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
  42 /*
  43  * kbuild is not very cooperative with respect to linking separately
  44  * compiled library objects into one module.  So for now we won't use
  45  * separate compilation ... ensuring init/exit sections work to shrink
  46  * the runtime footprint, and giving us at least some parts of what
  47  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  48  */
  49 #include "f_mass_storage.c"
  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 /****************************** Configurations ******************************/
 101
 102 static struct fsg_module_parameters mod_data = {
 103         .stall = 1
 104 };
 105 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 106
 107 static unsigned long msg_registered;
 108 static void msg_cleanup(void);
 109
 110 static int msg_thread_exits(struct fsg_common *common)
 111 {
 112         msg_cleanup();
 113         return 0;
 114 }
 115
 116 static int __init msg_do_config(struct usb_configuration *c)
 117 {
 118         static const struct fsg_operations ops = {
 119                 .thread_exits = msg_thread_exits,
 120         };
 121         static struct fsg_common common;
 122
 123         struct fsg_common *retp;
 124         struct fsg_config config;
 125         int ret;
 126
 127         if (gadget_is_otg(c->cdev->gadget)) {
 128                 c->descriptors = otg_desc;
 129                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 130         }
 131
 132         fsg_config_from_params(&config, &mod_data);
 133         config.ops = &ops;
 134
 135         retp = fsg_common_init(&common, c->cdev, &config);
 136         if (IS_ERR(retp))
 137                 return PTR_ERR(retp);
 138
 139         ret = fsg_bind_config(c->cdev, c, &common);
 140         fsg_common_put(&common);
 141         return ret;
 142 }
 143
 144 static struct usb_configuration msg_config_driver = {
 145         .label                  = "Linux File-Backed Storage",
 146         .bConfigurationValue    = 1,
 147         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 148 };
 149
 150
 151 /****************************** Gadget Bind ******************************/
 152
 153 static int __init msg_bind(struct usb_composite_dev *cdev)
 154 {
 155         int status;
 156
 157         status = usb_string_ids_tab(cdev, strings_dev);
 158         if (status < 0)
 159                 return status;
 160         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 161
 162         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 163         if (status < 0)
 164                 return status;
 165         usb_composite_overwrite_options(cdev, &coverwrite);
 166         dev_info(&cdev->gadget->dev,
 167                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 168         set_bit(0, &msg_registered);
 169         return 0;
 170 }
 171
 172
 173 /****************************** Some noise ******************************/
 174
 175 static __refdata struct usb_composite_driver msg_driver = {
 176         .name           = "g_mass_storage",
 177         .dev            = &msg_device_desc,
 178         .max_speed      = USB_SPEED_SUPER,
 179         .needs_serial   = 1,
 180         .strings        = dev_strings,
 181         .bind           = msg_bind,
 182 };
 183
 184 MODULE_DESCRIPTION(DRIVER_DESC);
 185 MODULE_AUTHOR("Michal Nazarewicz");
 186 MODULE_LICENSE("GPL");
 187
 188 static int __init msg_init(void)
 189 {
 190         return usb_composite_probe(&msg_driver);
 191 }
 192 module_init(msg_init);
 193
 194 static void msg_cleanup(void)
 195 {
 196         if (test_and_clear_bit(0, &msg_registered))
 197                 usb_composite_unregister(&msg_driver);
 198 }
 199 module_exit(msg_cleanup);