全志V3s USB控制器驱动分析

科技前沿 • 2025-02-27 10:04 • 阅读 33

大家好，我是讯享网，很高兴认识大家。

USB Controler与USB PHY

参考:
USB芯片到底完成了哪些工作？
usb-phy

设备树节点

ehci0: usb@01c1a000 { compatible = "allwinner,sun8i-v3s-ehci", "generic-ehci"; reg = <0x01c1a000 0x100>; interrupts = <GIC_SPI 72 IRQ_TYPE_LEVEL_HIGH>; clocks = <&ccu CLK_BUS_EHCI0>, <&ccu CLK_BUS_OHCI0>; resets = <&ccu RST_BUS_EHCI0>, <&ccu RST_BUS_OHCI0>; status = "disabled"; }; ohci0: usb@01c1a400 { compatible = "allwinner,sun8i-v3s-ohci", "generic-ohci"; reg = <0x01c1a400 0x100>; interrupts = <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>; clocks = <&ccu CLK_BUS_EHCI0>, <&ccu CLK_BUS_OHCI0>, <&ccu CLK_USB_OHCI0>; resets = <&ccu RST_BUS_EHCI0>, <&ccu RST_BUS_OHCI0>; status = "disabled"; };

讯享网

控制器驱动源码路径

控制器结构体与注册到核心层

linux-5.1.0\include\linux\usb\hcd.h
struct usb_hcd; // usb_hcd —— USB Host Controller Driver
通过usb_create_hcd创建一个usb_hcd对象。

讯享网

linux-5.1.0\drivers\usb\core\hcd.c
int usb_add_hcd(struct usb_hcd *hcd, unsigned int irqnum, unsigned long irqflags)；
将usb_hcd对象加入到usb核心层

硬件连接大概

在这里插入图片描述

core层初始化序列

讯享网linux-5.1.0\drivers\usb\core\usb.c static int __init usb_init(void) retval = bus_register(&usb_bus_type); // struct bus_type usb_bus_typ，其中有match函数匹配驱动与设备 retval = usb_hub_init(); linux-5.1.0\drivers\usb\core\hub.c if (usb_register(&hub_driver) < 0); .probe = hub_probe, // 等待hub device (usb_new_device) hub_wq = alloc_workqueue("usb_hub_wq", WQ_FREEZABLE, 0); // hub_wq 该wq暂时未跑起来

hcd(host controller driver)注册到core层的序列

linux-5.1.0\drivers\usb\host\ohci-platform.c static int ohci_platform_probe(struct platform_device *dev) linux-5.1.0\drivers\usb\core\hcd.c err = usb_add_hcd(hcd, irq, IRQF_SHARED); /* starting here, usbcore will pay attention to this root hub */ retval = register_root_hub(hcd); // root register也是core的hcd中提供 retval = usb_new_device (usb_dev); linux-5.1.0\drivers\usb\core\hub.c err = device_add(&udev->dev); // 添加设备，hub_probe会被调用 hub_probe // hub event的初始化 INIT_WORK(&hub->events, hub_event); // hub_event 会被queue_work触发，传递的参数是hub->events hub_event // 当queue_work触发 hub = container_of(work, struct usb_hub, events); // events只是用来传usb_hub(子类与父类) // hub 的配置 if (hub_configure(hub, &desc->endpoint[0].desc) >= 0) // hub usb中断事件 usb_fill_int_urb(hub->urb, hdev, pipe, *hub->buffer, maxp, hub_irq,hub, endpoint->bInterval); // 当hub usb 中断触发 static void hub_irq(struct urb *urb) // 触发hub event kick_hub_wq(hub); usb_hc_died (hcd) linux-5.1.0\drivers\usb\core\hub.c // hub与hcd一样，是core中独立的一个文件 /* make hub_wq clean up old urbs and devices */ usb_set_device_state (hcd->self.root_hub, USB_STATE_NOTATTACHED); usb_kick_hub_wq(hcd->self.root_hub); // 触发hub event kick_hub_wq(hub); if (queue_work(hub_wq, &hub->events)) // hub_wq, 就是core层初始化时候的wq static void hub_event(struct work_struct *work) // 处理hub事件