/*
 * Copyright (c) 2016 Rockchip Electronics Co. Ltd.
 * Author: Lin Huang <hl@rock-chips.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 */

#include <linux/arm-smccc.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <soc/rockchip/rockchip_sip.h>
#include "clk.h"

struct rockchip_ddrclk {
	struct clk_hw	hw;
	void __iomem	*reg_base;
	int		mux_offset;
	int		mux_shift;
	int		mux_width;
	int		div_shift;
	int		div_width;
	int		ddr_flag;
	spinlock_t	*lock;
};

#define to_rockchip_ddrclk_hw(hw) container_of(hw, struct rockchip_ddrclk, hw)

static int rockchip_ddrclk_sip_set_rate(struct clk_hw *hw, unsigned long drate,
					unsigned long prate)
{
	struct rockchip_ddrclk *ddrclk = to_rockchip_ddrclk_hw(hw);
	unsigned long flags;
	struct arm_smccc_res res;

	spin_lock_irqsave(ddrclk->lock, flags);
	arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, drate, 0,
		      ROCKCHIP_SIP_CONFIG_DRAM_SET_RATE,
		      0, 0, 0, 0, &res);
	spin_unlock_irqrestore(ddrclk->lock, flags);

	return res.a0;
}

static unsigned long
rockchip_ddrclk_sip_recalc_rate(struct clk_hw *hw,
				unsigned long parent_rate)
{
	struct arm_smccc_res res;

	arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, 0, 0,
		      ROCKCHIP_SIP_CONFIG_DRAM_GET_RATE,
		      0, 0, 0, 0, &res);

	return res.a0;
}

static long rockchip_ddrclk_sip_round_rate(struct clk_hw *hw,
					   unsigned long rate,
					   unsigned long *prate)
{
	struct arm_smccc_res res;

	arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, rate, 0,
		      ROCKCHIP_SIP_CONFIG_DRAM_ROUND_RATE,
		      0, 0, 0, 0, &res);

	return res.a0;
}

static u8 rockchip_ddrclk_get_parent(struct clk_hw *hw)
{
	struct rockchip_ddrclk *ddrclk = to_rockchip_ddrclk_hw(hw);
	int num_parents = clk_hw_get_num_parents(hw);
	u32 val;

	val = clk_readl(ddrclk->reg_base +
			ddrclk->mux_offset) >> ddrclk->mux_shift;
	val &= GENMASK(ddrclk->mux_width - 1, 0);

	if (val >= num_parents)
		return -EINVAL;

	return val;
}

static const struct clk_ops rockchip_ddrclk_sip_ops = {
	.recalc_rate = rockchip_ddrclk_sip_recalc_rate,
	.set_rate = rockchip_ddrclk_sip_set_rate,
	.round_rate = rockchip_ddrclk_sip_round_rate,
	.get_parent = rockchip_ddrclk_get_parent,
};

struct clk *rockchip_clk_register_ddrclk(const char *name, int flags,
					 const char *const *parent_names,
					 u8 num_parents, int mux_offset,
					 int mux_shift, int mux_width,
					 int div_shift, int div_width,
					 int ddr_flag, void __iomem *reg_base,
					 spinlock_t *lock)
{
	struct rockchip_ddrclk *ddrclk;
	struct clk_init_data init;
	struct clk *clk;

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

	init.name = name;
	init.parent_names = parent_names;
	init.num_parents = num_parents;

	init.flags = flags;
	init.flags |= CLK_SET_RATE_NO_REPARENT;

	switch (ddr_flag) {
	case ROCKCHIP_DDRCLK_SIP:
		init.ops = &rockchip_ddrclk_sip_ops;
		break;
	default:
		pr_err("%s: unsupported ddrclk type %d\n", __func__, ddr_flag);
		kfree(ddrclk);
		return ERR_PTR(-EINVAL);
	}

	ddrclk->reg_base = reg_base;
	ddrclk->lock = lock;
	ddrclk->hw.init = &init;
	ddrclk->mux_offset = mux_offset;
	ddrclk->mux_shift = mux_shift;
	ddrclk->mux_width = mux_width;
	ddrclk->div_shift = div_shift;
	ddrclk->div_width = div_width;
	ddrclk->ddr_flag = ddr_flag;

	clk = clk_register(NULL, &ddrclk->hw);
	if (IS_ERR(clk))
		kfree(ddrclk);

	return clk;
}