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ncm.c
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1 /*
2  * ncm.c -- NCM gadget driver
3  *
4  * Copyright (C) 2010 Nokia Corporation
5  * Contact: Yauheni Kaliuta <[email protected]>
6  *
7  * The driver borrows from ether.c which is:
8  *
9  * Copyright (C) 2003-2005,2008 David Brownell
10  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
11  * Copyright (C) 2008 Nokia Corporation
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License as published by
15  * the Free Software Foundation; either version 2 of the License, or
16  * (at your option) any later version.
17  */
18 
19 /* #define DEBUG */
20 /* #define VERBOSE_DEBUG */
21 
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/usb/composite.h>
25 
26 #include "u_ether.h"
27 
28 #define DRIVER_DESC "NCM Gadget"
29 
30 /*-------------------------------------------------------------------------*/
31 
32 /*
33  * Kbuild is not very cooperative with respect to linking separately
34  * compiled library objects into one module. So for now we won't use
35  * separate compilation ... ensuring init/exit sections work to shrink
36  * the runtime footprint, and giving us at least some parts of what
37  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
38  */
39 #include "f_ncm.c"
40 #include "u_ether.c"
41 
42 /*-------------------------------------------------------------------------*/
43 
44 /* DO NOT REUSE THESE IDs with a protocol-incompatible driver!! Ever!!
45  * Instead: allocate your own, using normal USB-IF procedures.
46  */
47 
48 /* Thanks to NetChip Technologies for donating this product ID.
49  * It's for devices with only CDC Ethernet configurations.
50  */
51 #define CDC_VENDOR_NUM 0x0525 /* NetChip */
52 #define CDC_PRODUCT_NUM 0xa4a1 /* Linux-USB Ethernet Gadget */
53 
54 /*-------------------------------------------------------------------------*/
56 
57 static struct usb_device_descriptor device_desc = {
58  .bLength = sizeof device_desc,
60 
61  .bcdUSB = cpu_to_le16 (0x0200),
62 
63  .bDeviceClass = USB_CLASS_COMM,
64  .bDeviceSubClass = 0,
65  .bDeviceProtocol = 0,
66  /* .bMaxPacketSize0 = f(hardware) */
67 
68  /* Vendor and product id defaults change according to what configs
69  * we support. (As does bNumConfigurations.) These values can
70  * also be overridden by module parameters.
71  */
72  .idVendor = cpu_to_le16 (CDC_VENDOR_NUM),
73  .idProduct = cpu_to_le16 (CDC_PRODUCT_NUM),
74  /* .bcdDevice = f(hardware) */
75  /* .iManufacturer = DYNAMIC */
76  /* .iProduct = DYNAMIC */
77  /* NO SERIAL NUMBER */
78  .bNumConfigurations = 1,
79 };
80 
81 static struct usb_otg_descriptor otg_descriptor = {
82  .bLength = sizeof otg_descriptor,
84 
85  /* REVISIT SRP-only hardware is possible, although
86  * it would not be called "OTG" ...
87  */
88  .bmAttributes = USB_OTG_SRP | USB_OTG_HNP,
89 };
90 
91 static const struct usb_descriptor_header *otg_desc[] = {
92  (struct usb_descriptor_header *) &otg_descriptor,
93  NULL,
94 };
95 
96 /* string IDs are assigned dynamically */
97 static struct usb_string strings_dev[] = {
100  [USB_GADGET_SERIAL_IDX].s = "",
101  { } /* end of list */
102 };
103 
104 static struct usb_gadget_strings stringtab_dev = {
105  .language = 0x0409, /* en-us */
106  .strings = strings_dev,
107 };
108 
109 static struct usb_gadget_strings *dev_strings[] = {
110  &stringtab_dev,
111  NULL,
112 };
113 
114 static u8 hostaddr[ETH_ALEN];
115 
116 /*-------------------------------------------------------------------------*/
117 
118 static int __init ncm_do_config(struct usb_configuration *c)
119 {
120  /* FIXME alloc iConfiguration string, set it in c->strings */
121 
122  if (gadget_is_otg(c->cdev->gadget)) {
123  c->descriptors = otg_desc;
125  }
126 
127  return ncm_bind_config(c, hostaddr);
128 }
129 
130 static struct usb_configuration ncm_config_driver = {
131  /* .label = f(hardware) */
132  .label = "CDC Ethernet (NCM)",
133  .bConfigurationValue = 1,
134  /* .iConfiguration = DYNAMIC */
135  .bmAttributes = USB_CONFIG_ATT_SELFPOWER,
136 };
137 
138 /*-------------------------------------------------------------------------*/
139 
140 static int __init gncm_bind(struct usb_composite_dev *cdev)
141 {
142  struct usb_gadget *gadget = cdev->gadget;
143  int status;
144 
145  /* set up network link layer */
146  status = gether_setup(cdev->gadget, hostaddr);
147  if (status < 0)
148  return status;
149 
150  /* Allocate string descriptor numbers ... note that string
151  * contents can be overridden by the composite_dev glue.
152  */
153 
154  status = usb_string_ids_tab(cdev, strings_dev);
155  if (status < 0)
156  goto fail;
157  device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
158  device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
159 
160  status = usb_add_config(cdev, &ncm_config_driver,
161  ncm_do_config);
162  if (status < 0)
163  goto fail;
164 
165  usb_composite_overwrite_options(cdev, &coverwrite);
166  dev_info(&gadget->dev, "%s\n", DRIVER_DESC);
167 
168  return 0;
169 
170 fail:
171  gether_cleanup();
172  return status;
173 }
174 
175 static int __exit gncm_unbind(struct usb_composite_dev *cdev)
176 {
177  gether_cleanup();
178  return 0;
179 }
180 
181 static __refdata struct usb_composite_driver ncm_driver = {
182  .name = "g_ncm",
183  .dev = &device_desc,
184  .strings = dev_strings,
185  .max_speed = USB_SPEED_HIGH,
186  .bind = gncm_bind,
187  .unbind = __exit_p(gncm_unbind),
188 };
189 
191 MODULE_AUTHOR("Yauheni Kaliuta");
192 MODULE_LICENSE("GPL");
193 
194 static int __init init(void)
195 {
196  return usb_composite_probe(&ncm_driver);
197 }
199 
200 static void __exit cleanup(void)
201 {
202  usb_composite_unregister(&ncm_driver);
203 }
204 module_exit(cleanup);