STRUCT CVMX_USB_PIPE(9)

💖 struct cvmx_usb_pipe(9) 💖

from the Kernel API Manual — okay bestie, let's get into this pipe. 🫶

🎀 NAME 🎀

struct cvmx_usb_pipe — a pipe represents a virtual connection between Octeon and some USB device. It contains a list of pending request to the device. ✨

🌸 SYNOPSIS 🌸

struct cvmx_usb_pipe {
    struct list_head node;
    struct list_head transactions;
    u64 interval;
    u64 next_tx_frame;
    enum cvmx_usb_pipe_flags flags;
    enum cvmx_usb_speed device_speed;
    enum cvmx_usb_transfer transfer_type;
    enum cvmx_usb_direction transfer_dir;
    int multi_count;
    u16 max_packet;
    u8 device_addr;
    u8 endpoint_num;
    u8 hub_device_addr;
    u8 hub_port;
    u8 pid_toggle;
    u8 channel;
    s8 split_sc_frame;
};

💅 Members 💅

okay so every member here is doing its own iconic thing:

• node — List node for pipe list 🧵
• transactions — List of pending transactions 📋
• interval — For periodic pipes, the interval between packets in frames ⏱️
• next_tx_frame — The next frame this pipe is allowed to transmit on 🚦
• flags — State flags for this pipe 🚩
• device_speed — Speed of device connected to this pipe ⚡
• transfer_type — Type of transaction supported by this pipe 🔄
• transfer_dir — IN or OUT. Ignored for Control ↔️
• multi_count — Max packet in a row for the device 📦
• max_packet — The device's maximum packet size in bytes 📏
• device_addr — USB device address at other end of pipe 🔌
• endpoint_num — USB endpoint number at other end of pipe 🔢
• hub_device_addr — Hub address this device is connected to 🛰️
• hub_port — Hub port this device is connected to 🚪
• pid_toggle — This toggles between 0/1 on every packet send to track the data pid needed 🔁
• channel — Hardware DMA channel for this pipe 📡
• split_sc_frame — The low order bits of the frame number the split complete should be sent on 🧩

🔥 SEE ALSO 🔥

Kernel file ./drivers/usb/host/octeon-hcd.c is the main character, and the whole squad is:

• enum cvmx_usb_speed(9)
• enum cvmx_usb_transfer(9)
• enum cvmx_usb_direction(9)
• enum cvmx_usb_status(9)
• struct cvmx_usb_port_status(9)
• struct cvmx_usb_iso_packet(9)
• enum cvmx_usb_initialize_flags(9)
• enum cvmx_usb_pipe_flags(9)
• struct cvmx_usb_transaction(9)
• struct octeon_hcd(9)
• struct octeon_temp_buffer(9)
• octeon_alloc_temp_buffer(9)
• octeon_free_temp_buffer(9)
• octeon_map_urb_for_dma(9)
• octeon_unmap_urb_for_dma(9)

mwah 💋 source/version vibes: ./drivers/usb/host, dated October 2026 — and that's the struct cvmx_usb_pipe(9) page, bestie. 🫶