linux/arch/arm/mach-davinci/clock.c

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/*
* 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/platform_device.h>
#include <linux/io.h>
#include <mach/hardware.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 unsigned psc_domain(struct clk *clk)
{
return (clk->flags & PSC_DSP)
? DAVINCI_GPSC_DSPDOMAIN
: DAVINCI_GPSC_ARMDOMAIN;
}
static void __clk_enable(struct clk *clk)
{
if (clk->parent)
__clk_enable(clk->parent);
if (clk->usecount++ == 0 && (clk->flags & CLK_PSC))
davinci_psc_config(psc_domain(clk), clk->psc_ctlr,
clk->lpsc, 1);
}
static void __clk_disable(struct clk *clk)
{
if (WARN_ON(clk->usecount == 0))
return;
if (--clk->usecount == 0 && !(clk->flags & CLK_PLL))
davinci_psc_config(psc_domain(clk), clk->psc_ctlr,
clk->lpsc, 0);
if (clk->parent)
__clk_disable(clk->parent);
}
int clk_enable(struct clk *clk)
{
unsigned long flags;
if (clk == NULL || 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 -EINVAL;
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 -EINVAL;
return clk->rate;
}
EXPORT_SYMBOL(clk_round_rate);
int clk_set_rate(struct clk *clk, unsigned long rate)
{
if (clk == NULL || IS_ERR(clk))
return -EINVAL;
/* changing the clk rate is not supported */
return -EINVAL;
}
EXPORT_SYMBOL(clk_set_rate);
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;
mutex_lock(&clocks_mutex);
list_add_tail(&clk->node, &clocks);
mutex_unlock(&clocks_mutex);
/* If rate is already set, use it */
if (clk->rate)
return 0;
/* Otherwise, default to parent rate */
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);
mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);
#ifdef CONFIG_DAVINCI_RESET_CLOCKS
/*
* Disable any unused clocks left on by the bootloader
*/
static int __init 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->psc_ctlr, ck->lpsc))
continue;
pr_info("Clocks: disable unused %s\n", ck->name);
davinci_psc_config(psc_domain(ck), ck->psc_ctlr, ck->lpsc, 0);
}
spin_unlock_irq(&clockfw_lock);
return 0;
}
late_initcall(clk_disable_unused);
#endif
static void clk_sysclk_recalc(struct clk *clk)
{
u32 v, plldiv;
struct pll_data *pll;
/* If this is the PLL base clock, no more calculations needed */
if (clk->pll_data)
return;
if (WARN_ON(!clk->parent))
return;
clk->rate = clk->parent->rate;
/* Otherwise, the parent must be a PLL */
if (WARN_ON(!clk->parent->pll_data))
return;
pll = clk->parent->pll_data;
/* If pre-PLL, source clock is before the multiplier and divider(s) */
if (clk->flags & PRE_PLL)
clk->rate = pll->input_rate;
if (!clk->div_reg)
return;
v = __raw_readl(pll->base + clk->div_reg);
if (v & PLLDIV_EN) {
plldiv = (v & PLLDIV_RATIO_MASK) + 1;
if (plldiv)
clk->rate /= plldiv;
}
}
static void __init clk_pll_init(struct clk *clk)
{
u32 ctrl, mult = 1, prediv = 1, postdiv = 1;
u8 bypass;
struct pll_data *pll = clk->pll_data;
pll->base = IO_ADDRESS(pll->phys_base);
ctrl = __raw_readl(pll->base + PLLCTL);
clk->rate = pll->input_rate = clk->parent->rate;
if (ctrl & PLLCTL_PLLEN) {
bypass = 0;
mult = __raw_readl(pll->base + PLLM);
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 & PLLDIV_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 & PLLDIV_RATIO_MASK) + 1;
else
postdiv = 1;
}
if (!bypass) {
clk->rate /= prediv;
clk->rate *= mult;
clk->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", clk->rate / 1000000);
}
int __init davinci_clk_init(struct davinci_clk *clocks)
{
struct davinci_clk *c;
struct clk *clk;
for (c = clocks; c->lk.clk; c++) {
clk = c->lk.clk;
if (clk->pll_data)
clk_pll_init(clk);
/* Calculate rates for PLL-derived clocks */
else if (clk->flags & CLK_PLL)
clk_sysclk_recalc(clk);
if (clk->lpsc)
clk->flags |= CLK_PSC;
clkdev_add(&c->lk);
clk_register(clk);
/* Turn on clocks that Linux doesn't otherwise manage */
if (clk->flags & ALWAYS_ENABLED)
clk_enable(clk);
}
return 0;
}
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
static void *davinci_ck_start(struct seq_file *m, loff_t *pos)
{
return *pos < 1 ? (void *)1 : NULL;
}
static void *davinci_ck_next(struct seq_file *m, void *v, loff_t *pos)
{
++*pos;
return NULL;
}
static void davinci_ck_stop(struct seq_file *m, void *v)
{
}
#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, &clocks, node) {
if (clk->parent == parent)
dump_clock(s, nest + NEST_DELTA, clk);
}
}
static int davinci_ck_show(struct seq_file *m, void *v)
{
/* Show clock tree; we know the main oscillator is first.
* We trust nonzero usecounts equate to PSC enables...
*/
mutex_lock(&clocks_mutex);
if (!list_empty(&clocks))
dump_clock(m, 0, list_first_entry(&clocks, struct clk, node));
mutex_unlock(&clocks_mutex);
return 0;
}
static const struct seq_operations davinci_ck_op = {
.start = davinci_ck_start,
.next = davinci_ck_next,
.stop = davinci_ck_stop,
.show = davinci_ck_show
};
static int davinci_ck_open(struct inode *inode, struct file *file)
{
return seq_open(file, &davinci_ck_op);
}
static const struct file_operations proc_davinci_ck_operations = {
.open = davinci_ck_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init davinci_ck_proc_init(void)
{
proc_create("davinci_clocks", 0, NULL, &proc_davinci_ck_operations);
return 0;
}
__initcall(davinci_ck_proc_init);
#endif /* CONFIG_DEBUG_PROC_FS */