drivers/usb/gadget/zero.c

   1 /*
   2  * zero.c -- Gadget Zero, for USB development
   3  *
   4  * Copyright (C) 2003-2008 David Brownell
   5  * Copyright (C) 2008 by Nokia Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22
  23 /*
  24  * Gadget Zero only needs two bulk endpoints, and is an example of how you
  25  * can write a hardware-agnostic gadget driver running inside a USB device.
  26  * Some hardware details are visible, but don't affect most of the driver.
  27  *
  28  * Use it with the Linux host/master side "usbtest" driver to get a basic
  29  * functional test of your device-side usb stack, or with "usb-skeleton".
  30  *
  31  * It supports two similar configurations.  One sinks whatever the usb host
  32  * writes, and in return sources zeroes.  The other loops whatever the host
  33  * writes back, so the host can read it.
  34  *
  35  * Many drivers will only have one configuration, letting them be much
  36  * simpler if they also don't support high speed operation (like this
  37  * driver does).
  38  *
  39  * Why is *this* driver using two configurations, rather than setting up
  40  * two interfaces with different functions?  To help verify that multiple
  41  * configuration infrastucture is working correctly; also, so that it can
  42  * work with low capability USB controllers without four bulk endpoints.
  43  */
  44
  45 /*
  46  * driver assumes self-powered hardware, and
  47  * has no way for users to trigger remote wakeup.
  48  */
  49
  50 /* #define VERBOSE_DEBUG */
  51
  52 #include <linux/kernel.h>
  53 #include <linux/utsname.h>
  54 #include <linux/device.h>
  55
  56 #include "g_zero.h"
  57 #include "gadget_chips.h"
  58
  59
  60 /*-------------------------------------------------------------------------*/
  61
  62 #define DRIVER_VERSION          "Cinco de Mayo 2008"
  63
  64 static const char longname[] = "Gadget Zero";
  65
  66 unsigned buflen = 4096;
  67 module_param(buflen, uint, 0);
  68
  69 /*
  70  * Normally the "loopback" configuration is second (index 1) so
  71  * it's not the default.  Here's where to change that order, to
  72  * work better with hosts where config changes are problematic or
  73  * controllers (like original superh) that only support one config.
  74  */
  75 static int loopdefault = 0;
  76 module_param(loopdefault, bool, S_IRUGO|S_IWUSR);
  77
  78 /*-------------------------------------------------------------------------*/
  79
  80 /* Thanks to NetChip Technologies for donating this product ID.
  81  *
  82  * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
  83  * Instead:  allocate your own, using normal USB-IF procedures.
  84  */
  85 #ifndef CONFIG_USB_ZERO_HNPTEST
  86 #define DRIVER_VENDOR_NUM       0x0525          /* NetChip */
  87 #define DRIVER_PRODUCT_NUM      0xa4a0          /* Linux-USB "Gadget Zero" */
  88 #else
  89 #define DRIVER_VENDOR_NUM       0x1a0a          /* OTG test device IDs */
  90 #define DRIVER_PRODUCT_NUM      0xbadd
  91 #endif
  92
  93 /*-------------------------------------------------------------------------*/
  94
  95 static struct usb_device_descriptor device_desc = {
  96         .bLength =              sizeof device_desc,
  97         .bDescriptorType =      USB_DT_DEVICE,
  98
  99         .bcdUSB =               __constant_cpu_to_le16(0x0200),
 100         .bDeviceClass =         USB_CLASS_VENDOR_SPEC,
 101
 102         .idVendor =             __constant_cpu_to_le16(DRIVER_VENDOR_NUM),
 103         .idProduct =            __constant_cpu_to_le16(DRIVER_PRODUCT_NUM),
 104         .bNumConfigurations =   2,
 105 };
 106
 107 #ifdef CONFIG_USB_OTG
 108 static struct usb_otg_descriptor otg_descriptor = {
 109         .bLength =              sizeof otg_descriptor,
 110         .bDescriptorType =      USB_DT_OTG,
 111
 112         /* REVISIT SRP-only hardware is possible, although
 113          * it would not be called "OTG" ...
 114          */
 115         .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
 116 };
 117
 118 const struct usb_descriptor_header *otg_desc[] = {
 119         (struct usb_descriptor_header *) &otg_descriptor,
 120         NULL,
 121 };
 122 #endif
 123
 124 /* string IDs are assigned dynamically */
 125
 126 #define STRING_MANUFACTURER_IDX         0
 127 #define STRING_PRODUCT_IDX              1
 128 #define STRING_SERIAL_IDX               2
 129
 130 static char manufacturer[50];
 131
 132 /* default serial number takes at least two packets */
 133 static char serial[] = "0123456789.0123456789.0123456789";
 134
 135 static struct usb_string strings_dev[] = {
 136         [STRING_MANUFACTURER_IDX].s = manufacturer,
 137         [STRING_PRODUCT_IDX].s = longname,
 138         [STRING_SERIAL_IDX].s = serial,
 139         {  }                    /* end of list */
 140 };
 141
 142 static struct usb_gadget_strings stringtab_dev = {
 143         .language       = 0x0409,       /* en-us */
 144         .strings        = strings_dev,
 145 };
 146
 147 static struct usb_gadget_strings *dev_strings[] = {
 148         &stringtab_dev,
 149         NULL,
 150 };
 151
 152 /*-------------------------------------------------------------------------*/
 153
 154 struct usb_request *alloc_ep_req(struct usb_ep *ep)
 155 {
 156         struct usb_request      *req;
 157
 158         req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 159         if (req) {
 160                 req->length = buflen;
 161                 req->buf = kmalloc(buflen, GFP_ATOMIC);
 162                 if (!req->buf) {
 163                         usb_ep_free_request(ep, req);
 164                         req = NULL;
 165                 }
 166         }
 167         return req;
 168 }
 169
 170 void free_ep_req(struct usb_ep *ep, struct usb_request *req)
 171 {
 172         kfree(req->buf);
 173         usb_ep_free_request(ep, req);
 174 }
 175
 176 static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
 177 {
 178         int                     value;
 179
 180         if (ep->driver_data) {
 181                 value = usb_ep_disable(ep);
 182                 if (value < 0)
 183                         DBG(cdev, "disable %s --> %d\n",
 184                                         ep->name, value);
 185                 ep->driver_data = NULL;
 186         }
 187 }
 188
 189 void disable_endpoints(struct usb_composite_dev *cdev,
 190                 struct usb_ep *in, struct usb_ep *out)
 191 {
 192         disable_ep(cdev, in);
 193         disable_ep(cdev, out);
 194 }
 195
 196 /*-------------------------------------------------------------------------*/
 197
 198 static int __init zero_bind(struct usb_composite_dev *cdev)
 199 {
 200         int                     gcnum;
 201         struct usb_gadget       *gadget = cdev->gadget;
 202         int                     id;
 203
 204         /* Allocate string descriptor numbers ... note that string
 205          * contents can be overridden by the composite_dev glue.
 206          */
 207         id = usb_string_id(cdev);
 208         if (id < 0)
 209                 return id;
 210         strings_dev[STRING_MANUFACTURER_IDX].id = id;
 211         device_desc.iManufacturer = id;
 212
 213         id = usb_string_id(cdev);
 214         if (id < 0)
 215                 return id;
 216         strings_dev[STRING_PRODUCT_IDX].id = id;
 217         device_desc.iProduct = id;
 218
 219         id = usb_string_id(cdev);
 220         if (id < 0)
 221                 return id;
 222         strings_dev[STRING_SERIAL_IDX].id = id;
 223         device_desc.iSerialNumber = id;
 224
 225         /* Register primary, then secondary configuration.  Note that
 226          * SH3 only allows one config...
 227          */
 228         if (loopdefault) {
 229                 loopback_add(cdev);
 230                 if (!gadget_is_sh(gadget))
 231                         sourcesink_add(cdev);
 232         } else {
 233                 sourcesink_add(cdev);
 234                 if (!gadget_is_sh(gadget))
 235                         loopback_add(cdev);
 236         }
 237
 238         gcnum = usb_gadget_controller_number(gadget);
 239         if (gcnum >= 0)
 240                 device_desc.bcdDevice = cpu_to_le16(0x0200 + gcnum);
 241         else {
 242                 /* gadget zero is so simple (for now, no altsettings) that
 243                  * it SHOULD NOT have problems with bulk-capable hardware.
 244                  * so just warn about unrcognized controllers -- don't panic.
 245                  *
 246                  * things like configuration and altsetting numbering
 247                  * can need hardware-specific attention though.
 248                  */
 249                 pr_warning("%s: controller '%s' not recognized\n",
 250                         longname, gadget->name);
 251                 device_desc.bcdDevice = __constant_cpu_to_le16(0x9999);
 252         }
 253
 254
 255         INFO(cdev, "%s, version: " DRIVER_VERSION "\n", longname);
 256
 257         snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
 258                 init_utsname()->sysname, init_utsname()->release,
 259                 gadget->name);
 260
 261         return 0;
 262 }
 263
 264 static struct usb_composite_driver zero_driver = {
 265         .name           = "zero",
 266         .dev            = &device_desc,
 267         .strings        = dev_strings,
 268         .bind           = zero_bind,
 269 };
 270
 271 MODULE_AUTHOR("David Brownell");
 272 MODULE_LICENSE("GPL");
 273
 274 static int __init init(void)
 275 {
 276         return usb_composite_register(&zero_driver);
 277 }
 278 module_init(init);
 279
 280 static void __exit cleanup(void)
 281 {
 282         usb_composite_unregister(&zero_driver);
 283 }
 284 module_exit(cleanup);