ecm.c

Go to the documentation of this file.

/*
 * Copyright (C) 2014 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 );
FILE_SECBOOT ( PERMITTED );

#include <stdint.h>
#include <errno.h>
#include <ipxe/netdevice.h>
#include <ipxe/ethernet.h>
#include <ipxe/if_ether.h>
#include <ipxe/base16.h>
#include <ipxe/profile.h>
#include <ipxe/acpimac.h>
#include <ipxe/usb.h>
#include "ecm.h"

/** @file
 *
 * CDC-ECM USB Ethernet driver
 *
 */

/** Interrupt completion profiler */
static struct profiler ecm_intr_profiler __profiler =
        { .name = "ecm.intr" };

/** Bulk IN completion profiler */
static struct profiler ecm_in_profiler __profiler =
        { .name = "ecm.in" };

/** Bulk OUT profiler */
static struct profiler ecm_out_profiler __profiler =
        { .name = "ecm.out" };

/******************************************************************************
 *
 * Ethernet functional descriptor
 *
 ******************************************************************************
 */

/**
 * Locate Ethernet functional descriptor
 *
 * @v config            Configuration descriptor
 * @v interface         Interface descriptor
 * @ret desc            Descriptor, or NULL if not found
 */
struct ecm_ethernet_descriptor *
ecm_ethernet_descriptor ( struct usb_configuration_descriptor *config,
                          struct usb_interface_descriptor *interface ) {
        struct ecm_ethernet_descriptor *desc;

        for_each_interface_descriptor ( desc, config, interface ) {
                if ( ( desc->header.type == USB_CS_INTERFACE_DESCRIPTOR ) &&
                     ( desc->subtype == CDC_SUBTYPE_ETHERNET ) )
                        return desc;
        }
        return NULL;
}

/**
 * Get hardware MAC address
 *
 * @v func              USB function
 * @v desc              Ethernet functional descriptor
 * @v netdev            Network device
 * @ret rc              Return status code
 */
int ecm_fetch_mac ( struct usb_function *func,
                    struct ecm_ethernet_descriptor *desc,
                    struct net_device *netdev ) {
        struct usb_device *usb = func->usb;
        char buf[ base16_encoded_len ( ETH_ALEN ) + 1 /* NUL */ ];
        uint8_t amac[ETH_ALEN];
        int len;
        int rc;

        /* Fetch MAC address string */
        buf[ sizeof ( buf ) - 1 ] = '\0';
        len = usb_get_string_descriptor ( usb, desc->mac, 0, buf,
                                          ( sizeof ( buf ) - 1 ) );
        if ( len < 0 ) {
                rc = len;
                return rc;
        }

        /* Sanity check */
        if ( len != ( ( int ) ( sizeof ( buf ) - 1 /* NUL */ ) ) ) {
                DBGC ( usb, "USB %s has invalid ECM MAC \"%s\"\n",
                       func->name, buf );
                return -EINVAL;
        }

        /* Decode MAC address */
        len = base16_decode ( buf, netdev->hw_addr, ETH_ALEN );
        if ( len < 0 ) {
                rc = len;
                DBGC ( usb, "USB %s could not decode ECM MAC \"%s\": %s\n",
                       func->name, buf, strerror ( rc ) );
                return rc;
        }

        /* Apply system-specific MAC address as current link-layer
         * address, if present.
         */
        if ( ( rc = acpi_mac ( amac ) ) == 0 ) {
                memcpy ( netdev->ll_addr, amac, ETH_ALEN );
                DBGC ( usb, "USB %s using system-specific MAC %s\n",
                       func->name, eth_ntoa ( netdev->ll_addr ) );
        }

        return 0;
}

/******************************************************************************
 *
 * CDC-ECM communications interface
 *
 ******************************************************************************
 */

/**
 * Complete interrupt transfer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void ecm_intr_complete ( struct usb_endpoint *ep,
                                struct io_buffer *iobuf, int rc ) {
        struct ecm_device *ecm = container_of ( ep, struct ecm_device,
                                                usbnet.intr );
        struct net_device *netdev = ecm->netdev;
        struct usb_setup_packet *message;
        size_t len = iob_len ( iobuf );

        /* Profile completions */
        profile_start ( &ecm_intr_profiler );

        /* Ignore packets cancelled when the endpoint closes */
        if ( ! ep->open )
                goto ignore;

        /* Drop packets with errors */
        if ( rc != 0 ) {
                DBGC ( ecm, "ECM %p interrupt failed: %s\n",
                       ecm, strerror ( rc ) );
                DBGC_HDA ( ecm, 0, iobuf->data, iob_len ( iobuf ) );
                goto error;
        }

        /* Extract message header */
        if ( len < sizeof ( *message ) ) {
                DBGC ( ecm, "ECM %p underlength interrupt:\n", ecm );
                DBGC_HDA ( ecm, 0, iobuf->data, iob_len ( iobuf ) );
                rc = -EINVAL;
                goto error;
        }
        message = iobuf->data;

        /* Parse message header */
        switch ( message->request ) {

        case cpu_to_le16 ( CDC_NETWORK_CONNECTION ) :
                if ( message->value && ! netdev_link_ok ( netdev ) ) {
                        DBGC ( ecm, "ECM %p link up\n", ecm );
                        netdev_link_up ( netdev );
                } else if ( netdev_link_ok ( netdev ) && ! message->value ) {
                        DBGC ( ecm, "ECM %p link down\n", ecm );
                        netdev_link_down ( netdev );
                }
                break;

        case cpu_to_le16 ( CDC_CONNECTION_SPEED_CHANGE ) :
                /* Ignore */
                break;

        default:
                DBGC ( ecm, "ECM %p unrecognised interrupt:\n", ecm );
                DBGC_HDA ( ecm, 0, iobuf->data, iob_len ( iobuf ) );
                rc = -ENOTSUP;
                goto error;
        }

        /* Free I/O buffer */
        free_iob ( iobuf );
        profile_stop ( &ecm_intr_profiler );

        return;

 error:
        netdev_rx_err ( netdev, iob_disown ( iobuf ), rc );
 ignore:
        free_iob ( iobuf );
        return;
}

/** Interrupt endpoint operations */
static struct usb_endpoint_driver_operations ecm_intr_operations = {
        .complete = ecm_intr_complete,
};

/******************************************************************************
 *
 * CDC-ECM data interface
 *
 ******************************************************************************
 */

/**
 * Complete bulk IN transfer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void ecm_in_complete ( struct usb_endpoint *ep, struct io_buffer *iobuf,
                              int rc ) {
        struct ecm_device *ecm = container_of ( ep, struct ecm_device,
                                                usbnet.in );
        struct net_device *netdev = ecm->netdev;

        /* Profile receive completions */
        profile_start ( &ecm_in_profiler );

        /* Ignore packets cancelled when the endpoint closes */
        if ( ! ep->open )
                goto ignore;

        /* Record USB errors against the network device */
        if ( rc != 0 ) {
                DBGC ( ecm, "ECM %p bulk IN failed: %s\n",
                       ecm, strerror ( rc ) );
                goto error;
        }

        /* Hand off to network stack */
        netdev_rx ( netdev, iob_disown ( iobuf ) );

        profile_stop ( &ecm_in_profiler );
        return;

 error:
        netdev_rx_err ( netdev, iob_disown ( iobuf ), rc );
 ignore:
        free_iob ( iobuf );
}

/** Bulk IN endpoint operations */
static struct usb_endpoint_driver_operations ecm_in_operations = {
        .complete = ecm_in_complete,
};

/**
 * Transmit packet
 *
 * @v ecm               CDC-ECM device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int ecm_out_transmit ( struct ecm_device *ecm,
                              struct io_buffer *iobuf ) {
        int rc;

        /* Profile transmissions */
        profile_start ( &ecm_out_profiler );

        /* Enqueue I/O buffer */
        if ( ( rc = usb_stream ( &ecm->usbnet.out, iobuf, 1 ) ) != 0 )
                return rc;

        profile_stop ( &ecm_out_profiler );
        return 0;
}

/**
 * Complete bulk OUT transfer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void ecm_out_complete ( struct usb_endpoint *ep, struct io_buffer *iobuf,
                               int rc ) {
        struct ecm_device *ecm = container_of ( ep, struct ecm_device,
                                                usbnet.out );
        struct net_device *netdev = ecm->netdev;

        /* Report TX completion */
        netdev_tx_complete_err ( netdev, iobuf, rc );
}

/** Bulk OUT endpoint operations */
static struct usb_endpoint_driver_operations ecm_out_operations = {
        .complete = ecm_out_complete,
};

/******************************************************************************
 *
 * Network device interface
 *
 ******************************************************************************
 */

/**
 * Open network device
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int ecm_open ( struct net_device *netdev ) {
        struct ecm_device *ecm = netdev->priv;
        struct usb_device *usb = ecm->usb;
        unsigned int filter;
        int rc;

        /* Open USB network device */
        if ( ( rc = usbnet_open ( &ecm->usbnet ) ) != 0 ) {
                DBGC ( ecm, "ECM %p could not open: %s\n",
                       ecm, strerror ( rc ) );
                goto err_open;
        }

        /* Set packet filter */
        filter = ( ECM_PACKET_TYPE_PROMISCUOUS |
                   ECM_PACKET_TYPE_ALL_MULTICAST |
                   ECM_PACKET_TYPE_DIRECTED |
                   ECM_PACKET_TYPE_BROADCAST );
        if ( ( rc = usb_control ( usb, ECM_SET_ETHERNET_PACKET_FILTER,
                                  filter, ecm->usbnet.comms, NULL, 0 ) ) != 0 ){
                DBGC ( ecm, "ECM %p could not set packet filter: %s\n",
                       ecm, strerror ( rc ) );
                goto err_set_filter;
        }

        return 0;

 err_set_filter:
        usbnet_close ( &ecm->usbnet );
 err_open:
        return rc;
}

/**
 * Close network device
 *
 * @v netdev            Network device
 */
static void ecm_close ( struct net_device *netdev ) {
        struct ecm_device *ecm = netdev->priv;

        /* Close USB network device */
        usbnet_close ( &ecm->usbnet );
}

/**
 * Transmit packet
 *
 * @v netdev            Network device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int ecm_transmit ( struct net_device *netdev,
                          struct io_buffer *iobuf ) {
        struct ecm_device *ecm = netdev->priv;
        int rc;

        /* Transmit packet */
        if ( ( rc = ecm_out_transmit ( ecm, iobuf ) ) != 0 )
                return rc;

        return 0;
}

/**
 * Poll for completed and received packets
 *
 * @v netdev            Network device
 */
static void ecm_poll ( struct net_device *netdev ) {
        struct ecm_device *ecm = netdev->priv;
        int rc;

        /* Poll USB bus */
        usb_poll ( ecm->bus );

        /* Refill endpoints */
        if ( ( rc = usbnet_refill ( &ecm->usbnet ) ) != 0 )
                netdev_rx_err ( netdev, NULL, rc );
}

/** CDC-ECM network device operations */
static struct net_device_operations ecm_operations = {
        .open           = ecm_open,
        .close          = ecm_close,
        .transmit       = ecm_transmit,
        .poll           = ecm_poll,
};

/******************************************************************************
 *
 * USB interface
 *
 ******************************************************************************
 */

/**
 * Probe device
 *
 * @v func              USB function
 * @v config            Configuration descriptor
 * @ret rc              Return status code
 */
static int ecm_probe ( struct usb_function *func,
                       struct usb_configuration_descriptor *config ) {
        struct usb_device *usb = func->usb;
        struct net_device *netdev;
        struct ecm_device *ecm;
        struct usb_interface_descriptor *comms;
        struct ecm_ethernet_descriptor *ethernet;
        int rc;

        /* Allocate and initialise structure */
        netdev = alloc_etherdev ( sizeof ( *ecm ) );
        if ( ! netdev ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        netdev_init ( netdev, &ecm_operations );
        netdev->dev = &func->dev;
        ecm = netdev->priv;
        memset ( ecm, 0, sizeof ( *ecm ) );
        ecm->usb = usb;
        ecm->bus = usb->port->hub->bus;
        ecm->netdev = netdev;
        usbnet_init ( &ecm->usbnet, func, &ecm_intr_operations,
                      &ecm_in_operations, &ecm_out_operations );
        usb_refill_init ( &ecm->usbnet.intr, 0, 0, ECM_INTR_MAX_FILL );
        usb_refill_init ( &ecm->usbnet.in, 0, ECM_IN_MTU, ECM_IN_MAX_FILL );
        DBGC ( ecm, "ECM %p on %s\n", ecm, func->name );

        /* Describe USB network device */
        if ( ( rc = usbnet_describe ( &ecm->usbnet, config ) ) != 0 ) {
                DBGC ( ecm, "ECM %p could not describe: %s\n",
                       ecm, strerror ( rc ) );
                goto err_describe;
        }

        /* Locate Ethernet descriptor */
        comms = usb_interface_descriptor ( config, ecm->usbnet.comms, 0 );
        assert ( comms != NULL );
        ethernet = ecm_ethernet_descriptor ( config, comms );
        if ( ! ethernet ) {
                DBGC ( ecm, "ECM %p has no Ethernet descriptor\n", ecm );
                rc = -EINVAL;
                goto err_ethernet;
        }

        /* Fetch MAC address */
        if ( ( rc = ecm_fetch_mac ( func, ethernet, netdev ) ) != 0 ) {
                DBGC ( ecm, "ECM %p could not fetch MAC address: %s\n",
                       ecm, strerror ( rc ) );
                goto err_fetch_mac;
        }

        /* Register network device */
        if ( ( rc = register_netdev ( netdev ) ) != 0 )
                goto err_register;

        usb_func_set_drvdata ( func, ecm );
        return 0;

        unregister_netdev ( netdev );
 err_register:
 err_fetch_mac:
 err_ethernet:
 err_describe:
        netdev_nullify ( netdev );
        netdev_put ( netdev );
 err_alloc:
        return rc;
}

/**
 * Remove device
 *
 * @v func              USB function
 */
static void ecm_remove ( struct usb_function *func ) {
        struct ecm_device *ecm = usb_func_get_drvdata ( func );
        struct net_device *netdev = ecm->netdev;

        unregister_netdev ( netdev );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
}

/** CDC-ECM device IDs */
static struct usb_device_id ecm_ids[] = {
        {
                .name = "cdc-ecm",
                .vendor = USB_ANY_ID,
                .product = USB_ANY_ID,
        },
};

/** CDC-ECM driver */
struct usb_driver ecm_driver __usb_driver = {
        .ids = ecm_ids,
        .id_count = ( sizeof ( ecm_ids ) / sizeof ( ecm_ids[0] ) ),
        .class = USB_CLASS_ID ( USB_CLASS_CDC, USB_SUBCLASS_CDC_ECM, 0 ),
        .score = USB_SCORE_NORMAL,
        .probe = ecm_probe,
        .remove = ecm_remove,
};