1 // SPDX-License-Identifier: GPL-2.0
2 /* Target based USB-Gadget
3  *
4  * UAS protocol handling, target callbacks, configfs handling,
5  * BBB (USB Mass Storage Class Bulk-Only (BBB) and Transport protocol handling.
6  *
7  * Author: Sebastian Andrzej Siewior <bigeasy at linutronix dot de>
8  */
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/types.h>
12 #include <linux/string.h>
13 #include <linux/configfs.h>
14 #include <linux/ctype.h>
15 #include <linux/usb/ch9.h>
16 #include <linux/usb/composite.h>
17 #include <linux/usb/gadget.h>
18 #include <linux/usb/storage.h>
19 #include <scsi/scsi_tcq.h>
20 #include <target/target_core_base.h>
21 #include <target/target_core_fabric.h>
22 #include <asm/unaligned.h>
23 
24 #include "u_tcm.h"
25 
26 USB_GADGET_COMPOSITE_OPTIONS();
27 
28 #define UAS_VENDOR_ID	0x0525	/* NetChip */
29 #define UAS_PRODUCT_ID	0xa4a5	/* Linux-USB File-backed Storage Gadget */
30 
31 static struct usb_device_descriptor usbg_device_desc = {
32 	.bLength =		sizeof(usbg_device_desc),
33 	.bDescriptorType =	USB_DT_DEVICE,
34 	/* .bcdUSB = DYNAMIC */
35 	.bDeviceClass =		USB_CLASS_PER_INTERFACE,
36 	.idVendor =		cpu_to_le16(UAS_VENDOR_ID),
37 	.idProduct =		cpu_to_le16(UAS_PRODUCT_ID),
38 	.bNumConfigurations =   1,
39 };
40 
41 #define USB_G_STR_CONFIG USB_GADGET_FIRST_AVAIL_IDX
42 
43 static struct usb_string	usbg_us_strings[] = {
44 	[USB_GADGET_MANUFACTURER_IDX].s	= "Target Manufacturer",
45 	[USB_GADGET_PRODUCT_IDX].s	= "Target Product",
46 	[USB_GADGET_SERIAL_IDX].s	= "000000000001",
47 	[USB_G_STR_CONFIG].s		= "default config",
48 	{ },
49 };
50 
51 static struct usb_gadget_strings usbg_stringtab = {
52 	.language = 0x0409,
53 	.strings = usbg_us_strings,
54 };
55 
56 static struct usb_gadget_strings *usbg_strings[] = {
57 	&usbg_stringtab,
58 	NULL,
59 };
60 
61 static struct usb_function_instance *fi_tcm;
62 static struct usb_function *f_tcm;
63 
64 static int guas_unbind(struct usb_composite_dev *cdev)
65 {
66 	if (!IS_ERR_OR_NULL(f_tcm))
67 		usb_put_function(f_tcm);
68 
69 	return 0;
70 }
71 
72 static int tcm_do_config(struct usb_configuration *c)
73 {
74 	int status;
75 
76 	f_tcm = usb_get_function(fi_tcm);
77 	if (IS_ERR(f_tcm))
78 		return PTR_ERR(f_tcm);
79 
80 	status = usb_add_function(c, f_tcm);
81 	if (status < 0) {
82 		usb_put_function(f_tcm);
83 		return status;
84 	}
85 
86 	return 0;
87 }
88 
89 static struct usb_configuration usbg_config_driver = {
90 	.label                  = "Linux Target",
91 	.bConfigurationValue    = 1,
92 	.bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
93 };
94 
95 static int usbg_attach(struct usb_function_instance *f);
96 static void usbg_detach(struct usb_function_instance *f);
97 
98 static int usb_target_bind(struct usb_composite_dev *cdev)
99 {
100 	int ret;
101 
102 	ret = usb_string_ids_tab(cdev, usbg_us_strings);
103 	if (ret)
104 		return ret;
105 
106 	usbg_device_desc.iManufacturer =
107 		usbg_us_strings[USB_GADGET_MANUFACTURER_IDX].id;
108 	usbg_device_desc.iProduct = usbg_us_strings[USB_GADGET_PRODUCT_IDX].id;
109 	usbg_device_desc.iSerialNumber =
110 		usbg_us_strings[USB_GADGET_SERIAL_IDX].id;
111 	usbg_config_driver.iConfiguration =
112 		usbg_us_strings[USB_G_STR_CONFIG].id;
113 
114 	ret = usb_add_config(cdev, &usbg_config_driver, tcm_do_config);
115 	if (ret)
116 		return ret;
117 	usb_composite_overwrite_options(cdev, &coverwrite);
118 	return 0;
119 }
120 
121 static struct usb_composite_driver usbg_driver = {
122 	.name           = "g_target",
123 	.dev            = &usbg_device_desc,
124 	.strings        = usbg_strings,
125 	.max_speed      = USB_SPEED_SUPER,
126 	.bind		= usb_target_bind,
127 	.unbind         = guas_unbind,
128 };
129 
130 static int usbg_attach(struct usb_function_instance *f)
131 {
132 	return usb_composite_probe(&usbg_driver);
133 }
134 
135 static void usbg_detach(struct usb_function_instance *f)
136 {
137 	usb_composite_unregister(&usbg_driver);
138 }
139 
140 static int __init usb_target_gadget_init(void)
141 {
142 	struct f_tcm_opts *tcm_opts;
143 
144 	fi_tcm = usb_get_function_instance("tcm");
145 	if (IS_ERR(fi_tcm))
146 		return PTR_ERR(fi_tcm);
147 
148 	tcm_opts = container_of(fi_tcm, struct f_tcm_opts, func_inst);
149 	mutex_lock(&tcm_opts->dep_lock);
150 	tcm_opts->tcm_register_callback = usbg_attach;
151 	tcm_opts->tcm_unregister_callback = usbg_detach;
152 	tcm_opts->dependent = THIS_MODULE;
153 	tcm_opts->can_attach = true;
154 	tcm_opts->has_dep = true;
155 	mutex_unlock(&tcm_opts->dep_lock);
156 
157 	fi_tcm->set_inst_name(fi_tcm, "tcm-legacy");
158 
159 	return 0;
160 }
161 module_init(usb_target_gadget_init);
162 
163 static void __exit usb_target_gadget_exit(void)
164 {
165 	if (!IS_ERR_OR_NULL(fi_tcm))
166 		usb_put_function_instance(fi_tcm);
167 
168 }
169 module_exit(usb_target_gadget_exit);
170 
171 MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>");
172 MODULE_DESCRIPTION("usb-gadget fabric");
173 MODULE_LICENSE("GPL v2");
174