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Annotation of sys/arch/i386/i386/powernow.c, Revision 1.1

1.1     ! nbrk        1: /*     $OpenBSD: powernow.c,v 1.3 2006/12/12 23:14:27 dim Exp $        */
        !             2: /*
        !             3:  * Copyright (c) 2004 Ted Unangst
        !             4:  * All rights reserved.
        !             5:  *
        !             6:  * Permission to use, copy, modify, and distribute this software for any
        !             7:  * purpose with or without fee is hereby granted, provided that the above
        !             8:  * copyright notice and this permission notice appear in all copies.
        !             9:  *
        !            10:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
        !            11:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
        !            12:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
        !            13:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            14:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
        !            15:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
        !            16:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
        !            17:  */
        !            18:
        !            19: /*
        !            20:  * AMD K6 PowerNow driver, see AMD tech doc #23525
        !            21:  * Numerous hints from Linux cpufreq driver
        !            22:  */
        !            23:
        !            24: #include <sys/param.h>
        !            25: #include <sys/sysctl.h>
        !            26:
        !            27: #include <machine/cpu.h>
        !            28: #include <machine/cpufunc.h>
        !            29: #include <machine/specialreg.h>
        !            30: #include <machine/pio.h>
        !            31:
        !            32: /* table 27 in amd 23535.  entries after 45 taken from linux cpufreq */
        !            33: struct {
        !            34:        int mult;       /* not actually used, maybe for cpuspeed */
        !            35:        int magic;
        !            36: } k6_multipliers[] = {
        !            37:        { 20, 4 },
        !            38:        { 30, 5 },
        !            39:        { 35, 7 },
        !            40:        { 40, 2 },
        !            41:        { 45, 0 },
        !            42:        { 55, 3 },
        !            43:        { 50, 1 },
        !            44:        { 60, 6 },
        !            45: };
        !            46: #define NUM_K6_ENTRIES (sizeof k6_multipliers / sizeof k6_multipliers[0])
        !            47:
        !            48: int    k6_maxindex;    /* no setting higher than this */
        !            49:
        !            50: /* linux says: "it doesn't matter where, as long as it is unused */
        !            51: #define K6PORT 0xfff0
        !            52:
        !            53: void
        !            54: k6_powernow_init(void)
        !            55: {
        !            56:        uint64_t msrval;
        !            57:        uint32_t portval;
        !            58:        int i;
        !            59:
        !            60:        /* on */
        !            61:        msrval = K6PORT | 0x1;
        !            62:        wrmsr(MSR_K6_EPMR, msrval);
        !            63:        /* read */
        !            64:        portval = inl(K6PORT + 8);
        !            65:        /* off */
        !            66:        wrmsr(MSR_K6_EPMR, 0LL);
        !            67:
        !            68:        portval = (portval >> 5) & 7;
        !            69:
        !            70:        for (i = 0; i < NUM_K6_ENTRIES; i++)
        !            71:                if (portval == k6_multipliers[i].magic) {
        !            72:                        k6_maxindex = i;
        !            73:                        break;
        !            74:                }
        !            75:        if (i == NUM_K6_ENTRIES) {
        !            76:                printf("bad value for current multiplier\n");
        !            77:                return;
        !            78:        }
        !            79:
        !            80:        cpu_setperf = k6_powernow_setperf;
        !            81: }
        !            82:
        !            83: void
        !            84: k6_powernow_setperf(int level)
        !            85: {
        !            86:        uint64_t msrval;
        !            87:        uint32_t portval;
        !            88:        int index;
        !            89:
        !            90:        index = level * k6_maxindex / 100;
        !            91:
        !            92:        /* on */
        !            93:        msrval = K6PORT | 0x1;
        !            94:        wrmsr(MSR_K6_EPMR, msrval);
        !            95:        /* read and update */
        !            96:        portval = inl(K6PORT + 8);
        !            97:        portval &= 0xf;
        !            98:        portval |= 1 << 12 | 1 << 10 | 1 << 9 |
        !            99:            k6_multipliers[index].magic << 5;
        !           100:        outl(K6PORT + 8, portval);
        !           101:        /* off */
        !           102:        wrmsr(MSR_K6_EPMR, 0LL);
        !           103: }