- 根目录:
- arch
- arm
- mach-davinci
- clock.c
/*
* Clock and PLL control for DaVinci devices
*
* Copyright (C) 2006-2007 Texas Instruments.
* Copyright (C) 2008-2009 Deep Root Systems, LLC
*
* 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>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <mach/hardware.h>
#include <mach/clock.h>
#include <mach/psc.h>
#include <mach/cputype.h>
#include "clock.h"
static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
static DEFINE_SPINLOCK(clockfw_lock);
static void __clk_enable(struct clk *clk)
{
if (clk->parent)
__clk_enable(clk->parent);
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);
}
}
static void __clk_disable(struct clk *clk)
{
if (WARN_ON(clk->usecount == 0))
return;
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);
}
if (clk->parent)
__clk_disable(clk->parent);
}
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);
int clk_enable(struct clk *clk)
{
unsigned long flags;
if (!clk)
return 0;
else if (IS_ERR(clk))
return -EINVAL;
spin_lock_irqsave(&clockfw_lock, flags);
__clk_enable(clk);
spin_unlock_irqrestore(&clockfw_lock, flags);
return 0;
}
EXPORT_SYMBOL(clk_enable);
void clk_disable(struct clk *clk)
{
unsigned long flags;
if (clk == NULL || IS_ERR(clk))
return;
spin_lock_irqsave(&clockfw_lock, flags);
__clk_disable(clk);
spin_unlock_irqrestore(&clockfw_lock, flags);
}
EXPORT_SYMBOL(clk_disable);
unsigned long clk_get_rate(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return 0;
return clk->rate;
}
EXPORT_SYMBOL(clk_get_rate);
long clk_round_rate(struct clk *clk, unsigned long rate)
{
if (clk == NULL || IS_ERR(clk))
return 0;
if (clk->round_rate)
return clk->round_rate(clk, rate);
return clk->rate;
}
EXPORT_SYMBOL(clk_round_rate);
/* 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);
}
}
int clk_set_rate(struct clk *clk, unsigned long rate)
{
unsigned long flags;
int ret = -EINVAL;
if (!clk)
return 0;
else if (IS_ERR(clk))
return -EINVAL;
if (clk->set_rate)
ret = clk->set_rate(clk, rate);
spin_lock_irqsave(&clockfw_lock, flags);
if (ret == 0) {
if (clk->recalc)
clk->rate = clk->recalc(clk);
propagate_rate(clk);
}
spin_unlock_irqrestore(&clockfw_lock, flags);
return ret;
}
EXPORT_SYMBOL(clk_set_rate);
int clk_set_parent(struct clk *clk, struct clk *parent)
{
unsigned long flags;
if (!clk)
return 0;
else if (IS_ERR(clk))
return -EINVAL;
/* Cannot change parent on enabled clock */
if (WARN_ON(clk->usecount))
return -EINVAL;
mutex_lock(&clocks_mutex);
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);
int clk_register(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return -EINVAL;
if (WARN(clk->parent && !clk->parent->rate,
"CLK: %s parent %s has no rate!\n",
clk->name, clk->parent->name))
return -EINVAL;
INIT_LIST_HEAD(&clk->children);
mutex_lock(&clocks_mutex);
list_add_tail(&clk->node, &clocks);
if (clk->parent)
list_add_tail(&clk->childnode, &clk->parent->children);
mutex_unlock(&clocks_mutex);
/* If rate is already set, use it */
if (clk->rate)
return 0;
/* Else, see if there is a way to calculate it */
if (clk->recalc)
clk->rate = clk->recalc(clk);
/* Otherwise, default to parent rate */
else if (clk->parent)
clk->rate = clk->parent->rate;
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);
list_del(&clk->childnode);
mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);
#ifdef CONFIG_DAVINCI_RESET_CLOCKS
/*
* Disable any unused clocks left on by the bootloader
*/
int __init davinci_clk_disable_unused(void)
{
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 */
if (!davinci_psc_is_clk_active(ck->gpsc, ck->lpsc))
continue;
pr_debug("Clocks: disable unused %s\n", ck->name);
davinci_psc_config(ck->domain, ck->gpsc, ck->lpsc,
false, ck->flags);
}
spin_unlock_irq(&clockfw_lock);
return 0;
}
#endif
static unsigned long clk_sysclk_recalc(struct clk *clk)
{
u32 v, plldiv;
struct pll_data *pll;
unsigned long rate = clk->rate;
/* If this is the PLL base clock, no more calculations needed */
if (clk->pll_data)
return rate;
if (WARN_ON(!clk->parent))
return rate;
rate = clk->parent->rate;
/* Otherwise, the parent must be a PLL */
if (WARN_ON(!clk->parent->pll_data))
return rate;
pll = clk->parent->pll_data;
/* If pre-PLL, source clock is before the multiplier and divider(s) */
if (clk->flags & PRE_PLL)
rate = pll->input_rate;
if (!clk->div_reg)
return rate;
v = __raw_readl(pll->base + clk->div_reg);
if (v & PLLDIV_EN) {
plldiv = (v & pll->div_ratio_mask) + 1;
if (plldiv)
rate /= plldiv;
}
return rate;
}
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--;
}
if (ratio > pll->div_ratio_mask)
return -EINVAL;
do {
v = __raw_readl(pll->base + PLLSTAT);
} while (v & PLLSTAT_GOSTAT);
v = __raw_readl(pll->base + clk->div_reg);
v &= ~pll->div_ratio_mask;
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);
static unsigned long clk_leafclk_recalc(struct clk *clk)
{
if (WARN_ON(!clk->parent))
return clk->rate;
return clk->parent->rate;
}
int davinci_simple_set_rate(struct clk *clk, unsigned long rate)
{
clk->rate = rate;
return 0;
}
static unsigned long clk_pllclk_recalc(struct clk *clk)
{
u32 ctrl, mult = 1, prediv = 1, postdiv = 1;
u8 bypass;
struct pll_data *pll = clk->pll_data;
unsigned long rate = clk->rate;
ctrl = __raw_readl(pll->base + PLLCTL);
rate = pll->input_rate = clk->parent->rate;
if (ctrl & PLLCTL_PLLEN) {
bypass = 0;
mult = __raw_readl(pll->base + PLLM);
if (cpu_is_davinci_dm365())
mult = 2 * (mult & PLLM_PLLM_MASK);
else
mult = (mult & PLLM_PLLM_MASK) + 1;
} else
bypass = 1;
if (pll->flags & PLL_HAS_PREDIV) {
prediv = __raw_readl(pll->base + PREDIV);
if (prediv & PLLDIV_EN)
prediv = (prediv & pll->div_ratio_mask) + 1;
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)
postdiv = (postdiv & pll->div_ratio_mask) + 1;
else
postdiv = 1;
}
if (!bypass) {
rate /= prediv;
rate *= mult;
rate /= postdiv;
}
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);
pr_debug("] --> %lu MHz output.\n", rate / 1000000);
return rate;
}
/**
* 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;
unsigned long flags;
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 {
locktime = PLL_LOCK_TIME;
}
if (postdiv)
postdiv = (postdiv - 1) | PLLDIV_EN;
if (mult)
mult = mult - 1;
/* Protect against simultaneous calls to PLL setting seqeunce */
spin_lock_irqsave(&clockfw_lock, flags);
ctrl = __raw_readl(pll->base + PLLCTL);
/* Switch the PLL to bypass mode */
ctrl &= ~(PLLCTL_PLLENSRC | PLLCTL_PLLEN);
__raw_writel(ctrl, pll->base + PLLCTL);
udelay(PLL_BYPASS_TIME);
/* 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);
udelay(PLL_RESET_TIME);
/* 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);
spin_unlock_irqrestore(&clockfw_lock, flags);
return 0;
}
EXPORT_SYMBOL(davinci_set_pllrate);
/**
* 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
* rate (davinci_common_init()).
*
* 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)) {
pr_err("%s: failed to get reference clock\n", __func__);
return PTR_ERR(refclk);
}
clk_set_rate(refclk, rate);
clk_put(refclk);
return 0;
}
int __init davinci_clk_init(struct clk_lookup *clocks)
{
struct clk_lookup *c;
struct clk *clk;
size_t num_clocks = 0;
for (c = clocks; c->clk; c++) {
clk = c->clk;
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;
}
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);
}
}
if (clk->recalc)
clk->rate = clk->recalc(clk);
if (clk->lpsc)
clk->flags |= CLK_PSC;
if (clk->flags & PSC_LRST)
clk->reset = davinci_clk_reset;
clk_register(clk);
num_clocks++;
/* Turn on clocks that Linux doesn't otherwise manage */
if (clk->flags & ALWAYS_ENABLED)
clk_enable(clk);
}
clkdev_add_table(clocks, num_clocks);
return 0;
}
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#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)
{
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... */
list_for_each_entry(clk, &parent->children, childnode) {
dump_clock(s, nest + NEST_DELTA, clk);
}
}
static int davinci_ck_show(struct seq_file *m, void *v)
{
struct clk *clk;
/*
* Show clock tree; We trust nonzero usecounts equate to PSC enables...
*/
mutex_lock(&clocks_mutex);
list_for_each_entry(clk, &clocks, node)
if (!clk->parent)
dump_clock(m, 0, clk);
mutex_unlock(&clocks_mutex);
return 0;
}
static int davinci_ck_open(struct inode *inode, struct file *file)
{
return single_open(file, davinci_ck_show, NULL);
}
static const struct file_operations davinci_ck_operations = {
.open = davinci_ck_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init davinci_clk_debugfs_init(void)
{
debugfs_create_file("davinci_clocks", S_IFREG | S_IRUGO, NULL, NULL,
&davinci_ck_operations);
return 0;
}
device_initcall(davinci_clk_debugfs_init);
#endif /* CONFIG_DEBUG_FS */