[apple/xnu.git] / osfmk / ppc / pms.c

/*
 * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
#include <ppc/machine_routines.h>
#include <ppc/machine_cpu.h>
#include <ppc/exception.h>
#include <ppc/misc_protos.h>
#include <ppc/Firmware.h>
#include <ppc/pmap.h>
#include <ppc/proc_reg.h>
#include <ppc/pms.h>
#include <ppc/savearea.h>
#include <ppc/exception.h>
#include <kern/processor.h>

extern int real_ncpus;

static uint32_t pmsSyncrolator = 0;                                     /* Only one control operation at a time please */
uint32_t pmsBroadcastWait = 0;                                          /* Number of outstanding broadcasts */

int pmsInstalled = 0;                                                           /* Power Management Stepper can run and has table installed */
int pmsExperimental = 0;                                                        /* Power Management Stepper in experimental mode */
decl_simple_lock_data(,pmsBuildLock)                            /* Make sure only one guy can replace table  at the same time */

static pmsDef *altDpmsTab = 0;                                          /* Alternate step definition table */
static uint32_t altDpmsTabSize = 0;                                     /* Size of alternate step definition table */

pmsDef pmsDummy = {                                                                     /* This is the dummy step for initialization.  All it does is to park */
        .pmsLimit = 0,                                                                  /* Time doesn't matter for a park */
        .pmsStepID = pmsMaxStates - 1,                                  /* Use the very last ID number for the dummy */
        .pmsSetCmd = pmsParkIt,                                                 /* Force us to be parked */
        .sf.pmsSetFuncInd = 0,                                                  /* No platform call for this one */
        .pmsDown = pmsPrepSleep,                                                /* We always park */
        .pmsNext = pmsPrepSleep                                                 /* We always park */
};

pmsStat pmsStatsd[4][pmsMaxStates];                                     /* Generate enough statistics blocks for 4 processors */

pmsCtl pmsCtls = {                                                                      /* Power Management Stepper control */
        .pmsStats = &pmsStatsd
};

pmsSetFunc_t pmsFuncTab[pmsSetFuncMax] = {0};           /* This is the function index table */
pmsQueryFunc_t pmsQueryFunc = 0;                                        /* Pointer to pmsQuery function */
uint32_t pmsPlatformData = 0;                                           /* Data provided by and passed to platform functions */


/*
 *      Do any initialization needed
 */
 
void pmsInit(void) {

        int i;
        
        simple_lock_init(&pmsBuildLock, 0);                             /* Initialize the build lock */
        for(i = 0; i < pmsMaxStates; i++) pmsCtls.pmsDefs[i] = &pmsDummy;       /* Initialize the table to dummy steps */

        return;
}


/*
 *      Start the power management stepper on all processors
 *
 *      All processors must be parked.  This should be called when the hardware
 *      is ready to step.  Probably only at boot and after wake from sleep.
 *
 */
 
 void pmsStart(void) {

        boolean_t       intr;

        if(!pmsInstalled) return;                                               /* We can't do this if no table installed */

        intr = ml_set_interrupts_enabled(FALSE);                /* No interruptions in here */
        pmsRun(pmsStartUp);                                                             /* Start running the stepper everywhere */
        (void)ml_set_interrupts_enabled(intr);                  /* Restore interruptions */

        return;
 
 }
 

/*
 *      Park the stepper execution.  This will force the stepper on this
 *      processor to abandon its current step and stop.  No changes to the
 *      hardware state is made and any previous step is lost.
 *      
 *      This is used as the initial state at startup and when the step table
 *      is being changed.
 *
 */
 
void pmsPark(void) {

        boolean_t       intr;

        if(!pmsInstalled) return;                                               /* We can't do this if no table installed */

        intr = ml_set_interrupts_enabled(FALSE);                /* No interruptions in here */
        pmsSetStep(pmsParked, 0);                                               /* Park the stepper */
        (void)ml_set_interrupts_enabled(intr);                  /* Restore interruptions */
        
        return;

}
 

/*
 *      Steps down to a lower power.
 *      Interrupts must be off...
 */

void pmsDown(void) {

        struct per_proc_info *pp;
        uint32_t nstate;
        
        pp = getPerProc();                                                              /* Get our per_proc */
        
        if(!pmsInstalled || pp->pms.pmsState == pmsParked) return;              /* No stepping if parked or not installed */
        
        nstate = pmsCtls.pmsDefs[pp->pms.pmsState]->pmsDown;    /* Get the downward step */
        pmsSetStep(nstate, 0);                                                  /* Step to it */
        return;
}


/*
 *      Steps up to a higher power.  The "timer" parameter is true if the
 *      step was driven due to the pms timer expiring.
 *
 *      Interrupts must be off...
 */
 
void pmsStep(int timer) {

        struct per_proc_info *pp;
        uint32_t nstate;
        int dir;
        
        pp = getPerProc();                                                              /* Get our per_proc */

        if(!pmsInstalled || pp->pms.pmsState == pmsParked) return;      /* No stepping if parked or not installed */
        
        nstate = pmsCtls.pmsDefs[pp->pms.pmsState]->pmsNext;    /* Assume a normal step */
        dir = 1;                                                                                /* A normal step is a step up */
        
        if(timer && (pmsCtls.pmsDefs[pp->pms.pmsState]->pmsSetCmd == pmsDelay)) {       /* If the timer expired and we are in a delay step, use the delay branch */
                nstate = pmsCtls.pmsDefs[pp->pms.pmsState]->pmsTDelay;  /* Get the delayed step */
                dir = 0;                                                                        /* Delayed steps are a step down for accounting purposes. */
        }

        pmsSetStep(nstate, dir);                                                /* Step to it  */
        return;
}


/*
 *      Set a specific step
 *
 *      We do not do statistics if exiting park
 *      Interrupts must be off...
 *
 */

void pmsSetStep(uint32_t nstep, int dir) {

        struct per_proc_info *pp;
        uint32_t pstate, ret, nCSetCmd, mCSetCmd;
        pmsDef *pnstate, *pcstate;
        uint64_t tb, nt, dur;
        int cpu, frompark;

        pp = getPerProc();                                                              /* Get our per_proc */
        cpu = cpu_number();                                                             /* Get our processor */
        
        while(1) {                                                                              /* Keep stepping until we get a delay */
                
                if(pp->pms.pmsCSetCmd & pmsMustCmp) {           /* Do we have to finish the delay before changing? */
                        while(mach_absolute_time() < pp->pms.pmsPop);   /* Yes, spin here... */
                }
                
                if((nstep == pmsParked) || ((uint32_t)pmsCtls.pmsDefs[nstep]->pmsSetCmd == pmsParkIt)) {        /* Are we parking? */
                        
                        tb = mach_absolute_time();                              /* What time is it? */
                        pp->pms.pmsStamp = tb;                                  /* Show transition now */
                        pp->pms.pmsPop = HalfwayToForever;              /* Set the pop way into the future */
                        pp->pms.pmsState = pmsParked;                   /* Make sure we are parked */
                        setTimerReq();                                                  /* Cancel our timer if going */
                        return;
                }

                pnstate = pmsCtls.pmsDefs[nstep];                       /* Point to the state definition */ 
                pstate = pp->pms.pmsState;                                      /* Save the current step */
                pp->pms.pmsState = nstep;                                       /* Set the current to the next step */

                if(pnstate->pmsSetCmd != pmsDelay) {            /* If this is not a delayed state, change the actual hardware now */
                        if(pnstate->pmsSetCmd & pmsCngCPU) pmsCPUSet(pnstate->pmsSetCmd);       /* We have some CPU work to do... */
                        if((uint32_t)pnstate->sf.pmsSetFunc) pnstate->sf.pmsSetFunc(pnstate->pmsSetCmd, cpu, pmsPlatformData);  /* Tell the platform to set power mode */
        
                        mCSetCmd = pnstate->pmsSetCmd & (pmsCngXClk | pmsCngCPU | pmsCngVolt);  /* Isolate just the change flags */
                        mCSetCmd = (mCSetCmd - (mCSetCmd >> 7)) | pmsSync | pmsMustCmp | pmsPowerID;    /* Form mask of bits that come from new command */
                        nCSetCmd = pp->pms.pmsCSetCmd & ~mCSetCmd;      /* Clear changing bits */
                        nCSetCmd = nCSetCmd | (pnstate->pmsSetCmd & mCSetCmd);  /* Flip on the changing bits and the always copy bits */
        
                        pp->pms.pmsCSetCmd = nCSetCmd;                  /* Set it for real */
                }
        
                tb = mach_absolute_time();                                      /* What time is it? */
                pp->pms.pmsPop = tb + pnstate->pmsLimit;        /* Set the next pop */
        
                if((pnstate->pmsSetCmd != pmsDelay) && (pp->pms.pmsCSetCmd & pmsSync) && (pnstate->pmsLimit != 0)) {    /* Is this a synchronous command with a delay? */
                        while(mach_absolute_time() < pp->pms.pmsPop);   /* Yes, spin here and wait it out... */
                }

/*
 *              Gather some statistics
 */
          
                dur = tb - pp->pms.pmsStamp;                            /* Get the amount of time we were in the old step */
                pp->pms.pmsStamp = tb;                                          /* Set the new timestamp */
                if(!(pstate == pmsParked)) {                            /* Only take stats if we were not parked */
                        pcstate = pmsCtls.pmsDefs[pstate];              /* Get the previous step */
                        pmsCtls.pmsStats[cpu][pcstate->pmsStepID].stTime[dir] += dur;   /* Accumulate the total time in the old step */ 
                        pmsCtls.pmsStats[cpu][pcstate->pmsStepID].stCnt[dir] += 1;      /* Count transitions */
                }

/*
 *              See if we are done chaining steps
 */
 
                if((pnstate->pmsSetCmd == pmsDelay) 
                        || (!(pp->pms.pmsCSetCmd & pmsSync) && (pnstate->pmsLimit != 0))) {     /* Is this not syncronous and a non-zero delay or a delayed step? */
                        setTimerReq();                                                  /* Start the timers ticking */
                        break;                                                                  /* We've stepped as far as we're going to... */
                }
                
                nstep = pnstate->pmsNext;                                       /* Chain on to the next */
        }

        return;

}

/*
 *      Either park the stepper or force the step on a parked stepper for local processor only
 *
 */
 
void pmsRunLocal(uint32_t nstep) {

        struct per_proc_info *pp;
        uint32_t cstate, ret, lastState;
        pmsDef *pnstate, *pcstate;
        uint64_t tb, nt, dur;
        int cpu, i, j;
        boolean_t       intr;

        if(!pmsInstalled) return;                                               /* Ignore this if no step programs installed... */

        intr = ml_set_interrupts_enabled(FALSE);                /* No interruptions in here */

        pp = getPerProc();                                                              /* Get our per_proc */

        if(nstep == pmsStartUp) {                                               /* Should we start up? */
                pmsCPUInit();                                                           /* Get us up to full with high voltage and park */
                nstep = pmsNormHigh;                                            /* Change request to transition to normal high */
        }

        lastState = pp->pms.pmsState;                                   /* Remember if we are parked now */

        pmsSetStep(nstep, 1);                                                   /* Step to the new state */
        
        if((lastState == pmsParked) && (pp->pms.pmsState != pmsParked)) {       /* Did we just unpark? */
                cpu = cpu_number();                                                     /* Get our processor */
                for(i = 0; i < pmsMaxStates; i++) {                     /* Step through the steps and clear the statistics since we were parked */
                        pmsCtls.pmsStats[cpu][i].stTime[0] = 0; /* Clear accumulated time - downward */ 
                        pmsCtls.pmsStats[cpu][i].stTime[1] = 0; /* Clear accumulated time - forward */  
                        pmsCtls.pmsStats[cpu][i].stCnt[0] = 0;  /* Clear transition count - downward */
                        pmsCtls.pmsStats[cpu][i].stCnt[1] = 0;  /* Clear transition count - forward */
                }
        }

        (void)ml_set_interrupts_enabled(intr);                  /* Restore interruptions */

        return;

}

/*
 *      Control the Power Management Stepper.
 *      Called from user state by the superuser via a ppc system call.
 *      Interruptions disabled.
 *
 */

int pmsCntrl(struct savearea *save) {

        uint32_t request, nstep, reqsize, result, presult;
        int ret, cpu;
        kern_return_t kret;
        pmsDef *ndefs;
        struct per_proc_info *pp;

        pp = getPerProc();                                                              /* Get our per_proc */
        cpu = cpu_number();                                                             /* Get our processor */
        
        if(!is_suser()) {                                                               /* We are better than most, */
                save->save_r3 = KERN_FAILURE;                           /* so we will only talk to the superuser. */
                return 1;                                                                       /* Turn up our noses, say "harrumph," and walk away... */
        }
        
        if(save->save_r3 >= pmsCFree) {                                 /* Can we understand the request? */
                save->save_r3 = KERN_INVALID_ARGUMENT;          /* What language are these guys talking in, anyway? */
                return 1;                                                                       /* Cock head like a confused puppy and run away... */
        }
        
        request = (int)save->save_r3;                                   /* Remember the request */
        reqsize = (uint32_t)save->save_r5;                              /* Get the size of the config table */

        if(request == pmsCQuery) {                                              /* Are we just checking? */
                result = pmsCPUquery() & pmsCPU;                        /* Get the processor data and make sure there is no slop */
                presult = 0;                                                            /* Assume nothing */
                if((uint32_t)pmsQueryFunc) presult = pmsQueryFunc(cpu, pmsPlatformData);        /* Go get the platform state */
                result = result | (presult & (pmsXClk | pmsVoltage | pmsPowerID));      /* Merge the platform state with no slop */
                save->save_r3 = result;                                         /* Tell 'em... */
                return 1;
        }
        
        if(request == pmsCExperimental) {                               /* Enter experimental mode? */
        
                if(pmsInstalled || (pmsExperimental & 1)) {     /* Are we already running or in experimental? */
                        save->save_r3 = KERN_FAILURE;                   /* Fail, since we are already running */
                        return 1;
                }
                
                pmsExperimental |= 1;                                           /* Flip us into experimental but don't change other flags */
                
                pmsCPUConf();                                                           /* Configure for this machine */
                pmsStart();                                                                     /* Start stepping */
                save->save_r3 = KERN_SUCCESS;                           /* We are victorious... */
                return 1;
        
        }

        if(request == pmsCCnfg) {                                               /* Do some up-front checking before we commit to doing this */
                if((reqsize > (pmsMaxStates * sizeof(pmsDef))) || (reqsize < (pmsFree * sizeof(pmsDef)))) {     /* Check that the size is reasonable */
                        save->save_r3 = KERN_NO_SPACE;                  /* Tell them that they messed up */
                        return 1;                                                               /* l8r... */
                }
        }


/*
 *      We are committed after here.  If there are any errors detected, we shouldn't die, but we
 *      will be stuck in park.
 *
 *      Also, we can possibly end up on another processor after the broadcast.
 *
 */
                
        if(!hw_compare_and_store(0, 1, &pmsSyncrolator)) {      /* Are we already doing this? */
                save->save_r3 = KERN_RESOURCE_SHORTAGE;         /* Tell them that we are already busy and to try again */
                return 1;                                                                       /* G'wan away and don't bother me... */
        }
        save->save_r3 = KERN_SUCCESS;                                   /* Assume success */

//      NOTE:  We will block in the following code until everyone has finished the prepare

        pmsRun(pmsPrepCng);                                                             /* Get everyone parked and in a proper state for step table changes, including me */
        
        if(request == pmsCPark) {                                               /* Is all we're supposed to do park? */
                pmsSyncrolator = 0;                                                     /* Free us up */
                return 1;                                                                       /* Well, then we're done... */
        }
        
        switch(request) {                                                               /* Select the routine */

                case pmsCStart:                                                         /* Starts normal steppping */
                        nstep = pmsNormHigh;                                    /* Set the request */
                        break;

                case pmsCFLow:                                                          /* Forces low power */
                        nstep = pmsLow;                                                 /* Set request */
                        break;

                case pmsCFHigh:                                                         /* Forces high power */
                        nstep = pmsHigh;                                                /* Set request */
                        break;

                case pmsCCnfg:                                                          /* Loads new stepper program */
                        
                        if(!(ndefs = (pmsDef *)kalloc(reqsize))) {      /* Get memory for the whole thing */
                                save->save_r3 = KERN_INVALID_ADDRESS;   /* Return invalid address */
                                pmsSyncrolator = 0;                                     /* Free us up */
                                return 1;                                                       /* All done... */
                        }
                        
                        ret = copyin((user_addr_t)((unsigned int)(save->save_r4)), (void *)ndefs, reqsize);     /* Get the new config table */
                        if(ret) {                                                               /* Hmmm, something went wrong with the copyin */
                                save->save_r3 = KERN_INVALID_ADDRESS;   /* Return invalid address */
                                kfree((vm_offset_t)ndefs, reqsize);     /* Free up the copied in data */
                                pmsSyncrolator = 0;                                     /* Free us up */
                                return 1;                                                       /* All done... */
                        }

                        kret = pmsBuild(ndefs, reqsize, 0, 0, 0);       /* Go build and replace the tables.  Make sure we keep the old platform stuff */
                        if(kret) {                                                              /* Hmmm, something went wrong with the compilation */
                                save->save_r3 = kret;                           /* Pass back the passed back return code */
                                kfree((vm_offset_t)ndefs, reqsize);     /* Free up the copied in data */
                                pmsSyncrolator = 0;                                     /* Free us up */
                                return 1;                                                       /* All done... */
                        }

                        nstep = pmsNormHigh;                                    /* Set the request */
                        break;

                default:
                        panic("pmsCntrl: stepper control is so very, very confused = %08X\n", request);
        
        }

        pmsRun(nstep);                                                                  /* Get everyone into step */
        pmsSyncrolator = 0;                                                             /* Free us up */
        return 1;                                                                               /* All done... */

}

/*
 *      Broadcast a change to all processors including ourselves.
 *      This must transition before broadcasting because we may block and end up on a different processor.
 *
 *      This will block until all processors have transitioned, so
 *      obviously, this can block.
 *
 *      Called with interruptions disabled.
 *
 */
 
void pmsRun(uint32_t nstep) {

        pmsRunLocal(nstep);                                                             /* If we aren't parking (we are already parked), transition ourselves */
        (void)cpu_broadcast(&pmsBroadcastWait, pmsRemote, nstep);       /* Tell everyone else to do it too */

        return;
        
}

/*
 *      Receive a broadcast and react.
 *      This is called from the interprocessor signal handler.
 *      We wake up the initiator after we are finished.
 *
 */
        
void pmsRemote(uint32_t nstep) {

        pmsRunLocal(nstep);                                                             /* Go set the step */
        if(!hw_atomic_sub(&pmsBroadcastWait, 1)) {              /* Drop the wait count */
                thread_wakeup((event_t)&pmsBroadcastWait);      /* If we were the last, wake up the signaller */
        }
        return;
}       


/*
 *      Build the tables needed for the stepper.  This includes both the step definitions and the step control table.
 *
 *      We most absolutely need to be parked before this happens because we're gonna change the table.
 *      We're going to have to be pretty complete about checking for errors.
 *      Also, a copy is always made because we don't want to be crippled by not being able to change
 *      the table or description formats.
 *
 *      We pass in a table of external functions and the new stepper def uses the corresponding 
 *      indexes rather than actual function addresses.  This is done so that a proper table can be
 *      built with the control syscall.  It can't supply addresses, so the index has to do.  We
 *      internalize the table so our caller does not need to keep it.  Note that passing in a 0
 *      will use the current function table.  Also note that entry 0 is reserved and must be 0,
 *      we will check and fail the build.
 *
 *      The platformData parameter is a 32-bit word of data that is passed unaltered to the set function.
 *
 *      The queryFunc parameter is the address of a function that will return the current state of the platform.
 *      The format of the data returned is the same as the platform specific portions of pmsSetCmd, i.e., pmsXClk,
 *      pmsVoltage, and any part of pmsPowerID that is maintained by the platform hardware (an example would be
 *      the values of the gpios that correspond to pmsPowerID).  The value should be constructed by querying
 *      hardware rather than returning a value cached by software. One of the intents of this function is to 
 *      help recover lost or determine initial power states.
 *
 */
 
kern_return_t pmsBuild(pmsDef *pd, uint32_t pdsize, pmsSetFunc_t *functab, uint32_t platformData, pmsQueryFunc_t queryFunc) {

        int steps, newsize, i, cstp, nstps, oldAltSize, xdsply;
        uint32_t setf;
        uint64_t nlimit;
        pmsDef *newpd, *oldAlt;
        boolean_t intr;

        xdsply = (pmsExperimental & 3) != 0;                    /* Turn on kprintfs if requested or in experimental mode */

        if(pdsize % sizeof(pmsDef)) return KERN_INVALID_ARGUMENT;       /* Length not multiple of definition size */
        
        steps = pdsize / sizeof(pmsDef);                                /* Get the number of steps supplied */

        if((steps >= pmsMaxStates) || (steps < pmsFree))        /* Complain if too big or too small */
                        return KERN_INVALID_ARGUMENT;                   /* Squeak loudly!!! */
                        
        if((uint32_t)functab && (uint32_t)functab[0])   /* Verify that if they supplied a new function table, entry 0 is 0 */
                return KERN_INVALID_ARGUMENT;                           /* Fail because they didn't reserve entry 0 */
                        
        if(xdsply) kprintf("\n  StepID   Down   Next    HWSel  HWfun                Limit\n");

        for(i = 0; i < steps; i++) {                                    /* Step through and verify the definitions */

                if(xdsply) kprintf("  %6d %6d %6d %08X %6d %20lld\n", pd[i].pmsStepID, pd[i].pmsDown, 
                        pd[i].pmsNext, pd[i].pmsSetCmd,
                        pd[i].sf.pmsSetFuncInd, pd[i].pmsLimit);

                if((pd[i].pmsLimit != 0) && (pd[i].pmsLimit < 100ULL)) {
                        if(xdsply) kprintf("error step %3d: pmsLimit too small/n", i);
                        return KERN_INVALID_ARGUMENT;   /* Has to be 100µS or more */
                }
                
                if((pd[i].pmsLimit != 0xFFFFFFFFFFFFFFFFULL) && (pd[i].pmsLimit > (HalfwayToForever / 1000ULL))) {
                        if(xdsply) kprintf("error step %3d: pmsLimit too big\n", i);
                        return KERN_INVALID_ARGUMENT;                   /* Can't be too big */
                }
                
                if(pd[i].pmsStepID != i) {
                        if(xdsply) kprintf("error step %3d: step ID does not match (%d)\n", i, pd[i].pmsStepID);
                        return KERN_INVALID_ARGUMENT;   /* ID must match */
                }

                if(pd[i].sf.pmsSetFuncInd >= pmsSetFuncMax) {
                        if(xdsply) kprintf("error step %3d: function invalid (%d)\n", i, pd[i].sf.pmsSetFuncInd);
                        return KERN_INVALID_ARGUMENT;   /* Fail if this function is not in the table */
                }
                
                if((pd[i].pmsDown != pmsParked) && pd[i].pmsDown >= steps) {
                        if(xdsply) kprintf("error step %3d: pmsDown out of range (%d)\n", i, pd[i].pmsDown);
                        return KERN_INVALID_ARGUMENT;   /* Step down must be in the table or park */
                }
                
                if((pd[i].pmsNext != pmsParked) && pd[i].pmsNext >= steps) {
                        if(xdsply) kprintf("error step %3d: pmsNext out of range (%d)\n", i, pd[i].pmsNext);
                        return KERN_INVALID_ARGUMENT;   /* Step up must be in the table or park */
                }
                
                if((pd[i].pmsSetCmd == pmsDelay) && (pd[i].pmsTDelay >= steps)) {
                        if(xdsply) kprintf("error step %3d: pmsTDelay out of range (%d)\n", i, pd[i].pmsTDelay);
                        return KERN_INVALID_ARGUMENT;   /* Delayed step must be in the table */
                }
                
                if((pd[i].pmsSetCmd == pmsDelay) && (pd[i].pmsLimit == 0xFFFFFFFFFFFFFFFFULL)) {
                        if(xdsply) kprintf("error step %3d: delay time limit must not be infinite\n", i);
                        return KERN_INVALID_ARGUMENT;   /* Delayed step must have a time limit */
                }
                
        }
        
/*
 *      Verify that there are no infinite synchronous forward loops in the table
 */
 
        if(xdsply) kprintf("\nInitial scan passed, start in loop check\n");
        for(i = 0; i < steps; i++) {                                    /* Start with each step. Inefficient, but who cares */
 
                cstp = i;                                                                       /* Set starting point */
                nstps = 0;                                                                      /* Initialize chain length counter */
                while(1) {                                                                      /* Do until we hit the end */
                        if(pd[cstp].pmsSetCmd == pmsParkIt) break;      /* Parking always terminates a chain so no endless loop here */
                        if(pd[cstp].pmsSetCmd == pmsDelay) break;       /* Delayed steps always terminate a chain so no endless loop here */
                        if((pd[cstp].pmsLimit != 0) && ((pd[cstp].pmsSetCmd & pmsSync) != pmsSync)) break;      /* If time limit is not 0 and not synchrouous, no endless loop */
                        if(pd[cstp].pmsNext == pmsParked) break;        /* If the next step is parked, no endless loop */
                        
                        cstp = pd[cstp].pmsNext;                                /* Chain to the next */
                        nstps = nstps + 1;                                              /* Count this step */
                        if(nstps >= steps) {                                    /* We've stepped for more steps than we have, must be an endless loop! */
                                if(xdsply) kprintf("error step %3d: infinite pmsNext loop\n", i);
                                return KERN_INVALID_ARGUMENT;           /* Suggest to our caller that they can't program... */
                        }
                }
        }
        
        if((pmsExperimental & 4) && (pmsInstalled) && ((uint32_t)functab != 0)) {       /* If we are already initted and experimental is locked in, and we are doing first */
                if(xdsply) kprintf("Experimental locked, ignoring driver pmsBuild\n");
                return KERN_RESOURCE_SHORTAGE;                          /* Just ignore the request. */
        }
        
        
        
/*
 *      Well, things look ok, let's do it to it...
 */

        if(xdsply) kprintf("Loop check passed, building and installing table\n");

        newsize = steps * sizeof(pmsDef);                               /* Get the size needed for the definition blocks */

        if(!(newpd = (pmsDef *)kalloc(newsize))) {              /* Get memory for the whole thing */
                return KERN_RESOURCE_SHORTAGE;                          /* No storage... */
        }
        
        bzero((void *)newpd, newsize);                                  /* Make it pretty */
        
/*
 *      Ok, this is it, finish intitializing, switch the tables, and pray...
 *      We want no interruptions at all and we need to lock the table.  Everybody should be parked,
 *      so no one should ever touch this.  The lock is to keep multiple builders safe.  It probably
 *      will never ever happen, but paranoia is a good thing...
 */
 
        intr = ml_set_interrupts_enabled(FALSE);                /* No interruptions in here */
        simple_lock(&pmsBuildLock);                                             /* Lock out everyone... */
        
        if(platformData) pmsPlatformData = platformData;        /* Remember the platform data word passed in if any was... */
        if((uint32_t)queryFunc) pmsQueryFunc = queryFunc;       /* Remember the query function passed in, if it was... */
        
        oldAlt = altDpmsTab;                                                    /* Remember any old alternate we had */
        oldAltSize = altDpmsTabSize;                                    /* Remember its size */

        altDpmsTab = newpd;                                                             /* Point to the new table */
        altDpmsTabSize = newsize;                                               /* Set the size */
        
        if((uint32_t)functab) {                                                 /* Did we get a new function table? */
                for(i = 0; i < pmsSetFuncMax; i++) pmsFuncTab[i] = functab[i];  /* Copy in the new table */
        }

        for(i = 0; i < pmsMaxStates; i++) pmsCtls.pmsDefs[i] = &pmsDummy;       /* Initialize the table to point to the dummy step */

        for(i = 0; i < steps; i++) {                                    /* Replace the step table entries */
                if(pd[i].pmsLimit == 0xFFFFFFFFFFFFFFFFULL) nlimit = century;   /* Default to 100 years */
                else nlimit = pd[i].pmsLimit;                           /* Otherwise use what was supplied */
                
                nanoseconds_to_absolutetime(nlimit * 1000ULL, &newpd[i].pmsLimit);      /* Convert microseconds to nanoseconds and then to ticks */
        
                setf = pd[i].sf.pmsSetFuncInd;                                  /* Make convienient */
                newpd[i].sf.pmsSetFunc = pmsFuncTab[setf];              /* Replace the index with the function address */
         
                newpd[i].pmsStepID  = pd[i].pmsStepID;          /* Set the step ID */ 
                newpd[i].pmsSetCmd  = pd[i].pmsSetCmd;          /* Set the hardware selector ID */
                newpd[i].pmsDown    = pd[i].pmsDown;            /* Set the downward step */
                newpd[i].pmsNext    = pd[i].pmsNext;            /* Set the next setp */
                newpd[i].pmsTDelay  = pd[i].pmsTDelay;          /* Set the delayed setp */
                pmsCtls.pmsDefs[i]  = &newpd[i];                        /* Copy it in */
        }
        
        pmsCtlp = (uint32_t)&pmsCtls;                                   /* Point to the new pms table */
        
        pmsInstalled = 1;                                                               /* The stepper has been born or born again... */

        simple_unlock(&pmsBuildLock);                                   /* Free play! */
        (void)ml_set_interrupts_enabled(intr);                  /* Interrupts back the way there were */

        if((uint32_t)oldAlt) kfree((vm_offset_t)oldAlt, oldAltSize);    /* If we already had an alternate, free it */

        if(xdsply) kprintf("Stepper table installed\n");
        
        return KERN_SUCCESS;                                                    /* We're in fate's hands now... */
}