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Message-ID: <957b07ca-f74c-47fb-963a-084710d48c5a@AM1EHSMHS014.ehs.local>
Date: Tue, 22 Apr 2014 10:06:10 +0000
From: Appana Durga Kedareswara Rao <appana.durga.rao@...inx.com>
To: Marc Kleine-Budde <mkl@...gutronix.de>,
"wg@...ndegger.com" <wg@...ndegger.com>,
Michal Simek <michals@...inx.com>,
"grant.likely@...aro.org" <grant.likely@...aro.org>,
"robh+dt@...nel.org" <robh+dt@...nel.org>
CC: "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [PATCH v7 1/2] can: xilinx CAN controller support
Hi Marc,
> -----Original Message-----
> From: Marc Kleine-Budde [mailto:mkl@...gutronix.de]
> Sent: Tuesday, April 22, 2014 2:25 PM
> To: Appana Durga Kedareswara Rao; wg@...ndegger.com; Michal Simek;
> grant.likely@...aro.org; robh+dt@...nel.org
> Cc: linux-can@...r.kernel.org; netdev@...r.kernel.org; linux-arm-
> kernel@...ts.infradead.org; linux-kernel@...r.kernel.org;
> devicetree@...r.kernel.org; Appana Durga Kedareswara Rao
> Subject: Re: [PATCH v7 1/2] can: xilinx CAN controller support
>
> On 04/02/2014 03:13 PM, Kedareswara rao Appana wrote:
> > This patch adds xilinx CAN controller support.
> > This driver supports both ZYNQ CANPS and Soft IP AXI CAN controller.
>
> Meanwhile Thomas Gleixner put some effort into the c_can driver and
> found some problems in most of the can driver. See comments inline.
>
Ok will look into that patches
> Marc
>
> >
> > Signed-off-by: Kedareswara rao Appana <appanad@...inx.com>
> > ---
> > 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 | 1176
> > ++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 1184 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..b1433ab
> > --- /dev/null
> > +++ b/drivers/net/can/xilinx_can.c
> > @@ -0,0 +1,1176 @@
> > +/* 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_RTR_MASK)
> > + cf->can_id |= CAN_RTR_FLAG;
> > + }
> > +
> > + if (!(id_xcan & XCAN_IDR_RTR_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]);
> > + }
> > + can_led_event(ndev, CAN_LED_EVENT_RX);
>
> Please move can_led_event to xcan_rx_poll(), so that it only called once.
>
Ok
> > +
> > + netif_receive_skb(skb);
> > +
> > + stats->rx_bytes += cf->can_dlc;
>
> Please don't touch "cf" after netif_receive_skb(), as skb may not be valaid
> anymore.
>
Ok
> > + stats->rx_packets++;
> > + 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;
> > +
> > + skb = alloc_can_err_skb(ndev, &cf);
> > + if (!skb) {
> > + netdev_err(ndev, "alloc_can_err_skb() failed!\n");
> > + return;
> > + }
>
> Thomas Gleixner patched the c_can driver, so that the stats, can_stats and
> the state is properly handled even if the allocation of the error skb fails.
>
OK
> > +
> > + 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;
>
> Don't touch cf after netif_rx()
>
Ok
> > +
> > + 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);
>
Ok
> > +
> > + 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) {
> > + priv->write_reg(priv, XCAN_ICR_OFFSET,
> XCAN_IXR_TXOK_MASK);
> > + if (!(isr & XCAN_IXR_TXOK_MASK))
> > + break;
>
> This looks broken. I assume you have to issue the XCAN_IXR_TXOK_MASK-
> write once per tx-completed CAN frame. If you enter this loop you write
> once, then isr is read, then you write again and may exit this loop if
> XCAN_IXR_TXOK_MASK is not set anymore.
>
I am entering into this Api only when I successfully transferred a frame
I didn't understand why the loop is broken?
Could you please explain me a little bit in detail.
I am clearing this interrupt XCAN_IXR_TXOK_MASK once I entered into this api
And I am doing the rest of the thing what you explained above.
> > + can_get_echo_skb(ndev, priv->tx_tail %
> > + priv->tx_max);
> > + priv->tx_tail++;
> > + stats->tx_packets++;
> > + can_led_event(ndev, CAN_LED_EVENT_TX);
>
> Please move led_event after the loop to keep the overhead low.
>
Ok
> > + isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
> > + }
> > + 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_bus_clk;
>
> You have to close the candev:
Ok
> 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()
Ok
> > +
> > +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 always
> > + */
> > +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");
>
> I think it makes sense to have a single name for the second clock, so that
> this if...else... is't needed at all.
>
One of the comments I got from the Soren is the clocks name should match the name's in the device datasheet.
For axi_can case the clock names is can_clk and s_axi_aclk
For canps case the clock names is can_clk and pclk.
If you want me to put a unique for the both I will do.
Thanks for reviewing the patch.
Regards,
Kedar.
> > + 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");
> >
>
>
> --
> 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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