[linux kernel] 内核下ksz9031驱动调试踩过的坑

系统版本：Ubuntu18.04-64

编译器版本：gcc version 7.4.0 (Ubuntu/Linaro 7.4.0-1ubuntu1~18.04.1)

uboot版本：2018.07 -linux4sam_6.0

板子型号：at91sama5d3x-xplained

MCU型号：sama5d36

内核中调试驱动，和uboot中会有些区别，因为内核启动过程是顺序启动的，硬件上电后，外部的器件要快速做好准备工作，内核代码初始化到这个器件如果器件没有完成上电复位，很可能会驱动失败，需要硬件和软件时序同步，这是非常重要的一点。

【Datasheet】PHY KSZ9031千兆网络芯片解读

[Linux 底层]U-boot ksz9031网络驱动调试

一、PHY在内核配置中需要使能对应的芯片厂商驱动Micrel公司PHY；

make menuconfig

Device Drivers  --->

     [*] Network device support  ---> 

        [*]   Ethernet driver support  --->

        -*-   MDIO bus device drivers  ---- //MDIO控制器读取PHY寄存器

        -*-   PHY Device support and infrastructure  --->

            <*>   Micrel PHYs       //Micrel公司的ksz9031和ksz8081

二、修改设备树文件，硬件配置语言，所有的硬件相关信息都需要从设备树中获取。这是新内核的特性。

//arch/arm/boot/dts/at91-sama5d3_xplaint.dts

            macb0: ethernet@f0028000 {

                phy-mode = "rgmii";

                #address-cells = <1>;

                #size-cells = <0>;

                status = "okay";

                ethernet-phy@0 {

                    reg = <0x0>;

                };

            };

三、把编译出的zImage烧录进板子，查看打印信息

CAN device driver interface

at91_can f000c000.can: device registered (reg_base=(ptrval), irq=42)

libphy: MACB_mii_bus: probed

Generic PHY f0028000.ethernet-ffffffff:01: attached PHY driver [Generic PHY] (mii_bus:phy_addr=f0028000.ethernet-ffffffff:01, irq=POLL)

macb f0028000.ethernet eth0: Cadence GEM rev 0x00020119 at 0xf0028000 irq 43 (ee:ab:c1:d2:e6:c6)

macb f802c000.ethernet: invalid hw address, using random

libphy: MACB_mii_bus: probed

Micrel KSZ8081 or KSZ8091 f802c000.ethernet-ffffffff:01: attached PHY driver [Micrel KSZ8081 or KSZ8091] (mii_bus:phy_addr=f802c000.ethernet-ffffffff:01, irq=49)

macb f802c000.ethernet eth1: Cadence MACB rev 0x0001010c at 0xf802c000 irq 44 (36:d7:c3:e6:2a:c7)

ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver5d36

其中，Generic PHY f0028000.ethernet-ffffffff:01；获取到得ID为全FF，硬件地址01；这里获取芯片的ID错误了，可能出错的点有MDIO配置错误，或者设备树配置错误；

不用太担心，可以根据打印的信息，查找对应的代码，添加上一些标识在里面；比如：macb f0028000.ethernet: macb_probe phy_interface=2.接口方式，可以搜索出对应的代码，然后添加Jack标识，再次烧录，即可打印出添加的信息；

linux-at91-linux-4.19-at91driversnetethernetcadencemacb_main.c

static int macb_probe(struct platform_device *pdev)函数添加打印，

使用dev_info，用调试串口把信息打印出来，这是调试的必备手段；

图片

我们下面把PHY的接口方式，PHY ID都打印出来，看看和设备树是否能够对应上；

2、内核的网卡驱动找不到对应的PHY驱动

内核打印信息

macb f0028000.ethernet: Jack macb_probe phy_interface=2.

macb f0028000.ethernet: macb_mii_init name=f0028000.ethernet,id=ffffffff

libphy: MACB_mii_bus: probed

Generic PHY f0028000.ethernet-ffffffff:07: attached PHY driver [Generic PHY] (mii_bus:phy_addr=f0028000.ethernet-ffffffff:07, irq=POLL)

macb f0028000.ethernet eth0: Cadence GEM rev 0x00020119 at 0xf0028000 irq 46 (ee:ab:c1:d2:e6:c6)

macb f802c000.ethernet: invalid hw address, using random

macb f802c000.ethernet: Jack macb_probe phy_interface=7.

macb f802c000.ethernet: macb_mii_init name=f802c000.ethernet,id=ffffffff

libphy: MACB_mii_bus: probed

Generic PHY f802c000.ethernet-ffffffff:01: attached PHY driver [Generic PHY] (mii_bus:phy_addr=f802c000.ethernet-ffffffff:01, irq=POLL)

macb f802c000.ethernet eth1: Cadence MACB rev 0x0001010c at 0xf802c000 irq 47 (06:50:95:f8:63:dc)

全是id=ffffffff，怀疑是MDIO有问题

这里只匹配了Ksz8081的驱动；

phy_interface = 2;代表是MII接口

图片

四、继续添加打印信息，PHY外部最多可挂载32个PHY设备，内核是如何做识别的呢，使用for循环扫描的，如果读取到ID不为全FF，则认为是有效的设备，会对该设备进行驱动配对；再往前添加一些打印信息，看看扫描的过程是如何的；

libphy: mdiobus_scan i= 0

libphy: get_phy_device addr=0,get_phy_id=-1,

libphy: mdiobus_scan i= 1

libphy: get_phy_device addr=1,get_phy_id=-1,

libphy: mdiobus_scan i= 2

libphy: get_phy_device addr=2,get_phy_id=-1,

libphy: mdiobus_scan i= 3

libphy: get_phy_device addr=3,get_phy_id=-1,

libphy: mdiobus_scan i= 4

libphy: get_phy_device addr=4,get_phy_id=-1,

libphy: mdiobus_scan i= 5

libphy: get_phy_device addr=5,get_phy_id=-1,

libphy: mdiobus_scan i= 6

libphy: get_phy_device addr=6,get_phy_id=-1,

libphy: mdiobus_scan i= 7

libphy: get_phy_device addr=7,get_phy_id=-1,

libphy: mdiobus_scan i= 8

libphy: get_phy_device addr=8,get_phy_id=-1,

libphy: mdiobus_scan i= 9

libphy: get_phy_device addr=9,get_phy_id=-1,

libphy: mdiobus_scan i= 10

libphy: get_phy_device addr=10,get_phy_id=-1,

libphy: mdiobus_scan i= 11

libphy: get_phy_device addr=11,get_phy_id=-1,

libphy: mdiobus_scan i= 12

libphy: get_phy_device addr=12,get_phy_id=-1,

libphy: mdiobus_scan i= 13

libphy: get_phy_device addr=13,get_phy_id=-1,

libphy: mdiobus_scan i= 14

libphy: get_phy_device addr=14,get_phy_id=-1,

libphy: mdiobus_scan i= 15

libphy: get_phy_device addr=15,get_phy_id=-1,

libphy: mdiobus_scan i= 16

libphy: get_phy_device addr=16,get_phy_id=-1,

libphy: mdiobus_scan i= 17

libphy: get_phy_device addr=17,get_phy_id=-1,

libphy: mdiobus_scan i= 18

libphy: get_phy_device addr=18,get_phy_id=-1,

libphy: mdiobus_scan i= 19

libphy: get_phy_device addr=19,get_phy_id=-1,

libphy: mdiobus_scan i= 20

libphy: get_phy_device addr=20,get_phy_id=-1,

libphy: mdiobus_scan i= 21

libphy: get_phy_device addr=21,get_phy_id=-1,

libphy: mdiobus_scan i= 22

libphy: get_phy_device addr=22,get_phy_id=-1,

libphy: mdiobus_scan i= 23

libphy: get_phy_device addr=23,get_phy_id=-1,

libphy: mdiobus_scan i= 24

libphy: get_phy_device addr=24,get_phy_id=-1,

libphy: mdiobus_scan i= 25

libphy: get_phy_device addr=25,get_phy_id=-1,

libphy: mdiobus_scan i= 26

libphy: get_phy_device addr=26,get_phy_id=-1,

libphy: mdiobus_scan i= 27

libphy: get_phy_device addr=27,get_phy_id=-1,

libphy: mdiobus_scan i= 28

libphy: get_phy_device addr=28,get_phy_id=-1,

libphy: mdiobus_scan i= 29

libphy: get_phy_device addr=29,get_phy_id=-1,

libphy: mdiobus_scan i= 30

libphy: get_phy_device addr=30,get_phy_id=-1,

libphy: mdiobus_scan i= 31

libphy: get_phy_device addr=31,get_phy_id=-1,

libphy: Fixed MDIO Bus: probed

CAN device driver interface

at91_can f000c000.can: device registered (reg_base=(ptrval), irq=45)

macb f0028000.ethernet: Jack macb_probe phy_interface=2.

macb f0028000.ethernet: Jack macb_is_gem gem_ethtool_ops

macb f0028000.ethernet: Jack macb_mdc_clk_div =0x100000

macb f0028000.ethernet: Jack macb_dbw =0x300000,bp->phy_interface=2

libphy: MACB_mii_bus: probed

libphy: get_phy_device addr=0,get_phy_id=25278624,

Generic PHY f0028000.ethernet-ffffffff:00: attached PHY driver [Generic PHY] (mii_bus:phy_addr=f0028000.ethernet-ffffffff:00, irq=POLL)

macb f0028000.ethernet eth0: Cadence GEM rev 0x00020119 at 0xf0028000 irq 46 (ee:ab:c1:d2:e6:c6)

macb f802c000.ethernet: invalid hw address, using random

macb f802c000.ethernet: Jack macb_probe phy_interface=7.

macb f802c000.ethernet: Jack macb_is_gem macb_ethtool_ops

macb f802c000.ethernet: Jack macb_mdc_clk_div =0xc00

macb f802c000.ethernet: Jack macb_dbw =0xc00,bp->phy_interface=7

libphy: MACB_mii_bus: probed

libphy: get_phy_device addr=0,get_phy_id=2233697,

Micrel KSZ8081 or KSZ8091 f802c000.ethernet-ffffffff:00: attached PHY driver [Micrel KSZ8081 or KSZ8091] (mii_bus:phy_addr=f802c000.ethernet-ffffffff:00, irq=POLL)

macb f802c000.ethernet eth1: Cadence MACB rev 0x0001010c at 0xf802c000 irq 44 (86:82:71:07:ba:d2)

libphy: MACB_mii_bus: probed

libphy: get_phy_device addr=0,get_phy_id=25278624；其中在地址0上面读取到了PHY的ID，转化为16进制：0xF113644,和手册上面无法对应；但是为什么就是驱动识别不了呢？

更改设备树的PHY芯片地址；

//arch/arm/boot/dts/at91-sama5d3_xplaint.dts

GMAC外部PHY的地址为7，dts中配置的地址为0，地址不匹配，读取不了数据；

            macb0: ethernet@f0028000 {

                phy-mode = "rgmii";

                #address-cells = <1>;

                #size-cells = <0>;

                status = "okay";

                ethernet-phy@0 {

                    reg = <0x0>;

                };

            };

    改为：

            macb0: ethernet@f0028000 {

                phy-mode = "mii";

                #address-cells = <1>;

                #size-cells = <0>;

                status = "okay";

                ethernet-phy@7{

                    reg = <0x7>;

                };

            };

再次下载尝试，打印识别芯片正常，驱动可以正确匹配；

libphy: MACB_mii_bus: probed

libphy: get_phy_device addr=3,get_phy_id=-1,

mdio_bus f0028000.ethernet-ffffffff: MDIO device at address 3 is missing.

libphy: get_phy_device addr=0,get_phy_id=-1,

libphy: get_phy_device addr=1,get_phy_id=-1,

libphy: get_phy_device addr=2,get_phy_id=-1,

libphy: get_phy_device addr=3,get_phy_id=-1,

libphy: get_phy_device addr=4,get_phy_id=-1,

libphy: get_phy_device addr=5,get_phy_id=-1,

libphy: get_phy_device addr=6,get_phy_id=-1,

libphy: get_phy_device addr=7,get_phy_id=2233890,

libphy: get_phy_device addr=8,get_phy_id=-1,

libphy: get_phy_device addr=9,get_phy_id=-1,

libphy: get_phy_device addr=10,get_phy_id=-1,

libphy: get_phy_device addr=11,get_phy_id=-1,

libphy: get_phy_device addr=12,get_phy_id=-1,

libphy: get_phy_device addr=13,get_phy_id=-1,

libphy: get_phy_device addr=14,get_phy_id=-1,

libphy: get_phy_device addr=15,get_phy_id=-1,

libphy: get_phy_device addr=16,get_phy_id=-1,

libphy: get_phy_device addr=17,get_phy_id=-1,

libphy: get_phy_device addr=18,get_phy_id=-1,