zynq+linux+ramdisk can调试

由于采用ramdisk文件系统，自带的ip工具版本太旧无法配置can，需要自行编译ip，具体参见参考文献2

1.vivado配置ps

2.设备树增加can0，一般开发板均已提供此配置

can@e0008000 {

			compatible = "xlnx,zynq-can-1.0";

			status = "okay";

			clocks = <0x1 0x13 0x1 0x24>;

			clock-names = "can_clk", "pclk";

			reg = <0xe0008000 0x1000>;

			interrupts = <0x0 0x1c 0x4>;

			interrupt-parent = <0x3>;

			tx-fifo-depth = <0x40>;

			rx-fifo-depth = <0x40>;

		};

3.kernel配置，一般已配好，具体参见参考文献1

4.测试

# ifconfig -a

can0      Link encap:UNSPEC  HWaddr ---------------

          NOARP  MTU:  Metric:

          RX packets: errors: dropped: overruns: frame:

          TX packets: errors: dropped: overruns: carrier:

          collisions: txqueuelen:

          RX bytes: (0.0 B)  TX bytes: (0.0 B)

          Interrupt:

eth0      Link encap:Ethernet  HWaddr :0A::::

          inet addr:192.168.0.120  Bcast:192.168.0.255  Mask:255.255.255.0

          UP BROADCAST RUNNING MULTICAST  MTU:  Metric:

          RX packets: errors: dropped: overruns: frame:

          TX packets: errors: dropped: overruns: carrier:

          collisions: txqueuelen:

          RX bytes: (465.3 KiB)  TX bytes: (18.1 KiB)

          Interrupt: Base address:0xb000

lo        Link encap:Local Loopback

          LOOPBACK  MTU:  Metric:

          RX packets: errors: dropped: overruns: frame:

          TX packets: errors: dropped: overruns: carrier:

          collisions: txqueuelen:

          RX bytes: (0.0 B)  TX bytes: (0.0 B)

设置can0的波特率，这里设置的是100k, ip程序一般需要自己编译生成，参见2
#./ip link set can0 up type can bitrate 100000
显示can0状态信息
#./ip -d -s link show can0

Z-turn# ./ip link set can0 type can bitrate

xilinx_can e0008000.can can0: bitrate error 0.0%

Z-turn#./ip link set can0 up

Z-turn#./ip -d -s link show can0

: can0: <NOARP,UP,LOWER_UP,ECHO> mtu  qdisc pfifo_fast state UNKNOWN mode DEFAULT group default qlen

    link/can  promiscuity

    can state ERROR-ACTIVE (berr-counter tx  rx ) restart-ms

          bitrate  sample-point 0.750

          tq  prop-seg  phase-seg1  phase-seg2  sjw

          xilinx_can: tseg1 .. tseg2 .. sjw .. brp .. brp-inc

          clock

          re-started bus-errors arbit-lost error-warn error-pass bus-off

                                                                     numtxqueues  numrxqueues

    RX: bytes  packets  errors  dropped overrun mcast

    TX: bytes  packets  errors  dropped carrier collsns

5.下面程序为收发测试，也可参见参考文献3

/*****************************************************************************

 * Copyright (c) 2014-2017 MYIR Tech Ltd.

 *        File: can-test.c

 *        Date: 2014/11/3

 *      Author: Kevin Su

 * Description: A demo program to show how to transmit/receive data with

 *              socket can interface on CAN bus.

 *                Please note that, this demo needs two boards to run as

 *                transmitter and receiver.

 *                Before run "can-test", we need to config the bitrate with

 *              "ip" command:

 *              # ip link set can0 up type can bitrate 100000

 */

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/ioctl.h>

#include <net/if.h>

#include <linux/can.h>

#include <linux/can/raw.h>

#define DEBUG    1

#define ERR_MSG(fmt, args...)    fprintf(stderr, fmt, ##args)

#ifdef DEBUG

    #define DBG_MSG(fmt, args...)    fprintf(stdout, fmt, ##args)

#else

    #define DBG_MSG(fmt, args...)

#endif

#ifndef PF_CAN

    #define PF_CAN 29

#endif

#ifndef AF_CAN

    #define AF_CAN PF_CAN

#endif

int main(int argc, char *argv[])

{

    int fd, ret, flag, len;

    char senddata[] = "test";

    struct sockaddr_can addr;

    struct ifreq ifr;

    struct can_frame frame;

    socklen_t socket_len = sizeof(struct sockaddr_can);

    /* Create a socket with PF_CAN family, SOCK_RAW and CAN_RAW protocol */

    fd = socket(PF_CAN, SOCK_RAW, CAN_RAW);

    if (fd < ) {

        ERR_MSG("Open socket failed!\n");

        return fd;

    }

    /* Use can0 */

    strcpy((char *)(ifr.ifr_name), "can0");

    /* Get information */

    ret = ioctl(fd, SIOCGIFINDEX, &ifr);

    if (ret != ) {

        ERR_MSG("SIOCGIFINDEX failed! ret:%d\n", ret);

        close(fd);

        return ret;

    }

    DBG_MSG("can0 can_ifindex = %x\n",ifr.ifr_ifindex);

    /* Disable loopback */

    flag = ;

    ret = setsockopt(fd, SOL_CAN_RAW, CAN_RAW_LOOPBACK, &flag, sizeof(flag));

    if (ret != ) {

        ERR_MSG("Set loopback disable failed! ret:%d\n", ret);

        close(fd);

        return ret;

    }

    DBG_MSG("Set can0 loopback disable\n");

    /* Disable receiving own message */

    flag = ;

    ret = setsockopt(fd, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS,

               &flag, sizeof(flag));

    if (ret != ) {

        ERR_MSG("Disable receiving own message failed! ret:%d\n", ret);

        close(fd);

        return ret;

    }

    DBG_MSG("Disable receiving own message\n");

    /* Use AF_CAN protocol family */

    addr.can_family = AF_CAN;

    addr.can_ifindex = ifr.ifr_ifindex;

    /* Binding socket */

    ret = bind(fd, (struct sockaddr*)&addr, sizeof(addr));

    if (ret != ) {

        ERR_MSG("Bind socket failed! ret:%d\n", ret);

        close(fd);

        return ret;

    }

    DBG_MSG("Bind can0 socket\n");

    frame.can_id = 0x123;

    len = strlen(senddata);

    while () {

        strncpy((char *)frame.data, senddata, len);

        frame.can_dlc = len;

        ret = sendto(fd, &frame, sizeof(struct can_frame), , (struct sockaddr*)&addr, sizeof(addr));

        if (ret > ) {

            DBG_MSG("Send success: [%s], ret=%d\n", senddata, ret);

            ret = recvfrom(fd, &frame, sizeof(struct can_frame), , (struct sockaddr *)&addr, &socket_len);

            if (ret > ) {

                DBG_MSG("Recv message: [%s], ret=%d\n", frame.data, ret);

            }

        }

        usleep();

    }

    return ;

}

超时设置(参考文献4)：

struct timeval timeout = {,}; //1.0s

 //设置发送超时

setsockopt(socket，SOL_SOCKET,SO_SNDTIMEO，(char *)&timeout,sizeof(struct timeval));

//设置接收超时

setsockopt(socket，SOL_SOCKET,SO_RCVTIMEO，(char *)&timeout,sizeof(struct timeval));

对于offline节点处理：

如果该控制器没有连接到can网络上，调用send会返回成功，但只是发送至kernel的缓冲区，并非发送至can网络。kernel会一直尝试重发，即使关闭socket或结束进程都不会取消重发操作，此时如果将控制器连接到can网络上则会一次性将缓冲区内所有内容发出，有时这并非所要结果。如果想要清空发送和接收缓冲区，只能重启can接口

ifconfig can0 down

ifconfig can0 up

在程序中可使用system调用。

有两点注意就是：

1）recv ()的第四个参数需为MSG_WAITALL，在阻塞模式下不等到指定数目的数据不会返回，除非超时时间到。

2）即使等待超时时间值未到，但对方已经关闭了socket，则此时recv()会立即返回，并收到多少数据返回多少数据。

参考文献：

1.http://xilinx.eetrend.com/blog/12062

2.http://www.cnblogs.com/hujianhua/p/8446291.html

3.https://wenku.baidu.com/view/65baea51bb68a98271fefaa7.html

4.https://blog.csdn.net/newger/article/details/2459113

巴特西

zynq+linux+ramdisk can调试

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