STRUCT ES2_AP_DEV(9)

okay so bestie, welcome to the struct es2_ap_dev(9) page from the Kernel API Manual 💖 this is the ES2 USB Bridge to AP structure, and we're gonna go through every single member like it's a group chat recap — no cap, nothing skipped ✨

🌸 NAME 🌸

struct es2_ap_dev — ES2 USB Bridge to AP structure 🦋

✨ SYNOPSIS ✨

struct es2_ap_dev {
    struct usb_device *usb_dev;
    struct usb_interface *usb_intf;
    struct gb_host_device *hd;
    struct es2_cport_in cport_in;
    __u8 cport_out_endpoint;
    struct urb *cport_out_urb[NUM_CPORT_OUT_URB];
    bool cport_out_urb_busy[NUM_CPORT_OUT_URB];
    bool cport_out_urb_cancelled[NUM_CPORT_OUT_URB];
    spinlock_t cport_out_urb_lock;
    bool cdsi1_in_use;
    struct task_struct *apb_log_task;
    struct dentry *apb_log_dentry;
    struct dentry *apb_log_enable_dentry;
    char *apb_log_fifo;
    __u8 arpc_endpoint_in;
    struct urb *arpc_urb[NUM_ARPC_IN_URB];
    u8 *arpc_buffer[NUM_ARPC_IN_URB];
    int arpc_id_cycle;
    spinlock_t arpc_lock;
    struct list_head arpcs;
};

🫶 Members 🫶

• usb_dev — pointer to the USB device we are. literally us, main character energy 💅
• usb_intf — pointer to the USB interface we are bound to.
• hd — pointer to our gb_host_device structure.
• cport_in — endpoint, urbs and buffer for cport in messages.
• cport_out_endpoint — endpoint for cport out messages.
• cport_out_urb — array of urbs for the CPort out messages.
• cport_out_urb_busy — array of flags to see if the cport_out_urb is busy or not.
• cport_out_urb_cancelled — array of flags indicating whether the corresponding cport_out_urb is being cancelled.
• cport_out_urb_lock — locks the cport_out_urb_busy "list".
• cdsi1_in_use — true if cport CDSI1 is in use.
• apb_log_task — task pointer for logging thread.
• apb_log_dentry — file system entry for the log file interface.
• apb_log_enable_dentry — file system entry for enabling logging.
• apb_log_fifo — kernel FIFO to carry logged data.
• arpc_endpoint_in — bulk in endpoint for APBridgeA RPC.
• arpc_urb — array of urbs for the ARPC in messages.
• arpc_buffer — array of buffers for the arpc_urb urbs.
• arpc_id_cycle — gives an unique id to ARPC. iykyk 👑
• arpc_lock — locks ARPC list.
• arpcs — list of in progress ARPCs.

🦋 SEE ALSO 🦋

Kernel file ./drivers/greybus/es2.c — go read it, bestie, it's giving source-of-truth energy 🔥

mwah 💋 this lil page comes from ./drivers/greybus, dated October 2026, and it's all about struct es2_ap_dev(9) — bye bestie, slay your kernel adventures! 🎀✨