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 usb_descriptor_header    **fs_function;
  40         struct gser_descs               fs;
  41         struct usb_descriptor_header    **hs_function;
  42         struct gser_descs               hs;
  43 };
  44
  45 static inline struct f_gser *func_to_gser(struct usb_function *f)
  46 {
  47         return container_of(f, struct f_gser, port.func);
  48 }
  49
  50 /*-------------------------------------------------------------------------*/
  51
  52 /* interface descriptor: */
  53
  54 static struct usb_interface_descriptor gser_interface_desc __initdata = {
  55         .bLength =              USB_DT_INTERFACE_SIZE,
  56         .bDescriptorType =      USB_DT_INTERFACE,
  57         /* .bInterfaceNumber = DYNAMIC */
  58         .bNumEndpoints =        2,
  59         .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
  60         .bInterfaceSubClass =   0,
  61         .bInterfaceProtocol =   0,
  62         /* .iInterface = DYNAMIC */
  63 };
  64
  65 /* full speed support: */
  66
  67 static struct usb_endpoint_descriptor gser_fs_in_desc __initdata = {
  68         .bLength =              USB_DT_ENDPOINT_SIZE,
  69         .bDescriptorType =      USB_DT_ENDPOINT,
  70         .bEndpointAddress =     USB_DIR_IN,
  71         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  72 };
  73
  74 static struct usb_endpoint_descriptor gser_fs_out_desc __initdata = {
  75         .bLength =              USB_DT_ENDPOINT_SIZE,
  76         .bDescriptorType =      USB_DT_ENDPOINT,
  77         .bEndpointAddress =     USB_DIR_OUT,
  78         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  79 };
  80
  81 static struct usb_descriptor_header *gser_fs_function[] __initdata = {
  82         (struct usb_descriptor_header *) &gser_interface_desc,
  83         (struct usb_descriptor_header *) &gser_fs_in_desc,
  84         (struct usb_descriptor_header *) &gser_fs_out_desc,
  85         NULL,
  86 };
  87
  88 /* high speed support: */
  89
  90 static struct usb_endpoint_descriptor gser_hs_in_desc __initdata = {
  91         .bLength =              USB_DT_ENDPOINT_SIZE,
  92         .bDescriptorType =      USB_DT_ENDPOINT,
  93         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  94         .wMaxPacketSize =       __constant_cpu_to_le16(512),
  95 };
  96
  97 static struct usb_endpoint_descriptor gser_hs_out_desc __initdata = {
  98         .bLength =              USB_DT_ENDPOINT_SIZE,
  99         .bDescriptorType =      USB_DT_ENDPOINT,
 100         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 101         .wMaxPacketSize =       __constant_cpu_to_le16(512),
 102 };
 103
 104 static struct usb_descriptor_header *gser_hs_function[] __initdata = {
 105         (struct usb_descriptor_header *) &gser_interface_desc,
 106         (struct usb_descriptor_header *) &gser_hs_in_desc,
 107         (struct usb_descriptor_header *) &gser_hs_out_desc,
 108         NULL,
 109 };
 110
 111 /* string descriptors: */
 112
 113 static struct usb_string gser_string_defs[] = {
 114         [0].s = "Generic Serial",
 115         {  } /* end of list */
 116 };
 117
 118 static struct usb_gadget_strings gser_string_table = {
 119         .language =             0x0409, /* en-us */
 120         .strings =              gser_string_defs,
 121 };
 122
 123 static struct usb_gadget_strings *gser_strings[] = {
 124         &gser_string_table,
 125         NULL,
 126 };
 127
 128 /*-------------------------------------------------------------------------*/
 129
 130 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 131 {
 132         struct f_gser           *gser = func_to_gser(f);
 133         struct usb_composite_dev *cdev = f->config->cdev;
 134
 135         /* we know alt == 0, so this is an activation or a reset */
 136
 137         if (gser->port.in->driver_data) {
 138                 DBG(cdev, "reset generic ttyGS%d\n", gser->port_num);
 139                 gserial_disconnect(&gser->port);
 140         } else {
 141                 DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
 142                 gser->port.in_desc = ep_choose(cdev->gadget,
 143                                 gser->hs.in, gser->fs.in);
 144                 gser->port.out_desc = ep_choose(cdev->gadget,
 145                                 gser->hs.out, gser->fs.out);
 146         }
 147         gserial_connect(&gser->port, gser->port_num);
 148         return 0;
 149 }
 150
 151 static void gser_disable(struct usb_function *f)
 152 {
 153         struct f_gser   *gser = func_to_gser(f);
 154         struct usb_composite_dev *cdev = f->config->cdev;
 155
 156         DBG(cdev, "generic ttyGS%d deactivated\n", gser->port_num);
 157         gserial_disconnect(&gser->port);
 158 }
 159
 160 /*-------------------------------------------------------------------------*/
 161
 162 /* serial function driver setup/binding */
 163
 164 static int __init
 165 gser_bind(struct usb_configuration *c, struct usb_function *f)
 166 {
 167         struct usb_composite_dev *cdev = c->cdev;
 168         struct f_gser           *gser = func_to_gser(f);
 169         int                     status;
 170         struct usb_ep           *ep;
 171
 172         /* allocate instance-specific interface IDs */
 173         status = usb_interface_id(c, f);
 174         if (status < 0)
 175                 goto fail;
 176         gser->data_id = status;
 177         gser_interface_desc.bInterfaceNumber = status;
 178
 179         status = -ENODEV;
 180
 181         /* allocate instance-specific endpoints */
 182         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 183         if (!ep)
 184                 goto fail;
 185         gser->port.in = ep;
 186         ep->driver_data = cdev; /* claim */
 187
 188         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 189         if (!ep)
 190                 goto fail;
 191         gser->port.out = ep;
 192         ep->driver_data = cdev; /* claim */
 193
 194         /* copy descriptors, and track endpoint copies */
 195         f->descriptors = usb_copy_descriptors(gser_fs_function);
 196
 197         gser->fs.in = usb_find_endpoint(gser_fs_function,
 198                         f->descriptors, &gser_fs_in_desc);
 199         gser->fs.out = usb_find_endpoint(gser_fs_function,
 200                         f->descriptors, &gser_fs_out_desc);
 201
 202
 203         /* support all relevant hardware speeds... we expect that when
 204          * hardware is dual speed, all bulk-capable endpoints work at
 205          * both speeds
 206          */
 207         if (gadget_is_dualspeed(c->cdev->gadget)) {
 208                 gser_hs_in_desc.bEndpointAddress =
 209                                 gser_fs_in_desc.bEndpointAddress;
 210                 gser_hs_out_desc.bEndpointAddress =
 211                                 gser_fs_out_desc.bEndpointAddress;
 212
 213                 /* copy descriptors, and track endpoint copies */
 214                 f->hs_descriptors = usb_copy_descriptors(gser_hs_function);
 215
 216                 gser->hs.in = usb_find_endpoint(gser_hs_function,
 217                                 f->hs_descriptors, &gser_hs_in_desc);
 218                 gser->hs.out = usb_find_endpoint(gser_hs_function,
 219                                 f->hs_descriptors, &gser_hs_out_desc);
 220         }
 221
 222         DBG(cdev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
 223                         gser->port_num,
 224                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 225                         gser->port.in->name, gser->port.out->name);
 226         return 0;
 227
 228 fail:
 229         /* we might as well release our claims on endpoints */
 230         if (gser->port.out)
 231                 gser->port.out->driver_data = NULL;
 232         if (gser->port.in)
 233                 gser->port.in->driver_data = NULL;
 234
 235         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 236
 237         return status;
 238 }
 239
 240 static void
 241 gser_unbind(struct usb_configuration *c, struct usb_function *f)
 242 {
 243         if (gadget_is_dualspeed(c->cdev->gadget))
 244                 usb_free_descriptors(f->hs_descriptors);
 245         usb_free_descriptors(f->descriptors);
 246         kfree(func_to_gser(f));
 247 }
 248
 249 /**
 250  * gser_bind_config - add a generic serial function to a configuration
 251  * @c: the configuration to support the serial instance
 252  * @port_num: /dev/ttyGS* port this interface will use
 253  * Context: single threaded during gadget setup
 254  *
 255  * Returns zero on success, else negative errno.
 256  *
 257  * Caller must have called @gserial_setup() with enough ports to
 258  * handle all the ones it binds.  Caller is also responsible
 259  * for calling @gserial_cleanup() before module unload.
 260  */
 261 int __init gser_bind_config(struct usb_configuration *c, u8 port_num)
 262 {
 263         struct f_gser   *gser;
 264         int             status;
 265
 266         /* REVISIT might want instance-specific strings to help
 267          * distinguish instances ...
 268          */
 269
 270         /* maybe allocate device-global string ID */
 271         if (gser_string_defs[0].id == 0) {
 272                 status = usb_string_id(c->cdev);
 273                 if (status < 0)
 274                         return status;
 275                 gser_string_defs[0].id = status;
 276         }
 277
 278         /* allocate and initialize one new instance */
 279         gser = kzalloc(sizeof *gser, GFP_KERNEL);
 280         if (!gser)
 281                 return -ENOMEM;
 282
 283         gser->port_num = port_num;
 284
 285         gser->port.func.name = "gser";
 286         gser->port.func.strings = gser_strings;
 287         gser->port.func.bind = gser_bind;
 288         gser->port.func.unbind = gser_unbind;
 289         gser->port.func.set_alt = gser_set_alt;
 290         gser->port.func.disable = gser_disable;
 291
 292         status = usb_add_function(c, &gser->port.func);
 293         if (status)
 294                 kfree(gser);
 295         return status;
 296 }