// SPDX-License-Identifier: GPL-2.0+
/*
 * Texas Instruments' K3 Clas 0 Adaptive Voltage Scaling driver
 *
 * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
 *      Tero Kristo <t-kristo@ti.com>
 *
 */

#include <common.h>
#include <dm.h>
#include <errno.h>
#include <asm/io.h>
#include <i2c.h>
#include <k3-avs.h>
#include <dm/device_compat.h>
#include <linux/bitops.h>
#include <power/regulator.h>

#define AM6_VTM_DEVINFO(i)      (priv->base + 0x100 + 0x20 * (i))
#define AM6_VTM_OPPVID_VD(i)    (priv->base + 0x104 + 0x20 * (i))

#define AM6_VTM_AVS0_SUPPORTED  BIT(12)

#define AM6_VTM_OPP_SHIFT(opp)  (8 * (opp))
#define AM6_VTM_OPP_MASK        0xff

#define VD_FLAG_INIT_DONE       BIT(0)

struct k3_avs_privdata {
        void *base;
        struct vd_config *vd_config;
};

struct opp {
        u32 freq;
        u32 volt;
};

struct vd_data {
        int id;
        u8 opp;
        u8 flags;
        int dev_id;
        int clk_id;
        struct opp opps[NUM_OPPS];
        struct udevice *supply;
};

struct vd_config {
        struct vd_data *vds;
        u32 (*efuse_xlate)(struct k3_avs_privdata *priv, int idx, int opp);
};

static struct k3_avs_privdata *k3_avs_priv;

/**
 * am6_efuse_voltage: read efuse voltage from VTM
 * @priv: driver private data
 * @idx: VD to read efuse for
 * @opp: opp id to read
 *
 * Reads efuse value for the specified OPP, and converts the register
 * value to a voltage. Returns the voltage in uV, or 0 if nominal voltage
 * should be used.
 *
 * Efuse val to volt conversion logic:
 *
 * val > 171 volt increments in 20mV steps with base 171 => 1.66V
 * val between 115 to 11 increments in 10mV steps with base 115 => 1.1V
 * val between 15 to 115 increments in 5mV steps with base 15 => .6V
 * val between 1 to 15 increments in 20mv steps with base 0 => .3V
 * val 0 is invalid
 */
static u32 am6_efuse_xlate(struct k3_avs_privdata *priv, int idx, int opp)
{
        u32 val = readl(AM6_VTM_OPPVID_VD(idx));

        val >>= AM6_VTM_OPP_SHIFT(opp);
        val &= AM6_VTM_OPP_MASK;

        if (!val)
                return 0;

        if (val > 171)
                return 1660000 + 20000 * (val - 171);

        if (val > 115)
                return 1100000 + 10000 * (val - 115);

        if (val > 15)
                return 600000 + 5000 * (val - 15);

        return 300000 + 20000 * val;
}

static int k3_avs_program_voltage(struct k3_avs_privdata *priv,
                                  struct vd_data *vd,
                                  int opp_id)
{
        u32 volt = vd->opps[opp_id].volt;
        struct vd_data *vd2;

        if (!vd->supply)
                return -ENODEV;

        vd->opp = opp_id;
        vd->flags |= VD_FLAG_INIT_DONE;

        /* Take care of ganged rails and pick the Max amongst them*/
        for (vd2 = priv->vd_config->vds; vd2->id >= 0; vd2++) {
                if (vd == vd2)
                        continue;

                if (vd2->supply != vd->supply)
                        continue;

                if (vd2->opps[vd2->opp].volt > volt)
                        volt = vd2->opps[vd2->opp].volt;

                vd2->flags |= VD_FLAG_INIT_DONE;
        }

        return regulator_set_value(vd->supply, volt);
}

static struct vd_data *get_vd(struct k3_avs_privdata *priv, int idx)
{
        struct vd_data *vd;

        for (vd = priv->vd_config->vds; vd->id >= 0 && vd->id != idx; vd++)
                ;

        if (vd->id < 0)
                return NULL;

        return vd;
}

/**
 * k3_avs_set_opp: Sets the voltage for an arbitrary VD rail
 * @dev: AVS device
 * @vdd_id: voltage domain ID
 * @opp_id: OPP ID
 *
 * Programs the desired OPP value for the defined voltage rail. This
 * should be called from board files if reconfiguration is desired.
 * Returns 0 on success, negative error value on failure.
 */
int k3_avs_set_opp(struct udevice *dev, int vdd_id, int opp_id)
{
        struct k3_avs_privdata *priv = dev_get_priv(dev);
        struct vd_data *vd;

        vd = get_vd(priv, vdd_id);
        if (!vd)
                return -EINVAL;

        return k3_avs_program_voltage(priv, vd, opp_id);
}

static int match_opp(struct vd_data *vd, u32 freq)
{
        struct opp *opp;
        int opp_id;

        for (opp_id = 0; opp_id < NUM_OPPS; opp_id++) {
                opp = &vd->opps[opp_id];
                if (opp->freq == freq)
                        return opp_id;
        }

        printf("No matching OPP found for freq %d.\n", freq);

        return -EINVAL;
}

/**
 * k3_avs_notify_freq: Notify clock rate change towards AVS subsystem
 * @dev_id: Device ID for the clock to be changed
 * @clk_id: Clock ID for the clock to be changed
 * @freq: New frequency for clock
 *
 * Checks if the provided clock is the MPU clock or not, if not, return
 * immediately. If MPU clock is provided, maps the provided MPU frequency
 * towards an MPU OPP, and programs the voltage to the regulator. Return 0
 * on success, negative error value on failure.
 */
int k3_avs_notify_freq(int dev_id, int clk_id, u32 freq)
{
        int opp_id;
        struct k3_avs_privdata *priv = k3_avs_priv;
        struct vd_data *vd;

        /* Driver may not be probed yet */
        if (!priv)
                return -EINVAL;

        for (vd = priv->vd_config->vds; vd->id >= 0; vd++) {
                if (vd->dev_id != dev_id || vd->clk_id != clk_id)
                        continue;

                opp_id = match_opp(vd, freq);
                if (opp_id < 0)
                        return opp_id;

                vd->opp = opp_id;
                return k3_avs_program_voltage(priv, vd, opp_id);
        }

        return -EINVAL;
}

static int k3_avs_configure(struct udevice *dev, struct k3_avs_privdata *priv)
{
        struct vd_config *conf;
        int ret;
        char pname[20];
        struct vd_data *vd;

        conf = (void *)dev_get_driver_data(dev);

        priv->vd_config = conf;

        for (vd = conf->vds; vd->id >= 0; vd++) {
                sprintf(pname, "vdd-supply-%d", vd->id);
                ret = device_get_supply_regulator(dev, pname, &vd->supply);
                if (ret)
                        dev_warn(dev, "supply not found for VD%d.\n", vd->id);

                sprintf(pname, "ti,default-opp-%d", vd->id);
                ret = dev_read_u32_default(dev, pname, -1);
                if (ret != -1)
                        vd->opp = ret;
        }

        return 0;
}

/**
 * k3_avs_probe: parses VD info from VTM, and re-configures the OPP data
 *
 * Parses all VDs on a device calculating the AVS class-0 voltages for them,
 * and updates the vd_data based on this. The vd_data itself shall be used
 * to program the required OPPs later on. Returns 0 on success, negative
 * error value on failure.
 */
static int k3_avs_probe(struct udevice *dev)
{
        int opp_id;
        u32 volt;
        struct opp *opp;
        struct k3_avs_privdata *priv;
        struct vd_data *vd;
        int ret;

        priv = dev_get_priv(dev);

        k3_avs_priv = priv;

        ret = k3_avs_configure(dev, priv);
        if (ret)
                return ret;

        priv->base = dev_read_addr_ptr(dev);
        if (!priv->base)
                return -ENODEV;

        for (vd = priv->vd_config->vds; vd->id >= 0; vd++) {
                if (!(readl(AM6_VTM_DEVINFO(vd->id)) &
                      AM6_VTM_AVS0_SUPPORTED)) {
                        dev_warn(dev, "AVS-class 0 not supported for VD%d\n",
                                 vd->id);
                        continue;
                }

                for (opp_id = 0; opp_id < NUM_OPPS; opp_id++) {
                        opp = &vd->opps[opp_id];

                        if (!opp->freq)
                                continue;

                        volt = priv->vd_config->efuse_xlate(priv, vd->id,
                                                            opp_id);
                        if (volt)
                                opp->volt = volt;
                }
        }

        for (vd = priv->vd_config->vds; vd->id >= 0; vd++) {
                if (vd->flags & VD_FLAG_INIT_DONE)
                        continue;

                k3_avs_program_voltage(priv, vd, vd->opp);
        }

        return 0;
}

static struct vd_data am654_vd_data[] = {
        {
                .id = AM6_VDD_CORE,
                .dev_id = 82, /* AM6_DEV_CBASS0 */
                .clk_id = 0, /* main sysclk0 */
                .opp = AM6_OPP_NOM,
                .opps = {
                        [AM6_OPP_NOM] = {
                                .volt = 1000000,
                                .freq = 250000000, /* CBASS0 */
                        },
                },
        },
        {
                .id = AM6_VDD_MPU0,
                .dev_id = 202, /* AM6_DEV_COMPUTE_CLUSTER_A53_0 */
                .clk_id = 0, /* ARM clock */
                .opp = AM6_OPP_NOM,
                .opps = {
                        [AM6_OPP_NOM] = {
                                .volt = 1100000,
                                .freq = 800000000,
                        },
                        [AM6_OPP_OD] = {
                                .volt = 1200000,
                                .freq = 1000000000,
                        },
                        [AM6_OPP_TURBO] = {
                                .volt = 1240000,
                                .freq = 1100000000,
                        },
                },
        },
        {
                .id = AM6_VDD_MPU1,
                .opp = AM6_OPP_NOM,
                .dev_id = 204, /* AM6_DEV_COMPUTE_CLUSTER_A53_2 */
                .clk_id = 0, /* ARM clock */
                .opps = {
                        [AM6_OPP_NOM] = {
                                .volt = 1100000,
                                .freq = 800000000,
                        },
                        [AM6_OPP_OD] = {
                                .volt = 1200000,
                                .freq = 1000000000,
                        },
                        [AM6_OPP_TURBO] = {
                                .volt = 1240000,
                                .freq = 1100000000,
                        },
                },
        },
        { .id = -1 },
};

static struct vd_data j721e_vd_data[] = {
        {
                .id = J721E_VDD_MPU,
                .opp = AM6_OPP_NOM,
                .dev_id = 202, /* J721E_DEV_A72SS0_CORE0 */
                .clk_id = 2, /* ARM clock */
                .opps = {
                        [AM6_OPP_NOM] = {
                                .volt = 880000, /* TBD in DM */
                                .freq = 2000000000,
                        },
                },
        },
        { .id = -1 },
};

static struct vd_config j721e_vd_config = {
        .efuse_xlate = am6_efuse_xlate,
        .vds = j721e_vd_data,
};

static struct vd_config am654_vd_config = {
        .efuse_xlate = am6_efuse_xlate,
        .vds = am654_vd_data,
};

static const struct udevice_id k3_avs_ids[] = {
        { .compatible = "ti,am654-avs", .data = (ulong)&am654_vd_config },
        { .compatible = "ti,j721e-avs", .data = (ulong)&j721e_vd_config },
        {}
};

U_BOOT_DRIVER(k3_avs) = {
        .name = "k3_avs",
        .of_match = k3_avs_ids,
        .id = UCLASS_MISC,
        .probe = k3_avs_probe,
        .priv_auto      = sizeof(struct k3_avs_privdata),
};