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 = DYNAMIC */
  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 = fsg_common_run_thread(opts->common);
 136         if (ret)
 137                 goto put_func;
 138
 139         ret = usb_add_function(c, f_msg);
 140         if (ret)
 141                 goto put_func;
 142
 143         return 0;
 144
 145 put_func:
 146         usb_put_function(f_msg);
 147         return ret;
 148 }
 149
 150 static struct usb_configuration msg_config_driver = {
 151         .label                  = "Linux File-Backed Storage",
 152         .bConfigurationValue    = 1,
 153         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 154 };
 155
 156
 157 /****************************** Gadget Bind ******************************/
 158
 159 static int msg_bind(struct usb_composite_dev *cdev)
 160 {
 161         static const struct fsg_operations ops = {
 162                 .thread_exits = msg_thread_exits,
 163         };
 164         struct fsg_opts *opts;
 165         struct fsg_config config;
 166         int status;
 167
 168         fi_msg = usb_get_function_instance("mass_storage");
 169         if (IS_ERR(fi_msg))
 170                 return PTR_ERR(fi_msg);
 171
 172         fsg_config_from_params(&config, &mod_data, fsg_num_buffers);
 173         opts = fsg_opts_from_func_inst(fi_msg);
 174
 175         opts->no_configfs = true;
 176         status = fsg_common_set_num_buffers(opts->common, fsg_num_buffers);
 177         if (status)
 178                 goto fail;
 179
 180         fsg_common_set_ops(opts->common, &ops);
 181
 182         status = fsg_common_set_cdev(opts->common, cdev, config.can_stall);
 183         if (status)
 184                 goto fail_set_cdev;
 185
 186         fsg_common_set_sysfs(opts->common, true);
 187         status = fsg_common_create_luns(opts->common, &config);
 188         if (status)
 189                 goto fail_set_cdev;
 190
 191         fsg_common_set_inquiry_string(opts->common, config.vendor_name,
 192                                       config.product_name);
 193
 194         status = usb_string_ids_tab(cdev, strings_dev);
 195         if (status < 0)
 196                 goto fail_string_ids;
 197         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 198
 199         if (gadget_is_otg(cdev->gadget) && !otg_desc[0]) {
 200                 struct usb_descriptor_header *usb_desc;
 201
 202                 usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
 203                 if (!usb_desc)
 204                         goto fail_string_ids;
 205                 usb_otg_descriptor_init(cdev->gadget, usb_desc);
 206                 otg_desc[0] = usb_desc;
 207                 otg_desc[1] = NULL;
 208         }
 209
 210         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 211         if (status < 0)
 212                 goto fail_otg_desc;
 213
 214         usb_composite_overwrite_options(cdev, &coverwrite);
 215         dev_info(&cdev->gadget->dev,
 216                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 217         set_bit(0, &msg_registered);
 218         return 0;
 219
 220 fail_otg_desc:
 221         kfree(otg_desc[0]);
 222         otg_desc[0] = NULL;
 223 fail_string_ids:
 224         fsg_common_remove_luns(opts->common);
 225 fail_set_cdev:
 226         fsg_common_free_buffers(opts->common);
 227 fail:
 228         usb_put_function_instance(fi_msg);
 229         return status;
 230 }
 231
 232 static int msg_unbind(struct usb_composite_dev *cdev)
 233 {
 234         if (!IS_ERR(f_msg))
 235                 usb_put_function(f_msg);
 236
 237         if (!IS_ERR(fi_msg))
 238                 usb_put_function_instance(fi_msg);
 239
 240         kfree(otg_desc[0]);
 241         otg_desc[0] = NULL;
 242
 243         return 0;
 244 }
 245
 246 /****************************** Some noise ******************************/
 247
 248 static struct usb_composite_driver msg_driver = {
 249         .name           = "g_mass_storage",
 250         .dev            = &msg_device_desc,
 251         .max_speed      = USB_SPEED_SUPER,
 252         .needs_serial   = 1,
 253         .strings        = dev_strings,
 254         .bind           = msg_bind,
 255         .unbind         = msg_unbind,
 256 };
 257
 258 MODULE_DESCRIPTION(DRIVER_DESC);
 259 MODULE_AUTHOR("Michal Nazarewicz");
 260 MODULE_LICENSE("GPL");
 261
 262 static int __init msg_init(void)
 263 {
 264         return usb_composite_probe(&msg_driver);
 265 }
 266 module_init(msg_init);
 267
 268 static void msg_cleanup(void)
 269 {
 270         if (test_and_clear_bit(0, &msg_registered))
 271                 usb_composite_unregister(&msg_driver);
 272 }
 273 module_exit(msg_cleanup);