clock.c 15.8 KB
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/*
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 * Clock and PLL control for DaVinci devices
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 *
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 * Copyright (C) 2006-2007 Texas Instruments.
 * Copyright (C) 2008-2009 Deep Root Systems, LLC
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 *
 * 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.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
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#include <linux/clk.h>
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#include <linux/err.h>
#include <linux/mutex.h>
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#include <linux/io.h>
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#include <linux/delay.h>
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#include <mach/hardware.h>
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#include <mach/clock.h>
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#include "psc.h"
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#include <mach/cputype.h>
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#include "clock.h"

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
static DEFINE_SPINLOCK(clockfw_lock);

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void davinci_clk_enable(struct clk *clk)
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{
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	if (clk->parent)
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		davinci_clk_enable(clk->parent);
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	if (clk->usecount++ == 0) {
		if (clk->flags & CLK_PSC)
			davinci_psc_config(clk->domain, clk->gpsc, clk->lpsc,
					   true, clk->flags);
		else if (clk->clk_enable)
			clk->clk_enable(clk);
	}
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}

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void davinci_clk_disable(struct clk *clk)
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{
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	if (WARN_ON(clk->usecount == 0))
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		return;
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	if (--clk->usecount == 0) {
		if (!(clk->flags & CLK_PLL) && (clk->flags & CLK_PSC))
			davinci_psc_config(clk->domain, clk->gpsc, clk->lpsc,
					   false, clk->flags);
		else if (clk->clk_disable)
			clk->clk_disable(clk);
	}
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	if (clk->parent)
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		davinci_clk_disable(clk->parent);
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}

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int davinci_clk_reset(struct clk *clk, bool reset)
{
	unsigned long flags;

	if (clk == NULL || IS_ERR(clk))
		return -EINVAL;

	spin_lock_irqsave(&clockfw_lock, flags);
	if (clk->flags & CLK_PSC)
		davinci_psc_reset(clk->gpsc, clk->lpsc, reset);
	spin_unlock_irqrestore(&clockfw_lock, flags);

	return 0;
}
EXPORT_SYMBOL(davinci_clk_reset);

int davinci_clk_reset_assert(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk) || !clk->reset)
		return -EINVAL;

	return clk->reset(clk, true);
}
EXPORT_SYMBOL(davinci_clk_reset_assert);

int davinci_clk_reset_deassert(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk) || !clk->reset)
		return -EINVAL;

	return clk->reset(clk, false);
}
EXPORT_SYMBOL(davinci_clk_reset_deassert);

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int clk_enable(struct clk *clk)
{
	unsigned long flags;

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	if (!clk)
		return 0;
	else if (IS_ERR(clk))
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		return -EINVAL;

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	spin_lock_irqsave(&clockfw_lock, flags);
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	davinci_clk_enable(clk);
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	spin_unlock_irqrestore(&clockfw_lock, flags);
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	return 0;
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}
EXPORT_SYMBOL(clk_enable);

void clk_disable(struct clk *clk)
{
	unsigned long flags;

	if (clk == NULL || IS_ERR(clk))
		return;

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	spin_lock_irqsave(&clockfw_lock, flags);
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	davinci_clk_disable(clk);
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	spin_unlock_irqrestore(&clockfw_lock, flags);
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}
EXPORT_SYMBOL(clk_disable);

unsigned long clk_get_rate(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
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		return 0;
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	return clk->rate;
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}
EXPORT_SYMBOL(clk_get_rate);

long clk_round_rate(struct clk *clk, unsigned long rate)
{
	if (clk == NULL || IS_ERR(clk))
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		return 0;
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	if (clk->round_rate)
		return clk->round_rate(clk, rate);

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	return clk->rate;
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}
EXPORT_SYMBOL(clk_round_rate);

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/* Propagate rate to children */
static void propagate_rate(struct clk *root)
{
	struct clk *clk;

	list_for_each_entry(clk, &root->children, childnode) {
		if (clk->recalc)
			clk->rate = clk->recalc(clk);
		propagate_rate(clk);
	}
}

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int clk_set_rate(struct clk *clk, unsigned long rate)
{
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	unsigned long flags;
	int ret = -EINVAL;

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	if (!clk)
		return 0;
	else if (IS_ERR(clk))
		return -EINVAL;
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	if (clk->set_rate)
		ret = clk->set_rate(clk, rate);
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	spin_lock_irqsave(&clockfw_lock, flags);
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	if (ret == 0) {
		if (clk->recalc)
			clk->rate = clk->recalc(clk);
		propagate_rate(clk);
	}
	spin_unlock_irqrestore(&clockfw_lock, flags);
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	return ret;
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}
EXPORT_SYMBOL(clk_set_rate);

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int clk_set_parent(struct clk *clk, struct clk *parent)
{
	unsigned long flags;

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	if (!clk)
		return 0;
	else if (IS_ERR(clk))
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		return -EINVAL;

	/* Cannot change parent on enabled clock */
	if (WARN_ON(clk->usecount))
		return -EINVAL;

	mutex_lock(&clocks_mutex);
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	if (clk->set_parent) {
		int ret = clk->set_parent(clk, parent);

		if (ret) {
			mutex_unlock(&clocks_mutex);
			return ret;
		}
	}
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	clk->parent = parent;
	list_del_init(&clk->childnode);
	list_add(&clk->childnode, &clk->parent->children);
	mutex_unlock(&clocks_mutex);

	spin_lock_irqsave(&clockfw_lock, flags);
	if (clk->recalc)
		clk->rate = clk->recalc(clk);
	propagate_rate(clk);
	spin_unlock_irqrestore(&clockfw_lock, flags);

	return 0;
}
EXPORT_SYMBOL(clk_set_parent);

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struct clk *clk_get_parent(struct clk *clk)
{
	if (!clk)
		return NULL;

	return clk->parent;
}
EXPORT_SYMBOL(clk_get_parent);

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int clk_register(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return -EINVAL;

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	if (WARN(clk->parent && !clk->parent->rate,
			"CLK: %s parent %s has no rate!\n",
			clk->name, clk->parent->name))
		return -EINVAL;

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	INIT_LIST_HEAD(&clk->children);

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	mutex_lock(&clocks_mutex);
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	list_add_tail(&clk->node, &clocks);
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	if (clk->parent) {
		if (clk->set_parent) {
			int ret = clk->set_parent(clk, clk->parent);

			if (ret) {
				mutex_unlock(&clocks_mutex);
				return ret;
			}
		}
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		list_add_tail(&clk->childnode, &clk->parent->children);
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	}
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	mutex_unlock(&clocks_mutex);

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	/* If rate is already set, use it */
	if (clk->rate)
		return 0;

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	/* Else, see if there is a way to calculate it */
	if (clk->recalc)
		clk->rate = clk->recalc(clk);

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	/* Otherwise, default to parent rate */
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	else if (clk->parent)
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		clk->rate = clk->parent->rate;

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	return 0;
}
EXPORT_SYMBOL(clk_register);

void clk_unregister(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return;

	mutex_lock(&clocks_mutex);
	list_del(&clk->node);
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	list_del(&clk->childnode);
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	mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);

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#ifdef CONFIG_DAVINCI_RESET_CLOCKS
/*
 * Disable any unused clocks left on by the bootloader
 */
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int __init davinci_clk_disable_unused(void)
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{
	struct clk *ck;

	spin_lock_irq(&clockfw_lock);
	list_for_each_entry(ck, &clocks, node) {
		if (ck->usecount > 0)
			continue;
		if (!(ck->flags & CLK_PSC))
			continue;

		/* ignore if in Disabled or SwRstDisable states */
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		if (!davinci_psc_is_clk_active(ck->gpsc, ck->lpsc))
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			continue;

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		pr_debug("Clocks: disable unused %s\n", ck->name);
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		davinci_psc_config(ck->domain, ck->gpsc, ck->lpsc,
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				false, ck->flags);
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	}
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	spin_unlock_irq(&clockfw_lock);

	return 0;
}
#endif
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static unsigned long clk_sysclk_recalc(struct clk *clk)
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{
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	u32 v, plldiv;
	struct pll_data *pll;
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	unsigned long rate = clk->rate;
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	/* If this is the PLL base clock, no more calculations needed */
	if (clk->pll_data)
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		return rate;
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	if (WARN_ON(!clk->parent))
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		return rate;
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	rate = clk->parent->rate;
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	/* Otherwise, the parent must be a PLL */
	if (WARN_ON(!clk->parent->pll_data))
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		return rate;
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	pll = clk->parent->pll_data;

	/* If pre-PLL, source clock is before the multiplier and divider(s) */
	if (clk->flags & PRE_PLL)
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		rate = pll->input_rate;
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	if (!clk->div_reg)
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		return rate;
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	v = __raw_readl(pll->base + clk->div_reg);
	if (v & PLLDIV_EN) {
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		plldiv = (v & pll->div_ratio_mask) + 1;
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		if (plldiv)
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			rate /= plldiv;
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	}
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	return rate;
}

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int davinci_set_sysclk_rate(struct clk *clk, unsigned long rate)
{
	unsigned v;
	struct pll_data *pll;
	unsigned long input;
	unsigned ratio = 0;

	/* If this is the PLL base clock, wrong function to call */
	if (clk->pll_data)
		return -EINVAL;

	/* There must be a parent... */
	if (WARN_ON(!clk->parent))
		return -EINVAL;

	/* ... the parent must be a PLL... */
	if (WARN_ON(!clk->parent->pll_data))
		return -EINVAL;

	/* ... and this clock must have a divider. */
	if (WARN_ON(!clk->div_reg))
		return -EINVAL;

	pll = clk->parent->pll_data;

	input = clk->parent->rate;

	/* If pre-PLL, source clock is before the multiplier and divider(s) */
	if (clk->flags & PRE_PLL)
		input = pll->input_rate;

	if (input > rate) {
		/*
		 * Can afford to provide an output little higher than requested
		 * only if maximum rate supported by hardware on this sysclk
		 * is known.
		 */
		if (clk->maxrate) {
			ratio = DIV_ROUND_CLOSEST(input, rate);
			if (input / ratio > clk->maxrate)
				ratio = 0;
		}

		if (ratio == 0)
			ratio = DIV_ROUND_UP(input, rate);

		ratio--;
	}

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	if (ratio > pll->div_ratio_mask)
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		return -EINVAL;

	do {
		v = __raw_readl(pll->base + PLLSTAT);
	} while (v & PLLSTAT_GOSTAT);

	v = __raw_readl(pll->base + clk->div_reg);
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	v &= ~pll->div_ratio_mask;
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	v |= ratio | PLLDIV_EN;
	__raw_writel(v, pll->base + clk->div_reg);

	v = __raw_readl(pll->base + PLLCMD);
	v |= PLLCMD_GOSET;
	__raw_writel(v, pll->base + PLLCMD);

	do {
		v = __raw_readl(pll->base + PLLSTAT);
	} while (v & PLLSTAT_GOSTAT);

	return 0;
}
EXPORT_SYMBOL(davinci_set_sysclk_rate);

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static unsigned long clk_leafclk_recalc(struct clk *clk)
{
	if (WARN_ON(!clk->parent))
		return clk->rate;

	return clk->parent->rate;
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}

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int davinci_simple_set_rate(struct clk *clk, unsigned long rate)
{
	clk->rate = rate;
	return 0;
}

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static unsigned long clk_pllclk_recalc(struct clk *clk)
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{
	u32 ctrl, mult = 1, prediv = 1, postdiv = 1;
	u8 bypass;
	struct pll_data *pll = clk->pll_data;
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	unsigned long rate = clk->rate;
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	ctrl = __raw_readl(pll->base + PLLCTL);
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	rate = pll->input_rate = clk->parent->rate;
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	if (ctrl & PLLCTL_PLLEN) {
		bypass = 0;
		mult = __raw_readl(pll->base + PLLM);
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		if (cpu_is_davinci_dm365())
			mult = 2 * (mult & PLLM_PLLM_MASK);
		else
			mult = (mult & PLLM_PLLM_MASK) + 1;
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	} else
		bypass = 1;

	if (pll->flags & PLL_HAS_PREDIV) {
		prediv = __raw_readl(pll->base + PREDIV);
		if (prediv & PLLDIV_EN)
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			prediv = (prediv & pll->div_ratio_mask) + 1;
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		else
			prediv = 1;
	}

	/* pre-divider is fixed, but (some?) chips won't report that */
	if (cpu_is_davinci_dm355() && pll->num == 1)
		prediv = 8;

	if (pll->flags & PLL_HAS_POSTDIV) {
		postdiv = __raw_readl(pll->base + POSTDIV);
		if (postdiv & PLLDIV_EN)
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			postdiv = (postdiv & pll->div_ratio_mask) + 1;
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		else
			postdiv = 1;
	}

	if (!bypass) {
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		rate /= prediv;
		rate *= mult;
		rate /= postdiv;
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	}

	pr_debug("PLL%d: input = %lu MHz [ ",
		 pll->num, clk->parent->rate / 1000000);
	if (bypass)
		pr_debug("bypass ");
	if (prediv > 1)
		pr_debug("/ %d ", prediv);
	if (mult > 1)
		pr_debug("* %d ", mult);
	if (postdiv > 1)
		pr_debug("/ %d ", postdiv);
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	pr_debug("] --> %lu MHz output.\n", rate / 1000000);

	return rate;
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}

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/**
 * davinci_set_pllrate - set the output rate of a given PLL.
 *
 * Note: Currently tested to work with OMAP-L138 only.
 *
 * @pll: pll whose rate needs to be changed.
 * @prediv: The pre divider value. Passing 0 disables the pre-divider.
 * @pllm: The multiplier value. Passing 0 leads to multiply-by-one.
 * @postdiv: The post divider value. Passing 0 disables the post-divider.
 */
int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv,
					unsigned int mult, unsigned int postdiv)
{
	u32 ctrl;
	unsigned int locktime;
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	unsigned long flags;
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	if (pll->base == NULL)
		return -EINVAL;

	/*
	 *  PLL lock time required per OMAP-L138 datasheet is
	 * (2000 * prediv)/sqrt(pllm) OSCIN cycles. We approximate sqrt(pllm)
	 * as 4 and OSCIN cycle as 25 MHz.
	 */
	if (prediv) {
		locktime = ((2000 * prediv) / 100);
		prediv = (prediv - 1) | PLLDIV_EN;
	} else {
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		locktime = PLL_LOCK_TIME;
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	}
	if (postdiv)
		postdiv = (postdiv - 1) | PLLDIV_EN;
	if (mult)
		mult = mult - 1;

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	/* Protect against simultaneous calls to PLL setting seqeunce */
	spin_lock_irqsave(&clockfw_lock, flags);

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	ctrl = __raw_readl(pll->base + PLLCTL);

	/* Switch the PLL to bypass mode */
	ctrl &= ~(PLLCTL_PLLENSRC | PLLCTL_PLLEN);
	__raw_writel(ctrl, pll->base + PLLCTL);

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	udelay(PLL_BYPASS_TIME);
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	/* Reset and enable PLL */
	ctrl &= ~(PLLCTL_PLLRST | PLLCTL_PLLDIS);
	__raw_writel(ctrl, pll->base + PLLCTL);

	if (pll->flags & PLL_HAS_PREDIV)
		__raw_writel(prediv, pll->base + PREDIV);

	__raw_writel(mult, pll->base + PLLM);

	if (pll->flags & PLL_HAS_POSTDIV)
		__raw_writel(postdiv, pll->base + POSTDIV);

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	udelay(PLL_RESET_TIME);
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	/* Bring PLL out of reset */
	ctrl |= PLLCTL_PLLRST;
	__raw_writel(ctrl, pll->base + PLLCTL);

	udelay(locktime);

	/* Remove PLL from bypass mode */
	ctrl |= PLLCTL_PLLEN;
	__raw_writel(ctrl, pll->base + PLLCTL);

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	spin_unlock_irqrestore(&clockfw_lock, flags);

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	return 0;
}
EXPORT_SYMBOL(davinci_set_pllrate);

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/**
 * davinci_set_refclk_rate() - Set the reference clock rate
 * @rate:	The new rate.
 *
 * Sets the reference clock rate to a given value. This will most likely
 * result in the entire clock tree getting updated.
 *
 * This is used to support boards which use a reference clock different
 * than that used by default in <soc>.c file. The reference clock rate
 * should be updated early in the boot process; ideally soon after the
 * clock tree has been initialized once with the default reference clock
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 * rate (davinci_clk_init()).
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 *
 * Returns 0 on success, error otherwise.
 */
int davinci_set_refclk_rate(unsigned long rate)
{
	struct clk *refclk;

	refclk = clk_get(NULL, "ref");
	if (IS_ERR(refclk)) {
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		pr_err("%s: failed to get reference clock\n", __func__);
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		return PTR_ERR(refclk);
	}

	clk_set_rate(refclk, rate);

	clk_put(refclk);

	return 0;
}

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int __init davinci_clk_init(struct clk_lookup *clocks)
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{
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	struct clk_lookup *c;
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	struct clk *clk;
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	size_t num_clocks = 0;
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	for (c = clocks; c->clk; c++) {
		clk = c->clk;
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		if (!clk->recalc) {

			/* Check if clock is a PLL */
			if (clk->pll_data)
				clk->recalc = clk_pllclk_recalc;

			/* Else, if it is a PLL-derived clock */
			else if (clk->flags & CLK_PLL)
				clk->recalc = clk_sysclk_recalc;

			/* Otherwise, it is a leaf clock (PSC clock) */
			else if (clk->parent)
				clk->recalc = clk_leafclk_recalc;
		}
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		if (clk->pll_data) {
			struct pll_data *pll = clk->pll_data;

			if (!pll->div_ratio_mask)
				pll->div_ratio_mask = PLLDIV_RATIO_MASK;

			if (pll->phys_base && !pll->base) {
				pll->base = ioremap(pll->phys_base, SZ_4K);
				WARN_ON(!pll->base);
			}
		}
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		if (clk->recalc)
			clk->rate = clk->recalc(clk);
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		if (clk->lpsc)
			clk->flags |= CLK_PSC;

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		if (clk->flags & PSC_LRST)
			clk->reset = davinci_clk_reset;

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		clk_register(clk);
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		num_clocks++;
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		/* Turn on clocks that Linux doesn't otherwise manage */
		if (clk->flags & ALWAYS_ENABLED)
			clk_enable(clk);
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	}

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	clkdev_add_table(clocks, num_clocks);

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	return 0;
}

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#ifdef CONFIG_DEBUG_FS
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#include <linux/debugfs.h>
#include <linux/seq_file.h>
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#define CLKNAME_MAX	10		/* longest clock name */
#define NEST_DELTA	2
#define NEST_MAX	4

static void
dump_clock(struct seq_file *s, unsigned nest, struct clk *parent)
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{
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	char		*state;
	char		buf[CLKNAME_MAX + NEST_DELTA * NEST_MAX];
	struct clk	*clk;
	unsigned	i;

	if (parent->flags & CLK_PLL)
		state = "pll";
	else if (parent->flags & CLK_PSC)
		state = "psc";
	else
		state = "";

	/* <nest spaces> name <pad to end> */
	memset(buf, ' ', sizeof(buf) - 1);
	buf[sizeof(buf) - 1] = 0;
	i = strlen(parent->name);
	memcpy(buf + nest, parent->name,
			min(i, (unsigned)(sizeof(buf) - 1 - nest)));

	seq_printf(s, "%s users=%2d %-3s %9ld Hz\n",
		   buf, parent->usecount, state, clk_get_rate(parent));
	/* REVISIT show device associations too */

	/* cost is now small, but not linear... */
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	list_for_each_entry(clk, &parent->children, childnode) {
		dump_clock(s, nest + NEST_DELTA, clk);
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	}
}
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static int davinci_ck_show(struct seq_file *m, void *v)
{
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	struct clk *clk;

	/*
	 * Show clock tree; We trust nonzero usecounts equate to PSC enables...
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	 */
	mutex_lock(&clocks_mutex);
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	list_for_each_entry(clk, &clocks, node)
		if (!clk->parent)
			dump_clock(m, 0, clk);
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	mutex_unlock(&clocks_mutex);
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	return 0;
}

static int davinci_ck_open(struct inode *inode, struct file *file)
{
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	return single_open(file, davinci_ck_show, NULL);
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}

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static const struct file_operations davinci_ck_operations = {
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	.open		= davinci_ck_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
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	.release	= single_release,
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};

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static int __init davinci_clk_debugfs_init(void)
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{
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	debugfs_create_file("davinci_clocks", S_IFREG | S_IRUGO, NULL, NULL,
						&davinci_ck_operations);
741 742 743
	return 0;

}
744 745
device_initcall(davinci_clk_debugfs_init);
#endif /* CONFIG_DEBUG_FS */