// SPDX-License-Identifier: GPL-2.0-only
/*
 * Windfarm PowerMac thermal control. SMU based sensors
 *
 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 *                    <benh@kernel.crashing.org>
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/completion.h>
#include <linux/of.h>

#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/sections.h>
#include <asm/smu.h>

#include "windfarm.h"

#define VERSION "0.2"

#undef DEBUG

#ifdef DEBUG
#define DBG(args...)    printk(args)
#else
#define DBG(args...)    do { } while(0)
#endif

/*
 * Various SMU "partitions" calibration objects for which we
 * keep pointers here for use by bits & pieces of the driver
 */
static struct smu_sdbp_cpuvcp *cpuvcp;
static int  cpuvcp_version;
static struct smu_sdbp_cpudiode *cpudiode;
static struct smu_sdbp_slotspow *slotspow;
static u8 *debugswitches;

/*
 * SMU basic sensors objects
 */

static LIST_HEAD(smu_ads);

struct smu_ad_sensor {
        struct list_head        link;
        u32                     reg;            /* index in SMU */
        struct wf_sensor        sens;
};
#define to_smu_ads(c) container_of(c, struct smu_ad_sensor, sens)

static void smu_ads_release(struct wf_sensor *sr)
{
        struct smu_ad_sensor *ads = to_smu_ads(sr);

        kfree(ads);
}

static int smu_read_adc(u8 id, s32 *value)
{
        struct smu_simple_cmd   cmd;
        DECLARE_COMPLETION_ONSTACK(comp);
        int rc;

        rc = smu_queue_simple(&cmd, SMU_CMD_READ_ADC, 1,
                              smu_done_complete, &comp, id);
        if (rc)
                return rc;
        wait_for_completion(&comp);
        if (cmd.cmd.status != 0)
                return cmd.cmd.status;
        if (cmd.cmd.reply_len != 2) {
                printk(KERN_ERR "winfarm: read ADC 0x%x returned %d bytes !\n",
                       id, cmd.cmd.reply_len);
                return -EIO;
        }
        *value = *((u16 *)cmd.buffer);
        return 0;
}

static int smu_cputemp_get(struct wf_sensor *sr, s32 *value)
{
        struct smu_ad_sensor *ads = to_smu_ads(sr);
        int rc;
        s32 val;
        s64 scaled;

        rc = smu_read_adc(ads->reg, &val);
        if (rc) {
                printk(KERN_ERR "windfarm: read CPU temp failed, err %d\n",
                       rc);
                return rc;
        }

        /* Ok, we have to scale & adjust, taking units into account */
        scaled = (s64)(((u64)val) * (u64)cpudiode->m_value);
        scaled >>= 3;
        scaled += ((s64)cpudiode->b_value) << 9;
        *value = (s32)(scaled << 1);

        return 0;
}

static int smu_cpuamp_get(struct wf_sensor *sr, s32 *value)
{
        struct smu_ad_sensor *ads = to_smu_ads(sr);
        s32 val, scaled;
        int rc;

        rc = smu_read_adc(ads->reg, &val);
        if (rc) {
                printk(KERN_ERR "windfarm: read CPU current failed, err %d\n",
                       rc);
                return rc;
        }

        /* Ok, we have to scale & adjust, taking units into account */
        scaled = (s32)(val * (u32)cpuvcp->curr_scale);
        scaled += (s32)cpuvcp->curr_offset;
        *value = scaled << 4;

        return 0;
}

static int smu_cpuvolt_get(struct wf_sensor *sr, s32 *value)
{
        struct smu_ad_sensor *ads = to_smu_ads(sr);
        s32 val, scaled;
        int rc;

        rc = smu_read_adc(ads->reg, &val);
        if (rc) {
                printk(KERN_ERR "windfarm: read CPU voltage failed, err %d\n",
                       rc);
                return rc;
        }

        /* Ok, we have to scale & adjust, taking units into account */
        scaled = (s32)(val * (u32)cpuvcp->volt_scale);
        scaled += (s32)cpuvcp->volt_offset;
        *value = scaled << 4;

        return 0;
}

static int smu_slotspow_get(struct wf_sensor *sr, s32 *value)
{
        struct smu_ad_sensor *ads = to_smu_ads(sr);
        s32 val, scaled;
        int rc;

        rc = smu_read_adc(ads->reg, &val);
        if (rc) {
                printk(KERN_ERR "windfarm: read slots power failed, err %d\n",
                       rc);
                return rc;
        }

        /* Ok, we have to scale & adjust, taking units into account */
        scaled = (s32)(val * (u32)slotspow->pow_scale);
        scaled += (s32)slotspow->pow_offset;
        *value = scaled << 4;

        return 0;
}


static const struct wf_sensor_ops smu_cputemp_ops = {
        .get_value      = smu_cputemp_get,
        .release        = smu_ads_release,
        .owner          = THIS_MODULE,
};
static const struct wf_sensor_ops smu_cpuamp_ops = {
        .get_value      = smu_cpuamp_get,
        .release        = smu_ads_release,
        .owner          = THIS_MODULE,
};
static const struct wf_sensor_ops smu_cpuvolt_ops = {
        .get_value      = smu_cpuvolt_get,
        .release        = smu_ads_release,
        .owner          = THIS_MODULE,
};
static const struct wf_sensor_ops smu_slotspow_ops = {
        .get_value      = smu_slotspow_get,
        .release        = smu_ads_release,
        .owner          = THIS_MODULE,
};


static struct smu_ad_sensor *smu_ads_create(struct device_node *node)
{
        struct smu_ad_sensor *ads;
        const char *l;
        const u32 *v;

        ads = kmalloc_obj(struct smu_ad_sensor);
        if (ads == NULL)
                return NULL;
        l = of_get_property(node, "location", NULL);
        if (l == NULL)
                goto fail;

        /* We currently pick the sensors based on the OF name and location
         * properties, while Darwin uses the sensor-id's.
         * The problem with the IDs is that they are model specific while it
         * looks like apple has been doing a reasonably good job at keeping
         * the names and locations consistents so I'll stick with the names
         * and locations for now.
         */
        if (of_node_is_type(node, "temp-sensor") &&
            !strcmp(l, "CPU T-Diode")) {
                ads->sens.ops = &smu_cputemp_ops;
                ads->sens.name = "cpu-temp";
                if (cpudiode == NULL) {
                        DBG("wf: cpudiode partition (%02x) not found\n",
                            SMU_SDB_CPUDIODE_ID);
                        goto fail;
                }
        } else if (of_node_is_type(node, "current-sensor") &&
                   !strcmp(l, "CPU Current")) {
                ads->sens.ops = &smu_cpuamp_ops;
                ads->sens.name = "cpu-current";
                if (cpuvcp == NULL) {
                        DBG("wf: cpuvcp partition (%02x) not found\n",
                            SMU_SDB_CPUVCP_ID);
                        goto fail;
                }
        } else if (of_node_is_type(node, "voltage-sensor") &&
                   !strcmp(l, "CPU Voltage")) {
                ads->sens.ops = &smu_cpuvolt_ops;
                ads->sens.name = "cpu-voltage";
                if (cpuvcp == NULL) {
                        DBG("wf: cpuvcp partition (%02x) not found\n",
                            SMU_SDB_CPUVCP_ID);
                        goto fail;
                }
        } else if (of_node_is_type(node, "power-sensor") &&
                   !strcmp(l, "Slots Power")) {
                ads->sens.ops = &smu_slotspow_ops;
                ads->sens.name = "slots-power";
                if (slotspow == NULL) {
                        DBG("wf: slotspow partition (%02x) not found\n",
                            SMU_SDB_SLOTSPOW_ID);
                        goto fail;
                }
        } else
                goto fail;

        v = of_get_property(node, "reg", NULL);
        if (v == NULL)
                goto fail;
        ads->reg = *v;

        if (wf_register_sensor(&ads->sens))
                goto fail;
        return ads;
 fail:
        kfree(ads);
        return NULL;
}

/*
 * SMU Power combo sensor object
 */

struct smu_cpu_power_sensor {
        struct list_head        link;
        struct wf_sensor        *volts;
        struct wf_sensor        *amps;
        unsigned int            fake_volts : 1;
        unsigned int            quadratic : 1;
        struct wf_sensor        sens;
};
#define to_smu_cpu_power(c) container_of(c, struct smu_cpu_power_sensor, sens)

static struct smu_cpu_power_sensor *smu_cpu_power;

static void smu_cpu_power_release(struct wf_sensor *sr)
{
        struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);

        if (pow->volts)
                wf_put_sensor(pow->volts);
        if (pow->amps)
                wf_put_sensor(pow->amps);
        kfree(pow);
}

static int smu_cpu_power_get(struct wf_sensor *sr, s32 *value)
{
        struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);
        s32 volts, amps, power;
        u64 tmps, tmpa, tmpb;
        int rc;

        rc = pow->amps->ops->get_value(pow->amps, &amps);
        if (rc)
                return rc;

        if (pow->fake_volts) {
                *value = amps * 12 - 0x30000;
                return 0;
        }

        rc = pow->volts->ops->get_value(pow->volts, &volts);
        if (rc)
                return rc;

        power = (s32)((((u64)volts) * ((u64)amps)) >> 16);
        if (!pow->quadratic) {
                *value = power;
                return 0;
        }
        tmps = (((u64)power) * ((u64)power)) >> 16;
        tmpa = ((u64)cpuvcp->power_quads[0]) * tmps;
        tmpb = ((u64)cpuvcp->power_quads[1]) * ((u64)power);
        *value = (tmpa >> 28) + (tmpb >> 28) + (cpuvcp->power_quads[2] >> 12);

        return 0;
}

static const struct wf_sensor_ops smu_cpu_power_ops = {
        .get_value      = smu_cpu_power_get,
        .release        = smu_cpu_power_release,
        .owner          = THIS_MODULE,
};


static struct smu_cpu_power_sensor *
smu_cpu_power_create(struct wf_sensor *volts, struct wf_sensor *amps)
{
        struct smu_cpu_power_sensor *pow;

        pow = kmalloc_obj(struct smu_cpu_power_sensor);
        if (pow == NULL)
                return NULL;
        pow->sens.ops = &smu_cpu_power_ops;
        pow->sens.name = "cpu-power";

        wf_get_sensor(volts);
        pow->volts = volts;
        wf_get_sensor(amps);
        pow->amps = amps;

        /* Some early machines need a faked voltage */
        if (debugswitches && ((*debugswitches) & 0x80)) {
                printk(KERN_INFO "windfarm: CPU Power sensor using faked"
                       " voltage !\n");
                pow->fake_volts = 1;
        } else
                pow->fake_volts = 0;

        /* Try to use quadratic transforms on PowerMac8,1 and 9,1 for now,
         * I yet have to figure out what's up with 8,2 and will have to
         * adjust for later, unless we can 100% trust the SDB partition...
         */
        if ((of_machine_is_compatible("PowerMac8,1") ||
             of_machine_is_compatible("PowerMac8,2") ||
             of_machine_is_compatible("PowerMac9,1")) &&
            cpuvcp_version >= 2) {
                pow->quadratic = 1;
                DBG("windfarm: CPU Power using quadratic transform\n");
        } else
                pow->quadratic = 0;

        if (wf_register_sensor(&pow->sens))
                goto fail;
        return pow;
 fail:
        kfree(pow);
        return NULL;
}

static void smu_fetch_param_partitions(void)
{
        const struct smu_sdbp_header *hdr;

        /* Get CPU voltage/current/power calibration data */
        hdr = smu_get_sdb_partition(SMU_SDB_CPUVCP_ID, NULL);
        if (hdr != NULL) {
                cpuvcp = (struct smu_sdbp_cpuvcp *)&hdr[1];
                /* Keep version around */
                cpuvcp_version = hdr->version;
        }

        /* Get CPU diode calibration data */
        hdr = smu_get_sdb_partition(SMU_SDB_CPUDIODE_ID, NULL);
        if (hdr != NULL)
                cpudiode = (struct smu_sdbp_cpudiode *)&hdr[1];

        /* Get slots power calibration data if any */
        hdr = smu_get_sdb_partition(SMU_SDB_SLOTSPOW_ID, NULL);
        if (hdr != NULL)
                slotspow = (struct smu_sdbp_slotspow *)&hdr[1];

        /* Get debug switches if any */
        hdr = smu_get_sdb_partition(SMU_SDB_DEBUG_SWITCHES_ID, NULL);
        if (hdr != NULL)
                debugswitches = (u8 *)&hdr[1];
}

static int __init smu_sensors_init(void)
{
        struct device_node *smu, *sensors, *s;
        struct smu_ad_sensor *volt_sensor = NULL, *curr_sensor = NULL;

        if (!smu_present())
                return -ENODEV;

        /* Get parameters partitions */
        smu_fetch_param_partitions();

        smu = of_find_node_by_type(NULL, "smu");
        if (smu == NULL)
                return -ENODEV;

        /* Look for sensors subdir */
        for_each_child_of_node(smu, sensors)
                if (of_node_name_eq(sensors, "sensors"))
                        break;

        of_node_put(smu);

        /* Create basic sensors */
        for (s = NULL;
             sensors && (s = of_get_next_child(sensors, s)) != NULL;) {
                struct smu_ad_sensor *ads;

                ads = smu_ads_create(s);
                if (ads == NULL)
                        continue;
                list_add(&ads->link, &smu_ads);
                /* keep track of cpu voltage & current */
                if (!strcmp(ads->sens.name, "cpu-voltage"))
                        volt_sensor = ads;
                else if (!strcmp(ads->sens.name, "cpu-current"))
                        curr_sensor = ads;
        }

        of_node_put(sensors);

        /* Create CPU power sensor if possible */
        if (volt_sensor && curr_sensor)
                smu_cpu_power = smu_cpu_power_create(&volt_sensor->sens,
                                                     &curr_sensor->sens);

        return 0;
}

static void __exit smu_sensors_exit(void)
{
        struct smu_ad_sensor *ads;

        /* dispose of power sensor */
        if (smu_cpu_power)
                wf_unregister_sensor(&smu_cpu_power->sens);

        /* dispose of basic sensors */
        while (!list_empty(&smu_ads)) {
                ads = list_entry(smu_ads.next, struct smu_ad_sensor, link);
                list_del(&ads->link);
                wf_unregister_sensor(&ads->sens);
        }
}


module_init(smu_sensors_init);
module_exit(smu_sensors_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("SMU sensor objects for PowerMacs thermal control");
MODULE_LICENSE("GPL");