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/* arch/arm/mach-msm/clock.c
*
* Copyright (C) 2007 Google, Inc.
* Copyright (c) 2007-2012, Code Aurora Forum. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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/kernel.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <trace/events/power.h>
#include "clock.h"
/* Find the voltage level required for a given rate. */
static int find_vdd_level(struct clk *clk, unsigned long rate)
{
int level;
for (level = 0; level < ARRAY_SIZE(clk->fmax); level++)
if (rate <= clk->fmax[level])
break;
if (level == ARRAY_SIZE(clk->fmax)) {
pr_err("Rate %lu for %s is greater than highest Fmax\n", rate,
clk->dbg_name);
return -EINVAL;
}
return level;
}
/* Update voltage level given the current votes. */
static int update_vdd(struct clk_vdd_class *vdd_class)
{
int level, rc;
for (level = ARRAY_SIZE(vdd_class->level_votes)-1; level > 0; level--)
if (vdd_class->level_votes[level])
break;
if (level == vdd_class->cur_level)
return 0;
rc = vdd_class->set_vdd(vdd_class, level);
if (!rc)
vdd_class->cur_level = level;
return rc;
}
/* Vote for a voltage level. */
int vote_vdd_level(struct clk_vdd_class *vdd_class, int level)
{
unsigned long flags;
int rc;
spin_lock_irqsave(&vdd_class->lock, flags);
vdd_class->level_votes[level]++;
rc = update_vdd(vdd_class);
if (rc)
vdd_class->level_votes[level]--;
spin_unlock_irqrestore(&vdd_class->lock, flags);
return rc;
}
/* Remove vote for a voltage level. */
int unvote_vdd_level(struct clk_vdd_class *vdd_class, int level)
{
unsigned long flags;
int rc = 0;
spin_lock_irqsave(&vdd_class->lock, flags);
if (WARN(!vdd_class->level_votes[level],
"Reference counts are incorrect for %s level %d\n",
vdd_class->class_name, level))
goto out;
vdd_class->level_votes[level]--;
rc = update_vdd(vdd_class);
if (rc)
vdd_class->level_votes[level]++;
out:
spin_unlock_irqrestore(&vdd_class->lock, flags);
return rc;
}
/* Vote for a voltage level corresponding to a clock's rate. */
static int vote_rate_vdd(struct clk *clk, unsigned long rate)
{
int level;
if (!clk->vdd_class)
return 0;
level = find_vdd_level(clk, rate);
if (level < 0)
return level;
return vote_vdd_level(clk->vdd_class, level);
}
/* Remove vote for a voltage level corresponding to a clock's rate. */
static void unvote_rate_vdd(struct clk *clk, unsigned long rate)
{
int level;
if (!clk->vdd_class)
return;
level = find_vdd_level(clk, rate);
if (level < 0)
return;
unvote_vdd_level(clk->vdd_class, level);
}
int clk_prepare(struct clk *clk)
{
int ret = 0;
struct clk *parent;
if (!clk)
return 0;
if (IS_ERR(clk))
return -EINVAL;
mutex_lock(&clk->prepare_lock);
if (clk->prepare_count == 0) {
parent = clk_get_parent(clk);
ret = clk_prepare(parent);
if (ret)
goto out;
ret = clk_prepare(clk->depends);
if (ret)
goto err_prepare_depends;
if (clk->ops->prepare)
ret = clk->ops->prepare(clk);
if (ret)
goto err_prepare_clock;
}
clk->prepare_count++;
out:
mutex_unlock(&clk->prepare_lock);
return ret;
err_prepare_clock:
clk_unprepare(clk->depends);
err_prepare_depends:
clk_unprepare(parent);
goto out;
}
EXPORT_SYMBOL(clk_prepare);
/*
* Standard clock functions defined in include/linux/clk.h
*/
int clk_enable(struct clk *clk)
{
int ret = 0;
unsigned long flags;
struct clk *parent;
if (!clk)
return 0;
if (IS_ERR(clk))
return -EINVAL;
spin_lock_irqsave(&clk->lock, flags);
if (WARN(!clk->warned && !clk->prepare_count,
"%s: Don't call enable on unprepared clocks\n",
clk->dbg_name))
clk->warned = true;
if (clk->count == 0) {
parent = clk_get_parent(clk);
ret = clk_enable(parent);
if (ret)
goto err_enable_parent;
ret = clk_enable(clk->depends);
if (ret)
goto err_enable_depends;
ret = vote_rate_vdd(clk, clk->rate);
if (ret)
goto err_vote_vdd;
trace_clock_enable(clk->dbg_name, 1, smp_processor_id());
if (clk->ops->enable)
ret = clk->ops->enable(clk);
if (ret)
goto err_enable_clock;
} else if (clk->flags & CLKFLAG_HANDOFF_RATE) {
/*
* The clock was already enabled by handoff code so there is no
* need to enable it again here. Clearing the handoff flag will
* prevent the lateinit handoff code from disabling the clock if
* a client driver still has it enabled.
*/
clk->flags &= ~CLKFLAG_HANDOFF_RATE;
goto out;
}
clk->count++;
out:
spin_unlock_irqrestore(&clk->lock, flags);
return 0;
err_enable_clock:
unvote_rate_vdd(clk, clk->rate);
err_vote_vdd:
clk_disable(clk->depends);
err_enable_depends:
clk_disable(parent);
err_enable_parent:
spin_unlock_irqrestore(&clk->lock, flags);
return ret;
}
EXPORT_SYMBOL(clk_enable);
void clk_disable(struct clk *clk)
{
unsigned long flags;
if (IS_ERR_OR_NULL(clk))
return;
spin_lock_irqsave(&clk->lock, flags);
if (WARN(!clk->warned && !clk->prepare_count,
"%s: Never called prepare or calling disable "
"after unprepare\n",
clk->dbg_name))
clk->warned = true;
if (WARN(clk->count == 0, "%s is unbalanced", clk->dbg_name))
goto out;
if (clk->count == 1) {
struct clk *parent = clk_get_parent(clk);
trace_clock_disable(clk->dbg_name, 0, smp_processor_id());
if (clk->ops->disable)
clk->ops->disable(clk);
unvote_rate_vdd(clk, clk->rate);
clk_disable(clk->depends);
clk_disable(parent);
}
clk->count--;
out:
spin_unlock_irqrestore(&clk->lock, flags);
}
EXPORT_SYMBOL(clk_disable);
void clk_unprepare(struct clk *clk)
{
if (IS_ERR_OR_NULL(clk))
return;
mutex_lock(&clk->prepare_lock);
if (!clk->prepare_count) {
if (WARN(!clk->warned, "%s is unbalanced (prepare)",
clk->dbg_name))
clk->warned = true;
goto out;
}
if (clk->prepare_count == 1) {
struct clk *parent = clk_get_parent(clk);
if (WARN(!clk->warned && clk->count,
"%s: Don't call unprepare when the clock is enabled\n",
clk->dbg_name))
clk->warned = true;
if (clk->ops->unprepare)
clk->ops->unprepare(clk);
clk_unprepare(clk->depends);
clk_unprepare(parent);
}
clk->prepare_count--;
out:
mutex_unlock(&clk->prepare_lock);
}
EXPORT_SYMBOL(clk_unprepare);
int clk_reset(struct clk *clk, enum clk_reset_action action)
{
if (IS_ERR_OR_NULL(clk))
return -EINVAL;
if (!clk->ops->reset)
return -ENOSYS;
return clk->ops->reset(clk, action);
}
EXPORT_SYMBOL(clk_reset);
unsigned long clk_get_rate(struct clk *clk)
{
if (IS_ERR_OR_NULL(clk))
return 0;
if (!clk->ops->get_rate)
return clk->rate;
return clk->ops->get_rate(clk);
}
EXPORT_SYMBOL(clk_get_rate);
int clk_set_rate(struct clk *clk, unsigned long rate)
{
unsigned long start_rate, flags;
int rc;
if (IS_ERR_OR_NULL(clk))
return -EINVAL;
if (!clk->ops->set_rate)
return -ENOSYS;
spin_lock_irqsave(&clk->lock, flags);
trace_clock_set_rate(clk->dbg_name, rate, smp_processor_id());
if (clk->count) {
start_rate = clk->rate;
/* Enforce vdd requirements for target frequency. */
rc = vote_rate_vdd(clk, rate);
if (rc)
goto err_vote_vdd;
rc = clk->ops->set_rate(clk, rate);
if (rc)
goto err_set_rate;
/* Release vdd requirements for starting frequency. */
unvote_rate_vdd(clk, start_rate);
} else {
rc = clk->ops->set_rate(clk, rate);
}
if (!rc)
clk->rate = rate;
spin_unlock_irqrestore(&clk->lock, flags);
return rc;
err_set_rate:
unvote_rate_vdd(clk, rate);
err_vote_vdd:
spin_unlock_irqrestore(&clk->lock, flags);
return rc;
}
EXPORT_SYMBOL(clk_set_rate);
long clk_round_rate(struct clk *clk, unsigned long rate)
{
if (IS_ERR_OR_NULL(clk))
return -EINVAL;
if (!clk->ops->round_rate)
return -ENOSYS;
return clk->ops->round_rate(clk, rate);
}
EXPORT_SYMBOL(clk_round_rate);
int clk_set_max_rate(struct clk *clk, unsigned long rate)
{
if (IS_ERR_OR_NULL(clk))
return -EINVAL;
if (!clk->ops->set_max_rate)
return -ENOSYS;
return clk->ops->set_max_rate(clk, rate);
}
EXPORT_SYMBOL(clk_set_max_rate);
int clk_set_parent(struct clk *clk, struct clk *parent)
{
if (!clk->ops->set_parent)
return 0;
return clk->ops->set_parent(clk, parent);
}
EXPORT_SYMBOL(clk_set_parent);
struct clk *clk_get_parent(struct clk *clk)
{
if (IS_ERR_OR_NULL(clk))
return NULL;
if (!clk->ops->get_parent)
return NULL;
return clk->ops->get_parent(clk);
}
EXPORT_SYMBOL(clk_get_parent);
int clk_set_flags(struct clk *clk, unsigned long flags)
{
if (IS_ERR_OR_NULL(clk))
return -EINVAL;
if (!clk->ops->set_flags)
return -ENOSYS;
return clk->ops->set_flags(clk, flags);
}
EXPORT_SYMBOL(clk_set_flags);
static struct clock_init_data __initdata *clk_init_data;
void __init msm_clock_init(struct clock_init_data *data)
{
unsigned n;
struct clk_lookup *clock_tbl;
size_t num_clocks;
struct clk *clk;
clk_init_data = data;
if (clk_init_data->pre_init)
clk_init_data->pre_init();
clock_tbl = data->table;
num_clocks = data->size;
for (n = 0; n < num_clocks; n++) {
struct clk *parent;
clk = clock_tbl[n].clk;
parent = clk_get_parent(clk);
if (parent && list_empty(&clk->siblings))
list_add(&clk->siblings, &parent->children);
}
/*
* Detect and preserve initial clock state until clock_late_init() or
* a driver explicitly changes it, whichever is first.
*/
for (n = 0; n < num_clocks; n++) {
clk = clock_tbl[n].clk;
if (clk->ops->handoff && !(clk->flags & CLKFLAG_HANDOFF_RATE) &&
(clk->ops->handoff(clk) == HANDOFF_ENABLED_CLK)) {
clk->flags |= CLKFLAG_HANDOFF_RATE;
clk_prepare_enable(clk);
}
}
clkdev_add_table(clock_tbl, num_clocks);
if (clk_init_data->post_init)
clk_init_data->post_init();
}
/*
* The bootloader and/or AMSS may have left various clocks enabled.
* Disable any clocks that have not been explicitly enabled by a
* clk_enable() call and don't have the CLKFLAG_SKIP_AUTO_OFF flag.
*/
static int __init clock_late_init(void)
{
unsigned n, count = 0;
unsigned long flags;
int ret = 0;
clock_debug_init(clk_init_data);
for (n = 0; n < clk_init_data->size; n++) {
struct clk *clk = clk_init_data->table[n].clk;
bool handoff = false;
clock_debug_add(clk);
spin_lock_irqsave(&clk->lock, flags);
if (!(clk->flags & CLKFLAG_SKIP_AUTO_OFF)) {
if (!clk->count && clk->ops->auto_off) {
count++;
clk->ops->auto_off(clk);
}
}
if (clk->flags & CLKFLAG_HANDOFF_RATE) {
clk->flags &= ~CLKFLAG_HANDOFF_RATE;
handoff = true;
}
spin_unlock_irqrestore(&clk->lock, flags);
/*
* Calling this outside the lock is safe since
* it doesn't need to be atomic with the flag change.
*/
if (handoff)
clk_disable_unprepare(clk);
}
pr_info("clock_late_init() disabled %d unused clocks\n", count);
if (clk_init_data->late_init)
ret = clk_init_data->late_init();
return ret;
}
late_initcall(clock_late_init);