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![Sylwester Nawrocki](/assets/img/avatar_default.png)
Ensure clk->kref is dereferenced only when clk is not NULL. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Tested-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2550 lines
61 KiB
C
2550 lines
61 KiB
C
/*
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* Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
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* Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Standard functionality for the common clock API. See Documentation/clk.txt
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*/
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#include <linux/clk-private.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/err.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include "clk.h"
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static DEFINE_SPINLOCK(enable_lock);
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static DEFINE_MUTEX(prepare_lock);
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static struct task_struct *prepare_owner;
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static struct task_struct *enable_owner;
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static int prepare_refcnt;
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static int enable_refcnt;
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static HLIST_HEAD(clk_root_list);
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static HLIST_HEAD(clk_orphan_list);
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static LIST_HEAD(clk_notifier_list);
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/*** locking ***/
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static void clk_prepare_lock(void)
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{
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if (!mutex_trylock(&prepare_lock)) {
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if (prepare_owner == current) {
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prepare_refcnt++;
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return;
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}
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mutex_lock(&prepare_lock);
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}
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WARN_ON_ONCE(prepare_owner != NULL);
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WARN_ON_ONCE(prepare_refcnt != 0);
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prepare_owner = current;
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prepare_refcnt = 1;
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}
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static void clk_prepare_unlock(void)
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{
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WARN_ON_ONCE(prepare_owner != current);
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WARN_ON_ONCE(prepare_refcnt == 0);
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if (--prepare_refcnt)
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return;
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prepare_owner = NULL;
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mutex_unlock(&prepare_lock);
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}
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static unsigned long clk_enable_lock(void)
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{
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unsigned long flags;
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if (!spin_trylock_irqsave(&enable_lock, flags)) {
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if (enable_owner == current) {
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enable_refcnt++;
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return flags;
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}
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spin_lock_irqsave(&enable_lock, flags);
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}
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WARN_ON_ONCE(enable_owner != NULL);
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WARN_ON_ONCE(enable_refcnt != 0);
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enable_owner = current;
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enable_refcnt = 1;
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return flags;
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}
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static void clk_enable_unlock(unsigned long flags)
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{
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WARN_ON_ONCE(enable_owner != current);
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WARN_ON_ONCE(enable_refcnt == 0);
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if (--enable_refcnt)
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return;
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enable_owner = NULL;
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spin_unlock_irqrestore(&enable_lock, flags);
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}
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/*** debugfs support ***/
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#ifdef CONFIG_DEBUG_FS
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#include <linux/debugfs.h>
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static struct dentry *rootdir;
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static struct dentry *orphandir;
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static int inited = 0;
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static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
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{
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if (!c)
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return;
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seq_printf(s, "%*s%-*s %-11d %-12d %-10lu %-11lu",
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level * 3 + 1, "",
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30 - level * 3, c->name,
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c->enable_count, c->prepare_count, clk_get_rate(c),
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clk_get_accuracy(c));
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seq_printf(s, "\n");
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}
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static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
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int level)
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{
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struct clk *child;
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if (!c)
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return;
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clk_summary_show_one(s, c, level);
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hlist_for_each_entry(child, &c->children, child_node)
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clk_summary_show_subtree(s, child, level + 1);
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}
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static int clk_summary_show(struct seq_file *s, void *data)
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{
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struct clk *c;
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seq_printf(s, " clock enable_cnt prepare_cnt rate accuracy\n");
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seq_printf(s, "---------------------------------------------------------------------------------\n");
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clk_prepare_lock();
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hlist_for_each_entry(c, &clk_root_list, child_node)
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clk_summary_show_subtree(s, c, 0);
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hlist_for_each_entry(c, &clk_orphan_list, child_node)
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clk_summary_show_subtree(s, c, 0);
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clk_prepare_unlock();
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return 0;
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}
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static int clk_summary_open(struct inode *inode, struct file *file)
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{
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return single_open(file, clk_summary_show, inode->i_private);
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}
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static const struct file_operations clk_summary_fops = {
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.open = clk_summary_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
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{
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if (!c)
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return;
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seq_printf(s, "\"%s\": { ", c->name);
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seq_printf(s, "\"enable_count\": %d,", c->enable_count);
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seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
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seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
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seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
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}
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static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
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{
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struct clk *child;
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if (!c)
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return;
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clk_dump_one(s, c, level);
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hlist_for_each_entry(child, &c->children, child_node) {
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seq_printf(s, ",");
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clk_dump_subtree(s, child, level + 1);
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}
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seq_printf(s, "}");
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}
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static int clk_dump(struct seq_file *s, void *data)
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{
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struct clk *c;
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bool first_node = true;
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seq_printf(s, "{");
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clk_prepare_lock();
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hlist_for_each_entry(c, &clk_root_list, child_node) {
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if (!first_node)
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seq_printf(s, ",");
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first_node = false;
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clk_dump_subtree(s, c, 0);
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}
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hlist_for_each_entry(c, &clk_orphan_list, child_node) {
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seq_printf(s, ",");
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clk_dump_subtree(s, c, 0);
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}
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clk_prepare_unlock();
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seq_printf(s, "}");
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return 0;
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}
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static int clk_dump_open(struct inode *inode, struct file *file)
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{
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return single_open(file, clk_dump, inode->i_private);
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}
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static const struct file_operations clk_dump_fops = {
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.open = clk_dump_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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/* caller must hold prepare_lock */
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static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
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{
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struct dentry *d;
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int ret = -ENOMEM;
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if (!clk || !pdentry) {
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ret = -EINVAL;
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goto out;
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}
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d = debugfs_create_dir(clk->name, pdentry);
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if (!d)
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goto out;
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clk->dentry = d;
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d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
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(u32 *)&clk->rate);
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if (!d)
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goto err_out;
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d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
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(u32 *)&clk->accuracy);
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if (!d)
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goto err_out;
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d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
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(u32 *)&clk->flags);
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if (!d)
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goto err_out;
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d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
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(u32 *)&clk->prepare_count);
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if (!d)
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goto err_out;
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d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
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(u32 *)&clk->enable_count);
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if (!d)
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goto err_out;
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d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
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(u32 *)&clk->notifier_count);
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if (!d)
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goto err_out;
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ret = 0;
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goto out;
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err_out:
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debugfs_remove_recursive(clk->dentry);
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clk->dentry = NULL;
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out:
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return ret;
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}
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/* caller must hold prepare_lock */
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static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
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{
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struct clk *child;
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int ret = -EINVAL;;
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if (!clk || !pdentry)
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goto out;
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ret = clk_debug_create_one(clk, pdentry);
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if (ret)
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goto out;
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hlist_for_each_entry(child, &clk->children, child_node)
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clk_debug_create_subtree(child, clk->dentry);
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ret = 0;
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out:
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return ret;
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}
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/**
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* clk_debug_register - add a clk node to the debugfs clk tree
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* @clk: the clk being added to the debugfs clk tree
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*
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* Dynamically adds a clk to the debugfs clk tree if debugfs has been
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* initialized. Otherwise it bails out early since the debugfs clk tree
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* will be created lazily by clk_debug_init as part of a late_initcall.
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*
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* Caller must hold prepare_lock. Only clk_init calls this function (so
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* far) so this is taken care.
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*/
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static int clk_debug_register(struct clk *clk)
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{
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struct clk *parent;
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struct dentry *pdentry;
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int ret = 0;
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if (!inited)
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goto out;
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parent = clk->parent;
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/*
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* Check to see if a clk is a root clk. Also check that it is
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* safe to add this clk to debugfs
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*/
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if (!parent)
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if (clk->flags & CLK_IS_ROOT)
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pdentry = rootdir;
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else
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pdentry = orphandir;
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else
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if (parent->dentry)
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pdentry = parent->dentry;
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else
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goto out;
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ret = clk_debug_create_subtree(clk, pdentry);
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out:
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return ret;
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}
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/**
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* clk_debug_unregister - remove a clk node from the debugfs clk tree
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* @clk: the clk being removed from the debugfs clk tree
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*
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* Dynamically removes a clk and all it's children clk nodes from the
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* debugfs clk tree if clk->dentry points to debugfs created by
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* clk_debug_register in __clk_init.
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*
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* Caller must hold prepare_lock.
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*/
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static void clk_debug_unregister(struct clk *clk)
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{
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debugfs_remove_recursive(clk->dentry);
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}
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/**
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* clk_debug_reparent - reparent clk node in the debugfs clk tree
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* @clk: the clk being reparented
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* @new_parent: the new clk parent, may be NULL
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*
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* Rename clk entry in the debugfs clk tree if debugfs has been
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* initialized. Otherwise it bails out early since the debugfs clk tree
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* will be created lazily by clk_debug_init as part of a late_initcall.
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*
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* Caller must hold prepare_lock.
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*/
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static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
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{
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struct dentry *d;
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struct dentry *new_parent_d;
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if (!inited)
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return;
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if (new_parent)
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new_parent_d = new_parent->dentry;
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else
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new_parent_d = orphandir;
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d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
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new_parent_d, clk->name);
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if (d)
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clk->dentry = d;
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else
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pr_debug("%s: failed to rename debugfs entry for %s\n",
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__func__, clk->name);
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}
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/**
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* clk_debug_init - lazily create the debugfs clk tree visualization
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*
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* clks are often initialized very early during boot before memory can
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* be dynamically allocated and well before debugfs is setup.
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* clk_debug_init walks the clk tree hierarchy while holding
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* prepare_lock and creates the topology as part of a late_initcall,
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* thus insuring that clks initialized very early will still be
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* represented in the debugfs clk tree. This function should only be
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* called once at boot-time, and all other clks added dynamically will
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* be done so with clk_debug_register.
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*/
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static int __init clk_debug_init(void)
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{
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struct clk *clk;
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struct dentry *d;
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rootdir = debugfs_create_dir("clk", NULL);
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if (!rootdir)
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return -ENOMEM;
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d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
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&clk_summary_fops);
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if (!d)
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return -ENOMEM;
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d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
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&clk_dump_fops);
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if (!d)
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return -ENOMEM;
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orphandir = debugfs_create_dir("orphans", rootdir);
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if (!orphandir)
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return -ENOMEM;
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clk_prepare_lock();
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hlist_for_each_entry(clk, &clk_root_list, child_node)
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clk_debug_create_subtree(clk, rootdir);
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hlist_for_each_entry(clk, &clk_orphan_list, child_node)
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clk_debug_create_subtree(clk, orphandir);
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inited = 1;
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clk_prepare_unlock();
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return 0;
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}
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late_initcall(clk_debug_init);
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#else
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static inline int clk_debug_register(struct clk *clk) { return 0; }
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static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
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{
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}
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static inline void clk_debug_unregister(struct clk *clk)
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{
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}
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#endif
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|
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/* caller must hold prepare_lock */
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static void clk_unprepare_unused_subtree(struct clk *clk)
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{
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struct clk *child;
|
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if (!clk)
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return;
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hlist_for_each_entry(child, &clk->children, child_node)
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clk_unprepare_unused_subtree(child);
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|
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if (clk->prepare_count)
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return;
|
|
|
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if (clk->flags & CLK_IGNORE_UNUSED)
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return;
|
|
|
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if (__clk_is_prepared(clk)) {
|
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if (clk->ops->unprepare_unused)
|
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clk->ops->unprepare_unused(clk->hw);
|
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else if (clk->ops->unprepare)
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clk->ops->unprepare(clk->hw);
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}
|
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}
|
|
|
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/* caller must hold prepare_lock */
|
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static void clk_disable_unused_subtree(struct clk *clk)
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{
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struct clk *child;
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unsigned long flags;
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|
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if (!clk)
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goto out;
|
|
|
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hlist_for_each_entry(child, &clk->children, child_node)
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clk_disable_unused_subtree(child);
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|
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flags = clk_enable_lock();
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|
|
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if (clk->enable_count)
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goto unlock_out;
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|
|
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if (clk->flags & CLK_IGNORE_UNUSED)
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goto unlock_out;
|
|
|
|
/*
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* some gate clocks have special needs during the disable-unused
|
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* sequence. call .disable_unused if available, otherwise fall
|
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* back to .disable
|
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*/
|
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if (__clk_is_enabled(clk)) {
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if (clk->ops->disable_unused)
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clk->ops->disable_unused(clk->hw);
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else if (clk->ops->disable)
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clk->ops->disable(clk->hw);
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}
|
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|
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unlock_out:
|
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clk_enable_unlock(flags);
|
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|
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out:
|
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return;
|
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}
|
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|
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static bool clk_ignore_unused;
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static int __init clk_ignore_unused_setup(char *__unused)
|
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{
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clk_ignore_unused = true;
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return 1;
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}
|
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__setup("clk_ignore_unused", clk_ignore_unused_setup);
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|
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static int clk_disable_unused(void)
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{
|
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struct clk *clk;
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|
|
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if (clk_ignore_unused) {
|
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pr_warn("clk: Not disabling unused clocks\n");
|
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return 0;
|
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}
|
|
|
|
clk_prepare_lock();
|
|
|
|
hlist_for_each_entry(clk, &clk_root_list, child_node)
|
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clk_disable_unused_subtree(clk);
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|
|
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hlist_for_each_entry(clk, &clk_orphan_list, child_node)
|
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clk_disable_unused_subtree(clk);
|
|
|
|
hlist_for_each_entry(clk, &clk_root_list, child_node)
|
|
clk_unprepare_unused_subtree(clk);
|
|
|
|
hlist_for_each_entry(clk, &clk_orphan_list, child_node)
|
|
clk_unprepare_unused_subtree(clk);
|
|
|
|
clk_prepare_unlock();
|
|
|
|
return 0;
|
|
}
|
|
late_initcall_sync(clk_disable_unused);
|
|
|
|
/*** helper functions ***/
|
|
|
|
const char *__clk_get_name(struct clk *clk)
|
|
{
|
|
return !clk ? NULL : clk->name;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_get_name);
|
|
|
|
struct clk_hw *__clk_get_hw(struct clk *clk)
|
|
{
|
|
return !clk ? NULL : clk->hw;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_get_hw);
|
|
|
|
u8 __clk_get_num_parents(struct clk *clk)
|
|
{
|
|
return !clk ? 0 : clk->num_parents;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_get_num_parents);
|
|
|
|
struct clk *__clk_get_parent(struct clk *clk)
|
|
{
|
|
return !clk ? NULL : clk->parent;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_get_parent);
|
|
|
|
struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
|
|
{
|
|
if (!clk || index >= clk->num_parents)
|
|
return NULL;
|
|
else if (!clk->parents)
|
|
return __clk_lookup(clk->parent_names[index]);
|
|
else if (!clk->parents[index])
|
|
return clk->parents[index] =
|
|
__clk_lookup(clk->parent_names[index]);
|
|
else
|
|
return clk->parents[index];
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
|
|
|
|
unsigned int __clk_get_enable_count(struct clk *clk)
|
|
{
|
|
return !clk ? 0 : clk->enable_count;
|
|
}
|
|
|
|
unsigned int __clk_get_prepare_count(struct clk *clk)
|
|
{
|
|
return !clk ? 0 : clk->prepare_count;
|
|
}
|
|
|
|
unsigned long __clk_get_rate(struct clk *clk)
|
|
{
|
|
unsigned long ret;
|
|
|
|
if (!clk) {
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
|
|
ret = clk->rate;
|
|
|
|
if (clk->flags & CLK_IS_ROOT)
|
|
goto out;
|
|
|
|
if (!clk->parent)
|
|
ret = 0;
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_get_rate);
|
|
|
|
unsigned long __clk_get_accuracy(struct clk *clk)
|
|
{
|
|
if (!clk)
|
|
return 0;
|
|
|
|
return clk->accuracy;
|
|
}
|
|
|
|
unsigned long __clk_get_flags(struct clk *clk)
|
|
{
|
|
return !clk ? 0 : clk->flags;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_get_flags);
|
|
|
|
bool __clk_is_prepared(struct clk *clk)
|
|
{
|
|
int ret;
|
|
|
|
if (!clk)
|
|
return false;
|
|
|
|
/*
|
|
* .is_prepared is optional for clocks that can prepare
|
|
* fall back to software usage counter if it is missing
|
|
*/
|
|
if (!clk->ops->is_prepared) {
|
|
ret = clk->prepare_count ? 1 : 0;
|
|
goto out;
|
|
}
|
|
|
|
ret = clk->ops->is_prepared(clk->hw);
|
|
out:
|
|
return !!ret;
|
|
}
|
|
|
|
bool __clk_is_enabled(struct clk *clk)
|
|
{
|
|
int ret;
|
|
|
|
if (!clk)
|
|
return false;
|
|
|
|
/*
|
|
* .is_enabled is only mandatory for clocks that gate
|
|
* fall back to software usage counter if .is_enabled is missing
|
|
*/
|
|
if (!clk->ops->is_enabled) {
|
|
ret = clk->enable_count ? 1 : 0;
|
|
goto out;
|
|
}
|
|
|
|
ret = clk->ops->is_enabled(clk->hw);
|
|
out:
|
|
return !!ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_is_enabled);
|
|
|
|
static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
|
|
{
|
|
struct clk *child;
|
|
struct clk *ret;
|
|
|
|
if (!strcmp(clk->name, name))
|
|
return clk;
|
|
|
|
hlist_for_each_entry(child, &clk->children, child_node) {
|
|
ret = __clk_lookup_subtree(name, child);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
struct clk *__clk_lookup(const char *name)
|
|
{
|
|
struct clk *root_clk;
|
|
struct clk *ret;
|
|
|
|
if (!name)
|
|
return NULL;
|
|
|
|
/* search the 'proper' clk tree first */
|
|
hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
|
|
ret = __clk_lookup_subtree(name, root_clk);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
/* if not found, then search the orphan tree */
|
|
hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
|
|
ret = __clk_lookup_subtree(name, root_clk);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Helper for finding best parent to provide a given frequency. This can be used
|
|
* directly as a determine_rate callback (e.g. for a mux), or from a more
|
|
* complex clock that may combine a mux with other operations.
|
|
*/
|
|
long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
|
|
unsigned long *best_parent_rate,
|
|
struct clk **best_parent_p)
|
|
{
|
|
struct clk *clk = hw->clk, *parent, *best_parent = NULL;
|
|
int i, num_parents;
|
|
unsigned long parent_rate, best = 0;
|
|
|
|
/* if NO_REPARENT flag set, pass through to current parent */
|
|
if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
|
|
parent = clk->parent;
|
|
if (clk->flags & CLK_SET_RATE_PARENT)
|
|
best = __clk_round_rate(parent, rate);
|
|
else if (parent)
|
|
best = __clk_get_rate(parent);
|
|
else
|
|
best = __clk_get_rate(clk);
|
|
goto out;
|
|
}
|
|
|
|
/* find the parent that can provide the fastest rate <= rate */
|
|
num_parents = clk->num_parents;
|
|
for (i = 0; i < num_parents; i++) {
|
|
parent = clk_get_parent_by_index(clk, i);
|
|
if (!parent)
|
|
continue;
|
|
if (clk->flags & CLK_SET_RATE_PARENT)
|
|
parent_rate = __clk_round_rate(parent, rate);
|
|
else
|
|
parent_rate = __clk_get_rate(parent);
|
|
if (parent_rate <= rate && parent_rate > best) {
|
|
best_parent = parent;
|
|
best = parent_rate;
|
|
}
|
|
}
|
|
|
|
out:
|
|
if (best_parent)
|
|
*best_parent_p = best_parent;
|
|
*best_parent_rate = best;
|
|
|
|
return best;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
|
|
|
|
/*** clk api ***/
|
|
|
|
void __clk_unprepare(struct clk *clk)
|
|
{
|
|
if (!clk)
|
|
return;
|
|
|
|
if (WARN_ON(clk->prepare_count == 0))
|
|
return;
|
|
|
|
if (--clk->prepare_count > 0)
|
|
return;
|
|
|
|
WARN_ON(clk->enable_count > 0);
|
|
|
|
if (clk->ops->unprepare)
|
|
clk->ops->unprepare(clk->hw);
|
|
|
|
__clk_unprepare(clk->parent);
|
|
}
|
|
|
|
/**
|
|
* clk_unprepare - undo preparation of a clock source
|
|
* @clk: the clk being unprepared
|
|
*
|
|
* clk_unprepare may sleep, which differentiates it from clk_disable. In a
|
|
* simple case, clk_unprepare can be used instead of clk_disable to gate a clk
|
|
* if the operation may sleep. One example is a clk which is accessed over
|
|
* I2c. In the complex case a clk gate operation may require a fast and a slow
|
|
* part. It is this reason that clk_unprepare and clk_disable are not mutually
|
|
* exclusive. In fact clk_disable must be called before clk_unprepare.
|
|
*/
|
|
void clk_unprepare(struct clk *clk)
|
|
{
|
|
clk_prepare_lock();
|
|
__clk_unprepare(clk);
|
|
clk_prepare_unlock();
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_unprepare);
|
|
|
|
int __clk_prepare(struct clk *clk)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (!clk)
|
|
return 0;
|
|
|
|
if (clk->prepare_count == 0) {
|
|
ret = __clk_prepare(clk->parent);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (clk->ops->prepare) {
|
|
ret = clk->ops->prepare(clk->hw);
|
|
if (ret) {
|
|
__clk_unprepare(clk->parent);
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
clk->prepare_count++;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* clk_prepare - prepare a clock source
|
|
* @clk: the clk being prepared
|
|
*
|
|
* clk_prepare may sleep, which differentiates it from clk_enable. In a simple
|
|
* case, clk_prepare can be used instead of clk_enable to ungate a clk if the
|
|
* operation may sleep. One example is a clk which is accessed over I2c. In
|
|
* the complex case a clk ungate operation may require a fast and a slow part.
|
|
* It is this reason that clk_prepare and clk_enable are not mutually
|
|
* exclusive. In fact clk_prepare must be called before clk_enable.
|
|
* Returns 0 on success, -EERROR otherwise.
|
|
*/
|
|
int clk_prepare(struct clk *clk)
|
|
{
|
|
int ret;
|
|
|
|
clk_prepare_lock();
|
|
ret = __clk_prepare(clk);
|
|
clk_prepare_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_prepare);
|
|
|
|
static void __clk_disable(struct clk *clk)
|
|
{
|
|
if (!clk)
|
|
return;
|
|
|
|
if (WARN_ON(IS_ERR(clk)))
|
|
return;
|
|
|
|
if (WARN_ON(clk->enable_count == 0))
|
|
return;
|
|
|
|
if (--clk->enable_count > 0)
|
|
return;
|
|
|
|
if (clk->ops->disable)
|
|
clk->ops->disable(clk->hw);
|
|
|
|
__clk_disable(clk->parent);
|
|
}
|
|
|
|
/**
|
|
* clk_disable - gate a clock
|
|
* @clk: the clk being gated
|
|
*
|
|
* clk_disable must not sleep, which differentiates it from clk_unprepare. In
|
|
* a simple case, clk_disable can be used instead of clk_unprepare to gate a
|
|
* clk if the operation is fast and will never sleep. One example is a
|
|
* SoC-internal clk which is controlled via simple register writes. In the
|
|
* complex case a clk gate operation may require a fast and a slow part. It is
|
|
* this reason that clk_unprepare and clk_disable are not mutually exclusive.
|
|
* In fact clk_disable must be called before clk_unprepare.
|
|
*/
|
|
void clk_disable(struct clk *clk)
|
|
{
|
|
unsigned long flags;
|
|
|
|
flags = clk_enable_lock();
|
|
__clk_disable(clk);
|
|
clk_enable_unlock(flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_disable);
|
|
|
|
static int __clk_enable(struct clk *clk)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (!clk)
|
|
return 0;
|
|
|
|
if (WARN_ON(clk->prepare_count == 0))
|
|
return -ESHUTDOWN;
|
|
|
|
if (clk->enable_count == 0) {
|
|
ret = __clk_enable(clk->parent);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (clk->ops->enable) {
|
|
ret = clk->ops->enable(clk->hw);
|
|
if (ret) {
|
|
__clk_disable(clk->parent);
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
clk->enable_count++;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* clk_enable - ungate a clock
|
|
* @clk: the clk being ungated
|
|
*
|
|
* clk_enable must not sleep, which differentiates it from clk_prepare. In a
|
|
* simple case, clk_enable can be used instead of clk_prepare to ungate a clk
|
|
* if the operation will never sleep. One example is a SoC-internal clk which
|
|
* is controlled via simple register writes. In the complex case a clk ungate
|
|
* operation may require a fast and a slow part. It is this reason that
|
|
* clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
|
|
* must be called before clk_enable. Returns 0 on success, -EERROR
|
|
* otherwise.
|
|
*/
|
|
int clk_enable(struct clk *clk)
|
|
{
|
|
unsigned long flags;
|
|
int ret;
|
|
|
|
flags = clk_enable_lock();
|
|
ret = __clk_enable(clk);
|
|
clk_enable_unlock(flags);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_enable);
|
|
|
|
/**
|
|
* __clk_round_rate - round the given rate for a clk
|
|
* @clk: round the rate of this clock
|
|
* @rate: the rate which is to be rounded
|
|
*
|
|
* Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
|
|
*/
|
|
unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
|
|
{
|
|
unsigned long parent_rate = 0;
|
|
struct clk *parent;
|
|
|
|
if (!clk)
|
|
return 0;
|
|
|
|
parent = clk->parent;
|
|
if (parent)
|
|
parent_rate = parent->rate;
|
|
|
|
if (clk->ops->determine_rate)
|
|
return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
|
|
&parent);
|
|
else if (clk->ops->round_rate)
|
|
return clk->ops->round_rate(clk->hw, rate, &parent_rate);
|
|
else if (clk->flags & CLK_SET_RATE_PARENT)
|
|
return __clk_round_rate(clk->parent, rate);
|
|
else
|
|
return clk->rate;
|
|
}
|
|
|
|
/**
|
|
* clk_round_rate - round the given rate for a clk
|
|
* @clk: the clk for which we are rounding a rate
|
|
* @rate: the rate which is to be rounded
|
|
*
|
|
* Takes in a rate as input and rounds it to a rate that the clk can actually
|
|
* use which is then returned. If clk doesn't support round_rate operation
|
|
* then the parent rate is returned.
|
|
*/
|
|
long clk_round_rate(struct clk *clk, unsigned long rate)
|
|
{
|
|
unsigned long ret;
|
|
|
|
clk_prepare_lock();
|
|
ret = __clk_round_rate(clk, rate);
|
|
clk_prepare_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_round_rate);
|
|
|
|
/**
|
|
* __clk_notify - call clk notifier chain
|
|
* @clk: struct clk * that is changing rate
|
|
* @msg: clk notifier type (see include/linux/clk.h)
|
|
* @old_rate: old clk rate
|
|
* @new_rate: new clk rate
|
|
*
|
|
* Triggers a notifier call chain on the clk rate-change notification
|
|
* for 'clk'. Passes a pointer to the struct clk and the previous
|
|
* and current rates to the notifier callback. Intended to be called by
|
|
* internal clock code only. Returns NOTIFY_DONE from the last driver
|
|
* called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
|
|
* a driver returns that.
|
|
*/
|
|
static int __clk_notify(struct clk *clk, unsigned long msg,
|
|
unsigned long old_rate, unsigned long new_rate)
|
|
{
|
|
struct clk_notifier *cn;
|
|
struct clk_notifier_data cnd;
|
|
int ret = NOTIFY_DONE;
|
|
|
|
cnd.clk = clk;
|
|
cnd.old_rate = old_rate;
|
|
cnd.new_rate = new_rate;
|
|
|
|
list_for_each_entry(cn, &clk_notifier_list, node) {
|
|
if (cn->clk == clk) {
|
|
ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
|
|
&cnd);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* __clk_recalc_accuracies
|
|
* @clk: first clk in the subtree
|
|
*
|
|
* Walks the subtree of clks starting with clk and recalculates accuracies as
|
|
* it goes. Note that if a clk does not implement the .recalc_accuracy
|
|
* callback then it is assumed that the clock will take on the accuracy of it's
|
|
* parent.
|
|
*
|
|
* Caller must hold prepare_lock.
|
|
*/
|
|
static void __clk_recalc_accuracies(struct clk *clk)
|
|
{
|
|
unsigned long parent_accuracy = 0;
|
|
struct clk *child;
|
|
|
|
if (clk->parent)
|
|
parent_accuracy = clk->parent->accuracy;
|
|
|
|
if (clk->ops->recalc_accuracy)
|
|
clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
|
|
parent_accuracy);
|
|
else
|
|
clk->accuracy = parent_accuracy;
|
|
|
|
hlist_for_each_entry(child, &clk->children, child_node)
|
|
__clk_recalc_accuracies(child);
|
|
}
|
|
|
|
/**
|
|
* clk_get_accuracy - return the accuracy of clk
|
|
* @clk: the clk whose accuracy is being returned
|
|
*
|
|
* Simply returns the cached accuracy of the clk, unless
|
|
* CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
|
|
* issued.
|
|
* If clk is NULL then returns 0.
|
|
*/
|
|
long clk_get_accuracy(struct clk *clk)
|
|
{
|
|
unsigned long accuracy;
|
|
|
|
clk_prepare_lock();
|
|
if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
|
|
__clk_recalc_accuracies(clk);
|
|
|
|
accuracy = __clk_get_accuracy(clk);
|
|
clk_prepare_unlock();
|
|
|
|
return accuracy;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_get_accuracy);
|
|
|
|
/**
|
|
* __clk_recalc_rates
|
|
* @clk: first clk in the subtree
|
|
* @msg: notification type (see include/linux/clk.h)
|
|
*
|
|
* Walks the subtree of clks starting with clk and recalculates rates as it
|
|
* goes. Note that if a clk does not implement the .recalc_rate callback then
|
|
* it is assumed that the clock will take on the rate of its parent.
|
|
*
|
|
* clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
|
|
* if necessary.
|
|
*
|
|
* Caller must hold prepare_lock.
|
|
*/
|
|
static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
|
|
{
|
|
unsigned long old_rate;
|
|
unsigned long parent_rate = 0;
|
|
struct clk *child;
|
|
|
|
old_rate = clk->rate;
|
|
|
|
if (clk->parent)
|
|
parent_rate = clk->parent->rate;
|
|
|
|
if (clk->ops->recalc_rate)
|
|
clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
|
|
else
|
|
clk->rate = parent_rate;
|
|
|
|
/*
|
|
* ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
|
|
* & ABORT_RATE_CHANGE notifiers
|
|
*/
|
|
if (clk->notifier_count && msg)
|
|
__clk_notify(clk, msg, old_rate, clk->rate);
|
|
|
|
hlist_for_each_entry(child, &clk->children, child_node)
|
|
__clk_recalc_rates(child, msg);
|
|
}
|
|
|
|
/**
|
|
* clk_get_rate - return the rate of clk
|
|
* @clk: the clk whose rate is being returned
|
|
*
|
|
* Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
|
|
* is set, which means a recalc_rate will be issued.
|
|
* If clk is NULL then returns 0.
|
|
*/
|
|
unsigned long clk_get_rate(struct clk *clk)
|
|
{
|
|
unsigned long rate;
|
|
|
|
clk_prepare_lock();
|
|
|
|
if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
|
|
__clk_recalc_rates(clk, 0);
|
|
|
|
rate = __clk_get_rate(clk);
|
|
clk_prepare_unlock();
|
|
|
|
return rate;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_get_rate);
|
|
|
|
static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
|
|
{
|
|
int i;
|
|
|
|
if (!clk->parents) {
|
|
clk->parents = kcalloc(clk->num_parents,
|
|
sizeof(struct clk *), GFP_KERNEL);
|
|
if (!clk->parents)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* find index of new parent clock using cached parent ptrs,
|
|
* or if not yet cached, use string name comparison and cache
|
|
* them now to avoid future calls to __clk_lookup.
|
|
*/
|
|
for (i = 0; i < clk->num_parents; i++) {
|
|
if (clk->parents[i] == parent)
|
|
return i;
|
|
|
|
if (clk->parents[i])
|
|
continue;
|
|
|
|
if (!strcmp(clk->parent_names[i], parent->name)) {
|
|
clk->parents[i] = __clk_lookup(parent->name);
|
|
return i;
|
|
}
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static void clk_reparent(struct clk *clk, struct clk *new_parent)
|
|
{
|
|
hlist_del(&clk->child_node);
|
|
|
|
if (new_parent) {
|
|
/* avoid duplicate POST_RATE_CHANGE notifications */
|
|
if (new_parent->new_child == clk)
|
|
new_parent->new_child = NULL;
|
|
|
|
hlist_add_head(&clk->child_node, &new_parent->children);
|
|
} else {
|
|
hlist_add_head(&clk->child_node, &clk_orphan_list);
|
|
}
|
|
|
|
clk->parent = new_parent;
|
|
}
|
|
|
|
static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
|
|
{
|
|
unsigned long flags;
|
|
struct clk *old_parent = clk->parent;
|
|
|
|
/*
|
|
* Migrate prepare state between parents and prevent race with
|
|
* clk_enable().
|
|
*
|
|
* If the clock is not prepared, then a race with
|
|
* clk_enable/disable() is impossible since we already have the
|
|
* prepare lock (future calls to clk_enable() need to be preceded by
|
|
* a clk_prepare()).
|
|
*
|
|
* If the clock is prepared, migrate the prepared state to the new
|
|
* parent and also protect against a race with clk_enable() by
|
|
* forcing the clock and the new parent on. This ensures that all
|
|
* future calls to clk_enable() are practically NOPs with respect to
|
|
* hardware and software states.
|
|
*
|
|
* See also: Comment for clk_set_parent() below.
|
|
*/
|
|
if (clk->prepare_count) {
|
|
__clk_prepare(parent);
|
|
clk_enable(parent);
|
|
clk_enable(clk);
|
|
}
|
|
|
|
/* update the clk tree topology */
|
|
flags = clk_enable_lock();
|
|
clk_reparent(clk, parent);
|
|
clk_enable_unlock(flags);
|
|
|
|
return old_parent;
|
|
}
|
|
|
|
static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
|
|
struct clk *old_parent)
|
|
{
|
|
/*
|
|
* Finish the migration of prepare state and undo the changes done
|
|
* for preventing a race with clk_enable().
|
|
*/
|
|
if (clk->prepare_count) {
|
|
clk_disable(clk);
|
|
clk_disable(old_parent);
|
|
__clk_unprepare(old_parent);
|
|
}
|
|
|
|
/* update debugfs with new clk tree topology */
|
|
clk_debug_reparent(clk, parent);
|
|
}
|
|
|
|
static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
|
|
{
|
|
unsigned long flags;
|
|
int ret = 0;
|
|
struct clk *old_parent;
|
|
|
|
old_parent = __clk_set_parent_before(clk, parent);
|
|
|
|
/* change clock input source */
|
|
if (parent && clk->ops->set_parent)
|
|
ret = clk->ops->set_parent(clk->hw, p_index);
|
|
|
|
if (ret) {
|
|
flags = clk_enable_lock();
|
|
clk_reparent(clk, old_parent);
|
|
clk_enable_unlock(flags);
|
|
|
|
if (clk->prepare_count) {
|
|
clk_disable(clk);
|
|
clk_disable(parent);
|
|
__clk_unprepare(parent);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
__clk_set_parent_after(clk, parent, old_parent);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* __clk_speculate_rates
|
|
* @clk: first clk in the subtree
|
|
* @parent_rate: the "future" rate of clk's parent
|
|
*
|
|
* Walks the subtree of clks starting with clk, speculating rates as it
|
|
* goes and firing off PRE_RATE_CHANGE notifications as necessary.
|
|
*
|
|
* Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
|
|
* pre-rate change notifications and returns early if no clks in the
|
|
* subtree have subscribed to the notifications. Note that if a clk does not
|
|
* implement the .recalc_rate callback then it is assumed that the clock will
|
|
* take on the rate of its parent.
|
|
*
|
|
* Caller must hold prepare_lock.
|
|
*/
|
|
static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
|
|
{
|
|
struct clk *child;
|
|
unsigned long new_rate;
|
|
int ret = NOTIFY_DONE;
|
|
|
|
if (clk->ops->recalc_rate)
|
|
new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
|
|
else
|
|
new_rate = parent_rate;
|
|
|
|
/* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
|
|
if (clk->notifier_count)
|
|
ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
|
|
|
|
if (ret & NOTIFY_STOP_MASK)
|
|
goto out;
|
|
|
|
hlist_for_each_entry(child, &clk->children, child_node) {
|
|
ret = __clk_speculate_rates(child, new_rate);
|
|
if (ret & NOTIFY_STOP_MASK)
|
|
break;
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
|
|
struct clk *new_parent, u8 p_index)
|
|
{
|
|
struct clk *child;
|
|
|
|
clk->new_rate = new_rate;
|
|
clk->new_parent = new_parent;
|
|
clk->new_parent_index = p_index;
|
|
/* include clk in new parent's PRE_RATE_CHANGE notifications */
|
|
clk->new_child = NULL;
|
|
if (new_parent && new_parent != clk->parent)
|
|
new_parent->new_child = clk;
|
|
|
|
hlist_for_each_entry(child, &clk->children, child_node) {
|
|
if (child->ops->recalc_rate)
|
|
child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
|
|
else
|
|
child->new_rate = new_rate;
|
|
clk_calc_subtree(child, child->new_rate, NULL, 0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* calculate the new rates returning the topmost clock that has to be
|
|
* changed.
|
|
*/
|
|
static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
|
|
{
|
|
struct clk *top = clk;
|
|
struct clk *old_parent, *parent;
|
|
unsigned long best_parent_rate = 0;
|
|
unsigned long new_rate;
|
|
int p_index = 0;
|
|
|
|
/* sanity */
|
|
if (IS_ERR_OR_NULL(clk))
|
|
return NULL;
|
|
|
|
/* save parent rate, if it exists */
|
|
parent = old_parent = clk->parent;
|
|
if (parent)
|
|
best_parent_rate = parent->rate;
|
|
|
|
/* find the closest rate and parent clk/rate */
|
|
if (clk->ops->determine_rate) {
|
|
new_rate = clk->ops->determine_rate(clk->hw, rate,
|
|
&best_parent_rate,
|
|
&parent);
|
|
} else if (clk->ops->round_rate) {
|
|
new_rate = clk->ops->round_rate(clk->hw, rate,
|
|
&best_parent_rate);
|
|
} else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
|
|
/* pass-through clock without adjustable parent */
|
|
clk->new_rate = clk->rate;
|
|
return NULL;
|
|
} else {
|
|
/* pass-through clock with adjustable parent */
|
|
top = clk_calc_new_rates(parent, rate);
|
|
new_rate = parent->new_rate;
|
|
goto out;
|
|
}
|
|
|
|
/* some clocks must be gated to change parent */
|
|
if (parent != old_parent &&
|
|
(clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
|
|
pr_debug("%s: %s not gated but wants to reparent\n",
|
|
__func__, clk->name);
|
|
return NULL;
|
|
}
|
|
|
|
/* try finding the new parent index */
|
|
if (parent) {
|
|
p_index = clk_fetch_parent_index(clk, parent);
|
|
if (p_index < 0) {
|
|
pr_debug("%s: clk %s can not be parent of clk %s\n",
|
|
__func__, parent->name, clk->name);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
|
|
best_parent_rate != parent->rate)
|
|
top = clk_calc_new_rates(parent, best_parent_rate);
|
|
|
|
out:
|
|
clk_calc_subtree(clk, new_rate, parent, p_index);
|
|
|
|
return top;
|
|
}
|
|
|
|
/*
|
|
* Notify about rate changes in a subtree. Always walk down the whole tree
|
|
* so that in case of an error we can walk down the whole tree again and
|
|
* abort the change.
|
|
*/
|
|
static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
|
|
{
|
|
struct clk *child, *tmp_clk, *fail_clk = NULL;
|
|
int ret = NOTIFY_DONE;
|
|
|
|
if (clk->rate == clk->new_rate)
|
|
return NULL;
|
|
|
|
if (clk->notifier_count) {
|
|
ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
|
|
if (ret & NOTIFY_STOP_MASK)
|
|
fail_clk = clk;
|
|
}
|
|
|
|
hlist_for_each_entry(child, &clk->children, child_node) {
|
|
/* Skip children who will be reparented to another clock */
|
|
if (child->new_parent && child->new_parent != clk)
|
|
continue;
|
|
tmp_clk = clk_propagate_rate_change(child, event);
|
|
if (tmp_clk)
|
|
fail_clk = tmp_clk;
|
|
}
|
|
|
|
/* handle the new child who might not be in clk->children yet */
|
|
if (clk->new_child) {
|
|
tmp_clk = clk_propagate_rate_change(clk->new_child, event);
|
|
if (tmp_clk)
|
|
fail_clk = tmp_clk;
|
|
}
|
|
|
|
return fail_clk;
|
|
}
|
|
|
|
/*
|
|
* walk down a subtree and set the new rates notifying the rate
|
|
* change on the way
|
|
*/
|
|
static void clk_change_rate(struct clk *clk)
|
|
{
|
|
struct clk *child;
|
|
unsigned long old_rate;
|
|
unsigned long best_parent_rate = 0;
|
|
bool skip_set_rate = false;
|
|
struct clk *old_parent;
|
|
|
|
old_rate = clk->rate;
|
|
|
|
if (clk->new_parent)
|
|
best_parent_rate = clk->new_parent->rate;
|
|
else if (clk->parent)
|
|
best_parent_rate = clk->parent->rate;
|
|
|
|
if (clk->new_parent && clk->new_parent != clk->parent) {
|
|
old_parent = __clk_set_parent_before(clk, clk->new_parent);
|
|
|
|
if (clk->ops->set_rate_and_parent) {
|
|
skip_set_rate = true;
|
|
clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
|
|
best_parent_rate,
|
|
clk->new_parent_index);
|
|
} else if (clk->ops->set_parent) {
|
|
clk->ops->set_parent(clk->hw, clk->new_parent_index);
|
|
}
|
|
|
|
__clk_set_parent_after(clk, clk->new_parent, old_parent);
|
|
}
|
|
|
|
if (!skip_set_rate && clk->ops->set_rate)
|
|
clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
|
|
|
|
if (clk->ops->recalc_rate)
|
|
clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
|
|
else
|
|
clk->rate = best_parent_rate;
|
|
|
|
if (clk->notifier_count && old_rate != clk->rate)
|
|
__clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
|
|
|
|
hlist_for_each_entry(child, &clk->children, child_node) {
|
|
/* Skip children who will be reparented to another clock */
|
|
if (child->new_parent && child->new_parent != clk)
|
|
continue;
|
|
clk_change_rate(child);
|
|
}
|
|
|
|
/* handle the new child who might not be in clk->children yet */
|
|
if (clk->new_child)
|
|
clk_change_rate(clk->new_child);
|
|
}
|
|
|
|
/**
|
|
* clk_set_rate - specify a new rate for clk
|
|
* @clk: the clk whose rate is being changed
|
|
* @rate: the new rate for clk
|
|
*
|
|
* In the simplest case clk_set_rate will only adjust the rate of clk.
|
|
*
|
|
* Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
|
|
* propagate up to clk's parent; whether or not this happens depends on the
|
|
* outcome of clk's .round_rate implementation. If *parent_rate is unchanged
|
|
* after calling .round_rate then upstream parent propagation is ignored. If
|
|
* *parent_rate comes back with a new rate for clk's parent then we propagate
|
|
* up to clk's parent and set its rate. Upward propagation will continue
|
|
* until either a clk does not support the CLK_SET_RATE_PARENT flag or
|
|
* .round_rate stops requesting changes to clk's parent_rate.
|
|
*
|
|
* Rate changes are accomplished via tree traversal that also recalculates the
|
|
* rates for the clocks and fires off POST_RATE_CHANGE notifiers.
|
|
*
|
|
* Returns 0 on success, -EERROR otherwise.
|
|
*/
|
|
int clk_set_rate(struct clk *clk, unsigned long rate)
|
|
{
|
|
struct clk *top, *fail_clk;
|
|
int ret = 0;
|
|
|
|
if (!clk)
|
|
return 0;
|
|
|
|
/* prevent racing with updates to the clock topology */
|
|
clk_prepare_lock();
|
|
|
|
/* bail early if nothing to do */
|
|
if (rate == clk_get_rate(clk))
|
|
goto out;
|
|
|
|
if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
/* calculate new rates and get the topmost changed clock */
|
|
top = clk_calc_new_rates(clk, rate);
|
|
if (!top) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* notify that we are about to change rates */
|
|
fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
|
|
if (fail_clk) {
|
|
pr_warn("%s: failed to set %s rate\n", __func__,
|
|
fail_clk->name);
|
|
clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
/* change the rates */
|
|
clk_change_rate(top);
|
|
|
|
out:
|
|
clk_prepare_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_set_rate);
|
|
|
|
/**
|
|
* clk_get_parent - return the parent of a clk
|
|
* @clk: the clk whose parent gets returned
|
|
*
|
|
* Simply returns clk->parent. Returns NULL if clk is NULL.
|
|
*/
|
|
struct clk *clk_get_parent(struct clk *clk)
|
|
{
|
|
struct clk *parent;
|
|
|
|
clk_prepare_lock();
|
|
parent = __clk_get_parent(clk);
|
|
clk_prepare_unlock();
|
|
|
|
return parent;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_get_parent);
|
|
|
|
/*
|
|
* .get_parent is mandatory for clocks with multiple possible parents. It is
|
|
* optional for single-parent clocks. Always call .get_parent if it is
|
|
* available and WARN if it is missing for multi-parent clocks.
|
|
*
|
|
* For single-parent clocks without .get_parent, first check to see if the
|
|
* .parents array exists, and if so use it to avoid an expensive tree
|
|
* traversal. If .parents does not exist then walk the tree with __clk_lookup.
|
|
*/
|
|
static struct clk *__clk_init_parent(struct clk *clk)
|
|
{
|
|
struct clk *ret = NULL;
|
|
u8 index;
|
|
|
|
/* handle the trivial cases */
|
|
|
|
if (!clk->num_parents)
|
|
goto out;
|
|
|
|
if (clk->num_parents == 1) {
|
|
if (IS_ERR_OR_NULL(clk->parent))
|
|
ret = clk->parent = __clk_lookup(clk->parent_names[0]);
|
|
ret = clk->parent;
|
|
goto out;
|
|
}
|
|
|
|
if (!clk->ops->get_parent) {
|
|
WARN(!clk->ops->get_parent,
|
|
"%s: multi-parent clocks must implement .get_parent\n",
|
|
__func__);
|
|
goto out;
|
|
};
|
|
|
|
/*
|
|
* Do our best to cache parent clocks in clk->parents. This prevents
|
|
* unnecessary and expensive calls to __clk_lookup. We don't set
|
|
* clk->parent here; that is done by the calling function
|
|
*/
|
|
|
|
index = clk->ops->get_parent(clk->hw);
|
|
|
|
if (!clk->parents)
|
|
clk->parents =
|
|
kcalloc(clk->num_parents, sizeof(struct clk *),
|
|
GFP_KERNEL);
|
|
|
|
ret = clk_get_parent_by_index(clk, index);
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
void __clk_reparent(struct clk *clk, struct clk *new_parent)
|
|
{
|
|
clk_reparent(clk, new_parent);
|
|
clk_debug_reparent(clk, new_parent);
|
|
__clk_recalc_accuracies(clk);
|
|
__clk_recalc_rates(clk, POST_RATE_CHANGE);
|
|
}
|
|
|
|
/**
|
|
* clk_set_parent - switch the parent of a mux clk
|
|
* @clk: the mux clk whose input we are switching
|
|
* @parent: the new input to clk
|
|
*
|
|
* Re-parent clk to use parent as its new input source. If clk is in
|
|
* prepared state, the clk will get enabled for the duration of this call. If
|
|
* that's not acceptable for a specific clk (Eg: the consumer can't handle
|
|
* that, the reparenting is glitchy in hardware, etc), use the
|
|
* CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
|
|
*
|
|
* After successfully changing clk's parent clk_set_parent will update the
|
|
* clk topology, sysfs topology and propagate rate recalculation via
|
|
* __clk_recalc_rates.
|
|
*
|
|
* Returns 0 on success, -EERROR otherwise.
|
|
*/
|
|
int clk_set_parent(struct clk *clk, struct clk *parent)
|
|
{
|
|
int ret = 0;
|
|
int p_index = 0;
|
|
unsigned long p_rate = 0;
|
|
|
|
if (!clk)
|
|
return 0;
|
|
|
|
if (!clk->ops)
|
|
return -EINVAL;
|
|
|
|
/* verify ops for for multi-parent clks */
|
|
if ((clk->num_parents > 1) && (!clk->ops->set_parent))
|
|
return -ENOSYS;
|
|
|
|
/* prevent racing with updates to the clock topology */
|
|
clk_prepare_lock();
|
|
|
|
if (clk->parent == parent)
|
|
goto out;
|
|
|
|
/* check that we are allowed to re-parent if the clock is in use */
|
|
if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
/* try finding the new parent index */
|
|
if (parent) {
|
|
p_index = clk_fetch_parent_index(clk, parent);
|
|
p_rate = parent->rate;
|
|
if (p_index < 0) {
|
|
pr_debug("%s: clk %s can not be parent of clk %s\n",
|
|
__func__, parent->name, clk->name);
|
|
ret = p_index;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/* propagate PRE_RATE_CHANGE notifications */
|
|
ret = __clk_speculate_rates(clk, p_rate);
|
|
|
|
/* abort if a driver objects */
|
|
if (ret & NOTIFY_STOP_MASK)
|
|
goto out;
|
|
|
|
/* do the re-parent */
|
|
ret = __clk_set_parent(clk, parent, p_index);
|
|
|
|
/* propagate rate an accuracy recalculation accordingly */
|
|
if (ret) {
|
|
__clk_recalc_rates(clk, ABORT_RATE_CHANGE);
|
|
} else {
|
|
__clk_recalc_rates(clk, POST_RATE_CHANGE);
|
|
__clk_recalc_accuracies(clk);
|
|
}
|
|
|
|
out:
|
|
clk_prepare_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_set_parent);
|
|
|
|
/**
|
|
* __clk_init - initialize the data structures in a struct clk
|
|
* @dev: device initializing this clk, placeholder for now
|
|
* @clk: clk being initialized
|
|
*
|
|
* Initializes the lists in struct clk, queries the hardware for the
|
|
* parent and rate and sets them both.
|
|
*/
|
|
int __clk_init(struct device *dev, struct clk *clk)
|
|
{
|
|
int i, ret = 0;
|
|
struct clk *orphan;
|
|
struct hlist_node *tmp2;
|
|
|
|
if (!clk)
|
|
return -EINVAL;
|
|
|
|
clk_prepare_lock();
|
|
|
|
/* check to see if a clock with this name is already registered */
|
|
if (__clk_lookup(clk->name)) {
|
|
pr_debug("%s: clk %s already initialized\n",
|
|
__func__, clk->name);
|
|
ret = -EEXIST;
|
|
goto out;
|
|
}
|
|
|
|
/* check that clk_ops are sane. See Documentation/clk.txt */
|
|
if (clk->ops->set_rate &&
|
|
!((clk->ops->round_rate || clk->ops->determine_rate) &&
|
|
clk->ops->recalc_rate)) {
|
|
pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
|
|
__func__, clk->name);
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (clk->ops->set_parent && !clk->ops->get_parent) {
|
|
pr_warning("%s: %s must implement .get_parent & .set_parent\n",
|
|
__func__, clk->name);
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (clk->ops->set_rate_and_parent &&
|
|
!(clk->ops->set_parent && clk->ops->set_rate)) {
|
|
pr_warn("%s: %s must implement .set_parent & .set_rate\n",
|
|
__func__, clk->name);
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* throw a WARN if any entries in parent_names are NULL */
|
|
for (i = 0; i < clk->num_parents; i++)
|
|
WARN(!clk->parent_names[i],
|
|
"%s: invalid NULL in %s's .parent_names\n",
|
|
__func__, clk->name);
|
|
|
|
/*
|
|
* Allocate an array of struct clk *'s to avoid unnecessary string
|
|
* look-ups of clk's possible parents. This can fail for clocks passed
|
|
* in to clk_init during early boot; thus any access to clk->parents[]
|
|
* must always check for a NULL pointer and try to populate it if
|
|
* necessary.
|
|
*
|
|
* If clk->parents is not NULL we skip this entire block. This allows
|
|
* for clock drivers to statically initialize clk->parents.
|
|
*/
|
|
if (clk->num_parents > 1 && !clk->parents) {
|
|
clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
|
|
GFP_KERNEL);
|
|
/*
|
|
* __clk_lookup returns NULL for parents that have not been
|
|
* clk_init'd; thus any access to clk->parents[] must check
|
|
* for a NULL pointer. We can always perform lazy lookups for
|
|
* missing parents later on.
|
|
*/
|
|
if (clk->parents)
|
|
for (i = 0; i < clk->num_parents; i++)
|
|
clk->parents[i] =
|
|
__clk_lookup(clk->parent_names[i]);
|
|
}
|
|
|
|
clk->parent = __clk_init_parent(clk);
|
|
|
|
/*
|
|
* Populate clk->parent if parent has already been __clk_init'd. If
|
|
* parent has not yet been __clk_init'd then place clk in the orphan
|
|
* list. If clk has set the CLK_IS_ROOT flag then place it in the root
|
|
* clk list.
|
|
*
|
|
* Every time a new clk is clk_init'd then we walk the list of orphan
|
|
* clocks and re-parent any that are children of the clock currently
|
|
* being clk_init'd.
|
|
*/
|
|
if (clk->parent)
|
|
hlist_add_head(&clk->child_node,
|
|
&clk->parent->children);
|
|
else if (clk->flags & CLK_IS_ROOT)
|
|
hlist_add_head(&clk->child_node, &clk_root_list);
|
|
else
|
|
hlist_add_head(&clk->child_node, &clk_orphan_list);
|
|
|
|
/*
|
|
* Set clk's accuracy. The preferred method is to use
|
|
* .recalc_accuracy. For simple clocks and lazy developers the default
|
|
* fallback is to use the parent's accuracy. If a clock doesn't have a
|
|
* parent (or is orphaned) then accuracy is set to zero (perfect
|
|
* clock).
|
|
*/
|
|
if (clk->ops->recalc_accuracy)
|
|
clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
|
|
__clk_get_accuracy(clk->parent));
|
|
else if (clk->parent)
|
|
clk->accuracy = clk->parent->accuracy;
|
|
else
|
|
clk->accuracy = 0;
|
|
|
|
/*
|
|
* Set clk's rate. The preferred method is to use .recalc_rate. For
|
|
* simple clocks and lazy developers the default fallback is to use the
|
|
* parent's rate. If a clock doesn't have a parent (or is orphaned)
|
|
* then rate is set to zero.
|
|
*/
|
|
if (clk->ops->recalc_rate)
|
|
clk->rate = clk->ops->recalc_rate(clk->hw,
|
|
__clk_get_rate(clk->parent));
|
|
else if (clk->parent)
|
|
clk->rate = clk->parent->rate;
|
|
else
|
|
clk->rate = 0;
|
|
|
|
clk_debug_register(clk);
|
|
/*
|
|
* walk the list of orphan clocks and reparent any that are children of
|
|
* this clock
|
|
*/
|
|
hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
|
|
if (orphan->num_parents && orphan->ops->get_parent) {
|
|
i = orphan->ops->get_parent(orphan->hw);
|
|
if (!strcmp(clk->name, orphan->parent_names[i]))
|
|
__clk_reparent(orphan, clk);
|
|
continue;
|
|
}
|
|
|
|
for (i = 0; i < orphan->num_parents; i++)
|
|
if (!strcmp(clk->name, orphan->parent_names[i])) {
|
|
__clk_reparent(orphan, clk);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* optional platform-specific magic
|
|
*
|
|
* The .init callback is not used by any of the basic clock types, but
|
|
* exists for weird hardware that must perform initialization magic.
|
|
* Please consider other ways of solving initialization problems before
|
|
* using this callback, as its use is discouraged.
|
|
*/
|
|
if (clk->ops->init)
|
|
clk->ops->init(clk->hw);
|
|
|
|
kref_init(&clk->ref);
|
|
out:
|
|
clk_prepare_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* __clk_register - register a clock and return a cookie.
|
|
*
|
|
* Same as clk_register, except that the .clk field inside hw shall point to a
|
|
* preallocated (generally statically allocated) struct clk. None of the fields
|
|
* of the struct clk need to be initialized.
|
|
*
|
|
* The data pointed to by .init and .clk field shall NOT be marked as init
|
|
* data.
|
|
*
|
|
* __clk_register is only exposed via clk-private.h and is intended for use with
|
|
* very large numbers of clocks that need to be statically initialized. It is
|
|
* a layering violation to include clk-private.h from any code which implements
|
|
* a clock's .ops; as such any statically initialized clock data MUST be in a
|
|
* separate C file from the logic that implements its operations. Returns 0
|
|
* on success, otherwise an error code.
|
|
*/
|
|
struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
|
|
{
|
|
int ret;
|
|
struct clk *clk;
|
|
|
|
clk = hw->clk;
|
|
clk->name = hw->init->name;
|
|
clk->ops = hw->init->ops;
|
|
clk->hw = hw;
|
|
clk->flags = hw->init->flags;
|
|
clk->parent_names = hw->init->parent_names;
|
|
clk->num_parents = hw->init->num_parents;
|
|
if (dev && dev->driver)
|
|
clk->owner = dev->driver->owner;
|
|
else
|
|
clk->owner = NULL;
|
|
|
|
ret = __clk_init(dev, clk);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
return clk;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_register);
|
|
|
|
static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
|
|
{
|
|
int i, ret;
|
|
|
|
clk->name = kstrdup(hw->init->name, GFP_KERNEL);
|
|
if (!clk->name) {
|
|
pr_err("%s: could not allocate clk->name\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_name;
|
|
}
|
|
clk->ops = hw->init->ops;
|
|
if (dev && dev->driver)
|
|
clk->owner = dev->driver->owner;
|
|
clk->hw = hw;
|
|
clk->flags = hw->init->flags;
|
|
clk->num_parents = hw->init->num_parents;
|
|
hw->clk = clk;
|
|
|
|
/* allocate local copy in case parent_names is __initdata */
|
|
clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
|
|
GFP_KERNEL);
|
|
|
|
if (!clk->parent_names) {
|
|
pr_err("%s: could not allocate clk->parent_names\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_parent_names;
|
|
}
|
|
|
|
|
|
/* copy each string name in case parent_names is __initdata */
|
|
for (i = 0; i < clk->num_parents; i++) {
|
|
clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
|
|
GFP_KERNEL);
|
|
if (!clk->parent_names[i]) {
|
|
pr_err("%s: could not copy parent_names\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_parent_names_copy;
|
|
}
|
|
}
|
|
|
|
ret = __clk_init(dev, clk);
|
|
if (!ret)
|
|
return 0;
|
|
|
|
fail_parent_names_copy:
|
|
while (--i >= 0)
|
|
kfree(clk->parent_names[i]);
|
|
kfree(clk->parent_names);
|
|
fail_parent_names:
|
|
kfree(clk->name);
|
|
fail_name:
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* clk_register - allocate a new clock, register it and return an opaque cookie
|
|
* @dev: device that is registering this clock
|
|
* @hw: link to hardware-specific clock data
|
|
*
|
|
* clk_register is the primary interface for populating the clock tree with new
|
|
* clock nodes. It returns a pointer to the newly allocated struct clk which
|
|
* cannot be dereferenced by driver code but may be used in conjuction with the
|
|
* rest of the clock API. In the event of an error clk_register will return an
|
|
* error code; drivers must test for an error code after calling clk_register.
|
|
*/
|
|
struct clk *clk_register(struct device *dev, struct clk_hw *hw)
|
|
{
|
|
int ret;
|
|
struct clk *clk;
|
|
|
|
clk = kzalloc(sizeof(*clk), GFP_KERNEL);
|
|
if (!clk) {
|
|
pr_err("%s: could not allocate clk\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_out;
|
|
}
|
|
|
|
ret = _clk_register(dev, hw, clk);
|
|
if (!ret)
|
|
return clk;
|
|
|
|
kfree(clk);
|
|
fail_out:
|
|
return ERR_PTR(ret);
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_register);
|
|
|
|
/*
|
|
* Free memory allocated for a clock.
|
|
* Caller must hold prepare_lock.
|
|
*/
|
|
static void __clk_release(struct kref *ref)
|
|
{
|
|
struct clk *clk = container_of(ref, struct clk, ref);
|
|
int i = clk->num_parents;
|
|
|
|
kfree(clk->parents);
|
|
while (--i >= 0)
|
|
kfree(clk->parent_names[i]);
|
|
|
|
kfree(clk->parent_names);
|
|
kfree(clk->name);
|
|
kfree(clk);
|
|
}
|
|
|
|
/*
|
|
* Empty clk_ops for unregistered clocks. These are used temporarily
|
|
* after clk_unregister() was called on a clock and until last clock
|
|
* consumer calls clk_put() and the struct clk object is freed.
|
|
*/
|
|
static int clk_nodrv_prepare_enable(struct clk_hw *hw)
|
|
{
|
|
return -ENXIO;
|
|
}
|
|
|
|
static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
|
|
{
|
|
WARN_ON_ONCE(1);
|
|
}
|
|
|
|
static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
|
|
unsigned long parent_rate)
|
|
{
|
|
return -ENXIO;
|
|
}
|
|
|
|
static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
|
|
{
|
|
return -ENXIO;
|
|
}
|
|
|
|
static const struct clk_ops clk_nodrv_ops = {
|
|
.enable = clk_nodrv_prepare_enable,
|
|
.disable = clk_nodrv_disable_unprepare,
|
|
.prepare = clk_nodrv_prepare_enable,
|
|
.unprepare = clk_nodrv_disable_unprepare,
|
|
.set_rate = clk_nodrv_set_rate,
|
|
.set_parent = clk_nodrv_set_parent,
|
|
};
|
|
|
|
/**
|
|
* clk_unregister - unregister a currently registered clock
|
|
* @clk: clock to unregister
|
|
*/
|
|
void clk_unregister(struct clk *clk)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
|
|
return;
|
|
|
|
clk_prepare_lock();
|
|
|
|
if (clk->ops == &clk_nodrv_ops) {
|
|
pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
|
|
goto out;
|
|
}
|
|
/*
|
|
* Assign empty clock ops for consumers that might still hold
|
|
* a reference to this clock.
|
|
*/
|
|
flags = clk_enable_lock();
|
|
clk->ops = &clk_nodrv_ops;
|
|
clk_enable_unlock(flags);
|
|
|
|
if (!hlist_empty(&clk->children)) {
|
|
struct clk *child;
|
|
|
|
/* Reparent all children to the orphan list. */
|
|
hlist_for_each_entry(child, &clk->children, child_node)
|
|
clk_set_parent(child, NULL);
|
|
}
|
|
|
|
clk_debug_unregister(clk);
|
|
|
|
hlist_del_init(&clk->child_node);
|
|
|
|
if (clk->prepare_count)
|
|
pr_warn("%s: unregistering prepared clock: %s\n",
|
|
__func__, clk->name);
|
|
|
|
kref_put(&clk->ref, __clk_release);
|
|
out:
|
|
clk_prepare_unlock();
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_unregister);
|
|
|
|
static void devm_clk_release(struct device *dev, void *res)
|
|
{
|
|
clk_unregister(res);
|
|
}
|
|
|
|
/**
|
|
* devm_clk_register - resource managed clk_register()
|
|
* @dev: device that is registering this clock
|
|
* @hw: link to hardware-specific clock data
|
|
*
|
|
* Managed clk_register(). Clocks returned from this function are
|
|
* automatically clk_unregister()ed on driver detach. See clk_register() for
|
|
* more information.
|
|
*/
|
|
struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
|
|
{
|
|
struct clk *clk;
|
|
int ret;
|
|
|
|
clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
|
|
if (!clk)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ret = _clk_register(dev, hw, clk);
|
|
if (!ret) {
|
|
devres_add(dev, clk);
|
|
} else {
|
|
devres_free(clk);
|
|
clk = ERR_PTR(ret);
|
|
}
|
|
|
|
return clk;
|
|
}
|
|
EXPORT_SYMBOL_GPL(devm_clk_register);
|
|
|
|
static int devm_clk_match(struct device *dev, void *res, void *data)
|
|
{
|
|
struct clk *c = res;
|
|
if (WARN_ON(!c))
|
|
return 0;
|
|
return c == data;
|
|
}
|
|
|
|
/**
|
|
* devm_clk_unregister - resource managed clk_unregister()
|
|
* @clk: clock to unregister
|
|
*
|
|
* Deallocate a clock allocated with devm_clk_register(). Normally
|
|
* this function will not need to be called and the resource management
|
|
* code will ensure that the resource is freed.
|
|
*/
|
|
void devm_clk_unregister(struct device *dev, struct clk *clk)
|
|
{
|
|
WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
|
|
}
|
|
EXPORT_SYMBOL_GPL(devm_clk_unregister);
|
|
|
|
/*
|
|
* clkdev helpers
|
|
*/
|
|
int __clk_get(struct clk *clk)
|
|
{
|
|
if (clk) {
|
|
if (!try_module_get(clk->owner))
|
|
return 0;
|
|
|
|
kref_get(&clk->ref);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
void __clk_put(struct clk *clk)
|
|
{
|
|
if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
|
|
return;
|
|
|
|
clk_prepare_lock();
|
|
kref_put(&clk->ref, __clk_release);
|
|
clk_prepare_unlock();
|
|
|
|
module_put(clk->owner);
|
|
}
|
|
|
|
/*** clk rate change notifiers ***/
|
|
|
|
/**
|
|
* clk_notifier_register - add a clk rate change notifier
|
|
* @clk: struct clk * to watch
|
|
* @nb: struct notifier_block * with callback info
|
|
*
|
|
* Request notification when clk's rate changes. This uses an SRCU
|
|
* notifier because we want it to block and notifier unregistrations are
|
|
* uncommon. The callbacks associated with the notifier must not
|
|
* re-enter into the clk framework by calling any top-level clk APIs;
|
|
* this will cause a nested prepare_lock mutex.
|
|
*
|
|
* Pre-change notifier callbacks will be passed the current, pre-change
|
|
* rate of the clk via struct clk_notifier_data.old_rate. The new,
|
|
* post-change rate of the clk is passed via struct
|
|
* clk_notifier_data.new_rate.
|
|
*
|
|
* Post-change notifiers will pass the now-current, post-change rate of
|
|
* the clk in both struct clk_notifier_data.old_rate and struct
|
|
* clk_notifier_data.new_rate.
|
|
*
|
|
* Abort-change notifiers are effectively the opposite of pre-change
|
|
* notifiers: the original pre-change clk rate is passed in via struct
|
|
* clk_notifier_data.new_rate and the failed post-change rate is passed
|
|
* in via struct clk_notifier_data.old_rate.
|
|
*
|
|
* clk_notifier_register() must be called from non-atomic context.
|
|
* Returns -EINVAL if called with null arguments, -ENOMEM upon
|
|
* allocation failure; otherwise, passes along the return value of
|
|
* srcu_notifier_chain_register().
|
|
*/
|
|
int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
|
|
{
|
|
struct clk_notifier *cn;
|
|
int ret = -ENOMEM;
|
|
|
|
if (!clk || !nb)
|
|
return -EINVAL;
|
|
|
|
clk_prepare_lock();
|
|
|
|
/* search the list of notifiers for this clk */
|
|
list_for_each_entry(cn, &clk_notifier_list, node)
|
|
if (cn->clk == clk)
|
|
break;
|
|
|
|
/* if clk wasn't in the notifier list, allocate new clk_notifier */
|
|
if (cn->clk != clk) {
|
|
cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
|
|
if (!cn)
|
|
goto out;
|
|
|
|
cn->clk = clk;
|
|
srcu_init_notifier_head(&cn->notifier_head);
|
|
|
|
list_add(&cn->node, &clk_notifier_list);
|
|
}
|
|
|
|
ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
|
|
|
|
clk->notifier_count++;
|
|
|
|
out:
|
|
clk_prepare_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_notifier_register);
|
|
|
|
/**
|
|
* clk_notifier_unregister - remove a clk rate change notifier
|
|
* @clk: struct clk *
|
|
* @nb: struct notifier_block * with callback info
|
|
*
|
|
* Request no further notification for changes to 'clk' and frees memory
|
|
* allocated in clk_notifier_register.
|
|
*
|
|
* Returns -EINVAL if called with null arguments; otherwise, passes
|
|
* along the return value of srcu_notifier_chain_unregister().
|
|
*/
|
|
int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
|
|
{
|
|
struct clk_notifier *cn = NULL;
|
|
int ret = -EINVAL;
|
|
|
|
if (!clk || !nb)
|
|
return -EINVAL;
|
|
|
|
clk_prepare_lock();
|
|
|
|
list_for_each_entry(cn, &clk_notifier_list, node)
|
|
if (cn->clk == clk)
|
|
break;
|
|
|
|
if (cn->clk == clk) {
|
|
ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
|
|
|
|
clk->notifier_count--;
|
|
|
|
/* XXX the notifier code should handle this better */
|
|
if (!cn->notifier_head.head) {
|
|
srcu_cleanup_notifier_head(&cn->notifier_head);
|
|
list_del(&cn->node);
|
|
kfree(cn);
|
|
}
|
|
|
|
} else {
|
|
ret = -ENOENT;
|
|
}
|
|
|
|
clk_prepare_unlock();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_notifier_unregister);
|
|
|
|
#ifdef CONFIG_OF
|
|
/**
|
|
* struct of_clk_provider - Clock provider registration structure
|
|
* @link: Entry in global list of clock providers
|
|
* @node: Pointer to device tree node of clock provider
|
|
* @get: Get clock callback. Returns NULL or a struct clk for the
|
|
* given clock specifier
|
|
* @data: context pointer to be passed into @get callback
|
|
*/
|
|
struct of_clk_provider {
|
|
struct list_head link;
|
|
|
|
struct device_node *node;
|
|
struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
|
|
void *data;
|
|
};
|
|
|
|
static const struct of_device_id __clk_of_table_sentinel
|
|
__used __section(__clk_of_table_end);
|
|
|
|
static LIST_HEAD(of_clk_providers);
|
|
static DEFINE_MUTEX(of_clk_mutex);
|
|
|
|
/* of_clk_provider list locking helpers */
|
|
void of_clk_lock(void)
|
|
{
|
|
mutex_lock(&of_clk_mutex);
|
|
}
|
|
|
|
void of_clk_unlock(void)
|
|
{
|
|
mutex_unlock(&of_clk_mutex);
|
|
}
|
|
|
|
struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
|
|
void *data)
|
|
{
|
|
return data;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
|
|
|
|
struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
|
|
{
|
|
struct clk_onecell_data *clk_data = data;
|
|
unsigned int idx = clkspec->args[0];
|
|
|
|
if (idx >= clk_data->clk_num) {
|
|
pr_err("%s: invalid clock index %d\n", __func__, idx);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
return clk_data->clks[idx];
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
|
|
|
|
/**
|
|
* of_clk_add_provider() - Register a clock provider for a node
|
|
* @np: Device node pointer associated with clock provider
|
|
* @clk_src_get: callback for decoding clock
|
|
* @data: context pointer for @clk_src_get callback.
|
|
*/
|
|
int of_clk_add_provider(struct device_node *np,
|
|
struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
|
|
void *data),
|
|
void *data)
|
|
{
|
|
struct of_clk_provider *cp;
|
|
|
|
cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
|
|
if (!cp)
|
|
return -ENOMEM;
|
|
|
|
cp->node = of_node_get(np);
|
|
cp->data = data;
|
|
cp->get = clk_src_get;
|
|
|
|
mutex_lock(&of_clk_mutex);
|
|
list_add(&cp->link, &of_clk_providers);
|
|
mutex_unlock(&of_clk_mutex);
|
|
pr_debug("Added clock from %s\n", np->full_name);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_clk_add_provider);
|
|
|
|
/**
|
|
* of_clk_del_provider() - Remove a previously registered clock provider
|
|
* @np: Device node pointer associated with clock provider
|
|
*/
|
|
void of_clk_del_provider(struct device_node *np)
|
|
{
|
|
struct of_clk_provider *cp;
|
|
|
|
mutex_lock(&of_clk_mutex);
|
|
list_for_each_entry(cp, &of_clk_providers, link) {
|
|
if (cp->node == np) {
|
|
list_del(&cp->link);
|
|
of_node_put(cp->node);
|
|
kfree(cp);
|
|
break;
|
|
}
|
|
}
|
|
mutex_unlock(&of_clk_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_clk_del_provider);
|
|
|
|
struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec)
|
|
{
|
|
struct of_clk_provider *provider;
|
|
struct clk *clk = ERR_PTR(-ENOENT);
|
|
|
|
/* Check if we have such a provider in our array */
|
|
list_for_each_entry(provider, &of_clk_providers, link) {
|
|
if (provider->node == clkspec->np)
|
|
clk = provider->get(clkspec, provider->data);
|
|
if (!IS_ERR(clk))
|
|
break;
|
|
}
|
|
|
|
return clk;
|
|
}
|
|
|
|
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
|
|
{
|
|
struct clk *clk;
|
|
|
|
mutex_lock(&of_clk_mutex);
|
|
clk = __of_clk_get_from_provider(clkspec);
|
|
mutex_unlock(&of_clk_mutex);
|
|
|
|
return clk;
|
|
}
|
|
|
|
int of_clk_get_parent_count(struct device_node *np)
|
|
{
|
|
return of_count_phandle_with_args(np, "clocks", "#clock-cells");
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
|
|
|
|
const char *of_clk_get_parent_name(struct device_node *np, int index)
|
|
{
|
|
struct of_phandle_args clkspec;
|
|
const char *clk_name;
|
|
int rc;
|
|
|
|
if (index < 0)
|
|
return NULL;
|
|
|
|
rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
|
|
&clkspec);
|
|
if (rc)
|
|
return NULL;
|
|
|
|
if (of_property_read_string_index(clkspec.np, "clock-output-names",
|
|
clkspec.args_count ? clkspec.args[0] : 0,
|
|
&clk_name) < 0)
|
|
clk_name = clkspec.np->name;
|
|
|
|
of_node_put(clkspec.np);
|
|
return clk_name;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
|
|
|
|
/**
|
|
* of_clk_init() - Scan and init clock providers from the DT
|
|
* @matches: array of compatible values and init functions for providers.
|
|
*
|
|
* This function scans the device tree for matching clock providers and
|
|
* calls their initialization functions
|
|
*/
|
|
void __init of_clk_init(const struct of_device_id *matches)
|
|
{
|
|
const struct of_device_id *match;
|
|
struct device_node *np;
|
|
|
|
if (!matches)
|
|
matches = &__clk_of_table;
|
|
|
|
for_each_matching_node_and_match(np, matches, &match) {
|
|
of_clk_init_cb_t clk_init_cb = match->data;
|
|
clk_init_cb(np);
|
|
}
|
|
}
|
|
#endif
|