/*
 * Copyright (c) 2013, The Linux Foundation. All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/clk-provider.h>
#include <linux/regmap.h>

#include <asm/div64.h>

#include "clk-rcg.h"

static u32 ns_to_src(struct src_sel *s, u32 ns)
{
        ns >>= s->src_sel_shift;
        ns &= SRC_SEL_MASK;
        return ns;
}

static u32 src_to_ns(struct src_sel *s, u8 src, u32 ns)
{
        u32 mask;

        mask = SRC_SEL_MASK;
        mask <<= s->src_sel_shift;
        ns &= ~mask;

        ns |= src << s->src_sel_shift;
        return ns;
}

static u8 clk_rcg_get_parent(struct clk_hw *hw)
{
        struct clk_rcg *rcg = to_clk_rcg(hw);
        int num_parents = __clk_get_num_parents(hw->clk);
        u32 ns;
        int i;

        regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
        ns = ns_to_src(&rcg->s, ns);
        for (i = 0; i < num_parents; i++)
                if (ns == rcg->s.parent_map[i])
                        return i;

        return -EINVAL;
}

static int reg_to_bank(struct clk_dyn_rcg *rcg, u32 bank)
{
        bank &= BIT(rcg->mux_sel_bit);
        return !!bank;
}

static u8 clk_dyn_rcg_get_parent(struct clk_hw *hw)
{
        struct clk_dyn_rcg *rcg = to_clk_dyn_rcg(hw);
        int num_parents = __clk_get_num_parents(hw->clk);
        u32 ns, ctl;
        int bank;
        int i;
        struct src_sel *s;

        regmap_read(rcg->clkr.regmap, rcg->clkr.enable_reg, &ctl);
        bank = reg_to_bank(rcg, ctl);
        s = &rcg->s[bank];

        regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
        ns = ns_to_src(s, ns);

        for (i = 0; i < num_parents; i++)
                if (ns == s->parent_map[i])
                        return i;

        return -EINVAL;
}

static int clk_rcg_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_rcg *rcg = to_clk_rcg(hw);
        u32 ns;

        regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
        ns = src_to_ns(&rcg->s, rcg->s.parent_map[index], ns);
        regmap_write(rcg->clkr.regmap, rcg->ns_reg, ns);

        return 0;
}

static u32 md_to_m(struct mn *mn, u32 md)
{
        md >>= mn->m_val_shift;
        md &= BIT(mn->width) - 1;
        return md;
}

static u32 ns_to_pre_div(struct pre_div *p, u32 ns)
{
        ns >>= p->pre_div_shift;
        ns &= BIT(p->pre_div_width) - 1;
        return ns;
}

static u32 pre_div_to_ns(struct pre_div *p, u8 pre_div, u32 ns)
{
        u32 mask;

        mask = BIT(p->pre_div_width) - 1;
        mask <<= p->pre_div_shift;
        ns &= ~mask;

        ns |= pre_div << p->pre_div_shift;
        return ns;
}

static u32 mn_to_md(struct mn *mn, u32 m, u32 n, u32 md)
{
        u32 mask, mask_w;

        mask_w = BIT(mn->width) - 1;
        mask = (mask_w << mn->m_val_shift) | mask_w;
        md &= ~mask;

        if (n) {
                m <<= mn->m_val_shift;
                md |= m;
                md |= ~n & mask_w;
        }

        return md;
}

static u32 ns_m_to_n(struct mn *mn, u32 ns, u32 m)
{
        ns = ~ns >> mn->n_val_shift;
        ns &= BIT(mn->width) - 1;
        return ns + m;
}

static u32 reg_to_mnctr_mode(struct mn *mn, u32 val)
{
        val >>= mn->mnctr_mode_shift;
        val &= MNCTR_MODE_MASK;
        return val;
}

static u32 mn_to_ns(struct mn *mn, u32 m, u32 n, u32 ns)
{
        u32 mask;

        mask = BIT(mn->width) - 1;
        mask <<= mn->n_val_shift;
        ns &= ~mask;

        if (n) {
                n = n - m;
                n = ~n;
                n &= BIT(mn->width) - 1;
                n <<= mn->n_val_shift;
                ns |= n;
        }

        return ns;
}

static u32 mn_to_reg(struct mn *mn, u32 m, u32 n, u32 val)
{
        u32 mask;

        mask = MNCTR_MODE_MASK << mn->mnctr_mode_shift;
        mask |= BIT(mn->mnctr_en_bit);
        val &= ~mask;

        if (n) {
                val |= BIT(mn->mnctr_en_bit);
                val |= MNCTR_MODE_DUAL << mn->mnctr_mode_shift;
        }

        return val;
}

static void configure_bank(struct clk_dyn_rcg *rcg, const struct freq_tbl *f)
{
        u32 ns, md, ctl, *regp;
        int bank, new_bank;
        struct mn *mn;
        struct pre_div *p;
        struct src_sel *s;
        bool enabled;
        u32 md_reg;
        u32 bank_reg;
        bool banked_mn = !!rcg->mn[1].width;
        struct clk_hw *hw = &rcg->clkr.hw;

        enabled = __clk_is_enabled(hw->clk);

        regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
        regmap_read(rcg->clkr.regmap, rcg->clkr.enable_reg, &ctl);

        if (banked_mn) {
                regp = &ctl;
                bank_reg = rcg->clkr.enable_reg;
        } else {
                regp = &ns;
                bank_reg = rcg->ns_reg;
        }

        bank = reg_to_bank(rcg, *regp);
        new_bank = enabled ? !bank : bank;

        if (banked_mn) {
                mn = &rcg->mn[new_bank];
                md_reg = rcg->md_reg[new_bank];

                ns |= BIT(mn->mnctr_reset_bit);
                regmap_write(rcg->clkr.regmap, rcg->ns_reg, ns);

                regmap_read(rcg->clkr.regmap, md_reg, &md);
                md = mn_to_md(mn, f->m, f->n, md);
                regmap_write(rcg->clkr.regmap, md_reg, md);

                ns = mn_to_ns(mn, f->m, f->n, ns);
                regmap_write(rcg->clkr.regmap, rcg->ns_reg, ns);

                ctl = mn_to_reg(mn, f->m, f->n, ctl);
                regmap_write(rcg->clkr.regmap, rcg->clkr.enable_reg, ctl);

                ns &= ~BIT(mn->mnctr_reset_bit);
                regmap_write(rcg->clkr.regmap, rcg->ns_reg, ns);
        } else {
                p = &rcg->p[new_bank];
                ns = pre_div_to_ns(p, f->pre_div - 1, ns);
        }

        s = &rcg->s[new_bank];
        ns = src_to_ns(s, s->parent_map[f->src], ns);
        regmap_write(rcg->clkr.regmap, rcg->ns_reg, ns);

        if (enabled) {
                *regp ^= BIT(rcg->mux_sel_bit);
                regmap_write(rcg->clkr.regmap, bank_reg, *regp);
        }
}

static int clk_dyn_rcg_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_dyn_rcg *rcg = to_clk_dyn_rcg(hw);
        u32 ns, ctl, md, reg;
        int bank;
        struct freq_tbl f = { 0 };
        bool banked_mn = !!rcg->mn[1].width;

        regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
        regmap_read(rcg->clkr.regmap, rcg->clkr.enable_reg, &ctl);
        reg = banked_mn ? ctl : ns;

        bank = reg_to_bank(rcg, reg);

        if (banked_mn) {
                regmap_read(rcg->clkr.regmap, rcg->md_reg[bank], &md);
                f.m = md_to_m(&rcg->mn[bank], md);
                f.n = ns_m_to_n(&rcg->mn[bank], ns, f.m);
        } else {
                f.pre_div = ns_to_pre_div(&rcg->p[bank], ns) + 1;
        }
        f.src = index;

        configure_bank(rcg, &f);

        return 0;
}

/*
 * Calculate m/n:d rate
 *
 *          parent_rate     m
 *   rate = ----------- x  ---
 *            pre_div       n
 */
static unsigned long
calc_rate(unsigned long rate, u32 m, u32 n, u32 mode, u32 pre_div)
{
        if (pre_div)
                rate /= pre_div + 1;

        if (mode) {
                u64 tmp = rate;
                tmp *= m;
                do_div(tmp, n);
                rate = tmp;
        }

        return rate;
}

static unsigned long
clk_rcg_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
{
        struct clk_rcg *rcg = to_clk_rcg(hw);
        u32 pre_div, m = 0, n = 0, ns, md, mode = 0;
        struct mn *mn = &rcg->mn;

        regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
        pre_div = ns_to_pre_div(&rcg->p, ns);

        if (rcg->mn.width) {
                regmap_read(rcg->clkr.regmap, rcg->md_reg, &md);
                m = md_to_m(mn, md);
                n = ns_m_to_n(mn, ns, m);
                /* MN counter mode is in hw.enable_reg sometimes */
                if (rcg->clkr.enable_reg != rcg->ns_reg)
                        regmap_read(rcg->clkr.regmap, rcg->clkr.enable_reg, &mode);
                else
                        mode = ns;
                mode = reg_to_mnctr_mode(mn, mode);
        }

        return calc_rate(parent_rate, m, n, mode, pre_div);
}

static unsigned long
clk_dyn_rcg_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
{
        struct clk_dyn_rcg *rcg = to_clk_dyn_rcg(hw);
        u32 m, n, pre_div, ns, md, mode, reg;
        int bank;
        struct mn *mn;
        bool banked_mn = !!rcg->mn[1].width;

        regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);

        if (banked_mn)
                regmap_read(rcg->clkr.regmap, rcg->clkr.enable_reg, &reg);
        else
                reg = ns;

        bank = reg_to_bank(rcg, reg);

        if (banked_mn) {
                mn = &rcg->mn[bank];
                regmap_read(rcg->clkr.regmap, rcg->md_reg[bank], &md);
                m = md_to_m(mn, md);
                n = ns_m_to_n(mn, ns, m);
                mode = reg_to_mnctr_mode(mn, reg);
                return calc_rate(parent_rate, m, n, mode, 0);
        } else {
                pre_div = ns_to_pre_div(&rcg->p[bank], ns);
                return calc_rate(parent_rate, 0, 0, 0, pre_div);
        }
}

static const
struct freq_tbl *find_freq(const struct freq_tbl *f, unsigned long rate)
{
        if (!f)
                return NULL;

        for (; f->freq; f++)
                if (rate <= f->freq)
                        return f;

        return NULL;
}

static long _freq_tbl_determine_rate(struct clk_hw *hw,
                const struct freq_tbl *f, unsigned long rate,
                unsigned long *p_rate, struct clk **p)
{
        unsigned long clk_flags;

        f = find_freq(f, rate);
        if (!f)
                return -EINVAL;

        clk_flags = __clk_get_flags(hw->clk);
        *p = clk_get_parent_by_index(hw->clk, f->src);
        if (clk_flags & CLK_SET_RATE_PARENT) {
                rate = rate * f->pre_div;
                if (f->n) {
                        u64 tmp = rate;
                        tmp = tmp * f->n;
                        do_div(tmp, f->m);
                        rate = tmp;
                }
        } else {
                rate =  __clk_get_rate(*p);
        }
        *p_rate = rate;

        return f->freq;
}

static long clk_rcg_determine_rate(struct clk_hw *hw, unsigned long rate,
                unsigned long *p_rate, struct clk **p)
{
        struct clk_rcg *rcg = to_clk_rcg(hw);

        return _freq_tbl_determine_rate(hw, rcg->freq_tbl, rate, p_rate, p);
}

static long clk_dyn_rcg_determine_rate(struct clk_hw *hw, unsigned long rate,
                unsigned long *p_rate, struct clk **p)
{
        struct clk_dyn_rcg *rcg = to_clk_dyn_rcg(hw);

        return _freq_tbl_determine_rate(hw, rcg->freq_tbl, rate, p_rate, p);
}

static int clk_rcg_set_rate(struct clk_hw *hw, unsigned long rate,
                            unsigned long parent_rate)
{
        struct clk_rcg *rcg = to_clk_rcg(hw);
        const struct freq_tbl *f;
        u32 ns, md, ctl;
        struct mn *mn = &rcg->mn;
        u32 mask = 0;
        unsigned int reset_reg;

        f = find_freq(rcg->freq_tbl, rate);
        if (!f)
                return -EINVAL;

        if (rcg->mn.reset_in_cc)
                reset_reg = rcg->clkr.enable_reg;
        else
                reset_reg = rcg->ns_reg;

        if (rcg->mn.width) {
                mask = BIT(mn->mnctr_reset_bit);
                regmap_update_bits(rcg->clkr.regmap, reset_reg, mask, mask);

                regmap_read(rcg->clkr.regmap, rcg->md_reg, &md);
                md = mn_to_md(mn, f->m, f->n, md);
                regmap_write(rcg->clkr.regmap, rcg->md_reg, md);

                regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
                /* MN counter mode is in hw.enable_reg sometimes */
                if (rcg->clkr.enable_reg != rcg->ns_reg) {
                        regmap_read(rcg->clkr.regmap, rcg->clkr.enable_reg, &ctl);
                        ctl = mn_to_reg(mn, f->m, f->n, ctl);
                        regmap_write(rcg->clkr.regmap, rcg->clkr.enable_reg, ctl);
                } else {
                        ns = mn_to_reg(mn, f->m, f->n, ns);
                }
                ns = mn_to_ns(mn, f->m, f->n, ns);
        } else {
                regmap_read(rcg->clkr.regmap, rcg->ns_reg, &ns);
        }

        ns = pre_div_to_ns(&rcg->p, f->pre_div - 1, ns);
        regmap_write(rcg->clkr.regmap, rcg->ns_reg, ns);

        regmap_update_bits(rcg->clkr.regmap, reset_reg, mask, 0);

        return 0;
}

static int __clk_dyn_rcg_set_rate(struct clk_hw *hw, unsigned long rate)
{
        struct clk_dyn_rcg *rcg = to_clk_dyn_rcg(hw);
        const struct freq_tbl *f;

        f = find_freq(rcg->freq_tbl, rate);
        if (!f)
                return -EINVAL;

        configure_bank(rcg, f);

        return 0;
}

static int clk_dyn_rcg_set_rate(struct clk_hw *hw, unsigned long rate,
                            unsigned long parent_rate)
{
        return __clk_dyn_rcg_set_rate(hw, rate);
}

static int clk_dyn_rcg_set_rate_and_parent(struct clk_hw *hw,
                unsigned long rate, unsigned long parent_rate, u8 index)
{
        return __clk_dyn_rcg_set_rate(hw, rate);
}

const struct clk_ops clk_rcg_ops = {
        .enable = clk_enable_regmap,
        .disable = clk_disable_regmap,
        .get_parent = clk_rcg_get_parent,
        .set_parent = clk_rcg_set_parent,
        .recalc_rate = clk_rcg_recalc_rate,
        .determine_rate = clk_rcg_determine_rate,
        .set_rate = clk_rcg_set_rate,
};
EXPORT_SYMBOL_GPL(clk_rcg_ops);

const struct clk_ops clk_dyn_rcg_ops = {
        .enable = clk_enable_regmap,
        .is_enabled = clk_is_enabled_regmap,
        .disable = clk_disable_regmap,
        .get_parent = clk_dyn_rcg_get_parent,
        .set_parent = clk_dyn_rcg_set_parent,
        .recalc_rate = clk_dyn_rcg_recalc_rate,
        .determine_rate = clk_dyn_rcg_determine_rate,
        .set_rate = clk_dyn_rcg_set_rate,
        .set_rate_and_parent = clk_dyn_rcg_set_rate_and_parent,
};
EXPORT_SYMBOL_GPL(clk_dyn_rcg_ops);