drivers/usb/gadget/function/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                 dev_dbg(&cdev->gadget->dev,
 159                         "reset generic ttyGS%d\n", gser->port_num);
 160                 gserial_disconnect(&gser->port);
 161         }
 162         if (!gser->port.in->desc || !gser->port.out->desc) {
 163                 dev_dbg(&cdev->gadget->dev,
 164                         "activate generic ttyGS%d\n", gser->port_num);
 165                 if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
 166                     config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
 167                         gser->port.in->desc = NULL;
 168                         gser->port.out->desc = NULL;
 169                         return -EINVAL;
 170                 }
 171         }
 172         gserial_connect(&gser->port, gser->port_num);
 173         return 0;
 174 }
 175
 176 static void gser_disable(struct usb_function *f)
 177 {
 178         struct f_gser   *gser = func_to_gser(f);
 179         struct usb_composite_dev *cdev = f->config->cdev;
 180
 181         dev_dbg(&cdev->gadget->dev,
 182                 "generic ttyGS%d deactivated\n", gser->port_num);
 183         gserial_disconnect(&gser->port);
 184 }
 185
 186 /*-------------------------------------------------------------------------*/
 187
 188 /* serial function driver setup/binding */
 189
 190 static int gser_bind(struct usb_configuration *c, struct usb_function *f)
 191 {
 192         struct usb_composite_dev *cdev = c->cdev;
 193         struct f_gser           *gser = func_to_gser(f);
 194         int                     status;
 195         struct usb_ep           *ep;
 196
 197         /* REVISIT might want instance-specific strings to help
 198          * distinguish instances ...
 199          */
 200
 201         /* maybe allocate device-global string ID */
 202         if (gser_string_defs[0].id == 0) {
 203                 status = usb_string_id(c->cdev);
 204                 if (status < 0)
 205                         return status;
 206                 gser_string_defs[0].id = status;
 207         }
 208
 209         /* allocate instance-specific interface IDs */
 210         status = usb_interface_id(c, f);
 211         if (status < 0)
 212                 goto fail;
 213         gser->data_id = status;
 214         gser_interface_desc.bInterfaceNumber = status;
 215
 216         status = -ENODEV;
 217
 218         /* allocate instance-specific endpoints */
 219         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 220         if (!ep)
 221                 goto fail;
 222         gser->port.in = ep;
 223         ep->driver_data = cdev; /* claim */
 224
 225         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 226         if (!ep)
 227                 goto fail;
 228         gser->port.out = ep;
 229         ep->driver_data = cdev; /* claim */
 230
 231         /* support all relevant hardware speeds... we expect that when
 232          * hardware is dual speed, all bulk-capable endpoints work at
 233          * both speeds
 234          */
 235         gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 236         gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
 237
 238         gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 239         gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
 240
 241         status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
 242                         gser_ss_function);
 243         if (status)
 244                 goto fail;
 245         dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
 246                 gser->port_num,
 247                 gadget_is_superspeed(c->cdev->gadget) ? "super" :
 248                 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 249                 gser->port.in->name, gser->port.out->name);
 250         return 0;
 251
 252 fail:
 253         /* we might as well release our claims on endpoints */
 254         if (gser->port.out)
 255                 gser->port.out->driver_data = NULL;
 256         if (gser->port.in)
 257                 gser->port.in->driver_data = NULL;
 258
 259         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 260
 261         return status;
 262 }
 263
 264 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
 265 {
 266         return container_of(to_config_group(item), struct f_serial_opts,
 267                             func_inst.group);
 268 }
 269
 270 CONFIGFS_ATTR_STRUCT(f_serial_opts);
 271 static ssize_t f_serial_attr_show(struct config_item *item,
 272                                   struct configfs_attribute *attr,
 273                                   char *page)
 274 {
 275         struct f_serial_opts *opts = to_f_serial_opts(item);
 276         struct f_serial_opts_attribute *f_serial_opts_attr =
 277                 container_of(attr, struct f_serial_opts_attribute, attr);
 278         ssize_t ret = 0;
 279
 280         if (f_serial_opts_attr->show)
 281                 ret = f_serial_opts_attr->show(opts, page);
 282
 283         return ret;
 284 }
 285
 286 static void serial_attr_release(struct config_item *item)
 287 {
 288         struct f_serial_opts *opts = to_f_serial_opts(item);
 289
 290         usb_put_function_instance(&opts->func_inst);
 291 }
 292
 293 static struct configfs_item_operations serial_item_ops = {
 294         .release        = serial_attr_release,
 295         .show_attribute = f_serial_attr_show,
 296 };
 297
 298 static ssize_t f_serial_port_num_show(struct f_serial_opts *opts, char *page)
 299 {
 300         return sprintf(page, "%u\n", opts->port_num);
 301 }
 302
 303 static struct f_serial_opts_attribute f_serial_port_num =
 304         __CONFIGFS_ATTR_RO(port_num, f_serial_port_num_show);
 305
 306 static struct configfs_attribute *acm_attrs[] = {
 307         &f_serial_port_num.attr,
 308         NULL,
 309 };
 310
 311 static struct config_item_type serial_func_type = {
 312         .ct_item_ops    = &serial_item_ops,
 313         .ct_attrs       = acm_attrs,
 314         .ct_owner       = THIS_MODULE,
 315 };
 316
 317 static void gser_free_inst(struct usb_function_instance *f)
 318 {
 319         struct f_serial_opts *opts;
 320
 321         opts = container_of(f, struct f_serial_opts, func_inst);
 322         gserial_free_line(opts->port_num);
 323         kfree(opts);
 324 }
 325
 326 static struct usb_function_instance *gser_alloc_inst(void)
 327 {
 328         struct f_serial_opts *opts;
 329         int ret;
 330
 331         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 332         if (!opts)
 333                 return ERR_PTR(-ENOMEM);
 334
 335         opts->func_inst.free_func_inst = gser_free_inst;
 336         ret = gserial_alloc_line(&opts->port_num);
 337         if (ret) {
 338                 kfree(opts);
 339                 return ERR_PTR(ret);
 340         }
 341         config_group_init_type_name(&opts->func_inst.group, "",
 342                                     &serial_func_type);
 343
 344         return &opts->func_inst;
 345 }
 346
 347 static void gser_free(struct usb_function *f)
 348 {
 349         struct f_gser *serial;
 350
 351         serial = func_to_gser(f);
 352         kfree(serial);
 353 }
 354
 355 static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
 356 {
 357         usb_free_all_descriptors(f);
 358 }
 359
 360 static struct usb_function *gser_alloc(struct usb_function_instance *fi)
 361 {
 362         struct f_gser   *gser;
 363         struct f_serial_opts *opts;
 364
 365         /* allocate and initialize one new instance */
 366         gser = kzalloc(sizeof(*gser), GFP_KERNEL);
 367         if (!gser)
 368                 return ERR_PTR(-ENOMEM);
 369
 370         opts = container_of(fi, struct f_serial_opts, func_inst);
 371
 372         gser->port_num = opts->port_num;
 373
 374         gser->port.func.name = "gser";
 375         gser->port.func.strings = gser_strings;
 376         gser->port.func.bind = gser_bind;
 377         gser->port.func.unbind = gser_unbind;
 378         gser->port.func.set_alt = gser_set_alt;
 379         gser->port.func.disable = gser_disable;
 380         gser->port.func.free_func = gser_free;
 381
 382         return &gser->port.func;
 383 }
 384
 385 DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
 386 MODULE_LICENSE("GPL");
 387 MODULE_AUTHOR("Al Borchers");
 388 MODULE_AUTHOR("David Brownell");