drivers/usb/gadget/legacy/mass_storage.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * mass_storage.c -- Mass Storage USB Gadget
   4  *
   5  * Copyright (C) 2003-2008 Alan Stern
   6  * Copyright (C) 2009 Samsung Electronics
   7  *                    Author: Michal Nazarewicz <mina86@mina86.com>
   8  * All rights reserved.
   9  */
  10
  11
  12 /*
  13  * The Mass Storage Gadget acts as a USB Mass Storage device,
  14  * appearing to the host as a disk drive or as a CD-ROM drive.  In
  15  * addition to providing an example of a genuinely useful gadget
  16  * driver for a USB device, it also illustrates a technique of
  17  * double-buffering for increased throughput.  Last but not least, it
  18  * gives an easy way to probe the behavior of the Mass Storage drivers
  19  * in a USB host.
  20  *
  21  * Since this file serves only administrative purposes and all the
  22  * business logic is implemented in f_mass_storage.* file.  Read
  23  * comments in this file for more detailed description.
  24  */
  25
  26
  27 #include <linux/kernel.h>
  28 #include <linux/usb/ch9.h>
  29 #include <linux/module.h>
  30
  31 /*-------------------------------------------------------------------------*/
  32
  33 #define DRIVER_DESC             "Mass Storage Gadget"
  34 #define DRIVER_VERSION          "2009/09/11"
  35
  36 /*
  37  * Thanks to NetChip Technologies for donating this product ID.
  38  *
  39  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  40  * Instead:  allocate your own, using normal USB-IF procedures.
  41  */
  42 #define FSG_VENDOR_ID   0x0525  /* NetChip */
  43 #define FSG_PRODUCT_ID  0xa4a5  /* Linux-USB File-backed Storage Gadget */
  44
  45 #include "f_mass_storage.h"
  46
  47 /*-------------------------------------------------------------------------*/
  48 USB_GADGET_COMPOSITE_OPTIONS();
  49
  50 static struct usb_device_descriptor msg_device_desc = {
  51         .bLength =              sizeof msg_device_desc,
  52         .bDescriptorType =      USB_DT_DEVICE,
  53
  54         /* .bcdUSB = DYNAMIC */
  55         .bDeviceClass =         USB_CLASS_PER_INTERFACE,
  56
  57         /* Vendor and product id can be overridden by module parameters.  */
  58         .idVendor =             cpu_to_le16(FSG_VENDOR_ID),
  59         .idProduct =            cpu_to_le16(FSG_PRODUCT_ID),
  60         .bNumConfigurations =   1,
  61 };
  62
  63 static const struct usb_descriptor_header *otg_desc[2];
  64
  65 static struct usb_string strings_dev[] = {
  66         [USB_GADGET_MANUFACTURER_IDX].s = "",
  67         [USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
  68         [USB_GADGET_SERIAL_IDX].s = "",
  69         {  } /* end of list */
  70 };
  71
  72 static struct usb_gadget_strings stringtab_dev = {
  73         .language       = 0x0409,       /* en-us */
  74         .strings        = strings_dev,
  75 };
  76
  77 static struct usb_gadget_strings *dev_strings[] = {
  78         &stringtab_dev,
  79         NULL,
  80 };
  81
  82 static struct usb_function_instance *fi_msg;
  83 static struct usb_function *f_msg;
  84
  85 /****************************** Configurations ******************************/
  86
  87 static struct fsg_module_parameters mod_data = {
  88         .stall = 1
  89 };
  90 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
  91
  92 static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
  93
  94 #else
  95
  96 /*
  97  * Number of buffers we will use.
  98  * 2 is usually enough for good buffering pipeline
  99  */
 100 #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
 101
 102 #endif /* CONFIG_USB_GADGET_DEBUG_FILES */
 103
 104 FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 105
 106 static int msg_do_config(struct usb_configuration *c)
 107 {
 108         int ret;
 109
 110         if (gadget_is_otg(c->cdev->gadget)) {
 111                 c->descriptors = otg_desc;
 112                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 113         }
 114
 115         f_msg = usb_get_function(fi_msg);
 116         if (IS_ERR(f_msg))
 117                 return PTR_ERR(f_msg);
 118
 119         ret = usb_add_function(c, f_msg);
 120         if (ret)
 121                 goto put_func;
 122
 123         return 0;
 124
 125 put_func:
 126         usb_put_function(f_msg);
 127         return ret;
 128 }
 129
 130 static struct usb_configuration msg_config_driver = {
 131         .label                  = "Linux File-Backed Storage",
 132         .bConfigurationValue    = 1,
 133         .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
 134 };
 135
 136
 137 /****************************** Gadget Bind ******************************/
 138
 139 static int msg_bind(struct usb_composite_dev *cdev)
 140 {
 141         struct fsg_opts *opts;
 142         struct fsg_config config;
 143         int status;
 144
 145         fi_msg = usb_get_function_instance("mass_storage");
 146         if (IS_ERR(fi_msg))
 147                 return PTR_ERR(fi_msg);
 148
 149         fsg_config_from_params(&config, &mod_data, fsg_num_buffers);
 150         opts = fsg_opts_from_func_inst(fi_msg);
 151
 152         opts->no_configfs = true;
 153         status = fsg_common_set_num_buffers(opts->common, fsg_num_buffers);
 154         if (status)
 155                 goto fail;
 156
 157         status = fsg_common_set_cdev(opts->common, cdev, config.can_stall);
 158         if (status)
 159                 goto fail_set_cdev;
 160
 161         fsg_common_set_sysfs(opts->common, true);
 162         status = fsg_common_create_luns(opts->common, &config);
 163         if (status)
 164                 goto fail_set_cdev;
 165
 166         fsg_common_set_inquiry_string(opts->common, config.vendor_name,
 167                                       config.product_name);
 168
 169         status = usb_string_ids_tab(cdev, strings_dev);
 170         if (status < 0)
 171                 goto fail_string_ids;
 172         msg_device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 173
 174         if (gadget_is_otg(cdev->gadget) && !otg_desc[0]) {
 175                 struct usb_descriptor_header *usb_desc;
 176
 177                 usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
 178                 if (!usb_desc)
 179                         goto fail_string_ids;
 180                 usb_otg_descriptor_init(cdev->gadget, usb_desc);
 181                 otg_desc[0] = usb_desc;
 182                 otg_desc[1] = NULL;
 183         }
 184
 185         status = usb_add_config(cdev, &msg_config_driver, msg_do_config);
 186         if (status < 0)
 187                 goto fail_otg_desc;
 188
 189         usb_composite_overwrite_options(cdev, &coverwrite);
 190         dev_info(&cdev->gadget->dev,
 191                  DRIVER_DESC ", version: " DRIVER_VERSION "\n");
 192         return 0;
 193
 194 fail_otg_desc:
 195         kfree(otg_desc[0]);
 196         otg_desc[0] = NULL;
 197 fail_string_ids:
 198         fsg_common_remove_luns(opts->common);
 199 fail_set_cdev:
 200         fsg_common_free_buffers(opts->common);
 201 fail:
 202         usb_put_function_instance(fi_msg);
 203         return status;
 204 }
 205
 206 static int msg_unbind(struct usb_composite_dev *cdev)
 207 {
 208         if (!IS_ERR(f_msg))
 209                 usb_put_function(f_msg);
 210
 211         if (!IS_ERR(fi_msg))
 212                 usb_put_function_instance(fi_msg);
 213
 214         kfree(otg_desc[0]);
 215         otg_desc[0] = NULL;
 216
 217         return 0;
 218 }
 219
 220 /****************************** Some noise ******************************/
 221
 222 static struct usb_composite_driver msg_driver = {
 223         .name           = "g_mass_storage",
 224         .dev            = &msg_device_desc,
 225         .max_speed      = USB_SPEED_SUPER_PLUS,
 226         .needs_serial   = 1,
 227         .strings        = dev_strings,
 228         .bind           = msg_bind,
 229         .unbind         = msg_unbind,
 230 };
 231
 232 module_usb_composite_driver(msg_driver);
 233
 234 MODULE_DESCRIPTION(DRIVER_DESC);
 235 MODULE_AUTHOR("Michal Nazarewicz");
 236 MODULE_LICENSE("GPL");