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

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

FILE_LICENCE ( GPL2_OR_LATER );

/*
 * isa.c implements a "classical" port-scanning method of ISA device
 * detection.  The driver must provide a list of probe addresses
 * (probe_addrs), together with a function (probe_addr) that can be
 * used to test for the physical presence of a device at any given
 * address.
 *
 * Note that this should probably be considered the "last resort" for
 * device probing.  If the card supports ISAPnP or EISA, use that
 * instead.  Some cards (e.g. the 3c509) implement a proprietary
 * ISAPnP-like mechanism.
 *
 * The ISA probe address list can be overridden by config.h; if the
 * user specifies ISA_PROBE_ADDRS then that list will be used first.
 * (If ISA_PROBE_ONLY is defined, the driver's own list will never be
 * used).
 */

/*
 * User-supplied probe address list
 *
 */
static isa_probe_addr_t isa_extra_probe_addrs[] = {
#ifdef ISA_PROBE_ADDRS
        ISA_PROBE_ADDRS
#endif
};
#define ISA_EXTRA_PROBE_ADDR_COUNT \
     ( sizeof ( isa_extra_probe_addrs ) / sizeof ( isa_extra_probe_addrs[0] ) )

#define ISA_IOIDX_MIN( driver ) ( -ISA_EXTRA_PROBE_ADDR_COUNT )
#ifdef ISA_PROBE_ONLY
#define ISA_IOIDX_MAX( driver ) ( -1 )
#else
#define ISA_IOIDX_MAX( driver ) ( (int) (driver)->addr_count - 1 )
#endif

#define ISA_IOADDR( driver, ioidx )                                       \
        ( ( (ioidx) < 0 ) ?                                               \
          isa_extra_probe_addrs[ (ioidx) + ISA_EXTRA_PROBE_ADDR_COUNT ] : \
          (driver)->probe_addrs[(ioidx)] )

static void isabus_remove ( struct root_device *rootdev );

/**
 * Probe an ISA device
 *
 * @v isa               ISA device
 * @ret rc              Return status code
 */
static int isa_probe ( struct isa_device *isa ) {
        int rc;

        DBG ( "Trying ISA driver %s at I/O %04x\n",
              isa->driver->name, isa->ioaddr );

        if ( ( rc = isa->driver->probe ( isa ) ) != 0 ) {
                DBG ( "...probe failed\n" );
                return rc;
        }

        DBG ( "...device found\n" );
        return 0;
}

/**
 * Remove an ISA device
 *
 * @v isa               ISA device
 */
static void isa_remove ( struct isa_device *isa ) {
        isa->driver->remove ( isa );
        DBG ( "Removed ISA%04x\n", isa->ioaddr );
}

/**
 * Probe ISA root bus
 *
 * @v rootdev           ISA bus root device
 *
 * Scans the ISA bus for devices and registers all devices it can
 * find.
 */
static int isabus_probe ( struct root_device *rootdev ) {
        struct isa_device *isa = NULL;
        struct isa_driver *driver;
        int ioidx;
        int rc;

        for_each_table_entry ( driver, ISA_DRIVERS ) {
                for ( ioidx = ISA_IOIDX_MIN ( driver ) ;
                      ioidx <= ISA_IOIDX_MAX ( driver ) ; ioidx++ ) {
                        /* Allocate struct isa_device */
                        if ( ! isa )
                                isa = malloc ( sizeof ( *isa ) );
                        if ( ! isa ) {
                                rc = -ENOMEM;
                                goto err;
                        }
                        memset ( isa, 0, sizeof ( *isa ) );
                        isa->driver = driver;
                        isa->ioaddr = ISA_IOADDR ( driver, ioidx );

                        /* Add to device hierarchy */
                        snprintf ( isa->dev.name, sizeof ( isa->dev.name ),
                                   "ISA%04x", isa->ioaddr );
                        isa->dev.desc.bus_type = BUS_TYPE_ISA;
                        isa->dev.desc.vendor = driver->vendor_id;
                        isa->dev.desc.device = driver->prod_id;
                        isa->dev.parent = &rootdev->dev;
                        list_add ( &isa->dev.siblings,
                                   &rootdev->dev.children );
                        INIT_LIST_HEAD ( &isa->dev.children );

                        /* Try probing at this I/O address */
                        if ( isa_probe ( isa ) == 0 ) {
                                /* isadev registered, we can drop our ref */
                                isa = NULL;
                        } else {
                                /* Not registered; re-use struct */
                                list_del ( &isa->dev.siblings );
                        }
                }
        }

        free ( isa );
        return 0;

 err:
        free ( isa );
        isabus_remove ( rootdev );
        return rc;
}

/**
 * Remove ISA root bus
 *
 * @v rootdev           ISA bus root device
 */
static void isabus_remove ( struct root_device *rootdev ) {
        struct isa_device *isa;
        struct isa_device *tmp;

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

/** ISA bus root device driver */
static struct root_driver isa_root_driver = {
        .probe = isabus_probe,
        .remove = isabus_remove,
};

/** ISA bus root device */
struct root_device isa_root_device __root_device = {
        .dev = { .name = "ISA" },
        .driver = &isa_root_driver,
};