/*
 * Copyright (c) 2013 Samsung Electronics Co., Ltd.
 * Copyright (c) 2013 Linaro Ltd.
 * Author: Thomas Abraham <thomas.ab@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This file includes utility functions to register clocks to common
 * clock framework for Samsung platforms.
*/

#include <linux/of_address.h>
#include <linux/syscore_ops.h>

#include "clk.h"

static LIST_HEAD(clock_reg_cache_list);

void samsung_clk_save(void __iomem *base,
                                    struct samsung_clk_reg_dump *rd,
                                    unsigned int num_regs)
{
        for (; num_regs > 0; --num_regs, ++rd)
                rd->value = readl(base + rd->offset);
}

void samsung_clk_restore(void __iomem *base,
                                      const struct samsung_clk_reg_dump *rd,
                                      unsigned int num_regs)
{
        for (; num_regs > 0; --num_regs, ++rd)
                writel(rd->value, base + rd->offset);
}

struct samsung_clk_reg_dump *samsung_clk_alloc_reg_dump(
                                                const unsigned long *rdump,
                                                unsigned long nr_rdump)
{
        struct samsung_clk_reg_dump *rd;
        unsigned int i;

        rd = kcalloc(nr_rdump, sizeof(*rd), GFP_KERNEL);
        if (!rd)
                return NULL;

        for (i = 0; i < nr_rdump; ++i)
                rd[i].offset = rdump[i];

        return rd;
}

/* setup the essentials required to support clock lookup using ccf */
struct samsung_clk_provider *__init samsung_clk_init(struct device_node *np,
                        void __iomem *base, unsigned long nr_clks)
{
        struct samsung_clk_provider *ctx;
        struct clk **clk_table;
        int i;

        ctx = kzalloc(sizeof(struct samsung_clk_provider), GFP_KERNEL);
        if (!ctx)
                panic("could not allocate clock provider context.\n");

        clk_table = kcalloc(nr_clks, sizeof(struct clk *), GFP_KERNEL);
        if (!clk_table)
                panic("could not allocate clock lookup table\n");

        for (i = 0; i < nr_clks; ++i)
                clk_table[i] = ERR_PTR(-ENOENT);

        ctx->reg_base = base;
        ctx->clk_data.clks = clk_table;
        ctx->clk_data.clk_num = nr_clks;
        spin_lock_init(&ctx->lock);

        return ctx;
}

void __init samsung_clk_of_add_provider(struct device_node *np,
                                struct samsung_clk_provider *ctx)
{
        if (np) {
                if (of_clk_add_provider(np, of_clk_src_onecell_get,
                                        &ctx->clk_data))
                        panic("could not register clk provider\n");
        }
}

/* add a clock instance to the clock lookup table used for dt based lookup */
void samsung_clk_add_lookup(struct samsung_clk_provider *ctx, struct clk *clk,
                                unsigned int id)
{
        if (ctx->clk_data.clks && id)
                ctx->clk_data.clks[id] = clk;
}

/* register a list of aliases */
void __init samsung_clk_register_alias(struct samsung_clk_provider *ctx,
                                struct samsung_clock_alias *list,
                                unsigned int nr_clk)
{
        struct clk *clk;
        unsigned int idx, ret;

        if (!ctx->clk_data.clks) {
                pr_err("%s: clock table missing\n", __func__);
                return;
        }

        for (idx = 0; idx < nr_clk; idx++, list++) {
                if (!list->id) {
                        pr_err("%s: clock id missing for index %d\n", __func__,
                                idx);
                        continue;
                }

                clk = ctx->clk_data.clks[list->id];
                if (!clk) {
                        pr_err("%s: failed to find clock %d\n", __func__,
                                list->id);
                        continue;
                }

                ret = clk_register_clkdev(clk, list->alias, list->dev_name);
                if (ret)
                        pr_err("%s: failed to register lookup %s\n",
                                        __func__, list->alias);
        }
}

/* register a list of fixed clocks */
void __init samsung_clk_register_fixed_rate(struct samsung_clk_provider *ctx,
                struct samsung_fixed_rate_clock *list, unsigned int nr_clk)
{
        struct clk *clk;
        unsigned int idx, ret;

        for (idx = 0; idx < nr_clk; idx++, list++) {
                clk = clk_register_fixed_rate(NULL, list->name,
                        list->parent_name, list->flags, list->fixed_rate);
                if (IS_ERR(clk)) {
                        pr_err("%s: failed to register clock %s\n", __func__,
                                list->name);
                        continue;
                }

                samsung_clk_add_lookup(ctx, clk, list->id);

                /*
                 * Unconditionally add a clock lookup for the fixed rate clocks.
                 * There are not many of these on any of Samsung platforms.
                 */
                ret = clk_register_clkdev(clk, list->name, NULL);
                if (ret)
                        pr_err("%s: failed to register clock lookup for %s",
                                __func__, list->name);
        }
}

/* register a list of fixed factor clocks */
void __init samsung_clk_register_fixed_factor(struct samsung_clk_provider *ctx,
                struct samsung_fixed_factor_clock *list, unsigned int nr_clk)
{
        struct clk *clk;
        unsigned int idx;

        for (idx = 0; idx < nr_clk; idx++, list++) {
                clk = clk_register_fixed_factor(NULL, list->name,
                        list->parent_name, list->flags, list->mult, list->div);
                if (IS_ERR(clk)) {
                        pr_err("%s: failed to register clock %s\n", __func__,
                                list->name);
                        continue;
                }

                samsung_clk_add_lookup(ctx, clk, list->id);
        }
}

/* register a list of mux clocks */
void __init samsung_clk_register_mux(struct samsung_clk_provider *ctx,
                                struct samsung_mux_clock *list,
                                unsigned int nr_clk)
{
        struct clk *clk;
        unsigned int idx, ret;

        for (idx = 0; idx < nr_clk; idx++, list++) {
                clk = clk_register_mux(NULL, list->name, list->parent_names,
                        list->num_parents, list->flags,
                        ctx->reg_base + list->offset,
                        list->shift, list->width, list->mux_flags, &ctx->lock);
                if (IS_ERR(clk)) {
                        pr_err("%s: failed to register clock %s\n", __func__,
                                list->name);
                        continue;
                }

                samsung_clk_add_lookup(ctx, clk, list->id);

                /* register a clock lookup only if a clock alias is specified */
                if (list->alias) {
                        ret = clk_register_clkdev(clk, list->alias,
                                                list->dev_name);
                        if (ret)
                                pr_err("%s: failed to register lookup %s\n",
                                                __func__, list->alias);
                }
        }
}

/* register a list of div clocks */
void __init samsung_clk_register_div(struct samsung_clk_provider *ctx,
                                struct samsung_div_clock *list,
                                unsigned int nr_clk)
{
        struct clk *clk;
        unsigned int idx, ret;

        for (idx = 0; idx < nr_clk; idx++, list++) {
                if (list->table)
                        clk = clk_register_divider_table(NULL, list->name,
                                list->parent_name, list->flags,
                                ctx->reg_base + list->offset,
                                list->shift, list->width, list->div_flags,
                                list->table, &ctx->lock);
                else
                        clk = clk_register_divider(NULL, list->name,
                                list->parent_name, list->flags,
                                ctx->reg_base + list->offset, list->shift,
                                list->width, list->div_flags, &ctx->lock);
                if (IS_ERR(clk)) {
                        pr_err("%s: failed to register clock %s\n", __func__,
                                list->name);
                        continue;
                }

                samsung_clk_add_lookup(ctx, clk, list->id);

                /* register a clock lookup only if a clock alias is specified */
                if (list->alias) {
                        ret = clk_register_clkdev(clk, list->alias,
                                                list->dev_name);
                        if (ret)
                                pr_err("%s: failed to register lookup %s\n",
                                                __func__, list->alias);
                }
        }
}

/* register a list of gate clocks */
void __init samsung_clk_register_gate(struct samsung_clk_provider *ctx,
                                struct samsung_gate_clock *list,
                                unsigned int nr_clk)
{
        struct clk *clk;
        unsigned int idx, ret;

        for (idx = 0; idx < nr_clk; idx++, list++) {
                clk = clk_register_gate(NULL, list->name, list->parent_name,
                                list->flags, ctx->reg_base + list->offset,
                                list->bit_idx, list->gate_flags, &ctx->lock);
                if (IS_ERR(clk)) {
                        pr_err("%s: failed to register clock %s\n", __func__,
                                list->name);
                        continue;
                }

                /* register a clock lookup only if a clock alias is specified */
                if (list->alias) {
                        ret = clk_register_clkdev(clk, list->alias,
                                                        list->dev_name);
                        if (ret)
                                pr_err("%s: failed to register lookup %s\n",
                                        __func__, list->alias);
                }

                samsung_clk_add_lookup(ctx, clk, list->id);
        }
}

/*
 * obtain the clock speed of all external fixed clock sources from device
 * tree and register it
 */
void __init samsung_clk_of_register_fixed_ext(struct samsung_clk_provider *ctx,
                        struct samsung_fixed_rate_clock *fixed_rate_clk,
                        unsigned int nr_fixed_rate_clk,
                        const struct of_device_id *clk_matches)
{
        const struct of_device_id *match;
        struct device_node *clk_np;
        u32 freq;

        for_each_matching_node_and_match(clk_np, clk_matches, &match) {
                if (of_property_read_u32(clk_np, "clock-frequency", &freq))
                        continue;
                fixed_rate_clk[(unsigned long)match->data].fixed_rate = freq;
        }
        samsung_clk_register_fixed_rate(ctx, fixed_rate_clk, nr_fixed_rate_clk);
}

/* utility function to get the rate of a specified clock */
unsigned long _get_rate(const char *clk_name)
{
        struct clk *clk;

        clk = __clk_lookup(clk_name);
        if (!clk) {
                pr_err("%s: could not find clock %s\n", __func__, clk_name);
                return 0;
        }

        return clk_get_rate(clk);
}

#ifdef CONFIG_PM_SLEEP
static int samsung_clk_suspend(void)
{
        struct samsung_clock_reg_cache *reg_cache;

        list_for_each_entry(reg_cache, &clock_reg_cache_list, node)
                samsung_clk_save(reg_cache->reg_base, reg_cache->rdump,
                                reg_cache->rd_num);
        return 0;
}

static void samsung_clk_resume(void)
{
        struct samsung_clock_reg_cache *reg_cache;

        list_for_each_entry(reg_cache, &clock_reg_cache_list, node)
                samsung_clk_restore(reg_cache->reg_base, reg_cache->rdump,
                                reg_cache->rd_num);
}

static struct syscore_ops samsung_clk_syscore_ops = {
        .suspend = samsung_clk_suspend,
        .resume = samsung_clk_resume,
};

static void samsung_clk_sleep_init(void __iomem *reg_base,
                const unsigned long *rdump,
                unsigned long nr_rdump)
{
        struct samsung_clock_reg_cache *reg_cache;

        reg_cache = kzalloc(sizeof(struct samsung_clock_reg_cache),
                        GFP_KERNEL);
        if (!reg_cache)
                panic("could not allocate register reg_cache.\n");
        reg_cache->rdump = samsung_clk_alloc_reg_dump(rdump, nr_rdump);

        if (!reg_cache->rdump)
                panic("could not allocate register dump storage.\n");

        if (list_empty(&clock_reg_cache_list))
                register_syscore_ops(&samsung_clk_syscore_ops);

        reg_cache->reg_base = reg_base;
        reg_cache->rd_num = nr_rdump;
        list_add_tail(&reg_cache->node, &clock_reg_cache_list);
}

#else
static void samsung_clk_sleep_init(void __iomem *reg_base,
                const unsigned long *rdump,
                unsigned long nr_rdump) {}
#endif

/*
 * Common function which registers plls, muxes, dividers and gates
 * for each CMU. It also add CMU register list to register cache.
 */
struct samsung_clk_provider * __init samsung_cmu_register_one(
                        struct device_node *np,
                        struct samsung_cmu_info *cmu)
{
        void __iomem *reg_base;
        struct samsung_clk_provider *ctx;

        reg_base = of_iomap(np, 0);
        if (!reg_base) {
                panic("%s: failed to map registers\n", __func__);
                return NULL;
        }

        ctx = samsung_clk_init(np, reg_base, cmu->nr_clk_ids);
        if (!ctx) {
                panic("%s: unable to alllocate ctx\n", __func__);
                return ctx;
        }

        if (cmu->pll_clks)
                samsung_clk_register_pll(ctx, cmu->pll_clks, cmu->nr_pll_clks,
                        reg_base);
        if (cmu->mux_clks)
                samsung_clk_register_mux(ctx, cmu->mux_clks,
                        cmu->nr_mux_clks);
        if (cmu->div_clks)
                samsung_clk_register_div(ctx, cmu->div_clks, cmu->nr_div_clks);
        if (cmu->gate_clks)
                samsung_clk_register_gate(ctx, cmu->gate_clks,
                        cmu->nr_gate_clks);
        if (cmu->fixed_clks)
                samsung_clk_register_fixed_rate(ctx, cmu->fixed_clks,
                        cmu->nr_fixed_clks);
        if (cmu->fixed_factor_clks)
                samsung_clk_register_fixed_factor(ctx, cmu->fixed_factor_clks,
                        cmu->nr_fixed_factor_clks);
        if (cmu->clk_regs)
                samsung_clk_sleep_init(reg_base, cmu->clk_regs,
                        cmu->nr_clk_regs);

        samsung_clk_of_add_provider(np, ctx);

        return ctx;
}