f_obex.c

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/*
 * f_obex.c -- USB CDC OBEX function driver
 *
 * Copyright (C) 2008 Nokia Corporation
 * Contact: Felipe Balbi <[email protected]>
 *
 * Based on f_acm.c by Al Borchers and David Brownell.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/* #define VERBOSE_DEBUG */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>

#include "u_serial.h"
#include "gadget_chips.h"


/*
 * This CDC OBEX function support just packages a TTY-ish byte stream.
 * A user mode server will put it into "raw" mode and handle all the
 * relevant protocol details ... this is just a kernel passthrough.
 * When possible, we prevent gadget enumeration until that server is
 * ready to handle the commands.
 */

struct f_obex {
    struct gserial          port;
    u8              ctrl_id;
    u8              data_id;
    u8              port_num;
    u8              can_activate;
};

static inline struct f_obex *func_to_obex(struct usb_function *f)
{
    return container_of(f, struct f_obex, port.func);
}

static inline struct f_obex *port_to_obex(struct gserial *p)
{
    return container_of(p, struct f_obex, port);
}

/*-------------------------------------------------------------------------*/

#define OBEX_CTRL_IDX   0
#define OBEX_DATA_IDX   1

static struct usb_string obex_string_defs[] = {
    [OBEX_CTRL_IDX].s   = "CDC Object Exchange (OBEX)",
    [OBEX_DATA_IDX].s   = "CDC OBEX Data",
    {  },   /* end of list */
};

static struct usb_gadget_strings obex_string_table = {
    .language       = 0x0409,   /* en-US */
    .strings        = obex_string_defs,
};

static struct usb_gadget_strings *obex_strings[] = {
    &obex_string_table,
    NULL,
};

/*-------------------------------------------------------------------------*/

static struct usb_interface_descriptor obex_control_intf __initdata = {
    .bLength        = sizeof(obex_control_intf),
    .bDescriptorType    = USB_DT_INTERFACE,
    .bInterfaceNumber   = 0,

    .bAlternateSetting  = 0,
    .bNumEndpoints      = 0,
    .bInterfaceClass    = USB_CLASS_COMM,
    .bInterfaceSubClass = USB_CDC_SUBCLASS_OBEX,
};

static struct usb_interface_descriptor obex_data_nop_intf __initdata = {
    .bLength        = sizeof(obex_data_nop_intf),
    .bDescriptorType    = USB_DT_INTERFACE,
    .bInterfaceNumber   = 1,

    .bAlternateSetting  = 0,
    .bNumEndpoints      = 0,
    .bInterfaceClass    = USB_CLASS_CDC_DATA,
};

static struct usb_interface_descriptor obex_data_intf __initdata = {
    .bLength        = sizeof(obex_data_intf),
    .bDescriptorType    = USB_DT_INTERFACE,
    .bInterfaceNumber   = 2,

    .bAlternateSetting  = 1,
    .bNumEndpoints      = 2,
    .bInterfaceClass    = USB_CLASS_CDC_DATA,
};

static struct usb_cdc_header_desc obex_cdc_header_desc __initdata = {
    .bLength        = sizeof(obex_cdc_header_desc),
    .bDescriptorType    = USB_DT_CS_INTERFACE,
    .bDescriptorSubType = USB_CDC_HEADER_TYPE,
    .bcdCDC         = cpu_to_le16(0x0120),
};

static struct usb_cdc_union_desc obex_cdc_union_desc __initdata = {
    .bLength        = sizeof(obex_cdc_union_desc),
    .bDescriptorType    = USB_DT_CS_INTERFACE,
    .bDescriptorSubType = USB_CDC_UNION_TYPE,
    .bMasterInterface0  = 1,
    .bSlaveInterface0   = 2,
};

static struct usb_cdc_obex_desc obex_desc __initdata = {
    .bLength        = sizeof(obex_desc),
    .bDescriptorType    = USB_DT_CS_INTERFACE,
    .bDescriptorSubType = USB_CDC_OBEX_TYPE,
    .bcdVersion     = cpu_to_le16(0x0100),
};

/* High-Speed Support */

static struct usb_endpoint_descriptor obex_hs_ep_out_desc __initdata = {
    .bLength        = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_ENDPOINT,

    .bEndpointAddress   = USB_DIR_OUT,
    .bmAttributes       = USB_ENDPOINT_XFER_BULK,
    .wMaxPacketSize     = cpu_to_le16(512),
};

static struct usb_endpoint_descriptor obex_hs_ep_in_desc __initdata = {
    .bLength        = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_ENDPOINT,

    .bEndpointAddress   = USB_DIR_IN,
    .bmAttributes       = USB_ENDPOINT_XFER_BULK,
    .wMaxPacketSize     = cpu_to_le16(512),
};

static struct usb_descriptor_header *hs_function[] __initdata = {
    (struct usb_descriptor_header *) &obex_control_intf,
    (struct usb_descriptor_header *) &obex_cdc_header_desc,
    (struct usb_descriptor_header *) &obex_desc,
    (struct usb_descriptor_header *) &obex_cdc_union_desc,

    (struct usb_descriptor_header *) &obex_data_nop_intf,
    (struct usb_descriptor_header *) &obex_data_intf,
    (struct usb_descriptor_header *) &obex_hs_ep_in_desc,
    (struct usb_descriptor_header *) &obex_hs_ep_out_desc,
    NULL,
};

/* Full-Speed Support */

static struct usb_endpoint_descriptor obex_fs_ep_in_desc __initdata = {
    .bLength        = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_ENDPOINT,

    .bEndpointAddress   = USB_DIR_IN,
    .bmAttributes       = USB_ENDPOINT_XFER_BULK,
};

static struct usb_endpoint_descriptor obex_fs_ep_out_desc __initdata = {
    .bLength        = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_ENDPOINT,

    .bEndpointAddress   = USB_DIR_OUT,
    .bmAttributes       = USB_ENDPOINT_XFER_BULK,
};

static struct usb_descriptor_header *fs_function[] __initdata = {
    (struct usb_descriptor_header *) &obex_control_intf,
    (struct usb_descriptor_header *) &obex_cdc_header_desc,
    (struct usb_descriptor_header *) &obex_desc,
    (struct usb_descriptor_header *) &obex_cdc_union_desc,

    (struct usb_descriptor_header *) &obex_data_nop_intf,
    (struct usb_descriptor_header *) &obex_data_intf,
    (struct usb_descriptor_header *) &obex_fs_ep_in_desc,
    (struct usb_descriptor_header *) &obex_fs_ep_out_desc,
    NULL,
};

/*-------------------------------------------------------------------------*/

static int obex_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
    struct f_obex       *obex = func_to_obex(f);
    struct usb_composite_dev *cdev = f->config->cdev;

    if (intf == obex->ctrl_id) {
        if (alt != 0)
            goto fail;
        /* NOP */
        DBG(cdev, "reset obex ttyGS%d control\n", obex->port_num);

    } else if (intf == obex->data_id) {
        if (alt > 1)
            goto fail;

        if (obex->port.in->driver_data) {
            DBG(cdev, "reset obex ttyGS%d\n", obex->port_num);
            gserial_disconnect(&obex->port);
        }

        if (!obex->port.in->desc || !obex->port.out->desc) {
            DBG(cdev, "init obex ttyGS%d\n", obex->port_num);
            if (config_ep_by_speed(cdev->gadget, f,
                           obex->port.in) ||
                config_ep_by_speed(cdev->gadget, f,
                           obex->port.out)) {
                obex->port.out->desc = NULL;
                obex->port.in->desc = NULL;
                goto fail;
            }
        }

        if (alt == 1) {
            DBG(cdev, "activate obex ttyGS%d\n", obex->port_num);
            gserial_connect(&obex->port, obex->port_num);
        }

    } else
        goto fail;

    return 0;

fail:
    return -EINVAL;
}

static int obex_get_alt(struct usb_function *f, unsigned intf)
{
    struct f_obex       *obex = func_to_obex(f);

    if (intf == obex->ctrl_id)
        return 0;

    return obex->port.in->driver_data ? 1 : 0;
}

static void obex_disable(struct usb_function *f)
{
    struct f_obex   *obex = func_to_obex(f);
    struct usb_composite_dev *cdev = f->config->cdev;

    DBG(cdev, "obex ttyGS%d disable\n", obex->port_num);
    gserial_disconnect(&obex->port);
}

/*-------------------------------------------------------------------------*/

static void obex_connect(struct gserial *g)
{
    struct f_obex       *obex = port_to_obex(g);
    struct usb_composite_dev *cdev = g->func.config->cdev;
    int         status;

    if (!obex->can_activate)
        return;

    status = usb_function_activate(&g->func);
    if (status)
        DBG(cdev, "obex ttyGS%d function activate --> %d\n",
            obex->port_num, status);
}

static void obex_disconnect(struct gserial *g)
{
    struct f_obex       *obex = port_to_obex(g);
    struct usb_composite_dev *cdev = g->func.config->cdev;
    int         status;

    if (!obex->can_activate)
        return;

    status = usb_function_deactivate(&g->func);
    if (status)
        DBG(cdev, "obex ttyGS%d function deactivate --> %d\n",
            obex->port_num, status);
}

/*-------------------------------------------------------------------------*/

static int __init
obex_bind(struct usb_configuration *c, struct usb_function *f)
{
    struct usb_composite_dev *cdev = c->cdev;
    struct f_obex       *obex = func_to_obex(f);
    int         status;
    struct usb_ep       *ep;

    /* allocate instance-specific interface IDs, and patch descriptors */

    status = usb_interface_id(c, f);
    if (status < 0)
        goto fail;
    obex->ctrl_id = status;

    obex_control_intf.bInterfaceNumber = status;
    obex_cdc_union_desc.bMasterInterface0 = status;

    status = usb_interface_id(c, f);
    if (status < 0)
        goto fail;
    obex->data_id = status;

    obex_data_nop_intf.bInterfaceNumber = status;
    obex_data_intf.bInterfaceNumber = status;
    obex_cdc_union_desc.bSlaveInterface0 = status;

    /* allocate instance-specific endpoints */

    ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_in_desc);
    if (!ep)
        goto fail;
    obex->port.in = ep;
    ep->driver_data = cdev; /* claim */

    ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_out_desc);
    if (!ep)
        goto fail;
    obex->port.out = ep;
    ep->driver_data = cdev; /* claim */

    /* copy descriptors, and track endpoint copies */
    f->descriptors = usb_copy_descriptors(fs_function);

    /* support all relevant hardware speeds... we expect that when
     * hardware is dual speed, all bulk-capable endpoints work at
     * both speeds
     */
    if (gadget_is_dualspeed(c->cdev->gadget)) {

        obex_hs_ep_in_desc.bEndpointAddress =
                obex_fs_ep_in_desc.bEndpointAddress;
        obex_hs_ep_out_desc.bEndpointAddress =
                obex_fs_ep_out_desc.bEndpointAddress;

        /* copy descriptors, and track endpoint copies */
        f->hs_descriptors = usb_copy_descriptors(hs_function);
    }

    /* Avoid letting this gadget enumerate until the userspace
     * OBEX server is active.
     */
    status = usb_function_deactivate(f);
    if (status < 0)
        WARNING(cdev, "obex ttyGS%d: can't prevent enumeration, %d\n",
            obex->port_num, status);
    else
        obex->can_activate = true;


    DBG(cdev, "obex ttyGS%d: %s speed IN/%s OUT/%s\n",
            obex->port_num,
            gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
            obex->port.in->name, obex->port.out->name);

    return 0;

fail:
    /* we might as well release our claims on endpoints */
    if (obex->port.out)
        obex->port.out->driver_data = NULL;
    if (obex->port.in)
        obex->port.in->driver_data = NULL;

    ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);

    return status;
}

static void
obex_unbind(struct usb_configuration *c, struct usb_function *f)
{
    if (gadget_is_dualspeed(c->cdev->gadget))
        usb_free_descriptors(f->hs_descriptors);
    usb_free_descriptors(f->descriptors);
    kfree(func_to_obex(f));
}

/* Some controllers can't support CDC OBEX ... */
static inline bool can_support_obex(struct usb_configuration *c)
{
    /* Since the first interface is a NOP, we can ignore the
     * issue of multi-interface support on most controllers.
     *
     * Altsettings are mandatory, however...
     */
    if (!gadget_supports_altsettings(c->cdev->gadget))
        return false;

    /* everything else is *probably* fine ... */
    return true;
}

int __init obex_bind_config(struct usb_configuration *c, u8 port_num)
{
    struct f_obex   *obex;
    int     status;

    if (!can_support_obex(c))
        return -EINVAL;

    /* maybe allocate device-global string IDs, and patch descriptors */
    if (obex_string_defs[OBEX_CTRL_IDX].id == 0) {
        status = usb_string_id(c->cdev);
        if (status < 0)
            return status;
        obex_string_defs[OBEX_CTRL_IDX].id = status;

        obex_control_intf.iInterface = status;

        status = usb_string_id(c->cdev);
        if (status < 0)
            return status;
        obex_string_defs[OBEX_DATA_IDX].id = status;

        obex_data_nop_intf.iInterface =
            obex_data_intf.iInterface = status;
    }

    /* allocate and initialize one new instance */
    obex = kzalloc(sizeof *obex, GFP_KERNEL);
    if (!obex)
        return -ENOMEM;

    obex->port_num = port_num;

    obex->port.connect = obex_connect;
    obex->port.disconnect = obex_disconnect;

    obex->port.func.name = "obex";
    obex->port.func.strings = obex_strings;
    /* descriptors are per-instance copies */
    obex->port.func.bind = obex_bind;
    obex->port.func.unbind = obex_unbind;
    obex->port.func.set_alt = obex_set_alt;
    obex->port.func.get_alt = obex_get_alt;
    obex->port.func.disable = obex_disable;

    status = usb_add_function(c, &obex->port.func);
    if (status)
        kfree(obex);

    return status;
}

MODULE_AUTHOR("Felipe Balbi");
MODULE_LICENSE("GPL");