/*
 * Copyright (C) 2009-2016 Broadcom
 *
 * 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 in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#define pr_fmt(fmt) "clk-brcmstb: " fmt

#include <linux/io.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/syscore_ops.h>
#include <linux/brcmstb/brcmstb.h>

static bool shut_off_unused_clks = true;
static int bcm_full_clk = 2;
static void __iomem *cpu_clk_div_reg;

struct bcm_clk_gate {
	struct clk_hw hw;
	void __iomem *reg;
	u8 bit_idx;
	u8 flags;
	u32 delay[2];
	spinlock_t *lock;
	struct clk_ops ops;
};

struct bcm_clk_sw {
	struct clk_hw hw;
	struct clk_ops ops;
};

#define to_brcmstb_clk_gate(p) container_of(p, struct bcm_clk_gate, hw)
#define to_brcmstb_clk_sw(p) container_of(p, struct bcm_clk_sw, hw)

static DEFINE_SPINLOCK(lock);

static int cpu_clk_div_pos __initdata;
static int cpu_clk_div_width __initdata;

#ifdef CONFIG_PM_SLEEP
static u32 cpu_clk_div_reg_dump;

static int brcmstb_clk_suspend(void)
{
	if (cpu_clk_div_reg)
		cpu_clk_div_reg_dump = __raw_readl(cpu_clk_div_reg);
	return 0;
}

static void brcmstb_clk_resume(void)
{
	if (cpu_clk_div_reg)
		__raw_writel(cpu_clk_div_reg_dump, cpu_clk_div_reg);
}

static struct syscore_ops brcmstb_clk_syscore_ops = {
	.suspend = brcmstb_clk_suspend,
	.resume = brcmstb_clk_resume,
};
#endif /* CONFIG_PM_SLEEP */

static int __init parse_cpu_clk_div_dimensions(struct device_node *np)
{
	struct property *prop;
	const __be32 *p = NULL;
	int len;
	int elem_cnt;
	const char *propname = "div-shift-width";

	prop = of_find_property(np, propname, &len);
	if (!prop) {
		pr_err("%s property undefined\n", propname);
		return -EINVAL;
	}

	elem_cnt = len / sizeof(u32);

	if (elem_cnt != 2) {
		pr_err("%s should have only 2 elements\n", propname);
		return -EINVAL;
	}

	p = of_prop_next_u32(prop, p, &cpu_clk_div_pos);
	of_prop_next_u32(prop, p, &cpu_clk_div_width);

	return 0;
}

static struct clk_div_table *cpu_clk_div_table;

static int __init parse_cpu_clk_div_table(struct device_node *np)
{
	struct property *prop;
	const __be32 *p = NULL;
	struct clk_div_table *cur_tbl_ptr;
	int len;
	int elem_cnt;
	int i;
	const char *propname = "div-table";

	prop = of_find_property(np, propname, &len);
	if (!prop) {
		pr_err("%s property undefined\n", propname);
		return -EINVAL;
	}

	elem_cnt = len / sizeof(u32);

	if (elem_cnt < 2) {
		pr_err("%s should have at least 2 elements\n", propname);
		return -EINVAL;
	}

	if ((elem_cnt % 2) != 0) {
		pr_err("%s should have even number of elements\n", propname);
		return -EINVAL;
	}

	/* need room for last sentinel entry */
	len += 2 * sizeof(u32);

	cpu_clk_div_table = kmalloc(len, GFP_KERNEL);
	if (!cpu_clk_div_table)
		return -ENOMEM;

	cur_tbl_ptr = cpu_clk_div_table;

	for (i = 0; i < elem_cnt; i += 2) {
		p = of_prop_next_u32(prop, p, &cur_tbl_ptr->val);
		p = of_prop_next_u32(prop, p, &cur_tbl_ptr->div);

		cur_tbl_ptr++;
	}

	/* last entry should be zeroed out */
	cur_tbl_ptr->val = 0;
	cur_tbl_ptr->div = 0;

	return 0;
}

static void __init of_brcmstb_cpu_clk_div_setup(struct device_node *np)
{
	struct clk *clk;
	int rc;

	cpu_clk_div_reg = of_iomap(np, 0);
	if (!cpu_clk_div_reg) {
		pr_err("unable to iomap cpu clk divider register!\n");
		return;
	}

	rc = parse_cpu_clk_div_dimensions(np);
	if (rc)
		goto err;

	rc = parse_cpu_clk_div_table(np);
	if (rc)
		goto err;

	clk = clk_register_divider_table(NULL, "cpu-clk-div",
					 of_clk_get_parent_name(np, 0), 0,
					 cpu_clk_div_reg,
					 cpu_clk_div_pos, cpu_clk_div_width,
					 0, cpu_clk_div_table, &lock);
	if (IS_ERR(clk))
		goto err;

	rc = of_clk_add_provider(np, of_clk_src_simple_get, clk);
	if (rc) {
		pr_err("error adding clock provider (%d)\n", rc);
		goto err;
	}

#ifdef CONFIG_PM_SLEEP
	register_syscore_ops(&brcmstb_clk_syscore_ops);
#endif
	return;

err:
	kfree(cpu_clk_div_table);
	cpu_clk_div_table = NULL;

	if (cpu_clk_div_reg) {
		iounmap(cpu_clk_div_reg);
		cpu_clk_div_reg = NULL;
	}
}
CLK_OF_DECLARE(brcmstb_cpu_clk_div, "brcm,brcmstb-cpu-clk-div",
		of_brcmstb_cpu_clk_div_setup);

/*
 * It works on following logic:
 *
 * For enabling clock, enable = 1
 *	set2dis = 1	-> clear bit	-> set = 0
 *	set2dis = 0	-> set bit	-> set = 1
 *
 * For disabling clock, enable = 0
 *	set2dis = 1	-> set bit	-> set = 1
 *	set2dis = 0	-> clear bit	-> set = 0
 *
 * So, result is always: enable xor set2dis.
 */
static void brcmstb_clk_gate_endisable(struct clk_hw *hw, int enable)
{
	struct bcm_clk_gate *gate = to_brcmstb_clk_gate(hw);
	int set = gate->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
	unsigned long flags = 0;
	u32 reg;

	set ^= enable;

	if (gate->lock)
		spin_lock_irqsave(gate->lock, flags);

	reg = readl(gate->reg);

	if (set)
		reg |= BIT(gate->bit_idx);
	else
		reg &= ~BIT(gate->bit_idx);

	writel(reg, gate->reg);

	if (set == 0 && gate->delay[0])
		udelay(gate->delay[0]);
	else if (set == 1 && gate->delay[1])
		udelay(gate->delay[1]);

	if (gate->lock)
		spin_unlock_irqrestore(gate->lock, flags);
}

static int brcmstb_clk_gate_enable(struct clk_hw *hw)
{
	brcmstb_clk_gate_endisable(hw, 1);
	return 0;
}

static void brcmstb_clk_gate_disable(struct clk_hw *hw)
{
	brcmstb_clk_gate_endisable(hw, 0);
}

static int brcmstb_clk_gate_is_enabled(struct clk_hw *hw)
{
	u32 reg;
	struct bcm_clk_gate *gate = to_brcmstb_clk_gate(hw);

	reg = readl(gate->reg);

	/* if a set bit disables this clk, flip it before masking */
	if (gate->flags & CLK_GATE_SET_TO_DISABLE)
		reg ^= BIT(gate->bit_idx);

	reg &= BIT(gate->bit_idx);
	return reg ? 1 : 0;
}

static const struct clk_ops brcmstb_clk_gate_ops = {
	.enable = brcmstb_clk_gate_enable,
	.disable = brcmstb_clk_gate_disable,
	.is_enabled = brcmstb_clk_gate_is_enabled,
};

static const struct clk_ops brcmstb_clk_gate_inhib_dis_ops = {
	.enable = brcmstb_clk_gate_enable,
	.is_enabled = brcmstb_clk_gate_is_enabled,
};

static const struct clk_ops brcmstb_clk_gate_ro_ops = {
	.is_enabled = brcmstb_clk_gate_is_enabled,
};

/**
 * brcm_clk_gate_register - register a bcm gate clock with the clock framework.
 * @dev: device that is registering this clock
 * @name: name of this clock
 * @parent_name: name of this clock's parent
 * @flags: framework-specific flags for this clock
 * @reg: register address to control gating of this clock
 * @bit_idx: which bit in the register controls gating of this clock
 * @clk_gate_flags: gate-specific flags for this clock
 * @delay: usec delay in turning on, off.
 * @lock: shared register lock for this clock
 */
static struct clk __init *brcm_clk_gate_register(
	struct device *dev, const char *name, const char *parent_name,
	unsigned long flags, void __iomem *reg, u8 bit_idx,
	u8 clk_gate_flags, u32 delay[2], spinlock_t *lock,
	bool read_only, bool inhibit_disable)
{
	struct bcm_clk_gate *gate;
	struct clk *clk;
	struct clk_init_data init;

	/* allocate the gate */
	gate = kzalloc(sizeof(struct bcm_clk_gate), GFP_KERNEL);
	if (!gate) {
		pr_err("%s: could not allocate bcm gated clk\n", __func__);
		return ERR_PTR(-ENOMEM);
	}

	init.name = name;
	init.ops = inhibit_disable ? &brcmstb_clk_gate_inhib_dis_ops
		: read_only ? &brcmstb_clk_gate_ro_ops : &brcmstb_clk_gate_ops;
	init.parent_names = (parent_name ? &parent_name : NULL);
	init.num_parents = (parent_name ? 1 : 0);
	init.flags = flags | (parent_name ? 0 : CLK_IS_ROOT);
	if (!shut_off_unused_clks)
		init.flags |= CLK_IGNORE_UNUSED; /* FIXME */

	/* struct bcm_gate assignments */
	gate->reg = reg;
	gate->bit_idx = bit_idx;
	gate->flags = clk_gate_flags;
	gate->lock = lock;
	gate->delay[0] = delay[0];
	gate->delay[1] = delay[1];
	gate->hw.init = &init;

	clk = clk_register(dev, &gate->hw);

	if (IS_ERR(clk))
		kfree(gate);

	return clk;
}

static const struct clk_ops brcmstb_clk_sw_ops = {};

/**
 * brcmstb_clk_sw_register - register a bcm gate clock with the clock framework.
 * @dev: device that is registering this clock
 * @name: name of this clock
 * @parents: name of this clock's parents; not known by clock framework
 * @num_parents: number of parents
 * @flags: framework-specific flags for this clock
 * @lock: shared register lock for this clock
 */
static struct clk __init *brcmstb_clk_sw_register(
	struct device *dev, const char *name, const char **parent_names,
	int num_parents, unsigned long flags, spinlock_t *lock)
{
	struct bcm_clk_sw *sw_clk;
	struct clk *clk;
	struct clk_init_data init;

	/* allocate the gate */
	sw_clk = kzalloc(sizeof(struct bcm_clk_sw), GFP_KERNEL);
	if (!sw_clk) {
		pr_err("%s: could not allocate bcm sw clk\n", __func__);
		return ERR_PTR(-ENOMEM);
	}

	init.name = name;
	init.ops = &brcmstb_clk_sw_ops;
	init.parent_names = parent_names;
	init.num_parents = num_parents;
	init.flags = flags | CLK_IS_BASIC | CLK_IS_SW;
	if (!shut_off_unused_clks)
		init.flags |= CLK_IGNORE_UNUSED; /* FIXME */

	sw_clk->hw.init = &init;
	clk = clk_register(dev, &sw_clk->hw);
	if (IS_ERR(clk))
		kfree(sw_clk);
	return clk;
}

/**
 * of_brcmstb_gate_clk_setup() - Setup function for brcmstb gate clock
 */
static void __init of_brcmstb_clk_gate_setup(struct device_node *node)
{
	struct clk *clk;
	const char *clk_name = node->name;
	void __iomem *reg;
	const char *parent_name;
	u8 clk_gate_flags = 0;
	u32 bit_idx = 0;
	u32 delay[2] = {0, 0};
	int ret;
	bool read_only = false;
	bool inhibit_disable = false;

	of_property_read_string(node, "clock-output-names", &clk_name);
	parent_name = of_clk_get_parent_name(node, 0);
	if (of_property_read_u32(node, "bit-shift", &bit_idx)) {
		pr_err("%s: missing bit-shift property for %s\n",
				__func__, node->name);
		return;
	}
	reg = of_iomap(node, 0);
	if (!reg) {
		pr_err("unable to iomap cpu clk divider register!\n");
		return;
	}

	of_property_read_u32_array(node, "brcm,delay", delay, 2);

	if (of_property_read_bool(node, "set-bit-to-disable"))
		clk_gate_flags |= CLK_GATE_SET_TO_DISABLE;

	if (of_property_read_bool(node, "brcm,read-only"))
		read_only = true;

	if (of_property_read_bool(node, "brcm,inhibit-disable"))
		inhibit_disable = true;

	clk = brcm_clk_gate_register(NULL, clk_name, parent_name, 0, reg,
				     (u8) bit_idx, clk_gate_flags, delay,
				     &lock, read_only, inhibit_disable);
	if (!IS_ERR(clk)) {
		of_clk_add_provider(node, of_clk_src_simple_get, clk);
		ret = clk_register_clkdev(clk, clk_name, NULL);
		if (ret)
			pr_err("%s: clk device registration failed for '%s'\n",
			       __func__, clk_name);
	}
}
CLK_OF_DECLARE(brcmstb_clk_gate, "brcm,brcmstb-gate-clk",
		of_brcmstb_clk_gate_setup);

static void __init of_brcmstb_clk_sw_setup(struct device_node *node)
{
	struct clk *clk;
	const char *clk_name = node->name;
	int num_parents;
	const char **parent_names;
	int ret, i;

	of_property_read_string(node, "clock-output-names", &clk_name);
	num_parents = of_property_count_strings(node, "clock-names");
	if (num_parents < 1) {
		pr_err("%s: brcm-sw-clock %s must have parent(s)\n",
				__func__, node->name);
		return;
	}
	parent_names = kzalloc((sizeof(char *) * num_parents),
			GFP_KERNEL);
	if (!parent_names) {
		pr_err("%s: failed to alloc parent_names\n", __func__);
		return;
	}

	for (i = 0; i < num_parents; i++)
		parent_names[i] = of_clk_get_parent_name(node, i);

	clk = brcmstb_clk_sw_register(NULL, clk_name, parent_names, num_parents,
				   0, NULL);
	kfree(parent_names);

	if (!IS_ERR(clk)) {
		of_clk_add_provider(node, of_clk_src_simple_get, clk);
		ret = clk_register_clkdev(clk, clk_name, NULL);
		if (ret)
			pr_err("%s: clk device registration failed for '%s'\n",
			       __func__, clk_name);
	}
}
CLK_OF_DECLARE(brcmstb_clk_sw, "brcm,brcmstb-sw-clk",
		of_brcmstb_clk_sw_setup);

static int __init _bcm_full_clk(char *str)
{
	get_option(&str, &bcm_full_clk);
	shut_off_unused_clks = bcm_full_clk > 1;
	return 0;
}

early_param("bcm_full_clk", _bcm_full_clk);