[PATCH v8 2/2] can: xilinx CAN controller support.

Kedareswara rao Appana
2014-05-21T07:00:59Z

This patch adds xilinx CAN controller support.
This driver supports both ZYNQ CANPS and Soft IP
AXI CAN controller.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
---
Changes for v8:
- call can_led_event only once in xcan_tx_interrupt();
- proceed with error handling if alloc_can_err_skb() failed in xcan_err_interrupt
- stop using 'cf' after netif_{rx|receive_skb}() calls;
- Modify the xcan_tx_interrupt loop logic as per Marc Suggestion;
Changes for v7:
- Updated the driver with review comments.
- Moved the driver bindings doc as a separte patch.
Changes for v6:
- Updated the driver with review comments.
- Used the clock names specified in the data sheet.
- Updated the devicetree bindings doc as per Rob suggestion.
Changes for v5:
- Updated the driver with the review comments.
- Remove the check for the tx fifo full interrupt condition
form Tx interrupt routine as we are checking it in the _xmit
routine.
- Clearing the txok interrupt in the tx interrupt routine for
every Tx can frame.
Changes for v4:
- Added check for the tx fifo full interrupt condition in
Tx interrupt routine.
- Added be iohelper functions.
- Moved the clock enable/disable to probe/remove because of
Added big endian support for AXI CAN controller case(reading
a register during probe for that we need to enable clock).
Changes for v3:
- Updated the driver with the review comments.
- Modified the tranmit logic as per Marc suggestion.
- Enabling the clock when the interface is up to reduce the
Power consumption.
Changes for v2:
- Updated with the review comments.
- Removed the unnecessary debug prints.
- include tx,rx fifo depths in ZYNQ CANPS case also.
---
drivers/net/can/Kconfig | 7 +
drivers/net/can/Makefile | 1 +
drivers/net/can/xilinx_can.c | 1208 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 1216 insertions(+), 0 deletions(-)
create mode 100644 drivers/net/can/xilinx_can.c

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index 9e7d95d..9049884 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -125,6 +125,13 @@ config CAN_GRCAN
endian syntheses of the cores would need some modifications on
the hardware level to work.

+config CAN_XILINXCAN
+ tristate "Xilinx CAN"
+ depends on ARCH_ZYNQ || MICROBLAZE || COMPILE_TEST
+ depends on COMMON_CLK && HAS_IOMEM
+ ---help---
+ Xilinx CAN driver. This driver supports both soft AXI CAN IP and
+ Zynq CANPS IP.
source "drivers/net/can/mscan/Kconfig"

source "drivers/net/can/sja1000/Kconfig"
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index c744039..0b8e11e 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -25,5 +25,6 @@ obj-$(CONFIG_CAN_JANZ_ICAN3) += janz-ican3.o
obj-$(CONFIG_CAN_FLEXCAN) += flexcan.o
obj-$(CONFIG_PCH_CAN) += pch_can.o
obj-$(CONFIG_CAN_GRCAN) += grcan.o
+obj-$(CONFIG_CAN_XILINXCAN) += xilinx_can.o

ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
new file mode 100644
index 0000000..5e8b560
--- /dev/null
+++ b/drivers/net/can/xilinx_can.c
@@ -0,0 +1,1208 @@
+/* Xilinx CAN device driver
+ *
+ * Copyright (C) 2012 - 2014 Xilinx, Inc.
+ * Copyright (C) 2009 PetaLogix. All rights reserved.
+ *
+ * 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/platform_device.h>
+#include <linux/skbuff.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/can/led.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_ARBLST_MASK | XCAN_IXR_RXOK_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_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;
+ 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 net_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,
+};
+
+/**
+ * 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);
+ }
+
+ 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 err, reg_msr, reg_sr_mask;
+ 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};
+
+ 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);
+ 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;
+ }
+
+ /* Check if the TX buffer is full */
+ if ((priv->tx_head - priv->tx_tail) == priv->tx_max)
+ netif_stop_queue(ndev);
+
+ 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;
+ }
+
+ if (!(id_xcan & XCAN_IDR_SRR_MASK)) {
+ data[0] = priv->read_reg(priv, XCAN_RXFIFO_DW1_OFFSET);
+ data[1] = priv->read_reg(priv, XCAN_RXFIFO_DW2_OFFSET);
+
+ /* 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_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, status, txerr = 0, rxerr = 0;
+
+ 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);
+ txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) & XCAN_ECR_TEC_MASK;
+ rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) &
+ XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT);
+ status = priv->read_reg(priv, XCAN_SR_OFFSET);
+
+ 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 if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK) {
+ priv->can.state = CAN_STATE_ERROR_PASSIVE;
+ priv->can.can_stats.error_passive++;
+ if (skb) {
+ cf->can_id |= CAN_ERR_CRTL;
+ cf->data[1] = (rxerr > 127) ?
+ CAN_ERR_CRTL_RX_PASSIVE :
+ CAN_ERR_CRTL_TX_PASSIVE;
+ cf->data[6] = txerr;
+ cf->data[7] = rxerr;
+ }
+ } else if (status & XCAN_SR_ERRWRN_MASK) {
+ priv->can.state = CAN_STATE_ERROR_WARNING;
+ priv->can.can_stats.error_warning++;
+ if (skb) {
+ cf->can_id |= CAN_ERR_CRTL;
+ cf->data[1] |= (txerr > rxerr) ?
+ CAN_ERR_CRTL_TX_WARNING :
+ CAN_ERR_CRTL_RX_WARNING;
+ cf->data[6] = txerr;
+ cf->data[7] = rxerr;
+ }
+ }
+
+ /* 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++;
+ priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
+ 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;
+ cf->data[2] |= CAN_ERR_PROT_UNSPEC;
+ }
+
+ /* 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 |
+ CAN_ERR_PROT_LOC_CRC_DEL;
+ }
+ }
+ 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)) {
+ if (isr & XCAN_IXR_RXOK_MASK) {
+ priv->write_reg(priv, XCAN_ICR_OFFSET,
+ XCAN_IXR_RXOK_MASK);
+ work_done += xcan_rx(ndev);
+ } else {
+ priv->write_reg(priv, XCAN_ICR_OFFSET,
+ XCAN_IXR_RXNEMP_MASK);
+ break;
+ }
+ 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);
+
+ if (work_done < quota) {
+ napi_complete(napi);
+ ier = priv->read_reg(priv, XCAN_IER_OFFSET);
+ ier |= (XCAN_IXR_RXOK_MASK | 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;
+
+ while ((priv->tx_head - priv->tx_tail > 0) &&
+ (isr & XCAN_IXR_TXOK_MASK)) {
+ priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK);
+ can_get_echo_skb(ndev, priv->tx_tail %
+ priv->tx_max);
+ priv->tx_tail++;
+ stats->tx_packets++;
+ isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
+ }
+ can_led_event(ndev, CAN_LED_EVENT_TX);
+ netif_wake_queue(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;
+
+ /* 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 */
+ if (isr & (XCAN_IXR_ERROR_MASK | XCAN_IXR_RXOFLW_MASK |
+ XCAN_IXR_BSOFF_MASK | XCAN_IXR_ARBLST_MASK)) {
+ priv->write_reg(priv, XCAN_ICR_OFFSET, (XCAN_IXR_ERROR_MASK |
+ XCAN_IXR_RXOFLW_MASK | XCAN_IXR_BSOFF_MASK |
+ XCAN_IXR_ARBLST_MASK));
+ xcan_err_interrupt(ndev, isr);
+ }
+
+ /* Check for the type of receive interrupt and Processing it */
+ if (isr & (XCAN_IXR_RXNEMP_MASK | XCAN_IXR_RXOK_MASK)) {
+ ier = priv->read_reg(priv, XCAN_IER_OFFSET);
+ ier &= ~(XCAN_IXR_RXNEMP_MASK | XCAN_IXR_RXOK_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);
+ u32 ier;
+
+ /* Disable interrupts and leave the can in configuration mode */
+ ier = priv->read_reg(priv, XCAN_IER_OFFSET);
+ ier &= ~XCAN_INTR_ALL;
+ priv->write_reg(priv, XCAN_IER_OFFSET, ier);
+ priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
+ 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 = 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;
+ }
+
+ ret = clk_prepare_enable(priv->can_clk);
+ if (ret) {
+ netdev_err(ndev, "unable to enable device clock\n");
+ goto err_irq;
+ }
+
+ ret = clk_prepare_enable(priv->bus_clk);
+ if (ret) {
+ netdev_err(ndev, "unable to enable bus clock\n");
+ goto err_can_clk;
+ }
+
+ /* Set chip into reset mode */
+ ret = set_reset_mode(ndev);
+ if (ret < 0) {
+ netdev_err(ndev, "mode resetting failed!\n");
+ goto err_bus_clk;
+ }
+
+ /* Common open */
+ ret = open_candev(ndev);
+ if (ret)
+ goto err_bus_clk;
+
+ 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_bus_clk:
+ clk_disable_unprepare(priv->bus_clk);
+err_can_clk:
+ clk_disable_unprepare(priv->can_clk);
+err_irq:
+ free_irq(ndev->irq, ndev);
+err:
+ 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);
+ clk_disable_unprepare(priv->bus_clk);
+ clk_disable_unprepare(priv->can_clk);
+ free_irq(ndev->irq, ndev);
+ close_candev(ndev);
+
+ can_led_event(ndev, CAN_LED_EVENT_STOP);
+
+ 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 = clk_prepare_enable(priv->can_clk);
+ if (ret)
+ goto err;
+
+ ret = clk_prepare_enable(priv->bus_clk);
+ if (ret)
+ goto err_clk;
+
+ 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);
+
+ clk_disable_unprepare(priv->bus_clk);
+ clk_disable_unprepare(priv->can_clk);
+
+ return 0;
+
+err_clk:
+ clk_disable_unprepare(priv->can_clk);
+err:
+ return ret;
+}
+
+
+static const struct net_device_ops xcan_netdev_ops = {
+ .ndo_open = xcan_open,
+ .ndo_stop = xcan_close,
+ .ndo_start_xmit = xcan_start_xmit,
+};
+
+/**
+ * xcan_suspend - Suspend method for the driver
+ * @dev: Address of the platform_device structure
+ *
+ * Put the driver into low power mode.
+ * Return: 0 always
+ */
+static int __maybe_unused xcan_suspend(struct device *dev)
+{
+ struct platform_device *pdev = dev_get_drvdata(dev);
+ struct net_device *ndev = platform_get_drvdata(pdev);
+ struct xcan_priv *priv = netdev_priv(ndev);
+
+ if (netif_running(ndev)) {
+ netif_stop_queue(ndev);
+ netif_device_detach(ndev);
+ }
+
+ priv->write_reg(priv, XCAN_MSR_OFFSET, XCAN_MSR_SLEEP_MASK);
+ priv->can.state = CAN_STATE_SLEEPING;
+
+ clk_disable(priv->bus_clk);
+ clk_disable(priv->can_clk);
+
+ return 0;
+}
+
+/**
+ * xcan_resume - Resume from suspend
+ * @dev: Address of the platformdevice structure
+ *
+ * Resume operation after suspend.
+ * Return: 0 on success and failure value on error
+ */
+static int __maybe_unused xcan_resume(struct device *dev)
+{
+ struct platform_device *pdev = dev_get_drvdata(dev);
+ struct net_device *ndev = platform_get_drvdata(pdev);
+ struct xcan_priv *priv = netdev_priv(ndev);
+ int ret;
+
+ ret = clk_enable(priv->bus_clk);
+ if (ret) {
+ dev_err(dev, "Cannot enable clock.\n");
+ return ret;
+ }
+ ret = clk_enable(priv->can_clk);
+ if (ret) {
+ dev_err(dev, "Cannot enable clock.\n");
+ clk_disable_unprepare(priv->bus_clk);
+ return ret;
+ }
+
+ priv->write_reg(priv, XCAN_MSR_OFFSET, 0);
+ priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_CEN_MASK);
+ priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+ if (netif_running(ndev)) {
+ netif_device_attach(ndev);
+ netif_start_queue(ndev);
+ }
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(xcan_dev_pm_ops, xcan_suspend, xcan_resume);
+
+/**
+ * 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;
+ void __iomem *addr;
+ int ret, rx_max, tx_max;
+
+ /* 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_max);
+ if (ret < 0)
+ goto err;
+
+ ret = of_property_read_u32(pdev->dev.of_node, "rx-fifo-depth", &rx_max);
+ if (ret < 0)
+ goto err;
+
+ /* Create a CAN device instance */
+ ndev = alloc_candev(sizeof(struct xcan_priv), tx_max);
+ if (!ndev)
+ return -ENOMEM;
+
+ priv = netdev_priv(ndev);
+ priv->dev = ndev;
+ 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;
+
+ /* 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;
+ }
+ }
+
+ ret = clk_prepare_enable(priv->can_clk);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to enable device clock\n");
+ goto err_free;
+ }
+
+ ret = clk_prepare_enable(priv->bus_clk);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to enable bus clock\n");
+ goto err_unprepare_disable_dev;
+ }
+
+ priv->write_reg = xcan_write_reg_le;
+ priv->read_reg = xcan_read_reg_le;
+
+ 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_unprepare_disable_busclk;
+ }
+
+ devm_can_led_init(ndev);
+ clk_disable_unprepare(priv->bus_clk);
+ clk_disable_unprepare(priv->can_clk);
+ netdev_dbg(ndev, "reg_base=0x%p irq=%d clock=%d, tx fifo depth:%d\n",
+ priv->reg_base, ndev->irq, priv->can.clock.freq,
+ priv->tx_max);
+
+ return 0;
+
+err_unprepare_disable_busclk:
+ clk_disable_unprepare(priv->bus_clk);
+err_unprepare_disable_dev:
+ clk_disable_unprepare(priv->can_clk);
+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);
+
+ if (set_reset_mode(ndev) < 0)
+ netdev_err(ndev, "mode resetting failed!\n");
+
+ unregister_candev(ndev);
+ netif_napi_del(&priv->napi);
+ free_candev(ndev);
+
+ return 0;
+}
+
+/* Match table for OF platform binding */
+static struct of_device_id xcan_of_match[] = {
+ { .compatible = "xlnx,zynq-can-1.0", },
+ { .compatible = "xlnx,axi-can-1.00.a", },
+ { /* end of list */ },
+};
+MODULE_DEVICE_TABLE(of, xcan_of_match);
+
+static struct platform_driver xcan_driver = {
+ .probe = xcan_probe,
+ .remove = xcan_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .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");
--
1.7.4