1.CPSW驱动及设备的初始化;
(1)首先驱动注册cpsw_driver ,会自动进入cpsw_probe执行;
1 static struct platform_driver cpsw_driver = { 2 .driver = { 3 .name = "cpsw", 4 .owner = THIS_MODULE, 5 .pm = &cpsw_pm_ops, 6 }, 7 .probe = cpsw_probe, 8 .remove = __devexit_p(cpsw_remove), 9 };
(2)cpsw_probe初始化
进入cpsw_probe后,主要干活是:
- 创建 cpsw_priv *priv,入参pedv->dev.platform_data的参数,都赋值到priv里,后续主要使用的结构;
- 创建netdev结构,这个是网卡的默认数据结构,和上层协议栈通讯,注意注册都是用的name,后续作为匹配的,name应该来自入参;
- 初始化priv_sl2(网卡2),调用cpsw_init_slave_emac()函数,大部分是直接使用网卡1的priv数据直接复制过去;
- cpsw_netdev_ops内open,xmit等函数赋值到netdev的ndev->netdev_ops,协议栈使用会最终调用这些函数;
数据结构关系:
platform_device *pdev : .dev , 指向创建 netdev *ndev, 在netdev结构体后面定义一个 cpsw_priv *priv,
.dev.platform_data , 改名重定义指向到data ,
data: DMA DMA中断 ----> cpsw_priv *priv, 这个结构也是后面主要用的;
reg 寄存器信息
ALE 模块
MAC 配置
clk 时钟
下面对cpsw_probe函数主要部分说明一下:
static int __devinit cpsw_probe(struct platform_device *pdev)
{ struct cpsw_platform_data *data = pdev->dev.platform_data; struct net_device *ndev; struct cpsw_priv *priv; priv = netdev_priv(ndev); //在netdev后面,定义一个prio,用来保存详细的私有网卡数据; spin_lock_init(&priv->lock); priv->slaves = kzalloc(sizeof(struct cpsw_slave) * data->slaves, GFP_KERNEL); for (i = 0; i < data->slaves; i++) priv->slaves[i].slave_num = i; priv->slaves[0].ndev = ndev; //每个phy网卡对应的netdev结构绑定; priv->emac_port = 0; priv->regs = regs; //寄存器地址赋值过来; for_each_slave(priv, cpsw_slave_init, priv); priv->dma = cpdma_ctlr_create(&dma_params); //dma; priv->ale = cpsw_ale_create(&ale_params); //ale;
ndev->netdev_ops = &cpsw_netdev_ops; //主要的网卡发送,open函数都在这里赋值过去,协议栈最终使用的韩; /* register the network device */ SET_NETDEV_DEV(ndev, &pdev->dev);
ret = register_netdev(ndev); //注册netdev,给协议栈使用; ret = cpsw_init_slave_emac(pdev, priv);// 网卡2数据部分初始化; }
2.phy的扫描,设备注册,及读写函数初始化;
- Davinci_mdio.c,这个文件很多函数后面用到;
- genphy_driver 内的genphy_config_init,genphy_read_status,genphy_config_aneg等,后面在connect时候,及运行状态及都用的到;
- 当然,这些函数最底下,都是调用MDIO的读写函数接口;
(1)初始化MDIO
- 后面phy的读写都是调用这里赋值过来的函数,通过MDIO接口读写;
- mdiobus_register(data->bus);这句进去后,会先复位MDIO,扫描发现的PHY设备,及其ADDR地址,创建PHY DEV设备,给后续connect函数匹配PHY设备;
static int __devinit davinci_mdio_probe(struct platform_device *pdev) { data->bus->name = dev_name(dev); data->bus->read = davinci_mdio_read, data->bus->write = davinci_mdio_write, data->bus->reset = davinci_mdio_reset, data->bus->parent = dev; data->bus->priv = data; /* register the mii bus */ ret = mdiobus_register(data->bus); if (ret) goto bail_out; return 0; }
(2)注册扫描phy设备,发现phy,注册phy设备;
- 注意,这里会吧MDIO bus的ID(0)和phy的addr(0-31),合起来,写进phy dev的name,类似"0:13";
- 具体操作是在phy_device_create函数,语句是 dev_set_name(&dev->dev, PHY_ID_FMT, bus->id, addr);
- phy的创建,会设置速率,双工,状态机函数,name,ID等等;
int mdiobus_register(struct mii_bus *bus) { dev_set_name(&bus->dev, "%s", bus->id); err = device_register(&bus->dev); if (bus->reset) bus->reset(bus); //调用上面的davinci_mdio_reset复位MDIO,使能CLK,enable等 //复位函数中,读取MDIO的alive寄存器,反映当前发现的PHY,取反赋值到phy_mask,下一句创建scan使用; for (i = 0; i < PHY_MAX_ADDR; i++) { //对应MDIO,最多有0-31个地址的PHY,都扫描 if ((bus->phy_mask & (1 << i)) == 0) { struct phy_device *phydev; phydev = mdiobus_scan(bus, i);//把发现的phy,通过MDIO接口读取ID,判断有效,即创建phy dev设备; } } } }
3.phy的连接;
- 协议栈使用,会调用open函数,然后连接phy,配置phy的参数,启动状态机函数,配置自适应MAC的函数;
- 状态机就是下一步运行起来用的,会自协商,掉线重连等;
- 自适应MAC函数,在phy_connect 入参,带入,作为自协商速率后,配置CPU的MAC寄存器;
- 执行流程:netdev.netdev_ops.open -》 cpsw_ndo_open -》cpsw_slave_open -》phy_connect ,cpsw_set_phy_config
(1)cpsw_slave_open
主要是开启中断,配置mac地址,寻找用户配置的phy,运行phy状态机;
static void cpsw_slave_open(struct cpsw_slave *slave, struct cpsw_priv *priv) { soft_reset(name, &slave->sliver->soft_reset); cpsw_set_slave_mac(slave, priv);//mac地址设一下 slave->phy = phy_connect(priv->ndev, slave->data->phy_id, &cpsw_adjust_link, 0, slave->data->phy_if)//匹配用户配置的phy_name,在上一步MDIO创建的phy dev中寻找用户的phy,同时带入mac自适应函数 if (IS_ERR(slave->phy)) { msg(err, ifup, "phy %s not found on slave %d\n", slave->data->phy_id, slave->slave_num); slave->phy = NULL; } else { dev_info(priv->dev, "CPSW phy found : id is : 0x%x\n", slave->phy->phy_id); cpsw_set_phy_config(priv, slave->phy); //配置phy寄存器,速率等设置; phy_start(slave->phy); //状态:READY -> UP } }
(2)phy_connect
- 通过用户配置的phy name字段,到MDIO扫描到的phy dev列表寻找,找到后,返回phy dev设备;
- 调用 phy_connect_direct 把mac自适应函数赋给phy dev,开启phy dev创建时定义的状态机函数phy_state_machine,中断开启;
struct phy_device * phy_connect(struct net_device *dev, const char *bus_id, void (*handler)(struct net_device *), u32 flags, phy_interface_t interface) { /* Search the list of PHY devices on the mdio bus for the PHY with the requested name */ d = bus_find_device_by_name(&mdio_bus_type, NULL, bus_id); //用户配置的name,去匹配MDIO扫描创建的PHY的name,找到返回phy dev; phydev = to_phy_device(d); rc = phy_connect_direct(dev, phydev, handler, flags, interface);//配置MAC自适应函数,开启状态机 if (rc) return ERR_PTR(rc); return phydev; }
(3)读写phy的寄存器,配置phy速率;
- 退出上述函数后,返回外层,执行cpsw_set_phy_config,配置phy 的速率等;
- phy_start,把phy状态,ready,改为up;
4.phy运行
- phy_state_machine:状态机函数,up -> force / an -> run -> nolink -> changelink -> run;
- genphy_driver: phy的配置函数,基本都在里,phy_devices.c文件中;
- 实质:phy中断/phy状态机 ,run -》 changelink,状态机调用phy状态查询link及自协商,MAC的寄存器随之改变;
driver/net/phy/phy_devices.c //文件都是phy mdio 具体的驱动操作函数;
static struct phy_driver genphy_driver = { .config_init = genphy_config_init, //读取phy,查看支持的速率,双工等,赋值到phydev->support; .config_aneg = genphy_config_aneg, //重启phy的自协商,或者强制设置phy的速率 .read_status = genphy_read_status, //更新link状态,读取phy的速率,配置到phy结构,后面进状态机函数调用adjust自适应调整mac的速率; };
driver/net/phy/phy.c //主要是phy 状态机函数,phy中断,phy状态打印函数;
void phy_state_machine(struct work_struct *work) { if (phydev->adjust_state) phydev->adjust_state(phydev->attached_dev); //根据phy dev的速率更新,自适应调整mac的速率配置; switch(phydev->state) { case PHY_DOWN: case PHY_STARTING: case PHY_READY: case PHY_PENDING: break; case PHY_UP: //刚才连接完毕后,状态进入了 UP needs_aneg = 1; //设置该变量,最底下进 phy_start_aneg,调整phy进入 自协商或者强制 状态; break; case PHY_AN: err = phy_read_status(phydev); //更新link,读取phy状态reg的速率等,更新到dev的speed等; /* If the link is down, give up on negotiation for now */ if (!phydev->link) { phydev->state = PHY_NOLINK; netif_carrier_off(phydev->attached_dev); //告知内核子系统停止发包; phydev->adjust_link(phydev->attached_dev);//自适应调整MAC速率 break; } /* Check if negotiation is done. Break if there's an error */ err = phy_aneg_done(phydev); /* If AN is done, we're running */ if (err > 0) { phydev->state = PHY_RUNNING; netif_carrier_on(phydev->attached_dev); phydev->adjust_link(phydev->attached_dev); } else if (0 == phydev->link_timeout--) { int idx; needs_aneg = 1; /* If we have the magic_aneg bit, * we try again */ if (phydev->drv->flags & PHY_HAS_MAGICANEG) break; /* The timer expired, and we still don't have a setting, so we try forcing it until we find one that works, starting from the fastest speed,and working our way down */ idx = phy_find_valid(0, phydev->supported); phydev->speed = settings[idx].speed; phydev->duplex = settings[idx].duplex; phydev->autoneg = AUTONEG_DISABLE; } break; case PHY_NOLINK: err = phy_read_status(phydev); if (phydev->link) { phydev->state = PHY_RUNNING; netif_carrier_on(phydev->attached_dev); phydev->adjust_link(phydev->attached_dev); } break; case PHY_FORCING: err = genphy_update_link(phydev); //更新link状态; if (phydev->link) { phydev->state = PHY_RUNNING; //进入run状态; netif_carrier_on(phydev->attached_dev); //通知内核子系统,开启发包; } else { if (0 == phydev->link_timeout--) { phy_force_reduction(phydev); needs_aneg = 1; } } phydev->adjust_link(phydev->attached_dev); //调整MAC REG 速率; break; case PHY_RUNNING: /* Only register a CHANGE if we are polling */ if (PHY_POLL == phydev->irq) phydev->state = PHY_CHANGELINK; //phy产生中断,会进changlink状态,重新调整速率 break; case PHY_CHANGELINK: err = phy_read_status(phydev); //更新link,读取phy速率, if (phydev->link) { phydev->state = PHY_RUNNING; //进入run状态; netif_carrier_on(phydev->attached_dev); //告知内核子系统,协议栈,开启发包; } else { phydev->state = PHY_NOLINK; //进入nolink状态; netif_carrier_off(phydev->attached_dev); //停止发包; } phydev->adjust_link(phydev->attached_dev); //调整MAC速率寄存器配置; if (PHY_POLL != phydev->irq) err = phy_config_interrupt(phydev,PHY_INTERRUPT_ENABLED); break; case PHY_HALTED: if (phydev->link) { phydev->link = 0; netif_carrier_off(phydev->attached_dev); phydev->adjust_link(phydev->attached_dev); } break; case PHY_RESUMING: err = phy_clear_interrupt(phydev); err = phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);if (AUTONEG_ENABLE == phydev->autoneg)
{ err = phy_aneg_done(phydev); if (err > 0) { err = phy_read_status(phydev);if (phydev->link) { ..... } } ....break; } if (needs_aneg) err = phy_start_aneg(phydev); //自协商,进入an / force 状态; schedule_delayed_work(&phydev->state_queue, PHY_STATE_TIME * HZ); //状态机继续定时调度; }
5.phy_id的匹配
例如:phy_id = "0:19" 的匹配;
这个东西,别看少,贯穿了整个代码,得全局通读带起来才能看透;
注意:
- addr 对应的 phy的物理管脚连接,addr,范围是0-31;
- phy id 对应phy寄存器 PHYIDR1 PHYIDR2,类似0x20359081
- phy_id实际是phy dev的name字段,字符串形式,类似“0:19”,0是MDIO的总线ID,19是0x19,是addr;
- 得注意区分这三个,容易混淆;
(1) "0"
devices.c am33xx_cpsw_init - 》 pdev = omap_device_build("davinci_mdio", 0,...); //入参0配置MDIO设备pdv_id 为0;
(2) "0" "19" -> "0:19"
这里注册在MDIO总线上的phy_id的值:
Davinci_mdio.c davinci_mdio_probe - 》 snprintf(data->bus->id, MII_BUS_ID_SIZE, "%x", pdev->id);配置进 bus.id ,就是0; - 》 mdiobus_register - 》 mdiobus_scan - 》get_phy_device - 》 phy_device_create dev_set_name(&dev->dev, PHY_ID_FMT, bus->id, addr); 这里, bus->id为0, addr为19,id和addr合起来,即可得出,“0:19”
addr为扫描到的phy对应的地址,alive寄存器能看出来,具体值和实际的phy物理连接配置有关(phy手册有说明);
- 至此,软件扫描到的phy已经完成了phy_id的值,即phy的name字段;
- 接下来就等着用户配置的phy_id来匹配了。
(3)用户初始化配置,phy_id;
cpsw.c 入参bus.id :cpsw_probe - 》 cpsw_slave_init - 》 am33xx_cpsw_slaves[0].phy_id用户初始化配的值, 在这里,id给prio.slaves
static struct cpsw_slave_data am33xx_cpsw_slaves[] = {
{
.slave_reg_ofs = 0x200,
.sliver_reg_ofs = 0xd80,
.phy_id = "0:19",
.dual_emac_reserved_vlan = CPSW_PORT_VLAN_SLAVE_0,
},
{
.slave_reg_ofs = 0x300,
.sliver_reg_ofs = 0xdc0,
.phy_id = "0:01",
.dual_emac_reserved_vlan = CPSW_PORT_VLAN_SLAVE_1,
},
};
(4).与总线上的id进行匹配名字
cpsw.c cpsw_ndo_open - 》 cpsw_slave_open - 》 phy_connect - 》 bus_find_device_by_name(&mdio_bus_type, NULL, bus_id); 这里bus.id是入参带入的,匹配&mdio_bus_type的bus->id,即上一步的“0:19”
6.协议栈分层结构;
(1)发送函数:
dev.c dev.c cpsw.c
dev_queue_xmit dev_hard_start_xmit cpsw_ndo_start_xmit
(cpsw_netdev_ops)
网络协议接口层 设备驱动功能层 网络物理设备