1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * USB Debug cable driver 4 * 5 * Copyright (C) 2006 Greg Kroah-Hartman <greg@kroah.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License version 9 * 2 as published by the Free Software Foundation. 10 */ 11 12 #include <linux/gfp.h> 13 #include <linux/kernel.h> 14 #include <linux/tty.h> 15 #include <linux/module.h> 16 #include <linux/usb.h> 17 #include <linux/usb/serial.h> 18 19 #define USB_DEBUG_MAX_PACKET_SIZE 8 20 #define USB_DEBUG_BRK_SIZE 8 21 static const char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = { 22 0x00, 23 0xff, 24 0x01, 25 0xfe, 26 0x00, 27 0xfe, 28 0x01, 29 0xff, 30 }; 31 32 static const struct usb_device_id id_table[] = { 33 { USB_DEVICE(0x0525, 0x127a) }, 34 { }, 35 }; 36 37 static const struct usb_device_id dbc_id_table[] = { 38 { USB_DEVICE(0x1d6b, 0x0004) }, 39 { }, 40 }; 41 42 static const struct usb_device_id id_table_combined[] = { 43 { USB_DEVICE(0x0525, 0x127a) }, 44 { USB_DEVICE(0x1d6b, 0x0004) }, 45 { }, 46 }; 47 MODULE_DEVICE_TABLE(usb, id_table_combined); 48 49 /* This HW really does not support a serial break, so one will be 50 * emulated when ever the break state is set to true. 51 */ 52 static void usb_debug_break_ctl(struct tty_struct *tty, int break_state) 53 { 54 struct usb_serial_port *port = tty->driver_data; 55 if (!break_state) 56 return; 57 usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE); 58 } 59 60 static void usb_debug_process_read_urb(struct urb *urb) 61 { 62 struct usb_serial_port *port = urb->context; 63 64 if (urb->actual_length == USB_DEBUG_BRK_SIZE && 65 memcmp(urb->transfer_buffer, USB_DEBUG_BRK, 66 USB_DEBUG_BRK_SIZE) == 0) { 67 usb_serial_handle_break(port); 68 return; 69 } 70 71 usb_serial_generic_process_read_urb(urb); 72 } 73 74 static struct usb_serial_driver debug_device = { 75 .driver = { 76 .owner = THIS_MODULE, 77 .name = "debug", 78 }, 79 .id_table = id_table, 80 .num_ports = 1, 81 .bulk_out_size = USB_DEBUG_MAX_PACKET_SIZE, 82 .break_ctl = usb_debug_break_ctl, 83 .process_read_urb = usb_debug_process_read_urb, 84 }; 85 86 static struct usb_serial_driver dbc_device = { 87 .driver = { 88 .owner = THIS_MODULE, 89 .name = "xhci_dbc", 90 }, 91 .id_table = dbc_id_table, 92 .num_ports = 1, 93 .break_ctl = usb_debug_break_ctl, 94 .process_read_urb = usb_debug_process_read_urb, 95 }; 96 97 static struct usb_serial_driver * const serial_drivers[] = { 98 &debug_device, &dbc_device, NULL 99 }; 100 101 module_usb_serial_driver(serial_drivers, id_table_combined); 102 MODULE_LICENSE("GPL"); 103