_stats(struct m_can_classdev *cdev,
 				  unsigned int msg_mark,
 				  u32 timestamp)
@@ -965,7 +1005,7 @@ static void m_can_tx_update_stats(struct m_can_classdev *cdev,
 	stats->tx_packets++;
 }
 
-static void m_can_echo_tx_event(struct net_device *dev)
+static int m_can_echo_tx_event(struct net_device *dev)
 {
 	u32 txe_count = 0;
 	u32 m_can_txefs;
@@ -984,12 +1024,18 @@ static void m_can_echo_tx_event(struct net_device *dev)
 	/* Get and process all sent elements */
 	for (i = 0; i < txe_count; i++) {
 		u32 txe, timestamp = 0;
+		int err;
 
 		/* retrieve get index */
 		fgi = FIELD_GET(TXEFS_EFGI_MASK, m_can_read(cdev, M_CAN_TXEFS));
 
 		/* get message marker, timestamp */
-		txe = m_can_txe_fifo_read(cdev, fgi, 4);
+		err = m_can_txe_fifo_read(cdev, fgi, 4, &txe);
+		if (err) {
+			netdev_err(dev, "TXE FIFO read returned %d\n", err);
+			return err;
+		}
+
 		msg_mark = FIELD_GET(TX_EVENT_MM_MASK, txe);
 		timestamp = FIELD_GET(TX_EVENT_TXTS_MASK, txe);
 
@@ -1000,6 +1046,8 @@ static void m_can_echo_tx_event(struct net_device *dev)
 		/* update stats */
 		m_can_tx_update_stats(cdev, msg_mark, timestamp);
 	}
+
+	return 0;
 }
 
 static irqreturn_t m_can_isr(int irq, void *dev_id)
@@ -1031,8 +1079,8 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
 		m_can_disable_all_interrupts(cdev);
 		if (!cdev->is_peripheral)
 			napi_schedule(&cdev->napi);
-		else
-			m_can_rx_peripheral(dev);
+		else if (m_can_rx_peripheral(dev) < 0)
+			goto out_fail;
 	}
 
 	if (cdev->version == 30) {
@@ -1050,7 +1098,9 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
 	} else  {
 		if (ir & IR_TEFN) {
 			/* New TX FIFO Element arrived */
-			m_can_echo_tx_event(dev);
+			if (m_can_echo_tx_event(dev) != 0)
+				goto out_fail;
+
 			can_led_event(dev, CAN_LED_EVENT_TX);
 			if (netif_queue_stopped(dev) &&
 			    !m_can_tx_fifo_full(cdev))
@@ -1058,6 +1108,13 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
 		}
 	}
 
+	if (cdev->is_peripheral)
+		can_rx_offload_threaded_irq_finish(&cdev->offload);
+
+	return IRQ_HANDLED;
+
+out_fail:
+	m_can_disable_all_interrupts(cdev);
 	return IRQ_HANDLED;
 }
 
@@ -1302,7 +1359,8 @@ static void m_can_chip_config(struct net_device *dev)
 	m_can_set_bittiming(dev);
 
 	/* enable internal timestamp generation, with a prescalar of 16. The
-	 * prescalar is applied to the nominal bit timing */
+	 * prescalar is applied to the nominal bit timing
+	 */
 	m_can_write(cdev, M_CAN_TSCC, FIELD_PREP(TSCC_TCP_MASK, 0xf));
 
 	m_can_config_endisable(cdev, false);
@@ -1436,32 +1494,20 @@ static int m_can_dev_setup(struct m_can_classdev *cdev)
 	case 30:
 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.0.x */
 		can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
-		cdev->can.bittiming_const = cdev->bit_timing ?
-			cdev->bit_timing : &m_can_bittiming_const_30X;
-
-		cdev->can.data_bittiming_const = cdev->data_timing ?
-			cdev->data_timing :
-			&m_can_data_bittiming_const_30X;
+		cdev->can.bittiming_const = &m_can_bittiming_const_30X;
+		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_30X;
 		break;
 	case 31:
 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.1.x */
 		can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
-		cdev->can.bittiming_const = cdev->bit_timing ?
-			cdev->bit_timing : &m_can_bittiming_const_31X;
-
-		cdev->can.data_bittiming_const = cdev->data_timing ?
-			cdev->data_timing :
-			&m_can_data_bittiming_const_31X;
+		cdev->can.bittiming_const = &m_can_bittiming_const_31X;
+		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_31X;
 		break;
 	case 32:
 	case 33:
 		/* Support both MCAN version v3.2.x and v3.3.0 */
-		cdev->can.bittiming_const = cdev->bit_timing ?
-			cdev->bit_timing : &m_can_bittiming_const_31X;
-
-		cdev->can.data_bittiming_const = cdev->data_timing ?
-			cdev->data_timing :
-			&m_can_data_bittiming_const_31X;
+		cdev->can.bittiming_const = &m_can_bittiming_const_31X;
+		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_31X;
 
 		cdev->can.ctrlmode_supported |=
 			(m_can_niso_supported(cdev) ?
@@ -1518,6 +1564,8 @@ static int m_can_close(struct net_device *dev)
 	close_candev(dev);
 	can_led_event(dev, CAN_LED_EVENT_STOP);
 
+	phy_power_off(cdev->transceiver);
+
 	return 0;
 }
 
@@ -1540,8 +1588,9 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
 	struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;
 	struct net_device *dev = cdev->net;
 	struct sk_buff *skb = cdev->tx_skb;
-	u32 id, cccr, fdflags;
-	int i;
+	struct id_and_dlc fifo_header;
+	u32 cccr, fdflags;
+	int err;
 	int putidx;
 
 	cdev->tx_skb = NULL;
@@ -1549,27 +1598,29 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
 	/* Generate ID field for TX buffer Element */
 	/* Common to all supported M_CAN versions */
 	if (cf->can_id & CAN_EFF_FLAG) {
-		id = cf->can_id & CAN_EFF_MASK;
-		id |= TX_BUF_XTD;
+		fifo_header.id = cf->can_id & CAN_EFF_MASK;
+		fifo_header.id |= TX_BUF_XTD;
 	} else {
-		id = ((cf->can_id & CAN_SFF_MASK) << 18);
+		fifo_header.id = ((cf->can_id & CAN_SFF_MASK) << 18);
 	}
 
 	if (cf->can_id & CAN_RTR_FLAG)
-		id |= TX_BUF_RTR;
+		fifo_header.id |= TX_BUF_RTR;
 
 	if (cdev->version == 30) {
 		netif_stop_queue(dev);
 
-		/* message ram configuration */
-		m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, id);
-		m_can_fifo_write(cdev, 0, M_CAN_FIFO_DLC,
-				 can_fd_len2dlc(cf->len) << 16);
+		fifo_header.dlc = can_fd_len2dlc(cf->len) << 16;
+
+		/* Write the frame ID, DLC, and payload to the FIFO element. */
+		err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, &fifo_header, 2);
+		if (err)
+			goto out_fail;
 
-		for (i = 0; i < cf->len; i += 4)
-			m_can_fifo_write(cdev, 0,
-					 M_CAN_FIFO_DATA(i / 4),
-					 *(u32 *)(cf->data + i));
+		err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_DATA,
+				       cf->data, DIV_ROUND_UP(cf->len, 4));
+		if (err)
+			goto out_fail;
 
 		can_put_echo_skb(skb, dev, 0, 0);
 
@@ -1613,8 +1664,11 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
 		/* get put index for frame */
 		putidx = FIELD_GET(TXFQS_TFQPI_MASK,
 				   m_can_read(cdev, M_CAN_TXFQS));
-		/* Write ID Field to FIFO Element */
-		m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID, id);
+
+		/* Construct DLC Field, with CAN-FD configuration.
+		 * Use the put index of the fifo as the message marker,
+		 * used in the TX interrupt for sending the correct echo frame.
+		 */
 
 		/* get CAN FD configuration of frame */
 		fdflags = 0;
@@ -1624,20 +1678,17 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
 				fdflags |= TX_BUF_BRS;
 		}
 
-		/* Construct DLC Field. Also contains CAN-FD configuration
-		 * use put index of fifo as message marker
-		 * it is used in TX interrupt for
-		 * sending the correct echo frame
-		 */
-		m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DLC,
-				 FIELD_PREP(TX_BUF_MM_MASK, putidx) |
-				 FIELD_PREP(TX_BUF_DLC_MASK,
-					    can_fd_len2dlc(cf->len)) |
-				 fdflags | TX_BUF_EFC);
+		fifo_header.dlc = FIELD_PREP(TX_BUF_MM_MASK, putidx) |
+			FIELD_PREP(TX_BUF_DLC_MASK, can_fd_len2dlc(cf->len)) |
+			fdflags | TX_BUF_EFC;
+		err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID, &fifo_header, 2);
+		if (err)
+			goto out_fail;
 
-		for (i = 0; i < cf->len; i += 4)
-			m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DATA(i / 4),
-					 *(u32 *)(cf->data + i));
+		err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DATA,
+				       cf->data, DIV_ROUND_UP(cf->len, 4));
+		if (err)
+			goto out_fail;
 
 		/* Push loopback echo.
 		 * Will be looped back on TX interrupt based on message marker
@@ -1654,6 +1705,11 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
 	}
 
 	return NETDEV_TX_OK;
+
+out_fail:
+	netdev_err(dev, "FIFO write returned %d\n", err);
+	m_can_disable_all_interrupts(cdev);
+	return NETDEV_TX_BUSY;
 }
 
 static void m_can_tx_work_queue(struct work_struct *ws)
@@ -1703,10 +1759,14 @@ static int m_can_open(struct net_device *dev)
 	struct m_can_classdev *cdev = netdev_priv(dev);
 	int err;
 
-	err = m_can_clk_start(cdev);
+	err = phy_power_on(cdev->transceiver);
 	if (err)
 		return err;
 
+	err = m_can_clk_start(cdev);
+	if (err)
+		goto out_phy_power_off;
+
 	/* open the can device */
 	err = open_candev(dev);
 	if (err) {
@@ -1763,6 +1823,8 @@ out_wq_fail:
 	close_candev(dev);
 exit_disable_clks:
 	m_can_clk_stop(cdev);
+out_phy_power_off:
+	phy_power_off(cdev->transceiver);
 	return err;
 }
 
@@ -1819,9 +1881,10 @@ static void m_can_of_parse_mram(struct m_can_classdev *cdev,
 		cdev->mcfg[MRAM_TXB].off, cdev->mcfg[MRAM_TXB].num);
 }
 
-void m_can_init_ram(struct m_can_classdev *cdev)
+int m_can_init_ram(struct m_can_classdev *cdev)
 {
 	int end, i, start;
+	int err = 0;
 
 	/* initialize the entire Message RAM in use to avoid possible
 	 * ECC/parity checksum errors when reading an uninitialized buffer
@@ -1830,8 +1893,13 @@ void m_can_init_ram(struct m_can_classdev *cdev)
 	end = cdev->mcfg[MRAM_TXB].off +
 		cdev->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE;
 
-	for (i = start; i < end; i += 4)
-		m_can_fifo_write_no_off(cdev, i, 0x0);
+	for (i = start; i < end; i += 4) {
+		err = m_can_fifo_write_no_off(cdev, i, 0x0);
+		if (err)
+			break;
+	}
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(m_can_init_ram);