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tegrakernel/kernel/kernel-4.9/drivers/net/can/xilinx_can.c

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/* Xilinx CAN device driver
*
* Copyright (C) 2012 - 2014 Xilinx, Inc.
* Copyright (C) 2009 PetaLogix. All rights reserved.
* Copyright (C) 2017 Sandvik Mining and Construction Oy
*
* Description:
* This driver is developed for Axi CAN IP and for Zynq CANPS Controller.
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*/
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
#include <linux/can/led.h>
#include <linux/pm_runtime.h>
#define DRIVER_NAME "xilinx_can"
/* CAN registers set */
enum xcan_reg {
XCAN_SRR_OFFSET = 0x00, /* Software reset */
XCAN_MSR_OFFSET = 0x04, /* Mode select */
XCAN_BRPR_OFFSET = 0x08, /* Baud rate prescaler */
XCAN_BTR_OFFSET = 0x0C, /* Bit timing */
XCAN_ECR_OFFSET = 0x10, /* Error counter */
XCAN_ESR_OFFSET = 0x14, /* Error status */
XCAN_SR_OFFSET = 0x18, /* Status */
XCAN_ISR_OFFSET = 0x1C, /* Interrupt status */
XCAN_IER_OFFSET = 0x20, /* Interrupt enable */
XCAN_ICR_OFFSET = 0x24, /* Interrupt clear */
XCAN_TXFIFO_ID_OFFSET = 0x30,/* TX FIFO ID */
XCAN_TXFIFO_DLC_OFFSET = 0x34, /* TX FIFO DLC */
XCAN_TXFIFO_DW1_OFFSET = 0x38, /* TX FIFO Data Word 1 */
XCAN_TXFIFO_DW2_OFFSET = 0x3C, /* TX FIFO Data Word 2 */
XCAN_RXFIFO_ID_OFFSET = 0x50, /* RX FIFO ID */
XCAN_RXFIFO_DLC_OFFSET = 0x54, /* RX FIFO DLC */
XCAN_RXFIFO_DW1_OFFSET = 0x58, /* RX FIFO Data Word 1 */
XCAN_RXFIFO_DW2_OFFSET = 0x5C, /* RX FIFO Data Word 2 */
};
/* CAN register bit masks - XCAN_<REG>_<BIT>_MASK */
#define XCAN_SRR_CEN_MASK 0x00000002 /* CAN enable */
#define XCAN_SRR_RESET_MASK 0x00000001 /* Soft Reset the CAN core */
#define XCAN_MSR_LBACK_MASK 0x00000002 /* Loop back mode select */
#define XCAN_MSR_SLEEP_MASK 0x00000001 /* Sleep mode select */
#define XCAN_BRPR_BRP_MASK 0x000000FF /* Baud rate prescaler */
#define XCAN_BTR_SJW_MASK 0x00000180 /* Synchronous jump width */
#define XCAN_BTR_TS2_MASK 0x00000070 /* Time segment 2 */
#define XCAN_BTR_TS1_MASK 0x0000000F /* Time segment 1 */
#define XCAN_ECR_REC_MASK 0x0000FF00 /* Receive error counter */
#define XCAN_ECR_TEC_MASK 0x000000FF /* Transmit error counter */
#define XCAN_ESR_ACKER_MASK 0x00000010 /* ACK error */
#define XCAN_ESR_BERR_MASK 0x00000008 /* Bit error */
#define XCAN_ESR_STER_MASK 0x00000004 /* Stuff error */
#define XCAN_ESR_FMER_MASK 0x00000002 /* Form error */
#define XCAN_ESR_CRCER_MASK 0x00000001 /* CRC error */
#define XCAN_SR_TXFLL_MASK 0x00000400 /* TX FIFO is full */
#define XCAN_SR_ESTAT_MASK 0x00000180 /* Error status */
#define XCAN_SR_ERRWRN_MASK 0x00000040 /* Error warning */
#define XCAN_SR_NORMAL_MASK 0x00000008 /* Normal mode */
#define XCAN_SR_LBACK_MASK 0x00000002 /* Loop back mode */
#define XCAN_SR_CONFIG_MASK 0x00000001 /* Configuration mode */
#define XCAN_IXR_TXFEMP_MASK 0x00004000 /* TX FIFO Empty */
#define XCAN_IXR_WKUP_MASK 0x00000800 /* Wake up interrupt */
#define XCAN_IXR_SLP_MASK 0x00000400 /* Sleep interrupt */
#define XCAN_IXR_BSOFF_MASK 0x00000200 /* Bus off interrupt */
#define XCAN_IXR_ERROR_MASK 0x00000100 /* Error interrupt */
#define XCAN_IXR_RXNEMP_MASK 0x00000080 /* RX FIFO NotEmpty intr */
#define XCAN_IXR_RXOFLW_MASK 0x00000040 /* RX FIFO Overflow intr */
#define XCAN_IXR_RXOK_MASK 0x00000010 /* Message received intr */
#define XCAN_IXR_TXFLL_MASK 0x00000004 /* Tx FIFO Full intr */
#define XCAN_IXR_TXOK_MASK 0x00000002 /* TX successful intr */
#define XCAN_IXR_ARBLST_MASK 0x00000001 /* Arbitration lost intr */
#define XCAN_IDR_ID1_MASK 0xFFE00000 /* Standard msg identifier */
#define XCAN_IDR_SRR_MASK 0x00100000 /* Substitute remote TXreq */
#define XCAN_IDR_IDE_MASK 0x00080000 /* Identifier extension */
#define XCAN_IDR_ID2_MASK 0x0007FFFE /* Extended message ident */
#define XCAN_IDR_RTR_MASK 0x00000001 /* Remote TX request */
#define XCAN_DLCR_DLC_MASK 0xF0000000 /* Data length code */
#define XCAN_INTR_ALL (XCAN_IXR_TXOK_MASK | XCAN_IXR_BSOFF_MASK |\
XCAN_IXR_WKUP_MASK | XCAN_IXR_SLP_MASK | \
XCAN_IXR_RXNEMP_MASK | XCAN_IXR_ERROR_MASK | \
XCAN_IXR_RXOFLW_MASK | XCAN_IXR_ARBLST_MASK)
/* CAN register bit shift - XCAN_<REG>_<BIT>_SHIFT */
#define XCAN_BTR_SJW_SHIFT 7 /* Synchronous jump width */
#define XCAN_BTR_TS2_SHIFT 4 /* Time segment 2 */
#define XCAN_IDR_ID1_SHIFT 21 /* Standard Messg Identifier */
#define XCAN_IDR_ID2_SHIFT 1 /* Extended Message Identifier */
#define XCAN_DLCR_DLC_SHIFT 28 /* Data length code */
#define XCAN_ESR_REC_SHIFT 8 /* Rx Error Count */
/* CAN frame length constants */
#define XCAN_FRAME_MAX_DATA_LEN 8
#define XCAN_TIMEOUT (1 * HZ)
/**
* struct xcan_priv - This definition define CAN driver instance
* @can: CAN private data structure.
* @tx_lock: Lock for synchronizing TX interrupt handling
* @tx_head: Tx CAN packets ready to send on the queue
* @tx_tail: Tx CAN packets successfully sended on the queue
* @tx_max: Maximum number packets the driver can send
* @napi: NAPI structure
* @read_reg: For reading data from CAN registers
* @write_reg: For writing data to CAN registers
* @dev: Network device data structure
* @reg_base: Ioremapped address to registers
* @irq_flags: For request_irq()
* @bus_clk: Pointer to struct clk
* @can_clk: Pointer to struct clk
*/
struct xcan_priv {
struct can_priv can;
spinlock_t tx_lock;
unsigned int tx_head;
unsigned int tx_tail;
unsigned int tx_max;
struct napi_struct napi;
u32 (*read_reg)(const struct xcan_priv *priv, enum xcan_reg reg);
void (*write_reg)(const struct xcan_priv *priv, enum xcan_reg reg,
u32 val);
struct device *dev;
void __iomem *reg_base;
unsigned long irq_flags;
struct clk *bus_clk;
struct clk *can_clk;
};
/* CAN Bittiming constants as per Xilinx CAN specs */
static const struct can_bittiming_const xcan_bittiming_const = {
.name = DRIVER_NAME,
.tseg1_min = 1,
.tseg1_max = 16,
.tseg2_min = 1,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 256,
.brp_inc = 1,
};
#define XCAN_CAP_WATERMARK 0x0001
struct xcan_devtype_data {
unsigned int caps;
};
/**
* xcan_write_reg_le - Write a value to the device register little endian
* @priv: Driver private data structure
* @reg: Register offset
* @val: Value to write at the Register offset
*
* Write data to the paricular CAN register
*/
static void xcan_write_reg_le(const struct xcan_priv *priv, enum xcan_reg reg,
u32 val)
{
iowrite32(val, priv->reg_base + reg);
}
/**
* xcan_read_reg_le - Read a value from the device register little endian
* @priv: Driver private data structure
* @reg: Register offset
*
* Read data from the particular CAN register
* Return: value read from the CAN register
*/
static u32 xcan_read_reg_le(const struct xcan_priv *priv, enum xcan_reg reg)
{
return ioread32(priv->reg_base + reg);
}
/**
* xcan_write_reg_be - Write a value to the device register big endian
* @priv: Driver private data structure
* @reg: Register offset
* @val: Value to write at the Register offset
*
* Write data to the paricular CAN register
*/
static void xcan_write_reg_be(const struct xcan_priv *priv, enum xcan_reg reg,
u32 val)
{
iowrite32be(val, priv->reg_base + reg);
}
/**
* xcan_read_reg_be - Read a value from the device register big endian
* @priv: Driver private data structure
* @reg: Register offset
*
* Read data from the particular CAN register
* Return: value read from the CAN register
*/
static u32 xcan_read_reg_be(const struct xcan_priv *priv, enum xcan_reg reg)
{
return ioread32be(priv->reg_base + reg);
}
/**
* set_reset_mode - Resets the CAN device mode
* @ndev: Pointer to net_device structure
*
* This is the driver reset mode routine.The driver
* enters into configuration mode.
*
* Return: 0 on success and failure value on error
*/
static int set_reset_mode(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
unsigned long timeout;
priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
timeout = jiffies + XCAN_TIMEOUT;
while (!(priv->read_reg(priv, XCAN_SR_OFFSET) & XCAN_SR_CONFIG_MASK)) {
if (time_after(jiffies, timeout)) {
netdev_warn(ndev, "timed out for config mode\n");
return -ETIMEDOUT;
}
usleep_range(500, 10000);
}
/* reset clears FIFOs */
priv->tx_head = 0;
priv->tx_tail = 0;
return 0;
}
/**
* xcan_set_bittiming - CAN set bit timing routine
* @ndev: Pointer to net_device structure
*
* This is the driver set bittiming routine.
* Return: 0 on success and failure value on error
*/
static int xcan_set_bittiming(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
struct can_bittiming *bt = &priv->can.bittiming;
u32 btr0, btr1;
u32 is_config_mode;
/* Check whether Xilinx CAN is in configuration mode.
* It cannot set bit timing if Xilinx CAN is not in configuration mode.
*/
is_config_mode = priv->read_reg(priv, XCAN_SR_OFFSET) &
XCAN_SR_CONFIG_MASK;
if (!is_config_mode) {
netdev_alert(ndev,
"BUG! Cannot set bittiming - CAN is not in config mode\n");
return -EPERM;
}
/* Setting Baud Rate prescalar value in BRPR Register */
btr0 = (bt->brp - 1);
/* Setting Time Segment 1 in BTR Register */
btr1 = (bt->prop_seg + bt->phase_seg1 - 1);
/* Setting Time Segment 2 in BTR Register */
btr1 |= (bt->phase_seg2 - 1) << XCAN_BTR_TS2_SHIFT;
/* Setting Synchronous jump width in BTR Register */
btr1 |= (bt->sjw - 1) << XCAN_BTR_SJW_SHIFT;
priv->write_reg(priv, XCAN_BRPR_OFFSET, btr0);
priv->write_reg(priv, XCAN_BTR_OFFSET, btr1);
netdev_dbg(ndev, "BRPR=0x%08x, BTR=0x%08x\n",
priv->read_reg(priv, XCAN_BRPR_OFFSET),
priv->read_reg(priv, XCAN_BTR_OFFSET));
return 0;
}
/**
* xcan_chip_start - This the drivers start routine
* @ndev: Pointer to net_device structure
*
* This is the drivers start routine.
* Based on the State of the CAN device it puts
* the CAN device into a proper mode.
*
* Return: 0 on success and failure value on error
*/
static int xcan_chip_start(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
u32 reg_msr, reg_sr_mask;
int err;
unsigned long timeout;
/* Check if it is in reset mode */
err = set_reset_mode(ndev);
if (err < 0)
return err;
err = xcan_set_bittiming(ndev);
if (err < 0)
return err;
/* Enable interrupts */
priv->write_reg(priv, XCAN_IER_OFFSET, XCAN_INTR_ALL);
/* Check whether it is loopback mode or normal mode */
if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
reg_msr = XCAN_MSR_LBACK_MASK;
reg_sr_mask = XCAN_SR_LBACK_MASK;
} else {
reg_msr = 0x0;
reg_sr_mask = XCAN_SR_NORMAL_MASK;
}
priv->write_reg(priv, XCAN_MSR_OFFSET, reg_msr);
priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_CEN_MASK);
timeout = jiffies + XCAN_TIMEOUT;
while (!(priv->read_reg(priv, XCAN_SR_OFFSET) & reg_sr_mask)) {
if (time_after(jiffies, timeout)) {
netdev_warn(ndev,
"timed out for correct mode\n");
return -ETIMEDOUT;
}
}
netdev_dbg(ndev, "status:#x%08x\n",
priv->read_reg(priv, XCAN_SR_OFFSET));
priv->can.state = CAN_STATE_ERROR_ACTIVE;
return 0;
}
/**
* xcan_do_set_mode - This sets the mode of the driver
* @ndev: Pointer to net_device structure
* @mode: Tells the mode of the driver
*
* This check the drivers state and calls the
* the corresponding modes to set.
*
* Return: 0 on success and failure value on error
*/
static int xcan_do_set_mode(struct net_device *ndev, enum can_mode mode)
{
int ret;
switch (mode) {
case CAN_MODE_START:
ret = xcan_chip_start(ndev);
if (ret < 0) {
netdev_err(ndev, "xcan_chip_start failed!\n");
return ret;
}
netif_wake_queue(ndev);
break;
default:
ret = -EOPNOTSUPP;
break;
}
return ret;
}
/**
* xcan_start_xmit - Starts the transmission
* @skb: sk_buff pointer that contains data to be Txed
* @ndev: Pointer to net_device structure
*
* This function is invoked from upper layers to initiate transmission. This
* function uses the next available free txbuff and populates their fields to
* start the transmission.
*
* Return: 0 on success and failure value on error
*/
static int xcan_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
struct net_device_stats *stats = &ndev->stats;
struct can_frame *cf = (struct can_frame *)skb->data;
u32 id, dlc, data[2] = {0, 0};
unsigned long flags;
if (can_dropped_invalid_skb(ndev, skb))
return NETDEV_TX_OK;
/* Check if the TX buffer is full */
if (unlikely(priv->read_reg(priv, XCAN_SR_OFFSET) &
XCAN_SR_TXFLL_MASK)) {
netif_stop_queue(ndev);
netdev_err(ndev, "BUG!, TX FIFO full when queue awake!\n");
return NETDEV_TX_BUSY;
}
/* Watch carefully on the bit sequence */
if (cf->can_id & CAN_EFF_FLAG) {
/* Extended CAN ID format */
id = ((cf->can_id & CAN_EFF_MASK) << XCAN_IDR_ID2_SHIFT) &
XCAN_IDR_ID2_MASK;
id |= (((cf->can_id & CAN_EFF_MASK) >>
(CAN_EFF_ID_BITS-CAN_SFF_ID_BITS)) <<
XCAN_IDR_ID1_SHIFT) & XCAN_IDR_ID1_MASK;
/* The substibute remote TX request bit should be "1"
* for extended frames as in the Xilinx CAN datasheet
*/
id |= XCAN_IDR_IDE_MASK | XCAN_IDR_SRR_MASK;
if (cf->can_id & CAN_RTR_FLAG)
/* Extended frames remote TX request */
id |= XCAN_IDR_RTR_MASK;
} else {
/* Standard CAN ID format */
id = ((cf->can_id & CAN_SFF_MASK) << XCAN_IDR_ID1_SHIFT) &
XCAN_IDR_ID1_MASK;
if (cf->can_id & CAN_RTR_FLAG)
/* Standard frames remote TX request */
id |= XCAN_IDR_SRR_MASK;
}
dlc = cf->can_dlc << XCAN_DLCR_DLC_SHIFT;
if (cf->can_dlc > 0)
data[0] = be32_to_cpup((__be32 *)(cf->data + 0));
if (cf->can_dlc > 4)
data[1] = be32_to_cpup((__be32 *)(cf->data + 4));
can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max);
spin_lock_irqsave(&priv->tx_lock, flags);
priv->tx_head++;
/* Write the Frame to Xilinx CAN TX FIFO */
priv->write_reg(priv, XCAN_TXFIFO_ID_OFFSET, id);
/* If the CAN frame is RTR frame this write triggers tranmission */
priv->write_reg(priv, XCAN_TXFIFO_DLC_OFFSET, dlc);
if (!(cf->can_id & CAN_RTR_FLAG)) {
priv->write_reg(priv, XCAN_TXFIFO_DW1_OFFSET, data[0]);
/* If the CAN frame is Standard/Extended frame this
* write triggers tranmission
*/
priv->write_reg(priv, XCAN_TXFIFO_DW2_OFFSET, data[1]);
stats->tx_bytes += cf->can_dlc;
}
/* Clear TX-FIFO-empty interrupt for xcan_tx_interrupt() */
if (priv->tx_max > 1)
priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXFEMP_MASK);
/* Check if the TX buffer is full */
if ((priv->tx_head - priv->tx_tail) == priv->tx_max)
netif_stop_queue(ndev);
spin_unlock_irqrestore(&priv->tx_lock, flags);
return NETDEV_TX_OK;
}
/**
* xcan_rx - Is called from CAN isr to complete the received
* frame processing
* @ndev: Pointer to net_device structure
*
* This function is invoked from the CAN isr(poll) to process the Rx frames. It
* does minimal processing and invokes "netif_receive_skb" to complete further
* processing.
* Return: 1 on success and 0 on failure.
*/
static int xcan_rx(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
struct net_device_stats *stats = &ndev->stats;
struct can_frame *cf;
struct sk_buff *skb;
u32 id_xcan, dlc, data[2] = {0, 0};
skb = alloc_can_skb(ndev, &cf);
if (unlikely(!skb)) {
stats->rx_dropped++;
return 0;
}
/* Read a frame from Xilinx zynq CANPS */
id_xcan = priv->read_reg(priv, XCAN_RXFIFO_ID_OFFSET);
dlc = priv->read_reg(priv, XCAN_RXFIFO_DLC_OFFSET) >>
XCAN_DLCR_DLC_SHIFT;
/* Change Xilinx CAN data length format to socketCAN data format */
cf->can_dlc = get_can_dlc(dlc);
/* Change Xilinx CAN ID format to socketCAN ID format */
if (id_xcan & XCAN_IDR_IDE_MASK) {
/* The received frame is an Extended format frame */
cf->can_id = (id_xcan & XCAN_IDR_ID1_MASK) >> 3;
cf->can_id |= (id_xcan & XCAN_IDR_ID2_MASK) >>
XCAN_IDR_ID2_SHIFT;
cf->can_id |= CAN_EFF_FLAG;
if (id_xcan & XCAN_IDR_RTR_MASK)
cf->can_id |= CAN_RTR_FLAG;
} else {
/* The received frame is a standard format frame */
cf->can_id = (id_xcan & XCAN_IDR_ID1_MASK) >>
XCAN_IDR_ID1_SHIFT;
if (id_xcan & XCAN_IDR_SRR_MASK)
cf->can_id |= CAN_RTR_FLAG;
}
/* DW1/DW2 must always be read to remove message from RXFIFO */
data[0] = priv->read_reg(priv, XCAN_RXFIFO_DW1_OFFSET);
data[1] = priv->read_reg(priv, XCAN_RXFIFO_DW2_OFFSET);
if (!(cf->can_id & CAN_RTR_FLAG)) {
/* Change Xilinx CAN data format to socketCAN data format */
if (cf->can_dlc > 0)
*(__be32 *)(cf->data) = cpu_to_be32(data[0]);
if (cf->can_dlc > 4)
*(__be32 *)(cf->data + 4) = cpu_to_be32(data[1]);
}
stats->rx_bytes += cf->can_dlc;
stats->rx_packets++;
netif_receive_skb(skb);
return 1;
}
/**
* xcan_current_error_state - Get current error state from HW
* @ndev: Pointer to net_device structure
*
* Checks the current CAN error state from the HW. Note that this
* only checks for ERROR_PASSIVE and ERROR_WARNING.
*
* Return:
* ERROR_PASSIVE or ERROR_WARNING if either is active, ERROR_ACTIVE
* otherwise.
*/
static enum can_state xcan_current_error_state(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
u32 status = priv->read_reg(priv, XCAN_SR_OFFSET);
if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK)
return CAN_STATE_ERROR_PASSIVE;
else if (status & XCAN_SR_ERRWRN_MASK)
return CAN_STATE_ERROR_WARNING;
else
return CAN_STATE_ERROR_ACTIVE;
}
/**
* xcan_set_error_state - Set new CAN error state
* @ndev: Pointer to net_device structure
* @new_state: The new CAN state to be set
* @cf: Error frame to be populated or NULL
*
* Set new CAN error state for the device, updating statistics and
* populating the error frame if given.
*/
static void xcan_set_error_state(struct net_device *ndev,
enum can_state new_state,
struct can_frame *cf)
{
struct xcan_priv *priv = netdev_priv(ndev);
u32 ecr = priv->read_reg(priv, XCAN_ECR_OFFSET);
u32 txerr = ecr & XCAN_ECR_TEC_MASK;
u32 rxerr = (ecr & XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT;
priv->can.state = new_state;
if (cf) {
cf->can_id |= CAN_ERR_CRTL;
cf->data[6] = txerr;
cf->data[7] = rxerr;
}
switch (new_state) {
case CAN_STATE_ERROR_PASSIVE:
priv->can.can_stats.error_passive++;
if (cf)
cf->data[1] = (rxerr > 127) ?
CAN_ERR_CRTL_RX_PASSIVE :
CAN_ERR_CRTL_TX_PASSIVE;
break;
case CAN_STATE_ERROR_WARNING:
priv->can.can_stats.error_warning++;
if (cf)
cf->data[1] |= (txerr > rxerr) ?
CAN_ERR_CRTL_TX_WARNING :
CAN_ERR_CRTL_RX_WARNING;
break;
case CAN_STATE_ERROR_ACTIVE:
if (cf)
cf->data[1] |= CAN_ERR_CRTL_ACTIVE;
break;
default:
/* non-ERROR states are handled elsewhere */
WARN_ON(1);
break;
}
}
/**
* xcan_update_error_state_after_rxtx - Update CAN error state after RX/TX
* @ndev: Pointer to net_device structure
*
* If the device is in a ERROR-WARNING or ERROR-PASSIVE state, check if
* the performed RX/TX has caused it to drop to a lesser state and set
* the interface state accordingly.
*/
static void xcan_update_error_state_after_rxtx(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
enum can_state old_state = priv->can.state;
enum can_state new_state;
/* changing error state due to successful frame RX/TX can only
* occur from these states
*/
if (old_state != CAN_STATE_ERROR_WARNING &&
old_state != CAN_STATE_ERROR_PASSIVE)
return;
new_state = xcan_current_error_state(ndev);
if (new_state != old_state) {
struct sk_buff *skb;
struct can_frame *cf;
skb = alloc_can_err_skb(ndev, &cf);
xcan_set_error_state(ndev, new_state, skb ? cf : NULL);
if (skb) {
struct net_device_stats *stats = &ndev->stats;
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
netif_rx(skb);
}
}
}
/**
* xcan_err_interrupt - error frame Isr
* @ndev: net_device pointer
* @isr: interrupt status register value
*
* This is the CAN error interrupt and it will
* check the the type of error and forward the error
* frame to upper layers.
*/
static void xcan_err_interrupt(struct net_device *ndev, u32 isr)
{
struct xcan_priv *priv = netdev_priv(ndev);
struct net_device_stats *stats = &ndev->stats;
struct can_frame *cf;
struct sk_buff *skb;
u32 err_status;
skb = alloc_can_err_skb(ndev, &cf);
err_status = priv->read_reg(priv, XCAN_ESR_OFFSET);
priv->write_reg(priv, XCAN_ESR_OFFSET, err_status);
if (isr & XCAN_IXR_BSOFF_MASK) {
priv->can.state = CAN_STATE_BUS_OFF;
priv->can.can_stats.bus_off++;
/* Leave device in Config Mode in bus-off state */
priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
can_bus_off(ndev);
if (skb)
cf->can_id |= CAN_ERR_BUSOFF;
} else {
enum can_state new_state = xcan_current_error_state(ndev);
xcan_set_error_state(ndev, new_state, skb ? cf : NULL);
}
/* Check for Arbitration lost interrupt */
if (isr & XCAN_IXR_ARBLST_MASK) {
priv->can.can_stats.arbitration_lost++;
if (skb) {
cf->can_id |= CAN_ERR_LOSTARB;
cf->data[0] = CAN_ERR_LOSTARB_UNSPEC;
}
}
/* Check for RX FIFO Overflow interrupt */
if (isr & XCAN_IXR_RXOFLW_MASK) {
stats->rx_over_errors++;
stats->rx_errors++;
if (skb) {
cf->can_id |= CAN_ERR_CRTL;
cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
}
}
/* Check for error interrupt */
if (isr & XCAN_IXR_ERROR_MASK) {
if (skb)
cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
/* Check for Ack error interrupt */
if (err_status & XCAN_ESR_ACKER_MASK) {
stats->tx_errors++;
if (skb) {
cf->can_id |= CAN_ERR_ACK;
cf->data[3] = CAN_ERR_PROT_LOC_ACK;
}
}
/* Check for Bit error interrupt */
if (err_status & XCAN_ESR_BERR_MASK) {
stats->tx_errors++;
if (skb) {
cf->can_id |= CAN_ERR_PROT;
cf->data[2] = CAN_ERR_PROT_BIT;
}
}
/* Check for Stuff error interrupt */
if (err_status & XCAN_ESR_STER_MASK) {
stats->rx_errors++;
if (skb) {
cf->can_id |= CAN_ERR_PROT;
cf->data[2] = CAN_ERR_PROT_STUFF;
}
}
/* Check for Form error interrupt */
if (err_status & XCAN_ESR_FMER_MASK) {
stats->rx_errors++;
if (skb) {
cf->can_id |= CAN_ERR_PROT;
cf->data[2] = CAN_ERR_PROT_FORM;
}
}
/* Check for CRC error interrupt */
if (err_status & XCAN_ESR_CRCER_MASK) {
stats->rx_errors++;
if (skb) {
cf->can_id |= CAN_ERR_PROT;
cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
}
}
priv->can.can_stats.bus_error++;
}
if (skb) {
stats->rx_packets++;
stats->rx_bytes += cf->can_dlc;
netif_rx(skb);
}
netdev_dbg(ndev, "%s: error status register:0x%x\n",
__func__, priv->read_reg(priv, XCAN_ESR_OFFSET));
}
/**
* xcan_state_interrupt - It will check the state of the CAN device
* @ndev: net_device pointer
* @isr: interrupt status register value
*
* This will checks the state of the CAN device
* and puts the device into appropriate state.
*/
static void xcan_state_interrupt(struct net_device *ndev, u32 isr)
{
struct xcan_priv *priv = netdev_priv(ndev);
/* Check for Sleep interrupt if set put CAN device in sleep state */
if (isr & XCAN_IXR_SLP_MASK)
priv->can.state = CAN_STATE_SLEEPING;
/* Check for Wake up interrupt if set put CAN device in Active state */
if (isr & XCAN_IXR_WKUP_MASK)
priv->can.state = CAN_STATE_ERROR_ACTIVE;
}
/**
* xcan_rx_poll - Poll routine for rx packets (NAPI)
* @napi: napi structure pointer
* @quota: Max number of rx packets to be processed.
*
* This is the poll routine for rx part.
* It will process the packets maximux quota value.
*
* Return: number of packets received
*/
static int xcan_rx_poll(struct napi_struct *napi, int quota)
{
struct net_device *ndev = napi->dev;
struct xcan_priv *priv = netdev_priv(ndev);
u32 isr, ier;
int work_done = 0;
isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
while ((isr & XCAN_IXR_RXNEMP_MASK) && (work_done < quota)) {
work_done += xcan_rx(ndev);
priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_RXNEMP_MASK);
isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
}
if (work_done) {
can_led_event(ndev, CAN_LED_EVENT_RX);
xcan_update_error_state_after_rxtx(ndev);
}
if (work_done < quota) {
napi_complete(napi);
ier = priv->read_reg(priv, XCAN_IER_OFFSET);
ier |= XCAN_IXR_RXNEMP_MASK;
priv->write_reg(priv, XCAN_IER_OFFSET, ier);
}
return work_done;
}
/**
* xcan_tx_interrupt - Tx Done Isr
* @ndev: net_device pointer
* @isr: Interrupt status register value
*/
static void xcan_tx_interrupt(struct net_device *ndev, u32 isr)
{
struct xcan_priv *priv = netdev_priv(ndev);
struct net_device_stats *stats = &ndev->stats;
unsigned int frames_in_fifo;
int frames_sent = 1; /* TXOK => at least 1 frame was sent */
unsigned long flags;
int retries = 0;
/* Synchronize with xmit as we need to know the exact number
* of frames in the FIFO to stay in sync due to the TXFEMP
* handling.
* This also prevents a race between netif_wake_queue() and
* netif_stop_queue().
*/
spin_lock_irqsave(&priv->tx_lock, flags);
frames_in_fifo = priv->tx_head - priv->tx_tail;
if (WARN_ON_ONCE(frames_in_fifo == 0)) {
/* clear TXOK anyway to avoid getting back here */
priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK);
spin_unlock_irqrestore(&priv->tx_lock, flags);
return;
}
/* Check if 2 frames were sent (TXOK only means that at least 1
* frame was sent).
*/
if (frames_in_fifo > 1) {
WARN_ON(frames_in_fifo > priv->tx_max);
/* Synchronize TXOK and isr so that after the loop:
* (1) isr variable is up-to-date at least up to TXOK clear
* time. This avoids us clearing a TXOK of a second frame
* but not noticing that the FIFO is now empty and thus
* marking only a single frame as sent.
* (2) No TXOK is left. Having one could mean leaving a
* stray TXOK as we might process the associated frame
* via TXFEMP handling as we read TXFEMP *after* TXOK
* clear to satisfy (1).
*/
while ((isr & XCAN_IXR_TXOK_MASK) && !WARN_ON(++retries == 100)) {
priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK);
isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
}
if (isr & XCAN_IXR_TXFEMP_MASK) {
/* nothing in FIFO anymore */
frames_sent = frames_in_fifo;
}
} else {
/* single frame in fifo, just clear TXOK */
priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK);
}
while (frames_sent--) {
can_get_echo_skb(ndev, priv->tx_tail %
priv->tx_max);
priv->tx_tail++;
stats->tx_packets++;
}
netif_wake_queue(ndev);
spin_unlock_irqrestore(&priv->tx_lock, flags);
can_led_event(ndev, CAN_LED_EVENT_TX);
xcan_update_error_state_after_rxtx(ndev);
}
/**
* xcan_interrupt - CAN Isr
* @irq: irq number
* @dev_id: device id poniter
*
* This is the xilinx CAN Isr. It checks for the type of interrupt
* and invokes the corresponding ISR.
*
* Return:
* IRQ_NONE - If CAN device is in sleep mode, IRQ_HANDLED otherwise
*/
static irqreturn_t xcan_interrupt(int irq, void *dev_id)
{
struct net_device *ndev = (struct net_device *)dev_id;
struct xcan_priv *priv = netdev_priv(ndev);
u32 isr, ier;
u32 isr_errors;
/* Get the interrupt status from Xilinx CAN */
isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
if (!isr)
return IRQ_NONE;
/* Check for the type of interrupt and Processing it */
if (isr & (XCAN_IXR_SLP_MASK | XCAN_IXR_WKUP_MASK)) {
priv->write_reg(priv, XCAN_ICR_OFFSET, (XCAN_IXR_SLP_MASK |
XCAN_IXR_WKUP_MASK));
xcan_state_interrupt(ndev, isr);
}
/* Check for Tx interrupt and Processing it */
if (isr & XCAN_IXR_TXOK_MASK)
xcan_tx_interrupt(ndev, isr);
/* Check for the type of error interrupt and Processing it */
isr_errors = isr & (XCAN_IXR_ERROR_MASK | XCAN_IXR_RXOFLW_MASK |
XCAN_IXR_BSOFF_MASK | XCAN_IXR_ARBLST_MASK);
if (isr_errors) {
priv->write_reg(priv, XCAN_ICR_OFFSET, isr_errors);
xcan_err_interrupt(ndev, isr);
}
/* Check for the type of receive interrupt and Processing it */
if (isr & XCAN_IXR_RXNEMP_MASK) {
ier = priv->read_reg(priv, XCAN_IER_OFFSET);
ier &= ~XCAN_IXR_RXNEMP_MASK;
priv->write_reg(priv, XCAN_IER_OFFSET, ier);
napi_schedule(&priv->napi);
}
return IRQ_HANDLED;
}
/**
* xcan_chip_stop - Driver stop routine
* @ndev: Pointer to net_device structure
*
* This is the drivers stop routine. It will disable the
* interrupts and put the device into configuration mode.
*/
static void xcan_chip_stop(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
/* Disable interrupts and leave the can in configuration mode */
set_reset_mode(ndev);
priv->can.state = CAN_STATE_STOPPED;
}
/**
* xcan_open - Driver open routine
* @ndev: Pointer to net_device structure
*
* This is the driver open routine.
* Return: 0 on success and failure value on error
*/
static int xcan_open(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
int ret;
ret = pm_runtime_get_sync(priv->dev);
if (ret < 0) {
netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
__func__, ret);
return ret;
}
ret = request_irq(ndev->irq, xcan_interrupt, priv->irq_flags,
ndev->name, ndev);
if (ret < 0) {
netdev_err(ndev, "irq allocation for CAN failed\n");
goto err;
}
/* Set chip into reset mode */
ret = set_reset_mode(ndev);
if (ret < 0) {
netdev_err(ndev, "mode resetting failed!\n");
goto err_irq;
}
/* Common open */
ret = open_candev(ndev);
if (ret)
goto err_irq;
ret = xcan_chip_start(ndev);
if (ret < 0) {
netdev_err(ndev, "xcan_chip_start failed!\n");
goto err_candev;
}
can_led_event(ndev, CAN_LED_EVENT_OPEN);
napi_enable(&priv->napi);
netif_start_queue(ndev);
return 0;
err_candev:
close_candev(ndev);
err_irq:
free_irq(ndev->irq, ndev);
err:
pm_runtime_put(priv->dev);
return ret;
}
/**
* xcan_close - Driver close routine
* @ndev: Pointer to net_device structure
*
* Return: 0 always
*/
static int xcan_close(struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
netif_stop_queue(ndev);
napi_disable(&priv->napi);
xcan_chip_stop(ndev);
free_irq(ndev->irq, ndev);
close_candev(ndev);
can_led_event(ndev, CAN_LED_EVENT_STOP);
pm_runtime_put(priv->dev);
return 0;
}
/**
* xcan_get_berr_counter - error counter routine
* @ndev: Pointer to net_device structure
* @bec: Pointer to can_berr_counter structure
*
* This is the driver error counter routine.
* Return: 0 on success and failure value on error
*/
static int xcan_get_berr_counter(const struct net_device *ndev,
struct can_berr_counter *bec)
{
struct xcan_priv *priv = netdev_priv(ndev);
int ret;
ret = pm_runtime_get_sync(priv->dev);
if (ret < 0) {
netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
__func__, ret);
return ret;
}
bec->txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) & XCAN_ECR_TEC_MASK;
bec->rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) &
XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT);
pm_runtime_put(priv->dev);
return 0;
}
static const struct net_device_ops xcan_netdev_ops = {
.ndo_open = xcan_open,
.ndo_stop = xcan_close,
.ndo_start_xmit = xcan_start_xmit,
.ndo_change_mtu = can_change_mtu,
};
/**
* xcan_suspend - Suspend method for the driver
* @dev: Address of the device structure
*
* Put the driver into low power mode.
* Return: 0 on success and failure value on error
*/
static int __maybe_unused xcan_suspend(struct device *dev)
{
struct net_device *ndev = dev_get_drvdata(dev);
if (netif_running(ndev)) {
netif_stop_queue(ndev);
netif_device_detach(ndev);
xcan_chip_stop(ndev);
}
return pm_runtime_force_suspend(dev);
}
/**
* xcan_resume - Resume from suspend
* @dev: Address of the device structure
*
* Resume operation after suspend.
* Return: 0 on success and failure value on error
*/
static int __maybe_unused xcan_resume(struct device *dev)
{
struct net_device *ndev = dev_get_drvdata(dev);
int ret;
ret = pm_runtime_force_resume(dev);
if (ret) {
dev_err(dev, "pm_runtime_force_resume failed on resume\n");
return ret;
}
if (netif_running(ndev)) {
ret = xcan_chip_start(ndev);
if (ret) {
dev_err(dev, "xcan_chip_start failed on resume\n");
return ret;
}
netif_device_attach(ndev);
netif_start_queue(ndev);
}
return 0;
}
/**
* xcan_runtime_suspend - Runtime suspend method for the driver
* @dev: Address of the device structure
*
* Put the driver into low power mode.
* Return: 0 always
*/
static int __maybe_unused xcan_runtime_suspend(struct device *dev)
{
struct net_device *ndev = dev_get_drvdata(dev);
struct xcan_priv *priv = netdev_priv(ndev);
clk_disable_unprepare(priv->bus_clk);
clk_disable_unprepare(priv->can_clk);
return 0;
}
/**
* xcan_runtime_resume - Runtime resume from suspend
* @dev: Address of the device structure
*
* Resume operation after suspend.
* Return: 0 on success and failure value on error
*/
static int __maybe_unused xcan_runtime_resume(struct device *dev)
{
struct net_device *ndev = dev_get_drvdata(dev);
struct xcan_priv *priv = netdev_priv(ndev);
int ret;
ret = clk_prepare_enable(priv->bus_clk);
if (ret) {
dev_err(dev, "Cannot enable clock.\n");
return ret;
}
ret = clk_prepare_enable(priv->can_clk);
if (ret) {
dev_err(dev, "Cannot enable clock.\n");
clk_disable_unprepare(priv->bus_clk);
return ret;
}
return 0;
}
static const struct dev_pm_ops xcan_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(xcan_suspend, xcan_resume)
SET_RUNTIME_PM_OPS(xcan_runtime_suspend, xcan_runtime_resume, NULL)
};
static const struct xcan_devtype_data xcan_zynq_data = {
.caps = XCAN_CAP_WATERMARK,
};
/* Match table for OF platform binding */
static const struct of_device_id xcan_of_match[] = {
{ .compatible = "xlnx,zynq-can-1.0", .data = &xcan_zynq_data },
{ .compatible = "xlnx,axi-can-1.00.a", },
{ /* end of list */ },
};
MODULE_DEVICE_TABLE(of, xcan_of_match);
/**
* xcan_probe - Platform registration call
* @pdev: Handle to the platform device structure
*
* This function does all the memory allocation and registration for the CAN
* device.
*
* Return: 0 on success and failure value on error
*/
static int xcan_probe(struct platform_device *pdev)
{
struct resource *res; /* IO mem resources */
struct net_device *ndev;
struct xcan_priv *priv;
const struct of_device_id *of_id;
int caps = 0;
void __iomem *addr;
int ret, rx_max, tx_max, tx_fifo_depth;
/* Get the virtual base address for the device */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
addr = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(addr)) {
ret = PTR_ERR(addr);
goto err;
}
ret = of_property_read_u32(pdev->dev.of_node, "tx-fifo-depth",
&tx_fifo_depth);
if (ret < 0)
goto err;
ret = of_property_read_u32(pdev->dev.of_node, "rx-fifo-depth", &rx_max);
if (ret < 0)
goto err;
of_id = of_match_device(xcan_of_match, &pdev->dev);
if (of_id) {
const struct xcan_devtype_data *devtype_data = of_id->data;
if (devtype_data)
caps = devtype_data->caps;
}
/* There is no way to directly figure out how many frames have been
* sent when the TXOK interrupt is processed. If watermark programming
* is supported, we can have 2 frames in the FIFO and use TXFEMP
* to determine if 1 or 2 frames have been sent.
* Theoretically we should be able to use TXFWMEMP to determine up
* to 3 frames, but it seems that after putting a second frame in the
* FIFO, with watermark at 2 frames, it can happen that TXFWMEMP (less
* than 2 frames in FIFO) is set anyway with no TXOK (a frame was
* sent), which is not a sensible state - possibly TXFWMEMP is not
* completely synchronized with the rest of the bits?
*/
if (caps & XCAN_CAP_WATERMARK)
tx_max = min(tx_fifo_depth, 2);
else
tx_max = 1;
/* Create a CAN device instance */
ndev = alloc_candev(sizeof(struct xcan_priv), tx_max);
if (!ndev)
return -ENOMEM;
priv = netdev_priv(ndev);
priv->dev = &pdev->dev;
priv->can.bittiming_const = &xcan_bittiming_const;
priv->can.do_set_mode = xcan_do_set_mode;
priv->can.do_get_berr_counter = xcan_get_berr_counter;
priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
CAN_CTRLMODE_BERR_REPORTING;
priv->reg_base = addr;
priv->tx_max = tx_max;
spin_lock_init(&priv->tx_lock);
/* Get IRQ for the device */
ndev->irq = platform_get_irq(pdev, 0);
ndev->flags |= IFF_ECHO; /* We support local echo */
platform_set_drvdata(pdev, ndev);
SET_NETDEV_DEV(ndev, &pdev->dev);
ndev->netdev_ops = &xcan_netdev_ops;
/* Getting the CAN can_clk info */
priv->can_clk = devm_clk_get(&pdev->dev, "can_clk");
if (IS_ERR(priv->can_clk)) {
dev_err(&pdev->dev, "Device clock not found.\n");
ret = PTR_ERR(priv->can_clk);
goto err_free;
}
/* Check for type of CAN device */
if (of_device_is_compatible(pdev->dev.of_node,
"xlnx,zynq-can-1.0")) {
priv->bus_clk = devm_clk_get(&pdev->dev, "pclk");
if (IS_ERR(priv->bus_clk)) {
dev_err(&pdev->dev, "bus clock not found\n");
ret = PTR_ERR(priv->bus_clk);
goto err_free;
}
} else {
priv->bus_clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
if (IS_ERR(priv->bus_clk)) {
dev_err(&pdev->dev, "bus clock not found\n");
ret = PTR_ERR(priv->bus_clk);
goto err_free;
}
}
priv->write_reg = xcan_write_reg_le;
priv->read_reg = xcan_read_reg_le;
pm_runtime_enable(&pdev->dev);
ret = pm_runtime_get_sync(&pdev->dev);
if (ret < 0) {
netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
__func__, ret);
goto err_pmdisable;
}
if (priv->read_reg(priv, XCAN_SR_OFFSET) != XCAN_SR_CONFIG_MASK) {
priv->write_reg = xcan_write_reg_be;
priv->read_reg = xcan_read_reg_be;
}
priv->can.clock.freq = clk_get_rate(priv->can_clk);
netif_napi_add(ndev, &priv->napi, xcan_rx_poll, rx_max);
ret = register_candev(ndev);
if (ret) {
dev_err(&pdev->dev, "fail to register failed (err=%d)\n", ret);
goto err_disableclks;
}
devm_can_led_init(ndev);
pm_runtime_put(&pdev->dev);
netdev_dbg(ndev, "reg_base=0x%p irq=%d clock=%d, tx fifo depth: actual %d, using %d\n",
priv->reg_base, ndev->irq, priv->can.clock.freq,
tx_fifo_depth, priv->tx_max);
return 0;
err_disableclks:
pm_runtime_put(priv->dev);
err_pmdisable:
pm_runtime_disable(&pdev->dev);
err_free:
free_candev(ndev);
err:
return ret;
}
/**
* xcan_remove - Unregister the device after releasing the resources
* @pdev: Handle to the platform device structure
*
* This function frees all the resources allocated to the device.
* Return: 0 always
*/
static int xcan_remove(struct platform_device *pdev)
{
struct net_device *ndev = platform_get_drvdata(pdev);
struct xcan_priv *priv = netdev_priv(ndev);
unregister_candev(ndev);
pm_runtime_disable(&pdev->dev);
netif_napi_del(&priv->napi);
free_candev(ndev);
return 0;
}
static struct platform_driver xcan_driver = {
.probe = xcan_probe,
.remove = xcan_remove,
.driver = {
.name = DRIVER_NAME,
.pm = &xcan_dev_pm_ops,
.of_match_table = xcan_of_match,
},
};
module_platform_driver(xcan_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Xilinx Inc");
MODULE_DESCRIPTION("Xilinx CAN interface");
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