xhci 寄存器介绍

查看linux 代码：

1733 /* There is one xhci_hcd structure per controller */
1734 struct xhci_hcd {
1735     struct usb_hcd *main_hcd;
1736     struct usb_hcd *shared_hcd;
1737     /* glue to PCI and HCD framework */
1738     struct xhci_cap_regs __iomem *cap_regs;
1739     struct xhci_op_regs __iomem *op_regs;
1740     struct xhci_run_regs __iomem *run_regs;
1741     struct xhci_doorbell_array __iomem *dba;
1742     /* Our HCD's current interrupter register set */
1743     struct  xhci_intr_reg __iomem *ir_set;

主要寄存器是：xhci_cap_regs， xhci_op_regs， xhci_run_regs，xhci_doorbell_array

  50 struct xhci_cap_regs {51     __le32  hc_capbase;52     __le32  hcs_params1;53     __le32  hcs_params2;54     __le32  hcs_params3;55     __le32  hcc_params;56     __le32  db_off;57     __le32  run_regs_off;58     __le32  hcc_params2; /* xhci 1.1 */59     /* Reserved up to (CAPLENGTH - 0x1C) */60 };

对应手册是

 176 struct xhci_op_regs {177     __le32  command;178     __le32  status;179     __le32  page_size;180     __le32  reserved1;181     __le32  reserved2;182     __le32  dev_notification;183     __le64  cmd_ring;184     /* rsvd: offset 0x20-2F */185     __le32  reserved3[4];186     __le64  dcbaa_ptr;187     __le32  config_reg;188     /* rsvd: offset 0x3C-3FF */189     __le32  reserved4[241];190     /* port 1 registers, which serve as a base address for other ports */191     __le32  port_status_base;192     __le32  port_power_base;193     __le32  port_link_base;194     __le32  reserved5;195     /* registers for ports 2-255 */196     __le32  reserved6[NUM_PORT_REGS*254];197 };

对用手册是：

其中端口寄存器：

寄存器读写实操

root@raoxu-PC:/sys# lspci | grep -i usb
00:14.0 USB controller: Intel Corporation Comet Lake PCH-V USB Controller
root@raoxu-PC:/sys# lspci -s 00:14.0 -v
00:14.0 USB controller: Intel Corporation Comet Lake PCH-V USB Controller (prog-if 30 [XHCI])Subsystem: ASRock Incorporation Device a3afFlags: bus master, medium devsel, latency 0, IRQ 122Memory at 99330000 (64-bit, non-prefetchable) [size=64K]Capabilities: [70] Power Management version 2Capabilities: [80] MSI: Enable+ Count=1/8 Maskable- 64bit+Kernel driver in use: xhci_hcd

首先查看xhci 寄存器基地址为：0x99330000
也可以通过其他方式获取到：

cat /proc/iomem | grep xhci99330000-9933ffff : xhci-hcd

读取 Operational Register Space 首地址：


根据代码和手册可以找到，需要找到Host Controller Operational Registers的地址偏移为：

root@raoxu-PC:/sys# busybox devmem 0x99330000 
0x01000080

读出来的偏移值0x80
那么偏移地址就是0x99330080

那么如何得到port的地址呢：

根据介绍，我们只需要根据port num 进行计算就可以了。
以我插入的鼠标为例：

/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/8p, 5000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/12p, 480M|__ Port 1: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M|__ Port 5: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 12M|__ Port 5: Dev 3, If 1, Class=Human Interface Device, Driver=usbhid, 12M|__ Port 10: Dev 4, If 0, Class=Hub, Driver=hub/4p, 480M|__ Port 3: Dev 8, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M

如何port 为 10
那么基地址为：addr = 0x99330080 + (0x400 + 0x10 * (10 -1)) = 0x99330510
那么读取状态：

root@raoxu-PC:/sys# busybox devmem 0x99330510 
0x00000E03

最高位写1 进行复位

root@raoxu-PC:/sys# busybox devmem 0x99330510 32 0x80000E03
root@raoxu-PC:/sys# busybox devmem 0x99330510 
0x000006E1

输入命令可以看到设备复位了