root/drivers/usb/gadget/legacy/mass_storage.c

DEFINITIONS

1. msg_do_config
2. msg_bind
3. msg_unbind
4. msg_init
5. msg_cleanup

   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 /*-------------------------------------------------------------------------*/
  48 USB_GADGET_COMPOSITE_OPTIONS();
  49 
  50 static 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 
  63 static const struct usb_descriptor_header *otg_desc[2];
  64 
  65 static 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 
  72 static struct usb_gadget_strings stringtab_dev = {
  73         .language       = 0x0409,       /* en-us */
  74         .strings        = strings_dev,
  75 };
  76 
  77 static struct usb_gadget_strings *dev_strings[] = {
  78         &stringtab_dev,
  79         NULL,
  80 };
  81 
  82 static struct usb_function_instance *fi_msg;
  83 static struct usb_function *f_msg;
  84 
  85 /****************************** Configurations ******************************/
  86 
  87 static struct fsg_module_parameters mod_data = {
  88         .stall = 1
  89 };
  90 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
  91 
  92 static 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 
 104 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 105 
 106 static int msg_do_config(struct usb_configuration *c)
 107 {
 108         struct fsg_opts *opts;
 109         int ret;
 110 
 111         if (gadget_is_otg(c->cdev->gadget)) {
 112                 c->descriptors = otg_desc;
 113                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 114         }
 115 
 116         opts = fsg_opts_from_func_inst(fi_msg);
 117 
 118         f_msg = usb_get_function(fi_msg);
 119         if (IS_ERR(f_msg))
 120                 return PTR_ERR(f_msg);
 121 
 122         ret = usb_add_function(c, f_msg);
 123         if (ret)
 124                 goto put_func;
 125 
 126         return 0;
 127 
 128 put_func:
 129         usb_put_function(f_msg);
 130         return ret;
 131 }
 132 
 133 static struct usb_configuration msg_config_driver = {
 134         .label                  = "Linux File-Backed Storage",
 135         .bConfigurationValue    = 1,
 136         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 137 };
 138 
 139 
 140 /****************************** Gadget Bind ******************************/
 141 
 142 static int msg_bind(struct usb_composite_dev *cdev)
 143 {
 144         struct fsg_opts *opts;
 145         struct fsg_config config;
 146         int status;
 147 
 148         fi_msg = usb_get_function_instance("mass_storage");
 149         if (IS_ERR(fi_msg))
 150                 return PTR_ERR(fi_msg);
 151 
 152         fsg_config_from_params(&config, &mod_data, fsg_num_buffers);
 153         opts = fsg_opts_from_func_inst(fi_msg);
 154 
 155         opts->no_configfs = true;
 156         status = fsg_common_set_num_buffers(opts->common, fsg_num_buffers);
 157         if (status)
 158                 goto fail;
 159 
 160         status = fsg_common_set_cdev(opts->common, cdev, config.can_stall);
 161         if (status)
 162                 goto fail_set_cdev;
 163 
 164         fsg_common_set_sysfs(opts->common, true);
 165         status = fsg_common_create_luns(opts->common, &config);
 166         if (status)
 167                 goto fail_set_cdev;
 168 
 169         fsg_common_set_inquiry_string(opts->common, config.vendor_name,
 170                                       config.product_name);
 171 
 172         status = usb_string_ids_tab(cdev, strings_dev);
 173         if (status < 0)
 174                 goto fail_string_ids;
 175         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 176 
 177         if (gadget_is_otg(cdev->gadget) && !otg_desc[0]) {
 178                 struct usb_descriptor_header *usb_desc;
 179 
 180                 usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
 181                 if (!usb_desc)
 182                         goto fail_string_ids;
 183                 usb_otg_descriptor_init(cdev->gadget, usb_desc);
 184                 otg_desc[0] = usb_desc;
 185                 otg_desc[1] = NULL;
 186         }
 187 
 188         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 189         if (status < 0)
 190                 goto fail_otg_desc;
 191 
 192         usb_composite_overwrite_options(cdev, &coverwrite);
 193         dev_info(&cdev->gadget->dev,
 194                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 195         return 0;
 196 
 197 fail_otg_desc:
 198         kfree(otg_desc[0]);
 199         otg_desc[0] = NULL;
 200 fail_string_ids:
 201         fsg_common_remove_luns(opts->common);
 202 fail_set_cdev:
 203         fsg_common_free_buffers(opts->common);
 204 fail:
 205         usb_put_function_instance(fi_msg);
 206         return status;
 207 }
 208 
 209 static int msg_unbind(struct usb_composite_dev *cdev)
 210 {
 211         if (!IS_ERR(f_msg))
 212                 usb_put_function(f_msg);
 213 
 214         if (!IS_ERR(fi_msg))
 215                 usb_put_function_instance(fi_msg);
 216 
 217         kfree(otg_desc[0]);
 218         otg_desc[0] = NULL;
 219 
 220         return 0;
 221 }
 222 
 223 /****************************** Some noise ******************************/
 224 
 225 static struct usb_composite_driver msg_driver = {
 226         .name           = "g_mass_storage",
 227         .dev            = &msg_device_desc,
 228         .max_speed      = USB_SPEED_SUPER_PLUS,
 229         .needs_serial   = 1,
 230         .strings        = dev_strings,
 231         .bind           = msg_bind,
 232         .unbind         = msg_unbind,
 233 };
 234 
 235 MODULE_DESCRIPTION(DRIVER_DESC);
 236 MODULE_AUTHOR("Michal Nazarewicz");
 237 MODULE_LICENSE("GPL");
 238 
 239 static int __init msg_init(void)
 240 {
 241         return usb_composite_probe(&msg_driver);
 242 }
 243 module_init(msg_init);
 244 
 245 static void __exit msg_cleanup(void)
 246 {
 247         usb_composite_unregister(&msg_driver);
 248 }
 249 module_exit(msg_cleanup);