DP83826E 自协商成功后链路丢失

2023-04-29 16:03:17

1. 前言

使用DP83826E与Linux SDK ti-processor-sdk-linux-rt-am335x-evm-07.03.00.005 当用一根直线将板子连接到我的笔记本电脑上时我看到连接在上升和下降添加了一些调试信息来打印PHYSTS寄存器

显然，该设备正在尝试从10Base-T半双工和100Base-T全双工开始的每一种操作模式即使当PHYSTS寄存器检测到信号和解码器锁(0x4F15) 链路将在状态寄存器的下一次轮询时下降我应该配置哪些寄存器以使PHY工作在交叉电缆模式? (如果我把它连接到一个开关上，它就能工作了!)

[ 54.483271] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x786D [ 54.483518] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x4115 [ 54.483801] 000: prueth pruss_eth eth1: Link is Up – 100Mbps/Full – flow control off [ 54.483822] 000: TI DP83826NC 4a332400.mdio:01: PHY state change NOLINK -> RUNNING [ 54.483861] 000: IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready [ 55.523375] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 55.523621] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x0912 [ 55.523661] 000: prueth pruss_eth eth1: Link is Down [ 55.523672] 000: TI DP83826NC 4a332400.mdio:01: PHY state change RUNNING -> NOLINK [ 56.563312] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x786D [ 56.563563] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x0F15 [ 56.563845] 000: prueth pruss_eth eth1: Link is Up – 100Mbps/Full – flow control off [ 56.563866] 000: TI DP83826NC 4a332400.mdio:01: PHY state change NOLINK -> RUNNING [ 57.603273] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 57.603517] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x4912 [ 57.603560] 000: prueth pruss_eth eth1: Link is Down [ 57.603570] 000: TI DP83826NC 4a332400.mdio:01: PHY state change RUNNING -> NOLINK [ 58.643276] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 58.643523] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x0902 [ 59.683270] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x786D [ 59.683518] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x4F15 [ 59.683799] 000: prueth pruss_eth eth1: Link is Up – 100Mbps/Full – flow control off [ 59.683821] 000: TI DP83826NC 4a332400.mdio:01: PHY state change NOLINK -> RUNNING [ 60.723388] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 60.723634] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x0912 [ 60.723674] 000: prueth pruss_eth eth1: Link is Down [ 60.723686] 000: TI DP83826NC 4a332400.mdio:01: PHY state change RUNNING -> NOLINK [ 61.763269] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x786D [ 61.763514] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x4F15 [ 61.763796] 000: prueth pruss_eth eth1: Link is Up – 100Mbps/Full – flow control off [ 61.763818] 000: TI DP83826NC 4a332400.mdio:01: PHY state change NOLINK -> RUNNING [ 62.803317] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 62.803585] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x4912 [ 62.803626] 000: prueth pruss_eth eth1: Link is Down [ 62.803637] 000: TI DP83826NC 4a332400.mdio:01: PHY state change RUNNING -> NOLINK [ 63.843269] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 63.843515] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x0902 [ 64.883273] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 64.883520] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x0912

当连接到以太网交换机时，我添加寄存器值，直到我断开电缆:

[ 61.683376] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x786D [ 61.683623] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x5115 [ 61.683908] 000: prueth pruss_eth eth1: Link is Up – 100Mbps/Full – flow control off [ 61.683930] 000: TI DP83826NC 4a332400.mdio:01: PHY state change NOLINK -> RUNNING [ 61.683971] 000: IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready [ 62.723894] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x786D [ 62.724149] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x5715 [ 63.763383] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x786D [ 63.763628] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x5715 ……………….. [ 76.243409] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 76.243678] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x5912 [ 76.243722] 000: prueth pruss_eth eth1: Link is Down [ 76.243732] 000: TI DP83826NC 4a332400.mdio:01: PHY state change RUNNING -> NOLINK [ 77.283380] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x7849 [ 77.283629] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x5902 2. 原理图

DP83826E 自协商成功后链路丢失

3. 问题梳理

当强制MDI/MDIX分辨率的速度时，问题是否仍然存在? 电缆长度是多少? 是否启用了快速链接特性(寄存器0xB)? 如果是，当禁用快速链路删除时是否会发生链路删除?

如果我强制速度到100 Mbps和全双工(寄存器0x0在0x2100)，我也能得到连接，当电缆连接到我的电脑。如果在基本模式下支持直/交叉电缆检测，我们也在徘徊。

是的，该设备应该完全支持auto-MDIX特性这里是注册状态与连接，但没有任何传输所以快速链接下降是不启用的电缆长2米

[ 173.927654] 000: TI DP83826NC 4a332400.mdio:01: BMCR [0x00] = 0x2100 [ 173.927921] 000: TI DP83826NC 4a332400.mdio:01: CR1 [0x09] = 0x0000 [ 173.928166] 000: TI DP83826NC 4a332400.mdio:01: CR2 [0x0A] = 0x0100 [ 173.928410] 000: TI DP83826NC 4a332400.mdio:01: CR3 [0x0B] = 0x0000 [ 173.928655] 000: TI DP83826NC 4a332400.mdio:01: BMSR [0x01] = 0x784D [ 173.928898] 000: TI DP83826NC 4a332400.mdio:01: PHYSTS [0x10] = 0x0605 4. RJ45连接器

还添加了部分原理图的RJ45连接器。

DP83826E 自协商成功后链路丢失1