diff options
Diffstat (limited to 'drivers/clk/clk.c')
| -rw-r--r-- | drivers/clk/clk.c | 193 |
1 files changed, 154 insertions, 39 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index ed87b2405806..0230c9d95975 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -19,14 +19,77 @@ #include <linux/of.h> #include <linux/device.h> #include <linux/init.h> +#include <linux/sched.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_COMMON_CLK_DEBUG @@ -69,7 +132,7 @@ static int clk_summary_show(struct seq_file *s, void *data) seq_printf(s, " clock enable_cnt prepare_cnt rate\n"); seq_printf(s, "---------------------------------------------------------------------\n"); - mutex_lock(&prepare_lock); + clk_prepare_lock(); hlist_for_each_entry(c, &clk_root_list, child_node) clk_summary_show_subtree(s, c, 0); @@ -77,7 +140,7 @@ static int clk_summary_show(struct seq_file *s, void *data) hlist_for_each_entry(c, &clk_orphan_list, child_node) clk_summary_show_subtree(s, c, 0); - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return 0; } @@ -130,7 +193,7 @@ static int clk_dump(struct seq_file *s, void *data) seq_printf(s, "{"); - mutex_lock(&prepare_lock); + clk_prepare_lock(); hlist_for_each_entry(c, &clk_root_list, child_node) { if (!first_node) @@ -144,7 +207,7 @@ static int clk_dump(struct seq_file *s, void *data) clk_dump_subtree(s, c, 0); } - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); seq_printf(s, "}"); return 0; @@ -316,7 +379,7 @@ static int __init clk_debug_init(void) if (!orphandir) return -ENOMEM; - mutex_lock(&prepare_lock); + clk_prepare_lock(); hlist_for_each_entry(clk, &clk_root_list, child_node) clk_debug_create_subtree(clk, rootdir); @@ -326,7 +389,7 @@ static int __init clk_debug_init(void) inited = 1; - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return 0; } @@ -336,6 +399,31 @@ static inline int clk_debug_register(struct clk *clk) { return 0; } #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; @@ -347,7 +435,7 @@ static void clk_disable_unused_subtree(struct clk *clk) hlist_for_each_entry(child, &clk->children, child_node) clk_disable_unused_subtree(child); - spin_lock_irqsave(&enable_lock, flags); + flags = clk_enable_lock(); if (clk->enable_count) goto unlock_out; @@ -368,7 +456,7 @@ static void clk_disable_unused_subtree(struct clk *clk) } unlock_out: - spin_unlock_irqrestore(&enable_lock, flags); + clk_enable_unlock(flags); out: return; @@ -378,7 +466,7 @@ static int clk_disable_unused(void) { struct clk *clk; - mutex_lock(&prepare_lock); + clk_prepare_lock(); hlist_for_each_entry(clk, &clk_root_list, child_node) clk_disable_unused_subtree(clk); @@ -386,7 +474,13 @@ static int clk_disable_unused(void) hlist_for_each_entry(clk, &clk_orphan_list, child_node) clk_disable_unused_subtree(clk); - mutex_unlock(&prepare_lock); + 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; } @@ -451,6 +545,27 @@ unsigned long __clk_get_flags(struct clk *clk) return !clk ? 0 : clk->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; @@ -548,9 +663,9 @@ void __clk_unprepare(struct clk *clk) */ void clk_unprepare(struct clk *clk) { - mutex_lock(&prepare_lock); + clk_prepare_lock(); __clk_unprepare(clk); - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); } EXPORT_SYMBOL_GPL(clk_unprepare); @@ -596,9 +711,9 @@ int clk_prepare(struct clk *clk) { int ret; - mutex_lock(&prepare_lock); + clk_prepare_lock(); ret = __clk_prepare(clk); - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return ret; } @@ -640,9 +755,9 @@ void clk_disable(struct clk *clk) { unsigned long flags; - spin_lock_irqsave(&enable_lock, flags); + flags = clk_enable_lock(); __clk_disable(clk); - spin_unlock_irqrestore(&enable_lock, flags); + clk_enable_unlock(flags); } EXPORT_SYMBOL_GPL(clk_disable); @@ -693,9 +808,9 @@ int clk_enable(struct clk *clk) unsigned long flags; int ret; - spin_lock_irqsave(&enable_lock, flags); + flags = clk_enable_lock(); ret = __clk_enable(clk); - spin_unlock_irqrestore(&enable_lock, flags); + clk_enable_unlock(flags); return ret; } @@ -740,9 +855,9 @@ long clk_round_rate(struct clk *clk, unsigned long rate) { unsigned long ret; - mutex_lock(&prepare_lock); + clk_prepare_lock(); ret = __clk_round_rate(clk, rate); - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return ret; } @@ -837,13 +952,13 @@ unsigned long clk_get_rate(struct clk *clk) { unsigned long rate; - mutex_lock(&prepare_lock); + clk_prepare_lock(); if (clk && (clk->flags & CLK_GET_RATE_NOCACHE)) __clk_recalc_rates(clk, 0); rate = __clk_get_rate(clk); - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return rate; } @@ -974,7 +1089,7 @@ static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long even int ret = NOTIFY_DONE; if (clk->rate == clk->new_rate) - return 0; + return NULL; if (clk->notifier_count) { ret = __clk_notify(clk, event, clk->rate, clk->new_rate); @@ -1048,7 +1163,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate) int ret = 0; /* prevent racing with updates to the clock topology */ - mutex_lock(&prepare_lock); + clk_prepare_lock(); /* bail early if nothing to do */ if (rate == clk->rate) @@ -1080,7 +1195,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate) clk_change_rate(top); out: - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return ret; } @@ -1096,9 +1211,9 @@ struct clk *clk_get_parent(struct clk *clk) { struct clk *parent; - mutex_lock(&prepare_lock); + clk_prepare_lock(); parent = __clk_get_parent(clk); - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return parent; } @@ -1242,19 +1357,19 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent) __clk_prepare(parent); /* FIXME replace with clk_is_enabled(clk) someday */ - spin_lock_irqsave(&enable_lock, flags); + flags = clk_enable_lock(); if (clk->enable_count) __clk_enable(parent); - spin_unlock_irqrestore(&enable_lock, flags); + clk_enable_unlock(flags); /* change clock input source */ ret = clk->ops->set_parent(clk->hw, i); /* clean up old prepare and enable */ - spin_lock_irqsave(&enable_lock, flags); + flags = clk_enable_lock(); if (clk->enable_count) __clk_disable(old_parent); - spin_unlock_irqrestore(&enable_lock, flags); + clk_enable_unlock(flags); if (clk->prepare_count) __clk_unprepare(old_parent); @@ -1286,7 +1401,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent) return -ENOSYS; /* prevent racing with updates to the clock topology */ - mutex_lock(&prepare_lock); + clk_prepare_lock(); if (clk->parent == parent) goto out; @@ -1315,7 +1430,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent) __clk_reparent(clk, parent); out: - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return ret; } @@ -1338,7 +1453,7 @@ int __clk_init(struct device *dev, struct clk *clk) if (!clk) return -EINVAL; - mutex_lock(&prepare_lock); + clk_prepare_lock(); /* check to see if a clock with this name is already registered */ if (__clk_lookup(clk->name)) { @@ -1462,7 +1577,7 @@ int __clk_init(struct device *dev, struct clk *clk) clk_debug_register(clk); out: - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return ret; } @@ -1696,7 +1811,7 @@ int clk_notifier_register(struct clk *clk, struct notifier_block *nb) if (!clk || !nb) return -EINVAL; - mutex_lock(&prepare_lock); + clk_prepare_lock(); /* search the list of notifiers for this clk */ list_for_each_entry(cn, &clk_notifier_list, node) @@ -1720,7 +1835,7 @@ int clk_notifier_register(struct clk *clk, struct notifier_block *nb) clk->notifier_count++; out: - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return ret; } @@ -1745,7 +1860,7 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) if (!clk || !nb) return -EINVAL; - mutex_lock(&prepare_lock); + clk_prepare_lock(); list_for_each_entry(cn, &clk_notifier_list, node) if (cn->clk == clk) @@ -1766,7 +1881,7 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) ret = -ENOENT; } - mutex_unlock(&prepare_lock); + clk_prepare_unlock(); return ret; } |