1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * mass_storage.c -- Mass Storage USB Gadget
4 *
5 * Copyright (C) 2003-2008 Alan Stern
6 * Copyright (C) 2009 Samsung Electronics
7 * Author: Michal Nazarewicz <mina86@mina86.com>
8 * All rights reserved.
9 */
10
11
12/*
13 * The Mass Storage Gadget acts as a USB Mass Storage device,
14 * appearing to the host as a disk drive or as a CD-ROM drive. In
15 * addition to providing an example of a genuinely useful gadget
16 * driver for a USB device, it also illustrates a technique of
17 * double-buffering for increased throughput. Last but not least, it
18 * gives an easy way to probe the behavior of the Mass Storage drivers
19 * in a USB host.
20 *
21 * Since this file serves only administrative purposes and all the
22 * business logic is implemented in f_mass_storage.* file. Read
23 * comments in this file for more detailed description.
24 */
25
26
27#include <linux/kernel.h>
28#include <linux/usb/ch9.h>
29#include <linux/module.h>
30
31/*-------------------------------------------------------------------------*/
32
33#define DRIVER_DESC "Mass Storage Gadget"
34#define DRIVER_VERSION "2009/09/11"
35
36/*
37 * Thanks to NetChip Technologies for donating this product ID.
38 *
39 * DO NOT REUSE THESE IDs with any other driver!! Ever!!
40 * Instead: allocate your own, using normal USB-IF procedures.
41 */
42#define FSG_VENDOR_ID 0x0525 /* NetChip */
43#define FSG_PRODUCT_ID 0xa4a5 /* Linux-USB File-backed Storage Gadget */
44
45#include "f_mass_storage.h"
46
47/*-------------------------------------------------------------------------*/
48USB_GADGET_COMPOSITE_OPTIONS();
49
50static struct usb_device_descriptor msg_device_desc = {
51 .bLength = sizeof msg_device_desc,
52 .bDescriptorType = USB_DT_DEVICE,
53
54 /* .bcdUSB = DYNAMIC */
55 .bDeviceClass = USB_CLASS_PER_INTERFACE,
56
57 /* Vendor and product id can be overridden by module parameters. */
58 .idVendor = cpu_to_le16(FSG_VENDOR_ID),
59 .idProduct = cpu_to_le16(FSG_PRODUCT_ID),
60 .bNumConfigurations = 1,
61};
62
63static const struct usb_descriptor_header *otg_desc[2];
64
65static struct usb_string strings_dev[] = {
66 [USB_GADGET_MANUFACTURER_IDX].s = "",
67 [USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
68 [USB_GADGET_SERIAL_IDX].s = "",
69 { } /* end of list */
70};
71
72static struct usb_gadget_strings stringtab_dev = {
73 .language = 0x0409, /* en-us */
74 .strings = strings_dev,
75};
76
77static struct usb_gadget_strings *dev_strings[] = {
78 &stringtab_dev,
79 NULL,
80};
81
82static struct usb_function_instance *fi_msg;
83static struct usb_function *f_msg;
84
85/****************************** Configurations ******************************/
86
87static struct fsg_module_parameters mod_data = {
88 .stall = 1
89};
90#ifdef CONFIG_USB_GADGET_DEBUG_FILES
91
92static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
93
94#else
95
96/*
97 * Number of buffers we will use.
98 * 2 is usually enough for good buffering pipeline
99 */
100#define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
101
102#endif /* CONFIG_USB_GADGET_DEBUG_FILES */
103
104FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
105
106static int msg_do_config(struct usb_configuration *c)
107{
108 int ret;
109
110 if (gadget_is_otg(g: c->cdev->gadget)) {
111 c->descriptors = otg_desc;
112 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
113 }
114
115 f_msg = usb_get_function(fi: fi_msg);
116 if (IS_ERR(ptr: f_msg))
117 return PTR_ERR(ptr: f_msg);
118
119 ret = usb_add_function(c, f_msg);
120 if (ret)
121 goto put_func;
122
123 return 0;
124
125put_func:
126 usb_put_function(f: f_msg);
127 return ret;
128}
129
130static struct usb_configuration msg_config_driver = {
131 .label = "Linux File-Backed Storage",
132 .bConfigurationValue = 1,
133 .bmAttributes = USB_CONFIG_ATT_SELFPOWER,
134};
135
136
137/****************************** Gadget Bind ******************************/
138
139static int msg_bind(struct usb_composite_dev *cdev)
140{
141 struct fsg_opts *opts;
142 struct fsg_config config;
143 int status;
144
145 fi_msg = usb_get_function_instance(name: "mass_storage");
146 if (IS_ERR(ptr: fi_msg))
147 return PTR_ERR(ptr: fi_msg);
148
149 fsg_config_from_params(cfg: &config, params: &mod_data, fsg_num_buffers);
150 opts = fsg_opts_from_func_inst(fi: fi_msg);
151
152 opts->no_configfs = true;
153 status = fsg_common_set_num_buffers(common: opts->common, n: fsg_num_buffers);
154 if (status)
155 goto fail;
156
157 status = fsg_common_set_cdev(common: opts->common, cdev, can_stall: config.can_stall);
158 if (status)
159 goto fail_set_cdev;
160
161 fsg_common_set_sysfs(common: opts->common, sysfs: true);
162 status = fsg_common_create_luns(common: opts->common, cfg: &config);
163 if (status)
164 goto fail_set_cdev;
165
166 fsg_common_set_inquiry_string(common: opts->common, vn: config.vendor_name,
167 pn: config.product_name);
168
169 status = usb_string_ids_tab(c: cdev, str: strings_dev);
170 if (status < 0)
171 goto fail_string_ids;
172 msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
173
174 if (gadget_is_otg(g: cdev->gadget) && !otg_desc[0]) {
175 struct usb_descriptor_header *usb_desc;
176
177 usb_desc = usb_otg_descriptor_alloc(gadget: cdev->gadget);
178 if (!usb_desc) {
179 status = -ENOMEM;
180 goto fail_string_ids;
181 }
182 usb_otg_descriptor_init(gadget: cdev->gadget, otg_desc: usb_desc);
183 otg_desc[0] = usb_desc;
184 otg_desc[1] = NULL;
185 }
186
187 status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
188 if (status < 0)
189 goto fail_otg_desc;
190
191 usb_composite_overwrite_options(cdev, covr: &coverwrite);
192 dev_info(&cdev->gadget->dev,
193 DRIVER_DESC ", version: " DRIVER_VERSION "\n");
194 return 0;
195
196fail_otg_desc:
197 kfree(objp: otg_desc[0]);
198 otg_desc[0] = NULL;
199fail_string_ids:
200 fsg_common_remove_luns(common: opts->common);
201fail_set_cdev:
202 fsg_common_free_buffers(common: opts->common);
203fail:
204 usb_put_function_instance(fi: fi_msg);
205 return status;
206}
207
208static int msg_unbind(struct usb_composite_dev *cdev)
209{
210 if (!IS_ERR(ptr: f_msg))
211 usb_put_function(f: f_msg);
212
213 if (!IS_ERR(ptr: fi_msg))
214 usb_put_function_instance(fi: fi_msg);
215
216 kfree(objp: otg_desc[0]);
217 otg_desc[0] = NULL;
218
219 return 0;
220}
221
222/****************************** Some noise ******************************/
223
224static struct usb_composite_driver msg_driver = {
225 .name = "g_mass_storage",
226 .dev = &msg_device_desc,
227 .max_speed = USB_SPEED_SUPER_PLUS,
228 .needs_serial = 1,
229 .strings = dev_strings,
230 .bind = msg_bind,
231 .unbind = msg_unbind,
232};
233
234module_usb_composite_driver(msg_driver);
235
236MODULE_DESCRIPTION(DRIVER_DESC);
237MODULE_AUTHOR("Michal Nazarewicz");
238MODULE_LICENSE("GPL");
239

source code of linux/drivers/usb/gadget/legacy/mass_storage.c