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/device.h>
  16
  17 #include "u_serial.h"
  18 #include "gadget_chips.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 gser_descs {
  31         struct usb_endpoint_descriptor  *in;
  32         struct usb_endpoint_descriptor  *out;
  33 };
  34
  35 struct f_gser {
  36         struct gserial                  port;
  37         u8                              data_id;
  38         u8                              port_num;
  39
  40         struct gser_descs               fs;
  41         struct gser_descs               hs;
  42 };
  43
  44 static inline struct f_gser *func_to_gser(struct usb_function *f)
  45 {
  46         return container_of(f, struct f_gser, port.func);
  47 }
  48
  49 /*-------------------------------------------------------------------------*/
  50
  51 /* interface descriptor: */
  52
  53 static struct usb_interface_descriptor gser_interface_desc __initdata = {
  54         .bLength =              USB_DT_INTERFACE_SIZE,
  55         .bDescriptorType =      USB_DT_INTERFACE,
  56         /* .bInterfaceNumber = DYNAMIC */
  57         .bNumEndpoints =        2,
  58         .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
  59         .bInterfaceSubClass =   0,
  60         .bInterfaceProtocol =   0,
  61         /* .iInterface = DYNAMIC */
  62 };
  63
  64 /* full speed support: */
  65
  66 static struct usb_endpoint_descriptor gser_fs_in_desc __initdata = {
  67         .bLength =              USB_DT_ENDPOINT_SIZE,
  68         .bDescriptorType =      USB_DT_ENDPOINT,
  69         .bEndpointAddress =     USB_DIR_IN,
  70         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  71 };
  72
  73 static struct usb_endpoint_descriptor gser_fs_out_desc __initdata = {
  74         .bLength =              USB_DT_ENDPOINT_SIZE,
  75         .bDescriptorType =      USB_DT_ENDPOINT,
  76         .bEndpointAddress =     USB_DIR_OUT,
  77         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  78 };
  79
  80 static struct usb_descriptor_header *gser_fs_function[] __initdata = {
  81         (struct usb_descriptor_header *) &gser_interface_desc,
  82         (struct usb_descriptor_header *) &gser_fs_in_desc,
  83         (struct usb_descriptor_header *) &gser_fs_out_desc,
  84         NULL,
  85 };
  86
  87 /* high speed support: */
  88
  89 static struct usb_endpoint_descriptor gser_hs_in_desc __initdata = {
  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_endpoint_descriptor gser_hs_out_desc __initdata = {
  97         .bLength =              USB_DT_ENDPOINT_SIZE,
  98         .bDescriptorType =      USB_DT_ENDPOINT,
  99         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 100         .wMaxPacketSize =       cpu_to_le16(512),
 101 };
 102
 103 static struct usb_descriptor_header *gser_hs_function[] __initdata = {
 104         (struct usb_descriptor_header *) &gser_interface_desc,
 105         (struct usb_descriptor_header *) &gser_hs_in_desc,
 106         (struct usb_descriptor_header *) &gser_hs_out_desc,
 107         NULL,
 108 };
 109
 110 /* string descriptors: */
 111
 112 static struct usb_string gser_string_defs[] = {
 113         [0].s = "Generic Serial",
 114         {  } /* end of list */
 115 };
 116
 117 static struct usb_gadget_strings gser_string_table = {
 118         .language =             0x0409, /* en-us */
 119         .strings =              gser_string_defs,
 120 };
 121
 122 static struct usb_gadget_strings *gser_strings[] = {
 123         &gser_string_table,
 124         NULL,
 125 };
 126
 127 /*-------------------------------------------------------------------------*/
 128
 129 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 130 {
 131         struct f_gser           *gser = func_to_gser(f);
 132         struct usb_composite_dev *cdev = f->config->cdev;
 133
 134         /* we know alt == 0, so this is an activation or a reset */
 135
 136         if (gser->port.in->driver_data) {
 137                 DBG(cdev, "reset generic ttyGS%d\n", gser->port_num);
 138                 gserial_disconnect(&gser->port);
 139         } else {
 140                 DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
 141                 gser->port.in_desc = ep_choose(cdev->gadget,
 142                                 gser->hs.in, gser->fs.in);
 143                 gser->port.out_desc = ep_choose(cdev->gadget,
 144                                 gser->hs.out, gser->fs.out);
 145         }
 146         gserial_connect(&gser->port, gser->port_num);
 147         return 0;
 148 }
 149
 150 static void gser_disable(struct usb_function *f)
 151 {
 152         struct f_gser   *gser = func_to_gser(f);
 153         struct usb_composite_dev *cdev = f->config->cdev;
 154
 155         DBG(cdev, "generic ttyGS%d deactivated\n", gser->port_num);
 156         gserial_disconnect(&gser->port);
 157 }
 158
 159 /*-------------------------------------------------------------------------*/
 160
 161 /* serial function driver setup/binding */
 162
 163 static int __init
 164 gser_bind(struct usb_configuration *c, struct usb_function *f)
 165 {
 166         struct usb_composite_dev *cdev = c->cdev;
 167         struct f_gser           *gser = func_to_gser(f);
 168         int                     status;
 169         struct usb_ep           *ep;
 170
 171         /* allocate instance-specific interface IDs */
 172         status = usb_interface_id(c, f);
 173         if (status < 0)
 174                 goto fail;
 175         gser->data_id = status;
 176         gser_interface_desc.bInterfaceNumber = status;
 177
 178         status = -ENODEV;
 179
 180         /* allocate instance-specific endpoints */
 181         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 182         if (!ep)
 183                 goto fail;
 184         gser->port.in = ep;
 185         ep->driver_data = cdev; /* claim */
 186
 187         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 188         if (!ep)
 189                 goto fail;
 190         gser->port.out = ep;
 191         ep->driver_data = cdev; /* claim */
 192
 193         /* copy descriptors, and track endpoint copies */
 194         f->descriptors = usb_copy_descriptors(gser_fs_function);
 195
 196         gser->fs.in = usb_find_endpoint(gser_fs_function,
 197                         f->descriptors, &gser_fs_in_desc);
 198         gser->fs.out = usb_find_endpoint(gser_fs_function,
 199                         f->descriptors, &gser_fs_out_desc);
 200
 201
 202         /* support all relevant hardware speeds... we expect that when
 203          * hardware is dual speed, all bulk-capable endpoints work at
 204          * both speeds
 205          */
 206         if (gadget_is_dualspeed(c->cdev->gadget)) {
 207                 gser_hs_in_desc.bEndpointAddress =
 208                                 gser_fs_in_desc.bEndpointAddress;
 209                 gser_hs_out_desc.bEndpointAddress =
 210                                 gser_fs_out_desc.bEndpointAddress;
 211
 212                 /* copy descriptors, and track endpoint copies */
 213                 f->hs_descriptors = usb_copy_descriptors(gser_hs_function);
 214
 215                 gser->hs.in = usb_find_endpoint(gser_hs_function,
 216                                 f->hs_descriptors, &gser_hs_in_desc);
 217                 gser->hs.out = usb_find_endpoint(gser_hs_function,
 218                                 f->hs_descriptors, &gser_hs_out_desc);
 219         }
 220
 221         DBG(cdev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
 222                         gser->port_num,
 223                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 224                         gser->port.in->name, gser->port.out->name);
 225         return 0;
 226
 227 fail:
 228         /* we might as well release our claims on endpoints */
 229         if (gser->port.out)
 230                 gser->port.out->driver_data = NULL;
 231         if (gser->port.in)
 232                 gser->port.in->driver_data = NULL;
 233
 234         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 235
 236         return status;
 237 }
 238
 239 static void
 240 gser_unbind(struct usb_configuration *c, struct usb_function *f)
 241 {
 242         if (gadget_is_dualspeed(c->cdev->gadget))
 243                 usb_free_descriptors(f->hs_descriptors);
 244         usb_free_descriptors(f->descriptors);
 245         kfree(func_to_gser(f));
 246 }
 247
 248 /**
 249  * gser_bind_config - add a generic serial function to a configuration
 250  * @c: the configuration to support the serial instance
 251  * @port_num: /dev/ttyGS* port this interface will use
 252  * Context: single threaded during gadget setup
 253  *
 254  * Returns zero on success, else negative errno.
 255  *
 256  * Caller must have called @gserial_setup() with enough ports to
 257  * handle all the ones it binds.  Caller is also responsible
 258  * for calling @gserial_cleanup() before module unload.
 259  */
 260 int __init gser_bind_config(struct usb_configuration *c, u8 port_num)
 261 {
 262         struct f_gser   *gser;
 263         int             status;
 264
 265         /* REVISIT might want instance-specific strings to help
 266          * distinguish instances ...
 267          */
 268
 269         /* maybe allocate device-global string ID */
 270         if (gser_string_defs[0].id == 0) {
 271                 status = usb_string_id(c->cdev);
 272                 if (status < 0)
 273                         return status;
 274                 gser_string_defs[0].id = status;
 275         }
 276
 277         /* allocate and initialize one new instance */
 278         gser = kzalloc(sizeof *gser, GFP_KERNEL);
 279         if (!gser)
 280                 return -ENOMEM;
 281
 282         gser->port_num = port_num;
 283
 284         gser->port.func.name = "gser";
 285         gser->port.func.strings = gser_strings;
 286         gser->port.func.bind = gser_bind;
 287         gser->port.func.unbind = gser_unbind;
 288         gser->port.func.set_alt = gser_set_alt;
 289         gser->port.func.disable = gser_disable;
 290
 291         status = usb_add_function(c, &gser->port.func);
 292         if (status)
 293                 kfree(gser);
 294         return status;
 295 }