[unix-history] / usr / src / sys / i386 / i386 / autoconf.c

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* %sccs.include.386.c%
*
*      @(#)autoconf.c  5.6 (Berkeley) %G%
*/

/*
* Setup the system to run on the current machine.
*
* Configure() is called at boot time and initializes the vba 
* device tables and the memory controller monitoring.  Available
* devices are determined (from possibilities mentioned in ioconf.c),
* and the drivers are initialized.
*/
#include "param.h"
#include "systm.h"
#include "map.h"
#include "buf.h"
#include "dkstat.h"
#include "vm.h"
#include "conf.h"
#include "dmap.h"
#include "reboot.h"

#include "machine/pte.h"

/*
* The following several variables are related to
* the configuration process, and are used in initializing
* the machine.
*/
int     dkn;            /* number of iostat dk numbers assigned so far */
extern int      cold;           /* cold start flag initialized in locore.s */

/*
* Determine i/o configuration for a machine.
*/
configure()
{

#include "isa.h"
#if NISA > 0
       isa_configure();
#endif

#if GENERICxxx
       if ((boothowto & RB_ASKNAME) == 0)
               setroot();
       setconf();
#else
       setroot();
#endif
       /*
        * Configure swap area and related system
        * parameter based on device(s) used.
        */
       swapconf();
       cold = 0;
}

/*
* Configure swap space and related parameters.
*/
swapconf()
{
       register struct swdevt *swp;
       register int nblks;

       for (swp = swdevt; swp->sw_dev > 0; swp++)
       {
               if ( swp->sw_dev < 0 || swp->sw_dev > nblkdev ) break;
               if (bdevsw[major(swp->sw_dev)].d_psize) {
                       nblks =
                         (*bdevsw[major(swp->sw_dev)].d_psize)(swp->sw_dev);
                       if (nblks != -1 &&
                           (swp->sw_nblks == 0 || swp->sw_nblks > nblks))
                               swp->sw_nblks = nblks;
               }
       }
       if (dumplo == 0 && bdevsw[major(dumpdev)].d_psize)
               dumplo = (*bdevsw[major(dumpdev)].d_psize)(dumpdev) - physmem;
       if (dumplo < 0)
               dumplo = 0;
}

#define DOSWAP                  /* change swdevt, argdev, and dumpdev too */
u_long  bootdev = 0;            /* should be dev_t, but not until 32 bits */

static  char devname[][2] = {
       'w','d',        /* 0 = wd */
       's','w',        /* 1 = sw */
       'f','d',        /* 2 = fd */
       'w','t',        /* 3 = wt */
       'x','d',        /* 4 = xd */
};

#define PARTITIONMASK   0x7
#define PARTITIONSHIFT  3

/*
* Attempt to find the device from which we were booted.
* If we can do so, and not instructed not to do so,
* change rootdev to correspond to the load device.
*/
setroot()
{
       int  majdev, mindev, unit, part, adaptor;
       dev_t temp, orootdev;
       struct swdevt *swp;

       if (boothowto & RB_DFLTROOT ||
           (bootdev & B_MAGICMASK) != (u_long)B_DEVMAGIC)
               return;
       majdev = (bootdev >> B_TYPESHIFT) & B_TYPEMASK;
       if (majdev > sizeof(devname) / sizeof(devname[0]))
               return;
       adaptor = (bootdev >> B_ADAPTORSHIFT) & B_ADAPTORMASK;
       part = (bootdev >> B_PARTITIONSHIFT) & B_PARTITIONMASK;
       unit = (bootdev >> B_UNITSHIFT) & B_UNITMASK;
       mindev = (unit << PARTITIONSHIFT) + part;
       orootdev = rootdev;
       rootdev = makedev(majdev, mindev);
       /*
        * If the original rootdev is the same as the one
        * just calculated, don't need to adjust the swap configuration.
        */
       if (rootdev == orootdev)
               return;
       printf("changing root device to %c%c%d%c\n",
               devname[majdev][0], devname[majdev][1],
               mindev >> PARTITIONSHIFT, part + 'a');
#ifdef DOSWAP
       mindev &= ~PARTITIONMASK;
       for (swp = swdevt; swp->sw_dev; swp++) {
               if (majdev == major(swp->sw_dev) &&
                   mindev == (minor(swp->sw_dev) & ~PARTITIONMASK)) {
                       temp = swdevt[0].sw_dev;
                       swdevt[0].sw_dev = swp->sw_dev;
                       swp->sw_dev = temp;
                       break;
               }
       }
       if (swp->sw_dev == 0)
               return;
       /*
        * If argdev and dumpdev were the same as the old primary swap
        * device, move them to the new primary swap device.
        */
       if (temp == dumpdev)
               dumpdev = swdevt[0].sw_dev;
       if (temp == argdev)
               argdev = swdevt[0].sw_dev;
#endif
}