/*-
 * Copyright (c) 2003-2005 Nate Lawson (SDG)
 * 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>
#include "opt_acpi.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/power.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/sbuf.h>
#include <sys/pcpu.h>

#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/rman.h>

#include <contrib/dev/acpica/include/acpi.h>

#include <dev/acpica/acpivar.h>

#include "cpufreq_if.h"

/*
 * Support for ACPI processor performance states (Px) according to
 * section 8.3.3 of the ACPI 2.0c specification.
 */

struct acpi_px {
        uint32_t         core_freq;
        uint32_t         power;
        uint32_t         trans_lat;
        uint32_t         bm_lat;
        uint32_t         ctrl_val;
        uint32_t         sts_val;
};

/* Offsets in struct cf_setting array for storing driver-specific values. */
#define PX_SPEC_CONTROL 0
#define PX_SPEC_STATUS  1

#define MAX_PX_STATES   16

struct acpi_perf_softc {
        device_t         dev;
        ACPI_HANDLE      handle;
        struct resource *perf_ctrl;     /* Set new performance state. */
        int              perf_ctrl_type; /* Resource type for perf_ctrl. */
        struct resource *perf_status;   /* Check that transition succeeded. */
        int              perf_sts_type; /* Resource type for perf_status. */
        struct acpi_px  *px_states;     /* ACPI perf states. */
        uint32_t         px_count;      /* Total number of perf states. */
        uint32_t         px_max_avail;  /* Lowest index state available. */
        int              px_curr_state; /* Active state index. */
        int              px_rid;
        int              info_only;     /* Can we set new states? */
};

#define PX_GET_REG(reg)                                 \
        (bus_space_read_4(rman_get_bustag((reg)),       \
            rman_get_bushandle((reg)), 0))
#define PX_SET_REG(reg, val)                            \
        (bus_space_write_4(rman_get_bustag((reg)),      \
            rman_get_bushandle((reg)), 0, (val)))

#define ACPI_NOTIFY_PERF_STATES         0x80    /* _PSS changed. */

static void     acpi_perf_identify(driver_t *driver, device_t parent);
static int      acpi_perf_probe(device_t dev);
static int      acpi_perf_attach(device_t dev);
static int      acpi_perf_detach(device_t dev);
static int      acpi_perf_evaluate(device_t dev);
static int      acpi_px_to_set(device_t dev, struct acpi_px *px,
                    struct cf_setting *set);
static void     acpi_px_available(struct acpi_perf_softc *sc);
static void     acpi_px_startup(void *arg);
static void     acpi_px_notify(ACPI_HANDLE h, UINT32 notify, void *context);
static int      acpi_px_settings(device_t dev, struct cf_setting *sets,
                    int *count);
static int      acpi_px_set(device_t dev, const struct cf_setting *set);
static int      acpi_px_get(device_t dev, struct cf_setting *set);
static int      acpi_px_type(device_t dev, int *type);

static device_method_t acpi_perf_methods[] = {
        /* Device interface */
        DEVMETHOD(device_identify,      acpi_perf_identify),
        DEVMETHOD(device_probe,         acpi_perf_probe),
        DEVMETHOD(device_attach,        acpi_perf_attach),
        DEVMETHOD(device_detach,        acpi_perf_detach),

        /* cpufreq interface */
        DEVMETHOD(cpufreq_drv_set,      acpi_px_set),
        DEVMETHOD(cpufreq_drv_get,      acpi_px_get),
        DEVMETHOD(cpufreq_drv_type,     acpi_px_type),
        DEVMETHOD(cpufreq_drv_settings, acpi_px_settings),

        DEVMETHOD_END
};

static driver_t acpi_perf_driver = {
        "acpi_perf",
        acpi_perf_methods,
        sizeof(struct acpi_perf_softc),
};

DRIVER_MODULE(acpi_perf, cpu, acpi_perf_driver, 0, 0);
MODULE_DEPEND(acpi_perf, acpi, 1, 1, 1);

static MALLOC_DEFINE(M_ACPIPERF, "acpi_perf", "ACPI Performance states");

static void
acpi_perf_identify(driver_t *driver, device_t parent)
{
        ACPI_HANDLE handle;
        device_t dev;

        /* Make sure we're not being doubly invoked. */
        if (device_find_child(parent, "acpi_perf", DEVICE_UNIT_ANY) != NULL)
                return;

        /* Get the handle for the Processor object and check for perf states. */
        handle = acpi_get_handle(parent);
        if (handle == NULL)
                return;
        if (ACPI_FAILURE(AcpiEvaluateObject(handle, "_PSS", NULL, NULL)))
                return;

        /*
         * Add a child to every CPU that has the right methods.  In future
         * versions of the ACPI spec, CPUs can have different settings.
         * We probe this child now so that other devices that depend
         * on it (i.e., for info about supported states) will see it.
         */
        if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_perf",
            device_get_unit(parent))) != NULL)
                device_probe_and_attach(dev);
        else
                device_printf(parent, "add acpi_perf child failed\n");
}

static int
acpi_perf_probe(device_t dev)
{
        ACPI_HANDLE handle;
        ACPI_OBJECT *pkg;
        struct resource *res;
        ACPI_BUFFER buf;
        int error, rid, type;

        if (resource_disabled("acpi_perf", 0))
                return (ENXIO);

        /*
         * Check the performance state registers.  If they are of type
         * "functional fixed hardware", we attach quietly since we will
         * only be providing information on settings to other drivers.
         */
        error = ENXIO;
        handle = acpi_get_handle(dev);
        buf.Pointer = NULL;
        buf.Length = ACPI_ALLOCATE_BUFFER;
        if (ACPI_FAILURE(AcpiEvaluateObject(handle, "_PCT", NULL, &buf)))
                return (error);
        pkg = (ACPI_OBJECT *)buf.Pointer;
        if (ACPI_PKG_VALID(pkg, 2)) {
                rid = 0;
                error = acpi_PkgGas(dev, pkg, 0, &type, rid, &res, 0);
                switch (error) {
                case 0:
                        bus_release_resource(dev, type, rid, res);
                        bus_delete_resource(dev, type, rid);
                        device_set_desc(dev, "ACPI CPU Frequency Control");
                        break;
                case EOPNOTSUPP:
                        device_quiet(dev);
                        error = 0;
                        break;
                }
        }
        AcpiOsFree(buf.Pointer);

        return (error);
}

static int
acpi_perf_attach(device_t dev)
{
        struct acpi_perf_softc *sc;

        sc = device_get_softc(dev);
        sc->dev = dev;
        sc->handle = acpi_get_handle(dev);
        sc->px_max_avail = 0;
        sc->px_curr_state = CPUFREQ_VAL_UNKNOWN;
        if (acpi_perf_evaluate(dev) != 0)
                return (ENXIO);
        AcpiOsExecute(OSL_NOTIFY_HANDLER, acpi_px_startup, NULL);
        if (!sc->info_only)
                cpufreq_register(dev);

        return (0);
}

static int
acpi_perf_detach(device_t dev)
{
        /* TODO: teardown registers, remove notify handler. */
        return (ENXIO);
}

/* Probe and setup any valid performance states (Px). */
static int
acpi_perf_evaluate(device_t dev)
{
        struct acpi_perf_softc *sc;
        ACPI_BUFFER buf;
        ACPI_OBJECT *pkg, *res;
        ACPI_STATUS status;
        int count, error, i, j;
        static int once = 1;
        uint32_t *p;

        /* Get the control values and parameters for each state. */
        error = ENXIO;
        sc = device_get_softc(dev);
        buf.Pointer = NULL;
        buf.Length = ACPI_ALLOCATE_BUFFER;
        status = AcpiEvaluateObject(sc->handle, "_PSS", NULL, &buf);
        if (ACPI_FAILURE(status))
                return (ENXIO);

        pkg = (ACPI_OBJECT *)buf.Pointer;
        if (!ACPI_PKG_VALID(pkg, 1)) {
                device_printf(dev, "invalid top level _PSS package\n");
                goto out;
        }
        sc->px_count = pkg->Package.Count;

        sc->px_states = malloc(sc->px_count * sizeof(struct acpi_px),
            M_ACPIPERF, M_WAITOK | M_ZERO);

        /*
         * Each state is a package of {CoreFreq, Power, TransitionLatency,
         * BusMasterLatency, ControlVal, StatusVal}, sorted from highest
         * performance to lowest.
         */
        count = 0;
        for (i = 0; i < sc->px_count; i++) {
                res = &pkg->Package.Elements[i];
                if (!ACPI_PKG_VALID(res, 6)) {
                        if (once) {
                                once = 0;
                                device_printf(dev, "invalid _PSS package\n");
                        }
                        continue;
                }

                /* Parse the rest of the package into the struct. */
                p = &sc->px_states[count].core_freq;
                for (j = 0; j < 6; j++, p++)
                        acpi_PkgInt32(res, j, p);

                /*
                 * Check for some impossible frequencies that some systems
                 * use to indicate they don't actually support this Px state.
                 */
                if (sc->px_states[count].core_freq == 0 ||
                    sc->px_states[count].core_freq == 9999 ||
                    sc->px_states[count].core_freq == 0x9999 ||
                    sc->px_states[count].core_freq >= 0xffff)
                        continue;

                /* Check for duplicate entries */
                if (count > 0 &&
                    sc->px_states[count - 1].core_freq ==
                        sc->px_states[count].core_freq)
                        continue;

                count++;
        }
        sc->px_count = count;

        /* No valid Px state found so give up. */
        if (count == 0)
                goto out;
        AcpiOsFree(buf.Pointer);

        /* Get the control and status registers (one of each). */
        buf.Pointer = NULL;
        buf.Length = ACPI_ALLOCATE_BUFFER;
        status = AcpiEvaluateObject(sc->handle, "_PCT", NULL, &buf);
        if (ACPI_FAILURE(status))
                goto out;

        /* Check the package of two registers, each a Buffer in GAS format. */
        pkg = (ACPI_OBJECT *)buf.Pointer;
        if (!ACPI_PKG_VALID(pkg, 2)) {
                device_printf(dev, "invalid perf register package\n");
                goto out;
        }

        error = acpi_PkgGas(sc->dev, pkg, 0, &sc->perf_ctrl_type, sc->px_rid,
            &sc->perf_ctrl, 0);
        if (error) {
                /*
                 * If the register is of type FFixedHW, we can only return
                 * info, we can't get or set new settings.
                 */
                if (error == EOPNOTSUPP) {
                        sc->info_only = TRUE;
                        error = 0;
                } else
                        device_printf(dev, "failed in PERF_CTL attach\n");
                goto out;
        }
        sc->px_rid++;

        error = acpi_PkgGas(sc->dev, pkg, 1, &sc->perf_sts_type, sc->px_rid,
            &sc->perf_status, 0);
        if (error) {
                if (error == EOPNOTSUPP) {
                        sc->info_only = TRUE;
                        error = 0;
                } else
                        device_printf(dev, "failed in PERF_STATUS attach\n");
                goto out;
        }
        sc->px_rid++;

        /* Get our current limit and register for notifies. */
        acpi_px_available(sc);
        AcpiInstallNotifyHandler(sc->handle, ACPI_DEVICE_NOTIFY,
            acpi_px_notify, sc);
        error = 0;

out:
        if (error) {
                if (sc->px_states) {
                        free(sc->px_states, M_ACPIPERF);
                        sc->px_states = NULL;
                }
                if (sc->perf_ctrl) {
                        bus_release_resource(sc->dev, sc->perf_ctrl_type, 0,
                            sc->perf_ctrl);
                        bus_delete_resource(sc->dev, sc->perf_ctrl_type, 0);
                        sc->perf_ctrl = NULL;
                }
                if (sc->perf_status) {
                        bus_release_resource(sc->dev, sc->perf_sts_type, 1,
                            sc->perf_status);
                        bus_delete_resource(sc->dev, sc->perf_sts_type, 1);
                        sc->perf_status = NULL;
                }
                sc->px_rid = 0;
                sc->px_count = 0;
        }
        if (buf.Pointer)
                AcpiOsFree(buf.Pointer);
        return (error);
}

static void
acpi_px_startup(void *arg)
{

        /* Signal to the platform that we are taking over CPU control. */
        if (AcpiGbl_FADT.PstateControl == 0)
                return;
        ACPI_LOCK(acpi);
        AcpiOsWritePort(AcpiGbl_FADT.SmiCommand, AcpiGbl_FADT.PstateControl, 8);
        ACPI_UNLOCK(acpi);
}

static void
acpi_px_notify(ACPI_HANDLE h, UINT32 notify, void *context)
{
        struct acpi_perf_softc *sc;

        sc = context;
        if (notify != ACPI_NOTIFY_PERF_STATES)
                return;

        acpi_px_available(sc);

        /* TODO: Implement notification when frequency changes. */
}

/*
 * Find the highest currently-supported performance state.
 * This can be called at runtime (e.g., due to a docking event) at
 * the request of a Notify on the processor object.
 */
static void
acpi_px_available(struct acpi_perf_softc *sc)
{
        ACPI_STATUS status;
        struct cf_setting set;

        status = acpi_GetInteger(sc->handle, "_PPC", &sc->px_max_avail);

        /* If the old state is too high, set current state to the new max. */
        if (ACPI_SUCCESS(status)) {
                if (sc->px_curr_state != CPUFREQ_VAL_UNKNOWN &&
                    sc->px_curr_state > sc->px_max_avail) {
                        acpi_px_to_set(sc->dev,
                            &sc->px_states[sc->px_max_avail], &set);
                        acpi_px_set(sc->dev, &set);
                }
        } else
                sc->px_max_avail = 0;
}

static int
acpi_px_to_set(device_t dev, struct acpi_px *px, struct cf_setting *set)
{

        if (px == NULL || set == NULL)
                return (EINVAL);

        set->freq = px->core_freq;
        set->power = px->power;
        /* XXX Include BM latency too? */
        set->lat = px->trans_lat;
        set->volts = CPUFREQ_VAL_UNKNOWN;
        set->dev = dev;
        set->spec[PX_SPEC_CONTROL] = px->ctrl_val;
        set->spec[PX_SPEC_STATUS] = px->sts_val;

        return (0);
}

static int
acpi_px_settings(device_t dev, struct cf_setting *sets, int *count)
{
        struct acpi_perf_softc *sc;
        int x, y;

        sc = device_get_softc(dev);
        if (sets == NULL || count == NULL)
                return (EINVAL);
        if (*count < sc->px_count - sc->px_max_avail)
                return (E2BIG);

        /* Return a list of settings that are currently valid. */
        y = 0;
        for (x = sc->px_max_avail; x < sc->px_count; x++, y++)
                acpi_px_to_set(dev, &sc->px_states[x], &sets[y]);
        *count = sc->px_count - sc->px_max_avail;

        return (0);
}

static int
acpi_px_set(device_t dev, const struct cf_setting *set)
{
        struct acpi_perf_softc *sc;
        int i, status, sts_val, tries;

        if (set == NULL)
                return (EINVAL);
        sc = device_get_softc(dev);

        /* If we can't set new states, return immediately. */
        if (sc->info_only)
                return (ENXIO);

        /* Look up appropriate state, based on frequency. */
        for (i = sc->px_max_avail; i < sc->px_count; i++) {
                if (CPUFREQ_CMP(set->freq, sc->px_states[i].core_freq))
                        break;
        }
        if (i == sc->px_count)
                return (EINVAL);

        /* Write the appropriate value to the register. */
        PX_SET_REG(sc->perf_ctrl, sc->px_states[i].ctrl_val);

        /*
         * Try for up to 10 ms to verify the desired state was selected.
         * This is longer than the standard says (1 ms) but in some modes,
         * systems may take longer to respond.
         */
        sts_val = sc->px_states[i].sts_val;
        for (tries = 0; tries < 1000; tries++) {
                status = PX_GET_REG(sc->perf_status);

                /*
                 * If we match the status or the desired status is 8 bits
                 * and matches the relevant bits, assume we succeeded.  It
                 * appears some systems (IBM R32) expect byte-wide access
                 * even though the standard says the register is 32-bit.
                 */
                if (status == sts_val ||
                    ((sts_val & ~0xff) == 0 && (status & 0xff) == sts_val))
                        break;
                DELAY(10);
        }
        if (tries == 1000) {
                device_printf(dev, "Px transition to %d failed\n",
                    sc->px_states[i].core_freq);
                return (ENXIO);
        }
        sc->px_curr_state = i;

        return (0);
}

static int
acpi_px_get(device_t dev, struct cf_setting *set)
{
        struct acpi_perf_softc *sc;
        uint64_t rate;
        int i;
        struct pcpu *pc;

        if (set == NULL)
                return (EINVAL);
        sc = device_get_softc(dev);

        /* If we can't get new states, return immediately. */
        if (sc->info_only)
                return (ENXIO);

        /* If we've set the rate before, use the cached value. */
        if (sc->px_curr_state != CPUFREQ_VAL_UNKNOWN) {
                acpi_px_to_set(dev, &sc->px_states[sc->px_curr_state], set);
                return (0);
        }

        /* Otherwise, estimate and try to match against our settings. */
        pc = cpu_get_pcpu(dev);
        if (pc == NULL)
                return (ENXIO);
        cpu_est_clockrate(pc->pc_cpuid, &rate);
        rate /= 1000000;
        for (i = 0; i < sc->px_count; i++) {
                if (CPUFREQ_CMP(sc->px_states[i].core_freq, rate)) {
                        sc->px_curr_state = i;
                        acpi_px_to_set(dev, &sc->px_states[i], set);
                        break;
                }
        }

        /* No match, give up. */
        if (i == sc->px_count) {
                sc->px_curr_state = CPUFREQ_VAL_UNKNOWN;
                set->freq = CPUFREQ_VAL_UNKNOWN;
        }

        return (0);
}

static int
acpi_px_type(device_t dev, int *type)
{
        struct acpi_perf_softc *sc;

        if (type == NULL)
                return (EINVAL);
        sc = device_get_softc(dev);

        *type = CPUFREQ_TYPE_ABSOLUTE;
        if (sc->info_only)
                *type |= CPUFREQ_FLAG_INFO_ONLY;
        return (0);
}