// SPDX-License-Identifier: GPL-2.0
/*
 * Zynq UltraScale+ MPSoC PLL driver
 *
 *  Copyright (C) 2016-2018 Xilinx
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/slab.h>
#include "clk-zynqmp.h"

/**
 * struct zynqmp_pll - PLL clock
 * @hw:         Handle between common and hardware-specific interfaces
 * @clk_id:     PLL clock ID
 * @set_pll_mode:       Whether an IOCTL_SET_PLL_FRAC_MODE request be sent to ATF
 */
struct zynqmp_pll {
        struct clk_hw hw;
        u32 clk_id;
        bool set_pll_mode;
};

#define to_zynqmp_pll(_hw)      container_of(_hw, struct zynqmp_pll, hw)

#define PLL_FBDIV_MIN   25
#define PLL_FBDIV_MAX   125

#define PS_PLL_VCO_MIN 1500000000
#define PS_PLL_VCO_MAX 3000000000UL

enum pll_mode {
        PLL_MODE_INT = 0,
        PLL_MODE_FRAC = 1,
        PLL_MODE_ERROR = 2,
};

#define FRAC_OFFSET 0x8
#define PLLFCFG_FRAC_EN BIT(31)
#define FRAC_DIV  BIT(16)  /* 2^16 */

/**
 * zynqmp_pll_get_mode() - Get mode of PLL
 * @hw:         Handle between common and hardware-specific interfaces
 *
 * Return: Mode of PLL
 */
static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
{
        struct zynqmp_pll *clk = to_zynqmp_pll(hw);
        u32 clk_id = clk->clk_id;
        const char *clk_name = clk_hw_get_name(hw);
        u32 ret_payload[PAYLOAD_ARG_CNT];
        int ret;

        ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
        if (ret) {
                pr_debug("%s() PLL get frac mode failed for %s, ret = %d\n",
                         __func__, clk_name, ret);
                return PLL_MODE_ERROR;
        }

        return ret_payload[1];
}

/**
 * zynqmp_pll_set_mode() - Set the PLL mode
 * @hw:         Handle between common and hardware-specific interfaces
 * @on:         Flag to determine the mode
 */
static inline void zynqmp_pll_set_mode(struct clk_hw *hw, bool on)
{
        struct zynqmp_pll *clk = to_zynqmp_pll(hw);
        u32 clk_id = clk->clk_id;
        const char *clk_name = clk_hw_get_name(hw);
        int ret;
        u32 mode;

        if (on)
                mode = PLL_MODE_FRAC;
        else
                mode = PLL_MODE_INT;

        ret = zynqmp_pm_set_pll_frac_mode(clk_id, mode);
        if (ret)
                pr_debug("%s() PLL set frac mode failed for %s, ret = %d\n",
                         __func__, clk_name, ret);
        else
                clk->set_pll_mode = true;
}

/**
 * zynqmp_pll_round_rate() - Round a clock frequency
 * @hw:         Handle between common and hardware-specific interfaces
 * @rate:       Desired clock frequency
 * @prate:      Clock frequency of parent clock
 *
 * Return: Frequency closest to @rate the hardware can generate
 */
static long zynqmp_pll_round_rate(struct clk_hw *hw, unsigned long rate,
                                  unsigned long *prate)
{
        u32 fbdiv;
        long rate_div, f;

        /* Enable the fractional mode if needed */
        rate_div = (rate * FRAC_DIV) / *prate;
        f = rate_div % FRAC_DIV;
        if (f) {
                if (rate > PS_PLL_VCO_MAX) {
                        fbdiv = rate / PS_PLL_VCO_MAX;
                        rate = rate / (fbdiv + 1);
                }
                if (rate < PS_PLL_VCO_MIN) {
                        fbdiv = DIV_ROUND_UP(PS_PLL_VCO_MIN, rate);
                        rate = rate * fbdiv;
                }
                return rate;
        }

        fbdiv = DIV_ROUND_CLOSEST(rate, *prate);
        fbdiv = clamp_t(u32, fbdiv, PLL_FBDIV_MIN, PLL_FBDIV_MAX);
        return *prate * fbdiv;
}

/**
 * zynqmp_pll_recalc_rate() - Recalculate clock frequency
 * @hw:                 Handle between common and hardware-specific interfaces
 * @parent_rate:        Clock frequency of parent clock
 *
 * Return: Current clock frequency or 0 in case of error
 */
static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
                                            unsigned long parent_rate)
{
        struct zynqmp_pll *clk = to_zynqmp_pll(hw);
        u32 clk_id = clk->clk_id;
        const char *clk_name = clk_hw_get_name(hw);
        u32 fbdiv, data;
        unsigned long rate, frac;
        u32 ret_payload[PAYLOAD_ARG_CNT];
        int ret;
        enum pll_mode mode;

        ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
        if (ret) {
                pr_debug("%s() get divider failed for %s, ret = %d\n",
                         __func__, clk_name, ret);
                return 0ul;
        }

        mode = zynqmp_pll_get_mode(hw);
        if (mode == PLL_MODE_ERROR)
                return 0ul;

        rate =  parent_rate * fbdiv;
        if (mode == PLL_MODE_FRAC) {
                zynqmp_pm_get_pll_frac_data(clk_id, ret_payload);
                data = ret_payload[1];
                frac = (parent_rate * data) / FRAC_DIV;
                rate = rate + frac;
        }

        return rate;
}

/**
 * zynqmp_pll_set_rate() - Set rate of PLL
 * @hw:                 Handle between common and hardware-specific interfaces
 * @rate:               Frequency of clock to be set
 * @parent_rate:        Clock frequency of parent clock
 *
 * Set PLL divider to set desired rate.
 *
 * Returns:            rate which is set on success else error code
 */
static int zynqmp_pll_set_rate(struct clk_hw *hw, unsigned long rate,
                               unsigned long parent_rate)
{
        struct zynqmp_pll *clk = to_zynqmp_pll(hw);
        u32 clk_id = clk->clk_id;
        const char *clk_name = clk_hw_get_name(hw);
        u32 fbdiv;
        long rate_div, frac, m, f;
        int ret;

        rate_div = (rate * FRAC_DIV) / parent_rate;
        f = rate_div % FRAC_DIV;
        zynqmp_pll_set_mode(hw, !!f);

        if (f) {
                m = rate_div / FRAC_DIV;
                m = clamp_t(u32, m, (PLL_FBDIV_MIN), (PLL_FBDIV_MAX));
                rate = parent_rate * m;
                frac = (parent_rate * f) / FRAC_DIV;

                ret = zynqmp_pm_clock_setdivider(clk_id, m);
                if (ret == -EUSERS)
                        WARN(1, "More than allowed devices are using the %s, which is forbidden\n",
                             clk_name);
                else if (ret)
                        pr_debug("%s() set divider failed for %s, ret = %d\n",
                                 __func__, clk_name, ret);
                zynqmp_pm_set_pll_frac_data(clk_id, f);

                return rate + frac;
        }

        fbdiv = DIV_ROUND_CLOSEST(rate, parent_rate);
        fbdiv = clamp_t(u32, fbdiv, PLL_FBDIV_MIN, PLL_FBDIV_MAX);
        ret = zynqmp_pm_clock_setdivider(clk_id, fbdiv);
        if (ret)
                pr_debug("%s() set divider failed for %s, ret = %d\n",
                         __func__, clk_name, ret);

        return parent_rate * fbdiv;
}

/**
 * zynqmp_pll_is_enabled() - Check if a clock is enabled
 * @hw:         Handle between common and hardware-specific interfaces
 *
 * Return: 1 if the clock is enabled, 0 otherwise
 */
static int zynqmp_pll_is_enabled(struct clk_hw *hw)
{
        struct zynqmp_pll *clk = to_zynqmp_pll(hw);
        const char *clk_name = clk_hw_get_name(hw);
        u32 clk_id = clk->clk_id;
        unsigned int state;
        int ret;

        ret = zynqmp_pm_clock_getstate(clk_id, &state);
        if (ret) {
                pr_debug("%s() clock get state failed for %s, ret = %d\n",
                         __func__, clk_name, ret);
                return -EIO;
        }

        return state ? 1 : 0;
}

/**
 * zynqmp_pll_enable() - Enable clock
 * @hw:         Handle between common and hardware-specific interfaces
 *
 * Return: 0 on success else error code
 */
static int zynqmp_pll_enable(struct clk_hw *hw)
{
        struct zynqmp_pll *clk = to_zynqmp_pll(hw);
        const char *clk_name = clk_hw_get_name(hw);
        u32 clk_id = clk->clk_id;
        int ret;

        /*
         * Don't skip enabling clock if there is an IOCTL_SET_PLL_FRAC_MODE request
         * that has been sent to ATF.
         */
        if (zynqmp_pll_is_enabled(hw) && (!clk->set_pll_mode))
                return 0;

        clk->set_pll_mode = false;

        ret = zynqmp_pm_clock_enable(clk_id);
        if (ret)
                pr_debug("%s() clock enable failed for %s, ret = %d\n",
                         __func__, clk_name, ret);

        return ret;
}

/**
 * zynqmp_pll_disable() - Disable clock
 * @hw:         Handle between common and hardware-specific interfaces
 */
static void zynqmp_pll_disable(struct clk_hw *hw)
{
        struct zynqmp_pll *clk = to_zynqmp_pll(hw);
        const char *clk_name = clk_hw_get_name(hw);
        u32 clk_id = clk->clk_id;
        int ret;

        if (!zynqmp_pll_is_enabled(hw))
                return;

        ret = zynqmp_pm_clock_disable(clk_id);
        if (ret)
                pr_debug("%s() clock disable failed for %s, ret = %d\n",
                         __func__, clk_name, ret);
}

static const struct clk_ops zynqmp_pll_ops = {
        .enable = zynqmp_pll_enable,
        .disable = zynqmp_pll_disable,
        .is_enabled = zynqmp_pll_is_enabled,
        .round_rate = zynqmp_pll_round_rate,
        .recalc_rate = zynqmp_pll_recalc_rate,
        .set_rate = zynqmp_pll_set_rate,
};

/**
 * zynqmp_clk_register_pll() - Register PLL with the clock framework
 * @name:               PLL name
 * @clk_id:             Clock ID
 * @parents:            Name of this clock's parents
 * @num_parents:        Number of parents
 * @nodes:              Clock topology node
 *
 * Return: clock hardware to the registered clock
 */
struct clk_hw *zynqmp_clk_register_pll(const char *name, u32 clk_id,
                                       const char * const *parents,
                                       u8 num_parents,
                                       const struct clock_topology *nodes)
{
        struct zynqmp_pll *pll;
        struct clk_hw *hw;
        struct clk_init_data init;
        int ret;

        init.name = name;
        init.ops = &zynqmp_pll_ops;

        init.flags = zynqmp_clk_map_common_ccf_flags(nodes->flag);

        init.parent_names = parents;
        init.num_parents = 1;

        pll = kzalloc(sizeof(*pll), GFP_KERNEL);
        if (!pll)
                return ERR_PTR(-ENOMEM);

        pll->hw.init = &init;
        pll->clk_id = clk_id;

        hw = &pll->hw;
        ret = clk_hw_register(NULL, hw);
        if (ret) {
                kfree(pll);
                return ERR_PTR(ret);
        }

        clk_hw_set_rate_range(hw, PS_PLL_VCO_MIN, PS_PLL_VCO_MAX);

        return hw;
}