以太网PHY寄存器分析以太网PHY驱动软件配置-电子发烧友网

我们对g_ethercat_ssc_port0_ext_cfg这个全局变量深入追踪，其成员变量 g_ether_PHY0，正好是一个PHY实例的详细描述体。

/* Instance structure to use this module. */
const ether_PHY_instance_t g_ether_PHY0 =
{
  .p_ctrl    = &g_ether_PHY0_ctrl,
  .p_cfg     = &g_ether_PHY0_cfg,
  .p_api     = &g_ether_PHY_on_ether_PHY
};

其中g_ether_PHY0_cfg是pyh实例的配置结构体：

const ether_PHY_cfg_t g_ether_PHY0_cfg =
{


  .channel          = 0,
  .PHY_lsi_address      = 0,
  .PHY_reset_wait_time    = 0x00020000,
  .mii_bit_access_wait_time = 0,             // Unused
  .flow_control       = ETHER_PHY_FLOW_CONTROL_DISABLE,
  .mii_type         = (ether_PHY_mii_type_t) 0, // Unused
  .p_context         = NULL,
  .p_extend         = &g_ether_PHY0_extend
};

这里又通过p_extend 做了扩展配置（其实可以合并在一起）如下所示：

const ether_PHY_extend_cfg_t g_ether_PHY0_extend =
{
  .port_type     = ETHER_PHY_PORT_TYPE_ETHER_CAT,
  .PHY_chip      = (ether_PHY_chip_t) ETHER_PHY_CHIP_VSC8541,
  .mdio_type     = ETHER_PHY_MDIO_GMAC,


  .bps        = ETHER_PHY_SPEED_100,
  .duplex       = ETHER_PHY_DUPLEX_FULL,
  .auto_negotiation  = ETHER_PHY_AUTO_NEGOTIATION_ON,


  .PHY_reset_pin   = BSP_IO_PORT_20_PIN_7,
  .PHY_reset_time   = 15000,


  .p_selector_instance = (ether_selector_instance_t *)&g_ether_selector0,
};

可以看到上面的扩展配置当中，PHY的具体硬件型号都已经列出，如PHY_chip = (ether_PHY_chip_t) ETHER_PHY_CHIP_;

可以看到在示例代码当中已经支持的PHY如下所示：

/** Identify PHY-LSI */
typedef enum e_ether_PHY_chip
{
  ETHER_PHY_CHIP_VSC8541 = (1 << 0), ///< VSC8541
    ETHER_PHY_CHIP_KSZ9131 = (1 << 1), ///< KSZ9131
    ETHER_PHY_CHIP_KSZ9031 = (1 << 2), ///< KSZ9031
    ETHER_PHY_CHIP_KSZ8081 = (1 << 3), ///< KSZ8081
    ETHER_PHY_CHIP_KSZ8041 = (1 << 4)  ///< KSZ8041
} ether_PHY_chip_t;

这里具体看一下 g_ether_selector0 这个 ether_selector_instance_t 类型的全局指针，指向 selector driver实例的成员变量：

typedef struct st_ether_selector_instance
{
  ether_selector_ctrl_t   * p_ctrl; ///< Pointer to the control structure for this instance
    ether_selector_cfg_t const * p_cfg;  ///< Pointer to the configuration structure for this instance
    ether_selector_api_t const * p_api;  ///< Pointer to the API structure for this instance
} ether_selector_instance_t;

这又是一个类似的结构体，通过三个指针来分别指向结构本身，selector的具体配置，和配置selector过程中所需要用的的成员方法api.

看一下selector的具体配置信息：

typedef struct st_ether_selector_cfg
{
  uint8_t port;               ///< Port number
    ether_selector_PHYlink_polarity_t PHYlink; ///< PHY link signal polarity


    ether_selector_interface_t interface;      ///< Converter mode
    ether_selector_speed_t     speed;          ///< Converter Speed
    ether_selector_duplex_t    duplex;         ///< Converter Duplex
    ether_selector_ref_clock_t ref_clock;      ///< Converter REF_CLK
    void const               * p_extend;       ///< Placeholder for user extension.
} ether_selector_cfg_t;

可以看到selector 对应的端口号，PHY连接信号对应的极性，接口模式，速率，全双工，以及外部时钟输入。再看一下配置selector的过程中所需要用到的API函数：

const ether_selector_api_t g_ether_selector_on_ether_selector =
{
  .open     = R_ETHER_SELECTOR_Open,
  .converterSet = R_ETHER_SELECTOR_ConverterSet,
  .close    = R_ETHER_SELECTOR_Close,
  .versionGet  = R_ETHER_SELECTOR_VersionGet
};

其最主要的成员方法就是R_ETHER_SELECTOR_Open做了些什么：

先初始化ETHER_SELECTOR

 /* One time initialization for all ETHER_SELECTOR instances. */
  r_ether_selector_state_initialize();


  /* Unlock write access protection for Ethernet subsystem registers */
  r_ether_selector_reg_protection_disable(p_reg_ethss);
  
  /* Set the function of Ethernet ports. */
  sw_mode = ETHER_SELECTOR_CFG_MODE;
  p_reg_ethss->MODCTRL_b.SW_MODE = sw_mode & ETHER_SELECTOR_MODCTRL_BIT_SWMODE_MASK;
  
  /* Set the MAC of all port for half-duplex. */
  p_reg_ethss->SWDUPC_b.PHY_DUPLEX = 0;
  
  /* Set all Ethernet switch port to select not use 10Mbps. */
  p_reg_ethss->SWCTRL_b.SET10 = 0;

根据端口号来选择对应控制寄存器

/* Set RGMII/RMII Converter configuration */
  switch (port)
  {
    case 0:
    {
      p_reg_convctrl = (uint32_t *) &p_reg_ethss->CONVCTRL[0];
      break;
    }


    case 1:
    {
      p_reg_convctrl = (uint32_t *) &p_reg_ethss->CONVCTRL[1];
      break;
    }


    case 2:
    default:
    {
      p_reg_convctrl = (uint32_t *) &p_reg_ethss->CONVCTRL[2];
      break;
    }
  }

根据指向selector的配置信息：

const ether_selector_cfg_t g_ether_selector0_cfg =
{
  .port           = 0,
  .PHYlink          = ETHER_SELECTOR_PHYLINK_POLARITY_LOW,
  .interface         = ETHER_SELECTOR_INTERFACE_RGMII,
  .speed           = ETHER_SELECTOR_SPEED_100MBPS,
  .duplex          = ETHER_SELECTOR_DUPLEX_FULL,
  .ref_clock         = ETHER_SELECTOR_REF_CLOCK_INPUT,
  .p_extend         = NULL,
};

来对CONVCTRL[port_number]寄存器做相应的配置

这里结合RZ/T2M的用户手册，很容易理解其中的意思：

结合代码来看，总体ETHER_SELECTOR 的驱动的配置流程图台下所示：

在对ETHER_SELECTOR驱动做完配置后，下面具体看一下对ETHER_PHY_CHIP这个PHY，代码具体做了哪些操作：

首先是做初始化：

oid ether_PHY_targets_initialize_vsc8541 (ether_PHY_instance_ctrl_t * p_instance_ctrl)
{
  /* Vendor Specific PHY Registers */
 #define ETHER_PHY_REG_LED_MODE_SELECT         (0x1D)
 #define ETHER_PHY_REG_LED_BEHAVIOR          (0x1E)
 #define ETHER_PHY_REG_EXTEND_GPIO_PAGE        (0x1F)
...

这个初始化函数，并没有对IEEE 标准规定的16个寄存器做读写操作，只对厂商自定义的寄存器做了配置。初始化完成之后，对是否打开自动协商的功能对PHY进行了读写：