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 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 __initdata = {
  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 __initdata = {
  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 __initdata = {
  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[] __initdata = {
  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 __initdata = {
  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 __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_descriptor_header *gser_hs_function[] __initdata = {
  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 /* string descriptors: */
 103
 104 static struct usb_string gser_string_defs[] = {
 105         [0].s = "Generic Serial",
 106         {  } /* end of list */
 107 };
 108
 109 static struct usb_gadget_strings gser_string_table = {
 110         .language =             0x0409, /* en-us */
 111         .strings =              gser_string_defs,
 112 };
 113
 114 static struct usb_gadget_strings *gser_strings[] = {
 115         &gser_string_table,
 116         NULL,
 117 };
 118
 119 /*-------------------------------------------------------------------------*/
 120
 121 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 122 {
 123         struct f_gser           *gser = func_to_gser(f);
 124         struct usb_composite_dev *cdev = f->config->cdev;
 125
 126         /* we know alt == 0, so this is an activation or a reset */
 127
 128         if (gser->port.in->driver_data) {
 129                 DBG(cdev, "reset generic ttyGS%d\n", gser->port_num);
 130                 gserial_disconnect(&gser->port);
 131         }
 132         if (!gser->port.in->desc || !gser->port.out->desc) {
 133                 DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
 134                 if (!config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
 135                     !config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
 136                         gser->port.in->desc = NULL;
 137                         gser->port.out->desc = NULL;
 138                         return -EINVAL;
 139                 }
 140         }
 141         gserial_connect(&gser->port, gser->port_num);
 142         return 0;
 143 }
 144
 145 static void gser_disable(struct usb_function *f)
 146 {
 147         struct f_gser   *gser = func_to_gser(f);
 148         struct usb_composite_dev *cdev = f->config->cdev;
 149
 150         DBG(cdev, "generic ttyGS%d deactivated\n", gser->port_num);
 151         gserial_disconnect(&gser->port);
 152 }
 153
 154 /*-------------------------------------------------------------------------*/
 155
 156 /* serial function driver setup/binding */
 157
 158 static int __init
 159 gser_bind(struct usb_configuration *c, struct usb_function *f)
 160 {
 161         struct usb_composite_dev *cdev = c->cdev;
 162         struct f_gser           *gser = func_to_gser(f);
 163         int                     status;
 164         struct usb_ep           *ep;
 165
 166         /* allocate instance-specific interface IDs */
 167         status = usb_interface_id(c, f);
 168         if (status < 0)
 169                 goto fail;
 170         gser->data_id = status;
 171         gser_interface_desc.bInterfaceNumber = status;
 172
 173         status = -ENODEV;
 174
 175         /* allocate instance-specific endpoints */
 176         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 177         if (!ep)
 178                 goto fail;
 179         gser->port.in = ep;
 180         ep->driver_data = cdev; /* claim */
 181
 182         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 183         if (!ep)
 184                 goto fail;
 185         gser->port.out = ep;
 186         ep->driver_data = cdev; /* claim */
 187
 188         /* copy descriptors, and track endpoint copies */
 189         f->descriptors = usb_copy_descriptors(gser_fs_function);
 190
 191         /* support all relevant hardware speeds... we expect that when
 192          * hardware is dual speed, all bulk-capable endpoints work at
 193          * both speeds
 194          */
 195         if (gadget_is_dualspeed(c->cdev->gadget)) {
 196                 gser_hs_in_desc.bEndpointAddress =
 197                                 gser_fs_in_desc.bEndpointAddress;
 198                 gser_hs_out_desc.bEndpointAddress =
 199                                 gser_fs_out_desc.bEndpointAddress;
 200
 201                 /* copy descriptors, and track endpoint copies */
 202                 f->hs_descriptors = usb_copy_descriptors(gser_hs_function);
 203         }
 204
 205         DBG(cdev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
 206                         gser->port_num,
 207                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 208                         gser->port.in->name, gser->port.out->name);
 209         return 0;
 210
 211 fail:
 212         /* we might as well release our claims on endpoints */
 213         if (gser->port.out)
 214                 gser->port.out->driver_data = NULL;
 215         if (gser->port.in)
 216                 gser->port.in->driver_data = NULL;
 217
 218         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 219
 220         return status;
 221 }
 222
 223 static void
 224 gser_unbind(struct usb_configuration *c, struct usb_function *f)
 225 {
 226         if (gadget_is_dualspeed(c->cdev->gadget))
 227                 usb_free_descriptors(f->hs_descriptors);
 228         usb_free_descriptors(f->descriptors);
 229         kfree(func_to_gser(f));
 230 }
 231
 232 /**
 233  * gser_bind_config - add a generic serial function to a configuration
 234  * @c: the configuration to support the serial instance
 235  * @port_num: /dev/ttyGS* port this interface will use
 236  * Context: single threaded during gadget setup
 237  *
 238  * Returns zero on success, else negative errno.
 239  *
 240  * Caller must have called @gserial_setup() with enough ports to
 241  * handle all the ones it binds.  Caller is also responsible
 242  * for calling @gserial_cleanup() before module unload.
 243  */
 244 int __init gser_bind_config(struct usb_configuration *c, u8 port_num)
 245 {
 246         struct f_gser   *gser;
 247         int             status;
 248
 249         /* REVISIT might want instance-specific strings to help
 250          * distinguish instances ...
 251          */
 252
 253         /* maybe allocate device-global string ID */
 254         if (gser_string_defs[0].id == 0) {
 255                 status = usb_string_id(c->cdev);
 256                 if (status < 0)
 257                         return status;
 258                 gser_string_defs[0].id = status;
 259         }
 260
 261         /* allocate and initialize one new instance */
 262         gser = kzalloc(sizeof *gser, GFP_KERNEL);
 263         if (!gser)
 264                 return -ENOMEM;
 265
 266         gser->port_num = port_num;
 267
 268         gser->port.func.name = "gser";
 269         gser->port.func.strings = gser_strings;
 270         gser->port.func.bind = gser_bind;
 271         gser->port.func.unbind = gser_unbind;
 272         gser->port.func.set_alt = gser_set_alt;
 273         gser->port.func.disable = gser_disable;
 274
 275         status = usb_add_function(c, &gser->port.func);
 276         if (status)
 277                 kfree(gser);
 278         return status;
 279 }