TDA4VM: 设备号无法固定

davied zhang

Part Number: TDA4VM

您好

我们在使用TDA4VM评估板时，发现CAN设备号是变动的，尝试使用别名的方式，将CAN设备号固定下来，dts文件如下：

/ {
	chosen {
		stdout-path = "serial2:115200n8";
		bootargs = "console=ttyS2,115200n8 earlycon=ns16550a,mmio32,0x02800000";
	};
	
    aliasis{
        can0 = &mcu_mcan0;
        can1 = &mcu_mcan1;
        can2 = &main_mcan0;
        can3 = &main_mcan2;
    };

但是还是出现设备号变动的情况，比如我们使用的是mcu_mcan0，发现真实设备号can3，并不是can0。查看/sys下aliasis下can0~3内容，传递参数也是对的

cat /sys/firmware/devicetree/base/aliasis/can0
/bus@100000/bus@28380000/can@40528000

cat /sys/firmware/devicetree/base/aliasis/can1
/bus@100000/bus@28380000/can@40568000

cat /sys/firmware/devicetree/base/aliasis/can2
/bus@100000/can@2701000

cat /sys/firmware/devicetree/base/aliasis/can3 
/bus@100000/can@2721000

想了解下，这个问题如何解决？或者是否有其他方式来固定can设备号

2 年多前

0 Cherry Zhou 2 年多前

TI__Guru* 81380 points

您好，您的问题我们需要升级到英文论坛看下，链接如下。由于国外假期，给到答复的时间可能会有所延迟，敬请谅解：

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1244130/tda4vm-device-number-cannot-be-fixed

0 davied zhang 2 年多前回复 Cherry Zhou

Prodigy 200 points

好的，发现之前aliases拼写有问题，重新尝试时换成非自动枚举的设备名，如下所示：

        aliases{
               mcu_can0 = &mcu_mcan0;
               mcu_can1 = &mcu_mcan1;
               main_can0 = &main_mcan0;
               main_can2 = &main_mcan2;
        };

然后发现，CAN设备还是使用的自动枚举的名字，不是别名。

can0: flags=128<NOARP>  mtu 16  metric 1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 23  

can1: flags=128<NOARP>  mtu 16  metric 1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 25  

can2: flags=128<NOARP>  mtu 16  metric 1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 55  

can3: flags=128<NOARP>  mtu 16  metric 1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 57

从现象来看，貌似是别名未生效。但是在系统信息中，别名传递应该没问题，确实有新增的别名信息，不知道为什么没有生效

root@j7-evm:~# ls /sys/firmware/devicetree/base/aliases/
ethernet0  main_can2  mcu_can1	mmc1  serial0  serial10  serial2  serial4  serial6  serial8
main_can0  mcu_can0   mmc0	name  serial1  serial11  serial3  serial5  serial7  serial9

0 Cherry Zhou 2 年多前回复 davied zhang

TI__Guru* 81380 points

您好，

您检查下在/sys/class/net下的实例？是否是按照别名中所述的顺序？

0 davied zhang 2 年多前回复 Cherry Zhou

Prodigy 200 points

net下还是can0 can1 can2 can3这些自动自动识别出的实例。

root@j7-evm:~# ls /sys/class/net/
can0  can1  can2  can3	docker0  eth0  eth1  eth2  lo

lrwxrwxrwx 1 root root 0 Mar  3 23:11 can0 -> ../../devices/platform/bus@100000/bus@100000:bus@28380000/40568000.can/net/can0
lrwxrwxrwx 1 root root 0 Mar  3 23:11 can1 -> ../../devices/platform/bus@100000/bus@100000:bus@28380000/40528000.can/net/can1
lrwxrwxrwx 1 root root 0 Mar  3 23:11 can2 -> ../../devices/platform/bus@100000/2721000.can/net/can2
lrwxrwxrwx 1 root root 0 Mar  3 23:11 can3 -> ../../devices/platform/bus@100000/2701000.can/net/can3