drivers/usb/gadget/legacy/serial.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * serial.c -- USB gadget serial driver
   4  *
   5  * Copyright (C) 2003 Al Borchers ([email protected])
   6  * Copyright (C) 2008 by David Brownell
   7  * Copyright (C) 2008 by Nokia Corporation
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/device.h>
  12 #include <linux/kstrtox.h>
  13 #include <linux/module.h>
  14 #include <linux/tty.h>
  15 #include <linux/tty_flip.h>
  16
  17 #include "u_serial.h"
  18
  19
  20 /* Defines */
  21
  22 #define GS_VERSION_STR                  "v2.4"
  23 #define GS_VERSION_NUM                  0x2400
  24
  25 #define GS_LONG_NAME                    "Gadget Serial"
  26 #define GS_VERSION_NAME                 GS_LONG_NAME " " GS_VERSION_STR
  27
  28 /*-------------------------------------------------------------------------*/
  29 USB_GADGET_COMPOSITE_OPTIONS();
  30
  31 /* Thanks to NetChip Technologies for donating this product ID.
  32 *
  33 * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
  34 * Instead:  allocate your own, using normal USB-IF procedures.
  35 */
  36 #define GS_VENDOR_ID                    0x0525  /* NetChip */
  37 #define GS_PRODUCT_ID                   0xa4a6  /* Linux-USB Serial Gadget */
  38 #define GS_CDC_PRODUCT_ID               0xa4a7  /* ... as CDC-ACM */
  39 #define GS_CDC_OBEX_PRODUCT_ID          0xa4a9  /* ... as CDC-OBEX */
  40
  41 /* string IDs are assigned dynamically */
  42
  43 #define STRING_DESCRIPTION_IDX          USB_GADGET_FIRST_AVAIL_IDX
  44
  45 static struct usb_string strings_dev[] = {
  46         [USB_GADGET_MANUFACTURER_IDX].s = "",
  47         [USB_GADGET_PRODUCT_IDX].s = GS_VERSION_NAME,
  48         [USB_GADGET_SERIAL_IDX].s = "",
  49         [STRING_DESCRIPTION_IDX].s = NULL /* updated; f(use_acm) */,
  50         {  } /* end of list */
  51 };
  52
  53 static struct usb_gadget_strings stringtab_dev = {
  54         .language       = 0x0409,       /* en-us */
  55         .strings        = strings_dev,
  56 };
  57
  58 static struct usb_gadget_strings *dev_strings[] = {
  59         &stringtab_dev,
  60         NULL,
  61 };
  62
  63 static struct usb_device_descriptor device_desc = {
  64         .bLength =              USB_DT_DEVICE_SIZE,
  65         .bDescriptorType =      USB_DT_DEVICE,
  66         /* .bcdUSB = DYNAMIC */
  67         /* .bDeviceClass = f(use_acm) */
  68         .bDeviceSubClass =      0,
  69         .bDeviceProtocol =      0,
  70         /* .bMaxPacketSize0 = f(hardware) */
  71         .idVendor =             cpu_to_le16(GS_VENDOR_ID),
  72         /* .idProduct = f(use_acm) */
  73         .bcdDevice = cpu_to_le16(GS_VERSION_NUM),
  74         /* .iManufacturer = DYNAMIC */
  75         /* .iProduct = DYNAMIC */
  76         .bNumConfigurations =   1,
  77 };
  78
  79 static const struct usb_descriptor_header *otg_desc[2];
  80
  81 /*-------------------------------------------------------------------------*/
  82
  83 /* Module */
  84 MODULE_DESCRIPTION(GS_VERSION_NAME);
  85 MODULE_AUTHOR("Al Borchers");
  86 MODULE_AUTHOR("David Brownell");
  87 MODULE_LICENSE("GPL");
  88
  89 static bool use_acm = true;
  90 module_param(use_acm, bool, 0);
  91 MODULE_PARM_DESC(use_acm, "Use CDC ACM, default=yes");
  92
  93 static bool use_obex = false;
  94 module_param(use_obex, bool, 0);
  95 MODULE_PARM_DESC(use_obex, "Use CDC OBEX, default=no");
  96
  97 static unsigned n_ports = 1;
  98 module_param(n_ports, uint, 0);
  99 MODULE_PARM_DESC(n_ports, "number of ports to create, default=1");
 100
 101 static bool enable = true;
 102
 103 static int switch_gserial_enable(bool do_enable);
 104
 105 static int enable_set(const char *s, const struct kernel_param *kp)
 106 {
 107         bool do_enable;
 108         int ret;
 109
 110         if (!s) /* called for no-arg enable == default */
 111                 return 0;
 112
 113         ret = kstrtobool(s, &do_enable);
 114         if (ret || enable == do_enable)
 115                 return ret;
 116
 117         ret = switch_gserial_enable(do_enable);
 118         if (!ret)
 119                 enable = do_enable;
 120
 121         return ret;
 122 }
 123
 124 static const struct kernel_param_ops enable_ops = {
 125         .set = enable_set,
 126         .get = param_get_bool,
 127 };
 128
 129 module_param_cb(enable, &enable_ops, &enable, 0644);
 130
 131 /*-------------------------------------------------------------------------*/
 132
 133 static struct usb_configuration serial_config_driver = {
 134         /* .label = f(use_acm) */
 135         /* .bConfigurationValue = f(use_acm) */
 136         /* .iConfiguration = DYNAMIC */
 137         .bmAttributes   = USB_CONFIG_ATT_SELFPOWER,
 138 };
 139
 140 static struct usb_function_instance *fi_serial[MAX_U_SERIAL_PORTS];
 141 static struct usb_function *f_serial[MAX_U_SERIAL_PORTS];
 142
 143 static int serial_register_ports(struct usb_composite_dev *cdev,
 144                 struct usb_configuration *c, const char *f_name)
 145 {
 146         int i;
 147         int ret;
 148
 149         ret = usb_add_config_only(cdev, c);
 150         if (ret)
 151                 goto out;
 152
 153         for (i = 0; i < n_ports; i++) {
 154
 155                 fi_serial[i] = usb_get_function_instance(f_name);
 156                 if (IS_ERR(fi_serial[i])) {
 157                         ret = PTR_ERR(fi_serial[i]);
 158                         goto fail;
 159                 }
 160
 161                 f_serial[i] = usb_get_function(fi_serial[i]);
 162                 if (IS_ERR(f_serial[i])) {
 163                         ret = PTR_ERR(f_serial[i]);
 164                         goto err_get_func;
 165                 }
 166
 167                 ret = usb_add_function(c, f_serial[i]);
 168                 if (ret)
 169                         goto err_add_func;
 170         }
 171
 172         return 0;
 173
 174 err_add_func:
 175         usb_put_function(f_serial[i]);
 176 err_get_func:
 177         usb_put_function_instance(fi_serial[i]);
 178
 179 fail:
 180         i--;
 181         while (i >= 0) {
 182                 usb_remove_function(c, f_serial[i]);
 183                 usb_put_function(f_serial[i]);
 184                 usb_put_function_instance(fi_serial[i]);
 185                 i--;
 186         }
 187 out:
 188         return ret;
 189 }
 190
 191 static int gs_bind(struct usb_composite_dev *cdev)
 192 {
 193         int                     status;
 194
 195         /* Allocate string descriptor numbers ... note that string
 196          * contents can be overridden by the composite_dev glue.
 197          */
 198
 199         status = usb_string_ids_tab(cdev, strings_dev);
 200         if (status < 0)
 201                 goto fail;
 202         device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
 203         device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 204         status = strings_dev[STRING_DESCRIPTION_IDX].id;
 205         serial_config_driver.iConfiguration = status;
 206
 207         if (gadget_is_otg(cdev->gadget)) {
 208                 if (!otg_desc[0]) {
 209                         struct usb_descriptor_header *usb_desc;
 210
 211                         usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
 212                         if (!usb_desc) {
 213                                 status = -ENOMEM;
 214                                 goto fail;
 215                         }
 216                         usb_otg_descriptor_init(cdev->gadget, usb_desc);
 217                         otg_desc[0] = usb_desc;
 218                         otg_desc[1] = NULL;
 219                 }
 220                 serial_config_driver.descriptors = otg_desc;
 221                 serial_config_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 222         }
 223
 224         /* register our configuration */
 225         if (use_acm) {
 226                 status  = serial_register_ports(cdev, &serial_config_driver,
 227                                 "acm");
 228                 usb_ep_autoconfig_reset(cdev->gadget);
 229         } else if (use_obex)
 230                 status = serial_register_ports(cdev, &serial_config_driver,
 231                                 "obex");
 232         else {
 233                 status = serial_register_ports(cdev, &serial_config_driver,
 234                                 "gser");
 235         }
 236         if (status < 0)
 237                 goto fail1;
 238
 239         usb_composite_overwrite_options(cdev, &coverwrite);
 240         INFO(cdev, "%s\n", GS_VERSION_NAME);
 241
 242         return 0;
 243 fail1:
 244         kfree(otg_desc[0]);
 245         otg_desc[0] = NULL;
 246 fail:
 247         return status;
 248 }
 249
 250 static int gs_unbind(struct usb_composite_dev *cdev)
 251 {
 252         int i;
 253
 254         for (i = 0; i < n_ports; i++) {
 255                 usb_put_function(f_serial[i]);
 256                 usb_put_function_instance(fi_serial[i]);
 257         }
 258
 259         kfree(otg_desc[0]);
 260         otg_desc[0] = NULL;
 261
 262         return 0;
 263 }
 264
 265 static struct usb_composite_driver gserial_driver = {
 266         .name           = "g_serial",
 267         .dev            = &device_desc,
 268         .strings        = dev_strings,
 269         .max_speed      = USB_SPEED_SUPER,
 270         .bind           = gs_bind,
 271         .unbind         = gs_unbind,
 272 };
 273
 274 static int switch_gserial_enable(bool do_enable)
 275 {
 276         if (!serial_config_driver.label)
 277                 /* gserial_init() was not called, yet */
 278                 return 0;
 279
 280         if (do_enable)
 281                 return usb_composite_probe(&gserial_driver);
 282
 283         usb_composite_unregister(&gserial_driver);
 284         return 0;
 285 }
 286
 287 static int __init gserial_init(void)
 288 {
 289         /* We *could* export two configs; that'd be much cleaner...
 290          * but neither of these product IDs was defined that way.
 291          */
 292         if (use_acm) {
 293                 serial_config_driver.label = "CDC ACM config";
 294                 serial_config_driver.bConfigurationValue = 2;
 295                 device_desc.bDeviceClass = USB_CLASS_COMM;
 296                 device_desc.idProduct =
 297                                 cpu_to_le16(GS_CDC_PRODUCT_ID);
 298         } else if (use_obex) {
 299                 serial_config_driver.label = "CDC OBEX config";
 300                 serial_config_driver.bConfigurationValue = 3;
 301                 device_desc.bDeviceClass = USB_CLASS_COMM;
 302                 device_desc.idProduct =
 303                         cpu_to_le16(GS_CDC_OBEX_PRODUCT_ID);
 304         } else {
 305                 serial_config_driver.label = "Generic Serial config";
 306                 serial_config_driver.bConfigurationValue = 1;
 307                 device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
 308                 device_desc.idProduct =
 309                                 cpu_to_le16(GS_PRODUCT_ID);
 310         }
 311         strings_dev[STRING_DESCRIPTION_IDX].s = serial_config_driver.label;
 312
 313         if (!enable)
 314                 return 0;
 315
 316         return usb_composite_probe(&gserial_driver);
 317 }
 318 module_init(gserial_init);
 319
 320 static void __exit gserial_cleanup(void)
 321 {
 322         if (enable)
 323                 usb_composite_unregister(&gserial_driver);
 324 }
 325 module_exit(gserial_cleanup);