root/drivers/clk/clk-loongson1.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Clock driver for Loongson-1 SoC
 *
 * Copyright (C) 2012-2023 Keguang Zhang <keguang.zhang@gmail.com>
 */

#include <linux/bits.h>
#include <linux/clk-provider.h>
#include <linux/container_of.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/printk.h>

#include <dt-bindings/clock/loongson,ls1x-clk.h>

/* Loongson 1 Clock Register Definitions */
#define CLK_PLL_FREQ            0x0
#define CLK_PLL_DIV             0x4

static DEFINE_SPINLOCK(ls1x_clk_div_lock);

struct ls1x_clk_pll_data {
        u32 fixed;
        u8 shift;
        u8 int_shift;
        u8 int_width;
        u8 frac_shift;
        u8 frac_width;
};

struct ls1x_clk_div_data {
        u8 shift;
        u8 width;
        unsigned long flags;
        const struct clk_div_table *table;
        u8 bypass_shift;
        u8 bypass_inv;
        spinlock_t *lock;       /* protect access to DIV registers */
};

struct ls1x_clk {
        void __iomem *reg;
        unsigned int offset;
        struct clk_hw hw;
        const void *data;
};

#define to_ls1x_clk(_hw) container_of(_hw, struct ls1x_clk, hw)

static inline unsigned long ls1x_pll_rate_part(unsigned int val,
                                               unsigned int shift,
                                               unsigned int width)
{
        return (val & GENMASK(shift + width, shift)) >> shift;
}

static unsigned long ls1x_pll_recalc_rate(struct clk_hw *hw,
                                          unsigned long parent_rate)
{
        struct ls1x_clk *ls1x_clk = to_ls1x_clk(hw);
        const struct ls1x_clk_pll_data *d = ls1x_clk->data;
        u32 val, rate;

        val = readl(ls1x_clk->reg);
        rate = d->fixed;
        rate += ls1x_pll_rate_part(val, d->int_shift, d->int_width);
        if (d->frac_width)
                rate += ls1x_pll_rate_part(val, d->frac_shift, d->frac_width);
        rate *= parent_rate;
        rate >>= d->shift;

        return rate;
}

static const struct clk_ops ls1x_pll_clk_ops = {
        .recalc_rate = ls1x_pll_recalc_rate,
};

static unsigned long ls1x_divider_recalc_rate(struct clk_hw *hw,
                                              unsigned long parent_rate)
{
        struct ls1x_clk *ls1x_clk = to_ls1x_clk(hw);
        const struct ls1x_clk_div_data *d = ls1x_clk->data;
        unsigned int val;

        val = readl(ls1x_clk->reg) >> d->shift;
        val &= clk_div_mask(d->width);

        return divider_recalc_rate(hw, parent_rate, val, d->table,
                                   d->flags, d->width);
}

static int ls1x_divider_determine_rate(struct clk_hw *hw,
                                       struct clk_rate_request *req)
{
        struct ls1x_clk *ls1x_clk = to_ls1x_clk(hw);
        const struct ls1x_clk_div_data *d = ls1x_clk->data;

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

static int ls1x_divider_set_rate(struct clk_hw *hw, unsigned long rate,
                                 unsigned long parent_rate)
{
        struct ls1x_clk *ls1x_clk = to_ls1x_clk(hw);
        const struct ls1x_clk_div_data *d = ls1x_clk->data;
        int val, div_val;
        unsigned long flags = 0;

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

        spin_lock_irqsave(d->lock, flags);

        /* Bypass the clock */
        val = readl(ls1x_clk->reg);
        if (d->bypass_inv)
                val &= ~BIT(d->bypass_shift);
        else
                val |= BIT(d->bypass_shift);
        writel(val, ls1x_clk->reg);

        val = readl(ls1x_clk->reg);
        val &= ~(clk_div_mask(d->width) << d->shift);
        val |= (u32)div_val << d->shift;
        writel(val, ls1x_clk->reg);

        /* Restore the clock */
        val = readl(ls1x_clk->reg);
        if (d->bypass_inv)
                val |= BIT(d->bypass_shift);
        else
                val &= ~BIT(d->bypass_shift);
        writel(val, ls1x_clk->reg);

        spin_unlock_irqrestore(d->lock, flags);

        return 0;
}

static const struct clk_ops ls1x_clk_divider_ops = {
        .recalc_rate = ls1x_divider_recalc_rate,
        .determine_rate = ls1x_divider_determine_rate,
        .set_rate = ls1x_divider_set_rate,
};

#define LS1X_CLK_PLL(_name, _offset, _fixed, _shift,                    \
                     f_shift, f_width, i_shift, i_width)                \
struct ls1x_clk _name = {                                               \
        .offset = (_offset),                                            \
        .data = &(const struct ls1x_clk_pll_data) {                     \
                .fixed = (_fixed),                                      \
                .shift = (_shift),                                      \
                .int_shift = (i_shift),                                 \
                .int_width = (i_width),                                 \
                .frac_shift = (f_shift),                                \
                .frac_width = (f_width),                                \
        },                                                              \
        .hw.init = &(const struct clk_init_data) {                      \
                .name = #_name,                                         \
                .ops = &ls1x_pll_clk_ops,                               \
                .parent_data = &(const struct clk_parent_data) {        \
                        .fw_name = "xtal",                              \
                        .name = "xtal",                                 \
                        .index = -1,                                    \
                },                                                      \
                .num_parents = 1,                                       \
        },                                                              \
}

#define LS1X_CLK_DIV(_name, _pname, _offset, _shift, _width,            \
                     _table, _bypass_shift, _bypass_inv, _flags)        \
struct ls1x_clk _name = {                                               \
        .offset = (_offset),                                            \
        .data = &(const struct ls1x_clk_div_data){                      \
                .shift = (_shift),                                      \
                .width = (_width),                                      \
                .table = (_table),                                      \
                .flags = (_flags),                                      \
                .bypass_shift = (_bypass_shift),                        \
                .bypass_inv = (_bypass_inv),                            \
                .lock = &ls1x_clk_div_lock,                             \
        },                                                              \
        .hw.init = &(const struct clk_init_data) {                      \
                .name = #_name,                                         \
                .ops = &ls1x_clk_divider_ops,                           \
                .parent_hws = (const struct clk_hw *[]) { _pname },     \
                .num_parents = 1,                                       \
                .flags = CLK_GET_RATE_NOCACHE,                          \
        },                                                              \
}

static LS1X_CLK_PLL(ls1b_clk_pll, CLK_PLL_FREQ, 12, 1, 0, 5, 0, 0);
static LS1X_CLK_DIV(ls1b_clk_cpu, &ls1b_clk_pll.hw, CLK_PLL_DIV,
                    20, 4, NULL, 8, 0,
                    CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ROUND_CLOSEST);
static LS1X_CLK_DIV(ls1b_clk_dc, &ls1b_clk_pll.hw, CLK_PLL_DIV,
                    26, 4, NULL, 12, 0, CLK_DIVIDER_ONE_BASED);
static LS1X_CLK_DIV(ls1b_clk_ahb, &ls1b_clk_pll.hw, CLK_PLL_DIV,
                    14, 4, NULL, 10, 0, CLK_DIVIDER_ONE_BASED);
static CLK_FIXED_FACTOR(ls1b_clk_apb, "ls1b_clk_apb", "ls1b_clk_ahb", 2, 1,
                        CLK_SET_RATE_PARENT);

static struct clk_hw_onecell_data ls1b_clk_hw_data = {
        .hws = {
                [LS1X_CLKID_PLL] = &ls1b_clk_pll.hw,
                [LS1X_CLKID_CPU] = &ls1b_clk_cpu.hw,
                [LS1X_CLKID_DC] = &ls1b_clk_dc.hw,
                [LS1X_CLKID_AHB] = &ls1b_clk_ahb.hw,
                [LS1X_CLKID_APB] = &ls1b_clk_apb.hw,
        },
        .num = CLK_NR_CLKS,
};

static const struct clk_div_table ls1c_ahb_div_table[] = {
        [0] = { .val = 0, .div = 2 },
        [1] = { .val = 1, .div = 4 },
        [2] = { .val = 2, .div = 3 },
        [3] = { .val = 3, .div = 3 },
        [4] = { /* sentinel */ }
};

static LS1X_CLK_PLL(ls1c_clk_pll, CLK_PLL_FREQ, 0, 2, 8, 8, 16, 8);
static LS1X_CLK_DIV(ls1c_clk_cpu, &ls1c_clk_pll.hw, CLK_PLL_DIV,
                    8, 7, NULL, 0, 1,
                    CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ROUND_CLOSEST);
static LS1X_CLK_DIV(ls1c_clk_dc, &ls1c_clk_pll.hw, CLK_PLL_DIV,
                    24, 7, NULL, 4, 1, CLK_DIVIDER_ONE_BASED);
static LS1X_CLK_DIV(ls1c_clk_ahb, &ls1c_clk_cpu.hw, CLK_PLL_FREQ,
                    0, 2, ls1c_ahb_div_table, 0, 0, CLK_DIVIDER_ALLOW_ZERO);
static CLK_FIXED_FACTOR(ls1c_clk_apb, "ls1c_clk_apb", "ls1c_clk_ahb", 1, 1,
                        CLK_SET_RATE_PARENT);

static struct clk_hw_onecell_data ls1c_clk_hw_data = {
        .hws = {
                [LS1X_CLKID_PLL] = &ls1c_clk_pll.hw,
                [LS1X_CLKID_CPU] = &ls1c_clk_cpu.hw,
                [LS1X_CLKID_DC] = &ls1c_clk_dc.hw,
                [LS1X_CLKID_AHB] = &ls1c_clk_ahb.hw,
                [LS1X_CLKID_APB] = &ls1c_clk_apb.hw,
        },
        .num = CLK_NR_CLKS,
};

static void __init ls1x_clk_init(struct device_node *np,
                                 struct clk_hw_onecell_data *hw_data)
{
        struct ls1x_clk *ls1x_clk;
        void __iomem *reg;
        int i, ret;

        reg = of_iomap(np, 0);
        if (!reg) {
                pr_err("Unable to map base for %pOF\n", np);
                return;
        }

        for (i = 0; i < hw_data->num; i++) {
                /* array might be sparse */
                if (!hw_data->hws[i])
                        continue;

                if (i != LS1X_CLKID_APB) {
                        ls1x_clk = to_ls1x_clk(hw_data->hws[i]);
                        ls1x_clk->reg = reg + ls1x_clk->offset;
                }

                ret = of_clk_hw_register(np, hw_data->hws[i]);
                if (ret)
                        goto err;
        }

        ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, hw_data);
        if (!ret)
                return;

err:
        pr_err("Failed to register %pOF\n", np);

        while (--i >= 0)
                clk_hw_unregister(hw_data->hws[i]);

        iounmap(reg);
}

static void __init ls1b_clk_init(struct device_node *np)
{
        return ls1x_clk_init(np, &ls1b_clk_hw_data);
}

static void __init ls1c_clk_init(struct device_node *np)
{
        return ls1x_clk_init(np, &ls1c_clk_hw_data);
}

CLK_OF_DECLARE(ls1b_clk, "loongson,ls1b-clk", ls1b_clk_init);
CLK_OF_DECLARE(ls1c_clk, "loongson,ls1c-clk", ls1c_clk_init);