/*-
 * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/i386/i386/i686_mem.c,v 1.24 2004/07/01 07:46:28 jhb Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/memrange.h>
#include <sys/smp.h>
#include <sys/sysctl.h>

#include <machine/md_var.h>
#include <machine/specialreg.h>

/*
 * i686 memory range operations
 *
 * This code will probably be impenetrable without reference to the
 * Intel Pentium Pro documentation.
 */

static char *mem_owner_bios = "BIOS";

#define MR686_FIXMTRR	(1<<0)

#define mrwithin(mr, a) \
    (((a) >= (mr)->mr_base) && ((a) < ((mr)->mr_base + (mr)->mr_len)))
#define mroverlap(mra, mrb) \
    (mrwithin(mra, mrb->mr_base) || mrwithin(mrb, mra->mr_base))

#define mrvalid(base, len) 						\
    ((!(base & ((1 << 12) - 1))) && 	/* base is multiple of 4k */	\
     ((len) >= (1 << 12)) && 		/* length is >= 4k */		\
     powerof2((len)) && 		/* ... and power of two */	\
     !((base) & ((len) - 1)))		/* range is not discontiuous */

#define mrcopyflags(curr, new) (((curr) & ~MDF_ATTRMASK) | ((new) & MDF_ATTRMASK))

static int			mtrrs_disabled;
TUNABLE_INT("machdep.disable_mtrrs", &mtrrs_disabled);
SYSCTL_INT(_machdep, OID_AUTO, disable_mtrrs, CTLFLAG_RDTUN,
	&mtrrs_disabled, 0, "Disable i686 MTRRs.");

static void			i686_mrinit(struct mem_range_softc *sc);
static int			i686_mrset(struct mem_range_softc *sc,
					   struct mem_range_desc *mrd,
					   int *arg);
static void			i686_mrAPinit(struct mem_range_softc *sc);

static struct mem_range_ops i686_mrops = {
    i686_mrinit,
    i686_mrset,
    i686_mrAPinit
};

/* XXX for AP startup hook */
static u_int64_t		mtrrcap, mtrrdef;

static struct mem_range_desc	*mem_range_match(struct mem_range_softc *sc,
						 struct mem_range_desc *mrd);
static void			i686_mrfetch(struct mem_range_softc *sc);
static int			i686_mtrrtype(int flags);
static int			i686_mrt2mtrr(int flags, int oldval);
static int			i686_mtrrconflict(int flag1, int flag2);
static void			i686_mrstore(struct mem_range_softc *sc);
static void			i686_mrstoreone(void *arg);
static struct mem_range_desc	*i686_mtrrfixsearch(struct mem_range_softc *sc,
						    u_int64_t addr);
static int			i686_mrsetlow(struct mem_range_softc *sc,
					      struct mem_range_desc *mrd,
					      int *arg);
static int			i686_mrsetvariable(struct mem_range_softc *sc,
						   struct mem_range_desc *mrd,
						   int *arg);

/* i686 MTRR type to memory range type conversion */
static int i686_mtrrtomrt[] = {
    MDF_UNCACHEABLE,
    MDF_WRITECOMBINE,
    MDF_UNKNOWN,
    MDF_UNKNOWN,
    MDF_WRITETHROUGH,
    MDF_WRITEPROTECT,
    MDF_WRITEBACK
};

#define MTRRTOMRTLEN (sizeof(i686_mtrrtomrt) / sizeof(i686_mtrrtomrt[0]))

static int
i686_mtrr2mrt(int val) {
	if (val < 0 || val >= MTRRTOMRTLEN)
		return MDF_UNKNOWN;
	return i686_mtrrtomrt[val];
}

/* 
 * i686 MTRR conflicts. Writeback and uncachable may overlap.
 */
static int
i686_mtrrconflict(int flag1, int flag2) {
	flag1 &= MDF_ATTRMASK;
	flag2 &= MDF_ATTRMASK;
	if (flag1 == flag2 ||
	    (flag1 == MDF_WRITEBACK && flag2 == MDF_UNCACHEABLE) ||
	    (flag2 == MDF_WRITEBACK && flag1 == MDF_UNCACHEABLE))
		return 0;
	return 1;
}

/*
 * Look for an exactly-matching range.
 */
static struct mem_range_desc *
mem_range_match(struct mem_range_softc *sc, struct mem_range_desc *mrd) 
{
    struct mem_range_desc	*cand;
    int				i;
	
    for (i = 0, cand = sc->mr_desc; i < sc->mr_ndesc; i++, cand++)
	if ((cand->mr_base == mrd->mr_base) &&
	    (cand->mr_len == mrd->mr_len))
	    return(cand);
    return(NULL);
}

/*
 * Fetch the current mtrr settings from the current CPU (assumed to all
 * be in sync in the SMP case).  Note that if we are here, we assume
 * that MTRRs are enabled, and we may or may not have fixed MTRRs.
 */
static void
i686_mrfetch(struct mem_range_softc *sc)
{
    struct mem_range_desc	*mrd;
    u_int64_t			msrv;
    int				i, j, msr;

    mrd = sc->mr_desc;

    /* Get fixed-range MTRRs */
    if (sc->mr_cap & MR686_FIXMTRR) {
	msr = MSR_MTRR64kBase;
	for (i = 0; i < (MTRR_N64K / 8); i++, msr++) {
	    msrv = rdmsr(msr);
	    for (j = 0; j < 8; j++, mrd++) {
		mrd->mr_flags = (mrd->mr_flags & ~MDF_ATTRMASK) |
		    i686_mtrr2mrt(msrv & 0xff) |
		    MDF_ACTIVE;
		if (mrd->mr_owner[0] == 0)
		    strcpy(mrd->mr_owner, mem_owner_bios);
		msrv = msrv >> 8;
	    }
	}
	msr = MSR_MTRR16kBase;
	for (i = 0; i < (MTRR_N16K / 8); i++, msr++) {
	    msrv = rdmsr(msr);
	    for (j = 0; j < 8; j++, mrd++) {
		mrd->mr_flags = (mrd->mr_flags & ~MDF_ATTRMASK) |
		    i686_mtrr2mrt(msrv & 0xff) |
		    MDF_ACTIVE;
		if (mrd->mr_owner[0] == 0)
		    strcpy(mrd->mr_owner, mem_owner_bios);
		msrv = msrv >> 8;
	    }
	}
	msr = MSR_MTRR4kBase;
	for (i = 0; i < (MTRR_N4K / 8); i++, msr++) {
	    msrv = rdmsr(msr);
	    for (j = 0; j < 8; j++, mrd++) {
		mrd->mr_flags = (mrd->mr_flags & ~MDF_ATTRMASK) |
		    i686_mtrr2mrt(msrv & 0xff) |
		    MDF_ACTIVE;
		if (mrd->mr_owner[0] == 0)
		    strcpy(mrd->mr_owner, mem_owner_bios);
		msrv = msrv >> 8;
	    }
	}
    }

    /* Get remainder which must be variable MTRRs */
    msr = MSR_MTRRVarBase;
    for (; (mrd - sc->mr_desc) < sc->mr_ndesc; msr += 2, mrd++) {
	msrv = rdmsr(msr);
	mrd->mr_flags = (mrd->mr_flags & ~MDF_ATTRMASK) |
	    i686_mtrr2mrt(msrv & 0xff);
	mrd->mr_base = msrv & 0x0000000ffffff000LL;
	msrv = rdmsr(msr + 1);
	mrd->mr_flags = (msrv & 0x800) ? 
	    (mrd->mr_flags | MDF_ACTIVE) :
	    (mrd->mr_flags & ~MDF_ACTIVE);
	/* Compute the range from the mask. Ick. */
	mrd->mr_len = (~(msrv & 0x0000000ffffff000LL) & 0x0000000fffffffffLL) + 1;
	if (!mrvalid(mrd->mr_base, mrd->mr_len))
	    mrd->mr_flags |= MDF_BOGUS;
	/* If unclaimed and active, must be the BIOS */
	if ((mrd->mr_flags & MDF_ACTIVE) && (mrd->mr_owner[0] == 0))
	    strcpy(mrd->mr_owner, mem_owner_bios);
    }
}

/*
 * Return the MTRR memory type matching a region's flags
 */
static int
i686_mtrrtype(int flags)
{
    int		i;

    flags &= MDF_ATTRMASK;

    for (i = 0; i < MTRRTOMRTLEN; i++) {
	if (i686_mtrrtomrt[i] == MDF_UNKNOWN)
	    continue;
	if (flags == i686_mtrrtomrt[i])
	    return(i);
    }
    return(-1);
}

static int
i686_mrt2mtrr(int flags, int oldval)
{
	int val;

	if ((val = i686_mtrrtype(flags)) == -1)
		return oldval & 0xff;
	return val & 0xff;
}

/*
 * Update running CPU(s) MTRRs to match the ranges in the descriptor
 * list.
 *
 * XXX Must be called with interrupts enabled.
 */
static void
i686_mrstore(struct mem_range_softc *sc)
{
#ifdef SMP
    /*
     * We should use ipi_all_but_self() to call other CPUs into a 
     * locking gate, then call a target function to do this work.
     * The "proper" solution involves a generalised locking gate
     * implementation, not ready yet.
     */
    smp_rendezvous(NULL, i686_mrstoreone, NULL, (void *)sc);
#else
    disable_intr();				/* disable interrupts */
    i686_mrstoreone((void *)sc);
    enable_intr();
#endif
}

/*
 * Update the current CPU's MTRRs with those represented in the
 * descriptor list.  Note that we do this wholesale rather than
 * just stuffing one entry; this is simpler (but slower, of course).
 */
static void
i686_mrstoreone(void *arg)
{
    struct mem_range_softc 	*sc = (struct mem_range_softc *)arg;
    struct mem_range_desc	*mrd;
    u_int64_t			omsrv, msrv;
    int				i, j, msr;
    u_int			cr4save;

    mrd = sc->mr_desc;

    cr4save = rcr4();				/* save cr4 */
    if (cr4save & CR4_PGE)
	load_cr4(cr4save & ~CR4_PGE);
    load_cr0((rcr0() & ~CR0_NW) | CR0_CD);	/* disable caches (CD = 1, NW = 0) */
    wbinvd();					/* flush caches, TLBs */
    wrmsr(MSR_MTRRdefType, rdmsr(MSR_MTRRdefType) & ~0x800);	/* disable MTRRs (E = 0) */

    /* Set fixed-range MTRRs */
    if (sc->mr_cap & MR686_FIXMTRR) {
	msr = MSR_MTRR64kBase;
	for (i = 0; i < (MTRR_N64K / 8); i++, msr++) {
	    msrv = 0;
	    omsrv = rdmsr(msr);
	    for (j = 7; j >= 0; j--) {
		msrv = msrv << 8;
		msrv |= i686_mrt2mtrr((mrd + j)->mr_flags, omsrv >> (j*8));
	    }
	    wrmsr(msr, msrv);
	    mrd += 8;
	}
	msr = MSR_MTRR16kBase;
	for (i = 0; i < (MTRR_N16K / 8); i++, msr++) {
	    msrv = 0;
	    omsrv = rdmsr(msr);
	    for (j = 7; j >= 0; j--) {
		msrv = msrv << 8;
		msrv |= i686_mrt2mtrr((mrd + j)->mr_flags, omsrv >> (j*8));
	    }
	    wrmsr(msr, msrv);
	    mrd += 8;
	}
	msr = MSR_MTRR4kBase;
	for (i = 0; i < (MTRR_N4K / 8); i++, msr++) {
	    msrv = 0;
	    omsrv = rdmsr(msr);
	    for (j = 7; j >= 0; j--) {
		msrv = msrv << 8;
		msrv |= i686_mrt2mtrr((mrd + j)->mr_flags, omsrv >> (j*8));
	    }
	    wrmsr(msr, msrv);
	    mrd += 8;
	}
    }

    /* Set remainder which must be variable MTRRs */
    msr = MSR_MTRRVarBase;
    for (; (mrd - sc->mr_desc) < sc->mr_ndesc; msr += 2, mrd++) {
	/* base/type register */
	omsrv = rdmsr(msr);
	if (mrd->mr_flags & MDF_ACTIVE) {
	    msrv = mrd->mr_base & 0x0000000ffffff000LL;
	    msrv |= i686_mrt2mtrr(mrd->mr_flags, omsrv);
	} else {
	    msrv = 0;
	}
	wrmsr(msr, msrv);	
	    
	/* mask/active register */
	if (mrd->mr_flags & MDF_ACTIVE) {
	    msrv = 0x800 | (~(mrd->mr_len - 1) & 0x0000000ffffff000LL);
	} else {
	    msrv = 0;
	}
	wrmsr(msr + 1, msrv);
    }
    wbinvd();							/* flush caches, TLBs */
    wrmsr(MSR_MTRRdefType, rdmsr(MSR_MTRRdefType) | 0x800);	/* restore MTRR state */
    load_cr0(rcr0() & ~(CR0_CD | CR0_NW));  			/* enable caches CD = 0 and NW = 0 */
    load_cr4(cr4save);						/* restore cr4 */
}

/*
 * Hunt for the fixed MTRR referencing (addr)
 */
static struct mem_range_desc *
i686_mtrrfixsearch(struct mem_range_softc *sc, u_int64_t addr)
{
    struct mem_range_desc *mrd;
    int			i;
    
    for (i = 0, mrd = sc->mr_desc; i < (MTRR_N64K + MTRR_N16K + MTRR_N4K); i++, mrd++)
	if ((addr >= mrd->mr_base) && (addr < (mrd->mr_base + mrd->mr_len)))
	    return(mrd);
    return(NULL);
}

/*
 * Try to satisfy the given range request by manipulating the fixed MTRRs that
 * cover low memory.
 *
 * Note that we try to be generous here; we'll bloat the range out to the 
 * next higher/lower boundary to avoid the consumer having to know too much
 * about the mechanisms here.
 *
 * XXX note that this will have to be updated when we start supporting "busy" ranges.
 */
static int
i686_mrsetlow(struct mem_range_softc *sc, struct mem_range_desc *mrd, int *arg)
{
    struct mem_range_desc	*first_md, *last_md, *curr_md;

    /* range check */
    if (((first_md = i686_mtrrfixsearch(sc, mrd->mr_base)) == NULL) ||
	((last_md = i686_mtrrfixsearch(sc, mrd->mr_base + mrd->mr_len - 1)) == NULL))
	return(EINVAL);

    /* check we aren't doing something risky */
    if (!(mrd->mr_flags & MDF_FORCE))
	for (curr_md = first_md; curr_md <= last_md; curr_md++) {
	    if ((curr_md->mr_flags & MDF_ATTRMASK) == MDF_UNKNOWN)
		return (EACCES);
	}

    /* set flags, clear set-by-firmware flag */
    for (curr_md = first_md; curr_md <= last_md; curr_md++) {
	curr_md->mr_flags = mrcopyflags(curr_md->mr_flags & ~MDF_FIRMWARE, mrd->mr_flags);
	bcopy(mrd->mr_owner, curr_md->mr_owner, sizeof(mrd->mr_owner));
    }

    return(0);
}


/*
 * Modify/add a variable MTRR to satisfy the request.
 *
 * XXX needs to be updated to properly support "busy" ranges.
 */
static int
i686_mrsetvariable(struct mem_range_softc *sc, struct mem_range_desc *mrd, int *arg)
{
    struct mem_range_desc	*curr_md, *free_md;
    int				i;
    
    /* 
     * Scan the currently active variable descriptors, look for 
     * one we exactly match (straight takeover) and for possible
     * accidental overlaps.
     * Keep track of the first empty variable descriptor in case we
     * can't perform a takeover.
     */
    i = (sc->mr_cap & MR686_FIXMTRR) ? MTRR_N64K + MTRR_N16K + MTRR_N4K : 0;
    curr_md = sc->mr_desc + i;
    free_md = NULL;
    for (; i < sc->mr_ndesc; i++, curr_md++) {
	if (curr_md->mr_flags & MDF_ACTIVE) {
	    /* exact match? */
	    if ((curr_md->mr_base == mrd->mr_base) &&
		(curr_md->mr_len == mrd->mr_len)) {
		/* whoops, owned by someone */
		if (curr_md->mr_flags & MDF_BUSY)
		    return(EBUSY);
		/* check we aren't doing something risky */
		if (!(mrd->mr_flags & MDF_FORCE) &&
		  ((curr_md->mr_flags & MDF_ATTRMASK) == MDF_UNKNOWN))
		    return (EACCES);
		/* Ok, just hijack this entry */
		free_md = curr_md;
		break;
	    }
	    /* non-exact overlap ? */
	    if (mroverlap(curr_md, mrd)) {
		/* between conflicting region types? */
		if (i686_mtrrconflict(curr_md->mr_flags, mrd->mr_flags))
		    return(EINVAL);
	    }
	} else if (free_md == NULL) {
	    free_md = curr_md;
	}
    }
    /* got somewhere to put it? */
    if (free_md == NULL)
	return(ENOSPC);

    /* Set up new descriptor */
    free_md->mr_base = mrd->mr_base;
    free_md->mr_len = mrd->mr_len;
    free_md->mr_flags = mrcopyflags(MDF_ACTIVE, mrd->mr_flags);
    bcopy(mrd->mr_owner, free_md->mr_owner, sizeof(mrd->mr_owner));
    return(0);
}

/*
 * Handle requests to set memory range attributes by manipulating MTRRs.
 *
 */
static int
i686_mrset(struct mem_range_softc *sc, struct mem_range_desc *mrd, int *arg)
{
    struct mem_range_desc	*targ;
    int				error = 0;

    switch(*arg) {
    case MEMRANGE_SET_UPDATE:
	/* make sure that what's being asked for is even possible at all */
	if (!mrvalid(mrd->mr_base, mrd->mr_len) ||
	    i686_mtrrtype(mrd->mr_flags) == -1)
	    return(EINVAL);

#define FIXTOP	((MTRR_N64K * 0x10000) + (MTRR_N16K * 0x4000) + (MTRR_N4K * 0x1000))

	/* are the "low memory" conditions applicable? */
	if ((sc->mr_cap & MR686_FIXMTRR) &&
	    ((mrd->mr_base + mrd->mr_len) <= FIXTOP)) {
	    if ((error = i686_mrsetlow(sc, mrd, arg)) != 0)
		return(error);
	} else {
	    /* it's time to play with variable MTRRs */
	    if ((error = i686_mrsetvariable(sc, mrd, arg)) != 0)
		return(error);
	}
	break;

    case MEMRANGE_SET_REMOVE:
	if ((targ = mem_range_match(sc, mrd)) == NULL)
	    return(ENOENT);
	if (targ->mr_flags & MDF_FIXACTIVE)
	    return(EPERM);
	if (targ->mr_flags & MDF_BUSY)
	    return(EBUSY);
	targ->mr_flags &= ~MDF_ACTIVE;
	targ->mr_owner[0] = 0;
	break;

    default:
	return(EOPNOTSUPP);
    }

    /* update the hardware */
    i686_mrstore(sc);
    i686_mrfetch(sc);	/* refetch to see where we're at */
    return(0);
}

/*
 * Work out how many ranges we support, initialise storage for them, 
 * fetch the initial settings.
 */
static void
i686_mrinit(struct mem_range_softc *sc)
{
    struct mem_range_desc	*mrd;
    int				nmdesc = 0;
    int				i;

    mtrrcap = rdmsr(MSR_MTRRcap);
    mtrrdef = rdmsr(MSR_MTRRdefType);

    /* For now, bail out if MTRRs are not enabled */
    if (!(mtrrdef & 0x800)) {
	if (bootverbose)
	    printf("CPU supports MTRRs but not enabled\n");
	return;
    }
    nmdesc = mtrrcap & 0xff;
    if (bootverbose)
	printf("Pentium Pro MTRR support enabled\n");

    /* If fixed MTRRs supported and enabled */
    if ((mtrrcap & 0x100) && (mtrrdef & 0x400)) {
	sc->mr_cap = MR686_FIXMTRR;
	nmdesc += MTRR_N64K + MTRR_N16K + MTRR_N4K;
    }

    sc->mr_desc = 
	(struct mem_range_desc *)malloc(nmdesc * sizeof(struct mem_range_desc), 
					M_MEMDESC, M_WAITOK | M_ZERO);
    sc->mr_ndesc = nmdesc;

    mrd = sc->mr_desc;

    /* Populate the fixed MTRR entries' base/length */
    if (sc->mr_cap & MR686_FIXMTRR) {
	for (i = 0; i < MTRR_N64K; i++, mrd++) {
	    mrd->mr_base = i * 0x10000;
	    mrd->mr_len = 0x10000;
	    mrd->mr_flags = MDF_FIXBASE | MDF_FIXLEN | MDF_FIXACTIVE;
	}
	for (i = 0; i < MTRR_N16K; i++, mrd++) {
	    mrd->mr_base = i * 0x4000 + 0x80000;
	    mrd->mr_len = 0x4000;
	    mrd->mr_flags = MDF_FIXBASE | MDF_FIXLEN | MDF_FIXACTIVE;
	}
	for (i = 0; i < MTRR_N4K; i++, mrd++) {
	    mrd->mr_base = i * 0x1000 + 0xc0000;
	    mrd->mr_len = 0x1000;
	    mrd->mr_flags = MDF_FIXBASE | MDF_FIXLEN | MDF_FIXACTIVE;
	}
    }

    /* 
     * Get current settings, anything set now is considered to have 
     * been set by the firmware. (XXX has something already played here?)
     */
    i686_mrfetch(sc);
    mrd = sc->mr_desc;
    for (i = 0; i < sc->mr_ndesc; i++, mrd++) {
	if (mrd->mr_flags & MDF_ACTIVE)
	    mrd->mr_flags |= MDF_FIRMWARE;
    }
}

/*
 * Initialise MTRRs on an AP after the BSP has run the init code.
 */
static void
i686_mrAPinit(struct mem_range_softc *sc)
{
    i686_mrstoreone((void *)sc);	/* set MTRRs to match BSP */
    wrmsr(MSR_MTRRdefType, mtrrdef);	/* set MTRR behaviour to match BSP */
}

static void
i686_mem_drvinit(void *unused)
{
    /* Try for i686 MTRRs */
    if (!mtrrs_disabled && (cpu_feature & CPUID_MTRR) &&
	((cpu_id & 0xf00) == 0x600 || (cpu_id & 0xf00) == 0xf00) &&
	((strcmp(cpu_vendor, "GenuineIntel") == 0) ||
	(strcmp(cpu_vendor, "AuthenticAMD") == 0))) {
	mem_range_softc.mr_op = &i686_mrops;
    }
}

SYSINIT(i686memdev,SI_SUB_DRIVERS,SI_ORDER_FIRST,i686_mem_drvinit,NULL)
