root/drivers/clk/pistachio/clk-pll.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Google, Inc.
 */

#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/slab.h>

#include "clk.h"

#define PLL_STATUS                      0x0
#define PLL_STATUS_LOCK                 BIT(0)

#define PLL_CTRL1                       0x4
#define PLL_CTRL1_REFDIV_SHIFT          0
#define PLL_CTRL1_REFDIV_MASK           0x3f
#define PLL_CTRL1_FBDIV_SHIFT           6
#define PLL_CTRL1_FBDIV_MASK            0xfff
#define PLL_INT_CTRL1_POSTDIV1_SHIFT    18
#define PLL_INT_CTRL1_POSTDIV1_MASK     0x7
#define PLL_INT_CTRL1_POSTDIV2_SHIFT    21
#define PLL_INT_CTRL1_POSTDIV2_MASK     0x7
#define PLL_INT_CTRL1_PD                BIT(24)
#define PLL_INT_CTRL1_DSMPD             BIT(25)
#define PLL_INT_CTRL1_FOUTPOSTDIVPD     BIT(26)
#define PLL_INT_CTRL1_FOUTVCOPD         BIT(27)

#define PLL_CTRL2                       0x8
#define PLL_FRAC_CTRL2_FRAC_SHIFT       0
#define PLL_FRAC_CTRL2_FRAC_MASK        0xffffff
#define PLL_FRAC_CTRL2_POSTDIV1_SHIFT   24
#define PLL_FRAC_CTRL2_POSTDIV1_MASK    0x7
#define PLL_FRAC_CTRL2_POSTDIV2_SHIFT   27
#define PLL_FRAC_CTRL2_POSTDIV2_MASK    0x7
#define PLL_INT_CTRL2_BYPASS            BIT(28)

#define PLL_CTRL3                       0xc
#define PLL_FRAC_CTRL3_PD               BIT(0)
#define PLL_FRAC_CTRL3_DACPD            BIT(1)
#define PLL_FRAC_CTRL3_DSMPD            BIT(2)
#define PLL_FRAC_CTRL3_FOUTPOSTDIVPD    BIT(3)
#define PLL_FRAC_CTRL3_FOUT4PHASEPD     BIT(4)
#define PLL_FRAC_CTRL3_FOUTVCOPD        BIT(5)

#define PLL_CTRL4                       0x10
#define PLL_FRAC_CTRL4_BYPASS           BIT(28)

#define MIN_PFD                         9600000UL
#define MIN_VCO_LA                      400000000UL
#define MAX_VCO_LA                      1600000000UL
#define MIN_VCO_FRAC_INT                600000000UL
#define MAX_VCO_FRAC_INT                1600000000UL
#define MIN_VCO_FRAC_FRAC               600000000UL
#define MAX_VCO_FRAC_FRAC               2400000000UL
#define MIN_OUTPUT_LA                   8000000UL
#define MAX_OUTPUT_LA                   1600000000UL
#define MIN_OUTPUT_FRAC                 12000000UL
#define MAX_OUTPUT_FRAC                 1600000000UL

/* Fractional PLL operating modes */
enum pll_mode {
        PLL_MODE_FRAC,
        PLL_MODE_INT,
};

struct pistachio_clk_pll {
        struct clk_hw hw;
        void __iomem *base;
        struct pistachio_pll_rate_table *rates;
        unsigned int nr_rates;
};

static inline u32 pll_readl(struct pistachio_clk_pll *pll, u32 reg)
{
        return readl(pll->base + reg);
}

static inline void pll_writel(struct pistachio_clk_pll *pll, u32 val, u32 reg)
{
        writel(val, pll->base + reg);
}

static inline void pll_lock(struct pistachio_clk_pll *pll)
{
        while (!(pll_readl(pll, PLL_STATUS) & PLL_STATUS_LOCK))
                cpu_relax();
}

static inline u64 do_div_round_closest(u64 dividend, u64 divisor)
{
        dividend += divisor / 2;
        return div64_u64(dividend, divisor);
}

static inline struct pistachio_clk_pll *to_pistachio_pll(struct clk_hw *hw)
{
        return container_of(hw, struct pistachio_clk_pll, hw);
}

static inline enum pll_mode pll_frac_get_mode(struct clk_hw *hw)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u32 val;

        val = pll_readl(pll, PLL_CTRL3) & PLL_FRAC_CTRL3_DSMPD;
        return val ? PLL_MODE_INT : PLL_MODE_FRAC;
}

static inline void pll_frac_set_mode(struct clk_hw *hw, enum pll_mode mode)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u32 val;

        val = pll_readl(pll, PLL_CTRL3);
        if (mode == PLL_MODE_INT)
                val |= PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD;
        else
                val &= ~(PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD);

        pll_writel(pll, val, PLL_CTRL3);
}

static struct pistachio_pll_rate_table *
pll_get_params(struct pistachio_clk_pll *pll, unsigned long fref,
               unsigned long fout)
{
        unsigned int i;

        for (i = 0; i < pll->nr_rates; i++) {
                if (pll->rates[i].fref == fref && pll->rates[i].fout == fout)
                        return &pll->rates[i];
        }

        return NULL;
}

static int pll_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        unsigned int i;

        for (i = 0; i < pll->nr_rates; i++) {
                if (i > 0 && pll->rates[i].fref == req->best_parent_rate &&
                    pll->rates[i].fout <= req->rate) {
                        req->rate = pll->rates[i - 1].fout;

                        return 0;
                }
        }

        req->rate = pll->rates[0].fout;

        return 0;
}

static int pll_gf40lp_frac_enable(struct clk_hw *hw)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u32 val;

        val = pll_readl(pll, PLL_CTRL3);
        val &= ~(PLL_FRAC_CTRL3_PD | PLL_FRAC_CTRL3_FOUTPOSTDIVPD |
                 PLL_FRAC_CTRL3_FOUT4PHASEPD | PLL_FRAC_CTRL3_FOUTVCOPD);
        pll_writel(pll, val, PLL_CTRL3);

        val = pll_readl(pll, PLL_CTRL4);
        val &= ~PLL_FRAC_CTRL4_BYPASS;
        pll_writel(pll, val, PLL_CTRL4);

        pll_lock(pll);

        return 0;
}

static void pll_gf40lp_frac_disable(struct clk_hw *hw)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u32 val;

        val = pll_readl(pll, PLL_CTRL3);
        val |= PLL_FRAC_CTRL3_PD;
        pll_writel(pll, val, PLL_CTRL3);
}

static int pll_gf40lp_frac_is_enabled(struct clk_hw *hw)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);

        return !(pll_readl(pll, PLL_CTRL3) & PLL_FRAC_CTRL3_PD);
}

static int pll_gf40lp_frac_set_rate(struct clk_hw *hw, unsigned long rate,
                                    unsigned long parent_rate)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        struct pistachio_pll_rate_table *params;
        int enabled = pll_gf40lp_frac_is_enabled(hw);
        u64 val, vco, old_postdiv1, old_postdiv2;
        const char *name = clk_hw_get_name(hw);

        if (rate < MIN_OUTPUT_FRAC || rate > MAX_OUTPUT_FRAC)
                return -EINVAL;

        params = pll_get_params(pll, parent_rate, rate);
        if (!params || !params->refdiv)
                return -EINVAL;

        /* calculate vco */
        vco = params->fref;
        vco *= (params->fbdiv << 24) + params->frac;
        vco = div64_u64(vco, params->refdiv << 24);

        if (vco < MIN_VCO_FRAC_FRAC || vco > MAX_VCO_FRAC_FRAC)
                pr_warn("%s: VCO %llu is out of range %lu..%lu\n", name, vco,
                        MIN_VCO_FRAC_FRAC, MAX_VCO_FRAC_FRAC);

        val = div64_u64(params->fref, params->refdiv);
        if (val < MIN_PFD)
                pr_warn("%s: PFD %llu is too low (min %lu)\n",
                        name, val, MIN_PFD);
        if (val > vco / 16)
                pr_warn("%s: PFD %llu is too high (max %llu)\n",
                        name, val, vco / 16);

        val = pll_readl(pll, PLL_CTRL1);
        val &= ~((PLL_CTRL1_REFDIV_MASK << PLL_CTRL1_REFDIV_SHIFT) |
                 (PLL_CTRL1_FBDIV_MASK << PLL_CTRL1_FBDIV_SHIFT));
        val |= (params->refdiv << PLL_CTRL1_REFDIV_SHIFT) |
                (params->fbdiv << PLL_CTRL1_FBDIV_SHIFT);
        pll_writel(pll, val, PLL_CTRL1);

        val = pll_readl(pll, PLL_CTRL2);

        old_postdiv1 = (val >> PLL_FRAC_CTRL2_POSTDIV1_SHIFT) &
                       PLL_FRAC_CTRL2_POSTDIV1_MASK;
        old_postdiv2 = (val >> PLL_FRAC_CTRL2_POSTDIV2_SHIFT) &
                       PLL_FRAC_CTRL2_POSTDIV2_MASK;
        if (enabled &&
            (params->postdiv1 != old_postdiv1 ||
             params->postdiv2 != old_postdiv2))
                pr_warn("%s: changing postdiv while PLL is enabled\n", name);

        if (params->postdiv2 > params->postdiv1)
                pr_warn("%s: postdiv2 should not exceed postdiv1\n", name);

        val &= ~((PLL_FRAC_CTRL2_FRAC_MASK << PLL_FRAC_CTRL2_FRAC_SHIFT) |
                 (PLL_FRAC_CTRL2_POSTDIV1_MASK <<
                  PLL_FRAC_CTRL2_POSTDIV1_SHIFT) |
                 (PLL_FRAC_CTRL2_POSTDIV2_MASK <<
                  PLL_FRAC_CTRL2_POSTDIV2_SHIFT));
        val |= (params->frac << PLL_FRAC_CTRL2_FRAC_SHIFT) |
                (params->postdiv1 << PLL_FRAC_CTRL2_POSTDIV1_SHIFT) |
                (params->postdiv2 << PLL_FRAC_CTRL2_POSTDIV2_SHIFT);
        pll_writel(pll, val, PLL_CTRL2);

        /* set operating mode */
        if (params->frac)
                pll_frac_set_mode(hw, PLL_MODE_FRAC);
        else
                pll_frac_set_mode(hw, PLL_MODE_INT);

        if (enabled)
                pll_lock(pll);

        return 0;
}

static unsigned long pll_gf40lp_frac_recalc_rate(struct clk_hw *hw,
                                                 unsigned long parent_rate)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u64 val, prediv, fbdiv, frac, postdiv1, postdiv2, rate;

        val = pll_readl(pll, PLL_CTRL1);
        prediv = (val >> PLL_CTRL1_REFDIV_SHIFT) & PLL_CTRL1_REFDIV_MASK;
        fbdiv = (val >> PLL_CTRL1_FBDIV_SHIFT) & PLL_CTRL1_FBDIV_MASK;

        val = pll_readl(pll, PLL_CTRL2);
        postdiv1 = (val >> PLL_FRAC_CTRL2_POSTDIV1_SHIFT) &
                PLL_FRAC_CTRL2_POSTDIV1_MASK;
        postdiv2 = (val >> PLL_FRAC_CTRL2_POSTDIV2_SHIFT) &
                PLL_FRAC_CTRL2_POSTDIV2_MASK;
        frac = (val >> PLL_FRAC_CTRL2_FRAC_SHIFT) & PLL_FRAC_CTRL2_FRAC_MASK;

        /* get operating mode (int/frac) and calculate rate accordingly */
        rate = parent_rate;
        if (pll_frac_get_mode(hw) == PLL_MODE_FRAC)
                rate *= (fbdiv << 24) + frac;
        else
                rate *= (fbdiv << 24);

        rate = do_div_round_closest(rate, (prediv * postdiv1 * postdiv2) << 24);

        return rate;
}

static const struct clk_ops pll_gf40lp_frac_ops = {
        .enable = pll_gf40lp_frac_enable,
        .disable = pll_gf40lp_frac_disable,
        .is_enabled = pll_gf40lp_frac_is_enabled,
        .recalc_rate = pll_gf40lp_frac_recalc_rate,
        .determine_rate = pll_determine_rate,
        .set_rate = pll_gf40lp_frac_set_rate,
};

static const struct clk_ops pll_gf40lp_frac_fixed_ops = {
        .enable = pll_gf40lp_frac_enable,
        .disable = pll_gf40lp_frac_disable,
        .is_enabled = pll_gf40lp_frac_is_enabled,
        .recalc_rate = pll_gf40lp_frac_recalc_rate,
};

static int pll_gf40lp_laint_enable(struct clk_hw *hw)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u32 val;

        val = pll_readl(pll, PLL_CTRL1);
        val &= ~(PLL_INT_CTRL1_PD |
                 PLL_INT_CTRL1_FOUTPOSTDIVPD | PLL_INT_CTRL1_FOUTVCOPD);
        pll_writel(pll, val, PLL_CTRL1);

        val = pll_readl(pll, PLL_CTRL2);
        val &= ~PLL_INT_CTRL2_BYPASS;
        pll_writel(pll, val, PLL_CTRL2);

        pll_lock(pll);

        return 0;
}

static void pll_gf40lp_laint_disable(struct clk_hw *hw)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u32 val;

        val = pll_readl(pll, PLL_CTRL1);
        val |= PLL_INT_CTRL1_PD;
        pll_writel(pll, val, PLL_CTRL1);
}

static int pll_gf40lp_laint_is_enabled(struct clk_hw *hw)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);

        return !(pll_readl(pll, PLL_CTRL1) & PLL_INT_CTRL1_PD);
}

static int pll_gf40lp_laint_set_rate(struct clk_hw *hw, unsigned long rate,
                                     unsigned long parent_rate)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        struct pistachio_pll_rate_table *params;
        int enabled = pll_gf40lp_laint_is_enabled(hw);
        u32 val, vco, old_postdiv1, old_postdiv2;
        const char *name = clk_hw_get_name(hw);

        if (rate < MIN_OUTPUT_LA || rate > MAX_OUTPUT_LA)
                return -EINVAL;

        params = pll_get_params(pll, parent_rate, rate);
        if (!params || !params->refdiv)
                return -EINVAL;

        vco = div_u64(params->fref * params->fbdiv, params->refdiv);
        if (vco < MIN_VCO_LA || vco > MAX_VCO_LA)
                pr_warn("%s: VCO %u is out of range %lu..%lu\n", name, vco,
                        MIN_VCO_LA, MAX_VCO_LA);

        val = div_u64(params->fref, params->refdiv);
        if (val < MIN_PFD)
                pr_warn("%s: PFD %u is too low (min %lu)\n",
                        name, val, MIN_PFD);
        if (val > vco / 16)
                pr_warn("%s: PFD %u is too high (max %u)\n",
                        name, val, vco / 16);

        val = pll_readl(pll, PLL_CTRL1);

        old_postdiv1 = (val >> PLL_INT_CTRL1_POSTDIV1_SHIFT) &
                       PLL_INT_CTRL1_POSTDIV1_MASK;
        old_postdiv2 = (val >> PLL_INT_CTRL1_POSTDIV2_SHIFT) &
                       PLL_INT_CTRL1_POSTDIV2_MASK;
        if (enabled &&
            (params->postdiv1 != old_postdiv1 ||
             params->postdiv2 != old_postdiv2))
                pr_warn("%s: changing postdiv while PLL is enabled\n", name);

        if (params->postdiv2 > params->postdiv1)
                pr_warn("%s: postdiv2 should not exceed postdiv1\n", name);

        val &= ~((PLL_CTRL1_REFDIV_MASK << PLL_CTRL1_REFDIV_SHIFT) |
                 (PLL_CTRL1_FBDIV_MASK << PLL_CTRL1_FBDIV_SHIFT) |
                 (PLL_INT_CTRL1_POSTDIV1_MASK << PLL_INT_CTRL1_POSTDIV1_SHIFT) |
                 (PLL_INT_CTRL1_POSTDIV2_MASK << PLL_INT_CTRL1_POSTDIV2_SHIFT));
        val |= (params->refdiv << PLL_CTRL1_REFDIV_SHIFT) |
                (params->fbdiv << PLL_CTRL1_FBDIV_SHIFT) |
                (params->postdiv1 << PLL_INT_CTRL1_POSTDIV1_SHIFT) |
                (params->postdiv2 << PLL_INT_CTRL1_POSTDIV2_SHIFT);
        pll_writel(pll, val, PLL_CTRL1);

        if (enabled)
                pll_lock(pll);

        return 0;
}

static unsigned long pll_gf40lp_laint_recalc_rate(struct clk_hw *hw,
                                                  unsigned long parent_rate)
{
        struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
        u32 val, prediv, fbdiv, postdiv1, postdiv2;
        u64 rate = parent_rate;

        val = pll_readl(pll, PLL_CTRL1);
        prediv = (val >> PLL_CTRL1_REFDIV_SHIFT) & PLL_CTRL1_REFDIV_MASK;
        fbdiv = (val >> PLL_CTRL1_FBDIV_SHIFT) & PLL_CTRL1_FBDIV_MASK;
        postdiv1 = (val >> PLL_INT_CTRL1_POSTDIV1_SHIFT) &
                PLL_INT_CTRL1_POSTDIV1_MASK;
        postdiv2 = (val >> PLL_INT_CTRL1_POSTDIV2_SHIFT) &
                PLL_INT_CTRL1_POSTDIV2_MASK;

        rate *= fbdiv;
        rate = do_div_round_closest(rate, prediv * postdiv1 * postdiv2);

        return rate;
}

static const struct clk_ops pll_gf40lp_laint_ops = {
        .enable = pll_gf40lp_laint_enable,
        .disable = pll_gf40lp_laint_disable,
        .is_enabled = pll_gf40lp_laint_is_enabled,
        .recalc_rate = pll_gf40lp_laint_recalc_rate,
        .determine_rate = pll_determine_rate,
        .set_rate = pll_gf40lp_laint_set_rate,
};

static const struct clk_ops pll_gf40lp_laint_fixed_ops = {
        .enable = pll_gf40lp_laint_enable,
        .disable = pll_gf40lp_laint_disable,
        .is_enabled = pll_gf40lp_laint_is_enabled,
        .recalc_rate = pll_gf40lp_laint_recalc_rate,
};

static struct clk *pll_register(const char *name, const char *parent_name,
                                unsigned long flags, void __iomem *base,
                                enum pistachio_pll_type type,
                                struct pistachio_pll_rate_table *rates,
                                unsigned int nr_rates)
{
        struct pistachio_clk_pll *pll;
        struct clk_init_data init;
        struct clk *clk;

        pll = kzalloc_obj(*pll);
        if (!pll)
                return ERR_PTR(-ENOMEM);

        init.name = name;
        init.flags = flags | CLK_GET_RATE_NOCACHE;
        init.parent_names = &parent_name;
        init.num_parents = 1;

        switch (type) {
        case PLL_GF40LP_FRAC:
                if (rates)
                        init.ops = &pll_gf40lp_frac_ops;
                else
                        init.ops = &pll_gf40lp_frac_fixed_ops;
                break;
        case PLL_GF40LP_LAINT:
                if (rates)
                        init.ops = &pll_gf40lp_laint_ops;
                else
                        init.ops = &pll_gf40lp_laint_fixed_ops;
                break;
        default:
                pr_err("Unrecognized PLL type %u\n", type);
                kfree(pll);
                return ERR_PTR(-EINVAL);
        }

        pll->hw.init = &init;
        pll->base = base;
        pll->rates = rates;
        pll->nr_rates = nr_rates;

        clk = clk_register(NULL, &pll->hw);
        if (IS_ERR(clk))
                kfree(pll);

        return clk;
}

void pistachio_clk_register_pll(struct pistachio_clk_provider *p,
                                struct pistachio_pll *pll,
                                unsigned int num)
{
        struct clk *clk;
        unsigned int i;

        for (i = 0; i < num; i++) {
                clk = pll_register(pll[i].name, pll[i].parent,
                                   0, p->base + pll[i].reg_base,
                                   pll[i].type, pll[i].rates,
                                   pll[i].nr_rates);
                p->clk_data.clks[pll[i].id] = clk;
        }
}