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 int msg_do_config(struct usb_configuration *c)
 111 {
 112         struct fsg_opts *opts;
 113         int ret;
 114
 115         if (gadget_is_otg(c->cdev->gadget)) {
 116                 c->descriptors = otg_desc;
 117                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 118         }
 119
 120         opts = fsg_opts_from_func_inst(fi_msg);
 121
 122         f_msg = usb_get_function(fi_msg);
 123         if (IS_ERR(f_msg))
 124                 return PTR_ERR(f_msg);
 125
 126         ret = usb_add_function(c, f_msg);
 127         if (ret)
 128                 goto put_func;
 129
 130         return 0;
 131
 132 put_func:
 133         usb_put_function(f_msg);
 134         return ret;
 135 }
 136
 137 static struct usb_configuration msg_config_driver = {
 138         .label                  = "Linux File-Backed Storage",
 139         .bConfigurationValue    = 1,
 140         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 141 };
 142
 143
 144 /****************************** Gadget Bind ******************************/
 145
 146 static int msg_bind(struct usb_composite_dev *cdev)
 147 {
 148         struct fsg_opts *opts;
 149         struct fsg_config config;
 150         int status;
 151
 152         fi_msg = usb_get_function_instance("mass_storage");
 153         if (IS_ERR(fi_msg))
 154                 return PTR_ERR(fi_msg);
 155
 156         fsg_config_from_params(&config, &mod_data, fsg_num_buffers);
 157         opts = fsg_opts_from_func_inst(fi_msg);
 158
 159         opts->no_configfs = true;
 160         status = fsg_common_set_num_buffers(opts->common, fsg_num_buffers);
 161         if (status)
 162                 goto fail;
 163
 164         status = fsg_common_set_cdev(opts->common, cdev, config.can_stall);
 165         if (status)
 166                 goto fail_set_cdev;
 167
 168         fsg_common_set_sysfs(opts->common, true);
 169         status = fsg_common_create_luns(opts->common, &config);
 170         if (status)
 171                 goto fail_set_cdev;
 172
 173         fsg_common_set_inquiry_string(opts->common, config.vendor_name,
 174                                       config.product_name);
 175
 176         status = usb_string_ids_tab(cdev, strings_dev);
 177         if (status < 0)
 178                 goto fail_string_ids;
 179         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 180
 181         if (gadget_is_otg(cdev->gadget) && !otg_desc[0]) {
 182                 struct usb_descriptor_header *usb_desc;
 183
 184                 usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
 185                 if (!usb_desc)
 186                         goto fail_string_ids;
 187                 usb_otg_descriptor_init(cdev->gadget, usb_desc);
 188                 otg_desc[0] = usb_desc;
 189                 otg_desc[1] = NULL;
 190         }
 191
 192         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 193         if (status < 0)
 194                 goto fail_otg_desc;
 195
 196         usb_composite_overwrite_options(cdev, &coverwrite);
 197         dev_info(&cdev->gadget->dev,
 198                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 199         return 0;
 200
 201 fail_otg_desc:
 202         kfree(otg_desc[0]);
 203         otg_desc[0] = NULL;
 204 fail_string_ids:
 205         fsg_common_remove_luns(opts->common);
 206 fail_set_cdev:
 207         fsg_common_free_buffers(opts->common);
 208 fail:
 209         usb_put_function_instance(fi_msg);
 210         return status;
 211 }
 212
 213 static int msg_unbind(struct usb_composite_dev *cdev)
 214 {
 215         if (!IS_ERR(f_msg))
 216                 usb_put_function(f_msg);
 217
 218         if (!IS_ERR(fi_msg))
 219                 usb_put_function_instance(fi_msg);
 220
 221         kfree(otg_desc[0]);
 222         otg_desc[0] = NULL;
 223
 224         return 0;
 225 }
 226
 227 /****************************** Some noise ******************************/
 228
 229 static struct usb_composite_driver msg_driver = {
 230         .name           = "g_mass_storage",
 231         .dev            = &msg_device_desc,
 232         .max_speed      = USB_SPEED_SUPER,
 233         .needs_serial   = 1,
 234         .strings        = dev_strings,
 235         .bind           = msg_bind,
 236         .unbind         = msg_unbind,
 237 };
 238
 239 MODULE_DESCRIPTION(DRIVER_DESC);
 240 MODULE_AUTHOR("Michal Nazarewicz");
 241 MODULE_LICENSE("GPL");
 242
 243 static int __init msg_init(void)
 244 {
 245         return usb_composite_probe(&msg_driver);
 246 }
 247 module_init(msg_init);
 248
 249 static void __exit msg_cleanup(void)
 250 {
 251         usb_composite_unregister(&msg_driver);
 252 }
 253 module_exit(msg_cleanup);