kernel/drivers/usb/gadget/legacy/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 const struct usb_descriptor_header *otg_desc[2];
  68
  69 static struct usb_string strings_dev[] = {
  70         [USB_GADGET_MANUFACTURER_IDX].s = "",
  71         [USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
  72         [USB_GADGET_SERIAL_IDX].s = "",
  73         {  } /* end of list */
  74 };
  75
  76 static struct usb_gadget_strings stringtab_dev = {
  77         .language       = 0x0409,       /* en-us */
  78         .strings        = strings_dev,
  79 };
  80
  81 static struct usb_gadget_strings *dev_strings[] = {
  82         &stringtab_dev,
  83         NULL,
  84 };
  85
  86 static struct usb_function_instance *fi_msg;
  87 static struct usb_function *f_msg;
  88
  89 /****************************** Configurations ******************************/
  90
  91 static struct fsg_module_parameters mod_data = {
  92         .stall = 1
  93 };
  94 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
  95
  96 static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
  97
  98 #else
  99
 100 /*
 101  * Number of buffers we will use.
 102  * 2 is usually enough for good buffering pipeline
 103  */
 104 #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
 105
 106 #endif /* CONFIG_USB_GADGET_DEBUG_FILES */
 107
 108 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 109
 110 static unsigned long msg_registered;
 111 static void msg_cleanup(void);
 112
 113 static int msg_thread_exits(struct fsg_common *common)
 114 {
 115         msg_cleanup();
 116         return 0;
 117 }
 118
 119 static int msg_do_config(struct usb_configuration *c)
 120 {
 121         struct fsg_opts *opts;
 122         int ret;
 123
 124         if (gadget_is_otg(c->cdev->gadget)) {
 125                 c->descriptors = otg_desc;
 126                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 127         }
 128
 129         opts = fsg_opts_from_func_inst(fi_msg);
 130
 131         f_msg = usb_get_function(fi_msg);
 132         if (IS_ERR(f_msg))
 133                 return PTR_ERR(f_msg);
 134
 135         ret = usb_add_function(c, f_msg);
 136         if (ret)
 137                 goto put_func;
 138
 139         return 0;
 140
 141 put_func:
 142         usb_put_function(f_msg);
 143         return ret;
 144 }
 145
 146 static struct usb_configuration msg_config_driver = {
 147         .label                  = "Linux File-Backed Storage",
 148         .bConfigurationValue    = 1,
 149         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 150 };
 151
 152
 153 /****************************** Gadget Bind ******************************/
 154
 155 static int msg_bind(struct usb_composite_dev *cdev)
 156 {
 157         static const struct fsg_operations ops = {
 158                 .thread_exits = msg_thread_exits,
 159         };
 160         struct fsg_opts *opts;
 161         struct fsg_config config;
 162         int status;
 163
 164         fi_msg = usb_get_function_instance("mass_storage");
 165         if (IS_ERR(fi_msg))
 166                 return PTR_ERR(fi_msg);
 167
 168         fsg_config_from_params(&config, &mod_data, fsg_num_buffers);
 169         opts = fsg_opts_from_func_inst(fi_msg);
 170
 171         opts->no_configfs = true;
 172         status = fsg_common_set_num_buffers(opts->common, fsg_num_buffers);
 173         if (status)
 174                 goto fail;
 175
 176         fsg_common_set_ops(opts->common, &ops);
 177
 178         status = fsg_common_set_cdev(opts->common, cdev, config.can_stall);
 179         if (status)
 180                 goto fail_set_cdev;
 181
 182         fsg_common_set_sysfs(opts->common, true);
 183         status = fsg_common_create_luns(opts->common, &config);
 184         if (status)
 185                 goto fail_set_cdev;
 186
 187         fsg_common_set_inquiry_string(opts->common, config.vendor_name,
 188                                       config.product_name);
 189
 190         status = usb_string_ids_tab(cdev, strings_dev);
 191         if (status < 0)
 192                 goto fail_string_ids;
 193         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 194
 195         if (gadget_is_otg(cdev->gadget) && !otg_desc[0]) {
 196                 struct usb_descriptor_header *usb_desc;
 197
 198                 usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
 199                 if (!usb_desc)
 200                         goto fail_string_ids;
 201                 usb_otg_descriptor_init(cdev->gadget, usb_desc);
 202                 otg_desc[0] = usb_desc;
 203                 otg_desc[1] = NULL;
 204         }
 205
 206         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 207         if (status < 0)
 208                 goto fail_otg_desc;
 209
 210         usb_composite_overwrite_options(cdev, &coverwrite);
 211         dev_info(&cdev->gadget->dev,
 212                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 213         set_bit(0, &msg_registered);
 214         return 0;
 215
 216 fail_otg_desc:
 217         kfree(otg_desc[0]);
 218         otg_desc[0] = NULL;
 219 fail_string_ids:
 220         fsg_common_remove_luns(opts->common);
 221 fail_set_cdev:
 222         fsg_common_free_buffers(opts->common);
 223 fail:
 224         usb_put_function_instance(fi_msg);
 225         return status;
 226 }
 227
 228 static int msg_unbind(struct usb_composite_dev *cdev)
 229 {
 230         if (!IS_ERR(f_msg))
 231                 usb_put_function(f_msg);
 232
 233         if (!IS_ERR(fi_msg))
 234                 usb_put_function_instance(fi_msg);
 235
 236         kfree(otg_desc[0]);
 237         otg_desc[0] = NULL;
 238
 239         return 0;
 240 }
 241
 242 /****************************** Some noise ******************************/
 243
 244 static struct usb_composite_driver msg_driver = {
 245         .name           = "g_mass_storage",
 246         .dev            = &msg_device_desc,
 247         .max_speed      = USB_SPEED_SUPER,
 248         .needs_serial   = 1,
 249         .strings        = dev_strings,
 250         .bind           = msg_bind,
 251         .unbind         = msg_unbind,
 252 };
 253
 254 MODULE_DESCRIPTION(DRIVER_DESC);
 255 MODULE_AUTHOR("Michal Nazarewicz");
 256 MODULE_LICENSE("GPL");
 257
 258 static int __init msg_init(void)
 259 {
 260         return usb_composite_probe(&msg_driver);
 261 }
 262 module_init(msg_init);
 263
 264 static void msg_cleanup(void)
 265 {
 266         if (test_and_clear_bit(0, &msg_registered))
 267                 usb_composite_unregister(&msg_driver);
 268 }
 269 module_exit(msg_cleanup);