/*      $NetBSD: cpu_speedctl.c,v 1.3 2020/07/06 10:58:06 rin Exp $ */

/*-
 * Copyright (c) 2006 Michael Lorenz
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__KERNEL_RCSID(0, "$NetBSD: cpu_speedctl.c,v 1.3 2020/07/06 10:58:06 rin Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/types.h>

#include <powerpc/psl.h>
#include <powerpc/spr.h>
#include <powerpc/oea/cpufeat.h>
#include <powerpc/oea/spr.h>

#include <sys/sysctl.h>
#include <dev/ofw/openfirm.h>

void init_scom_speedctl(void);
static int scom_speedctl = 0;
static uint32_t scom_speeds[2];
static uint32_t scom_reg[2];
static int  sysctl_cpuspeed_temp(SYSCTLFN_ARGS);
static int  sysctl_cpuspeed_cur(SYSCTLFN_ARGS);
static int  sysctl_cpuspeed_available(SYSCTLFN_ARGS);

void
init_scom_speedctl(void)
{
        int node;
        const struct sysctlnode *sysctl_node, *me, *freq;

        /* do this only once */
        if (scom_speedctl != 0) return;
        scom_speedctl = 1;

        node = OF_finddevice("/cpus/@0");
        if (OF_getprop(node, "power-mode-data", scom_reg, 8) != 8)
                return;
        if (OF_getprop(node, "clock-frequency", scom_speeds, 4) != 4)
                return;
        scom_speeds[0] = scom_speeds[0] / 1000000; /* Hz -> MHz */
        scom_speeds[1] = scom_speeds[0] / 2;

        sysctl_node = NULL;

        if (sysctl_createv(NULL, 0, NULL, 
            &me, 
            CTLFLAG_READWRITE, CTLTYPE_NODE, "cpu", NULL, NULL,
            0, NULL, 0, CTL_MACHDEP, CTL_CREATE, CTL_EOL) != 0)
                printf("couldn't create 'cpu' node\n");
        
        if (sysctl_createv(NULL, 0, NULL, 
            &freq, 
            CTLFLAG_READWRITE, CTLTYPE_NODE, "frequency", NULL, NULL,
            0, NULL, 0, CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL) != 0)
                printf("couldn't create 'frequency' node\n");

        if (sysctl_createv(NULL, 0, NULL, 
            &sysctl_node, 
            CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
            CTLTYPE_INT, "target", "CPU speed", sysctl_cpuspeed_temp, 
            0, NULL, 0, CTL_MACHDEP, me->sysctl_num, freq->sysctl_num, 
            CTL_CREATE, CTL_EOL) == 0) {
        } else
                printf("couldn't create 'target' node\n");

        if (sysctl_createv(NULL, 0, NULL, 
            &sysctl_node, 
            CTLFLAG_READWRITE,
            CTLTYPE_INT, "current", NULL, sysctl_cpuspeed_cur, 
            1, NULL, 0, CTL_MACHDEP, me->sysctl_num, freq->sysctl_num, 
            CTL_CREATE, CTL_EOL) == 0) {
        } else
                printf("couldn't create 'current' node\n");

        if (sysctl_createv(NULL, 0, NULL, 
            &sysctl_node, 
            CTLFLAG_READWRITE,
            CTLTYPE_STRING, "available", NULL, sysctl_cpuspeed_available, 
            2, NULL, 0, CTL_MACHDEP, me->sysctl_num, freq->sysctl_num, 
            CTL_CREATE, CTL_EOL) == 0) {
        } else
                printf("couldn't create 'available' node\n");
}

static int
sysctl_cpuspeed_temp(SYSCTLFN_ARGS)
{
        struct sysctlnode node = *rnode;
        int speed, nspeed = -1, mhz;

        speed = (scom_read(SCOM_PSR) >> 56) & 3;
        if (speed > 1) speed = 1;
        mhz = scom_speeds[speed];
        node.sysctl_data = &mhz;

        if (sysctl_lookup(SYSCTLFN_CALL(&node)) == 0) {
                int new_reg;

                new_reg = *(int *)node.sysctl_data;
                if (new_reg == scom_speeds[0]) {
                        nspeed = 0;
                } else if (new_reg == scom_speeds[1]) {
                        nspeed = 1;
                } else {
                        printf("%s: new_reg %d\n", __func__, new_reg);
                        return EINVAL;
                }
                if (nspeed != speed) {
                        volatile uint64_t junk;
                        scom_write(SCOM_PCR, 0x80000000);
                        scom_write(SCOM_PCR, scom_reg[nspeed]);
                        junk = scom_read(SCOM_PSR);
                        __USE(junk);
                }
                return 0;
        }
        return EINVAL;
}

static int
sysctl_cpuspeed_cur(SYSCTLFN_ARGS)
{
        struct sysctlnode node = *rnode;
        uint64_t speed;
        int mhz;

        speed = (scom_read(SCOM_PSR) >> 56) & 3;
        if (speed > 1) speed = 1;

        mhz = scom_speeds[speed];
        node.sysctl_data = &mhz;
        return sysctl_lookup(SYSCTLFN_CALL(&node));
}

static int
sysctl_cpuspeed_available(SYSCTLFN_ARGS)
{
        struct sysctlnode node = *rnode;
        char buf[128];

        snprintf(buf, 128, "%d %d", scom_speeds[0], scom_speeds[1]);    
        node.sysctl_data = buf;
        return(sysctl_lookup(SYSCTLFN_CALL(&node)));
}

SYSCTL_SETUP(sysctl_ams_setup, "sysctl obio subtree setup")
{

        sysctl_createv(NULL, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "machdep", NULL,
                       NULL, 0, NULL, 0,
                       CTL_MACHDEP, CTL_EOL);
}