diff options
Diffstat (limited to 'drivers/clk/clk.c')
| -rw-r--r-- | drivers/clk/clk.c | 1094 |
1 files changed, 795 insertions, 299 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 934cfd18f72..8b73edef151 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -21,6 +21,8 @@ #include <linux/init.h> #include <linux/sched.h> +#include "clk.h" + static DEFINE_SPINLOCK(enable_lock); static DEFINE_MUTEX(prepare_lock); @@ -92,7 +94,7 @@ static void clk_enable_unlock(unsigned long flags) /*** debugfs support ***/ -#ifdef CONFIG_COMMON_CLK_DEBUG +#ifdef CONFIG_DEBUG_FS #include <linux/debugfs.h> static struct dentry *rootdir; @@ -104,11 +106,11 @@ 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 %-10lu", + seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu\n", level * 3 + 1, "", 30 - level * 3, c->name, - c->enable_count, c->prepare_count, c->rate); - seq_printf(s, "\n"); + 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, @@ -129,8 +131,8 @@ static int clk_summary_show(struct seq_file *s, void *data) { struct clk *c; - seq_printf(s, " clock enable_cnt prepare_cnt rate\n"); - seq_printf(s, "---------------------------------------------------------------------\n"); + seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy\n"); + seq_puts(s, "--------------------------------------------------------------------------------\n"); clk_prepare_lock(); @@ -166,7 +168,8 @@ static void clk_dump_one(struct seq_file *s, struct clk *c, int level) 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", c->rate); + 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) @@ -248,6 +251,11 @@ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) 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) @@ -268,11 +276,16 @@ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) 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(clk->dentry); + debugfs_remove_recursive(clk->dentry); + clk->dentry = NULL; out: return ret; } @@ -342,6 +355,21 @@ 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 @@ -432,6 +460,9 @@ 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 */ @@ -458,7 +489,6 @@ static void clk_unprepare_unused_subtree(struct clk *clk) clk->ops->unprepare(clk->hw); } } -EXPORT_SYMBOL_GPL(__clk_get_flags); /* caller must hold prepare_lock */ static void clk_disable_unused_subtree(struct clk *clk) @@ -534,7 +564,7 @@ static int clk_disable_unused(void) return 0; } -late_initcall(clk_disable_unused); +late_initcall_sync(clk_disable_unused); /*** helper functions ***/ @@ -548,16 +578,33 @@ 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) { @@ -589,11 +636,21 @@ unsigned long __clk_get_rate(struct clk *clk) 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) { @@ -636,6 +693,7 @@ bool __clk_is_enabled(struct clk *clk) out: return !!ret; } +EXPORT_SYMBOL_GPL(__clk_is_enabled); static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk) { @@ -679,6 +737,56 @@ struct clk *__clk_lookup(const char *name) 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) @@ -702,7 +810,7 @@ void __clk_unprepare(struct clk *clk) /** * clk_unprepare - undo preparation of a clock source - * @clk: the clk being unprepare + * @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 @@ -713,6 +821,9 @@ void __clk_unprepare(struct clk *clk) */ void clk_unprepare(struct clk *clk) { + if (IS_ERR_OR_NULL(clk)) + return; + clk_prepare_lock(); __clk_unprepare(clk); clk_prepare_unlock(); @@ -774,9 +885,6 @@ 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; @@ -805,6 +913,9 @@ 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); @@ -869,28 +980,33 @@ 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; - if (!clk->ops->round_rate) { - if (clk->flags & CLK_SET_RATE_PARENT) - return __clk_round_rate(clk->parent, rate); - else - return clk->rate; - } - - if (clk->parent) - parent_rate = clk->parent->rate; - - return clk->ops->round_rate(clk->hw, rate, &parent_rate); + 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 @@ -950,13 +1066,73 @@ static int __clk_notify(struct clk *clk, unsigned long msg, } /** + * __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 it's parent. + * 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. @@ -974,10 +1150,7 @@ static void __clk_recalc_rates(struct clk *clk, unsigned long msg) 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; + clk->rate = clk_recalc(clk, parent_rate); /* * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE @@ -1014,6 +1187,138 @@ unsigned long clk_get_rate(struct clk *clk) } 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 @@ -1026,7 +1331,7 @@ EXPORT_SYMBOL_GPL(clk_get_rate); * 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 it's parent. + * take on the rate of its parent. * * Caller must hold prepare_lock. */ @@ -1036,17 +1341,17 @@ static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate) 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; + 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) + 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); @@ -1058,18 +1363,22 @@ out: return ret; } -static void clk_calc_subtree(struct clk *clk, unsigned long new_rate) +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); + child->new_rate = clk_recalc(child, new_rate); + clk_calc_subtree(child, child->new_rate, NULL, 0); } } @@ -1080,50 +1389,63 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate) 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 */ - if (clk->parent) - best_parent_rate = clk->parent->rate; - - /* never propagate up to the parent */ - if (!(clk->flags & CLK_SET_RATE_PARENT)) { - if (!clk->ops->round_rate) { - clk->new_rate = clk->rate; - return NULL; - } - new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); + 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; } - /* need clk->parent from here on out */ - if (!clk->parent) { - pr_debug("%s: %s has NULL parent\n", __func__, clk->name); + /* 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; } - if (!clk->ops->round_rate) { - top = clk_calc_new_rates(clk->parent, rate); - new_rate = clk->parent->new_rate; - - goto out; + /* 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; + } } - new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); - - if (best_parent_rate != clk->parent->rate) { - top = clk_calc_new_rates(clk->parent, best_parent_rate); - - goto out; - } + 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); + clk_calc_subtree(clk, new_rate, parent, p_index); return top; } @@ -1135,7 +1457,7 @@ out: */ static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event) { - struct clk *child, *fail_clk = NULL; + struct clk *child, *tmp_clk, *fail_clk = NULL; int ret = NOTIFY_DONE; if (clk->rate == clk->new_rate) @@ -1148,9 +1470,19 @@ static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long even } hlist_for_each_entry(child, &clk->children, child_node) { - clk = clk_propagate_rate_change(child, event); - if (clk) - fail_clk = clk; + /* 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; @@ -1165,25 +1497,49 @@ 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->parent) + if (clk->new_parent) + best_parent_rate = clk->new_parent->rate; + else if (clk->parent) best_parent_rate = clk->parent->rate; - if (clk->ops->set_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; + 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) + 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); } /** @@ -1198,7 +1554,7 @@ static void clk_change_rate(struct clk *clk) * 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 it's rate. Upward propagation will continue + * 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. * @@ -1212,11 +1568,14 @@ 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->rate) + if (rate == clk_get_rate(clk)) goto out; if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) { @@ -1234,7 +1593,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate) /* 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__, + pr_debug("%s: failed to set %s rate\n", __func__, fail_clk->name); clk_propagate_rate_change(top, ABORT_RATE_CHANGE); ret = -EBUSY; @@ -1312,158 +1671,48 @@ static struct clk *__clk_init_parent(struct clk *clk) if (!clk->parents) clk->parents = - kzalloc((sizeof(struct clk*) * clk->num_parents), + kcalloc(clk->num_parents, sizeof(struct clk *), GFP_KERNEL); - if (!clk->parents) - ret = __clk_lookup(clk->parent_names[index]); - else if (!clk->parents[index]) - ret = clk->parents[index] = - __clk_lookup(clk->parent_names[index]); - else - ret = clk->parents[index]; + ret = clk_get_parent_by_index(clk, index); out: return ret; } -static void clk_reparent(struct clk *clk, struct clk *new_parent) -{ - hlist_del(&clk->child_node); - - if (new_parent) - hlist_add_head(&clk->child_node, &new_parent->children); - else - hlist_add_head(&clk->child_node, &clk_orphan_list); - - clk->parent = new_parent; -} - 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); } -static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent) -{ - u8 i; - - if (!clk->parents) - clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), - GFP_KERNEL); - - /* - * 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 && clk->parents[i] == parent) - break; - else if (!strcmp(clk->parent_names[i], parent->name)) { - if (clk->parents) - clk->parents[i] = __clk_lookup(parent->name); - break; - } - } - - return i; -} - -static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index) -{ - unsigned long flags; - int ret = 0; - struct clk *old_parent = clk->parent; - bool migrated_enable = false; - - /* migrate prepare */ - if (clk->prepare_count) - __clk_prepare(parent); - - flags = clk_enable_lock(); - - /* migrate enable */ - if (clk->enable_count) { - __clk_enable(parent); - migrated_enable = true; - } - - /* update the clk tree topology */ - clk_reparent(clk, parent); - - clk_enable_unlock(flags); - - /* change clock input source */ - if (parent && clk->ops->set_parent) - ret = clk->ops->set_parent(clk->hw, p_index); - - if (ret) { - /* - * The error handling is tricky due to that we need to release - * the spinlock while issuing the .set_parent callback. This - * means the new parent might have been enabled/disabled in - * between, which must be considered when doing rollback. - */ - flags = clk_enable_lock(); - - clk_reparent(clk, old_parent); - - if (migrated_enable && clk->enable_count) { - __clk_disable(parent); - } else if (migrated_enable && (clk->enable_count == 0)) { - __clk_disable(old_parent); - } else if (!migrated_enable && clk->enable_count) { - __clk_disable(parent); - __clk_enable(old_parent); - } - - clk_enable_unlock(flags); - - if (clk->prepare_count) - __clk_unprepare(parent); - - return ret; - } - - /* clean up enable for old parent if migration was done */ - if (migrated_enable) { - flags = clk_enable_lock(); - __clk_disable(old_parent); - clk_enable_unlock(flags); - } - - /* clean up prepare for old parent if migration was done */ - if (clk->prepare_count) - __clk_unprepare(old_parent); - - /* update debugfs with new clk tree topology */ - clk_debug_reparent(clk, parent); - return 0; -} - /** * 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 it's new input source. If clk has the - * CLK_SET_PARENT_GATE flag set then clk must be gated for this - * operation to succeed. 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. + * 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; - u8 p_index = 0; + int p_index = 0; unsigned long p_rate = 0; - if (!clk || !clk->ops) - return -EINVAL; + if (!clk) + return 0; /* verify ops for for multi-parent clks */ if ((clk->num_parents > 1) && (!clk->ops->set_parent)) @@ -1485,17 +1734,16 @@ int clk_set_parent(struct clk *clk, struct clk *parent) if (parent) { p_index = clk_fetch_parent_index(clk, parent); p_rate = parent->rate; - if (p_index == clk->num_parents) { + if (p_index < 0) { pr_debug("%s: clk %s can not be parent of clk %s\n", __func__, parent->name, clk->name); - ret = -EINVAL; + ret = p_index; goto out; } } /* propagate PRE_RATE_CHANGE notifications */ - if (clk->notifier_count) - ret = __clk_speculate_rates(clk, p_rate); + ret = __clk_speculate_rates(clk, p_rate); /* abort if a driver objects */ if (ret & NOTIFY_STOP_MASK) @@ -1504,11 +1752,13 @@ int clk_set_parent(struct clk *clk, struct clk *parent) /* do the re-parent */ ret = __clk_set_parent(clk, parent, p_index); - /* propagate rate recalculation accordingly */ - if (ret) + /* propagate rate an accuracy recalculation accordingly */ + if (ret) { __clk_recalc_rates(clk, ABORT_RATE_CHANGE); - else + } else { __clk_recalc_rates(clk, POST_RATE_CHANGE); + __clk_recalc_accuracies(clk); + } out: clk_prepare_unlock(); @@ -1546,8 +1796,9 @@ int __clk_init(struct device *dev, struct clk *clk) /* check that clk_ops are sane. See Documentation/clk.txt */ if (clk->ops->set_rate && - !(clk->ops->round_rate && clk->ops->recalc_rate)) { - pr_warning("%s: %s must implement .round_rate & .recalc_rate\n", + !((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; @@ -1560,6 +1811,14 @@ int __clk_init(struct device *dev, struct clk *clk) 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], @@ -1577,8 +1836,8 @@ int __clk_init(struct device *dev, struct clk *clk) * for clock drivers to statically initialize clk->parents. */ if (clk->num_parents > 1 && !clk->parents) { - clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), - GFP_KERNEL); + 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 @@ -1612,6 +1871,21 @@ int __clk_init(struct device *dev, struct clk *clk) 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) @@ -1625,12 +1899,13 @@ int __clk_init(struct device *dev, struct clk *clk) 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->ops->get_parent) { + 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); @@ -1650,13 +1925,12 @@ int __clk_init(struct device *dev, struct clk *clk) * 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 it's use is discouraged. + * using this callback, as its use is discouraged. */ if (clk->ops->init) clk->ops->init(clk->hw); - clk_debug_register(clk); - + kref_init(&clk->ref); out: clk_prepare_unlock(); @@ -1677,7 +1951,7 @@ out: * 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 it's operations. Returns 0 + * 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) @@ -1692,6 +1966,10 @@ struct clk *__clk_register(struct device *dev, struct 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) @@ -1701,9 +1979,28 @@ struct clk *__clk_register(struct device *dev, struct clk_hw *hw) } EXPORT_SYMBOL_GPL(__clk_register); -static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk) +/** + * 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) { @@ -1712,14 +2009,16 @@ static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk) 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 = kzalloc((sizeof(char*) * clk->num_parents), - GFP_KERNEL); + 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__); @@ -1741,7 +2040,7 @@ static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk) ret = __clk_init(dev, clk); if (!ret) - return 0; + return clk; fail_parent_names_copy: while (--i >= 0) @@ -1750,54 +2049,116 @@ fail_parent_names_copy: fail_parent_names: kfree(clk->name); fail_name: - return ret; + kfree(clk); +fail_out: + return ERR_PTR(ret); } +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. +/* + * Free memory allocated for a clock. + * Caller must hold prepare_lock. */ -struct clk *clk_register(struct device *dev, struct clk_hw *hw) +static void __clk_release(struct kref *ref) { - 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; - } + struct clk *clk = container_of(ref, struct clk, ref); + int i = clk->num_parents; - ret = _clk_register(dev, hw, clk); - if (!ret) - return clk; + kfree(clk->parents); + while (--i >= 0) + kfree(clk->parent_names[i]); + kfree(clk->parent_names); + kfree(clk->name); kfree(clk); -fail_out: - return ERR_PTR(ret); } -EXPORT_SYMBOL_GPL(clk_register); + +/* + * 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 - * - * Currently unimplemented. */ -void clk_unregister(struct clk *clk) {} +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(res); + clk_unregister(*(struct clk **)res); } /** @@ -1812,18 +2173,18 @@ static void devm_clk_release(struct device *dev, void *res) struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw) { struct clk *clk; - int ret; + struct clk **clkp; - clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL); - if (!clk) + clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL); + if (!clkp) return ERR_PTR(-ENOMEM); - ret = _clk_register(dev, hw, clk); - if (!ret) { - devres_add(dev, clk); + clk = clk_register(dev, hw); + if (!IS_ERR(clk)) { + *clkp = clk; + devres_add(dev, clkp); } else { - devres_free(clk); - clk = ERR_PTR(ret); + devres_free(clkp); } return clk; @@ -1852,6 +2213,32 @@ void devm_clk_unregister(struct device *dev, struct clk *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 ***/ /** @@ -1865,20 +2252,11 @@ EXPORT_SYMBOL_GPL(devm_clk_unregister); * 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 + * 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. * - * 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 @@ -1955,6 +2333,7 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) /* 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); } @@ -1985,13 +2364,22 @@ struct of_clk_provider { void *data; }; -extern struct of_device_id __clk_of_table[]; - 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_lock); +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) @@ -2035,9 +2423,9 @@ int of_clk_add_provider(struct device_node *np, cp->data = data; cp->get = clk_src_get; - mutex_lock(&of_clk_lock); + mutex_lock(&of_clk_mutex); list_add(&cp->link, &of_clk_providers); - mutex_unlock(&of_clk_lock); + mutex_unlock(&of_clk_mutex); pr_debug("Added clock from %s\n", np->full_name); return 0; @@ -2052,7 +2440,7 @@ void of_clk_del_provider(struct device_node *np) { struct of_clk_provider *cp; - mutex_lock(&of_clk_lock); + mutex_lock(&of_clk_mutex); list_for_each_entry(cp, &of_clk_providers, link) { if (cp->node == np) { list_del(&cp->link); @@ -2061,33 +2449,52 @@ void of_clk_del_provider(struct device_node *np) break; } } - mutex_unlock(&of_clk_lock); + 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 clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec) { struct of_clk_provider *provider; - struct clk *clk = ERR_PTR(-ENOENT); + struct clk *clk = ERR_PTR(-EPROBE_DEFER); /* Check if we have such a provider in our array */ - mutex_lock(&of_clk_lock); 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; } - mutex_unlock(&of_clk_lock); 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; @@ -2097,8 +2504,22 @@ const char *of_clk_get_parent_name(struct device_node *np, int index) 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", - clkspec.args_count ? clkspec.args[0] : 0, + index, &clk_name) < 0) clk_name = clkspec.np->name; @@ -2107,24 +2528,99 @@ const char *of_clk_get_parent_name(struct device_node *np, int index) } 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 + * 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; + 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; - for_each_matching_node(np, matches) { - const struct of_device_id *match = of_match_node(matches, np); - of_clk_init_cb_t clk_init_cb = match->data; - clk_init_cb(np); } } #endif |