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  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24
  25 /*
  26  * The Mass Storage Gadget acts as a USB Mass Storage device,
  27  * appearing to the host as a disk drive or as a CD-ROM drive.  In
  28  * addition to providing an example of a genuinely useful gadget
  29  * driver for a USB device, it also illustrates a technique of
  30  * double-buffering for increased throughput.  Last but not least, it
  31  * gives an easy way to probe the behavior of the Mass Storage drivers
  32  * in a USB host.
  33  *
  34  * Since this file serves only administrative purposes and all the
  35  * business logic is implemented in f_mass_storage.* file.  Read
  36  * comments in this file for more detailed description.
  37  */
  38
  39
  40 #include <linux/kernel.h>
  41 #include <linux/utsname.h>
  42 #include <linux/usb/ch9.h>
  43
  44
  45 /*-------------------------------------------------------------------------*/
  46
  47 #define DRIVER_DESC             "Mass Storage Gadget"
  48 #define DRIVER_VERSION          "2009/09/11"
  49
  50 /*-------------------------------------------------------------------------*/
  51
  52 /*
  53  * kbuild is not very cooperative with respect to linking separately
  54  * compiled library objects into one module.  So for now we won't use
  55  * separate compilation ... ensuring init/exit sections work to shrink
  56  * the runtime footprint, and giving us at least some parts of what
  57  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  58  */
  59
  60 #include "composite.c"
  61 #include "usbstring.c"
  62 #include "config.c"
  63 #include "epautoconf.c"
  64 #include "f_mass_storage.c"
  65
  66 /*-------------------------------------------------------------------------*/
  67
  68 static struct usb_device_descriptor msg_device_desc = {
  69         .bLength =              sizeof msg_device_desc,
  70         .bDescriptorType =      USB_DT_DEVICE,
  71
  72         .bcdUSB =               cpu_to_le16(0x0200),
  73         .bDeviceClass =         USB_CLASS_PER_INTERFACE,
  74
  75         /* Vendor and product id can be overridden by module parameters.  */
  76         .idVendor =             cpu_to_le16(FSG_VENDOR_ID),
  77         .idProduct =            cpu_to_le16(FSG_PRODUCT_ID),
  78         .bNumConfigurations =   1,
  79 };
  80
  81 static struct usb_otg_descriptor otg_descriptor = {
  82         .bLength =              sizeof otg_descriptor,
  83         .bDescriptorType =      USB_DT_OTG,
  84
  85         /*
  86          * REVISIT SRP-only hardware is possible, although
  87          * it would not be called "OTG" ...
  88          */
  89         .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
  90 };
  91
  92 static const struct usb_descriptor_header *otg_desc[] = {
  93         (struct usb_descriptor_header *) &otg_descriptor,
  94         NULL,
  95 };
  96
  97
  98 /****************************** Configurations ******************************/
  99
 100 static struct fsg_module_parameters mod_data = {
 101         .stall = 1
 102 };
 103 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 104
 105 static unsigned long msg_registered;
 106 static void msg_cleanup(void);
 107
 108 static int msg_thread_exits(struct fsg_common *common)
 109 {
 110         msg_cleanup();
 111         return 0;
 112 }
 113
 114 static int __init msg_do_config(struct usb_configuration *c)
 115 {
 116         static const struct fsg_operations ops = {
 117                 .thread_exits = msg_thread_exits,
 118         };
 119         static struct fsg_common common;
 120
 121         struct fsg_common *retp;
 122         struct fsg_config config;
 123         int ret;
 124
 125         if (gadget_is_otg(c->cdev->gadget)) {
 126                 c->descriptors = otg_desc;
 127                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 128         }
 129
 130         fsg_config_from_params(&config, &mod_data);
 131         config.ops = &ops;
 132
 133         retp = fsg_common_init(&common, c->cdev, &config);
 134         if (IS_ERR(retp))
 135                 return PTR_ERR(retp);
 136
 137         ret = fsg_bind_config(c->cdev, c, &common);
 138         fsg_common_put(&common);
 139         return ret;
 140 }
 141
 142 static struct usb_configuration msg_config_driver = {
 143         .label                  = "Linux File-Backed Storage",
 144         .bConfigurationValue    = 1,
 145         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 146 };
 147
 148
 149 /****************************** Gadget Bind ******************************/
 150
 151 static int __init msg_bind(struct usb_composite_dev *cdev)
 152 {
 153         int status;
 154
 155         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 156         if (status < 0)
 157                 return status;
 158
 159         dev_info(&cdev->gadget->dev,
 160                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 161         set_bit(0, &msg_registered);
 162         return 0;
 163 }
 164
 165
 166 /****************************** Some noise ******************************/
 167
 168 static struct usb_composite_driver msg_driver = {
 169         .name           = "g_mass_storage",
 170         .dev            = &msg_device_desc,
 171         .iProduct       = DRIVER_DESC,
 172         .needs_serial   = 1,
 173 };
 174
 175 MODULE_DESCRIPTION(DRIVER_DESC);
 176 MODULE_AUTHOR("Michal Nazarewicz");
 177 MODULE_LICENSE("GPL");
 178
 179 static int __init msg_init(void)
 180 {
 181         return usb_composite_probe(&msg_driver, msg_bind);
 182 }
 183 module_init(msg_init);
 184
 185 static void msg_cleanup(void)
 186 {
 187         if (test_and_clear_bit(0, &msg_registered))
 188                 usb_composite_unregister(&msg_driver);
 189 }
 190 module_exit(msg_cleanup);