diff options
Diffstat (limited to 'drivers/clk/clk.c')
| -rw-r--r-- | drivers/clk/clk.c | 2626 |
1 files changed, 2626 insertions, 0 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c new file mode 100644 index 00000000000..8b73edef151 --- /dev/null +++ b/drivers/clk/clk.c @@ -0,0 +1,2626 @@ +/* + * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> + * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Standard functionality for the common clock API. See Documentation/clk.txt + */ + +#include <linux/clk-private.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> +#include <linux/err.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/device.h> +#include <linux/init.h> +#include <linux/sched.h> + +#include "clk.h" + +static DEFINE_SPINLOCK(enable_lock); +static DEFINE_MUTEX(prepare_lock); + +static struct task_struct *prepare_owner; +static struct task_struct *enable_owner; + +static int prepare_refcnt; +static int enable_refcnt; + +static HLIST_HEAD(clk_root_list); +static HLIST_HEAD(clk_orphan_list); +static LIST_HEAD(clk_notifier_list); + +/*** locking ***/ +static void clk_prepare_lock(void) +{ + if (!mutex_trylock(&prepare_lock)) { + if (prepare_owner == current) { + prepare_refcnt++; + return; + } + mutex_lock(&prepare_lock); + } + WARN_ON_ONCE(prepare_owner != NULL); + WARN_ON_ONCE(prepare_refcnt != 0); + prepare_owner = current; + prepare_refcnt = 1; +} + +static void clk_prepare_unlock(void) +{ + WARN_ON_ONCE(prepare_owner != current); + WARN_ON_ONCE(prepare_refcnt == 0); + + if (--prepare_refcnt) + return; + prepare_owner = NULL; + mutex_unlock(&prepare_lock); +} + +static unsigned long clk_enable_lock(void) +{ + unsigned long flags; + + if (!spin_trylock_irqsave(&enable_lock, flags)) { + if (enable_owner == current) { + enable_refcnt++; + return flags; + } + spin_lock_irqsave(&enable_lock, flags); + } + WARN_ON_ONCE(enable_owner != NULL); + WARN_ON_ONCE(enable_refcnt != 0); + enable_owner = current; + enable_refcnt = 1; + return flags; +} + +static void clk_enable_unlock(unsigned long flags) +{ + WARN_ON_ONCE(enable_owner != current); + WARN_ON_ONCE(enable_refcnt == 0); + + if (--enable_refcnt) + return; + enable_owner = NULL; + spin_unlock_irqrestore(&enable_lock, flags); +} + +/*** debugfs support ***/ + +#ifdef CONFIG_DEBUG_FS +#include <linux/debugfs.h> + +static struct dentry *rootdir; +static struct dentry *orphandir; +static int inited = 0; + +static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level) +{ + if (!c) + return; + + seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu\n", + level * 3 + 1, "", + 30 - level * 3, c->name, + c->enable_count, c->prepare_count, clk_get_rate(c), + clk_get_accuracy(c)); +} + +static void clk_summary_show_subtree(struct seq_file *s, struct clk *c, + int level) +{ + struct clk *child; + + if (!c) + return; + + clk_summary_show_one(s, c, level); + + hlist_for_each_entry(child, &c->children, child_node) + clk_summary_show_subtree(s, child, level + 1); +} + +static int clk_summary_show(struct seq_file *s, void *data) +{ + struct clk *c; + + seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy\n"); + seq_puts(s, "--------------------------------------------------------------------------------\n"); + + clk_prepare_lock(); + + hlist_for_each_entry(c, &clk_root_list, child_node) + clk_summary_show_subtree(s, c, 0); + + hlist_for_each_entry(c, &clk_orphan_list, child_node) + clk_summary_show_subtree(s, c, 0); + + clk_prepare_unlock(); + + return 0; +} + + +static int clk_summary_open(struct inode *inode, struct file *file) +{ + return single_open(file, clk_summary_show, inode->i_private); +} + +static const struct file_operations clk_summary_fops = { + .open = clk_summary_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static void clk_dump_one(struct seq_file *s, struct clk *c, int level) +{ + if (!c) + return; + + seq_printf(s, "\"%s\": { ", c->name); + seq_printf(s, "\"enable_count\": %d,", c->enable_count); + seq_printf(s, "\"prepare_count\": %d,", c->prepare_count); + seq_printf(s, "\"rate\": %lu", clk_get_rate(c)); + seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c)); +} + +static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level) +{ + struct clk *child; + + if (!c) + return; + + clk_dump_one(s, c, level); + + hlist_for_each_entry(child, &c->children, child_node) { + seq_printf(s, ","); + clk_dump_subtree(s, child, level + 1); + } + + seq_printf(s, "}"); +} + +static int clk_dump(struct seq_file *s, void *data) +{ + struct clk *c; + bool first_node = true; + + seq_printf(s, "{"); + + clk_prepare_lock(); + + hlist_for_each_entry(c, &clk_root_list, child_node) { + if (!first_node) + seq_printf(s, ","); + first_node = false; + clk_dump_subtree(s, c, 0); + } + + hlist_for_each_entry(c, &clk_orphan_list, child_node) { + seq_printf(s, ","); + clk_dump_subtree(s, c, 0); + } + + clk_prepare_unlock(); + + seq_printf(s, "}"); + return 0; +} + + +static int clk_dump_open(struct inode *inode, struct file *file) +{ + return single_open(file, clk_dump, inode->i_private); +} + +static const struct file_operations clk_dump_fops = { + .open = clk_dump_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/* caller must hold prepare_lock */ +static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) +{ + struct dentry *d; + int ret = -ENOMEM; + + if (!clk || !pdentry) { + ret = -EINVAL; + goto out; + } + + d = debugfs_create_dir(clk->name, pdentry); + if (!d) + goto out; + + clk->dentry = d; + + d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry, + (u32 *)&clk->rate); + if (!d) + goto err_out; + + d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry, + (u32 *)&clk->accuracy); + if (!d) + goto err_out; + + d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry, + (u32 *)&clk->flags); + if (!d) + goto err_out; + + d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry, + (u32 *)&clk->prepare_count); + if (!d) + goto err_out; + + d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry, + (u32 *)&clk->enable_count); + if (!d) + goto err_out; + + d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry, + (u32 *)&clk->notifier_count); + if (!d) + goto err_out; + + if (clk->ops->debug_init) + if (clk->ops->debug_init(clk->hw, clk->dentry)) + goto err_out; + + ret = 0; + goto out; + +err_out: + debugfs_remove_recursive(clk->dentry); + clk->dentry = NULL; +out: + return ret; +} + +/* caller must hold prepare_lock */ +static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry) +{ + struct clk *child; + int ret = -EINVAL;; + + if (!clk || !pdentry) + goto out; + + ret = clk_debug_create_one(clk, pdentry); + + if (ret) + goto out; + + hlist_for_each_entry(child, &clk->children, child_node) + clk_debug_create_subtree(child, clk->dentry); + + ret = 0; +out: + return ret; +} + +/** + * clk_debug_register - add a clk node to the debugfs clk tree + * @clk: the clk being added to the debugfs clk tree + * + * Dynamically adds a clk to the debugfs clk tree if debugfs has been + * initialized. Otherwise it bails out early since the debugfs clk tree + * will be created lazily by clk_debug_init as part of a late_initcall. + * + * Caller must hold prepare_lock. Only clk_init calls this function (so + * far) so this is taken care. + */ +static int clk_debug_register(struct clk *clk) +{ + struct clk *parent; + struct dentry *pdentry; + int ret = 0; + + if (!inited) + goto out; + + parent = clk->parent; + + /* + * Check to see if a clk is a root clk. Also check that it is + * safe to add this clk to debugfs + */ + if (!parent) + if (clk->flags & CLK_IS_ROOT) + pdentry = rootdir; + else + pdentry = orphandir; + else + if (parent->dentry) + pdentry = parent->dentry; + else + goto out; + + ret = clk_debug_create_subtree(clk, pdentry); + +out: + return ret; +} + + /** + * clk_debug_unregister - remove a clk node from the debugfs clk tree + * @clk: the clk being removed from the debugfs clk tree + * + * Dynamically removes a clk and all it's children clk nodes from the + * debugfs clk tree if clk->dentry points to debugfs created by + * clk_debug_register in __clk_init. + * + * Caller must hold prepare_lock. + */ +static void clk_debug_unregister(struct clk *clk) +{ + debugfs_remove_recursive(clk->dentry); +} + +/** + * clk_debug_reparent - reparent clk node in the debugfs clk tree + * @clk: the clk being reparented + * @new_parent: the new clk parent, may be NULL + * + * Rename clk entry in the debugfs clk tree if debugfs has been + * initialized. Otherwise it bails out early since the debugfs clk tree + * will be created lazily by clk_debug_init as part of a late_initcall. + * + * Caller must hold prepare_lock. + */ +static void clk_debug_reparent(struct clk *clk, struct clk *new_parent) +{ + struct dentry *d; + struct dentry *new_parent_d; + + if (!inited) + return; + + if (new_parent) + new_parent_d = new_parent->dentry; + else + new_parent_d = orphandir; + + d = debugfs_rename(clk->dentry->d_parent, clk->dentry, + new_parent_d, clk->name); + if (d) + clk->dentry = d; + else + pr_debug("%s: failed to rename debugfs entry for %s\n", + __func__, clk->name); +} + +/** + * clk_debug_init - lazily create the debugfs clk tree visualization + * + * clks are often initialized very early during boot before memory can + * be dynamically allocated and well before debugfs is setup. + * clk_debug_init walks the clk tree hierarchy while holding + * prepare_lock and creates the topology as part of a late_initcall, + * thus insuring that clks initialized very early will still be + * represented in the debugfs clk tree. This function should only be + * called once at boot-time, and all other clks added dynamically will + * be done so with clk_debug_register. + */ +static int __init clk_debug_init(void) +{ + struct clk *clk; + struct dentry *d; + + rootdir = debugfs_create_dir("clk", NULL); + + if (!rootdir) + return -ENOMEM; + + d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL, + &clk_summary_fops); + if (!d) + return -ENOMEM; + + d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL, + &clk_dump_fops); + if (!d) + return -ENOMEM; + + orphandir = debugfs_create_dir("orphans", rootdir); + + if (!orphandir) + return -ENOMEM; + + clk_prepare_lock(); + + hlist_for_each_entry(clk, &clk_root_list, child_node) + clk_debug_create_subtree(clk, rootdir); + + hlist_for_each_entry(clk, &clk_orphan_list, child_node) + clk_debug_create_subtree(clk, orphandir); + + inited = 1; + + clk_prepare_unlock(); + + return 0; +} +late_initcall(clk_debug_init); +#else +static inline int clk_debug_register(struct clk *clk) { return 0; } +static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent) +{ +} +static inline void clk_debug_unregister(struct clk *clk) +{ +} +#endif + +/* caller must hold prepare_lock */ +static void clk_unprepare_unused_subtree(struct clk *clk) +{ + struct clk *child; + + if (!clk) + return; + + hlist_for_each_entry(child, &clk->children, child_node) + clk_unprepare_unused_subtree(child); + + if (clk->prepare_count) + return; + + if (clk->flags & CLK_IGNORE_UNUSED) + return; + + if (__clk_is_prepared(clk)) { + if (clk->ops->unprepare_unused) + clk->ops->unprepare_unused(clk->hw); + else if (clk->ops->unprepare) + clk->ops->unprepare(clk->hw); + } +} + +/* caller must hold prepare_lock */ +static void clk_disable_unused_subtree(struct clk *clk) +{ + struct clk *child; + unsigned long flags; + + if (!clk) + goto out; + + hlist_for_each_entry(child, &clk->children, child_node) + clk_disable_unused_subtree(child); + + flags = clk_enable_lock(); + + if (clk->enable_count) + goto unlock_out; + + if (clk->flags & CLK_IGNORE_UNUSED) + goto unlock_out; + + /* + * some gate clocks have special needs during the disable-unused + * sequence. call .disable_unused if available, otherwise fall + * back to .disable + */ + if (__clk_is_enabled(clk)) { + if (clk->ops->disable_unused) + clk->ops->disable_unused(clk->hw); + else if (clk->ops->disable) + clk->ops->disable(clk->hw); + } + +unlock_out: + clk_enable_unlock(flags); + +out: + return; +} + +static bool clk_ignore_unused; +static int __init clk_ignore_unused_setup(char *__unused) +{ + clk_ignore_unused = true; + return 1; +} +__setup("clk_ignore_unused", clk_ignore_unused_setup); + +static int clk_disable_unused(void) +{ + struct clk *clk; + + if (clk_ignore_unused) { + pr_warn("clk: Not disabling unused clocks\n"); + return 0; + } + + clk_prepare_lock(); + + hlist_for_each_entry(clk, &clk_root_list, child_node) + clk_disable_unused_subtree(clk); + + hlist_for_each_entry(clk, &clk_orphan_list, child_node) + 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) +{ + if (IS_ERR_OR_NULL(clk)) + return; + + 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(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; + + if (IS_ERR_OR_NULL(clk)) + return; + + 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; +} +EXPORT_SYMBOL_GPL(__clk_round_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); + +static unsigned long clk_recalc(struct clk *clk, unsigned long parent_rate) +{ + if (clk->ops->recalc_rate) + return clk->ops->recalc_rate(clk->hw, parent_rate); + return parent_rate; +} + +/** + * __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; + + clk->rate = clk_recalc(clk, 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; + + new_rate = clk_recalc(clk, 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) { + pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n", + __func__, clk->name, ret); + 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) { + child->new_rate = clk_recalc(child, 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); + + clk->rate = clk_recalc(clk, 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_debug("%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; + + /* 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); + +/** + * 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 i, 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; + } + + 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 clk; + +fail_parent_names_copy: + while (--i >= 0) + kfree(clk->parent_names[i]); + kfree(clk->parent_names); +fail_parent_names: + kfree(clk->name); +fail_name: + 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; + struct hlist_node *t; + + /* Reparent all children to the orphan list. */ + hlist_for_each_entry_safe(child, t, &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(*(struct clk **)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; + struct clk **clkp; + + clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL); + if (!clkp) + return ERR_PTR(-ENOMEM); + + clk = clk_register(dev, hw); + if (!IS_ERR(clk)) { + *clkp = clk; + devres_add(dev, clkp); + } else { + devres_free(clkp); + } + + 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. + * + * In all notification cases cases (pre, post and abort rate change) the + * original clock rate is passed to the callback via struct + * clk_notifier_data.old_rate and the new frequency is passed via struct + * clk_notifier_data.new_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(-EPROBE_DEFER); + + /* 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; + struct property *prop; + const char *clk_name; + const __be32 *vp; + u32 pv; + int rc; + int count; + + if (index < 0) + return NULL; + + rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, + &clkspec); + if (rc) + return NULL; + + index = clkspec.args_count ? clkspec.args[0] : 0; + count = 0; + + /* if there is an indices property, use it to transfer the index + * specified into an array offset for the clock-output-names property. + */ + of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) { + if (index == pv) { + index = count; + break; + } + count++; + } + + if (of_property_read_string_index(clkspec.np, "clock-output-names", + index, + &clk_name) < 0) + clk_name = clkspec.np->name; + + of_node_put(clkspec.np); + return clk_name; +} +EXPORT_SYMBOL_GPL(of_clk_get_parent_name); + +struct clock_provider { + of_clk_init_cb_t clk_init_cb; + struct device_node *np; + struct list_head node; +}; + +static LIST_HEAD(clk_provider_list); + +/* + * This function looks for a parent clock. If there is one, then it + * checks that the provider for this parent clock was initialized, in + * this case the parent clock will be ready. + */ +static int parent_ready(struct device_node *np) +{ + int i = 0; + + while (true) { + struct clk *clk = of_clk_get(np, i); + + /* this parent is ready we can check the next one */ + if (!IS_ERR(clk)) { + clk_put(clk); + i++; + continue; + } + + /* at least one parent is not ready, we exit now */ + if (PTR_ERR(clk) == -EPROBE_DEFER) + return 0; + + /* + * Here we make assumption that the device tree is + * written correctly. So an error means that there is + * no more parent. As we didn't exit yet, then the + * previous parent are ready. If there is no clock + * parent, no need to wait for them, then we can + * consider their absence as being ready + */ + return 1; + } +} + +/** + * 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. It also does it by trying + * to follow the dependencies. + */ +void __init of_clk_init(const struct of_device_id *matches) +{ + const struct of_device_id *match; + struct device_node *np; + struct clock_provider *clk_provider, *next; + bool is_init_done; + bool force = false; + + if (!matches) + matches = &__clk_of_table; + + /* First prepare the list of the clocks providers */ + for_each_matching_node_and_match(np, matches, &match) { + struct clock_provider *parent = + kzalloc(sizeof(struct clock_provider), GFP_KERNEL); + + parent->clk_init_cb = match->data; + parent->np = np; + list_add_tail(&parent->node, &clk_provider_list); + } + + while (!list_empty(&clk_provider_list)) { + is_init_done = false; + list_for_each_entry_safe(clk_provider, next, + &clk_provider_list, node) { + if (force || parent_ready(clk_provider->np)) { + clk_provider->clk_init_cb(clk_provider->np); + list_del(&clk_provider->node); + kfree(clk_provider); + is_init_done = true; + } + } + + /* + * We didn't manage to initialize any of the + * remaining providers during the last loop, so now we + * initialize all the remaining ones unconditionally + * in case the clock parent was not mandatory + */ + if (!is_init_done) + force = true; + + } +} +#endif |