root/drivers/clk/sunxi-ng/ccu_nkm.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2016 Maxime Ripard
 * Maxime Ripard <maxime.ripard@free-electrons.com>
 */

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

#include "ccu_gate.h"
#include "ccu_nkm.h"

struct _ccu_nkm {
        unsigned long   n, min_n, max_n;
        unsigned long   k, min_k, max_k;
        unsigned long   m, min_m, max_m;
};

static bool ccu_nkm_is_valid_rate(struct ccu_common *common, unsigned long parent,
                                  unsigned long n, unsigned long m)
{
        struct ccu_nkm *nkm = container_of(common, struct ccu_nkm, common);

        if (nkm->max_m_n_ratio && (m > nkm->max_m_n_ratio * n))
                return false;

        if (nkm->min_parent_m_ratio && (parent < nkm->min_parent_m_ratio * m))
                return false;

        return true;
}

static unsigned long ccu_nkm_find_best_with_parent_adj(struct ccu_common *common,
                                                       struct clk_hw *parent_hw,
                                                       unsigned long *parent, unsigned long rate,
                                                       struct _ccu_nkm *nkm)
{
        unsigned long best_rate = 0, best_parent_rate = *parent;
        unsigned long best_n = 0, best_k = 0, best_m = 0;
        unsigned long _n, _k, _m;

        for (_k = nkm->min_k; _k <= nkm->max_k; _k++) {
                for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
                        for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
                                unsigned long tmp_rate, tmp_parent;

                                tmp_parent = clk_hw_round_rate(parent_hw, rate * _m / (_n * _k));

                                if (!ccu_nkm_is_valid_rate(common, tmp_parent, _n, _m))
                                        continue;

                                tmp_rate = tmp_parent * _n * _k / _m;

                                if (ccu_is_better_rate(common, rate, tmp_rate, best_rate) ||
                                    (tmp_parent == *parent && tmp_rate == best_rate)) {
                                        best_rate = tmp_rate;
                                        best_parent_rate = tmp_parent;
                                        best_n = _n;
                                        best_k = _k;
                                        best_m = _m;
                                }
                        }
                }
        }

        nkm->n = best_n;
        nkm->k = best_k;
        nkm->m = best_m;

        *parent = best_parent_rate;

        return best_rate;
}

static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
                                       struct _ccu_nkm *nkm, struct ccu_common *common)
{
        unsigned long best_rate = 0;
        unsigned long best_n = 0, best_k = 0, best_m = 0;
        unsigned long _n, _k, _m;

        for (_k = nkm->min_k; _k <= nkm->max_k; _k++) {
                for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
                        for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
                                if (!ccu_nkm_is_valid_rate(common, parent, _n, _m))
                                        continue;

                                unsigned long tmp_rate;

                                tmp_rate = parent * _n * _k / _m;

                                if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
                                        best_rate = tmp_rate;
                                        best_n = _n;
                                        best_k = _k;
                                        best_m = _m;
                                }
                        }
                }
        }

        nkm->n = best_n;
        nkm->k = best_k;
        nkm->m = best_m;

        return best_rate;
}

static void ccu_nkm_disable(struct clk_hw *hw)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);

        return ccu_gate_helper_disable(&nkm->common, nkm->enable);
}

static int ccu_nkm_enable(struct clk_hw *hw)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);

        return ccu_gate_helper_enable(&nkm->common, nkm->enable);
}

static int ccu_nkm_is_enabled(struct clk_hw *hw)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);

        return ccu_gate_helper_is_enabled(&nkm->common, nkm->enable);
}

static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
                                        unsigned long parent_rate)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
        unsigned long n, m, k, rate;
        u32 reg;

        reg = readl(nkm->common.base + nkm->common.reg);

        n = reg >> nkm->n.shift;
        n &= (1 << nkm->n.width) - 1;
        n += nkm->n.offset;
        if (!n)
                n++;

        k = reg >> nkm->k.shift;
        k &= (1 << nkm->k.width) - 1;
        k += nkm->k.offset;
        if (!k)
                k++;

        m = reg >> nkm->m.shift;
        m &= (1 << nkm->m.width) - 1;
        m += nkm->m.offset;
        if (!m)
                m++;

        rate = parent_rate * n  * k / m;

        if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
                rate /= nkm->fixed_post_div;

        return rate;
}

static int ccu_nkm_determine_rate_helper(struct ccu_mux_internal *mux,
                                         struct clk_rate_request *req,
                                         void *data)
{
        struct ccu_nkm *nkm = data;
        struct _ccu_nkm _nkm;

        _nkm.min_n = nkm->n.min ?: 1;
        _nkm.max_n = nkm->n.max ?: 1 << nkm->n.width;
        _nkm.min_k = nkm->k.min ?: 1;
        _nkm.max_k = nkm->k.max ?: 1 << nkm->k.width;
        _nkm.min_m = 1;
        _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;

        if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
                req->rate *= nkm->fixed_post_div;

        if (!clk_hw_can_set_rate_parent(&nkm->common.hw))
                req->rate = ccu_nkm_find_best(req->best_parent_rate, req->rate,
                                              &_nkm, &nkm->common);
        else
                req->rate = ccu_nkm_find_best_with_parent_adj(&nkm->common,
                                                              req->best_parent_hw,
                                                              &req->best_parent_rate,
                                                              req->rate, &_nkm);

        if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
                req->rate /= nkm->fixed_post_div;

        return 0;
}

static int ccu_nkm_determine_rate(struct clk_hw *hw,
                                  struct clk_rate_request *req)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);

        return ccu_mux_helper_determine_rate(&nkm->common, &nkm->mux,
                                             req, ccu_nkm_determine_rate_helper, nkm);
}

static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
                           unsigned long parent_rate)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
        struct _ccu_nkm _nkm;
        unsigned long flags;
        u32 reg;

        if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
                rate *= nkm->fixed_post_div;

        _nkm.min_n = nkm->n.min ?: 1;
        _nkm.max_n = nkm->n.max ?: 1 << nkm->n.width;
        _nkm.min_k = nkm->k.min ?: 1;
        _nkm.max_k = nkm->k.max ?: 1 << nkm->k.width;
        _nkm.min_m = 1;
        _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;

        ccu_nkm_find_best(parent_rate, rate, &_nkm, &nkm->common);

        spin_lock_irqsave(nkm->common.lock, flags);

        reg = readl(nkm->common.base + nkm->common.reg);
        reg &= ~GENMASK(nkm->n.width + nkm->n.shift - 1, nkm->n.shift);
        reg &= ~GENMASK(nkm->k.width + nkm->k.shift - 1, nkm->k.shift);
        reg &= ~GENMASK(nkm->m.width + nkm->m.shift - 1, nkm->m.shift);

        reg |= (_nkm.n - nkm->n.offset) << nkm->n.shift;
        reg |= (_nkm.k - nkm->k.offset) << nkm->k.shift;
        reg |= (_nkm.m - nkm->m.offset) << nkm->m.shift;
        writel(reg, nkm->common.base + nkm->common.reg);

        spin_unlock_irqrestore(nkm->common.lock, flags);

        ccu_helper_wait_for_lock(&nkm->common, nkm->lock);

        return 0;
}

static u8 ccu_nkm_get_parent(struct clk_hw *hw)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);

        return ccu_mux_helper_get_parent(&nkm->common, &nkm->mux);
}

static int ccu_nkm_set_parent(struct clk_hw *hw, u8 index)
{
        struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);

        return ccu_mux_helper_set_parent(&nkm->common, &nkm->mux, index);
}

const struct clk_ops ccu_nkm_ops = {
        .disable        = ccu_nkm_disable,
        .enable         = ccu_nkm_enable,
        .is_enabled     = ccu_nkm_is_enabled,

        .get_parent     = ccu_nkm_get_parent,
        .set_parent     = ccu_nkm_set_parent,

        .determine_rate = ccu_nkm_determine_rate,
        .recalc_rate    = ccu_nkm_recalc_rate,
        .set_rate       = ccu_nkm_set_rate,
};
EXPORT_SYMBOL_NS_GPL(ccu_nkm_ops, "SUNXI_CCU");