/*
   * Copyright (c) 2014 MundoReader S.L.
   * Author: Heiko Stuebner <heiko@sntech.de>
   *
   * 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 <asm/div64.h>
  #include <linux/slab.h>
  #include <linux/io.h>
  #include <linux/delay.h>
  #include <linux/clk-provider.h>
  #include <linux/regmap.h>
  #include "clk.h"
  
  #define PLL_MODE_MASK		0x3
  #define PLL_MODE_SLOW		0x0
  #define PLL_MODE_NORM		0x1
  #define PLL_MODE_DEEP		0x2
  
  struct rockchip_clk_pll {
  	struct clk_hw		hw;
  
  	struct clk_mux		pll_mux;
  	const struct clk_ops	*pll_mux_ops;
  
  	struct notifier_block	clk_nb;
  
  	void __iomem		*reg_base;
  	int			lock_offset;
  	unsigned int		lock_shift;
  	enum rockchip_pll_type	type;
  	u8			flags;
  	const struct rockchip_pll_rate_table *rate_table;
  	unsigned int		rate_count;
  	spinlock_t		*lock;
  };
  
  #define to_rockchip_clk_pll(_hw) container_of(_hw, struct rockchip_clk_pll, hw)
  #define to_rockchip_clk_pll_nb(nb) \
  			container_of(nb, struct rockchip_clk_pll, clk_nb)
  
  static const struct rockchip_pll_rate_table *rockchip_get_pll_settings(
  			    struct rockchip_clk_pll *pll, unsigned long rate)
  {
  	const struct rockchip_pll_rate_table  *rate_table = pll->rate_table;
  	int i;
  
  	for (i = 0; i < pll->rate_count; i++) {
  		if (rate == rate_table[i].rate)
  			return &rate_table[i];
  	}
  
  	return NULL;
  }
  
  static long rockchip_pll_round_rate(struct clk_hw *hw,
  			    unsigned long drate, unsigned long *prate)
  {
  	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
  	const struct rockchip_pll_rate_table *rate_table = pll->rate_table;
  	int i;
  
  	/* Assumming rate_table is in descending order */
  	for (i = 0; i < pll->rate_count; i++) {
  		if (drate >= rate_table[i].rate)
  			return rate_table[i].rate;
  	}
  
  	/* return minimum supported value */
  	return rate_table[i - 1].rate;
  }
  
  /*
   * Wait for the pll to reach the locked state.
   * The calling set_rate function is responsible for making sure the
   * grf regmap is available.
   */
  static int rockchip_pll_wait_lock(struct rockchip_clk_pll *pll)
  {
  	struct regmap *grf = rockchip_clk_get_grf();
  	unsigned int val;
  	int delay = 24000000, ret;
  
  	while (delay > 0) {
  		ret = regmap_read(grf, pll->lock_offset, &val);
  		if (ret) {
  			pr_err("%s: failed to read pll lock status: %d
  ",
  			       __func__, ret);
  			return ret;
  		}
  
  		if (val & BIT(pll->lock_shift))
  			return 0;
  		delay--;
  	}
  
  	pr_err("%s: timeout waiting for pll to lock
  ", __func__);
  	return -ETIMEDOUT;
  }
  
  /**
   * PLL used in RK3066, RK3188 and RK3288
   */
  
  #define RK3066_PLL_RESET_DELAY(nr)	((nr * 500) / 24 + 1)
  
  #define RK3066_PLLCON(i)		(i * 0x4)
  #define RK3066_PLLCON0_OD_MASK		0xf
  #define RK3066_PLLCON0_OD_SHIFT		0
  #define RK3066_PLLCON0_NR_MASK		0x3f
  #define RK3066_PLLCON0_NR_SHIFT		8
  #define RK3066_PLLCON1_NF_MASK		0x1fff
  #define RK3066_PLLCON1_NF_SHIFT		0
  #define RK3066_PLLCON2_NB_MASK		0xfff
  #define RK3066_PLLCON2_NB_SHIFT		0
  #define RK3066_PLLCON3_RESET		(1 << 5)
  #define RK3066_PLLCON3_PWRDOWN		(1 << 1)
  #define RK3066_PLLCON3_BYPASS		(1 << 0)
  
  static void rockchip_rk3066_pll_get_params(struct rockchip_clk_pll *pll,
  					struct rockchip_pll_rate_table *rate)
  {
  	u32 pllcon;
  
  	pllcon = readl_relaxed(pll->reg_base + RK3066_PLLCON(0));
  	rate->nr = ((pllcon >> RK3066_PLLCON0_NR_SHIFT)
  				& RK3066_PLLCON0_NR_MASK) + 1;
  	rate->no = ((pllcon >> RK3066_PLLCON0_OD_SHIFT)
  				& RK3066_PLLCON0_OD_MASK) + 1;
  
  	pllcon = readl_relaxed(pll->reg_base + RK3066_PLLCON(1));
  	rate->nf = ((pllcon >> RK3066_PLLCON1_NF_SHIFT)
  				& RK3066_PLLCON1_NF_MASK) + 1;
  
  	pllcon = readl_relaxed(pll->reg_base + RK3066_PLLCON(2));
  	rate->nb = ((pllcon >> RK3066_PLLCON2_NB_SHIFT)
  				& RK3066_PLLCON2_NB_MASK) + 1;
  }
  
  static unsigned long rockchip_rk3066_pll_recalc_rate(struct clk_hw *hw,
  						     unsigned long prate)
  {
  	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
  	struct rockchip_pll_rate_table cur;
  	u64 rate64 = prate;
  	u32 pllcon;
  
  	pllcon = readl_relaxed(pll->reg_base + RK3066_PLLCON(3));
  	if (pllcon & RK3066_PLLCON3_BYPASS) {
  		pr_debug("%s: pll %s is bypassed
  ", __func__,
  			clk_hw_get_name(hw));
  		return prate;
  	}
  
  	rockchip_rk3066_pll_get_params(pll, &cur);
  
  	rate64 *= cur.nf;
  	do_div(rate64, cur.nr);
  	do_div(rate64, cur.no);
  
  	return (unsigned long)rate64;
  }
  
  static int rockchip_rk3066_pll_set_params(struct rockchip_clk_pll *pll,
  				const struct rockchip_pll_rate_table *rate)
  {
  	const struct clk_ops *pll_mux_ops = pll->pll_mux_ops;
  	struct clk_mux *pll_mux = &pll->pll_mux;
  	struct rockchip_pll_rate_table cur;
  	int rate_change_remuxed = 0;
  	int cur_parent;
  	int ret;
  
  	pr_debug("%s: rate settings for %lu (nr, no, nf): (%d, %d, %d)
  ",
  		 __func__, rate->rate, rate->nr, rate->no, rate->nf);
  
  	rockchip_rk3066_pll_get_params(pll, &cur);
  	cur.rate = 0;
  
  	cur_parent = pll_mux_ops->get_parent(&pll_mux->hw);
  	if (cur_parent == PLL_MODE_NORM) {
  		pll_mux_ops->set_parent(&pll_mux->hw, PLL_MODE_SLOW);
  		rate_change_remuxed = 1;
  	}
  
  	/* enter reset mode */
  	writel(HIWORD_UPDATE(RK3066_PLLCON3_RESET, RK3066_PLLCON3_RESET, 0),
  	       pll->reg_base + RK3066_PLLCON(3));
  
  	/* update pll values */
  	writel(HIWORD_UPDATE(rate->nr - 1, RK3066_PLLCON0_NR_MASK,
  					   RK3066_PLLCON0_NR_SHIFT) |
  	       HIWORD_UPDATE(rate->no - 1, RK3066_PLLCON0_OD_MASK,
  					   RK3066_PLLCON0_OD_SHIFT),
  	       pll->reg_base + RK3066_PLLCON(0));
  
  	writel_relaxed(HIWORD_UPDATE(rate->nf - 1, RK3066_PLLCON1_NF_MASK,
  						   RK3066_PLLCON1_NF_SHIFT),
  		       pll->reg_base + RK3066_PLLCON(1));
  	writel_relaxed(HIWORD_UPDATE(rate->nb - 1, RK3066_PLLCON2_NB_MASK,
  						   RK3066_PLLCON2_NB_SHIFT),
  		       pll->reg_base + RK3066_PLLCON(2));
  
  	/* leave reset and wait the reset_delay */
  	writel(HIWORD_UPDATE(0, RK3066_PLLCON3_RESET, 0),
  	       pll->reg_base + RK3066_PLLCON(3));
  	udelay(RK3066_PLL_RESET_DELAY(rate->nr));
  
  	/* wait for the pll to lock */
  	ret = rockchip_pll_wait_lock(pll);
  	if (ret) {
  		pr_warn("%s: pll update unsucessful, trying to restore old params
  ",
  			__func__);
  		rockchip_rk3066_pll_set_params(pll, &cur);
  	}
  
  	if (rate_change_remuxed)
  		pll_mux_ops->set_parent(&pll_mux->hw, PLL_MODE_NORM);
  
  	return ret;
  }
  
  static int rockchip_rk3066_pll_set_rate(struct clk_hw *hw, unsigned long drate,
  					unsigned long prate)
  {
  	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
  	const struct rockchip_pll_rate_table *rate;
  	unsigned long old_rate = rockchip_rk3066_pll_recalc_rate(hw, prate);
  	struct regmap *grf = rockchip_clk_get_grf();
  
  	if (IS_ERR(grf)) {
  		pr_debug("%s: grf regmap not available, aborting rate change
  ",
  			 __func__);
  		return PTR_ERR(grf);
  	}
  
  	pr_debug("%s: changing %s from %lu to %lu with a parent rate of %lu
  ",
  		 __func__, clk_hw_get_name(hw), old_rate, drate, prate);
  
  	/* Get required rate settings from table */
  	rate = rockchip_get_pll_settings(pll, drate);
  	if (!rate) {
  		pr_err("%s: Invalid rate : %lu for pll clk %s
  ", __func__,
  			drate, clk_hw_get_name(hw));
  		return -EINVAL;
  	}
  
  	return rockchip_rk3066_pll_set_params(pll, rate);
  }
  
  static int rockchip_rk3066_pll_enable(struct clk_hw *hw)
  {
  	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
  
  	writel(HIWORD_UPDATE(0, RK3066_PLLCON3_PWRDOWN, 0),
  	       pll->reg_base + RK3066_PLLCON(3));
  
  	return 0;
  }
  
  static void rockchip_rk3066_pll_disable(struct clk_hw *hw)
  {
  	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
  
  	writel(HIWORD_UPDATE(RK3066_PLLCON3_PWRDOWN,
  			     RK3066_PLLCON3_PWRDOWN, 0),
  	       pll->reg_base + RK3066_PLLCON(3));
  }
  
  static int rockchip_rk3066_pll_is_enabled(struct clk_hw *hw)
  {
  	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
  	u32 pllcon = readl(pll->reg_base + RK3066_PLLCON(3));
  
  	return !(pllcon & RK3066_PLLCON3_PWRDOWN);
  }
  
  static void rockchip_rk3066_pll_init(struct clk_hw *hw)
  {
  	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
  	const struct rockchip_pll_rate_table *rate;
  	struct rockchip_pll_rate_table cur;
  	unsigned long drate;
  
  	if (!(pll->flags & ROCKCHIP_PLL_SYNC_RATE))
  		return;
  
  	drate = clk_hw_get_rate(hw);
  	rate = rockchip_get_pll_settings(pll, drate);
  
  	/* when no rate setting for the current rate, rely on clk_set_rate */
  	if (!rate)
  		return;
  
  	rockchip_rk3066_pll_get_params(pll, &cur);
  
  	pr_debug("%s: pll %s@%lu: nr (%d:%d); no (%d:%d); nf(%d:%d), nb(%d:%d)
  ",
  		 __func__, clk_hw_get_name(hw), drate, rate->nr, cur.nr,
  		 rate->no, cur.no, rate->nf, cur.nf, rate->nb, cur.nb);
  	if (rate->nr != cur.nr || rate->no != cur.no || rate->nf != cur.nf
  						     || rate->nb != cur.nb) {
  		struct regmap *grf = rockchip_clk_get_grf();
  
  		if (IS_ERR(grf))
  			return;
  
  		pr_debug("%s: pll %s: rate params do not match rate table, adjusting
  ",
  			 __func__, clk_hw_get_name(hw));
  		rockchip_rk3066_pll_set_params(pll, rate);
  	}
  }
  
  static const struct clk_ops rockchip_rk3066_pll_clk_norate_ops = {
  	.recalc_rate = rockchip_rk3066_pll_recalc_rate,
  	.enable = rockchip_rk3066_pll_enable,
  	.disable = rockchip_rk3066_pll_disable,
  	.is_enabled = rockchip_rk3066_pll_is_enabled,
  };
  
  static const struct clk_ops rockchip_rk3066_pll_clk_ops = {
  	.recalc_rate = rockchip_rk3066_pll_recalc_rate,
  	.round_rate = rockchip_pll_round_rate,
  	.set_rate = rockchip_rk3066_pll_set_rate,
  	.enable = rockchip_rk3066_pll_enable,
  	.disable = rockchip_rk3066_pll_disable,
  	.is_enabled = rockchip_rk3066_pll_is_enabled,
  	.init = rockchip_rk3066_pll_init,
  };
  
  /*
   * Common registering of pll clocks
   */
  
  struct clk *rockchip_clk_register_pll(enum rockchip_pll_type pll_type,
  		const char *name, const char *const *parent_names,
  		u8 num_parents, void __iomem *base, int con_offset,
  		int grf_lock_offset, int lock_shift, int mode_offset,
  		int mode_shift, struct rockchip_pll_rate_table *rate_table,
  		u8 clk_pll_flags, spinlock_t *lock)
  {
  	const char *pll_parents[3];
  	struct clk_init_data init;
  	struct rockchip_clk_pll *pll;
  	struct clk_mux *pll_mux;
  	struct clk *pll_clk, *mux_clk;
  	char pll_name[20];
  
  	if (num_parents != 2) {
  		pr_err("%s: needs two parent clocks
  ", __func__);
  		return ERR_PTR(-EINVAL);
  	}
  
  	/* name the actual pll */
  	snprintf(pll_name, sizeof(pll_name), "pll_%s", name);
  
  	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
  	if (!pll)
  		return ERR_PTR(-ENOMEM);
  
  	/* create the mux on top of the real pll */
  	pll->pll_mux_ops = &clk_mux_ops;
  	pll_mux = &pll->pll_mux;
  	pll_mux->reg = base + mode_offset;
  	pll_mux->shift = mode_shift;
  	pll_mux->mask = PLL_MODE_MASK;
  	pll_mux->flags = 0;
  	pll_mux->lock = lock;
  	pll_mux->hw.init = &init;
  
  	if (pll_type == pll_rk3066)
  		pll_mux->flags |= CLK_MUX_HIWORD_MASK;
  
  	/* the actual muxing is xin24m, pll-output, xin32k */
  	pll_parents[0] = parent_names[0];
  	pll_parents[1] = pll_name;
  	pll_parents[2] = parent_names[1];
  
  	init.name = name;
  	init.flags = CLK_SET_RATE_PARENT;
  	init.ops = pll->pll_mux_ops;
  	init.parent_names = pll_parents;
  	init.num_parents = ARRAY_SIZE(pll_parents);
  
  	mux_clk = clk_register(NULL, &pll_mux->hw);
  	if (IS_ERR(mux_clk))
  		goto err_mux;
  
  	/* now create the actual pll */
  	init.name = pll_name;
  
  	/* keep all plls untouched for now */
  	init.flags = CLK_IGNORE_UNUSED;
  
  	init.parent_names = &parent_names[0];
  	init.num_parents = 1;
  
  	if (rate_table) {
  		int len;
  
  		/* find count of rates in rate_table */
  		for (len = 0; rate_table[len].rate != 0; )
  			len++;
  
  		pll->rate_count = len;
  		pll->rate_table = kmemdup(rate_table,
  					pll->rate_count *
  					sizeof(struct rockchip_pll_rate_table),
  					GFP_KERNEL);
  		WARN(!pll->rate_table,
  			"%s: could not allocate rate table for %s
  ",
  			__func__, name);
  	}
  
  	switch (pll_type) {
  	case pll_rk3066:
  		if (!pll->rate_table)
  			init.ops = &rockchip_rk3066_pll_clk_norate_ops;
  		else
  			init.ops = &rockchip_rk3066_pll_clk_ops;
  		break;
  	default:
  		pr_warn("%s: Unknown pll type for pll clk %s
  ",
  			__func__, name);
  	}
  
  	pll->hw.init = &init;
  	pll->type = pll_type;
  	pll->reg_base = base + con_offset;
  	pll->lock_offset = grf_lock_offset;
  	pll->lock_shift = lock_shift;
  	pll->flags = clk_pll_flags;
  	pll->lock = lock;
  
  	pll_clk = clk_register(NULL, &pll->hw);
  	if (IS_ERR(pll_clk)) {
  		pr_err("%s: failed to register pll clock %s : %ld
  ",
  			__func__, name, PTR_ERR(pll_clk));
  		goto err_pll;
  	}
  
  	return mux_clk;
  
  err_pll:
  	clk_unregister(mux_clk);
  	mux_clk = pll_clk;
  err_mux:
  	kfree(pll);
  	return mux_clk;
  }