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 <m.nazarewicz@samsung.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/utsname.h>
  33 #include <linux/usb/ch9.h>
  34
  35
  36 /*-------------------------------------------------------------------------*/
  37
  38 #define DRIVER_DESC             "Mass Storage Gadget"
  39 #define DRIVER_VERSION          "2009/09/11"
  40
  41 /*-------------------------------------------------------------------------*/
  42
  43 /*
  44  * kbuild is not very cooperative with respect to linking separately
  45  * compiled library objects into one module.  So for now we won't use
  46  * separate compilation ... ensuring init/exit sections work to shrink
  47  * the runtime footprint, and giving us at least some parts of what
  48  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  49  */
  50
  51 #include "composite.c"
  52 #include "usbstring.c"
  53 #include "config.c"
  54 #include "epautoconf.c"
  55 #include "f_mass_storage.c"
  56
  57 /*-------------------------------------------------------------------------*/
  58
  59 static struct usb_device_descriptor msg_device_desc = {
  60         .bLength =              sizeof msg_device_desc,
  61         .bDescriptorType =      USB_DT_DEVICE,
  62
  63         .bcdUSB =               cpu_to_le16(0x0200),
  64         .bDeviceClass =         USB_CLASS_PER_INTERFACE,
  65
  66         /* Vendor and product id can be overridden by module parameters.  */
  67         .idVendor =             cpu_to_le16(FSG_VENDOR_ID),
  68         .idProduct =            cpu_to_le16(FSG_PRODUCT_ID),
  69         .bNumConfigurations =   1,
  70 };
  71
  72 static struct usb_otg_descriptor otg_descriptor = {
  73         .bLength =              sizeof otg_descriptor,
  74         .bDescriptorType =      USB_DT_OTG,
  75
  76         /*
  77          * REVISIT SRP-only hardware is possible, although
  78          * it would not be called "OTG" ...
  79          */
  80         .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
  81 };
  82
  83 static const struct usb_descriptor_header *otg_desc[] = {
  84         (struct usb_descriptor_header *) &otg_descriptor,
  85         NULL,
  86 };
  87
  88
  89 /****************************** Configurations ******************************/
  90
  91 static struct fsg_module_parameters mod_data = {
  92         .stall = 1
  93 };
  94 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
  95
  96 static unsigned long msg_registered;
  97 static void msg_cleanup(void);
  98
  99 static int msg_thread_exits(struct fsg_common *common)
 100 {
 101         msg_cleanup();
 102         return 0;
 103 }
 104
 105 static int __init msg_do_config(struct usb_configuration *c)
 106 {
 107         static const struct fsg_operations ops = {
 108                 .thread_exits = msg_thread_exits,
 109         };
 110         static struct fsg_common common;
 111
 112         struct fsg_common *retp;
 113         struct fsg_config config;
 114         int ret;
 115
 116         if (gadget_is_otg(c->cdev->gadget)) {
 117                 c->descriptors = otg_desc;
 118                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 119         }
 120
 121         fsg_config_from_params(&config, &mod_data);
 122         config.ops = &ops;
 123
 124         retp = fsg_common_init(&common, c->cdev, &config);
 125         if (IS_ERR(retp))
 126                 return PTR_ERR(retp);
 127
 128         ret = fsg_bind_config(c->cdev, c, &common);
 129         fsg_common_put(&common);
 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 __init msg_bind(struct usb_composite_dev *cdev)
 143 {
 144         int status;
 145
 146         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 147         if (status < 0)
 148                 return status;
 149
 150         dev_info(&cdev->gadget->dev,
 151                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 152         set_bit(0, &msg_registered);
 153         return 0;
 154 }
 155
 156
 157 /****************************** Some noise ******************************/
 158
 159 static struct usb_composite_driver msg_driver = {
 160         .name           = "g_mass_storage",
 161         .dev            = &msg_device_desc,
 162         .iProduct       = DRIVER_DESC,
 163         .max_speed      = USB_SPEED_HIGH,
 164         .needs_serial   = 1,
 165 };
 166
 167 MODULE_DESCRIPTION(DRIVER_DESC);
 168 MODULE_AUTHOR("Michal Nazarewicz");
 169 MODULE_LICENSE("GPL");
 170
 171 static int __init msg_init(void)
 172 {
 173         return usb_composite_probe(&msg_driver, msg_bind);
 174 }
 175 module_init(msg_init);
 176
 177 static void msg_cleanup(void)
 178 {
 179         if (test_and_clear_bit(0, &msg_registered))
 180                 usb_composite_unregister(&msg_driver);
 181 }
 182 module_exit(msg_cleanup);