drivers/usb/gadget/f_serial.c

   1 /*
   2  * f_serial.c - generic USB serial function driver
   3  *
   4  * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
   5  * Copyright (C) 2008 by David Brownell
   6  * Copyright (C) 2008 by Nokia Corporation
   7  *
   8  * This software is distributed under the terms of the GNU General
   9  * Public License ("GPL") as published by the Free Software Foundation,
  10  * either version 2 of that License or (at your option) any later version.
  11  */
  12
  13 #include <linux/slab.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17
  18 #include "u_serial.h"
  19 #include "gadget_chips.h"
  20
  21
  22 /*
  23  * This function packages a simple "generic serial" port with no real
  24  * control mechanisms, just raw data transfer over two bulk endpoints.
  25  *
  26  * Because it's not standardized, this isn't as interoperable as the
  27  * CDC ACM driver.  However, for many purposes it's just as functional
  28  * if you can arrange appropriate host side drivers.
  29  */
  30
  31 struct f_gser {
  32         struct gserial                  port;
  33         u8                              data_id;
  34         u8                              port_num;
  35 };
  36
  37 static inline struct f_gser *func_to_gser(struct usb_function *f)
  38 {
  39         return container_of(f, struct f_gser, port.func);
  40 }
  41
  42 /*-------------------------------------------------------------------------*/
  43
  44 /* interface descriptor: */
  45
  46 static struct usb_interface_descriptor gser_interface_desc = {
  47         .bLength =              USB_DT_INTERFACE_SIZE,
  48         .bDescriptorType =      USB_DT_INTERFACE,
  49         /* .bInterfaceNumber = DYNAMIC */
  50         .bNumEndpoints =        2,
  51         .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
  52         .bInterfaceSubClass =   0,
  53         .bInterfaceProtocol =   0,
  54         /* .iInterface = DYNAMIC */
  55 };
  56
  57 /* full speed support: */
  58
  59 static struct usb_endpoint_descriptor gser_fs_in_desc = {
  60         .bLength =              USB_DT_ENDPOINT_SIZE,
  61         .bDescriptorType =      USB_DT_ENDPOINT,
  62         .bEndpointAddress =     USB_DIR_IN,
  63         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  64 };
  65
  66 static struct usb_endpoint_descriptor gser_fs_out_desc = {
  67         .bLength =              USB_DT_ENDPOINT_SIZE,
  68         .bDescriptorType =      USB_DT_ENDPOINT,
  69         .bEndpointAddress =     USB_DIR_OUT,
  70         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  71 };
  72
  73 static struct usb_descriptor_header *gser_fs_function[] = {
  74         (struct usb_descriptor_header *) &gser_interface_desc,
  75         (struct usb_descriptor_header *) &gser_fs_in_desc,
  76         (struct usb_descriptor_header *) &gser_fs_out_desc,
  77         NULL,
  78 };
  79
  80 /* high speed support: */
  81
  82 static struct usb_endpoint_descriptor gser_hs_in_desc = {
  83         .bLength =              USB_DT_ENDPOINT_SIZE,
  84         .bDescriptorType =      USB_DT_ENDPOINT,
  85         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  86         .wMaxPacketSize =       cpu_to_le16(512),
  87 };
  88
  89 static struct usb_endpoint_descriptor gser_hs_out_desc = {
  90         .bLength =              USB_DT_ENDPOINT_SIZE,
  91         .bDescriptorType =      USB_DT_ENDPOINT,
  92         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  93         .wMaxPacketSize =       cpu_to_le16(512),
  94 };
  95
  96 static struct usb_descriptor_header *gser_hs_function[] = {
  97         (struct usb_descriptor_header *) &gser_interface_desc,
  98         (struct usb_descriptor_header *) &gser_hs_in_desc,
  99         (struct usb_descriptor_header *) &gser_hs_out_desc,
 100         NULL,
 101 };
 102
 103 static struct usb_endpoint_descriptor gser_ss_in_desc = {
 104         .bLength =              USB_DT_ENDPOINT_SIZE,
 105         .bDescriptorType =      USB_DT_ENDPOINT,
 106         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 107         .wMaxPacketSize =       cpu_to_le16(1024),
 108 };
 109
 110 static struct usb_endpoint_descriptor gser_ss_out_desc = {
 111         .bLength =              USB_DT_ENDPOINT_SIZE,
 112         .bDescriptorType =      USB_DT_ENDPOINT,
 113         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 114         .wMaxPacketSize =       cpu_to_le16(1024),
 115 };
 116
 117 static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = {
 118         .bLength =              sizeof gser_ss_bulk_comp_desc,
 119         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 120 };
 121
 122 static struct usb_descriptor_header *gser_ss_function[] = {
 123         (struct usb_descriptor_header *) &gser_interface_desc,
 124         (struct usb_descriptor_header *) &gser_ss_in_desc,
 125         (struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
 126         (struct usb_descriptor_header *) &gser_ss_out_desc,
 127         (struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
 128         NULL,
 129 };
 130
 131 /* string descriptors: */
 132
 133 static struct usb_string gser_string_defs[] = {
 134         [0].s = "Generic Serial",
 135         {  } /* end of list */
 136 };
 137
 138 static struct usb_gadget_strings gser_string_table = {
 139         .language =             0x0409, /* en-us */
 140         .strings =              gser_string_defs,
 141 };
 142
 143 static struct usb_gadget_strings *gser_strings[] = {
 144         &gser_string_table,
 145         NULL,
 146 };
 147
 148 /*-------------------------------------------------------------------------*/
 149
 150 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 151 {
 152         struct f_gser           *gser = func_to_gser(f);
 153         struct usb_composite_dev *cdev = f->config->cdev;
 154
 155         /* we know alt == 0, so this is an activation or a reset */
 156
 157         if (gser->port.in->driver_data) {
 158                 DBG(cdev, "reset generic ttyGS%d\n", gser->port_num);
 159                 gserial_disconnect(&gser->port);
 160         }
 161         if (!gser->port.in->desc || !gser->port.out->desc) {
 162                 DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
 163                 if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
 164                     config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
 165                         gser->port.in->desc = NULL;
 166                         gser->port.out->desc = NULL;
 167                         return -EINVAL;
 168                 }
 169         }
 170         gserial_connect(&gser->port, gser->port_num);
 171         return 0;
 172 }
 173
 174 static void gser_disable(struct usb_function *f)
 175 {
 176         struct f_gser   *gser = func_to_gser(f);
 177         struct usb_composite_dev *cdev = f->config->cdev;
 178
 179         DBG(cdev, "generic ttyGS%d deactivated\n", gser->port_num);
 180         gserial_disconnect(&gser->port);
 181 }
 182
 183 /*-------------------------------------------------------------------------*/
 184
 185 /* serial function driver setup/binding */
 186
 187 static int gser_bind(struct usb_configuration *c, struct usb_function *f)
 188 {
 189         struct usb_composite_dev *cdev = c->cdev;
 190         struct f_gser           *gser = func_to_gser(f);
 191         int                     status;
 192         struct usb_ep           *ep;
 193
 194         /* REVISIT might want instance-specific strings to help
 195          * distinguish instances ...
 196          */
 197
 198         /* maybe allocate device-global string ID */
 199         if (gser_string_defs[0].id == 0) {
 200                 status = usb_string_id(c->cdev);
 201                 if (status < 0)
 202                         return status;
 203                 gser_string_defs[0].id = status;
 204         }
 205
 206         /* allocate instance-specific interface IDs */
 207         status = usb_interface_id(c, f);
 208         if (status < 0)
 209                 goto fail;
 210         gser->data_id = status;
 211         gser_interface_desc.bInterfaceNumber = status;
 212
 213         status = -ENODEV;
 214
 215         /* allocate instance-specific endpoints */
 216         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 217         if (!ep)
 218                 goto fail;
 219         gser->port.in = ep;
 220         ep->driver_data = cdev; /* claim */
 221
 222         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 223         if (!ep)
 224                 goto fail;
 225         gser->port.out = ep;
 226         ep->driver_data = cdev; /* claim */
 227
 228         /* support all relevant hardware speeds... we expect that when
 229          * hardware is dual speed, all bulk-capable endpoints work at
 230          * both speeds
 231          */
 232         gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 233         gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
 234
 235         gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 236         gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
 237
 238         status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
 239                         gser_ss_function);
 240         if (status)
 241                 goto fail;
 242         DBG(cdev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
 243                         gser->port_num,
 244                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 245                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 246                         gser->port.in->name, gser->port.out->name);
 247         return 0;
 248
 249 fail:
 250         /* we might as well release our claims on endpoints */
 251         if (gser->port.out)
 252                 gser->port.out->driver_data = NULL;
 253         if (gser->port.in)
 254                 gser->port.in->driver_data = NULL;
 255
 256         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 257
 258         return status;
 259 }
 260
 261 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
 262 {
 263         return container_of(to_config_group(item), struct f_serial_opts,
 264                             func_inst.group);
 265 }
 266
 267 CONFIGFS_ATTR_STRUCT(f_serial_opts);
 268 static ssize_t f_serial_attr_show(struct config_item *item,
 269                                   struct configfs_attribute *attr,
 270                                   char *page)
 271 {
 272         struct f_serial_opts *opts = to_f_serial_opts(item);
 273         struct f_serial_opts_attribute *f_serial_opts_attr =
 274                 container_of(attr, struct f_serial_opts_attribute, attr);
 275         ssize_t ret = 0;
 276
 277         if (f_serial_opts_attr->show)
 278                 ret = f_serial_opts_attr->show(opts, page);
 279
 280         return ret;
 281 }
 282
 283 static void serial_attr_release(struct config_item *item)
 284 {
 285         struct f_serial_opts *opts = to_f_serial_opts(item);
 286
 287         usb_put_function_instance(&opts->func_inst);
 288 }
 289
 290 static struct configfs_item_operations serial_item_ops = {
 291         .release        = serial_attr_release,
 292         .show_attribute = f_serial_attr_show,
 293 };
 294
 295 static ssize_t f_serial_port_num_show(struct f_serial_opts *opts, char *page)
 296 {
 297         return sprintf(page, "%u\n", opts->port_num);
 298 }
 299
 300 static struct f_serial_opts_attribute f_serial_port_num =
 301         __CONFIGFS_ATTR_RO(port_num, f_serial_port_num_show);
 302
 303 static struct configfs_attribute *acm_attrs[] = {
 304         &f_serial_port_num.attr,
 305         NULL,
 306 };
 307
 308 static struct config_item_type serial_func_type = {
 309         .ct_item_ops    = &serial_item_ops,
 310         .ct_attrs       = acm_attrs,
 311         .ct_owner       = THIS_MODULE,
 312 };
 313
 314 static void gser_free_inst(struct usb_function_instance *f)
 315 {
 316         struct f_serial_opts *opts;
 317
 318         opts = container_of(f, struct f_serial_opts, func_inst);
 319         gserial_free_line(opts->port_num);
 320         kfree(opts);
 321 }
 322
 323 static struct usb_function_instance *gser_alloc_inst(void)
 324 {
 325         struct f_serial_opts *opts;
 326         int ret;
 327
 328         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 329         if (!opts)
 330                 return ERR_PTR(-ENOMEM);
 331
 332         opts->func_inst.free_func_inst = gser_free_inst;
 333         ret = gserial_alloc_line(&opts->port_num);
 334         if (ret) {
 335                 kfree(opts);
 336                 return ERR_PTR(ret);
 337         }
 338         config_group_init_type_name(&opts->func_inst.group, "",
 339                                     &serial_func_type);
 340
 341         return &opts->func_inst;
 342 }
 343
 344 static void gser_free(struct usb_function *f)
 345 {
 346         struct f_gser *serial;
 347
 348         serial = func_to_gser(f);
 349         kfree(serial);
 350 }
 351
 352 static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
 353 {
 354         usb_free_all_descriptors(f);
 355 }
 356
 357 struct usb_function *gser_alloc(struct usb_function_instance *fi)
 358 {
 359         struct f_gser   *gser;
 360         struct f_serial_opts *opts;
 361
 362         /* allocate and initialize one new instance */
 363         gser = kzalloc(sizeof(*gser), GFP_KERNEL);
 364         if (!gser)
 365                 return ERR_PTR(-ENOMEM);
 366
 367         opts = container_of(fi, struct f_serial_opts, func_inst);
 368
 369         gser->port_num = opts->port_num;
 370
 371         gser->port.func.name = "gser";
 372         gser->port.func.strings = gser_strings;
 373         gser->port.func.bind = gser_bind;
 374         gser->port.func.unbind = gser_unbind;
 375         gser->port.func.set_alt = gser_set_alt;
 376         gser->port.func.disable = gser_disable;
 377         gser->port.func.free_func = gser_free;
 378
 379         return &gser->port.func;
 380 }
 381
 382 DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
 383 MODULE_LICENSE("GPL");
 384 MODULE_AUTHOR("Al Borchers");
 385 MODULE_AUTHOR("David Brownell");