Re: [PATCH] can: xilinx CAN controller support.

From: Marc Kleine-Budde
Date: Thu Feb 06 2014 - 07:41:35 EST

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In reply to: Kedareswara rao Appana: "[PATCH] can: xilinx CAN controller support."
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On 02/06/2014 11:19 AM, Kedareswara rao Appana wrote:
> This patch adds xilinx CAN controller support.
> This driver supports both ZYNQ CANPS IP and
> Soft IP AXI CAN controller.
>
> Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx>

First review, see comments inline.

Marc

> ---
> This patch is rebased on the 3.14 rc1 kernel.
> ---
> .../devicetree/bindings/net/can/xilinx_can.txt | 43 +
> drivers/net/can/Kconfig | 8 +
> drivers/net/can/Makefile | 1 +
> drivers/net/can/xilinx_can.c | 1150 ++++++++++++++++++++
> 4 files changed, 1202 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/net/can/xilinx_can.txt
> create mode 100644 drivers/net/can/xilinx_can.c
>
> diff --git a/Documentation/devicetree/bindings/net/can/xilinx_can.txt b/Documentation/devicetree/bindings/net/can/xilinx_can.txt
> new file mode 100644
> index 0000000..34f9643
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/can/xilinx_can.txt
> @@ -0,0 +1,43 @@
> +Xilinx Axi CAN/Zynq CANPS controller Device Tree Bindings
> +---------------------------------------------------------
> +
> +Required properties:
> +- compatible : Should be "xlnx,zynq-can-1.00.a" for Zynq CAN
> + controllers and "xlnx,axi-can-1.00.a" for Axi CAN
> + controllers.
> +- reg : Physical base address and size of the Axi CAN/Zynq
> + CANPS registers map.
> +- interrupts : Property with a value describing the interrupt
> + number.
> +- interrupt-parent : Must be core interrupt controller
> +- clock-names : List of input clock names - "ref_clk", "aper_clk"
> + (See clock bindings for details. Two clocks are
> + required for Zynq CAN. For Axi CAN
> + case it is one(ref_clk)).
> +- clocks : Clock phandles (see clock bindings for details).
> +- xlnx,can-tx-dpth : Can Tx fifo depth (Required for Axi CAN).
> +- xlnx,can-rx-dpth : Can Rx fifo depth (Required for Axi CAN).
> +
> +
> +Example:
> +
> +For Zynq CANPS Dts file:
> + zynq_can_0: zynq-can@e0008000 {
> + compatible = "xlnx,zynq-can-1.00.a";
> + clocks = <&clkc 19>, <&clkc 36>;
> + clock-names = "ref_clk", "aper_clk";
> + reg = <0xe0008000 0x1000>;
> + interrupts = <0 28 4>;
> + interrupt-parent = <&intc>;

Above xlnx,can-{rx,tx}-dpth is mentioned as required, but it's not in
the Zynq example.

> + };
> +For Axi CAN Dts file:
> + axi_can_0: axi-can@40000000 {
> + compatible = "xlnx,axi-can-1.00.a";
> + clocks = <&clkc 0>;
> + clock-names = "ref_clk" ;
> + reg = <0x40000000 0x10000>;
> + interrupt-parent = <&intc>;
> + interrupts = <0 59 1>;
> + xlnx,can-tx-dpth = <0x40>;
> + xlnx,can-rx-dpth = <0x40>;
> + };
> diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
> index d447b88..2344fb5 100644
> --- a/drivers/net/can/Kconfig
> +++ b/drivers/net/can/Kconfig
> @@ -125,6 +125,14 @@ 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
> + default n

"default n" is default, please remove.

> + ---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..c1b2b9d
> --- /dev/null
> +++ b/drivers/net/can/xilinx_can.c
> @@ -0,0 +1,1150 @@
> +/* 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#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 */
> +#define XCAN_SRR_OFFSET 0x00 /* Software reset */
> +#define XCAN_MSR_OFFSET 0x04 /* Mode select */
> +#define XCAN_BRPR_OFFSET 0x08 /* Baud rate prescaler */
> +#define XCAN_BTR_OFFSET 0x0C /* Bit timing */
> +#define XCAN_ECR_OFFSET 0x10 /* Error counter */
> +#define XCAN_ESR_OFFSET 0x14 /* Error status */
> +#define XCAN_SR_OFFSET 0x18 /* Status */
> +#define XCAN_ISR_OFFSET 0x1C /* Interrupt status */
> +#define XCAN_IER_OFFSET 0x20 /* Interrupt enable */
> +#define XCAN_ICR_OFFSET 0x24 /* Interrupt clear */
> +#define XCAN_TXFIFO_ID_OFFSET 0x30 /* TX FIFO ID */
> +#define XCAN_TXFIFO_DLC_OFFSET 0x34 /* TX FIFO DLC */
> +#define XCAN_TXFIFO_DW1_OFFSET 0x38 /* TX FIFO Data Word 1 */
> +#define XCAN_TXFIFO_DW2_OFFSET 0x3C /* TX FIFO Data Word 2 */
> +#define XCAN_RXFIFO_ID_OFFSET 0x50 /* RX FIFO ID */
> +#define XCAN_RXFIFO_DLC_OFFSET 0x54 /* RX FIFO DLC */
> +#define XCAN_RXFIFO_DW1_OFFSET 0x58 /* RX FIFO Data Word 1 */
> +#define 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_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_ECHO_SKB_MAX 64
> +#define XCAN_NAPI_WEIGHT 64
> +#define XCAN_FRAME_MAX_DATA_LEN 8
> +#define XCAN_TIMEOUT (50 * HZ)
> +
> +/**
> + * struct xcan_priv - This definition define CAN driver instance
> + * @can: CAN private data structure.
> + * @open_time: For holding timeout values
> + * @waiting_ech_skb_index: Pointer for skb
> + * @ech_skb_next: This tell the next packet in the queue
> + * @waiting_ech_skb_num: Gives the number of packets waiting
> + * @xcan_echo_skb_max_tx: Maximum number packets the driver can send
> + * @xcan_echo_skb_max_rx: Maximum number packets the driver can receive
> + * @napi: NAPI structure
> + * @ech_skb_lock: For spinlock purpose
> + * @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()
> + * @aperclk: Pointer to struct clk
> + * @devclk: Pointer to struct clk
> + */
> +struct xcan_priv {
> + struct can_priv can;
> + int open_time;
> + int waiting_ech_skb_index;
> + int ech_skb_next;
> + int waiting_ech_skb_num;
> + int xcan_echo_skb_max_tx;
> + int xcan_echo_skb_max_rx;
> + struct napi_struct napi;
> + spinlock_t ech_skb_lock;
> + u32 (*read_reg)(const struct xcan_priv *priv, int reg);
> + void (*write_reg)(const struct xcan_priv *priv, int reg, u32 val);

Why do you have {read,write}_reg function here?

> + struct net_device *dev;
> + void __iomem *reg_base;
> + unsigned long irq_flags;
> + struct clk *aperclk;
> + struct clk *devclk;
> +};
> +
> +/* CAN Bittiming constants as per Xilinx CAN specs */
> +static 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 - Write a value to the device register
> + * @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(const struct xcan_priv *priv, int reg, u32 val)
> +{
> + writel(val, priv->reg_base + reg);
> +}
> +
> +/**
> + * xcan_read_reg - Read a value from the device register
> + * @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(const struct xcan_priv *priv, int reg)
> +{
> + return readl(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->can.state = CAN_STATE_STOPPED;
> + priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_OFFSET);
> +
> + timeout = jiffies + XCAN_TIMEOUT;
> + while (!(priv->read_reg(priv, XCAN_SR_OFFSET) & XCAN_SR_CONFIG_MASK)) {
> + if (time_after(jiffies, timeout)) {
> + netdev_warn(ndev, "timedout waiting for config mode\n");
> + return -ETIMEDOUT;
> + }
> + schedule_timeout(1);

better use usleep_range()

> + }
> +
> + 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,
> + "Cannot set bittiming can is not in config mode\n");
> + return -EPERM;
> + }
> +
> + netdev_dbg(ndev, "brp=%d,prop=%d,phase_seg1:%d,phase_reg2=%d,sjw=%d\n",
> + bt->brp, bt->prop_seg, bt->phase_seg1, bt->phase_seg2,
> + bt->sjw);

I think this dbg can be removed, as it just prints the userspace values.

> +
> + /* Setting Baud Rate prescalar value in BRPR Register */
> + btr0 = (bt->brp - 1) & XCAN_BRPR_BRP_MASK;
> +
> + /* Setting Time Segment 1 in BTR Register */
> + btr1 = (bt->prop_seg + bt->phase_seg1 - 1) & XCAN_BTR_TS1_MASK;
> +
> + /* Setting Time Segment 2 in BTR Register */
> + btr1 |= ((bt->phase_seg2 - 1) << XCAN_BTR_TS2_SHIFT) &
> + XCAN_BTR_TS2_MASK;
> +
> + /* Setting Synchronous jump width in BTR Register */
> + btr1 |= ((bt->sjw - 1) << XCAN_BTR_SJW_SHIFT) & XCAN_BTR_SJW_MASK;
> +
> + if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
> + netdev_info(ndev, "Doesn't support Triple Sampling\n");

no need to check, it's not passed to the driver until you advertise you
support it (see priv->can.ctrlmode_supported).

> + netdev_dbg(ndev, "Setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
> +
> + 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));

One of the dbg should be enough.

> +
> + return 0;
> +}
> +
> +/**
> + * xcan_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 always
> + */
> +static int xcan_start(struct net_device *ndev)
> +{
> + struct xcan_priv *priv = netdev_priv(ndev);
> +
> + /* Check if it is in reset mode */
> + if (priv->can.state != CAN_STATE_STOPPED)
> + set_reset_mode(ndev);

Please check return value of set_reset_mode

> +
> + /* 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)
> + /* Put device into loopback mode */
> + priv->write_reg(priv, XCAN_MSR_OFFSET, XCAN_MSR_LBACK_MASK);
> + else
> + /* The device is in normal mode */
> + priv->write_reg(priv, XCAN_MSR_OFFSET, 0);
> +
> + if (priv->can.state == CAN_STATE_STOPPED) {

I think your driver is always in CAN_STATE_STOPPED, right?

> + /* Enable Xilinx CAN */
> + priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_CEN_MASK);
> + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> + if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
> + while ((priv->read_reg(priv, XCAN_SR_OFFSET) &
> + XCAN_SR_LBACK_MASK) == 0)
> + ;
> + } else {
> + while ((priv->read_reg(priv, XCAN_SR_OFFSET)
> + & XCAN_SR_NORMAL_MASK) == 0)
> + ;

Please add a timeout to the loops.

> + }
> + 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)
> +{
> + struct xcan_priv *priv = netdev_priv(ndev);
> + int ret;
> +
> + netdev_dbg(ndev, "Setting the mode of the driver%s\n", __func__);

please remove dbg

> +
> + if (!priv->open_time)
> + return -EINVAL;

please remove open_time completely.

> +
> + switch (mode) {
> + case CAN_MODE_START:
> + ret = xcan_start(ndev);
> + if (ret < 0)
> + netdev_err(ndev, "xcan_start failed!\n");
> +
> + if (netif_queue_stopped(ndev))
> + netif_wake_queue(ndev);

just call wake_queue
> + 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, tmp_dw1, tmp_dw2 = 0, data1, data2 = 0;
> + unsigned long flags;
> +

Please add here:

if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;

> + /* Check if the TX buffer is full */
> + if (priv->read_reg(priv, XCAN_SR_OFFSET) & XCAN_SR_TXFLL_MASK) {
> + netif_stop_queue(ndev);
> + netdev_err(ndev, "TX register is still full!\n");
> + return NETDEV_TX_BUSY;
> + } else if (priv->waiting_ech_skb_num == priv->xcan_echo_skb_max_tx) {
> + netif_stop_queue(ndev);
> + netdev_err(ndev, "waiting:0x%08x, max:0x%08x\n",
> + priv->waiting_ech_skb_num, priv->xcan_echo_skb_max_tx);
> + return NETDEV_TX_BUSY;
> + }

You should handle flow control after you put the CAN frame into the
hardware, but before activating the TX complete interrutp.

> + /* Watch carefully on the bit sequence */
> + if ((cf->can_id & CAN_EFF_FLAG) == 0) {

Nitpick easier to read is:

if (cf->can_id & CAN_EFF_FLAG) {
/* EFF handling */
} else {
/* STD handling */
}

> + /* 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)
> + /* Extended frames remote TX request */
> + id |= XCAN_IDR_SRR_MASK;
> + } else {
> + /* 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;
> + }
> +
> + dlc = (cf->can_dlc & 0xf) << XCAN_DLCR_DLC_SHIFT;

With the above check can_dlc is valid.

> +
> + tmp_dw1 = le32_to_cpup((u32 *)(cf->data));
> + data1 = htonl(tmp_dw1);

This looks broken. cf->data is in big endian, what is the endianess of
your registers?

> + if (dlc > 4) {
> + tmp_dw2 = le32_to_cpup((u32 *)(cf->data + 4));
> + data2 = htonl(tmp_dw2);
> + }
> +
> + netdev_dbg(ndev, "tx:id=0x%08x,dlc=0x%08x,d1=0x%08x,d2=0x%08x\n",
> + id, dlc, data1, data2);

please remove the dbg

> + /* Write the Frame to Xilinx CAN TX FIFO */
> + priv->write_reg(priv, XCAN_TXFIFO_ID_OFFSET, id);
> + priv->write_reg(priv, XCAN_TXFIFO_DLC_OFFSET, dlc);
> + priv->write_reg(priv, XCAN_TXFIFO_DW1_OFFSET, data1);
> + priv->write_reg(priv, XCAN_TXFIFO_DW2_OFFSET, data2);

Which write triggers the transmission?

> + stats->tx_bytes += cf->can_dlc;

Can you move the tx_bytes += to your tx-complete routine?

> + ndev->trans_start = jiffies;

Please remove
> +
> + can_put_echo_skb(skb, ndev, priv->ech_skb_next);

This looks racy, first fill the echo_skb, then start the transmission.
> +
> + priv->ech_skb_next = (priv->ech_skb_next + 1) %
> + priv->xcan_echo_skb_max_tx;
> +
> + spin_lock_irqsave(&priv->ech_skb_lock, flags);
> + priv->waiting_ech_skb_num++;
> + spin_unlock_irqrestore(&priv->ech_skb_lock, flags);
> +

Please move the flow controll handling here.

> + 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: 0 on success and negative error value on error
> + */
> +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, data1, data2;
> +
> + skb = alloc_can_skb(ndev, &cf);
> + if (!skb)
> + return -ENOMEM;
> +
> + /* 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_MASK;
> + data1 = priv->read_reg(priv, XCAN_RXFIFO_DW1_OFFSET);
> + data2 = priv->read_reg(priv, XCAN_RXFIFO_DW2_OFFSET);

If you don't use data? below, don't read them in the first place. Better
move the read below, where you fill the data of the can_frame.

> + netdev_dbg(ndev, "rx:id=0x%08x,dlc=0x%08x,d1=0x%08x,d2=0x%08x\n",
> + id_xcan, dlc, data1, data2);
>
please remove dbg

+
> + /* Change Xilinx CAN data length format to socketCAN data format */
> + cf->can_dlc = get_can_dlc((dlc & XCAN_DLCR_DLC_MASK) >>
> + XCAN_DLCR_DLC_SHIFT);
> +
> + /* 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_RTR_MASK)
> + cf->can_id |= CAN_RTR_FLAG;
> + }
> +
> + /* Change Xilinx CAN data format to socketCAN data format */

Don't fill cf->data if RTR is set. The endianess handling looks weird
here, too.

> + *(u32 *)(cf->data) = ntohl(data1);
> + if (cf->can_dlc > 4)
> + *(u32 *)(cf->data + 4) = ntohl(data2);
> + else
> + *(u32 *)(cf->data + 4) = 0;

no need to set to zero

> + stats->rx_bytes += cf->can_dlc;

please group rx_bytes and rx_packets handling
> +
> + can_led_event(ndev, CAN_LED_EVENT_RX);
> +
> + netif_receive_skb(skb);
> +
> + stats->rx_packets++;
> + return 0;
> +}
> +
> +/**
> + * 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;
> +
> + skb = alloc_can_err_skb(ndev, &cf);
> + if (!skb) {
> + netdev_err(ndev, "alloc_can_err_skb() failed!\n");
> + return;
> + }
> +
> + err_status = priv->read_reg(priv, XCAN_ESR_OFFSET);
> + priv->write_reg(priv, XCAN_ESR_OFFSET, err_status);
> + status = priv->read_reg(priv, XCAN_SR_OFFSET);
> +
> + if (isr & XCAN_IXR_BSOFF_MASK) {
> + priv->can.state = CAN_STATE_BUS_OFF;
> + cf->can_id |= CAN_ERR_BUSOFF;
> + 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);
> + } else if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK) {
> + cf->can_id |= CAN_ERR_CRTL;
> + priv->can.state = CAN_STATE_ERROR_PASSIVE;
> + priv->can.can_stats.error_passive++;
> + cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE |
> + CAN_ERR_CRTL_TX_PASSIVE;
> + } else if (status & XCAN_SR_ERRWRN_MASK) {
> + cf->can_id |= CAN_ERR_CRTL;
> + priv->can.state = CAN_STATE_ERROR_WARNING;
> + priv->can.can_stats.error_warning++;
> + cf->data[1] |= CAN_ERR_CRTL_RX_WARNING |
> + CAN_ERR_CRTL_TX_WARNING;
> + }
> +
> + /* Check for Arbitration lost interrupt */
> + if (isr & XCAN_IXR_ARBLST_MASK) {
> + cf->can_id |= CAN_ERR_LOSTARB;
> + cf->data[0] = CAN_ERR_LOSTARB_UNSPEC;
> + priv->can.can_stats.arbitration_lost++;
> + }
> +
> + /* Check for RX FIFO Overflow interrupt */
> + if (isr & XCAN_IXR_RXOFLW_MASK) {
> + cf->can_id |= CAN_ERR_CRTL;
> + cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
> + stats->rx_over_errors++;
> + stats->rx_errors++;
> + priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
> + }
> +
> + /* Check for error interrupt */
> + if (isr & XCAN_IXR_ERROR_MASK) {
> + 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) {
> + cf->can_id |= CAN_ERR_ACK;
> + cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
> + stats->tx_errors++;
> + }
> +
> + /* Check for Bit error interrupt */
> + if (err_status & XCAN_ESR_BERR_MASK) {
> + cf->can_id |= CAN_ERR_PROT;
> + cf->data[2] = CAN_ERR_PROT_BIT;
> + stats->tx_errors++;
> + }
> +
> + /* Check for Stuff error interrupt */
> + if (err_status & XCAN_ESR_STER_MASK) {
> + cf->can_id |= CAN_ERR_PROT;
> + cf->data[2] = CAN_ERR_PROT_STUFF;
> + stats->rx_errors++;
> + }
> +
> + /* Check for Form error interrupt */
> + if (err_status & XCAN_ESR_FMER_MASK) {
> + cf->can_id |= CAN_ERR_PROT;
> + cf->data[2] = CAN_ERR_PROT_FORM;
> + stats->rx_errors++;
> + }
> +
> + /* Check for CRC error interrupt */
> + if (err_status & XCAN_ESR_CRCER_MASK) {
> + cf->can_id |= CAN_ERR_PROT;
> + cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ |
> + CAN_ERR_PROT_LOC_CRC_DEL;
> + stats->rx_errors++;
> + }
> + priv->can.can_stats.bus_error++;
> + }
> +
> + netif_rx(skb);
> + stats->rx_packets++;
> + stats->rx_bytes += cf->can_dlc;
> +
> + 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);
> + if (xcan_rx(ndev) < 0)
> + return work_done;
> + work_done++;
> + } 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 < 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
> + */
> +static void xcan_tx_interrupt(struct net_device *ndev)
> +{
> + unsigned long flags;
> + struct xcan_priv *priv = netdev_priv(ndev);
> + struct net_device_stats *stats = &ndev->stats;
> + u32 processed = 0, txpackets;
> +
> + stats->tx_packets++;
> + netdev_dbg(ndev, "%s: waiting total:%d,current:%d\n", __func__,
> + priv->waiting_ech_skb_num, priv->waiting_ech_skb_index);
> +
> + txpackets = priv->waiting_ech_skb_num;
> +
> + if (txpackets) {
> + can_get_echo_skb(ndev, priv->waiting_ech_skb_index);
> + priv->waiting_ech_skb_index =
> + (priv->waiting_ech_skb_index + 1) %
> + priv->xcan_echo_skb_max_tx;
> + processed++;
> + txpackets--;
> + }
> +
> + spin_lock_irqsave(&priv->ech_skb_lock, flags);
> + priv->waiting_ech_skb_num -= processed;
> + spin_unlock_irqrestore(&priv->ech_skb_lock, flags);
> +
> + netdev_dbg(ndev, "%s: waiting total:%d,current:%d\n", __func__,
> + priv->waiting_ech_skb_num, priv->waiting_ech_skb_index);
> +
> + netif_wake_queue(ndev);
> +
> + can_led_event(ndev, CAN_LED_EVENT_TX);
> +}
> +
> +/**
> + * 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;
> +
> + if (priv->can.state == CAN_STATE_STOPPED)

This should not happen, please remove.

> + return IRQ_NONE;
> +
> + /* Get the interrupt status from Xilinx CAN */
> + isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
> + if (!isr)
> + return IRQ_NONE;
> +
> + netdev_dbg(ndev, "%s: isr:#x%08x, err:#x%08x\n", __func__,
> + isr, priv->read_reg(priv, XCAN_ESR_OFFSET));
> +
> + /* 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) {
> + priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK);
> + xcan_tx_interrupt(ndev);
> + }
> +
> + /* 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_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_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 err;
> +
> + /* Set chip into reset mode */
> + err = set_reset_mode(ndev);
> + if (err < 0)
> + netdev_err(ndev, "mode resetting failed failed!\n");
> +
> + /* Common open */
> + err = open_candev(ndev);
> + if (err)
> + return err;
> +
> + err = xcan_start(ndev);
> + if (err < 0)
> + netdev_err(ndev, "xcan_start failed!\n");
> +
> +
> + can_led_event(ndev, CAN_LED_EVENT_OPEN);
> + napi_enable(&priv->napi);
> + netif_start_queue(ndev);
> +
> + return 0;
> +}
> +
> +/**
> + * 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_stop(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 always
> + */
> +static int xcan_get_berr_counter(const struct net_device *ndev,
> + struct can_berr_counter *bec)
> +{
> + struct xcan_priv *priv = netdev_priv(ndev);
> +
> + 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);
> + 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,
> +};
> +
> +#ifdef CONFIG_PM_SLEEP
> +/**
> + * 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 xcan_suspend(struct device *_dev)
> +{
> + struct platform_device *pdev = container_of(_dev,
> + struct platform_device, 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->aperclk);
> + clk_disable(priv->devclk);
> +
> + 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 xcan_resume(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev,
> + struct platform_device, dev);
> + struct net_device *ndev = platform_get_drvdata(pdev);
> + struct xcan_priv *priv = netdev_priv(ndev);
> + int ret;
> +
> + ret = clk_enable(priv->aperclk);
> + if (ret) {
> + dev_err(dev, "Cannot enable clock.\n");
> + return ret;
> + }
> + ret = clk_enable(priv->devclk);
> + if (ret) {
> + dev_err(dev, "Cannot enable clock.\n");
> + 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;
> +}
> +#endif
> +
> +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;
> + int ret, fifodep;
> +
> + /* Create a CAN device instance */
> + ndev = alloc_candev(sizeof(struct xcan_priv), XCAN_ECHO_SKB_MAX);
> + if (!ndev)
> + return -ENOMEM;
> +
> + priv = netdev_priv(ndev);
> + priv->dev = ndev;
> + priv->can.bittiming_const = &xcan_bittiming_const;
> + priv->can.do_set_bittiming = xcan_set_bittiming;
> + 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->xcan_echo_skb_max_tx = XCAN_ECHO_SKB_MAX;
> + priv->xcan_echo_skb_max_rx = XCAN_NAPI_WEIGHT;
> +
> + /* Get IRQ for the device */
> + ndev->irq = platform_get_irq(pdev, 0);
> + ret = devm_request_irq(&pdev->dev, ndev->irq, &xcan_interrupt,
> + priv->irq_flags, dev_name(&pdev->dev),
> + (void *)ndev);

We usually request the interrupt on in the open() function

> + if (ret < 0) {
> + dev_err(&pdev->dev, "Irq allocation for CAN failed\n");
> + goto err_free;
> + }
> +
> + spin_lock_init(&priv->ech_skb_lock);
> + 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;
> +
> + /* Get the virtual base address for the device */
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + priv->reg_base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(priv->reg_base)) {
> + ret = PTR_ERR(priv->reg_base);
> + goto err_free;
> + }
> + ndev->mem_start = res->start;
> + ndev->mem_end = res->end;
> +
> + priv->write_reg = xcan_write_reg;
> + priv->read_reg = xcan_read_reg;
> +
> + /* Getting the CAN devclk info */
> + priv->devclk = devm_clk_get(&pdev->dev, "ref_clk");
> + if (IS_ERR(priv->devclk)) {
> + dev_err(&pdev->dev, "Device clock not found.\n");
> + ret = PTR_ERR(priv->devclk);
> + goto err_free;
> + }
> +
> + /* Check for type of CAN device */
> + if (of_device_is_compatible(pdev->dev.of_node,
> + "xlnx,zynq-can-1.00.a")) {
> + priv->aperclk = devm_clk_get(&pdev->dev, "aper_clk");
> + if (IS_ERR(priv->aperclk)) {
> + dev_err(&pdev->dev, "aper clock not found\n");
> + ret = PTR_ERR(priv->aperclk);
> + goto err_free;
> + }
> + } else {
> + priv->aperclk = priv->devclk;
> + ret = of_property_read_u32(pdev->dev.of_node,
> + "xlnx,can-tx-dpth", &fifodep);
> + if (ret < 0)
> + goto err_free;
> + priv->xcan_echo_skb_max_tx = fifodep;
> + ret = of_property_read_u32(pdev->dev.of_node,
> + "xlnx,can-rx-dpth", &fifodep);
> + if (ret < 0)
> + goto err_free;
> + priv->xcan_echo_skb_max_rx = fifodep;
> + }
> +
> + ret = clk_prepare_enable(priv->devclk);
> + if (ret) {
> + dev_err(&pdev->dev, "unable to enable device clock\n");
> + goto err_free;
> + }
> +
> + ret = clk_prepare_enable(priv->aperclk);
> + if (ret) {
> + dev_err(&pdev->dev, "unable to enable aper clock\n");
> + goto err_unprepar_disabledev;
> + }
> +
> + priv->can.clock.freq = clk_get_rate(priv->devclk);
> +
> + netif_napi_add(ndev, &priv->napi, xcan_rx_poll,
> + priv->xcan_echo_skb_max_rx);
> + ret = register_candev(ndev);
> + if (ret) {
> + dev_err(&pdev->dev, "fail to register failed (err=%d)\n", ret);
> + goto err_unprepar_disableaper;
> + }
> +
> + devm_can_led_init(ndev);
> + dev_info(&pdev->dev,
> + "reg_base=0x%p irq=%d clock=%d, tx fifo depth:%d\n",
> + priv->reg_base, ndev->irq, priv->can.clock.freq,
> + priv->xcan_echo_skb_max_tx);
> +
> + return 0;
> +
> +err_unprepar_disableaper:
> + clk_disable_unprepare(priv->aperclk);
> +err_unprepar_disabledev:
> + clk_disable_unprepare(priv->devclk);
> +err_free:
> + free_candev(ndev);
> +
> + 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);
> + clk_disable_unprepare(priv->aperclk);
> + clk_disable_unprepare(priv->devclk);
> +
> + free_candev(ndev);
> +
> + return 0;
> +}
> +
> +/* Match table for OF platform binding */
> +static struct of_device_id xcan_of_match[] = {
> + { .compatible = "xlnx,zynq-can-1.00.a", },
> + { .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");
>

--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |

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