mii.c

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/*
 * Copyright (C) 2012 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 <unistd.h>
#include <errno.h>
#include <ipxe/mii.h>

/** @file
 *
 * Media Independent Interface
 *
 */

/**
 * Restart autonegotiation
 *
 * @v mii               MII device
 * @ret rc              Return status code
 */
int mii_restart ( struct mii_device *mii ) {
        int bmcr;
        int rc;

        /* Read BMCR */
        bmcr = mii_read ( mii, MII_BMCR );
        if ( bmcr < 0 ) {
                rc = bmcr;
                DBGC ( mii, "MII %p could not read BMCR: %s\n",
                       mii, strerror ( rc ) );
                return rc;
        }

        /* Enable and restart autonegotiation */
        bmcr |= ( BMCR_ANENABLE | BMCR_ANRESTART );
        if ( ( rc = mii_write ( mii, MII_BMCR, bmcr ) ) != 0 ) {
                DBGC ( mii, "MII %p could not write BMCR: %s\n",
                       mii, strerror ( rc ) );
                return rc;
        }

        DBGC ( mii, "MII %p restarted autonegotiation\n", mii );
        return 0;
}

/**
 * Reset MII device
 *
 * @v mii               MII device
 * @ret rc              Return status code
 */
int mii_reset ( struct mii_device *mii ) {
        unsigned int i;
        int bmcr;
        int rc;

        /* Power-up, enable autonegotiation and initiate reset */
        if ( ( rc = mii_write ( mii, MII_BMCR,
                                ( BMCR_RESET | BMCR_ANENABLE ) ) ) != 0 ) {
                DBGC ( mii, "MII %p could not write BMCR: %s\n",
                       mii, strerror ( rc ) );
                return rc;
        }

        /* Wait for reset to complete */
        for ( i = 0 ; i < MII_RESET_MAX_WAIT_MS ; i++ ) {

                /* Check if reset has completed */
                bmcr = mii_read ( mii, MII_BMCR );
                if ( bmcr < 0 ) {
                        rc = bmcr;
                        DBGC ( mii, "MII %p could not read BMCR: %s\n",
                               mii, strerror ( rc ) );
                        return rc;
                }

                /* If reset is not complete, delay 1ms and retry */
                if ( bmcr & BMCR_RESET ) {
                        mdelay ( 1 );
                        continue;
                }

                /* Force autonegotation on again, in case it was
                 * cleared by the reset.
                 */
                if ( ( rc = mii_restart ( mii ) ) != 0 )
                        return rc;

                DBGC ( mii, "MII %p reset after %dms\n", mii, i );
                return 0;
        }

        DBGC ( mii, "MII %p timed out waiting for reset\n", mii );
        return -ETIMEDOUT;
}

/**
 * Update link status via MII
 *
 * @v mii               MII device
 * @v netdev            Network device
 * @ret rc              Return status code
 */
int mii_check_link ( struct mii_device *mii, struct net_device *netdev ) {
        int bmsr;
        int link;
        int rc;

        /* Read BMSR */
        bmsr = mii_read ( mii, MII_BMSR );
        if ( bmsr < 0 ) {
                rc = bmsr;
                return rc;
        }

        /* Report link status */
        link = ( bmsr & BMSR_LSTATUS );
        DBGC ( mii, "MII %p link %s (BMSR %#04x)\n",
               mii, ( link ? "up" : "down" ), bmsr );
        if ( link ) {
                netdev_link_up ( netdev );
        } else {
                netdev_link_down ( netdev );
        }

        return 0;
}

/**
 * Find PHY address
 *
 * @v mii               MII device
 * @ret rc              Return status code
 */
int mii_find ( struct mii_device *mii ) {
        unsigned int address;
        int id;

        /* Try all possible PHY addresses */
        for ( address = 0 ; address <= MII_MAX_PHY_ADDRESS ; address++ ) {
                mii->address = address;
                id = mii_read ( mii, MII_PHYSID1 );
                if ( ( id > 0x0000 ) && ( id < 0xffff ) ) {
                        DBGC ( mii, "MII %p found PHY at address %d\n",
                               mii, address );
                        return 0;
                }
        }

        DBGC ( mii, "MII %p failed to find an address\n", mii );
        return -ENOENT;
}