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