source: bootcd/isolinux/syslinux-6.03/gpxe/src/drivers/bus/mca.c

/*
 * MCA bus driver code
 *
 * Abstracted from 3c509.c.
 *
 */

FILE_LICENCE ( BSD2 );

#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <gpxe/io.h>
#include <gpxe/mca.h>

static void mcabus_remove ( struct root_device *rootdev );

/**
 * Probe an MCA device
 *
 * @v mca               MCA device
 * @ret rc              Return status code
 *
 * Searches for a driver for the MCA device.  If a driver is found,
 * its probe() routine is called.
 */
static int mca_probe ( struct mca_device *mca ) {
        struct mca_driver *driver;
        struct mca_device_id *id;
        unsigned int i;
        int rc;

        DBG ( "Adding MCA slot %02x (ID %04x POS "
              "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x)\n",
              mca->slot, MCA_ID ( mca ),
              mca->pos[0], mca->pos[1], mca->pos[2], mca->pos[3],
              mca->pos[4], mca->pos[5], mca->pos[6], mca->pos[7] );

        for_each_table_entry ( driver, MCA_DRIVERS ) {
                for ( i = 0 ; i < driver->id_count ; i++ ) {
                        id = &driver->ids[i];
                        if ( id->id != MCA_ID ( mca ) )
                                continue;
                        mca->driver = driver;
                        mca->driver_name = id->name;
                        DBG ( "...using driver %s\n", mca->driver_name );
                        if ( ( rc = driver->probe ( mca, id ) ) != 0 ) {
                                DBG ( "......probe failed\n" );
                                continue;
                        }
                        return 0;
                }
        }

        DBG ( "...no driver found\n" );
        return -ENOTTY;
}

/**
 * Remove an MCA device
 *
 * @v mca               MCA device
 */
static void mca_remove ( struct mca_device *mca ) {
        mca->driver->remove ( mca );
        DBG ( "Removed MCA device %02x\n", mca->slot );
}

/**
 * Probe MCA root bus
 *
 * @v rootdev           MCA bus root device
 *
 * Scans the MCA bus for devices and registers all devices it can
 * find.
 */
static int mcabus_probe ( struct root_device *rootdev ) {
        struct mca_device *mca = NULL;
        unsigned int slot;
        int seen_non_ff;
        unsigned int i;
        int rc;

        for ( slot = 0 ; slot <= MCA_MAX_SLOT_NR ; slot++ ) {
                /* Allocate struct mca_device */
                if ( ! mca )
                        mca = malloc ( sizeof ( *mca ) );
                if ( ! mca ) {
                        rc = -ENOMEM;
                        goto err;
                }
                memset ( mca, 0, sizeof ( *mca ) );
                mca->slot = slot;

                /* Make sure motherboard setup is off */
                outb_p ( 0xff, MCA_MOTHERBOARD_SETUP_REG );

                /* Select the slot */
                outb_p ( 0x8 | ( mca->slot & 0xf ), MCA_ADAPTER_SETUP_REG );

                /* Read the POS registers */
                seen_non_ff = 0;
                for ( i = 0 ; i < ( sizeof ( mca->pos ) /
                                    sizeof ( mca->pos[0] ) ) ; i++ ) {
                        mca->pos[i] = inb_p ( MCA_POS_REG ( i ) );
                        if ( mca->pos[i] != 0xff )
                                seen_non_ff = 1;
                }
        
                /* Kill all setup modes */
                outb_p ( 0, MCA_ADAPTER_SETUP_REG );

                /* If all POS registers are 0xff, this means there's no device
                 * present
                 */
                if ( ! seen_non_ff )
                        continue;

                /* Add to device hierarchy */
                snprintf ( mca->dev.name, sizeof ( mca->dev.name ),
                           "MCA%02x", slot );
                mca->dev.desc.bus_type = BUS_TYPE_MCA;
                mca->dev.desc.vendor = GENERIC_MCA_VENDOR;
                mca->dev.desc.device = MCA_ID ( mca );
                mca->dev.parent = &rootdev->dev;
                list_add ( &mca->dev.siblings, &rootdev->dev.children );
                INIT_LIST_HEAD ( &mca->dev.children );

                /* Look for a driver */
                if ( mca_probe ( mca ) == 0 ) {
                        /* mcadev registered, we can drop our ref */
                        mca = NULL;
                } else {
                        /* Not registered; re-use struct */
                        list_del ( &mca->dev.siblings );
                }
        }

        free ( mca );
        return 0;

 err:
        free ( mca );
        mcabus_remove ( rootdev );
        return rc;
}

/**
 * Remove MCA root bus
 *
 * @v rootdev           MCA bus root device
 */
static void mcabus_remove ( struct root_device *rootdev ) {
        struct mca_device *mca;
        struct mca_device *tmp;

        list_for_each_entry_safe ( mca, tmp, &rootdev->dev.children,
                                   dev.siblings ) {
                mca_remove ( mca );
                list_del ( &mca->dev.siblings );
                free ( mca );
        }
}

/** MCA bus root device driver */
static struct root_driver mca_root_driver = {
        .probe = mcabus_probe,
        .remove = mcabus_remove,
};

/** MCA bus root device */
struct root_device mca_root_device __root_device = {
        .dev = { .name = "MCA" },
        .driver = &mca_root_driver,
};