usbnet.c

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/*
 * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <string.h>
#include <errno.h>
#include <ipxe/usb.h>
#include <ipxe/usbnet.h>

/** @file
 *
 * USB network devices
 *
 * USB network devices use a variety of packet formats and interface
 * descriptors, but tend to have several features in common:
 *
 *  - a single bulk OUT endpoint
 *
 *  - a single bulk IN endpoint using the generic refill mechanism
 *
 *  - an optional interrupt endpoint using the generic refill mechanism
 *
 *  - optional use of an alternate setting to enable the data interface
 *
 */

/**
 * Open USB network device
 *
 * @v usbnet            USB network device
 * @ret rc              Return status code
 */
int usbnet_open ( struct usbnet_device *usbnet ) {
        struct usb_device *usb = usbnet->func->usb;
        int rc;

        /* Open interrupt endpoint, if applicable */
        if ( usbnet_has_intr ( usbnet ) &&
             ( rc = usb_endpoint_open ( &usbnet->intr ) ) != 0 ) {
                DBGC ( usbnet, "USBNET %s could not open interrupt: %s\n",
                       usbnet->func->name, strerror ( rc ) );
                goto err_open_intr;
        }

        /* Refill interrupt endpoint, if applicable */
        if ( usbnet_has_intr ( usbnet ) &&
             ( rc = usb_refill ( &usbnet->intr ) ) != 0 ) {
                DBGC ( usbnet, "USBNET %s could not refill interrupt: %s\n",
                       usbnet->func->name, strerror ( rc ) );
                goto err_refill_intr;
        }

        /* Select alternate setting for data interface, if applicable */
        if ( usbnet->alternate &&
             ( ( rc = usb_set_interface ( usb, usbnet->data,
                                          usbnet->alternate ) ) != 0 ) ) {
                DBGC ( usbnet, "USBNET %s could not set alternate interface "
                       "%d: %s\n", usbnet->func->name, usbnet->alternate,
                       strerror ( rc ) );
                goto err_set_interface;
        }

        /* Open bulk IN endpoint */
        if ( ( rc = usb_endpoint_open ( &usbnet->in ) ) != 0 ) {
                DBGC ( usbnet, "USBNET %s could not open bulk IN: %s\n",
                       usbnet->func->name, strerror ( rc ) );
                goto err_open_in;
        }

        /* Open bulk OUT endpoint */
        if ( ( rc = usb_endpoint_open ( &usbnet->out ) ) != 0 ) {
                DBGC ( usbnet, "USBNET %s could not open bulk OUT: %s\n",
                       usbnet->func->name, strerror ( rc ) );
                goto err_open_out;
        }

        /* Refill bulk IN endpoint */
        if ( ( rc = usb_refill ( &usbnet->in ) ) != 0 ) {
                DBGC ( usbnet, "USBNET %s could not refill bulk IN: %s\n",
                       usbnet->func->name, strerror ( rc ) );
                goto err_refill_in;
        }

        return 0;

 err_refill_in:
        usb_endpoint_close ( &usbnet->out );
 err_open_out:
        usb_endpoint_close ( &usbnet->in );
 err_open_in:
        if ( usbnet->alternate )
                usb_set_interface ( usb, usbnet->data, 0 );
 err_set_interface:
 err_refill_intr:
        if ( usbnet_has_intr ( usbnet ) )
                usb_endpoint_close ( &usbnet->intr );
 err_open_intr:
        return rc;
}

/**
 * Close USB network device
 *
 * @v usbnet            USB network device
 */
void usbnet_close ( struct usbnet_device *usbnet ) {
        struct usb_device *usb = usbnet->func->usb;

        /* Close bulk OUT endpoint */
        usb_endpoint_close ( &usbnet->out );

        /* Close bulk IN endpoint */
        usb_endpoint_close ( &usbnet->in );

        /* Reset alternate setting for data interface, if applicable */
        if ( usbnet->alternate )
                usb_set_interface ( usb, usbnet->data, 0 );

        /* Close interrupt endpoint, if applicable */
        if ( usbnet_has_intr ( usbnet ) )
                usb_endpoint_close ( &usbnet->intr );
}

/**
 * Refill USB network device bulk IN and interrupt endpoints
 *
 * @v usbnet            USB network device
 * @ret rc              Return status code
 */
int usbnet_refill ( struct usbnet_device *usbnet ) {
        int rc;

        /* Refill bulk IN endpoint */
        if ( ( rc = usb_refill ( &usbnet->in ) ) != 0 )
                return rc;

        /* Refill interrupt endpoint, if applicable */
        if ( usbnet_has_intr ( usbnet ) &&
             ( rc = usb_refill ( &usbnet->intr ) ) != 0 ) {
                return rc;
        }

        return 0;
}

/**
 * Describe communications interface and interrupt endpoint
 *
 * @v usbnet            USB network device
 * @v config            Configuration descriptor
 * @ret rc              Return status code
 */
static int usbnet_comms_describe ( struct usbnet_device *usbnet,
                                   struct usb_configuration_descriptor *config){
        struct usb_interface_descriptor *desc;
        unsigned int comms;
        unsigned int i;
        int rc;

        /* Iterate over all available interfaces */
        for ( i = 0 ; i < usbnet->func->desc.count ; i++ ) {

                /* Get interface number */
                comms = usbnet->func->interface[i];

                /* Locate interface descriptor */
                desc = usb_interface_descriptor ( config, comms, 0 );
                if ( ! desc )
                        continue;

                /* Describe interrupt endpoint */
                if ( ( rc = usb_endpoint_described ( &usbnet->intr, config,
                                                     desc, USB_INTERRUPT_IN,
                                                     0 ) ) != 0 )
                        continue;

                /* Record communications interface */
                usbnet->comms = comms;
                DBGC ( usbnet, "USBNET %s found communications interface %d\n",
                       usbnet->func->name, comms );
                return 0;
        }

        DBGC ( usbnet, "USBNET %s found no communications interface\n",
               usbnet->func->name );
        return -ENOENT;
}

/**
 * Describe data interface and bulk endpoints
 *
 * @v usbnet            USB network device
 * @v config            Configuration descriptor
 * @ret rc              Return status code
 */
static int usbnet_data_describe ( struct usbnet_device *usbnet,
                                  struct usb_configuration_descriptor *config ){
        struct usb_interface_descriptor *desc;
        unsigned int data;
        unsigned int alt;
        unsigned int i;
        int rc;

        /* Iterate over all available interfaces */
        for ( i = 0 ; i < usbnet->func->desc.count ; i++ ) {

                /* Get interface number */
                data = usbnet->func->interface[i];

                /* Iterate over all existent alternate settings */
                for ( alt = 0 ; ; alt++ ) {

                        /* Locate interface descriptor */
                        desc = usb_interface_descriptor ( config, data, alt );
                        if ( ! desc )
                                break;

                        /* Describe bulk IN endpoint */
                        if ( ( rc = usb_endpoint_described ( &usbnet->in,
                                                             config, desc,
                                                             USB_BULK_IN,
                                                             0 ) ) != 0 )
                                continue;

                        /* Describe bulk OUT endpoint */
                        if ( ( rc = usb_endpoint_described ( &usbnet->out,
                                                             config, desc,
                                                             USB_BULK_OUT,
                                                             0 ) ) != 0 )
                                continue;

                        /* Record data interface and alternate setting */
                        usbnet->data = data;
                        usbnet->alternate = alt;
                        DBGC ( usbnet, "USBNET %s found data interface %d",
                               usbnet->func->name, data );
                        if ( alt )
                                DBGC ( usbnet, " using alternate %d", alt );
                        DBGC ( usbnet, "\n" );
                        return 0;
                }
        }

        DBGC ( usbnet, "USBNET %s found no data interface\n",
               usbnet->func->name );
        return -ENOENT;
}

/**
 * Describe USB network device interfaces
 *
 * @v usbnet            USB network device
 * @v config            Configuration descriptor
 * @ret rc              Return status code
 */
int usbnet_describe ( struct usbnet_device *usbnet,
                      struct usb_configuration_descriptor *config ) {
        int rc;

        /* Describe communications interface, if applicable */
        if ( usbnet_has_intr ( usbnet ) &&
             ( rc = usbnet_comms_describe ( usbnet, config ) ) != 0 ) {
                return rc;
        }

        /* Describe data interface */
        if ( ( rc = usbnet_data_describe ( usbnet, config ) ) != 0 )
                return rc;

        return 0;
}