/* * Copyright (C) 2010-2011 Canonical Ltd * Copyright (C) 2011-2012 Linaro Ltd * * 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 #include #include #include #include #include #include #include #include #include #include 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 #include 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 %-10lu", level * 3 + 1, "", 30 - level * 3, c->name, c->enable_count, c->prepare_count, clk_get_rate(c)); seq_printf(s, "\n"); } 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_printf(s, " clock enable_cnt prepare_cnt rate\n"); seq_printf(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)); } 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_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; ret = 0; goto out; err_out: debugfs_remove(clk->dentry); 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_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) { } #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); } } EXPORT_SYMBOL_GPL(__clk_get_flags); /* 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; } u8 __clk_get_num_parents(struct clk *clk) { return !clk ? 0 : clk->num_parents; } struct clk *__clk_get_parent(struct clk *clk) { return !clk ? NULL : clk->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]; } 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; } 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; 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; } 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; } /*** clk api ***/ void __clk_unprepare(struct clk *clk) { if (!clk) return; if (WARN_ON(clk->prepare_count == 0)) return; if (--clk->prepare_count > 0) return; WARN_ON(clk->enable_count > 0); if (clk->ops->unprepare) clk->ops->unprepare(clk->hw); __clk_unprepare(clk->parent); } /** * clk_unprepare - undo preparation of a clock source * @clk: the clk being unprepared * * clk_unprepare may sleep, which differentiates it from clk_disable. In a * simple case, clk_unprepare can be used instead of clk_disable to gate a clk * if the operation may sleep. One example is a clk which is accessed over * I2c. In the complex case a clk gate operation may require a fast and a slow * part. It is this reason that clk_unprepare and clk_disable are not mutually * exclusive. In fact clk_disable must be called before clk_unprepare. */ void clk_unprepare(struct clk *clk) { clk_prepare_lock(); __clk_unprepare(clk); clk_prepare_unlock(); } EXPORT_SYMBOL_GPL(clk_unprepare); int __clk_prepare(struct clk *clk) { int ret = 0; if (!clk) return 0; if (clk->prepare_count == 0) { ret = __clk_prepare(clk->parent); if (ret) return ret; if (clk->ops->prepare) { ret = clk->ops->prepare(clk->hw); if (ret) { __clk_unprepare(clk->parent); return ret; } } } clk->prepare_count++; return 0; } /** * clk_prepare - prepare a clock source * @clk: the clk being prepared * * clk_prepare may sleep, which differentiates it from clk_enable. In a simple * case, clk_prepare can be used instead of clk_enable to ungate a clk if the * operation may sleep. One example is a clk which is accessed over I2c. In * the complex case a clk ungate operation may require a fast and a slow part. * It is this reason that clk_prepare and clk_enable are not mutually * exclusive. In fact clk_prepare must be called before clk_enable. * Returns 0 on success, -EERROR otherwise. */ int clk_prepare(struct clk *clk) { int ret; clk_prepare_lock(); ret = __clk_prepare(clk); clk_prepare_unlock(); return ret; } EXPORT_SYMBOL_GPL(clk_prepare); static void __clk_disable(struct clk *clk) { if (!clk) return; if (WARN_ON(IS_ERR(clk))) return; if (WARN_ON(clk->enable_count == 0)) return; if (--clk->enable_count > 0) return; if (clk->ops->disable) clk->ops->disable(clk->hw); __clk_disable(clk->parent); } /** * clk_disable - gate a clock * @clk: the clk being gated * * clk_disable must not sleep, which differentiates it from clk_unprepare. In * a simple case, clk_disable can be used instead of clk_unprepare to gate a * clk if the operation is fast and will never sleep. One example is a * SoC-internal clk which is controlled via simple register writes. In the * complex case a clk gate operation may require a fast and a slow part. It is * this reason that clk_unprepare and clk_disable are not mutually exclusive. * In fact clk_disable must be called before clk_unprepare. */ void clk_disable(struct clk *clk) { unsigned long flags; flags = clk_enable_lock(); __clk_disable(clk); clk_enable_unlock(flags); } EXPORT_SYMBOL_GPL(clk_disable); static int __clk_enable(struct clk *clk) { int ret = 0; if (!clk) return 0; if (WARN_ON(clk->prepare_count == 0)) return -ESHUTDOWN; if (clk->enable_count == 0) { ret = __clk_enable(clk->parent); if (ret) return ret; if (clk->ops->enable) { ret = clk->ops->enable(clk->hw); if (ret) { __clk_disable(clk->parent); return ret; } } } clk->enable_count++; return 0; } /** * clk_enable - ungate a clock * @clk: the clk being ungated * * clk_enable must not sleep, which differentiates it from clk_prepare. In a * simple case, clk_enable can be used instead of clk_prepare to ungate a clk * if the operation will never sleep. One example is a SoC-internal clk which * is controlled via simple register writes. In the complex case a clk ungate * operation may require a fast and a slow part. It is this reason that * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare * must be called before clk_enable. Returns 0 on success, -EERROR * otherwise. */ int clk_enable(struct clk *clk) { unsigned long flags; int ret; flags = clk_enable_lock(); ret = __clk_enable(clk); clk_enable_unlock(flags); return ret; } EXPORT_SYMBOL_GPL(clk_enable); /** * __clk_round_rate - round the given rate for a clk * @clk: round the rate of this clock * @rate: the rate which is to be rounded * * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate */ unsigned long __clk_round_rate(struct clk *clk, unsigned long rate) { unsigned long parent_rate = 0; struct clk *parent; if (!clk) return 0; parent = clk->parent; if (parent) parent_rate = parent->rate; if (clk->ops->determine_rate) return clk->ops->determine_rate(clk->hw, rate, &parent_rate, &parent); else if (clk->ops->round_rate) return clk->ops->round_rate(clk->hw, rate, &parent_rate); else if (clk->flags & CLK_SET_RATE_PARENT) return __clk_round_rate(clk->parent, rate); else return clk->rate; } /** * clk_round_rate - round the given rate for a clk * @clk: the clk for which we are rounding a rate * @rate: the rate which is to be rounded * * Takes in a rate as input and rounds it to a rate that the clk can actually * use which is then returned. If clk doesn't support round_rate operation * then the parent rate is returned. */ long clk_round_rate(struct clk *clk, unsigned long rate) { unsigned long ret; clk_prepare_lock(); ret = __clk_round_rate(clk, rate); clk_prepare_unlock(); return ret; } EXPORT_SYMBOL_GPL(clk_round_rate); /** * __clk_notify - call clk notifier chain * @clk: struct clk * that is changing rate * @msg: clk notifier type (see include/linux/clk.h) * @old_rate: old clk rate * @new_rate: new clk rate * * Triggers a notifier call chain on the clk rate-change notification * for 'clk'. Passes a pointer to the struct clk and the previous * and current rates to the notifier callback. Intended to be called by * internal clock code only. Returns NOTIFY_DONE from the last driver * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if * a driver returns that. */ static int __clk_notify(struct clk *clk, unsigned long msg, unsigned long old_rate, unsigned long new_rate) { struct clk_notifier *cn; struct clk_notifier_data cnd; int ret = NOTIFY_DONE; cnd.clk = clk; cnd.old_rate = old_rate; cnd.new_rate = new_rate; list_for_each_entry(cn, &clk_notifier_list, node) { if (cn->clk == clk) { ret = srcu_notifier_call_chain(&cn->notifier_head, msg, &cnd); break; } } return ret; } /** * __clk_recalc_rates * @clk: first clk in the subtree * @msg: notification type (see include/linux/clk.h) * * Walks the subtree of clks starting with clk and recalculates rates as it * goes. Note that if a clk does not implement the .recalc_rate callback then * it is assumed that the clock will take on the rate of its parent. * * clk_recalc_rates also propagates the POST_RATE_CHANGE notification, * if necessary. * * Caller must hold prepare_lock. */ static void __clk_recalc_rates(struct clk *clk, unsigned long msg) { unsigned long old_rate; unsigned long parent_rate = 0; struct clk *child; old_rate = clk->rate; if (clk->parent) parent_rate = clk->parent->rate; if (clk->ops->recalc_rate) clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate); else clk->rate = parent_rate; /* * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE * & ABORT_RATE_CHANGE notifiers */ if (clk->notifier_count && msg) __clk_notify(clk, msg, old_rate, clk->rate); hlist_for_each_entry(child, &clk->children, child_node) __clk_recalc_rates(child, msg); } /** * clk_get_rate - return the rate of clk * @clk: the clk whose rate is being returned * * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag * is set, which means a recalc_rate will be issued. * If clk is NULL then returns 0. */ unsigned long clk_get_rate(struct clk *clk) { unsigned long rate; clk_prepare_lock(); if (clk && (clk->flags & CLK_GET_RATE_NOCACHE)) __clk_recalc_rates(clk, 0); rate = __clk_get_rate(clk); clk_prepare_unlock(); return rate; } EXPORT_SYMBOL_GPL(clk_get_rate); static 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 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 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; /* * 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); /* 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; } /* * 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); return 0; } /** * __clk_speculate_rates * @clk: first clk in the subtree * @parent_rate: the "future" rate of clk's parent * * Walks the subtree of clks starting with clk, speculating rates as it * goes and firing off PRE_RATE_CHANGE notifications as necessary. * * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending * pre-rate change notifications and returns early if no clks in the * subtree have subscribed to the notifications. Note that if a clk does not * implement the .recalc_rate callback then it is assumed that the clock will * take on the rate of its parent. * * Caller must hold prepare_lock. */ static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate) { struct clk *child; unsigned long new_rate; int ret = NOTIFY_DONE; if (clk->ops->recalc_rate) new_rate = clk->ops->recalc_rate(clk->hw, parent_rate); else new_rate = parent_rate; /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */ if (clk->notifier_count) ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate); if (ret & NOTIFY_STOP_MASK) goto out; hlist_for_each_entry(child, &clk->children, child_node) { ret = __clk_speculate_rates(child, new_rate); if (ret & NOTIFY_STOP_MASK) break; } out: return ret; } static void clk_calc_subtree(struct clk *clk, unsigned long new_rate, struct clk *new_parent, u8 p_index) { struct clk *child; clk->new_rate = new_rate; clk->new_parent = new_parent; clk->new_parent_index = p_index; /* include clk in new parent's PRE_RATE_CHANGE notifications */ clk->new_child = NULL; if (new_parent && new_parent != clk->parent) new_parent->new_child = clk; hlist_for_each_entry(child, &clk->children, child_node) { if (child->ops->recalc_rate) child->new_rate = child->ops->recalc_rate(child->hw, new_rate); else child->new_rate = new_rate; clk_calc_subtree(child, child->new_rate, NULL, 0); } } /* * calculate the new rates returning the topmost clock that has to be * changed. */ static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) { struct clk *top = clk; struct clk *old_parent, *parent; unsigned long best_parent_rate = 0; unsigned long new_rate; u8 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 == clk->num_parents) { 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; old_rate = clk->rate; /* set parent */ if (clk->new_parent && clk->new_parent != clk->parent) __clk_set_parent(clk, clk->new_parent, clk->new_parent_index); if (clk->parent) best_parent_rate = clk->parent->rate; if (clk->ops->set_rate) clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate); if (clk->ops->recalc_rate) clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate); else clk->rate = best_parent_rate; if (clk->notifier_count && old_rate != clk->rate) __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); hlist_for_each_entry(child, &clk->children, child_node) { /* Skip children who will be reparented to another clock */ if (child->new_parent && child->new_parent != clk) continue; clk_change_rate(child); } /* handle the new child who might not be in clk->children yet */ if (clk->new_child) clk_change_rate(clk->new_child); } /** * clk_set_rate - specify a new rate for clk * @clk: the clk whose rate is being changed * @rate: the new rate for clk * * In the simplest case clk_set_rate will only adjust the rate of clk. * * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to * propagate up to clk's parent; whether or not this happens depends on the * outcome of clk's .round_rate implementation. If *parent_rate is unchanged * after calling .round_rate then upstream parent propagation is ignored. If * *parent_rate comes back with a new rate for clk's parent then we propagate * up to clk's parent and set its rate. Upward propagation will continue * until either a clk does not support the CLK_SET_RATE_PARENT flag or * .round_rate stops requesting changes to clk's parent_rate. * * Rate changes are accomplished via tree traversal that also recalculates the * rates for the clocks and fires off POST_RATE_CHANGE notifiers. * * Returns 0 on success, -EERROR otherwise. */ int clk_set_rate(struct clk *clk, unsigned long rate) { struct clk *top, *fail_clk; int ret = 0; if (!clk) return 0; /* prevent racing with updates to the clock topology */ clk_prepare_lock(); /* bail early if nothing to do */ if (rate == clk_get_rate(clk)) goto out; if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) { ret = -EBUSY; goto out; } /* calculate new rates and get the topmost changed clock */ top = clk_calc_new_rates(clk, rate); if (!top) { ret = -EINVAL; goto out; } /* notify that we are about to change rates */ fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE); if (fail_clk) { pr_warn("%s: failed to set %s rate\n", __func__, fail_clk->name); clk_propagate_rate_change(top, ABORT_RATE_CHANGE); ret = -EBUSY; goto out; } /* change the rates */ clk_change_rate(top); out: clk_prepare_unlock(); return ret; } EXPORT_SYMBOL_GPL(clk_set_rate); /** * clk_get_parent - return the parent of a clk * @clk: the clk whose parent gets returned * * Simply returns clk->parent. Returns NULL if clk is NULL. */ struct clk *clk_get_parent(struct clk *clk) { struct clk *parent; clk_prepare_lock(); parent = __clk_get_parent(clk); clk_prepare_unlock(); return parent; } EXPORT_SYMBOL_GPL(clk_get_parent); /* * .get_parent is mandatory for clocks with multiple possible parents. It is * optional for single-parent clocks. Always call .get_parent if it is * available and WARN if it is missing for multi-parent clocks. * * For single-parent clocks without .get_parent, first check to see if the * .parents array exists, and if so use it to avoid an expensive tree * traversal. If .parents does not exist then walk the tree with __clk_lookup. */ static struct clk *__clk_init_parent(struct clk *clk) { struct clk *ret = NULL; u8 index; /* handle the trivial cases */ if (!clk->num_parents) goto out; if (clk->num_parents == 1) { if (IS_ERR_OR_NULL(clk->parent)) ret = clk->parent = __clk_lookup(clk->parent_names[0]); ret = clk->parent; goto out; } if (!clk->ops->get_parent) { WARN(!clk->ops->get_parent, "%s: multi-parent clocks must implement .get_parent\n", __func__); goto out; }; /* * Do our best to cache parent clocks in clk->parents. This prevents * unnecessary and expensive calls to __clk_lookup. We don't set * clk->parent here; that is done by the calling function */ index = clk->ops->get_parent(clk->hw); if (!clk->parents) clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), 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_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; u8 p_index = 0; unsigned long p_rate = 0; if (!clk) return 0; if (!clk->ops) return -EINVAL; /* verify ops for for multi-parent clks */ if ((clk->num_parents > 1) && (!clk->ops->set_parent)) return -ENOSYS; /* prevent racing with updates to the clock topology */ clk_prepare_lock(); if (clk->parent == parent) goto out; /* check that we are allowed to re-parent if the clock is in use */ if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) { ret = -EBUSY; goto out; } /* try finding the new parent index */ if (parent) { p_index = clk_fetch_parent_index(clk, parent); p_rate = parent->rate; if (p_index == clk->num_parents) { pr_debug("%s: clk %s can not be parent of clk %s\n", __func__, parent->name, clk->name); ret = -EINVAL; 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 recalculation accordingly */ if (ret) __clk_recalc_rates(clk, ABORT_RATE_CHANGE); else __clk_recalc_rates(clk, POST_RATE_CHANGE); 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; } /* 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 = kzalloc((sizeof(struct clk*) * clk->num_parents), 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 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; /* * 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) { 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); clk_debug_register(clk); 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; ret = __clk_init(dev, clk); if (ret) return ERR_PTR(ret); return clk; } EXPORT_SYMBOL_GPL(__clk_register); static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk) { int i, ret; clk->name = kstrdup(hw->init->name, GFP_KERNEL); if (!clk->name) { pr_err("%s: could not allocate clk->name\n", __func__); ret = -ENOMEM; goto fail_name; } clk->ops = hw->init->ops; 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); if (!clk->parent_names) { pr_err("%s: could not allocate clk->parent_names\n", __func__); ret = -ENOMEM; goto fail_parent_names; } /* copy each string name in case parent_names is __initdata */ for (i = 0; i < clk->num_parents; i++) { clk->parent_names[i] = kstrdup(hw->init->parent_names[i], GFP_KERNEL); if (!clk->parent_names[i]) { pr_err("%s: could not copy parent_names\n", __func__); ret = -ENOMEM; goto fail_parent_names_copy; } } ret = __clk_init(dev, clk); if (!ret) return 0; fail_parent_names_copy: while (--i >= 0) kfree(clk->parent_names[i]); kfree(clk->parent_names); fail_parent_names: kfree(clk->name); fail_name: return ret; } /** * clk_register - allocate a new clock, register it and return an opaque cookie * @dev: device that is registering this clock * @hw: link to hardware-specific clock data * * clk_register is the primary interface for populating the clock tree with new * clock nodes. It returns a pointer to the newly allocated struct clk which * cannot be dereferenced by driver code but may be used in conjuction with the * rest of the clock API. In the event of an error clk_register will return an * error code; drivers must test for an error code after calling clk_register. */ struct clk *clk_register(struct device *dev, struct clk_hw *hw) { int ret; struct clk *clk; clk = kzalloc(sizeof(*clk), GFP_KERNEL); if (!clk) { pr_err("%s: could not allocate clk\n", __func__); ret = -ENOMEM; goto fail_out; } ret = _clk_register(dev, hw, clk); if (!ret) return clk; kfree(clk); fail_out: return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(clk_register); /** * clk_unregister - unregister a currently registered clock * @clk: clock to unregister * * Currently unimplemented. */ void clk_unregister(struct clk *clk) {} EXPORT_SYMBOL_GPL(clk_unregister); static void devm_clk_release(struct device *dev, void *res) { clk_unregister(res); } /** * devm_clk_register - resource managed clk_register() * @dev: device that is registering this clock * @hw: link to hardware-specific clock data * * Managed clk_register(). Clocks returned from this function are * automatically clk_unregister()ed on driver detach. See clk_register() for * more information. */ struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw) { struct clk *clk; int ret; clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL); if (!clk) return ERR_PTR(-ENOMEM); ret = _clk_register(dev, hw, clk); if (!ret) { devres_add(dev, clk); } else { devres_free(clk); clk = ERR_PTR(ret); } return clk; } EXPORT_SYMBOL_GPL(devm_clk_register); static int devm_clk_match(struct device *dev, void *res, void *data) { struct clk *c = res; if (WARN_ON(!c)) return 0; return c == data; } /** * devm_clk_unregister - resource managed clk_unregister() * @clk: clock to unregister * * Deallocate a clock allocated with devm_clk_register(). Normally * this function will not need to be called and the resource management * code will ensure that the resource is freed. */ void devm_clk_unregister(struct device *dev, struct clk *clk) { WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk)); } EXPORT_SYMBOL_GPL(devm_clk_unregister); /*** clk rate change notifiers ***/ /** * clk_notifier_register - add a clk rate change notifier * @clk: struct clk * to watch * @nb: struct notifier_block * with callback info * * Request notification when clk's rate changes. This uses an SRCU * notifier because we want it to block and notifier unregistrations are * uncommon. The callbacks associated with the notifier must not * re-enter into the clk framework by calling any top-level clk APIs; * this will cause a nested prepare_lock mutex. * * Pre-change notifier callbacks will be passed the current, pre-change * rate of the clk via struct clk_notifier_data.old_rate. The new, * post-change rate of the clk is passed via struct * clk_notifier_data.new_rate. * * Post-change notifiers will pass the now-current, post-change rate of * the clk in both struct clk_notifier_data.old_rate and struct * clk_notifier_data.new_rate. * * Abort-change notifiers are effectively the opposite of pre-change * notifiers: the original pre-change clk rate is passed in via struct * clk_notifier_data.new_rate and the failed post-change rate is passed * in via struct clk_notifier_data.old_rate. * * clk_notifier_register() must be called from non-atomic context. * Returns -EINVAL if called with null arguments, -ENOMEM upon * allocation failure; otherwise, passes along the return value of * srcu_notifier_chain_register(). */ int clk_notifier_register(struct clk *clk, struct notifier_block *nb) { struct clk_notifier *cn; int ret = -ENOMEM; if (!clk || !nb) return -EINVAL; clk_prepare_lock(); /* search the list of notifiers for this clk */ list_for_each_entry(cn, &clk_notifier_list, node) if (cn->clk == clk) break; /* if clk wasn't in the notifier list, allocate new clk_notifier */ if (cn->clk != clk) { cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL); if (!cn) goto out; cn->clk = clk; srcu_init_notifier_head(&cn->notifier_head); list_add(&cn->node, &clk_notifier_list); } ret = srcu_notifier_chain_register(&cn->notifier_head, nb); clk->notifier_count++; out: clk_prepare_unlock(); return ret; } EXPORT_SYMBOL_GPL(clk_notifier_register); /** * clk_notifier_unregister - remove a clk rate change notifier * @clk: struct clk * * @nb: struct notifier_block * with callback info * * Request no further notification for changes to 'clk' and frees memory * allocated in clk_notifier_register. * * Returns -EINVAL if called with null arguments; otherwise, passes * along the return value of srcu_notifier_chain_unregister(). */ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) { struct clk_notifier *cn = NULL; int ret = -EINVAL; if (!clk || !nb) return -EINVAL; clk_prepare_lock(); list_for_each_entry(cn, &clk_notifier_list, node) if (cn->clk == clk) break; if (cn->clk == clk) { ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); clk->notifier_count--; /* XXX the notifier code should handle this better */ if (!cn->notifier_head.head) { srcu_cleanup_notifier_head(&cn->notifier_head); list_del(&cn->node); kfree(cn); } } else { ret = -ENOENT; } clk_prepare_unlock(); return ret; } EXPORT_SYMBOL_GPL(clk_notifier_unregister); #ifdef CONFIG_OF /** * struct of_clk_provider - Clock provider registration structure * @link: Entry in global list of clock providers * @node: Pointer to device tree node of clock provider * @get: Get clock callback. Returns NULL or a struct clk for the * given clock specifier * @data: context pointer to be passed into @get callback */ struct of_clk_provider { struct list_head link; struct device_node *node; struct clk *(*get)(struct of_phandle_args *clkspec, void *data); void *data; }; 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); 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_lock); list_add(&cp->link, &of_clk_providers); mutex_unlock(&of_clk_lock); 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_lock); 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_lock); } EXPORT_SYMBOL_GPL(of_clk_del_provider); struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) { struct of_clk_provider *provider; struct clk *clk = ERR_PTR(-ENOENT); /* Check if we have such a provider in our array */ 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; } const char *of_clk_get_parent_name(struct device_node *np, int index) { struct of_phandle_args clkspec; const char *clk_name; int rc; if (index < 0) return NULL; rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, &clkspec); if (rc) return NULL; if (of_property_read_string_index(clkspec.np, "clock-output-names", clkspec.args_count ? clkspec.args[0] : 0, &clk_name) < 0) clk_name = clkspec.np->name; of_node_put(clkspec.np); return clk_name; } EXPORT_SYMBOL_GPL(of_clk_get_parent_name); /** * of_clk_init() - Scan and init clock providers from the DT * @matches: array of compatible values and init functions for providers. * * This function scans the device tree for matching clock providers and * calls their initialization functions */ void __init of_clk_init(const struct of_device_id *matches) { const struct of_device_id *match; struct device_node *np; if (!matches) matches = __clk_of_table; for_each_matching_node_and_match(np, matches, &match) { of_clk_init_cb_t clk_init_cb = match->data; clk_init_cb(np); } } #endif