root/drivers/clk/stm32/clk-stm32-core.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) STMicroelectronics 2022 - All Rights Reserved
 * Author: Gabriel Fernandez <gabriel.fernandez@foss.st.com> for STMicroelectronics.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include "clk-stm32-core.h"
#include "reset-stm32.h"

static DEFINE_SPINLOCK(rlock);

static int stm32_rcc_clock_init(struct device *dev,
                                const struct of_device_id *match,
                                void __iomem *base)
{
        const struct stm32_rcc_match_data *data = match->data;
        struct clk_hw_onecell_data *clk_data = data->hw_clks;
        struct clk_hw **hws;
        int n, max_binding;

        max_binding =  data->maxbinding;

        clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, max_binding), GFP_KERNEL);
        if (!clk_data)
                return -ENOMEM;

        clk_data->num = max_binding;

        hws = clk_data->hws;

        for (n = 0; n < max_binding; n++)
                hws[n] = ERR_PTR(-ENOENT);

        for (n = 0; n < data->num_clocks; n++) {
                const struct clock_config *cfg_clock = &data->tab_clocks[n];
                struct clk_hw *hw = ERR_PTR(-ENOENT);

                if (data->check_security &&
                    data->check_security(dev->of_node, base, cfg_clock))
                        continue;

                if (cfg_clock->func)
                        hw = (*cfg_clock->func)(dev, data, base, &rlock,
                                                cfg_clock);

                if (IS_ERR(hw)) {
                        dev_err(dev, "Can't register clk %d: %ld\n", n,
                                PTR_ERR(hw));
                        return PTR_ERR(hw);
                }

                if (cfg_clock->id != NO_ID)
                        hws[cfg_clock->id] = hw;
        }

        return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, clk_data);
}

int stm32_rcc_init(struct device *dev, const struct of_device_id *match_data,
                   void __iomem *base)
{
        const struct stm32_rcc_match_data *rcc_match_data;
        const struct of_device_id *match;
        int err;

        match = of_match_node(match_data, dev_of_node(dev));
        if (!match) {
                dev_err(dev, "match data not found\n");
                return -ENODEV;
        }

        rcc_match_data = match->data;

        /* RCC Reset Configuration */
        err = stm32_rcc_reset_init(dev, rcc_match_data->reset_data, base);
        if (err) {
                pr_err("stm32 reset failed to initialize\n");
                return err;
        }

        /* RCC Clock Configuration */
        err = stm32_rcc_clock_init(dev, match, base);
        if (err) {
                pr_err("stm32 clock failed to initialize\n");
                return err;
        }

        return 0;
}

static u8 stm32_mux_get_parent(void __iomem *base,
                               struct clk_stm32_clock_data *data,
                               u16 mux_id)
{
        const struct stm32_mux_cfg *mux = &data->muxes[mux_id];
        u32 mask = BIT(mux->width) - 1;
        u32 val;

        val = readl(base + mux->offset) >> mux->shift;
        val &= mask;

        return val;
}

static int stm32_mux_set_parent(void __iomem *base,
                                struct clk_stm32_clock_data *data,
                                u16 mux_id, u8 index)
{
        const struct stm32_mux_cfg *mux = &data->muxes[mux_id];

        u32 mask = BIT(mux->width) - 1;
        u32 reg = readl(base + mux->offset);
        u32 val = index << mux->shift;

        reg &= ~(mask << mux->shift);
        reg |= val;

        writel(reg, base + mux->offset);

        return 0;
}

static void stm32_gate_endisable(void __iomem *base,
                                 struct clk_stm32_clock_data *data,
                                 u16 gate_id, int enable)
{
        const struct stm32_gate_cfg *gate = &data->gates[gate_id];
        void __iomem *addr = base + gate->offset;

        if (enable) {
                if (data->gate_cpt[gate_id]++ > 0)
                        return;

                if (gate->set_clr != 0)
                        writel(BIT(gate->bit_idx), addr);
                else
                        writel(readl(addr) | BIT(gate->bit_idx), addr);
        } else {
                if (--data->gate_cpt[gate_id] > 0)
                        return;

                if (gate->set_clr != 0)
                        writel(BIT(gate->bit_idx), addr + gate->set_clr);
                else
                        writel(readl(addr) & ~BIT(gate->bit_idx), addr);
        }
}

static void stm32_gate_disable_unused(void __iomem *base,
                                      struct clk_stm32_clock_data *data,
                                      u16 gate_id)
{
        const struct stm32_gate_cfg *gate = &data->gates[gate_id];
        void __iomem *addr = base + gate->offset;

        if (data->gate_cpt[gate_id] > 0)
                return;

        if (gate->set_clr != 0)
                writel(BIT(gate->bit_idx), addr + gate->set_clr);
        else
                writel(readl(addr) & ~BIT(gate->bit_idx), addr);
}

static int stm32_gate_is_enabled(void __iomem *base,
                                 struct clk_stm32_clock_data *data,
                                 u16 gate_id)
{
        const struct stm32_gate_cfg *gate = &data->gates[gate_id];

        return (readl(base + gate->offset) & BIT(gate->bit_idx)) != 0;
}

static unsigned int _get_table_div(const struct clk_div_table *table,
                                   unsigned int val)
{
        const struct clk_div_table *clkt;

        for (clkt = table; clkt->div; clkt++)
                if (clkt->val == val)
                        return clkt->div;
        return 0;
}

static unsigned int _get_div(const struct clk_div_table *table,
                             unsigned int val, unsigned long flags, u8 width)
{
        if (flags & CLK_DIVIDER_ONE_BASED)
                return val;
        if (flags & CLK_DIVIDER_POWER_OF_TWO)
                return 1 << val;
        if (table)
                return _get_table_div(table, val);
        return val + 1;
}

static unsigned long stm32_divider_get_rate(void __iomem *base,
                                            struct clk_stm32_clock_data *data,
                                            u16 div_id,
                                            unsigned long parent_rate)
{
        const struct stm32_div_cfg *divider = &data->dividers[div_id];
        unsigned int val;
        unsigned int div;

        val =  readl(base + divider->offset) >> divider->shift;
        val &= clk_div_mask(divider->width);
        div = _get_div(divider->table, val, divider->flags, divider->width);

        if (!div) {
                WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
                     "%d: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
                     div_id);
                return parent_rate;
        }

        return DIV_ROUND_UP_ULL((u64)parent_rate, div);
}

static int stm32_divider_set_rate(void __iomem *base,
                                  struct clk_stm32_clock_data *data,
                                  u16 div_id, unsigned long rate,
                                  unsigned long parent_rate)
{
        const struct stm32_div_cfg *divider = &data->dividers[div_id];
        int value;
        u32 val;

        value = divider_get_val(rate, parent_rate, divider->table,
                                divider->width, divider->flags);
        if (value < 0)
                return value;

        if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
                val = clk_div_mask(divider->width) << (divider->shift + 16);
        } else {
                val = readl(base + divider->offset);
                val &= ~(clk_div_mask(divider->width) << divider->shift);
        }

        val |= (u32)value << divider->shift;

        writel(val, base + divider->offset);

        return 0;
}

static u8 clk_stm32_mux_get_parent(struct clk_hw *hw)
{
        struct clk_stm32_mux *mux = to_clk_stm32_mux(hw);

        return stm32_mux_get_parent(mux->base, mux->clock_data, mux->mux_id);
}

static int clk_stm32_mux_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_stm32_mux *mux = to_clk_stm32_mux(hw);
        unsigned long flags = 0;

        spin_lock_irqsave(mux->lock, flags);

        stm32_mux_set_parent(mux->base, mux->clock_data, mux->mux_id, index);

        spin_unlock_irqrestore(mux->lock, flags);

        return 0;
}

const struct clk_ops clk_stm32_mux_ops = {
        .determine_rate = __clk_mux_determine_rate,
        .get_parent     = clk_stm32_mux_get_parent,
        .set_parent     = clk_stm32_mux_set_parent,
};

static void clk_stm32_gate_endisable(struct clk_hw *hw, int enable)
{
        struct clk_stm32_gate *gate = to_clk_stm32_gate(hw);
        unsigned long flags = 0;

        spin_lock_irqsave(gate->lock, flags);

        stm32_gate_endisable(gate->base, gate->clock_data, gate->gate_id, enable);

        spin_unlock_irqrestore(gate->lock, flags);
}

static int clk_stm32_gate_enable(struct clk_hw *hw)
{
        clk_stm32_gate_endisable(hw, 1);

        return 0;
}

static void clk_stm32_gate_disable(struct clk_hw *hw)
{
        clk_stm32_gate_endisable(hw, 0);
}

static int clk_stm32_gate_is_enabled(struct clk_hw *hw)
{
        struct clk_stm32_gate *gate = to_clk_stm32_gate(hw);

        return stm32_gate_is_enabled(gate->base, gate->clock_data, gate->gate_id);
}

static void clk_stm32_gate_disable_unused(struct clk_hw *hw)
{
        struct clk_stm32_gate *gate = to_clk_stm32_gate(hw);
        unsigned long flags = 0;

        spin_lock_irqsave(gate->lock, flags);

        stm32_gate_disable_unused(gate->base, gate->clock_data, gate->gate_id);

        spin_unlock_irqrestore(gate->lock, flags);
}

const struct clk_ops clk_stm32_gate_ops = {
        .enable         = clk_stm32_gate_enable,
        .disable        = clk_stm32_gate_disable,
        .is_enabled     = clk_stm32_gate_is_enabled,
        .disable_unused = clk_stm32_gate_disable_unused,
};

static int clk_stm32_divider_set_rate(struct clk_hw *hw, unsigned long rate,
                                      unsigned long parent_rate)
{
        struct clk_stm32_div *div = to_clk_stm32_divider(hw);
        unsigned long flags = 0;
        int ret;

        if (div->div_id == NO_STM32_DIV)
                return rate;

        spin_lock_irqsave(div->lock, flags);

        ret = stm32_divider_set_rate(div->base, div->clock_data, div->div_id, rate, parent_rate);

        spin_unlock_irqrestore(div->lock, flags);

        return ret;
}

static int clk_stm32_divider_determine_rate(struct clk_hw *hw,
                                            struct clk_rate_request *req)
{
        struct clk_stm32_div *div = to_clk_stm32_divider(hw);
        const struct stm32_div_cfg *divider;

        if (div->div_id == NO_STM32_DIV)
                return 0;

        divider = &div->clock_data->dividers[div->div_id];

        /* if read only, just return current value */
        if (divider->flags & CLK_DIVIDER_READ_ONLY) {
                u32 val;

                val =  readl(div->base + divider->offset) >> divider->shift;
                val &= clk_div_mask(divider->width);

                return divider_ro_determine_rate(hw, req,
                                                 divider->table,
                                                 divider->width,
                                                 divider->flags, val);
        }

        return divider_determine_rate(hw, req, divider->table, divider->width,
                                      divider->flags);
}

static unsigned long clk_stm32_divider_recalc_rate(struct clk_hw *hw,
                                                   unsigned long parent_rate)
{
        struct clk_stm32_div *div = to_clk_stm32_divider(hw);

        if (div->div_id == NO_STM32_DIV)
                return parent_rate;

        return stm32_divider_get_rate(div->base, div->clock_data, div->div_id, parent_rate);
}

const struct clk_ops clk_stm32_divider_ops = {
        .recalc_rate    = clk_stm32_divider_recalc_rate,
        .determine_rate = clk_stm32_divider_determine_rate,
        .set_rate       = clk_stm32_divider_set_rate,
};

static int clk_stm32_composite_set_rate(struct clk_hw *hw, unsigned long rate,
                                        unsigned long parent_rate)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
        unsigned long flags = 0;
        int ret;

        if (composite->div_id == NO_STM32_DIV)
                return rate;

        spin_lock_irqsave(composite->lock, flags);

        ret = stm32_divider_set_rate(composite->base, composite->clock_data,
                                     composite->div_id, rate, parent_rate);

        spin_unlock_irqrestore(composite->lock, flags);

        return ret;
}

static unsigned long clk_stm32_composite_recalc_rate(struct clk_hw *hw,
                                                     unsigned long parent_rate)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);

        if (composite->div_id == NO_STM32_DIV)
                return parent_rate;

        return stm32_divider_get_rate(composite->base, composite->clock_data,
                                      composite->div_id, parent_rate);
}

static int clk_stm32_composite_determine_rate(struct clk_hw *hw,
                                              struct clk_rate_request *req)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
        const struct stm32_div_cfg *divider;

        if (composite->div_id == NO_STM32_DIV)
                return 0;

        divider = &composite->clock_data->dividers[composite->div_id];

        /* if read only, just return current value */
        if (divider->flags & CLK_DIVIDER_READ_ONLY) {
                u32 val;

                val =  readl(composite->base + divider->offset) >> divider->shift;
                val &= clk_div_mask(divider->width);

                return divider_ro_determine_rate(hw, req, divider->table,
                                                 divider->width, divider->flags,
                                                 val);
        }

        return divider_determine_rate(hw, req, divider->table, divider->width,
                                      divider->flags);
}

static u8 clk_stm32_composite_get_parent(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);

        return stm32_mux_get_parent(composite->base, composite->clock_data, composite->mux_id);
}

static int clk_stm32_composite_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
        unsigned long flags = 0;

        spin_lock_irqsave(composite->lock, flags);

        stm32_mux_set_parent(composite->base, composite->clock_data, composite->mux_id, index);

        spin_unlock_irqrestore(composite->lock, flags);

        if (composite->clock_data->is_multi_mux) {
                struct clk_hw *other_mux_hw = composite->clock_data->is_multi_mux(hw);

                if (other_mux_hw) {
                        struct clk_hw *hwp = clk_hw_get_parent_by_index(hw, index);

                        clk_hw_reparent(other_mux_hw, hwp);
                }
        }

        return 0;
}

static int clk_stm32_composite_is_enabled(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);

        if (composite->gate_id == NO_STM32_GATE)
                return (__clk_get_enable_count(hw->clk) > 0);

        return stm32_gate_is_enabled(composite->base, composite->clock_data, composite->gate_id);
}

#define MUX_SAFE_POSITION 0

static int clk_stm32_has_safe_mux(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
        const struct stm32_mux_cfg *mux = &composite->clock_data->muxes[composite->mux_id];

        return !!(mux->flags & MUX_SAFE);
}

static void clk_stm32_set_safe_position_mux(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);

        if (!clk_stm32_composite_is_enabled(hw)) {
                unsigned long flags = 0;

                if (composite->clock_data->is_multi_mux) {
                        struct clk_hw *other_mux_hw = NULL;

                        other_mux_hw = composite->clock_data->is_multi_mux(hw);

                        if (!other_mux_hw || clk_stm32_composite_is_enabled(other_mux_hw))
                                return;
                }

                spin_lock_irqsave(composite->lock, flags);

                stm32_mux_set_parent(composite->base, composite->clock_data,
                                     composite->mux_id, MUX_SAFE_POSITION);

                spin_unlock_irqrestore(composite->lock, flags);
        }
}

static void clk_stm32_safe_restore_position_mux(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
        int sel = clk_hw_get_parent_index(hw);
        unsigned long flags = 0;

        spin_lock_irqsave(composite->lock, flags);

        stm32_mux_set_parent(composite->base, composite->clock_data, composite->mux_id, sel);

        spin_unlock_irqrestore(composite->lock, flags);
}

static void clk_stm32_composite_gate_endisable(struct clk_hw *hw, int enable)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
        unsigned long flags = 0;

        spin_lock_irqsave(composite->lock, flags);

        stm32_gate_endisable(composite->base, composite->clock_data, composite->gate_id, enable);

        spin_unlock_irqrestore(composite->lock, flags);
}

static int clk_stm32_composite_gate_enable(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);

        if (composite->gate_id == NO_STM32_GATE)
                return 0;

        clk_stm32_composite_gate_endisable(hw, 1);

        if (composite->mux_id != NO_STM32_MUX && clk_stm32_has_safe_mux(hw))
                clk_stm32_safe_restore_position_mux(hw);

        return 0;
}

static void clk_stm32_composite_gate_disable(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);

        if (composite->gate_id == NO_STM32_GATE)
                return;

        clk_stm32_composite_gate_endisable(hw, 0);

        if (composite->mux_id != NO_STM32_MUX && clk_stm32_has_safe_mux(hw))
                clk_stm32_set_safe_position_mux(hw);
}

static void clk_stm32_composite_disable_unused(struct clk_hw *hw)
{
        struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
        unsigned long flags = 0;

        if (composite->gate_id == NO_STM32_GATE)
                return;

        spin_lock_irqsave(composite->lock, flags);

        stm32_gate_disable_unused(composite->base, composite->clock_data, composite->gate_id);

        spin_unlock_irqrestore(composite->lock, flags);
}

const struct clk_ops clk_stm32_composite_ops = {
        .set_rate       = clk_stm32_composite_set_rate,
        .recalc_rate    = clk_stm32_composite_recalc_rate,
        .determine_rate = clk_stm32_composite_determine_rate,
        .get_parent     = clk_stm32_composite_get_parent,
        .set_parent     = clk_stm32_composite_set_parent,
        .enable         = clk_stm32_composite_gate_enable,
        .disable        = clk_stm32_composite_gate_disable,
        .is_enabled     = clk_stm32_composite_is_enabled,
        .disable_unused = clk_stm32_composite_disable_unused,
};

struct clk_hw *clk_stm32_mux_register(struct device *dev,
                                      const struct stm32_rcc_match_data *data,
                                      void __iomem *base,
                                      spinlock_t *lock,
                                      const struct clock_config *cfg)
{
        struct clk_stm32_mux *mux = cfg->clock_cfg;
        struct clk_hw *hw = &mux->hw;
        int err;

        mux->base = base;
        mux->lock = lock;
        mux->clock_data = data->clock_data;

        err = devm_clk_hw_register(dev, hw);
        if (err)
                return ERR_PTR(err);

        return hw;
}

struct clk_hw *clk_stm32_gate_register(struct device *dev,
                                       const struct stm32_rcc_match_data *data,
                                       void __iomem *base,
                                       spinlock_t *lock,
                                       const struct clock_config *cfg)
{
        struct clk_stm32_gate *gate = cfg->clock_cfg;
        struct clk_hw *hw = &gate->hw;
        int err;

        gate->base = base;
        gate->lock = lock;
        gate->clock_data = data->clock_data;

        err = devm_clk_hw_register(dev, hw);
        if (err)
                return ERR_PTR(err);

        return hw;
}

struct clk_hw *clk_stm32_div_register(struct device *dev,
                                      const struct stm32_rcc_match_data *data,
                                      void __iomem *base,
                                      spinlock_t *lock,
                                      const struct clock_config *cfg)
{
        struct clk_stm32_div *div = cfg->clock_cfg;
        struct clk_hw *hw = &div->hw;
        int err;

        div->base = base;
        div->lock = lock;
        div->clock_data = data->clock_data;

        err = devm_clk_hw_register(dev, hw);
        if (err)
                return ERR_PTR(err);

        return hw;
}

struct clk_hw *clk_stm32_composite_register(struct device *dev,
                                            const struct stm32_rcc_match_data *data,
                                            void __iomem *base,
                                            spinlock_t *lock,
                                            const struct clock_config *cfg)
{
        struct clk_stm32_composite *composite = cfg->clock_cfg;
        struct clk_hw *hw = &composite->hw;
        int err;

        composite->base = base;
        composite->lock = lock;
        composite->clock_data = data->clock_data;

        err = devm_clk_hw_register(dev, hw);
        if (err)
                return ERR_PTR(err);

        return hw;
}