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 /*-------------------------------------------------------------------------*/
  50
  51 /*
  52  * kbuild is not very cooperative with respect to linking separately
  53  * compiled library objects into one module.  So for now we won't use
  54  * separate compilation ... ensuring init/exit sections work to shrink
  55  * the runtime footprint, and giving us at least some parts of what
  56  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  57  */
  58 #include "f_mass_storage.c"
  59
  60 /*-------------------------------------------------------------------------*/
  61 USB_GADGET_COMPOSITE_OPTIONS();
  62
  63 static struct usb_device_descriptor msg_device_desc = {
  64         .bLength =              sizeof msg_device_desc,
  65         .bDescriptorType =      USB_DT_DEVICE,
  66
  67         .bcdUSB =               cpu_to_le16(0x0200),
  68         .bDeviceClass =         USB_CLASS_PER_INTERFACE,
  69
  70         /* Vendor and product id can be overridden by module parameters.  */
  71         .idVendor =             cpu_to_le16(FSG_VENDOR_ID),
  72         .idProduct =            cpu_to_le16(FSG_PRODUCT_ID),
  73         .bNumConfigurations =   1,
  74 };
  75
  76 static struct usb_otg_descriptor otg_descriptor = {
  77         .bLength =              sizeof otg_descriptor,
  78         .bDescriptorType =      USB_DT_OTG,
  79
  80         /*
  81          * REVISIT SRP-only hardware is possible, although
  82          * it would not be called "OTG" ...
  83          */
  84         .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
  85 };
  86
  87 static const struct usb_descriptor_header *otg_desc[] = {
  88         (struct usb_descriptor_header *) &otg_descriptor,
  89         NULL,
  90 };
  91
  92 static struct usb_string strings_dev[] = {
  93         [USB_GADGET_MANUFACTURER_IDX].s = "",
  94         [USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
  95         [USB_GADGET_SERIAL_IDX].s = "",
  96         {  } /* end of list */
  97 };
  98
  99 static struct usb_gadget_strings stringtab_dev = {
 100         .language       = 0x0409,       /* en-us */
 101         .strings        = strings_dev,
 102 };
 103
 104 static struct usb_gadget_strings *dev_strings[] = {
 105         &stringtab_dev,
 106         NULL,
 107 };
 108
 109 /****************************** Configurations ******************************/
 110
 111 static struct fsg_module_parameters mod_data = {
 112         .stall = 1
 113 };
 114 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
 115
 116 static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
 117
 118 #else
 119
 120 /*
 121  * Number of buffers we will use.
 122  * 2 is usually enough for good buffering pipeline
 123  */
 124 #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
 125
 126 #endif /* CONFIG_USB_GADGET_DEBUG_FILES */
 127
 128 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 129
 130 static unsigned long msg_registered;
 131 static void msg_cleanup(void);
 132
 133 static int msg_thread_exits(struct fsg_common *common)
 134 {
 135         msg_cleanup();
 136         return 0;
 137 }
 138
 139 static int __init msg_do_config(struct usb_configuration *c)
 140 {
 141         static const struct fsg_operations ops = {
 142                 .thread_exits = msg_thread_exits,
 143         };
 144         static struct fsg_common common;
 145
 146         struct fsg_common *retp;
 147         struct fsg_config config;
 148         int ret;
 149
 150         if (gadget_is_otg(c->cdev->gadget)) {
 151                 c->descriptors = otg_desc;
 152                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 153         }
 154
 155         fsg_config_from_params(&config, &mod_data, fsg_num_buffers);
 156         config.ops = &ops;
 157
 158         retp = fsg_common_init(&common, c->cdev, &config);
 159         if (IS_ERR(retp))
 160                 return PTR_ERR(retp);
 161
 162         ret = fsg_bind_config(c->cdev, c, &common);
 163         fsg_common_put(&common);
 164         return ret;
 165 }
 166
 167 static struct usb_configuration msg_config_driver = {
 168         .label                  = "Linux File-Backed Storage",
 169         .bConfigurationValue    = 1,
 170         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 171 };
 172
 173
 174 /****************************** Gadget Bind ******************************/
 175
 176 static int __init msg_bind(struct usb_composite_dev *cdev)
 177 {
 178         int status;
 179
 180         status = usb_string_ids_tab(cdev, strings_dev);
 181         if (status < 0)
 182                 return status;
 183         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 184
 185         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 186         if (status < 0)
 187                 return status;
 188         usb_composite_overwrite_options(cdev, &coverwrite);
 189         dev_info(&cdev->gadget->dev,
 190                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 191         set_bit(0, &msg_registered);
 192         return 0;
 193 }
 194
 195
 196 /****************************** Some noise ******************************/
 197
 198 static __refdata struct usb_composite_driver msg_driver = {
 199         .name           = "g_mass_storage",
 200         .dev            = &msg_device_desc,
 201         .max_speed      = USB_SPEED_SUPER,
 202         .needs_serial   = 1,
 203         .strings        = dev_strings,
 204         .bind           = msg_bind,
 205 };
 206
 207 MODULE_DESCRIPTION(DRIVER_DESC);
 208 MODULE_AUTHOR("Michal Nazarewicz");
 209 MODULE_LICENSE("GPL");
 210
 211 static int __init msg_init(void)
 212 {
 213         return usb_composite_probe(&msg_driver);
 214 }
 215 module_init(msg_init);
 216
 217 static void msg_cleanup(void)
 218 {
 219         if (test_and_clear_bit(0, &msg_registered))
 220                 usb_composite_unregister(&msg_driver);
 221 }
 222 module_exit(msg_cleanup);