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 8 #include <linux/gfp.h> 9 #include <linux/kernel.h> 10 #include <linux/tty.h> 11 #include <linux/module.h> 12 #include <linux/usb.h> 13 #include <linux/usb/serial.h> 14 15 #define USB_DEBUG_MAX_PACKET_SIZE 8 16 #define USB_DEBUG_BRK_SIZE 8 17 static const char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = { 18 0x00, 19 0xff, 20 0x01, 21 0xfe, 22 0x00, 23 0xfe, 24 0x01, 25 0xff, 26 }; 27 28 static const struct usb_device_id id_table[] = { 29 { USB_DEVICE(0x0525, 0x127a) }, 30 { }, 31 }; 32 33 static const struct usb_device_id dbc_id_table[] = { 34 { USB_DEVICE(0x1d6b, 0x0010) }, 35 { USB_DEVICE(0x1d6b, 0x0011) }, 36 { }, 37 }; 38 39 static const struct usb_device_id id_table_combined[] = { 40 { USB_DEVICE(0x0525, 0x127a) }, 41 { USB_DEVICE(0x1d6b, 0x0010) }, 42 { USB_DEVICE(0x1d6b, 0x0011) }, 43 { }, 44 }; 45 MODULE_DEVICE_TABLE(usb, id_table_combined); 46 47 /* This HW really does not support a serial break, so one will be 48 * emulated when ever the break state is set to true. 49 */ 50 static int usb_debug_break_ctl(struct tty_struct *tty, int break_state) 51 { 52 struct usb_serial_port *port = tty->driver_data; 53 int ret; 54 55 if (!break_state) 56 return 0; 57 58 ret = usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE); 59 if (ret < 0) 60 return ret; 61 62 return 0; 63 } 64 65 static void usb_debug_process_read_urb(struct urb *urb) 66 { 67 struct usb_serial_port *port = urb->context; 68 69 if (urb->actual_length == USB_DEBUG_BRK_SIZE && 70 memcmp(urb->transfer_buffer, USB_DEBUG_BRK, 71 USB_DEBUG_BRK_SIZE) == 0) { 72 usb_serial_handle_break(port); 73 return; 74 } 75 76 usb_serial_generic_process_read_urb(urb); 77 } 78 79 static void usb_debug_init_termios(struct tty_struct *tty) 80 { 81 tty->termios.c_lflag &= ~(ECHO | ECHONL); 82 } 83 84 static struct usb_serial_driver debug_device = { 85 .driver = { 86 .name = "debug", 87 }, 88 .id_table = id_table, 89 .num_ports = 1, 90 .bulk_out_size = USB_DEBUG_MAX_PACKET_SIZE, 91 .break_ctl = usb_debug_break_ctl, 92 .init_termios = usb_debug_init_termios, 93 .process_read_urb = usb_debug_process_read_urb, 94 }; 95 96 static struct usb_serial_driver dbc_device = { 97 .driver = { 98 .name = "xhci_dbc", 99 }, 100 .id_table = dbc_id_table, 101 .num_ports = 1, 102 .break_ctl = usb_debug_break_ctl, 103 .init_termios = usb_debug_init_termios, 104 .process_read_urb = usb_debug_process_read_urb, 105 }; 106 107 static struct usb_serial_driver * const serial_drivers[] = { 108 &debug_device, &dbc_device, NULL 109 }; 110 111 module_usb_serial_driver(serial_drivers, id_table_combined); 112 MODULE_DESCRIPTION("USB Debug cable driver"); 113 MODULE_LICENSE("GPL v2"); 114