/*
 * Copyright (c) 2004 Martin V\xe9giard. Copyright (c) 2004-2005 Bruno Ducrot
 * Copyright (c) 2004 FUKUDA Nobuhiko <nfukuda@spa.is.uec.ac.jp> Copyright
 * (c) 2004, 2006 The NetBSD Foundation, Inc. All rights reserved.
 * 
 * This code is derived from software contributed to The NetBSD Foundation by
 * Juan Romero Pardines and Martin Vegiard.
 * 
 * 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 ``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 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.
 */
/* AMD POWERNOW K8 driver */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <bus/isa/isa.h>
#include <machine/cpu.h>
#include <machine/pmap.h>
#include <machine/pc/bios.h>
#include <machine/cpufunc.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#include <machine/vmparam.h>

#define PN8_STA_MFID(x)                 (((x) >> 16) & 0x3f)
#define PN8_STA_MVID(x)                 (((x) >> 48) & 0x1f)
#define PN8_STA_SFID(x)                 (((x) >> 8) & 0x3f)

/*
 * MSRs and bits used by PowerNow! technology
 */
#define MSR_AMDK7_FIDVID_CTL            0xc0010041
#define MSR_AMDK7_FIDVID_STATUS         0xc0010042
#define AMD_PN_FID_VID                  0x06

#define BIOS_START                      0xe0000
#define BIOS_LEN                        0x20000
#define BIOS_STEP                       16

#define PN8_PSB_VERSION                 0x14
#define PN8_PSB_TO_RVO(x)               ((x) & 0x03)
#define PN8_PSB_TO_IRT(x)               (((x) >> 2) & 0x03)
#define PN8_PSB_TO_MVS(x)               (((x) >> 4) & 0x03)
#define PN8_PSB_TO_BATT(x)              (((x) >> 6) & 0x03)
/* Bitfields used by K8 */
#define PN8_CTR_FID(x)                  ((x) & 0x3f)
#define PN8_CTR_VID(x)                  (((x) & 0x1f) << 8)
#define PN8_CTR_PENDING(x)              (((x) & 1) << 32)
#define PN8_STA_CFID(x)                 ((x) & 0x3f)
#define PN8_STA_SFID(x)                 (((x) >> 8) & 0x3f)
#define PN8_STA_MFID(x)                 (((x) >> 16) & 0x3f)
#define PN8_STA_PENDING(x)              (((x) >> 31) & 0x01)
#define PN8_STA_CVID(x)                 (((x) >> 32) & 0x1f)
#define PN8_STA_SVID(x)                 (((x) >> 40) & 0x1f)
#define PN8_STA_MVID(x)                 (((x) >> 48) & 0x1f)
#define PN8_PLL_LOCK(x)                 ((x) * 1000/5)
#define WRITE_FIDVID(fid, vid, ctrl)    \
        wrmsr(MSR_AMDK7_FIDVID_CTL,     \
            (((ctrl) << 32) | (1ULL << 16) | ((vid) << 8) | (fid)))
#define COUNT_OFF_IRT(irt)              DELAY(10 * (1 << (irt)))
#define COUNT_OFF_VST(vst)              DELAY(20 * (vst))
#define FID_TO_VCO_FID(fid)             \
        (((fid) < 8) ? (8 + ((fid) << 1)) : (fid))

#define READ_PENDING_WAIT(status)                               \
        do {                                                    \
                (status) = rdmsr(MSR_AMDK7_FIDVID_STATUS);      \
        } while (PN8_STA_PENDING(status))
#define abs(x) ( (x) < 0 ? -(x) : (x) )

#define POWERNOW_MAX_STATES             16

struct k8pnow_state {
        int             freq;
        uint8_t         fid;
        uint8_t         vid;
};

struct k8pnow_cpu_state {
        struct k8pnow_state state_table[POWERNOW_MAX_STATES];
        unsigned int    n_states;
        unsigned int    vst;
        unsigned int    mvs;
        unsigned int    pll;
        unsigned int    rvo;
        unsigned int    irt;
        int             low;
};

struct psb_s {
        char            signature [10]; /* AMDK7PNOW! */
        uint8_t         version;
        uint8_t         flags;
        uint16_t        ttime;  /* Min Settling time */
        uint8_t         reserved;
        uint8_t         n_pst;
};
struct pst_s {
        uint32_t        cpuid;
        uint8_t         pll;
        uint8_t         fid;
        uint8_t         vid;
        uint8_t         n_states;
};

static struct k8pnow_cpu_state *k8pnow_current_state = NULL;
int             cpuspeed;

int
k8pnow_states(struct k8pnow_cpu_state *cstate, uint32_t cpusig,
              unsigned int fid, unsigned int vid);
int
                k8pnow_decode_pst(struct k8pnow_cpu_state *cstate, uint8_t * p);

/*
 * Given a set of pair of fid/vid, and number of performance states, compute
 * state_table via an insertion sort.
 */
int
k8pnow_decode_pst(struct k8pnow_cpu_state *cstate, uint8_t * p)
{
        int             i         , j, n;
        struct k8pnow_state state;
        for (n = 0, i = 0; i < cstate->n_states; i++) {
                state.fid = *p++;
                state.vid = *p++;

                /*
                 * The minimum supported frequency per the data sheet is
                 * 800MHz The maximum supported frequency is 5000MHz.
                 */
                state.freq = 800 + state.fid * 100;
                j = n;
                while (j > 0 && cstate->state_table[j - 1].freq > state.freq) {
                        memcpy(&cstate->state_table[j],
                               &cstate->state_table[j - 1],
                               sizeof(struct k8pnow_state));
                        --j;
                }
                memcpy(&cstate->state_table[j], &state,
                       sizeof(struct k8pnow_state));
                n++;
        }
        return 1;
}

int
k8pnow_states(struct k8pnow_cpu_state *cstate, uint32_t cpusig,
              unsigned int fid, unsigned int vid)
{
        struct psb_s   *psb;
        struct pst_s   *pst;
        uint8_t        *p;
        int             i;
        for (p = (u_int8_t *) BIOS_PADDRTOVADDR(BIOS_START);
             p < (u_int8_t *) BIOS_PADDRTOVADDR(BIOS_START + BIOS_LEN); p +=
             BIOS_STEP) {
                if (memcmp(p, "AMDK7PNOW!", 10) == 0) {
                        psb = (struct psb_s *)p;
                        if (psb->version != PN8_PSB_VERSION)
                                return 0;
                        cstate->vst = psb->ttime;
                        cstate->rvo = PN8_PSB_TO_RVO(psb->reserved);
                        cstate->irt = PN8_PSB_TO_IRT(psb->reserved);
                        cstate->mvs = PN8_PSB_TO_MVS(psb->reserved);
                        cstate->low = PN8_PSB_TO_BATT(psb->reserved);
                        p += sizeof(struct psb_s);
                        for (i = 0; i < psb->n_pst; ++i) {
                                pst = (struct pst_s *)p;
                                cstate->pll = pst->pll;
                                cstate->n_states = pst->n_states;
                                if (cpusig == pst->cpuid &&
                                    pst->fid == fid && pst->vid == vid) {
                                        return (k8pnow_decode_pst(cstate,
                                                p += sizeof(struct pst_s)));
                                }
                                p += sizeof(struct pst_s) + 2
                                        * cstate->n_states;
                        }
                }
        }
        return 0;
}

static int
k8_get_curfreq(void)
{
        unsigned int    i;
        uint64_t        status;
        int             cfid, cvid;
        struct k8pnow_cpu_state *cstate;
        status = rdmsr(MSR_AMDK7_FIDVID_STATUS);
        if (PN8_STA_PENDING(status))
                return 1;
        cfid = PN8_STA_CFID(status);
        cvid = PN8_STA_CVID(status);
        cstate = k8pnow_current_state;
        for (i = 0; i < cstate->n_states; i++) {
                if (cstate->state_table[i].fid == cfid &&
                    cstate->state_table[i].vid == cvid)
                        return (cstate->state_table[i].freq);
        }
        /* Not reached */
        return -1;
}

static int
k8_powernow_setperf(unsigned int freq)
{
        unsigned int    i;
        uint64_t        status;
        uint32_t        val;
        int             cfid      , cvid, fid = 0, vid = 0;
        int             rvo;
        struct k8pnow_cpu_state *cstate;
        /*
         * We dont do a k8pnow_read_pending_wait here, need to ensure that
         * the change pending bit isn't stuck,
         */
        status = rdmsr(MSR_AMDK7_FIDVID_STATUS);
        if (PN8_STA_PENDING(status))
                return 1;
        cfid = PN8_STA_CFID(status);
        cvid = PN8_STA_CVID(status);
        cstate = k8pnow_current_state;
        for (i = 0; i < cstate->n_states; i++) {
                if (cstate->state_table[i].freq >= freq) {
                        fid = cstate->state_table[i].fid;
                        vid = cstate->state_table[i].vid;
                        break;
                }
        }
        if (fid == cfid && vid == cvid) {
                cpuspeed = freq;
                return 0;
        }
        /*
         * Phase 1: Raise core voltage to requested VID if frequency is going
         * up.
         */
        while (cvid > vid) {
                val = cvid - (1 << cstate->mvs);
                WRITE_FIDVID(cfid, (val > 0) ? val : 0, 1ULL);
                READ_PENDING_WAIT(status);
                cvid = PN8_STA_CVID(status);
                COUNT_OFF_VST(cstate->vst);
        }

        /* ... then raise to voltage + RVO (if required) */
        for (rvo = cstate->rvo; rvo > 0 && cvid > 0; --rvo) {
                /*
                 * XXX It's not clear from spec if we have to do that in 0.25
                 * step or in MVS.  Therefore do it as it's done under Linux
                 */
                WRITE_FIDVID(cfid, cvid - 1, 1ULL);
                READ_PENDING_WAIT(status);
                cvid = PN8_STA_CVID(status);
                COUNT_OFF_VST(cstate->vst);
        }
        /* Phase 2: change to requested core frequency */
        if (cfid != fid) {
                uint32_t        vco_fid, vco_cfid;
                vco_fid = FID_TO_VCO_FID(fid);
                vco_cfid = FID_TO_VCO_FID(cfid);
                while (abs(vco_fid - vco_cfid) > 2) {
                        if (fid > cfid) {
                                if (cfid > 6)
                                        val = cfid + 2;
                                else
                                        val = FID_TO_VCO_FID(cfid) + 2;
                        } else
                                val = cfid - 2;
                        WRITE_FIDVID(val, cvid, (uint64_t) cstate->pll * 1000 / 5);
                        READ_PENDING_WAIT(status);
                        cfid = PN8_STA_CFID(status);
                        COUNT_OFF_IRT(cstate->irt);
                        vco_cfid = FID_TO_VCO_FID(cfid);
                }
                WRITE_FIDVID(fid, cvid, (uint64_t) cstate->pll * 1000 / 5);
                READ_PENDING_WAIT(status);
                cfid = PN8_STA_CFID(status);
                COUNT_OFF_IRT(cstate->irt);
        }
        /* Phase 3: change to requested voltage */
        if (cvid != vid) {
                WRITE_FIDVID(cfid, vid, 1ULL);
                READ_PENDING_WAIT(status);
                cvid = PN8_STA_CVID(status);
                COUNT_OFF_VST(cstate->vst);
        }
        if (cfid == fid || cvid == vid)
                cpuspeed = cstate->state_table[i].freq;
        return 0;
}

static int
powernow_sysctl_helper(SYSCTL_HANDLER_ARGS)
{
        int             fq        , err = 0;
        int             i;
        struct k8pnow_cpu_state *cstate;
        struct k8pnow_state *state;
        cstate = k8pnow_current_state;
        if (req->newptr != NULL) {
                err = SYSCTL_IN(req, &fq, sizeof(fq));
                if (err)
                        return err;
                if (fq != cpuspeed) {
                        for (i = cstate->n_states; i > 0; i--) {
                                state = &cstate->state_table[i - 1];
                                if (fq == state->freq) {
                                        k8_powernow_setperf(fq);
                                        break;
                                }
                        }
                }
        } else {
                err = SYSCTL_OUT(req, &cpuspeed, sizeof(cpuspeed));
        }
        return err;
}

static struct sysctl_ctx_list machdep_powernow_ctx;
static char     freqs_available[80];

static int
powernow_init(void)
{
        uint64_t        status;
        size_t          len    , freq_len;
        uint32_t        maxfid, maxvid, i;
        struct k8pnow_cpu_state *cstate;
        struct k8pnow_state *state;
        const char     *techname;
        u_int32_t       regs  [4];
        cpuspeed = 0;
        struct sysctl_oid *oid, *leaf;

        do_cpuid(0x80000000, regs);
        if (regs[0] < 0x80000007)
                return 1;
        do_cpuid(0x80000007, regs);
        if (!(regs[3] & AMD_PN_FID_VID))
                return 2;
        /* Extended CPUID signature value */
        do_cpuid(0x80000001, regs);
        cstate = kmalloc(sizeof(struct k8pnow_cpu_state), M_DEVBUF, M_WAITOK);
        cstate->n_states = 0;

        status = rdmsr(MSR_AMDK7_FIDVID_STATUS);
        maxfid = PN8_STA_MFID(status);
        maxvid = PN8_STA_MVID(status);

        if (PN8_STA_SFID(status) != PN8_STA_MFID(status))
                techname = "PowerNow!";
        else
                techname = "Cool`n'Quiet";
        k8pnow_states(cstate, regs[0], maxfid, maxvid);
        len = 0;
        if (cstate->n_states) {
                freq_len = cstate->n_states * (sizeof("9999 ") - 1) + 1;
                kprintf("%s speeds:",
                        techname);
                for (i = cstate->n_states; i > 0; i--) {
                        state = &cstate->state_table[i - 1];
                        kprintf(" %d", state->freq);
                        len += ksnprintf(freqs_available + len, freq_len - len, "%d%s",
                                         state->freq,
                                         i > 1 ? " " : "");
                }
                kprintf(" MHz\n");
                k8pnow_current_state = cstate;
                k8_powernow_setperf(k8_get_curfreq());
        } else {
                kfree(cstate, M_DEVBUF);
                kprintf("powernow: no power states found\n");
                return 3;
        }

        /*
         * Setup the sysctl sub-tree machdep.powernow.*
         */
        oid = SYSCTL_ADD_NODE(&machdep_powernow_ctx,
                     SYSCTL_STATIC_CHILDREN(_machdep), OID_AUTO, "powernow",
                              CTLFLAG_RD, NULL, "");
        if (oid == NULL)
                return (EOPNOTSUPP);
        oid = SYSCTL_ADD_NODE(&machdep_powernow_ctx, SYSCTL_CHILDREN(oid),
                              OID_AUTO, "frequency", CTLFLAG_RD, NULL, "");
        if (oid == NULL)
                return (EOPNOTSUPP);
        leaf = SYSCTL_ADD_PROC(&machdep_powernow_ctx, SYSCTL_CHILDREN(oid),
                      OID_AUTO, "target", CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
                               powernow_sysctl_helper, "I",
                               "Target CPU frequency for AMD PowerNow!");
        if (leaf == NULL)
                return (EOPNOTSUPP);
        leaf = SYSCTL_ADD_PROC(&machdep_powernow_ctx, SYSCTL_CHILDREN(oid),
                     OID_AUTO, "current", CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
                               powernow_sysctl_helper, "I",
                               "Current CPU frequency for AMD PowerNow!");
        if (leaf == NULL)
                return (EOPNOTSUPP);
        leaf = SYSCTL_ADD_STRING(&machdep_powernow_ctx, SYSCTL_CHILDREN(oid),
                         OID_AUTO, "available", CTLFLAG_RD, freqs_available,
                                 sizeof(freqs_available),
                              "CPU frequencies supported by AMD PowerNow!");
        if (leaf == NULL)
                return (EOPNOTSUPP);
        return (0);
}

static int
powernow_modevh(struct module *m, int what, void *arg __unused)
{
        int             error;

        switch (what) {
        case MOD_LOAD:
                error = sysctl_ctx_init(&machdep_powernow_ctx);
                if (error != 0)
                        break;
                error = powernow_init();
                break;
        case MOD_UNLOAD:
                if (k8pnow_current_state)
                        kfree(k8pnow_current_state, M_DEVBUF);
                error = sysctl_ctx_free(&machdep_powernow_ctx);
                break;
        default:
                error = EINVAL;
                break;
        }
        return (error);
}
static moduledata_t powernow_mod = {
        "powernow",
        powernow_modevh,
        NULL,
};

DECLARE_MODULE(powernow, powernow_mod, SI_BOOT2_KLD, SI_ORDER_ANY);