drivers/usb/gadget/mass_storage.c

   1 /*
   2  * mass_storage.c -- Mass Storage USB Gadget
   3  *
   4  * Copyright (C) 2003-2008 Alan Stern
   5  * Copyright (C) 2009 Samsung Electronics
   6  *                    Author: Michal Nazarewicz <mina86@mina86.com>
   7  * All rights reserved.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  */
  14
  15
  16 /*
  17  * The Mass Storage Gadget acts as a USB Mass Storage device,
  18  * appearing to the host as a disk drive or as a CD-ROM drive.  In
  19  * addition to providing an example of a genuinely useful gadget
  20  * driver for a USB device, it also illustrates a technique of
  21  * double-buffering for increased throughput.  Last but not least, it
  22  * gives an easy way to probe the behavior of the Mass Storage drivers
  23  * in a USB host.
  24  *
  25  * Since this file serves only administrative purposes and all the
  26  * business logic is implemented in f_mass_storage.* file.  Read
  27  * comments in this file for more detailed description.
  28  */
  29
  30
  31 #include <linux/kernel.h>
  32 #include <linux/usb/ch9.h>
  33 #include <linux/module.h>
  34
  35 /*-------------------------------------------------------------------------*/
  36
  37 #define DRIVER_DESC             "Mass Storage Gadget"
  38 #define DRIVER_VERSION          "2009/09/11"
  39
  40 /*
  41  * Thanks to NetChip Technologies for donating this product ID.
  42  *
  43  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  44  * Instead:  allocate your own, using normal USB-IF procedures.
  45  */
  46 #define FSG_VENDOR_ID   0x0525  /* NetChip */
  47 #define FSG_PRODUCT_ID  0xa4a5  /* Linux-USB File-backed Storage Gadget */
  48
  49 #include "f_mass_storage.h"
  50
  51 /*-------------------------------------------------------------------------*/
  52 USB_GADGET_COMPOSITE_OPTIONS();
  53
  54 static struct usb_device_descriptor msg_device_desc = {
  55         .bLength =              sizeof msg_device_desc,
  56         .bDescriptorType =      USB_DT_DEVICE,
  57
  58         .bcdUSB =               cpu_to_le16(0x0200),
  59         .bDeviceClass =         USB_CLASS_PER_INTERFACE,
  60
  61         /* Vendor and product id can be overridden by module parameters.  */
  62         .idVendor =             cpu_to_le16(FSG_VENDOR_ID),
  63         .idProduct =            cpu_to_le16(FSG_PRODUCT_ID),
  64         .bNumConfigurations =   1,
  65 };
  66
  67 static struct usb_otg_descriptor otg_descriptor = {
  68         .bLength =              sizeof otg_descriptor,
  69         .bDescriptorType =      USB_DT_OTG,
  70
  71         /*
  72          * REVISIT SRP-only hardware is possible, although
  73          * it would not be called "OTG" ...
  74          */
  75         .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
  76 };
  77
  78 static const struct usb_descriptor_header *otg_desc[] = {
  79         (struct usb_descriptor_header *) &otg_descriptor,
  80         NULL,
  81 };
  82
  83 static struct usb_string strings_dev[] = {
  84         [USB_GADGET_MANUFACTURER_IDX].s = "",
  85         [USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
  86         [USB_GADGET_SERIAL_IDX].s = "",
  87         {  } /* end of list */
  88 };
  89
  90 static struct usb_gadget_strings stringtab_dev = {
  91         .language       = 0x0409,       /* en-us */
  92         .strings        = strings_dev,
  93 };
  94
  95 static struct usb_gadget_strings *dev_strings[] = {
  96         &stringtab_dev,
  97         NULL,
  98 };
  99
 100 static struct usb_function_instance *fi_msg;
 101 static struct usb_function *f_msg;
 102
 103 /****************************** Configurations ******************************/
 104
 105 static struct fsg_module_parameters mod_data = {
 106         .stall = 1
 107 };
 108 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
 109
 110 static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
 111
 112 #else
 113
 114 /*
 115  * Number of buffers we will use.
 116  * 2 is usually enough for good buffering pipeline
 117  */
 118 #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
 119
 120 #endif /* CONFIG_USB_GADGET_DEBUG_FILES */
 121
 122 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 123
 124 static unsigned long msg_registered;
 125 static void msg_cleanup(void);
 126
 127 static int msg_thread_exits(struct fsg_common *common)
 128 {
 129         msg_cleanup();
 130         return 0;
 131 }
 132
 133 static int __init msg_do_config(struct usb_configuration *c)
 134 {
 135         struct fsg_opts *opts;
 136         int ret;
 137
 138         if (gadget_is_otg(c->cdev->gadget)) {
 139                 c->descriptors = otg_desc;
 140                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 141         }
 142
 143         opts = fsg_opts_from_func_inst(fi_msg);
 144
 145         f_msg = usb_get_function(fi_msg);
 146         if (IS_ERR(f_msg))
 147                 return PTR_ERR(f_msg);
 148
 149         ret = fsg_common_run_thread(opts->common);
 150         if (ret)
 151                 goto put_func;
 152
 153         ret = usb_add_function(c, f_msg);
 154         if (ret)
 155                 goto put_func;
 156
 157         return 0;
 158
 159 put_func:
 160         usb_put_function(f_msg);
 161         return ret;
 162 }
 163
 164 static struct usb_configuration msg_config_driver = {
 165         .label                  = "Linux File-Backed Storage",
 166         .bConfigurationValue    = 1,
 167         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 168 };
 169
 170
 171 /****************************** Gadget Bind ******************************/
 172
 173 static int __init msg_bind(struct usb_composite_dev *cdev)
 174 {
 175         static const struct fsg_operations ops = {
 176                 .thread_exits = msg_thread_exits,
 177         };
 178         struct fsg_opts *opts;
 179         struct fsg_config config;
 180         int status;
 181
 182         fi_msg = usb_get_function_instance("mass_storage");
 183         if (IS_ERR(fi_msg))
 184                 return PTR_ERR(fi_msg);
 185
 186         fsg_config_from_params(&config, &mod_data, fsg_num_buffers);
 187         opts = fsg_opts_from_func_inst(fi_msg);
 188
 189         opts->no_configfs = true;
 190         status = fsg_common_set_num_buffers(opts->common, fsg_num_buffers);
 191         if (status)
 192                 goto fail;
 193
 194         status = fsg_common_set_nluns(opts->common, config.nluns);
 195         if (status)
 196                 goto fail_set_nluns;
 197
 198         fsg_common_set_ops(opts->common, &ops);
 199
 200         status = fsg_common_set_cdev(opts->common, cdev, config.can_stall);
 201         if (status)
 202                 goto fail_set_cdev;
 203
 204         fsg_common_set_sysfs(opts->common, true);
 205         status = fsg_common_create_luns(opts->common, &config);
 206         if (status)
 207                 goto fail_set_cdev;
 208
 209         fsg_common_set_inquiry_string(opts->common, config.vendor_name,
 210                                       config.product_name);
 211
 212         status = usb_string_ids_tab(cdev, strings_dev);
 213         if (status < 0)
 214                 goto fail_string_ids;
 215         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 216
 217         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 218         if (status < 0)
 219                 goto fail_string_ids;
 220
 221         usb_composite_overwrite_options(cdev, &coverwrite);
 222         dev_info(&cdev->gadget->dev,
 223                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 224         set_bit(0, &msg_registered);
 225         return 0;
 226
 227 fail_string_ids:
 228         fsg_common_remove_luns(opts->common);
 229 fail_set_cdev:
 230         fsg_common_free_luns(opts->common);
 231 fail_set_nluns:
 232         fsg_common_free_buffers(opts->common);
 233 fail:
 234         usb_put_function_instance(fi_msg);
 235         return status;
 236 }
 237
 238 static int msg_unbind(struct usb_composite_dev *cdev)
 239 {
 240         if (!IS_ERR(f_msg))
 241                 usb_put_function(f_msg);
 242
 243         if (!IS_ERR(fi_msg))
 244                 usb_put_function_instance(fi_msg);
 245
 246         return 0;
 247 }
 248
 249 /****************************** Some noise ******************************/
 250
 251 static __refdata struct usb_composite_driver msg_driver = {
 252         .name           = "g_mass_storage",
 253         .dev            = &msg_device_desc,
 254         .max_speed      = USB_SPEED_SUPER,
 255         .needs_serial   = 1,
 256         .strings        = dev_strings,
 257         .bind           = msg_bind,
 258         .unbind         = msg_unbind,
 259 };
 260
 261 MODULE_DESCRIPTION(DRIVER_DESC);
 262 MODULE_AUTHOR("Michal Nazarewicz");
 263 MODULE_LICENSE("GPL");
 264
 265 static int __init msg_init(void)
 266 {
 267         return usb_composite_probe(&msg_driver);
 268 }
 269 module_init(msg_init);
 270
 271 static void msg_cleanup(void)
 272 {
 273         if (test_and_clear_bit(0, &msg_registered))
 274                 usb_composite_unregister(&msg_driver);
 275 }
 276 module_exit(msg_cleanup);