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