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1598efe57b
linux/drivers/net/can/xilinx_can.c
Anssi Hannula 1598efe57b can: xilinx_can: refactor code in preparation for CAN FD support 
Xilinx CAN FD cores are different enough from the previous Zynq and AXI
CAN cores that some refactoring of the driver is needed.

This commit contains most of the required refactoring to existing code
and should not alter behavior on existing supported HW.

The changes are:

- Reading and writing to frame registers is parametrized to allow
  reading/writing a different frame in the future.

- Slightly misleading (as it did not specify *all* the interrupts
  supported by the HW) XCAN_INTR_ALL is replaced with specifying the
  interrupts inline in interrupt enabling code.

- xcan_devtype_data.caps is renamed to xcan_devtype_data.flags to allow
  for flags that define alternative functionality (e.g. mailboxes vs.
  FIFO) instead of purely additive capabilities.

- can_bittiming_const is added to xcan_devtype_data as CAN FD cores will
  have wider setting ranges.

- bus_clk clock name is now determined through xcan_devtype_data instead
  of comparing compatible string in probe().

- xcan_devtype_data is added to xcan_priv to allow flag checks after
  probe().

- XCAN_CAP_WATERMARK is now XCAN_FLAG_TXFEMP. CAN FD cores have
  watermark support but no TXFEMP interrupt, which is what we are
  actually interested in.

- xcan_start_xmit() is split to in two parts to prepare for TX mailboxes
  instead of FIFO in CAN FD cores.

v2: Wrapped some long lines in xcan_write_frame().

Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Cc: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2018-07-27 10:40:17 +02:00

1427 lines
39 KiB
C
Raw Blame History

/* 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_OFFSET = 0x30, /* TX FIFO base */
XCAN_RXFIFO_OFFSET = 0x50, /* RX FIFO base */
};
#define XCAN_FRAME_ID_OFFSET(frame_base) ((frame_base) + 0x00)
#define XCAN_FRAME_DLC_OFFSET(frame_base) ((frame_base) + 0x04)
#define XCAN_FRAME_DW1_OFFSET(frame_base) ((frame_base) + 0x08)
#define XCAN_FRAME_DW2_OFFSET(frame_base) ((frame_base) + 0x0C)
/* 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 */
/* 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)
/* TX-FIFO-empty interrupt available */
#define XCAN_FLAG_TXFEMP 0x0001
struct xcan_devtype_data {
unsigned int flags;
const struct can_bittiming_const *bittiming_const;
const char *bus_clk_name;
};
/**
* 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
* @devtype: Device type specific constants
*/
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;
struct xcan_devtype_data devtype;
};
/* 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,
};
/**
* 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_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);
/* 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_write_frame - Write a frame to HW
* @skb: sk_buff pointer that contains data to be Txed
* @frame_offset: Register offset to write the frame to
*/
static void xcan_write_frame(struct xcan_priv *priv, struct sk_buff *skb,
int frame_offset)
{
u32 id, dlc, data[2] = {0, 0};
struct can_frame *cf = (struct can_frame *)skb->data;
/* 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));
priv->write_reg(priv, XCAN_FRAME_ID_OFFSET(frame_offset), id);
/* If the CAN frame is RTR frame this write triggers transmission */
priv->write_reg(priv, XCAN_FRAME_DLC_OFFSET(frame_offset), dlc);
if (!(cf->can_id & CAN_RTR_FLAG)) {
priv->write_reg(priv, XCAN_FRAME_DW1_OFFSET(frame_offset),
data[0]);
/* If the CAN frame is Standard/Extended frame this
* write triggers transmission
*/
priv->write_reg(priv, XCAN_FRAME_DW2_OFFSET(frame_offset),
data[1]);
}
}
/**
* xcan_start_xmit_fifo - Starts the transmission (FIFO mode)
*
* Return: 0 on success, -ENOSPC if FIFO is full.
*/
static int xcan_start_xmit_fifo(struct sk_buff *skb, struct net_device *ndev)
{
struct xcan_priv *priv = netdev_priv(ndev);
unsigned long flags;
/* Check if the TX buffer is full */
if (unlikely(priv->read_reg(priv, XCAN_SR_OFFSET) &
XCAN_SR_TXFLL_MASK))
return -ENOSPC;
can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max);
spin_lock_irqsave(&priv->tx_lock, flags);
priv->tx_head++;
xcan_write_frame(priv, skb, XCAN_TXFIFO_OFFSET);
/* 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 0;
}
/**
* 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: NETDEV_TX_OK on success and NETDEV_TX_BUSY when the tx queue is full
*/
static int xcan_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
int ret;
if (can_dropped_invalid_skb(ndev, skb))
return NETDEV_TX_OK;
ret = xcan_start_xmit_fifo(skb, ndev);
if (ret < 0) {
netdev_err(ndev, "BUG!, TX full when queue awake!\n");
netif_stop_queue(ndev);
return NETDEV_TX_BUSY;
}
return NETDEV_TX_OK;
}
/**
* xcan_rx - Is called from CAN isr to complete the received
* frame processing
* @ndev: Pointer to net_device structure
* @frame_base: Register offset to the frame to be read
*
* 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, int frame_base)
{
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_FRAME_ID_OFFSET(frame_base));
dlc = priv->read_reg(priv, XCAN_FRAME_DLC_OFFSET(frame_base)) >>
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_FRAME_DW1_OFFSET(frame_base));
data[1] = priv->read_reg(priv, XCAN_FRAME_DW2_OFFSET(frame_base));
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;
enum can_state tx_state = txerr >= rxerr ? new_state : 0;
enum can_state rx_state = txerr <= rxerr ? new_state : 0;
/* non-ERROR states are handled elsewhere */
if (WARN_ON(new_state > CAN_STATE_ERROR_PASSIVE))
return;
can_change_state(ndev, cf, tx_state, rx_state);
if (cf) {
cf->data[6] = txerr;
cf->data[7] = rxerr;
}
}
/**
* 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);
if (new_state != priv->can.state)
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, XCAN_RXFIFO_OFFSET);
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_done(napi, work_done);
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--) {
stats->tx_bytes += 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 = {
.flags = XCAN_FLAG_TXFEMP,
.bittiming_const = &xcan_bittiming_const,
.bus_clk_name = "pclk",
};
static const struct xcan_devtype_data xcan_axi_data = {
.flags = 0,
.bittiming_const = &xcan_bittiming_const,
.bus_clk_name = "s_axi_aclk",
};
/* 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", .data = &xcan_axi_data },
{ /* 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;
const struct xcan_devtype_data *devtype = &xcan_axi_data;
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 && of_id->data)
devtype = of_id->data;
/* 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 (devtype->flags & XCAN_FLAG_TXFEMP)
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 = devtype->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;
priv->devtype = *devtype;
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;
}
priv->bus_clk = devm_clk_get(&pdev->dev, devtype->bus_clk_name);
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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