/*
 * TI clock support
 *
 * Copyright (C) 2013 Texas Instruments, Inc.
 *
 * Tero Kristo <t-kristo@ti.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 program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/ti.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/list.h>
#include <linux/regmap.h>
#include <linux/bootmem.h>
#include <linux/device.h>

#include "clock.h"

#undef pr_fmt
#define pr_fmt(fmt) "%s: " fmt, __func__

struct ti_clk_ll_ops *ti_clk_ll_ops;
static struct device_node *clocks_node_ptr[CLK_MAX_MEMMAPS];

static struct ti_clk_features ti_clk_features;

struct clk_iomap {
        struct regmap *regmap;
        void __iomem *mem;
};

static struct clk_iomap *clk_memmaps[CLK_MAX_MEMMAPS];

static void clk_memmap_writel(u32 val, const struct clk_omap_reg *reg)
{
        struct clk_iomap *io = clk_memmaps[reg->index];

        if (reg->ptr)
                writel_relaxed(val, reg->ptr);
        else if (io->regmap)
                regmap_write(io->regmap, reg->offset, val);
        else
                writel_relaxed(val, io->mem + reg->offset);
}

static u32 clk_memmap_readl(const struct clk_omap_reg *reg)
{
        u32 val;
        struct clk_iomap *io = clk_memmaps[reg->index];

        if (reg->ptr)
                val = readl_relaxed(reg->ptr);
        else if (io->regmap)
                regmap_read(io->regmap, reg->offset, &val);
        else
                val = readl_relaxed(io->mem + reg->offset);

        return val;
}

/**
 * ti_clk_setup_ll_ops - setup low level clock operations
 * @ops: low level clock ops descriptor
 *
 * Sets up low level clock operations for TI clock driver. This is used
 * to provide various callbacks for the clock driver towards platform
 * specific code. Returns 0 on success, -EBUSY if ll_ops have been
 * registered already.
 */
int ti_clk_setup_ll_ops(struct ti_clk_ll_ops *ops)
{
        if (ti_clk_ll_ops) {
                pr_err("Attempt to register ll_ops multiple times.\n");
                return -EBUSY;
        }

        ti_clk_ll_ops = ops;
        ops->clk_readl = clk_memmap_readl;
        ops->clk_writel = clk_memmap_writel;

        return 0;
}

/**
 * ti_dt_clocks_register - register DT alias clocks during boot
 * @oclks: list of clocks to register
 *
 * Register alias or non-standard DT clock entries during boot. By
 * default, DT clocks are found based on their node name. If any
 * additional con-id / dev-id -> clock mapping is required, use this
 * function to list these.
 */
void __init ti_dt_clocks_register(struct ti_dt_clk oclks[])
{
        struct ti_dt_clk *c;
        struct device_node *node;
        struct clk *clk;
        struct of_phandle_args clkspec;

        for (c = oclks; c->node_name != NULL; c++) {
                node = of_find_node_by_name(NULL, c->node_name);
                clkspec.np = node;
                clk = of_clk_get_from_provider(&clkspec);

                if (!IS_ERR(clk)) {
                        c->lk.clk = clk;
                        clkdev_add(&c->lk);
                } else {
                        pr_warn("failed to lookup clock node %s\n",
                                c->node_name);
                }
        }
}

struct clk_init_item {
        struct device_node *node;
        struct clk_hw *hw;
        ti_of_clk_init_cb_t func;
        struct list_head link;
};

static LIST_HEAD(retry_list);

/**
 * ti_clk_retry_init - retries a failed clock init at later phase
 * @node: device not for the clock
 * @hw: partially initialized clk_hw struct for the clock
 * @func: init function to be called for the clock
 *
 * Adds a failed clock init to the retry list. The retry list is parsed
 * once all the other clocks have been initialized.
 */
int __init ti_clk_retry_init(struct device_node *node, struct clk_hw *hw,
                              ti_of_clk_init_cb_t func)
{
        struct clk_init_item *retry;

        pr_debug("%s: adding to retry list...\n", node->name);
        retry = kzalloc(sizeof(*retry), GFP_KERNEL);
        if (!retry)
                return -ENOMEM;

        retry->node = node;
        retry->func = func;
        retry->hw = hw;
        list_add(&retry->link, &retry_list);

        return 0;
}

/**
 * ti_clk_get_reg_addr - get register address for a clock register
 * @node: device node for the clock
 * @index: register index from the clock node
 * @reg: pointer to target register struct
 *
 * Builds clock register address from device tree information, and returns
 * the data via the provided output pointer @reg. Returns 0 on success,
 * negative error value on failure.
 */
int ti_clk_get_reg_addr(struct device_node *node, int index,
                        struct clk_omap_reg *reg)
{
        u32 val;
        int i;

        for (i = 0; i < CLK_MAX_MEMMAPS; i++) {
                if (clocks_node_ptr[i] == node->parent)
                        break;
        }

        if (i == CLK_MAX_MEMMAPS) {
                pr_err("clk-provider not found for %s!\n", node->name);
                return -ENOENT;
        }

        reg->index = i;

        if (of_property_read_u32_index(node, "reg", index, &val)) {
                pr_err("%s must have reg[%d]!\n", node->name, index);
                return -EINVAL;
        }

        reg->offset = val;
        reg->ptr = NULL;

        return 0;
}

/**
 * omap2_clk_provider_init - init master clock provider
 * @parent: master node
 * @index: internal index for clk_reg_ops
 * @syscon: syscon regmap pointer for accessing clock registers
 * @mem: iomem pointer for the clock provider memory area, only used if
 *       syscon is not provided
 *
 * Initializes a master clock IP block. This basically sets up the
 * mapping from clocks node to the memory map index. All the clocks
 * are then initialized through the common of_clk_init call, and the
 * clocks will access their memory maps based on the node layout.
 * Returns 0 in success.
 */
int __init omap2_clk_provider_init(struct device_node *parent, int index,
                                   struct regmap *syscon, void __iomem *mem)
{
        struct device_node *clocks;
        struct clk_iomap *io;

        /* get clocks for this parent */
        clocks = of_get_child_by_name(parent, "clocks");
        if (!clocks) {
                pr_err("%s missing 'clocks' child node.\n", parent->name);
                return -EINVAL;
        }

        /* add clocks node info */
        clocks_node_ptr[index] = clocks;

        io = kzalloc(sizeof(*io), GFP_KERNEL);
        if (!io)
                return -ENOMEM;

        io->regmap = syscon;
        io->mem = mem;

        clk_memmaps[index] = io;

        return 0;
}

/**
 * omap2_clk_legacy_provider_init - initialize a legacy clock provider
 * @index: index for the clock provider
 * @mem: iomem pointer for the clock provider memory area
 *
 * Initializes a legacy clock provider memory mapping.
 */
void __init omap2_clk_legacy_provider_init(int index, void __iomem *mem)
{
        struct clk_iomap *io;

        io = memblock_virt_alloc(sizeof(*io), 0);

        io->mem = mem;

        clk_memmaps[index] = io;
}

/**
 * ti_dt_clk_init_retry_clks - init clocks from the retry list
 *
 * Initializes any clocks that have failed to initialize before,
 * reasons being missing parent node(s) during earlier init. This
 * typically happens only for DPLLs which need to have both of their
 * parent clocks ready during init.
 */
void ti_dt_clk_init_retry_clks(void)
{
        struct clk_init_item *retry;
        struct clk_init_item *tmp;
        int retries = 5;

        while (!list_empty(&retry_list) && retries) {
                list_for_each_entry_safe(retry, tmp, &retry_list, link) {
                        pr_debug("retry-init: %s\n", retry->node->name);
                        retry->func(retry->hw, retry->node);
                        list_del(&retry->link);
                        kfree(retry);
                }
                retries--;
        }
}

#if defined(CONFIG_ARCH_OMAP3) && defined(CONFIG_ATAGS)
void __init ti_clk_patch_legacy_clks(struct ti_clk **patch)
{
        while (*patch) {
                memcpy((*patch)->patch, *patch, sizeof(**patch));
                patch++;
        }
}

struct clk __init *ti_clk_register_clk(struct ti_clk *setup)
{
        struct clk *clk;
        struct ti_clk_fixed *fixed;
        struct ti_clk_fixed_factor *fixed_factor;
        struct clk_hw *clk_hw;
        int ret;

        if (setup->clk)
                return setup->clk;

        switch (setup->type) {
        case TI_CLK_FIXED:
                fixed = setup->data;

                clk = clk_register_fixed_rate(NULL, setup->name, NULL, 0,
                                              fixed->frequency);
                if (!IS_ERR(clk)) {
                        ret = ti_clk_add_alias(NULL, clk, setup->name);
                        if (ret) {
                                clk_unregister(clk);
                                clk = ERR_PTR(ret);
                        }
                }
                break;
        case TI_CLK_MUX:
                clk = ti_clk_register_mux(setup);
                break;
        case TI_CLK_DIVIDER:
                clk = ti_clk_register_divider(setup);
                break;
        case TI_CLK_COMPOSITE:
                clk = ti_clk_register_composite(setup);
                break;
        case TI_CLK_FIXED_FACTOR:
                fixed_factor = setup->data;

                clk = clk_register_fixed_factor(NULL, setup->name,
                                                fixed_factor->parent,
                                                0, fixed_factor->mult,
                                                fixed_factor->div);
                if (!IS_ERR(clk)) {
                        ret = ti_clk_add_alias(NULL, clk, setup->name);
                        if (ret) {
                                clk_unregister(clk);
                                clk = ERR_PTR(ret);
                        }
                }
                break;
        case TI_CLK_GATE:
                clk = ti_clk_register_gate(setup);
                break;
        case TI_CLK_DPLL:
                clk = ti_clk_register_dpll(setup);
                break;
        default:
                pr_err("bad type for %s!\n", setup->name);
                clk = ERR_PTR(-EINVAL);
        }

        if (!IS_ERR(clk)) {
                setup->clk = clk;
                if (setup->clkdm_name) {
                        clk_hw = __clk_get_hw(clk);
                        if (clk_hw_get_flags(clk_hw) & CLK_IS_BASIC) {
                                pr_warn("can't setup clkdm for basic clk %s\n",
                                        setup->name);
                        } else {
                                to_clk_hw_omap(clk_hw)->clkdm_name =
                                        setup->clkdm_name;
                                omap2_init_clk_clkdm(clk_hw);
                        }
                }
        }

        return clk;
}

int __init ti_clk_register_legacy_clks(struct ti_clk_alias *clks)
{
        struct clk *clk;
        bool retry;
        struct ti_clk_alias *retry_clk;
        struct ti_clk_alias *tmp;

        while (clks->clk) {
                clk = ti_clk_register_clk(clks->clk);
                if (IS_ERR(clk)) {
                        if (PTR_ERR(clk) == -EAGAIN) {
                                list_add(&clks->link, &retry_list);
                        } else {
                                pr_err("register for %s failed: %ld\n",
                                       clks->clk->name, PTR_ERR(clk));
                                return PTR_ERR(clk);
                        }
                }
                clks++;
        }

        retry = true;

        while (!list_empty(&retry_list) && retry) {
                retry = false;
                list_for_each_entry_safe(retry_clk, tmp, &retry_list, link) {
                        pr_debug("retry-init: %s\n", retry_clk->clk->name);
                        clk = ti_clk_register_clk(retry_clk->clk);
                        if (IS_ERR(clk)) {
                                if (PTR_ERR(clk) == -EAGAIN) {
                                        continue;
                                } else {
                                        pr_err("register for %s failed: %ld\n",
                                               retry_clk->clk->name,
                                               PTR_ERR(clk));
                                        return PTR_ERR(clk);
                                }
                        } else {
                                retry = true;
                                list_del(&retry_clk->link);
                        }
                }
        }

        return 0;
}
#endif

static const struct of_device_id simple_clk_match_table[] __initconst = {
        { .compatible = "fixed-clock" },
        { .compatible = "fixed-factor-clock" },
        { }
};

/**
 * ti_clk_add_aliases - setup clock aliases
 *
 * Sets up any missing clock aliases. No return value.
 */
void __init ti_clk_add_aliases(void)
{
        struct device_node *np;
        struct clk *clk;

        for_each_matching_node(np, simple_clk_match_table) {
                struct of_phandle_args clkspec;

                clkspec.np = np;
                clk = of_clk_get_from_provider(&clkspec);

                ti_clk_add_alias(NULL, clk, np->name);
        }
}

/**
 * ti_clk_setup_features - setup clock features flags
 * @features: features definition to use
 *
 * Initializes the clock driver features flags based on platform
 * provided data. No return value.
 */
void __init ti_clk_setup_features(struct ti_clk_features *features)
{
        memcpy(&ti_clk_features, features, sizeof(*features));
}

/**
 * ti_clk_get_features - get clock driver features flags
 *
 * Get TI clock driver features description. Returns a pointer
 * to the current feature setup.
 */
const struct ti_clk_features *ti_clk_get_features(void)
{
        return &ti_clk_features;
}

/**
 * omap2_clk_enable_init_clocks - prepare & enable a list of clocks
 * @clk_names: ptr to an array of strings of clock names to enable
 * @num_clocks: number of clock names in @clk_names
 *
 * Prepare and enable a list of clocks, named by @clk_names.  No
 * return value. XXX Deprecated; only needed until these clocks are
 * properly claimed and enabled by the drivers or core code that uses
 * them.  XXX What code disables & calls clk_put on these clocks?
 */
void omap2_clk_enable_init_clocks(const char **clk_names, u8 num_clocks)
{
        struct clk *init_clk;
        int i;

        for (i = 0; i < num_clocks; i++) {
                init_clk = clk_get(NULL, clk_names[i]);
                if (WARN(IS_ERR(init_clk), "could not find init clock %s\n",
                         clk_names[i]))
                        continue;
                clk_prepare_enable(init_clk);
        }
}

/**
 * ti_clk_add_alias - add a clock alias for a TI clock
 * @dev: device alias for this clock
 * @clk: clock handle to create alias for
 * @con: connection ID for this clock
 *
 * Creates a clock alias for a TI clock. Allocates the clock lookup entry
 * and assigns the data to it. Returns 0 if successful, negative error
 * value otherwise.
 */
int ti_clk_add_alias(struct device *dev, struct clk *clk, const char *con)
{
        struct clk_lookup *cl;

        if (!clk)
                return 0;

        if (IS_ERR(clk))
                return PTR_ERR(clk);

        cl = kzalloc(sizeof(*cl), GFP_KERNEL);
        if (!cl)
                return -ENOMEM;

        if (dev)
                cl->dev_id = dev_name(dev);
        cl->con_id = con;
        cl->clk = clk;

        clkdev_add(cl);

        return 0;
}

/**
 * ti_clk_register - register a TI clock to the common clock framework
 * @dev: device for this clock
 * @hw: hardware clock handle
 * @con: connection ID for this clock
 *
 * Registers a TI clock to the common clock framework, and adds a clock
 * alias for it. Returns a handle to the registered clock if successful,
 * ERR_PTR value in failure.
 */
struct clk *ti_clk_register(struct device *dev, struct clk_hw *hw,
                            const char *con)
{
        struct clk *clk;
        int ret;

        clk = clk_register(dev, hw);
        if (IS_ERR(clk))
                return clk;

        ret = ti_clk_add_alias(dev, clk, con);
        if (ret) {
                clk_unregister(clk);
                return ERR_PTR(ret);
        }

        return clk;
}