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 static struct usb_endpoint_descriptor gser_ss_in_desc __initdata = {
 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 __initdata = {
 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 __initdata = {
 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[] __initdata = {
 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->driver_data) {
 157                 DBG(cdev, "reset generic ttyGS%d\n", gser->port_num);
 158                 gserial_disconnect(&gser->port);
 159         }
 160         if (!gser->port.in->desc || !gser->port.out->desc) {
 161                 DBG(cdev, "activate generic ttyGS%d\n", gser->port_num);
 162                 if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
 163                     config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
 164                         gser->port.in->desc = NULL;
 165                         gser->port.out->desc = NULL;
 166                         return -EINVAL;
 167                 }
 168         }
 169         gserial_connect(&gser->port, gser->port_num);
 170         return 0;
 171 }
 172
 173 static void gser_disable(struct usb_function *f)
 174 {
 175         struct f_gser   *gser = func_to_gser(f);
 176         struct usb_composite_dev *cdev = f->config->cdev;
 177
 178         DBG(cdev, "generic ttyGS%d deactivated\n", gser->port_num);
 179         gserial_disconnect(&gser->port);
 180 }
 181
 182 /*-------------------------------------------------------------------------*/
 183
 184 /* serial function driver setup/binding */
 185
 186 static int __init
 187 gser_bind(struct usb_configuration *c, struct usb_function *f)
 188 {
 189         struct usb_composite_dev *cdev = c->cdev;
 190         struct f_gser           *gser = func_to_gser(f);
 191         int                     status;
 192         struct usb_ep           *ep;
 193
 194         /* allocate instance-specific interface IDs */
 195         status = usb_interface_id(c, f);
 196         if (status < 0)
 197                 goto fail;
 198         gser->data_id = status;
 199         gser_interface_desc.bInterfaceNumber = status;
 200
 201         status = -ENODEV;
 202
 203         /* allocate instance-specific endpoints */
 204         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 205         if (!ep)
 206                 goto fail;
 207         gser->port.in = ep;
 208         ep->driver_data = cdev; /* claim */
 209
 210         ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 211         if (!ep)
 212                 goto fail;
 213         gser->port.out = ep;
 214         ep->driver_data = cdev; /* claim */
 215
 216         /* support all relevant hardware speeds... we expect that when
 217          * hardware is dual speed, all bulk-capable endpoints work at
 218          * both speeds
 219          */
 220         gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 221         gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
 222
 223         gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 224         gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
 225
 226         status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
 227                         gser_ss_function);
 228         if (status)
 229                 goto fail;
 230         DBG(cdev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
 231                         gser->port_num,
 232                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 233                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 234                         gser->port.in->name, gser->port.out->name);
 235         return 0;
 236
 237 fail:
 238         /* we might as well release our claims on endpoints */
 239         if (gser->port.out)
 240                 gser->port.out->driver_data = NULL;
 241         if (gser->port.in)
 242                 gser->port.in->driver_data = NULL;
 243
 244         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 245
 246         return status;
 247 }
 248
 249 static void
 250 gser_unbind(struct usb_configuration *c, struct usb_function *f)
 251 {
 252         usb_free_all_descriptors(f);
 253         kfree(func_to_gser(f));
 254 }
 255
 256 /**
 257  * gser_bind_config - add a generic serial function to a configuration
 258  * @c: the configuration to support the serial instance
 259  * @port_num: /dev/ttyGS* port this interface will use
 260  * Context: single threaded during gadget setup
 261  *
 262  * Returns zero on success, else negative errno.
 263  */
 264 int __init gser_bind_config(struct usb_configuration *c, u8 port_num)
 265 {
 266         struct f_gser   *gser;
 267         int             status;
 268
 269         /* REVISIT might want instance-specific strings to help
 270          * distinguish instances ...
 271          */
 272
 273         /* maybe allocate device-global string ID */
 274         if (gser_string_defs[0].id == 0) {
 275                 status = usb_string_id(c->cdev);
 276                 if (status < 0)
 277                         return status;
 278                 gser_string_defs[0].id = status;
 279         }
 280
 281         /* allocate and initialize one new instance */
 282         gser = kzalloc(sizeof *gser, GFP_KERNEL);
 283         if (!gser)
 284                 return -ENOMEM;
 285
 286         gser->port_num = port_num;
 287
 288         gser->port.func.name = "gser";
 289         gser->port.func.strings = gser_strings;
 290         gser->port.func.bind = gser_bind;
 291         gser->port.func.unbind = gser_unbind;
 292         gser->port.func.set_alt = gser_set_alt;
 293         gser->port.func.disable = gser_disable;
 294
 295         status = usb_add_function(c, &gser->port.func);
 296         if (status)
 297                 kfree(gser);
 298         return status;
 299 }