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/kernel.h>
  14 #include <linux/device.h>
  15
  16 #include "u_serial.h"
  17 #include "gadget_chips.h"
  18
  19
  20 /*
  21  * This function packages a simple "generic serial" port with no real
  22  * control mechanisms, just raw data transfer over two bulk endpoints.
  23  *
  24  * Because it's not standardized, this isn't as interoperable as the
  25  * CDC ACM driver.  However, for many purposes it's just as functional
  26  * if you can arrange appropriate host side drivers.
  27  */
  28
  29 struct gser_descs {
  30         struct usb_endpoint_descriptor  *in;
  31         struct usb_endpoint_descriptor  *out;
  32 };
  33
  34 struct f_gser {
  35         struct gserial                  port;
  36         u8                              data_id;
  37         u8                              port_num;
  38
  39         struct gser_descs               fs;
  40         struct gser_descs               hs;
  41 };
  42
  43 static inline struct f_gser *func_to_gser(struct usb_function *f)
  44 {
  45         return container_of(f, struct f_gser, port.func);
  46 }
  47
  48 /*-------------------------------------------------------------------------*/
  49
  50 /* interface descriptor: */
  51
  52 static struct usb_interface_descriptor gser_interface_desc __initdata = {
  53         .bLength =              USB_DT_INTERFACE_SIZE,
  54         .bDescriptorType =      USB_DT_INTERFACE,
  55         /* .bInterfaceNumber = DYNAMIC */
  56         .bNumEndpoints =        2,
  57         .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
  58         .bInterfaceSubClass =   0,
  59         .bInterfaceProtocol =   0,
  60         /* .iInterface = DYNAMIC */
  61 };
  62
  63 /* full speed support: */
  64
  65 static struct usb_endpoint_descriptor gser_fs_in_desc __initdata = {
  66         .bLength =              USB_DT_ENDPOINT_SIZE,
  67         .bDescriptorType =      USB_DT_ENDPOINT,
  68         .bEndpointAddress =     USB_DIR_IN,
  69         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  70 };
  71
  72 static struct usb_endpoint_descriptor gser_fs_out_desc __initdata = {
  73         .bLength =              USB_DT_ENDPOINT_SIZE,
  74         .bDescriptorType =      USB_DT_ENDPOINT,
  75         .bEndpointAddress =     USB_DIR_OUT,
  76         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  77 };
  78
  79 static struct usb_descriptor_header *gser_fs_function[] __initdata = {
  80         (struct usb_descriptor_header *) &gser_interface_desc,
  81         (struct usb_descriptor_header *) &gser_fs_in_desc,
  82         (struct usb_descriptor_header *) &gser_fs_out_desc,
  83         NULL,
  84 };
  85
  86 /* high speed support: */
  87
  88 static struct usb_endpoint_descriptor gser_hs_in_desc __initdata = {
  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_endpoint_descriptor gser_hs_out_desc __initdata = {
  96         .bLength =              USB_DT_ENDPOINT_SIZE,
  97         .bDescriptorType =      USB_DT_ENDPOINT,
  98         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  99         .wMaxPacketSize =       cpu_to_le16(512),
 100 };
 101
 102 static struct usb_descriptor_header *gser_hs_function[] __initdata = {
 103         (struct usb_descriptor_header *) &gser_interface_desc,
 104         (struct usb_descriptor_header *) &gser_hs_in_desc,
 105         (struct usb_descriptor_header *) &gser_hs_out_desc,
 106         NULL,
 107 };
 108
 109 /* string descriptors: */
 110
 111 static struct usb_string gser_string_defs[] = {
 112         [0].s = "Generic Serial",
 113         {  } /* end of list */
 114 };
 115
 116 static struct usb_gadget_strings gser_string_table = {
 117         .language =             0x0409, /* en-us */
 118         .strings =              gser_string_defs,
 119 };
 120
 121 static struct usb_gadget_strings *gser_strings[] = {
 122         &gser_string_table,
 123         NULL,
 124 };
 125
 126 /*-------------------------------------------------------------------------*/
 127
 128 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 129 {
 130         struct f_gser           *gser = func_to_gser(f);
 131         struct usb_composite_dev *cdev = f->config->cdev;
 132
 133         /* we know alt == 0, so this is an activation or a reset */
 134
 135         if (gser->port.in->driver_data) {
 136                 DBG(cdev, "reset generic ttyGS%d\n", gser->port_num);
 137                 gserial_disconnect(&gser->port);
 138         } else {
 139                 DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
 140                 gser->port.in_desc = ep_choose(cdev->gadget,
 141                                 gser->hs.in, gser->fs.in);
 142                 gser->port.out_desc = ep_choose(cdev->gadget,
 143                                 gser->hs.out, gser->fs.out);
 144         }
 145         gserial_connect(&gser->port, gser->port_num);
 146         return 0;
 147 }
 148
 149 static void gser_disable(struct usb_function *f)
 150 {
 151         struct f_gser   *gser = func_to_gser(f);
 152         struct usb_composite_dev *cdev = f->config->cdev;
 153
 154         DBG(cdev, "generic ttyGS%d deactivated\n", gser->port_num);
 155         gserial_disconnect(&gser->port);
 156 }
 157
 158 /*-------------------------------------------------------------------------*/
 159
 160 /* serial function driver setup/binding */
 161
 162 static int __init
 163 gser_bind(struct usb_configuration *c, struct usb_function *f)
 164 {
 165         struct usb_composite_dev *cdev = c->cdev;
 166         struct f_gser           *gser = func_to_gser(f);
 167         int                     status;
 168         struct usb_ep           *ep;
 169
 170         /* allocate instance-specific interface IDs */
 171         status = usb_interface_id(c, f);
 172         if (status < 0)
 173                 goto fail;
 174         gser->data_id = status;
 175         gser_interface_desc.bInterfaceNumber = status;
 176
 177         status = -ENODEV;
 178
 179         /* allocate instance-specific endpoints */
 180         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 181         if (!ep)
 182                 goto fail;
 183         gser->port.in = ep;
 184         ep->driver_data = cdev; /* claim */
 185
 186         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 187         if (!ep)
 188                 goto fail;
 189         gser->port.out = ep;
 190         ep->driver_data = cdev; /* claim */
 191
 192         /* copy descriptors, and track endpoint copies */
 193         f->descriptors = usb_copy_descriptors(gser_fs_function);
 194
 195         gser->fs.in = usb_find_endpoint(gser_fs_function,
 196                         f->descriptors, &gser_fs_in_desc);
 197         gser->fs.out = usb_find_endpoint(gser_fs_function,
 198                         f->descriptors, &gser_fs_out_desc);
 199
 200
 201         /* support all relevant hardware speeds... we expect that when
 202          * hardware is dual speed, all bulk-capable endpoints work at
 203          * both speeds
 204          */
 205         if (gadget_is_dualspeed(c->cdev->gadget)) {
 206                 gser_hs_in_desc.bEndpointAddress =
 207                                 gser_fs_in_desc.bEndpointAddress;
 208                 gser_hs_out_desc.bEndpointAddress =
 209                                 gser_fs_out_desc.bEndpointAddress;
 210
 211                 /* copy descriptors, and track endpoint copies */
 212                 f->hs_descriptors = usb_copy_descriptors(gser_hs_function);
 213
 214                 gser->hs.in = usb_find_endpoint(gser_hs_function,
 215                                 f->hs_descriptors, &gser_hs_in_desc);
 216                 gser->hs.out = usb_find_endpoint(gser_hs_function,
 217                                 f->hs_descriptors, &gser_hs_out_desc);
 218         }
 219
 220         DBG(cdev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
 221                         gser->port_num,
 222                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 223                         gser->port.in->name, gser->port.out->name);
 224         return 0;
 225
 226 fail:
 227         /* we might as well release our claims on endpoints */
 228         if (gser->port.out)
 229                 gser->port.out->driver_data = NULL;
 230         if (gser->port.in)
 231                 gser->port.in->driver_data = NULL;
 232
 233         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 234
 235         return status;
 236 }
 237
 238 static void
 239 gser_unbind(struct usb_configuration *c, struct usb_function *f)
 240 {
 241         if (gadget_is_dualspeed(c->cdev->gadget))
 242                 usb_free_descriptors(f->hs_descriptors);
 243         usb_free_descriptors(f->descriptors);
 244         kfree(func_to_gser(f));
 245 }
 246
 247 /**
 248  * gser_bind_config - add a generic serial function to a configuration
 249  * @c: the configuration to support the serial instance
 250  * @port_num: /dev/ttyGS* port this interface will use
 251  * Context: single threaded during gadget setup
 252  *
 253  * Returns zero on success, else negative errno.
 254  *
 255  * Caller must have called @gserial_setup() with enough ports to
 256  * handle all the ones it binds.  Caller is also responsible
 257  * for calling @gserial_cleanup() before module unload.
 258  */
 259 int __init gser_bind_config(struct usb_configuration *c, u8 port_num)
 260 {
 261         struct f_gser   *gser;
 262         int             status;
 263
 264         /* REVISIT might want instance-specific strings to help
 265          * distinguish instances ...
 266          */
 267
 268         /* maybe allocate device-global string ID */
 269         if (gser_string_defs[0].id == 0) {
 270                 status = usb_string_id(c->cdev);
 271                 if (status < 0)
 272                         return status;
 273                 gser_string_defs[0].id = status;
 274         }
 275
 276         /* allocate and initialize one new instance */
 277         gser = kzalloc(sizeof *gser, GFP_KERNEL);
 278         if (!gser)
 279                 return -ENOMEM;
 280
 281         gser->port_num = port_num;
 282
 283         gser->port.func.name = "gser";
 284         gser->port.func.strings = gser_strings;
 285         gser->port.func.bind = gser_bind;
 286         gser->port.func.unbind = gser_unbind;
 287         gser->port.func.set_alt = gser_set_alt;
 288         gser->port.func.disable = gser_disable;
 289
 290         status = usb_add_function(c, &gser->port.func);
 291         if (status)
 292                 kfree(gser);
 293         return status;
 294 }