| /* |
| * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> |
| * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * Standard functionality for the common clock API. See Documentation/clk.txt |
| */ |
| |
| #include <linux/clk.h> |
| #include <linux/clk-provider.h> |
| #include <linux/clk/clk-conf.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/spinlock.h> |
| #include <linux/err.h> |
| #include <linux/list.h> |
| #include <linux/slab.h> |
| #include <linux/of.h> |
| #include <linux/device.h> |
| #include <linux/init.h> |
| #include <linux/sched.h> |
| #include <linux/clkdev.h> |
| |
| #include "clk.h" |
| |
| static DEFINE_SPINLOCK(enable_lock); |
| static DEFINE_MUTEX(prepare_lock); |
| |
| static struct task_struct *prepare_owner; |
| static struct task_struct *enable_owner; |
| |
| static int prepare_refcnt; |
| static int enable_refcnt; |
| |
| static HLIST_HEAD(clk_root_list); |
| static HLIST_HEAD(clk_orphan_list); |
| static LIST_HEAD(clk_notifier_list); |
| |
| /*** private data structures ***/ |
| |
| struct clk_core { |
| const char *name; |
| const struct clk_ops *ops; |
| struct clk_hw *hw; |
| struct module *owner; |
| struct clk_core *parent; |
| const char **parent_names; |
| struct clk_core **parents; |
| u8 num_parents; |
| u8 new_parent_index; |
| unsigned long rate; |
| unsigned long req_rate; |
| unsigned long new_rate; |
| struct clk_core *new_parent; |
| struct clk_core *new_child; |
| unsigned long flags; |
| bool orphan; |
| unsigned int enable_count; |
| unsigned int prepare_count; |
| unsigned long min_rate; |
| unsigned long max_rate; |
| unsigned long accuracy; |
| int phase; |
| struct hlist_head children; |
| struct hlist_node child_node; |
| struct hlist_head clks; |
| unsigned int notifier_count; |
| #ifdef CONFIG_DEBUG_FS |
| struct dentry *dentry; |
| struct hlist_node debug_node; |
| #endif |
| struct kref ref; |
| }; |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/clk.h> |
| |
| struct clk { |
| struct clk_core *core; |
| const char *dev_id; |
| const char *con_id; |
| unsigned long min_rate; |
| unsigned long max_rate; |
| struct hlist_node clks_node; |
| }; |
| |
| /*** 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) |
| __acquires(enable_lock) |
| { |
| unsigned long flags; |
| |
| if (!spin_trylock_irqsave(&enable_lock, flags)) { |
| if (enable_owner == current) { |
| enable_refcnt++; |
| __acquire(enable_lock); |
| 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) |
| __releases(enable_lock) |
| { |
| WARN_ON_ONCE(enable_owner != current); |
| WARN_ON_ONCE(enable_refcnt == 0); |
| |
| if (--enable_refcnt) { |
| __release(enable_lock); |
| return; |
| } |
| enable_owner = NULL; |
| spin_unlock_irqrestore(&enable_lock, flags); |
| } |
| |
| static bool clk_core_is_prepared(struct clk_core *core) |
| { |
| /* |
| * .is_prepared is optional for clocks that can prepare |
| * fall back to software usage counter if it is missing |
| */ |
| if (!core->ops->is_prepared) |
| return core->prepare_count; |
| |
| return core->ops->is_prepared(core->hw); |
| } |
| |
| static bool clk_core_is_enabled(struct clk_core *core) |
| { |
| /* |
| * .is_enabled is only mandatory for clocks that gate |
| * fall back to software usage counter if .is_enabled is missing |
| */ |
| if (!core->ops->is_enabled) |
| return core->enable_count; |
| |
| return core->ops->is_enabled(core->hw); |
| } |
| |
| static void clk_unprepare_unused_subtree(struct clk_core *core) |
| { |
| struct clk_core *child; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| hlist_for_each_entry(child, &core->children, child_node) |
| clk_unprepare_unused_subtree(child); |
| |
| if (core->prepare_count) |
| return; |
| |
| if (core->flags & CLK_IGNORE_UNUSED) |
| return; |
| |
| if (clk_core_is_prepared(core)) { |
| trace_clk_unprepare(core); |
| if (core->ops->unprepare_unused) |
| core->ops->unprepare_unused(core->hw); |
| else if (core->ops->unprepare) |
| core->ops->unprepare(core->hw); |
| trace_clk_unprepare_complete(core); |
| } |
| } |
| |
| static void clk_disable_unused_subtree(struct clk_core *core) |
| { |
| struct clk_core *child; |
| unsigned long flags; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| hlist_for_each_entry(child, &core->children, child_node) |
| clk_disable_unused_subtree(child); |
| |
| flags = clk_enable_lock(); |
| |
| if (core->enable_count) |
| goto unlock_out; |
| |
| if (core->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_core_is_enabled(core)) { |
| trace_clk_disable(core); |
| if (core->ops->disable_unused) |
| core->ops->disable_unused(core->hw); |
| else if (core->ops->disable) |
| core->ops->disable(core->hw); |
| trace_clk_disable_complete(core); |
| } |
| |
| unlock_out: |
| clk_enable_unlock(flags); |
| } |
| |
| 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_core *core; |
| |
| if (clk_ignore_unused) { |
| pr_warn("clk: Not disabling unused clocks\n"); |
| return 0; |
| } |
| |
| clk_prepare_lock(); |
| |
| hlist_for_each_entry(core, &clk_root_list, child_node) |
| clk_disable_unused_subtree(core); |
| |
| hlist_for_each_entry(core, &clk_orphan_list, child_node) |
| clk_disable_unused_subtree(core); |
| |
| hlist_for_each_entry(core, &clk_root_list, child_node) |
| clk_unprepare_unused_subtree(core); |
| |
| hlist_for_each_entry(core, &clk_orphan_list, child_node) |
| clk_unprepare_unused_subtree(core); |
| |
| clk_prepare_unlock(); |
| |
| return 0; |
| } |
| late_initcall_sync(clk_disable_unused); |
| |
| /*** helper functions ***/ |
| |
| const char *__clk_get_name(const struct clk *clk) |
| { |
| return !clk ? NULL : clk->core->name; |
| } |
| EXPORT_SYMBOL_GPL(__clk_get_name); |
| |
| const char *clk_hw_get_name(const struct clk_hw *hw) |
| { |
| return hw->core->name; |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_get_name); |
| |
| struct clk_hw *__clk_get_hw(struct clk *clk) |
| { |
| return !clk ? NULL : clk->core->hw; |
| } |
| EXPORT_SYMBOL_GPL(__clk_get_hw); |
| |
| unsigned int clk_hw_get_num_parents(const struct clk_hw *hw) |
| { |
| return hw->core->num_parents; |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_get_num_parents); |
| |
| struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw) |
| { |
| return hw->core->parent ? hw->core->parent->hw : NULL; |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_get_parent); |
| |
| static struct clk_core *__clk_lookup_subtree(const char *name, |
| struct clk_core *core) |
| { |
| struct clk_core *child; |
| struct clk_core *ret; |
| |
| if (!strcmp(core->name, name)) |
| return core; |
| |
| hlist_for_each_entry(child, &core->children, child_node) { |
| ret = __clk_lookup_subtree(name, child); |
| if (ret) |
| return ret; |
| } |
| |
| return NULL; |
| } |
| |
| static struct clk_core *clk_core_lookup(const char *name) |
| { |
| struct clk_core *root_clk; |
| struct clk_core *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; |
| } |
| |
| static struct clk_core *clk_core_get_parent_by_index(struct clk_core *core, |
| u8 index) |
| { |
| if (!core || index >= core->num_parents) |
| return NULL; |
| |
| if (!core->parents[index]) |
| core->parents[index] = |
| clk_core_lookup(core->parent_names[index]); |
| |
| return core->parents[index]; |
| } |
| |
| struct clk_hw * |
| clk_hw_get_parent_by_index(const struct clk_hw *hw, unsigned int index) |
| { |
| struct clk_core *parent; |
| |
| parent = clk_core_get_parent_by_index(hw->core, index); |
| |
| return !parent ? NULL : parent->hw; |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_get_parent_by_index); |
| |
| unsigned int __clk_get_enable_count(struct clk *clk) |
| { |
| return !clk ? 0 : clk->core->enable_count; |
| } |
| |
| static unsigned long clk_core_get_rate_nolock(struct clk_core *core) |
| { |
| unsigned long ret; |
| |
| if (!core) { |
| ret = 0; |
| goto out; |
| } |
| |
| ret = core->rate; |
| |
| if (core->flags & CLK_IS_ROOT) |
| goto out; |
| |
| if (!core->parent) |
| ret = 0; |
| |
| out: |
| return ret; |
| } |
| |
| unsigned long clk_hw_get_rate(const struct clk_hw *hw) |
| { |
| return clk_core_get_rate_nolock(hw->core); |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_get_rate); |
| |
| static unsigned long __clk_get_accuracy(struct clk_core *core) |
| { |
| if (!core) |
| return 0; |
| |
| return core->accuracy; |
| } |
| |
| unsigned long __clk_get_flags(struct clk *clk) |
| { |
| return !clk ? 0 : clk->core->flags; |
| } |
| EXPORT_SYMBOL_GPL(__clk_get_flags); |
| |
| unsigned long clk_hw_get_flags(const struct clk_hw *hw) |
| { |
| return hw->core->flags; |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_get_flags); |
| |
| bool clk_hw_is_prepared(const struct clk_hw *hw) |
| { |
| return clk_core_is_prepared(hw->core); |
| } |
| |
| bool clk_hw_is_enabled(const struct clk_hw *hw) |
| { |
| return clk_core_is_enabled(hw->core); |
| } |
| |
| bool __clk_is_enabled(struct clk *clk) |
| { |
| if (!clk) |
| return false; |
| |
| return clk_core_is_enabled(clk->core); |
| } |
| EXPORT_SYMBOL_GPL(__clk_is_enabled); |
| |
| static bool mux_is_better_rate(unsigned long rate, unsigned long now, |
| unsigned long best, unsigned long flags) |
| { |
| if (flags & CLK_MUX_ROUND_CLOSEST) |
| return abs(now - rate) < abs(best - rate); |
| |
| return now <= rate && now > best; |
| } |
| |
| static int |
| clk_mux_determine_rate_flags(struct clk_hw *hw, struct clk_rate_request *req, |
| unsigned long flags) |
| { |
| struct clk_core *core = hw->core, *parent, *best_parent = NULL; |
| int i, num_parents, ret; |
| unsigned long best = 0; |
| struct clk_rate_request parent_req = *req; |
| |
| /* if NO_REPARENT flag set, pass through to current parent */ |
| if (core->flags & CLK_SET_RATE_NO_REPARENT) { |
| parent = core->parent; |
| if (core->flags & CLK_SET_RATE_PARENT) { |
| ret = __clk_determine_rate(parent ? parent->hw : NULL, |
| &parent_req); |
| if (ret) |
| return ret; |
| |
| best = parent_req.rate; |
| } else if (parent) { |
| best = clk_core_get_rate_nolock(parent); |
| } else { |
| best = clk_core_get_rate_nolock(core); |
| } |
| |
| goto out; |
| } |
| |
| /* find the parent that can provide the fastest rate <= rate */ |
| num_parents = core->num_parents; |
| for (i = 0; i < num_parents; i++) { |
| parent = clk_core_get_parent_by_index(core, i); |
| if (!parent) |
| continue; |
| |
| if (core->flags & CLK_SET_RATE_PARENT) { |
| parent_req = *req; |
| ret = __clk_determine_rate(parent->hw, &parent_req); |
| if (ret) |
| continue; |
| } else { |
| parent_req.rate = clk_core_get_rate_nolock(parent); |
| } |
| |
| if (mux_is_better_rate(req->rate, parent_req.rate, |
| best, flags)) { |
| best_parent = parent; |
| best = parent_req.rate; |
| } |
| } |
| |
| if (!best_parent) |
| return -EINVAL; |
| |
| out: |
| if (best_parent) |
| req->best_parent_hw = best_parent->hw; |
| req->best_parent_rate = best; |
| req->rate = best; |
| |
| return 0; |
| } |
| |
| struct clk *__clk_lookup(const char *name) |
| { |
| struct clk_core *core = clk_core_lookup(name); |
| |
| return !core ? NULL : core->hw->clk; |
| } |
| |
| static void clk_core_get_boundaries(struct clk_core *core, |
| unsigned long *min_rate, |
| unsigned long *max_rate) |
| { |
| struct clk *clk_user; |
| |
| *min_rate = core->min_rate; |
| *max_rate = core->max_rate; |
| |
| hlist_for_each_entry(clk_user, &core->clks, clks_node) |
| *min_rate = max(*min_rate, clk_user->min_rate); |
| |
| hlist_for_each_entry(clk_user, &core->clks, clks_node) |
| *max_rate = min(*max_rate, clk_user->max_rate); |
| } |
| |
| void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate, |
| unsigned long max_rate) |
| { |
| hw->core->min_rate = min_rate; |
| hw->core->max_rate = max_rate; |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_set_rate_range); |
| |
| /* |
| * 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. |
| */ |
| int __clk_mux_determine_rate(struct clk_hw *hw, |
| struct clk_rate_request *req) |
| { |
| return clk_mux_determine_rate_flags(hw, req, 0); |
| } |
| EXPORT_SYMBOL_GPL(__clk_mux_determine_rate); |
| |
| int __clk_mux_determine_rate_closest(struct clk_hw *hw, |
| struct clk_rate_request *req) |
| { |
| return clk_mux_determine_rate_flags(hw, req, CLK_MUX_ROUND_CLOSEST); |
| } |
| EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest); |
| |
| /*** clk api ***/ |
| |
| static void clk_core_unprepare(struct clk_core *core) |
| { |
| lockdep_assert_held(&prepare_lock); |
| |
| if (!core) |
| return; |
| |
| if (WARN_ON(core->prepare_count == 0)) |
| return; |
| |
| if (--core->prepare_count > 0) |
| return; |
| |
| WARN_ON(core->enable_count > 0); |
| |
| trace_clk_unprepare(core); |
| |
| if (core->ops->unprepare) |
| core->ops->unprepare(core->hw); |
| |
| trace_clk_unprepare_complete(core); |
| clk_core_unprepare(core->parent); |
| } |
| |
| /** |
| * clk_unprepare - undo preparation of a clock source |
| * @clk: the clk being unprepared |
| * |
| * clk_unprepare may sleep, which differentiates it from clk_disable. In a |
| * simple case, clk_unprepare can be used instead of clk_disable to gate a clk |
| * if the operation may sleep. One example is a clk which is accessed over |
| * I2c. In the complex case a clk gate operation may require a fast and a slow |
| * part. It is this reason that clk_unprepare and clk_disable are not mutually |
| * exclusive. In fact clk_disable must be called before clk_unprepare. |
| */ |
| void clk_unprepare(struct clk *clk) |
| { |
| if (IS_ERR_OR_NULL(clk)) |
| return; |
| |
| clk_prepare_lock(); |
| clk_core_unprepare(clk->core); |
| clk_prepare_unlock(); |
| } |
| EXPORT_SYMBOL_GPL(clk_unprepare); |
| |
| static int clk_core_prepare(struct clk_core *core) |
| { |
| int ret = 0; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| if (!core) |
| return 0; |
| |
| if (core->prepare_count == 0) { |
| ret = clk_core_prepare(core->parent); |
| if (ret) |
| return ret; |
| |
| trace_clk_prepare(core); |
| |
| if (core->ops->prepare) |
| ret = core->ops->prepare(core->hw); |
| |
| trace_clk_prepare_complete(core); |
| |
| if (ret) { |
| clk_core_unprepare(core->parent); |
| return ret; |
| } |
| } |
| |
| core->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; |
| |
| if (!clk) |
| return 0; |
| |
| clk_prepare_lock(); |
| ret = clk_core_prepare(clk->core); |
| clk_prepare_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(clk_prepare); |
| |
| static void clk_core_disable(struct clk_core *core) |
| { |
| lockdep_assert_held(&enable_lock); |
| |
| if (!core) |
| return; |
| |
| if (WARN_ON(core->enable_count == 0)) |
| return; |
| |
| if (--core->enable_count > 0) |
| return; |
| |
| trace_clk_disable(core); |
| |
| if (core->ops->disable) |
| core->ops->disable(core->hw); |
| |
| trace_clk_disable_complete(core); |
| |
| clk_core_disable(core->parent); |
| } |
| |
| /** |
| * clk_disable - gate a clock |
| * @clk: the clk being gated |
| * |
| * clk_disable must not sleep, which differentiates it from clk_unprepare. In |
| * a simple case, clk_disable can be used instead of clk_unprepare to gate a |
| * clk if the operation is fast and will never sleep. One example is a |
| * SoC-internal clk which is controlled via simple register writes. In the |
| * complex case a clk gate operation may require a fast and a slow part. It is |
| * this reason that clk_unprepare and clk_disable are not mutually exclusive. |
| * In fact clk_disable must be called before clk_unprepare. |
| */ |
| void clk_disable(struct clk *clk) |
| { |
| unsigned long flags; |
| |
| if (IS_ERR_OR_NULL(clk)) |
| return; |
| |
| flags = clk_enable_lock(); |
| clk_core_disable(clk->core); |
| clk_enable_unlock(flags); |
| } |
| EXPORT_SYMBOL_GPL(clk_disable); |
| |
| static int clk_core_enable(struct clk_core *core) |
| { |
| int ret = 0; |
| |
| lockdep_assert_held(&enable_lock); |
| |
| if (!core) |
| return 0; |
| |
| if (WARN_ON(core->prepare_count == 0)) |
| return -ESHUTDOWN; |
| |
| if (core->enable_count == 0) { |
| ret = clk_core_enable(core->parent); |
| |
| if (ret) |
| return ret; |
| |
| trace_clk_enable(core); |
| |
| if (core->ops->enable) |
| ret = core->ops->enable(core->hw); |
| |
| trace_clk_enable_complete(core); |
| |
| if (ret) { |
| clk_core_disable(core->parent); |
| return ret; |
| } |
| } |
| |
| core->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; |
| |
| if (!clk) |
| return 0; |
| |
| flags = clk_enable_lock(); |
| ret = clk_core_enable(clk->core); |
| clk_enable_unlock(flags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(clk_enable); |
| |
| static int clk_core_round_rate_nolock(struct clk_core *core, |
| struct clk_rate_request *req) |
| { |
| struct clk_core *parent; |
| long rate; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| if (!core) |
| return 0; |
| |
| parent = core->parent; |
| if (parent) { |
| req->best_parent_hw = parent->hw; |
| req->best_parent_rate = parent->rate; |
| } else { |
| req->best_parent_hw = NULL; |
| req->best_parent_rate = 0; |
| } |
| |
| if (core->ops->determine_rate) { |
| return core->ops->determine_rate(core->hw, req); |
| } else if (core->ops->round_rate) { |
| rate = core->ops->round_rate(core->hw, req->rate, |
| &req->best_parent_rate); |
| if (rate < 0) |
| return rate; |
| |
| req->rate = rate; |
| } else if (core->flags & CLK_SET_RATE_PARENT) { |
| return clk_core_round_rate_nolock(parent, req); |
| } else { |
| req->rate = core->rate; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * __clk_determine_rate - get the closest rate actually supported by a clock |
| * @hw: determine the rate of this clock |
| * @rate: target rate |
| * @min_rate: returned rate must be greater than this rate |
| * @max_rate: returned rate must be less than this rate |
| * |
| * Useful for clk_ops such as .set_rate and .determine_rate. |
| */ |
| int __clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req) |
| { |
| if (!hw) { |
| req->rate = 0; |
| return 0; |
| } |
| |
| return clk_core_round_rate_nolock(hw->core, req); |
| } |
| EXPORT_SYMBOL_GPL(__clk_determine_rate); |
| |
| unsigned long clk_hw_round_rate(struct clk_hw *hw, unsigned long rate) |
| { |
| int ret; |
| struct clk_rate_request req; |
| |
| clk_core_get_boundaries(hw->core, &req.min_rate, &req.max_rate); |
| req.rate = rate; |
| |
| ret = clk_core_round_rate_nolock(hw->core, &req); |
| if (ret) |
| return 0; |
| |
| return req.rate; |
| } |
| EXPORT_SYMBOL_GPL(clk_hw_round_rate); |
| |
| /** |
| * clk_round_rate - round the given rate for a clk |
| * @clk: the clk for which we are rounding a rate |
| * @rate: the rate which is to be rounded |
| * |
| * Takes in a rate as input and rounds it to a rate that the clk can actually |
| * use which is then returned. If clk doesn't support round_rate operation |
| * then the parent rate is returned. |
| */ |
| long clk_round_rate(struct clk *clk, unsigned long rate) |
| { |
| struct clk_rate_request req; |
| int ret; |
| |
| if (!clk) |
| return 0; |
| |
| clk_prepare_lock(); |
| |
| clk_core_get_boundaries(clk->core, &req.min_rate, &req.max_rate); |
| req.rate = rate; |
| |
| ret = clk_core_round_rate_nolock(clk->core, &req); |
| clk_prepare_unlock(); |
| |
| if (ret) |
| return ret; |
| |
| return req.rate; |
| } |
| EXPORT_SYMBOL_GPL(clk_round_rate); |
| |
| /** |
| * __clk_notify - call clk notifier chain |
| * @core: 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_core *core, 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.old_rate = old_rate; |
| cnd.new_rate = new_rate; |
| |
| list_for_each_entry(cn, &clk_notifier_list, node) { |
| if (cn->clk->core == core) { |
| cnd.clk = cn->clk; |
| ret = srcu_notifier_call_chain(&cn->notifier_head, msg, |
| &cnd); |
| } |
| } |
| |
| return ret; |
| } |
| |
| /** |
| * __clk_recalc_accuracies |
| * @core: 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 its |
| * parent. |
| */ |
| static void __clk_recalc_accuracies(struct clk_core *core) |
| { |
| unsigned long parent_accuracy = 0; |
| struct clk_core *child; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| if (core->parent) |
| parent_accuracy = core->parent->accuracy; |
| |
| if (core->ops->recalc_accuracy) |
| core->accuracy = core->ops->recalc_accuracy(core->hw, |
| parent_accuracy); |
| else |
| core->accuracy = parent_accuracy; |
| |
| hlist_for_each_entry(child, &core->children, child_node) |
| __clk_recalc_accuracies(child); |
| } |
| |
| static long clk_core_get_accuracy(struct clk_core *core) |
| { |
| unsigned long accuracy; |
| |
| clk_prepare_lock(); |
| if (core && (core->flags & CLK_GET_ACCURACY_NOCACHE)) |
| __clk_recalc_accuracies(core); |
| |
| accuracy = __clk_get_accuracy(core); |
| clk_prepare_unlock(); |
| |
| return accuracy; |
| } |
| |
| /** |
| * 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) |
| { |
| if (!clk) |
| return 0; |
| |
| return clk_core_get_accuracy(clk->core); |
| } |
| EXPORT_SYMBOL_GPL(clk_get_accuracy); |
| |
| static unsigned long clk_recalc(struct clk_core *core, |
| unsigned long parent_rate) |
| { |
| if (core->ops->recalc_rate) |
| return core->ops->recalc_rate(core->hw, parent_rate); |
| return parent_rate; |
| } |
| |
| /** |
| * __clk_recalc_rates |
| * @core: 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. |
| */ |
| static void __clk_recalc_rates(struct clk_core *core, unsigned long msg) |
| { |
| unsigned long old_rate; |
| unsigned long parent_rate = 0; |
| struct clk_core *child; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| old_rate = core->rate; |
| |
| if (core->parent) |
| parent_rate = core->parent->rate; |
| |
| core->rate = clk_recalc(core, parent_rate); |
| |
| /* |
| * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE |
| * & ABORT_RATE_CHANGE notifiers |
| */ |
| if (core->notifier_count && msg) |
| __clk_notify(core, msg, old_rate, core->rate); |
| |
| hlist_for_each_entry(child, &core->children, child_node) |
| __clk_recalc_rates(child, msg); |
| } |
| |
| static unsigned long clk_core_get_rate(struct clk_core *core) |
| { |
| unsigned long rate; |
| |
| clk_prepare_lock(); |
| |
| if (core && (core->flags & CLK_GET_RATE_NOCACHE)) |
| __clk_recalc_rates(core, 0); |
| |
| rate = clk_core_get_rate_nolock(core); |
| clk_prepare_unlock(); |
| |
| return rate; |
| } |
| |
| /** |
| * 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) |
| { |
| if (!clk) |
| return 0; |
| |
| return clk_core_get_rate(clk->core); |
| } |
| EXPORT_SYMBOL_GPL(clk_get_rate); |
| |
| static int clk_fetch_parent_index(struct clk_core *core, |
| struct clk_core *parent) |
| { |
| int i; |
| |
| /* |
| * 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_core_lookup. |
| */ |
| for (i = 0; i < core->num_parents; i++) { |
| if (core->parents[i] == parent) |
| return i; |
| |
| if (core->parents[i]) |
| continue; |
| |
| if (!strcmp(core->parent_names[i], parent->name)) { |
| core->parents[i] = clk_core_lookup(parent->name); |
| return i; |
| } |
| } |
| |
| return -EINVAL; |
| } |
| |
| /* |
| * Update the orphan status of @core and all its children. |
| */ |
| static void clk_core_update_orphan_status(struct clk_core *core, bool is_orphan) |
| { |
| struct clk_core *child; |
| |
| core->orphan = is_orphan; |
| |
| hlist_for_each_entry(child, &core->children, child_node) |
| clk_core_update_orphan_status(child, is_orphan); |
| } |
| |
| static void clk_reparent(struct clk_core *core, struct clk_core *new_parent) |
| { |
| bool was_orphan = core->orphan; |
| |
| hlist_del(&core->child_node); |
| |
| if (new_parent) { |
| bool becomes_orphan = new_parent->orphan; |
| |
| /* avoid duplicate POST_RATE_CHANGE notifications */ |
| if (new_parent->new_child == core) |
| new_parent->new_child = NULL; |
| |
| hlist_add_head(&core->child_node, &new_parent->children); |
| |
| if (was_orphan != becomes_orphan) |
| clk_core_update_orphan_status(core, becomes_orphan); |
| } else { |
| hlist_add_head(&core->child_node, &clk_orphan_list); |
| if (!was_orphan) |
| clk_core_update_orphan_status(core, true); |
| } |
| |
| core->parent = new_parent; |
| } |
| |
| static struct clk_core *__clk_set_parent_before(struct clk_core *core, |
| struct clk_core *parent) |
| { |
| unsigned long flags; |
| struct clk_core *old_parent = core->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 (core->prepare_count) { |
| clk_core_prepare(parent); |
| flags = clk_enable_lock(); |
| clk_core_enable(parent); |
| clk_core_enable(core); |
| clk_enable_unlock(flags); |
| } |
| |
| /* update the clk tree topology */ |
| flags = clk_enable_lock(); |
| clk_reparent(core, parent); |
| clk_enable_unlock(flags); |
| |
| return old_parent; |
| } |
| |
| static void __clk_set_parent_after(struct clk_core *core, |
| struct clk_core *parent, |
| struct clk_core *old_parent) |
| { |
| unsigned long flags; |
| |
| /* |
| * Finish the migration of prepare state and undo the changes done |
| * for preventing a race with clk_enable(). |
| */ |
| if (core->prepare_count) { |
| flags = clk_enable_lock(); |
| clk_core_disable(core); |
| clk_core_disable(old_parent); |
| clk_enable_unlock(flags); |
| clk_core_unprepare(old_parent); |
| } |
| } |
| |
| static int __clk_set_parent(struct clk_core *core, struct clk_core *parent, |
| u8 p_index) |
| { |
| unsigned long flags; |
| int ret = 0; |
| struct clk_core *old_parent; |
| |
| old_parent = __clk_set_parent_before(core, parent); |
| |
| trace_clk_set_parent(core, parent); |
| |
| /* change clock input source */ |
| if (parent && core->ops->set_parent) |
| ret = core->ops->set_parent(core->hw, p_index); |
| |
| trace_clk_set_parent_complete(core, parent); |
| |
| if (ret) { |
| flags = clk_enable_lock(); |
| clk_reparent(core, old_parent); |
| clk_enable_unlock(flags); |
| __clk_set_parent_after(core, old_parent, parent); |
| |
| return ret; |
| } |
| |
| __clk_set_parent_after(core, parent, old_parent); |
| |
| return 0; |
| } |
| |
| /** |
| * __clk_speculate_rates |
| * @core: 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. |
| */ |
| static int __clk_speculate_rates(struct clk_core *core, |
| unsigned long parent_rate) |
| { |
| struct clk_core *child; |
| unsigned long new_rate; |
| int ret = NOTIFY_DONE; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| new_rate = clk_recalc(core, parent_rate); |
| |
| /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */ |
| if (core->notifier_count) |
| ret = __clk_notify(core, PRE_RATE_CHANGE, core->rate, new_rate); |
| |
| if (ret & NOTIFY_STOP_MASK) { |
| pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n", |
| __func__, core->name, ret); |
| goto out; |
| } |
| |
| hlist_for_each_entry(child, &core->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_core *core, unsigned long new_rate, |
| struct clk_core *new_parent, u8 p_index) |
| { |
| struct clk_core *child; |
| |
| core->new_rate = new_rate; |
| core->new_parent = new_parent; |
| core->new_parent_index = p_index; |
| /* include clk in new parent's PRE_RATE_CHANGE notifications */ |
| core->new_child = NULL; |
| if (new_parent && new_parent != core->parent) |
| new_parent->new_child = core; |
| |
| hlist_for_each_entry(child, &core->children, child_node) { |
| child->new_rate = clk_recalc(child, new_rate); |
| clk_calc_subtree(child, child->new_rate, NULL, 0); |
| } |
| } |
| |
| /* |
| * calculate the new rates returning the topmost clock that has to be |
| * changed. |
| */ |
| static struct clk_core *clk_calc_new_rates(struct clk_core *core, |
| unsigned long rate) |
| { |
| struct clk_core *top = core; |
| struct clk_core *old_parent, *parent; |
| unsigned long best_parent_rate = 0; |
| unsigned long new_rate; |
| unsigned long min_rate; |
| unsigned long max_rate; |
| int p_index = 0; |
| long ret; |
| |
| /* sanity */ |
| if (IS_ERR_OR_NULL(core)) |
| return NULL; |
| |
| /* save parent rate, if it exists */ |
| parent = old_parent = core->parent; |
| if (parent) |
| best_parent_rate = parent->rate; |
| |
| clk_core_get_boundaries(core, &min_rate, &max_rate); |
| |
| /* find the closest rate and parent clk/rate */ |
| if (core->ops->determine_rate) { |
| struct clk_rate_request req; |
| |
| req.rate = rate; |
| req.min_rate = min_rate; |
| req.max_rate = max_rate; |
| if (parent) { |
| req.best_parent_hw = parent->hw; |
| req.best_parent_rate = parent->rate; |
| } else { |
| req.best_parent_hw = NULL; |
| req.best_parent_rate = 0; |
| } |
| |
| ret = core->ops->determine_rate(core->hw, &req); |
| if (ret < 0) |
| return NULL; |
| |
| best_parent_rate = req.best_parent_rate; |
| new_rate = req.rate; |
| parent = req.best_parent_hw ? req.best_parent_hw->core : NULL; |
| } else if (core->ops->round_rate) { |
| ret = core->ops->round_rate(core->hw, rate, |
| &best_parent_rate); |
| if (ret < 0) |
| return NULL; |
| |
| new_rate = ret; |
| if (new_rate < min_rate || new_rate > max_rate) |
| return NULL; |
| } else if (!parent || !(core->flags & CLK_SET_RATE_PARENT)) { |
| /* pass-through clock without adjustable parent */ |
| core->new_rate = core->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 && |
| (core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) { |
| pr_debug("%s: %s not gated but wants to reparent\n", |
| __func__, core->name); |
| return NULL; |
| } |
| |
| /* try finding the new parent index */ |
| if (parent && core->num_parents > 1) { |
| p_index = clk_fetch_parent_index(core, parent); |
| if (p_index < 0) { |
| pr_debug("%s: clk %s can not be parent of clk %s\n", |
| __func__, parent->name, core->name); |
| return NULL; |
| } |
| } |
| |
| if ((core->flags & CLK_SET_RATE_PARENT) && parent && |
| best_parent_rate != parent->rate) |
| top = clk_calc_new_rates(parent, best_parent_rate); |
| |
| out: |
| clk_calc_subtree(core, 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_core *clk_propagate_rate_change(struct clk_core *core, |
| unsigned long event) |
| { |
| struct clk_core *child, *tmp_clk, *fail_clk = NULL; |
| int ret = NOTIFY_DONE; |
| |
| if (core->rate == core->new_rate) |
| return NULL; |
| |
| if (core->notifier_count) { |
| ret = __clk_notify(core, event, core->rate, core->new_rate); |
| if (ret & NOTIFY_STOP_MASK) |
| fail_clk = core; |
| } |
| |
| hlist_for_each_entry(child, &core->children, child_node) { |
| /* Skip children who will be reparented to another clock */ |
| if (child->new_parent && child->new_parent != core) |
| 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 core->children yet */ |
| if (core->new_child) { |
| tmp_clk = clk_propagate_rate_change(core->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_core *core) |
| { |
| struct clk_core *child; |
| struct hlist_node *tmp; |
| unsigned long old_rate; |
| unsigned long best_parent_rate = 0; |
| bool skip_set_rate = false; |
| struct clk_core *old_parent; |
| |
| old_rate = core->rate; |
| |
| if (core->new_parent) |
| best_parent_rate = core->new_parent->rate; |
| else if (core->parent) |
| best_parent_rate = core->parent->rate; |
| |
| if (core->flags & CLK_SET_RATE_UNGATE) { |
| unsigned long flags; |
| |
| clk_core_prepare(core); |
| flags = clk_enable_lock(); |
| clk_core_enable(core); |
| clk_enable_unlock(flags); |
| } |
| |
| if (core->new_parent && core->new_parent != core->parent) { |
| old_parent = __clk_set_parent_before(core, core->new_parent); |
| trace_clk_set_parent(core, core->new_parent); |
| |
| if (core->ops->set_rate_and_parent) { |
| skip_set_rate = true; |
| core->ops->set_rate_and_parent(core->hw, core->new_rate, |
| best_parent_rate, |
| core->new_parent_index); |
| } else if (core->ops->set_parent) { |
| core->ops->set_parent(core->hw, core->new_parent_index); |
| } |
| |
| trace_clk_set_parent_complete(core, core->new_parent); |
| __clk_set_parent_after(core, core->new_parent, old_parent); |
| } |
| |
| trace_clk_set_rate(core, core->new_rate); |
| |
| if (!skip_set_rate && core->ops->set_rate) |
| core->ops->set_rate(core->hw, core->new_rate, best_parent_rate); |
| |
| trace_clk_set_rate_complete(core, core->new_rate); |
| |
| core->rate = clk_recalc(core, best_parent_rate); |
| |
| if (core->flags & CLK_SET_RATE_UNGATE) { |
| unsigned long flags; |
| |
| flags = clk_enable_lock(); |
| clk_core_disable(core); |
| clk_enable_unlock(flags); |
| clk_core_unprepare(core); |
| } |
| |
| if (core->notifier_count && old_rate != core->rate) |
| __clk_notify(core, POST_RATE_CHANGE, old_rate, core->rate); |
| |
| if (core->flags & CLK_RECALC_NEW_RATES) |
| (void)clk_calc_new_rates(core, core->new_rate); |
| |
| /* |
| * Use safe iteration, as change_rate can actually swap parents |
| * for certain clock types. |
| */ |
| hlist_for_each_entry_safe(child, tmp, &core->children, child_node) { |
| /* Skip children who will be reparented to another clock */ |
| if (child->new_parent && child->new_parent != core) |
| continue; |
| clk_change_rate(child); |
| } |
| |
| /* handle the new child who might not be in core->children yet */ |
| if (core->new_child) |
| clk_change_rate(core->new_child); |
| } |
| |
| static int clk_core_set_rate_nolock(struct clk_core *core, |
| unsigned long req_rate) |
| { |
| struct clk_core *top, *fail_clk; |
| unsigned long rate = req_rate; |
| int ret = 0; |
| |
| if (!core) |
| return 0; |
| |
| /* bail early if nothing to do */ |
| if (rate == clk_core_get_rate_nolock(core)) |
| return 0; |
| |
| if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count) |
| return -EBUSY; |
| |
| /* calculate new rates and get the topmost changed clock */ |
| top = clk_calc_new_rates(core, rate); |
| if (!top) |
| return -EINVAL; |
| |
| /* notify that we are about to change rates */ |
| fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE); |
| if (fail_clk) { |
| pr_debug("%s: failed to set %s rate\n", __func__, |
| fail_clk->name); |
| clk_propagate_rate_change(top, ABORT_RATE_CHANGE); |
| return -EBUSY; |
| } |
| |
| /* change the rates */ |
| clk_change_rate(top); |
| |
| core->req_rate = req_rate; |
| |
| return ret; |
| } |
| |
| /** |
| * 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) |
| { |
| int ret; |
| |
| if (!clk) |
| return 0; |
| |
| /* prevent racing with updates to the clock topology */ |
| clk_prepare_lock(); |
| |
| ret = clk_core_set_rate_nolock(clk->core, rate); |
| |
| clk_prepare_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(clk_set_rate); |
| |
| /** |
| * clk_set_rate_range - set a rate range for a clock source |
| * @clk: clock source |
| * @min: desired minimum clock rate in Hz, inclusive |
| * @max: desired maximum clock rate in Hz, inclusive |
| * |
| * Returns success (0) or negative errno. |
| */ |
| int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max) |
| { |
| int ret = 0; |
| |
| if (!clk) |
| return 0; |
| |
| if (min > max) { |
| pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n", |
| __func__, clk->core->name, clk->dev_id, clk->con_id, |
| min, max); |
| return -EINVAL; |
| } |
| |
| clk_prepare_lock(); |
| |
| if (min != clk->min_rate || max != clk->max_rate) { |
| clk->min_rate = min; |
| clk->max_rate = max; |
| ret = clk_core_set_rate_nolock(clk->core, clk->core->req_rate); |
| } |
| |
| clk_prepare_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(clk_set_rate_range); |
| |
| /** |
| * clk_set_min_rate - set a minimum clock rate for a clock source |
| * @clk: clock source |
| * @rate: desired minimum clock rate in Hz, inclusive |
| * |
| * Returns success (0) or negative errno. |
| */ |
| int clk_set_min_rate(struct clk *clk, unsigned long rate) |
| { |
| if (!clk) |
| return 0; |
| |
| return clk_set_rate_range(clk, rate, clk->max_rate); |
| } |
| EXPORT_SYMBOL_GPL(clk_set_min_rate); |
| |
| /** |
| * clk_set_max_rate - set a maximum clock rate for a clock source |
| * @clk: clock source |
| * @rate: desired maximum clock rate in Hz, inclusive |
| * |
| * Returns success (0) or negative errno. |
| */ |
| int clk_set_max_rate(struct clk *clk, unsigned long rate) |
| { |
| if (!clk) |
| return 0; |
| |
| return clk_set_rate_range(clk, clk->min_rate, rate); |
| } |
| EXPORT_SYMBOL_GPL(clk_set_max_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; |
| |
| if (!clk) |
| return NULL; |
| |
| clk_prepare_lock(); |
| /* TODO: Create a per-user clk and change callers to call clk_put */ |
| parent = !clk->core->parent ? NULL : clk->core->parent->hw->clk; |
| clk_prepare_unlock(); |
| |
| return parent; |
| } |
| EXPORT_SYMBOL_GPL(clk_get_parent); |
| |
| static struct clk_core *__clk_init_parent(struct clk_core *core) |
| { |
| u8 index = 0; |
| |
| if (core->ops->get_parent) |
| index = core->ops->get_parent(core->hw); |
| |
| return clk_core_get_parent_by_index(core, index); |
| } |
| |
| static void clk_core_reparent(struct clk_core *core, |
| struct clk_core *new_parent) |
| { |
| clk_reparent(core, new_parent); |
| __clk_recalc_accuracies(core); |
| __clk_recalc_rates(core, POST_RATE_CHANGE); |
| } |
| |
| void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent) |
| { |
| if (!hw) |
| return; |
| |
| clk_core_reparent(hw->core, !new_parent ? NULL : new_parent->core); |
| } |
| |
| /** |
| * clk_has_parent - check if a clock is a possible parent for another |
| * @clk: clock source |
| * @parent: parent clock source |
| * |
| * This function can be used in drivers that need to check that a clock can be |
| * the parent of another without actually changing the parent. |
| * |
| * Returns true if @parent is a possible parent for @clk, false otherwise. |
| */ |
| bool clk_has_parent(struct clk *clk, struct clk *parent) |
| { |
| struct clk_core *core, *parent_core; |
| unsigned int i; |
| |
| /* NULL clocks should be nops, so return success if either is NULL. */ |
| if (!clk || !parent) |
| return true; |
| |
| core = clk->core; |
| parent_core = parent->core; |
| |
| /* Optimize for the case where the parent is already the parent. */ |
| if (core->parent == parent_core) |
| return true; |
| |
| for (i = 0; i < core->num_parents; i++) |
| if (strcmp(core->parent_names[i], parent_core->name) == 0) |
| return true; |
| |
| return false; |
| } |
| EXPORT_SYMBOL_GPL(clk_has_parent); |
| |
| static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent) |
| { |
| int ret = 0; |
| int p_index = 0; |
| unsigned long p_rate = 0; |
| |
| if (!core) |
| return 0; |
| |
| /* prevent racing with updates to the clock topology */ |
| clk_prepare_lock(); |
| |
| if (core->parent == parent) |
| goto out; |
| |
| /* verify ops for for multi-parent clks */ |
| if ((core->num_parents > 1) && (!core->ops->set_parent)) { |
| ret = -ENOSYS; |
| goto out; |
| } |
| |
| /* check that we are allowed to re-parent if the clock is in use */ |
| if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) { |
| ret = -EBUSY; |
| goto out; |
| } |
| |
| /* try finding the new parent index */ |
| if (parent) { |
| p_index = clk_fetch_parent_index(core, parent); |
| p_rate = parent->rate; |
| if (p_index < 0) { |
| pr_debug("%s: clk %s can not be parent of clk %s\n", |
| __func__, parent->name, core->name); |
| ret = p_index; |
| goto out; |
| } |
| } |
| |
| /* propagate PRE_RATE_CHANGE notifications */ |
| ret = __clk_speculate_rates(core, p_rate); |
| |
| /* abort if a driver objects */ |
| if (ret & NOTIFY_STOP_MASK) |
| goto out; |
| |
| /* do the re-parent */ |
| ret = __clk_set_parent(core, parent, p_index); |
| |
| /* propagate rate an accuracy recalculation accordingly */ |
| if (ret) { |
| __clk_recalc_rates(core, ABORT_RATE_CHANGE); |
| } else { |
| __clk_recalc_rates(core, POST_RATE_CHANGE); |
| __clk_recalc_accuracies(core); |
| } |
| |
| out: |
| clk_prepare_unlock(); |
| |
| return ret; |
| } |
| |
| /** |
| * 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) |
| { |
| if (!clk) |
| return 0; |
| |
| return clk_core_set_parent(clk->core, parent ? parent->core : NULL); |
| } |
| EXPORT_SYMBOL_GPL(clk_set_parent); |
| |
| /** |
| * clk_set_phase - adjust the phase shift of a clock signal |
| * @clk: clock signal source |
| * @degrees: number of degrees the signal is shifted |
| * |
| * Shifts the phase of a clock signal by the specified |
| * degrees. Returns 0 on success, -EERROR otherwise. |
| * |
| * This function makes no distinction about the input or reference |
| * signal that we adjust the clock signal phase against. For example |
| * phase locked-loop clock signal generators we may shift phase with |
| * respect to feedback clock signal input, but for other cases the |
| * clock phase may be shifted with respect to some other, unspecified |
| * signal. |
| * |
| * Additionally the concept of phase shift does not propagate through |
| * the clock tree hierarchy, which sets it apart from clock rates and |
| * clock accuracy. A parent clock phase attribute does not have an |
| * impact on the phase attribute of a child clock. |
| */ |
| int clk_set_phase(struct clk *clk, int degrees) |
| { |
| int ret = -EINVAL; |
| |
| if (!clk) |
| return 0; |
| |
| /* sanity check degrees */ |
| degrees %= 360; |
| if (degrees < 0) |
| degrees += 360; |
| |
| clk_prepare_lock(); |
| |
| trace_clk_set_phase(clk->core, degrees); |
| |
| if (clk->core->ops->set_phase) |
| ret = clk->core->ops->set_phase(clk->core->hw, degrees); |
| |
| trace_clk_set_phase_complete(clk->core, degrees); |
| |
| if (!ret) |
| clk->core->phase = degrees; |
| |
| clk_prepare_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(clk_set_phase); |
| |
| static int clk_core_get_phase(struct clk_core *core) |
| { |
| int ret; |
| |
| clk_prepare_lock(); |
| ret = core->phase; |
| clk_prepare_unlock(); |
| |
| return ret; |
| } |
| |
| /** |
| * clk_get_phase - return the phase shift of a clock signal |
| * @clk: clock signal source |
| * |
| * Returns the phase shift of a clock node in degrees, otherwise returns |
| * -EERROR. |
| */ |
| int clk_get_phase(struct clk *clk) |
| { |
| if (!clk) |
| return 0; |
| |
| return clk_core_get_phase(clk->core); |
| } |
| EXPORT_SYMBOL_GPL(clk_get_phase); |
| |
| /** |
| * clk_is_match - check if two clk's point to the same hardware clock |
| * @p: clk compared against q |
| * @q: clk compared against p |
| * |
| * Returns true if the two struct clk pointers both point to the same hardware |
| * clock node. Put differently, returns true if struct clk *p and struct clk *q |
| * share the same struct clk_core object. |
| * |
| * Returns false otherwise. Note that two NULL clks are treated as matching. |
| */ |
| bool clk_is_match(const struct clk *p, const struct clk *q) |
| { |
| /* trivial case: identical struct clk's or both NULL */ |
| if (p == q) |
| return true; |
| |
| /* true if clk->core pointers match. Avoid dereferencing garbage */ |
| if (!IS_ERR_OR_NULL(p) && !IS_ERR_OR_NULL(q)) |
| if (p->core == q->core) |
| return true; |
| |
| return false; |
| } |
| EXPORT_SYMBOL_GPL(clk_is_match); |
| |
| /*** debugfs support ***/ |
| |
| #ifdef CONFIG_DEBUG_FS |
| #include <linux/debugfs.h> |
| |
| static struct dentry *rootdir; |
| static int inited = 0; |
| static DEFINE_MUTEX(clk_debug_lock); |
| static HLIST_HEAD(clk_debug_list); |
| |
| static struct hlist_head *all_lists[] = { |
| &clk_root_list, |
| &clk_orphan_list, |
| NULL, |
| }; |
| |
| static struct hlist_head *orphan_list[] = { |
| &clk_orphan_list, |
| NULL, |
| }; |
| |
| static void clk_summary_show_one(struct seq_file *s, struct clk_core *c, |
| int level) |
| { |
| if (!c) |
| return; |
| |
| seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n", |
| level * 3 + 1, "", |
| 30 - level * 3, c->name, |
| c->enable_count, c->prepare_count, clk_core_get_rate(c), |
| clk_core_get_accuracy(c), clk_core_get_phase(c)); |
| } |
| |
| static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c, |
| int level) |
| { |
| struct clk_core *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_core *c; |
| struct hlist_head **lists = (struct hlist_head **)s->private; |
| |
| seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n"); |
| seq_puts(s, "----------------------------------------------------------------------------------------\n"); |
| |
| clk_prepare_lock(); |
| |
| for (; *lists; lists++) |
| hlist_for_each_entry(c, *lists, 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_core *c, int level) |
| { |
| if (!c) |
| return; |
| |
| /* This should be JSON format, i.e. elements separated with a comma */ |
| 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_core_get_rate(c)); |
| seq_printf(s, "\"accuracy\": %lu,", clk_core_get_accuracy(c)); |
| seq_printf(s, "\"phase\": %d", clk_core_get_phase(c)); |
| } |
| |
| static void clk_dump_subtree(struct seq_file *s, struct clk_core *c, int level) |
| { |
| struct clk_core *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_core *c; |
| bool first_node = true; |
| struct hlist_head **lists = (struct hlist_head **)s->private; |
| |
| seq_printf(s, "{"); |
| |
| clk_prepare_lock(); |
| |
| for (; *lists; lists++) { |
| hlist_for_each_entry(c, *lists, child_node) { |
| if (!first_node) |
| seq_puts(s, ","); |
| first_node = false; |
| clk_dump_subtree(s, c, 0); |
| } |
| } |
| |
| clk_prepare_unlock(); |
| |
| seq_puts(s, "}\n"); |
| 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, |
| }; |
| |
| static int clk_debug_create_one(struct clk_core *core, struct dentry *pdentry) |
| { |
| struct dentry *d; |
| int ret = -ENOMEM; |
| |
| if (!core || !pdentry) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| d = debugfs_create_dir(core->name, pdentry); |
| if (!d) |
| goto out; |
| |
| core->dentry = d; |
| |
| d = debugfs_create_u32("clk_rate", S_IRUGO, core->dentry, |
| (u32 *)&core->rate); |
| if (!d) |
| goto err_out; |
| |
| d = debugfs_create_u32("clk_accuracy", S_IRUGO, core->dentry, |
| (u32 *)&core->accuracy); |
| if (!d) |
| goto err_out; |
| |
| d = debugfs_create_u32("clk_phase", S_IRUGO, core->dentry, |
| (u32 *)&core->phase); |
| if (!d) |
| goto err_out; |
| |
| d = debugfs_create_x32("clk_flags", S_IRUGO, core->dentry, |
| (u32 *)&core->flags); |
| if (!d) |
| goto err_out; |
| |
| d = debugfs_create_u32("clk_prepare_count", S_IRUGO, core->dentry, |
| (u32 *)&core->prepare_count); |
| if (!d) |
| goto err_out; |
| |
| d = debugfs_create_u32("clk_enable_count", S_IRUGO, core->dentry, |
| (u32 *)&core->enable_count); |
| if (!d) |
| goto err_out; |
| |
| d = debugfs_create_u32("clk_notifier_count", S_IRUGO, core->dentry, |
| (u32 *)&core->notifier_count); |
| if (!d) |
| goto err_out; |
| |
| if (core->ops->debug_init) { |
| ret = core->ops->debug_init(core->hw, core->dentry); |
| if (ret) |
| goto err_out; |
| } |
| |
| ret = 0; |
| goto out; |
| |
| err_out: |
| debugfs_remove_recursive(core->dentry); |
| core->dentry = NULL; |
| out: |
| return ret; |
| } |
| |
| /** |
| * clk_debug_register - add a clk node to the debugfs clk directory |
| * @core: the clk being added to the debugfs clk directory |
| * |
| * Dynamically adds a clk to the debugfs clk directory if debugfs has been |
| * initialized. Otherwise it bails out early since the debugfs clk directory |
| * will be created lazily by clk_debug_init as part of a late_initcall. |
| */ |
| static int clk_debug_register(struct clk_core *core) |
| { |
| int ret = 0; |
| |
| mutex_lock(&clk_debug_lock); |
| hlist_add_head(&core->debug_node, &clk_debug_list); |
| |
| if (!inited) |
| goto unlock; |
| |
| ret = clk_debug_create_one(core, rootdir); |
| unlock: |
| mutex_unlock(&clk_debug_lock); |
| |
| return ret; |
| } |
| |
| /** |
| * clk_debug_unregister - remove a clk node from the debugfs clk directory |
| * @core: the clk being removed from the debugfs clk directory |
| * |
| * Dynamically removes a clk and all its child nodes from the |
| * debugfs clk directory if clk->dentry points to debugfs created by |
| * clk_debug_register in __clk_init. |
| */ |
| static void clk_debug_unregister(struct clk_core *core) |
| { |
| mutex_lock(&clk_debug_lock); |
| hlist_del_init(&core->debug_node); |
| debugfs_remove_recursive(core->dentry); |
| core->dentry = NULL; |
| mutex_unlock(&clk_debug_lock); |
| } |
| |
| struct dentry *clk_debugfs_add_file(struct clk_hw *hw, char *name, umode_t mode, |
| void *data, const struct file_operations *fops) |
| { |
| struct dentry *d = NULL; |
| |
| if (hw->core->dentry) |
| d = debugfs_create_file(name, mode, hw->core->dentry, data, |
| fops); |
| |
| return d; |
| } |
| EXPORT_SYMBOL_GPL(clk_debugfs_add_file); |
| |
| /** |
| * clk_debug_init - lazily populate the debugfs clk directory |
| * |
| * clks are often initialized very early during boot before memory can be |
| * dynamically allocated and well before debugfs is setup. This function |
| * populates the debugfs clk directory once at boot-time when we know that |
| * debugfs is setup. It should only be called once at boot-time, all other clks |
| * added dynamically will be done so with clk_debug_register. |
| */ |
| static int __init clk_debug_init(void) |
| { |
| struct clk_core *core; |
| struct dentry *d; |
| |
| rootdir = debugfs_create_dir("clk", NULL); |
| |
| if (!rootdir) |
| return -ENOMEM; |
| |
| d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists, |
| &clk_summary_fops); |
| if (!d) |
| return -ENOMEM; |
| |
| d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists, |
| &clk_dump_fops); |
| if (!d) |
| return -ENOMEM; |
| |
| d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir, |
| &orphan_list, &clk_summary_fops); |
| if (!d) |
| return -ENOMEM; |
| |
| d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir, |
| &orphan_list, &clk_dump_fops); |
| if (!d) |
| return -ENOMEM; |
| |
| mutex_lock(&clk_debug_lock); |
| hlist_for_each_entry(core, &clk_debug_list, debug_node) |
| clk_debug_create_one(core, rootdir); |
| |
| inited = 1; |
| mutex_unlock(&clk_debug_lock); |
| |
| return 0; |
| } |
| late_initcall(clk_debug_init); |
| #else |
| static inline int clk_debug_register(struct clk_core *core) { return 0; } |
| static inline void clk_debug_reparent(struct clk_core *core, |
| struct clk_core *new_parent) |
| { |
| } |
| static inline void clk_debug_unregister(struct clk_core *core) |
| { |
| } |
| #endif |
| |
| /** |
| * __clk_is_ancestor - check if a clk_core is a possible ancestor of another |
| * @core: clock core |
| * @ancestor: ancestor clock core |
| * |
| * Returns true if there is a possibility that @ancestor can be an ancestor |
| * of @core, false otherwise. |
| * |
| * This function can be used against @core or @ancestor that has not been |
| * registered yet. |
| */ |
| static bool __clk_is_ancestor(struct clk_core *core, struct clk_core *ancestor) |
| { |
| struct clk_core *parent; |
| int i; |
| |
| for (i = 0; i < core->num_parents; i++) { |
| parent = clk_core_get_parent_by_index(core, i); |
| /* |
| * If ancestor has not been added to clk_{root,orphan}_list |
| * yet, clk_core_lookup() cannot find it. If parent is NULL, |
| * compare the name strings, too. |
| */ |
| if ((parent && (parent == ancestor || |
| __clk_is_ancestor(parent, ancestor))) || |
| (!parent && !strcmp(core->parent_names[i], ancestor->name))) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /** |
| * __clk_core_init - initialize the data structures in a struct clk_core |
| * @core: clk_core being initialized |
| * |
| * Initializes the lists in struct clk_core, queries the hardware for the |
| * parent and rate and sets them both. |
| */ |
| static int __clk_core_init(struct clk_core *core) |
| { |
| int i, ret = 0; |
| struct clk_core *orphan; |
| struct hlist_node *tmp2; |
| unsigned long rate; |
| |
| if (!core) |
| return -EINVAL; |
| |
| clk_prepare_lock(); |
| |
| /* check to see if a clock with this name is already registered */ |
| if (clk_core_lookup(core->name)) { |
| pr_debug("%s: clk %s already initialized\n", |
| __func__, core->name); |
| ret = -EEXIST; |
| goto out; |
| } |
| |
| /* check that clk_ops are sane. See Documentation/clk.txt */ |
| if (core->ops->set_rate && |
| !((core->ops->round_rate || core->ops->determine_rate) && |
| core->ops->recalc_rate)) { |
| pr_err("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n", |
| __func__, core->name); |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (core->ops->set_parent && !core->ops->get_parent) { |
| pr_err("%s: %s must implement .get_parent & .set_parent\n", |
| __func__, core->name); |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (core->num_parents > 1 && !core->ops->get_parent) { |
| pr_err("%s: %s must implement .get_parent as it has multi parents\n", |
| __func__, core->name); |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (core->ops->set_rate_and_parent && |
| !(core->ops->set_parent && core->ops->set_rate)) { |
| pr_err("%s: %s must implement .set_parent & .set_rate\n", |
| __func__, core->name); |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| /* throw a WARN if any entries in parent_names are NULL */ |
| for (i = 0; i < core->num_parents; i++) |
| WARN(!core->parent_names[i], |
| "%s: invalid NULL in %s's .parent_names\n", |
| __func__, core->name); |
| |
| /* If core is an ancestor of itself, it would make a loop. */ |
| if (__clk_is_ancestor(core, core)) { |
| pr_err("%s: %s would create circular parent\n", __func__, |
| core->name); |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| core->parent = __clk_init_parent(core); |
| |
| /* |
| * Populate core->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 (core->parent) { |
| hlist_add_head(&core->child_node, |
| &core->parent->children); |
| core->orphan = core->parent->orphan; |
| } else if (core->flags & CLK_IS_ROOT) { |
| hlist_add_head(&core->child_node, &clk_root_list); |
| core->orphan = false; |
| } else { |
| hlist_add_head(&core->child_node, &clk_orphan_list); |
| core->orphan = true; |
| } |
| |
| /* |
| * 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 (core->ops->recalc_accuracy) |
| core->accuracy = core->ops->recalc_accuracy(core->hw, |
| __clk_get_accuracy(core->parent)); |
| else if (core->parent) |
| core->accuracy = core->parent->accuracy; |
| else |
| core->accuracy = 0; |
| |
| /* |
| * Set clk's phase. |
| * Since a phase is by definition relative to its parent, just |
| * query the current clock phase, or just assume it's in phase. |
| */ |
| if (core->ops->get_phase) |
| core->phase = core->ops->get_phase(core->hw); |
| else |
| core->phase = 0; |
| |
| /* |
| * Set clk's rate. The preferred method is to use .recalc_rate. For |
| * simple clocks and lazy developers the default fallback is to use the |
| * parent's rate. If a clock doesn't have a parent (or is orphaned) |
| * then rate is set to zero. |
| */ |
| if (core->ops->recalc_rate) |
| rate = core->ops->recalc_rate(core->hw, |
| clk_core_get_rate_nolock(core->parent)); |
| else if (core->parent) |
| rate = core->parent->rate; |
| else |
| rate = 0; |
| core->rate = core->req_rate = rate; |
| |
| /* |
| * walk the list of orphan clocks and reparent any that are children of |
| * this clock |
| */ |
| hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { |
| if (orphan->num_parents && orphan->ops->get_parent) { |
| i = orphan->ops->get_parent(orphan->hw); |
| if (i >= 0 && i < orphan->num_parents && |
| !strcmp(core->name, orphan->parent_names[i])) |
| clk_core_reparent(orphan, core); |
| continue; |
| } |
| |
| for (i = 0; i < orphan->num_parents; i++) |
| if (!strcmp(core->name, orphan->parent_names[i])) { |
| clk_core_reparent(orphan, core); |
| 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 (core->ops->init) |
| core->ops->init(core->hw); |
| |
| kref_init(&core->ref); |
| out: |
| clk_prepare_unlock(); |
| |
| if (!ret) |
| clk_debug_register(core); |
| |
| return ret; |
| } |
| |
| struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id, |
| const char *con_id) |
| { |
| struct clk *clk; |
| |
| /* This is to allow this function to be chained to others */ |
| if (IS_ERR_OR_NULL(hw)) |
| return (struct clk *) hw; |
| |
| clk = kzalloc(sizeof(*clk), GFP_KERNEL); |
| if (!clk) |
| return ERR_PTR(-ENOMEM); |
| |
| clk->core = hw->core; |
| clk->dev_id = dev_id; |
| clk->con_id = con_id; |
| clk->max_rate = ULONG_MAX; |
| |
| clk_prepare_lock(); |
| hlist_add_head(&clk->clks_node, &hw->core->clks); |
| clk_prepare_unlock(); |
| |
| return clk; |
| } |
| |
| void __clk_free_clk(struct clk *clk) |
| { |
| clk_prepare_lock(); |
| hlist_del(&clk->clks_node); |
| clk_prepare_unlock(); |
| |
| kfree(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 conjunction 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_core *core; |
| |
| core = kzalloc(sizeof(*core), GFP_KERNEL); |
| if (!core) { |
| ret = -ENOMEM; |
| goto fail_out; |
| } |
| |
| core->name = kstrdup_const(hw->init->name, GFP_KERNEL); |
| if (!core->name) { |
| ret = -ENOMEM; |
| goto fail_name; |
| } |
| core->ops = hw->init->ops; |
| if (dev && dev->driver) |
| core->owner = dev->driver->owner; |
| core->hw = hw; |
| core->flags = hw->init->flags; |
| core->num_parents = hw->init->num_parents; |
| core->min_rate = 0; |
| core->max_rate = ULONG_MAX; |
| hw->core = core; |
| |
| /* allocate local copy in case parent_names is __initdata */ |
| core->parent_names = kcalloc(core->num_parents, sizeof(char *), |
| GFP_KERNEL); |
| |
| if (!core->parent_names) { |
| ret = -ENOMEM; |
| goto fail_parent_names; |
| } |
| |
| |
| /* copy each string name in case parent_names is __initdata */ |
| for (i = 0; i < core->num_parents; i++) { |
| core->parent_names[i] = kstrdup_const(hw->init->parent_names[i], |
| GFP_KERNEL); |
| if (!core->parent_names[i]) { |
| ret = -ENOMEM; |
| goto fail_parent_names_copy; |
| } |
| } |
| |
| /* avoid unnecessary string look-ups of clk_core's possible parents. */ |
| core->parents = kcalloc(core->num_parents, sizeof(*core->parents), |
| GFP_KERNEL); |
| if (!core->parents) { |
| ret = -ENOMEM; |
| goto fail_parents; |
| }; |
| |
| INIT_HLIST_HEAD(&core->clks); |
| |
| hw->clk = __clk_create_clk(hw, NULL, NULL); |
| if (IS_ERR(hw->clk)) { |
| ret = PTR_ERR(hw->clk); |
| goto fail_parents; |
| } |
| |
| ret = __clk_core_init(core); |
| if (!ret) |
| return hw->clk; |
| |
| __clk_free_clk(hw->clk); |
| hw->clk = NULL; |
| |
| fail_parents: |
| kfree(core->parents); |
| fail_parent_names_copy: |
| while (--i >= 0) |
| kfree_const(core->parent_names[i]); |
| kfree(core->parent_names); |
| fail_parent_names: |
| kfree_const(core->name); |
| fail_name: |
| kfree(core); |
| fail_out: |
| return ERR_PTR(ret); |
| } |
| EXPORT_SYMBOL_GPL(clk_register); |
| |
| /* Free memory allocated for a clock. */ |
| static void __clk_release(struct kref *ref) |
| { |
| struct clk_core *core = container_of(ref, struct clk_core, ref); |
| int i = core->num_parents; |
| |
| lockdep_assert_held(&prepare_lock); |
| |
| kfree(core->parents); |
| while (--i >= 0) |
| kfree_const(core->parent_names[i]); |
| |
| kfree(core->parent_names); |
| kfree_const(core->name); |
| kfree(core); |
| } |
| |
| /* |
| * Empty clk_ops for unregistered clocks. These are used temporarily |
| * after clk_unregister() was called on a clock and until last clock |
| * consumer calls clk_put() and the struct clk object is freed. |
| */ |
| static int clk_nodrv_prepare_enable(struct clk_hw *hw) |
| { |
| return -ENXIO; |
| } |
| |
| static void clk_nodrv_disable_unprepare(struct clk_hw *hw) |
| { |
| WARN_ON_ONCE(1); |
| } |
| |
| static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate, |
| unsigned long parent_rate) |
| { |
| return -ENXIO; |
| } |
| |
| static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index) |
| { |
| return -ENXIO; |
| } |
| |
| static const struct clk_ops clk_nodrv_ops = { |
| .enable = clk_nodrv_prepare_enable, |
| .disable = clk_nodrv_disable_unprepare, |
| .prepare = clk_nodrv_prepare_enable, |
| .unprepare = clk_nodrv_disable_unprepare, |
| .set_rate = clk_nodrv_set_rate, |
| .set_parent = clk_nodrv_set_parent, |
| }; |
| |
| /** |
| * clk_unregister - unregister a currently registered clock |
| * @clk: clock to unregister |
| */ |
| void clk_unregister(struct clk *clk) |
| { |
| unsigned long flags; |
| |
| if (!clk || WARN_ON_ONCE(IS_ERR(clk))) |
| return; |
| |
| clk_debug_unregister(clk->core); |
| |
| clk_prepare_lock(); |
| |
| if (clk->core->ops == &clk_nodrv_ops) { |
| pr_err("%s: unregistered clock: %s\n", __func__, |
| clk->core->name); |
| return; |
| } |
| /* |
| * Assign empty clock ops for consumers that might still hold |
| * a reference to this clock. |
| */ |
| flags = clk_enable_lock(); |
| clk->core->ops = &clk_nodrv_ops; |
| clk_enable_unlock(flags); |
| |
| if (!hlist_empty(&clk->core->children)) { |
| struct clk_core *child; |
| struct hlist_node *t; |
| |
| /* Reparent all children to the orphan list. */ |
| hlist_for_each_entry_safe(child, t, &clk->core->children, |
| child_node) |
| clk_core_set_parent(child, NULL); |
| } |
| |
| hlist_del_init(&clk->core->child_node); |
| |
| if (clk->core->prepare_count) |
| pr_warn("%s: unregistering prepared clock: %s\n", |
| __func__, clk->core->name); |
| kref_put(&clk->core->ref, __clk_release); |
| |
| clk_prepare_unlock(); |
| } |
| EXPORT_SYMBOL_GPL(clk_unregister); |
| |
| static void devm_clk_release(struct device *dev, void *res) |
| { |
| clk_unregister(*(struct clk **)res); |
| } |
| |
| /** |
| * devm_clk_register - resource managed clk_register() |
| * @dev: device that is registering this clock |
| * @hw: link to hardware-specific clock data |
| * |
| * Managed clk_register(). Clocks returned from this function are |
| * automatically clk_unregister()ed on driver detach. See clk_register() for |
| * more information. |
| */ |
| struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw) |
| { |
| struct clk *clk; |
| struct clk **clkp; |
| |
| clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL); |
| if (!clkp) |
| return ERR_PTR(-ENOMEM); |
| |
| clk = clk_register(dev, hw); |
| if (!IS_ERR(clk)) { |
| *clkp = clk; |
| devres_add(dev, clkp); |
| } else { |
| devres_free(clkp); |
| } |
| |
| return clk; |
| } |
| EXPORT_SYMBOL_GPL(devm_clk_register); |
| |
| static int devm_clk_match(struct device *dev, void *res, void *data) |
| { |
| struct clk *c = res; |
| if (WARN_ON(!c)) |
| return 0; |
| return c == data; |
| } |
| |
| /** |
| * devm_clk_unregister - resource managed clk_unregister() |
| * @clk: clock to unregister |
| * |
| * Deallocate a clock allocated with devm_clk_register(). Normally |
| * this function will not need to be called and the resource management |
| * code will ensure that the resource is freed. |
| */ |
| void devm_clk_unregister(struct device *dev, struct clk *clk) |
| { |
| WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk)); |
| } |
| EXPORT_SYMBOL_GPL(devm_clk_unregister); |
| |
| /* |
| * clkdev helpers |
| */ |
| int __clk_get(struct clk *clk) |
| { |
| struct clk_core *core = !clk ? NULL : clk->core; |
| |
| if (core) { |
| if (!try_module_get(core->owner)) |
| return 0; |
| |
| kref_get(&core->ref); |
| } |
| return 1; |
| } |
| |
| void __clk_put(struct clk *clk) |
| { |
| struct module *owner; |
| |
| if (!clk || WARN_ON_ONCE(IS_ERR(clk))) |
| return; |
| |
| clk_prepare_lock(); |
| |
| hlist_del(&clk->clks_node); |
| if (clk->min_rate > clk->core->req_rate || |
| clk->max_rate < clk->core->req_rate) |
| clk_core_set_rate_nolock(clk->core, clk->core->req_rate); |
| |
| owner = clk->core->owner; |
| kref_put(&clk->core->ref, __clk_release); |
| |
| clk_prepare_unlock(); |
| |
| module_put(owner); |
| |
| kfree(clk); |
| } |
| |
| /*** clk rate change notifiers ***/ |
| |
| /** |
| * clk_notifier_register - add a clk rate change notifier |
| * @clk: struct clk * to watch |
| * @nb: struct notifier_block * with callback info |
| * |
| * Request notification when clk's rate changes. This uses an SRCU |
| * notifier because we want it to block and notifier unregistrations are |
| * uncommon. The callbacks associated with the notifier must not |
| * re-enter into the clk framework by calling any top-level clk APIs; |
| * this will cause a nested prepare_lock mutex. |
| * |
| * In all notification cases (pre, post and abort rate change) the original |
| * clock rate is passed to the callback via struct clk_notifier_data.old_rate |
| * and the new frequency is passed via struct clk_notifier_data.new_rate. |
| * |
| * clk_notifier_register() must be called from non-atomic context. |
| * Returns -EINVAL if called with null arguments, -ENOMEM upon |
| * allocation failure; otherwise, passes along the return value of |
| * srcu_notifier_chain_register(). |
| */ |
| int clk_notifier_register(struct clk *clk, struct notifier_block *nb) |
| { |
| struct clk_notifier *cn; |
| int ret = -ENOMEM; |
| |
| if (!clk || !nb) |
| return -EINVAL; |
| |
| clk_prepare_lock(); |
| |
| /* search the list of notifiers for this clk */ |
| list_for_each_entry(cn, &clk_notifier_list, node) |
| if (cn->clk == clk) |
| break; |
| |
| /* if clk wasn't in the notifier list, allocate new clk_notifier */ |
| if (cn->clk != clk) { |
| cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL); |
| if (!cn) |
| goto out; |
| |
| cn->clk = clk; |
| srcu_init_notifier_head(&cn->notifier_head); |
| |
| list_add(&cn->node, &clk_notifier_list); |
| } |
| |
| ret = srcu_notifier_chain_register(&cn->notifier_head, nb); |
| |
| clk->core->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->core->notifier_count--; |
| |
| /* XXX the notifier code should handle this better */ |
| if (!cn->notifier_head.head) { |
| srcu_cleanup_notifier_head(&cn->notifier_head); |
| list_del(&cn->node); |
| kfree(cn); |
| } |
| |
| } else { |
| ret = -ENOENT; |
| } |
| |
| clk_prepare_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(clk_notifier_unregister); |
| |
| #ifdef CONFIG_OF |
| /** |
| * struct of_clk_provider - Clock provider registration structure |
| * @link: Entry in global list of clock providers |
| * @node: Pointer to device tree node of clock provider |
| * @get: Get clock callback. Returns NULL or a struct clk for the |
| * given clock specifier |
| * @data: context pointer to be passed into @get callback |
| */ |
| struct of_clk_provider { |
| struct list_head link; |
| |
| struct device_node *node; |
| struct clk *(*get)(struct of_phandle_args *clkspec, void *data); |
| void *data; |
| }; |
| |
| static const struct of_device_id __clk_of_table_sentinel |
| __used __section(__clk_of_table_end); |
| |
| static LIST_HEAD(of_clk_providers); |
| static DEFINE_MUTEX(of_clk_mutex); |
| |
| 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 %u\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; |
| int ret; |
| |
| cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL); |
| if (!cp) |
| return -ENOMEM; |
| |
| cp->node = of_node_get(np); |
| cp->data = data; |
| cp->get = clk_src_get; |
| |
| mutex_lock(&of_clk_mutex); |
| list_add(&cp->link, &of_clk_providers); |
| mutex_unlock(&of_clk_mutex); |
| pr_debug("Added clock from %s\n", np->full_name); |
| |
| ret = of_clk_set_defaults(np, true); |
| if (ret < 0) |
| of_clk_del_provider(np); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(of_clk_add_provider); |
| |
| /** |
| * of_clk_del_provider() - Remove a previously registered clock provider |
| * @np: Device node pointer associated with clock provider |
| */ |
| void of_clk_del_provider(struct device_node *np) |
| { |
| struct of_clk_provider *cp; |
| |
| mutex_lock(&of_clk_mutex); |
| list_for_each_entry(cp, &of_clk_providers, link) { |
| if (cp->node == np) { |
| list_del(&cp->link); |
| of_node_put(cp->node); |
| kfree(cp); |
| break; |
| } |
| } |
| mutex_unlock(&of_clk_mutex); |
| } |
| EXPORT_SYMBOL_GPL(of_clk_del_provider); |
| |
| struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec, |
| const char *dev_id, const char *con_id) |
| { |
| struct of_clk_provider *provider; |
| struct clk *clk = ERR_PTR(-EPROBE_DEFER); |
| |
| if (!clkspec) |
| return ERR_PTR(-EINVAL); |
| |
| /* Check if we have such a provider in our array */ |
| mutex_lock(&of_clk_mutex); |
| list_for_each_entry(provider, &of_clk_providers, link) { |
| if (provider->node == clkspec->np) |
| clk = provider->get(clkspec, provider->data); |
| if (!IS_ERR(clk)) { |
| clk = __clk_create_clk(__clk_get_hw(clk), dev_id, |
| con_id); |
| |
| if (!IS_ERR(clk) && !__clk_get(clk)) { |
| __clk_free_clk(clk); |
| clk = ERR_PTR(-ENOENT); |
| } |
| |
| break; |
| } |
| } |
| mutex_unlock(&of_clk_mutex); |
| |
| return clk; |
| } |
| |
| /** |
| * of_clk_get_from_provider() - Lookup a clock from a clock provider |
| * @clkspec: pointer to a clock specifier data structure |
| * |
| * This function looks up a struct clk from the registered list of clock |
| * providers, an input is a clock specifier data structure as returned |
| * from the of_parse_phandle_with_args() function call. |
| */ |
| struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) |
| { |
| return __of_clk_get_from_provider(clkspec, NULL, __func__); |
| } |
| |
| 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; |
| struct clk *clk; |
| |
| rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, |
| &clkspec); |
| if (rc) |
| return NULL; |
| |
| index = clkspec.args_count ? clkspec.args[0] : 0; |
| count = 0; |
| |
| /* if there is an indices property, use it to transfer the index |
| * specified into an array offset for the clock-output-names property. |
| */ |
| of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) { |
| if (index == pv) { |
| index = count; |
| break; |
| } |
| count++; |
| } |
| /* We went off the end of 'clock-indices' without finding it */ |
| if (prop && !vp) |
| return NULL; |
| |
| if (of_property_read_string_index(clkspec.np, "clock-output-names", |
| index, |
| &clk_name) < 0) { |
| /* |
| * Best effort to get the name if the clock has been |
| * registered with the framework. If the clock isn't |
| * registered, we return the node name as the name of |
| * the clock as long as #clock-cells = 0. |
| */ |
| clk = of_clk_get_from_provider(&clkspec); |
| if (IS_ERR(clk)) { |
| if (clkspec.args_count == 0) |
| clk_name = clkspec.np->name; |
| else |
| clk_name = NULL; |
| } else { |
| clk_name = __clk_get_name(clk); |
| clk_put(clk); |
| } |
| } |
| |
| |
| of_node_put(clkspec.np); |
| return clk_name; |
| } |
| EXPORT_SYMBOL_GPL(of_clk_get_parent_name); |
| |
| /** |
| * of_clk_parent_fill() - Fill @parents with names of @np's parents and return |
| * number of parents |
| * @np: Device node pointer associated with clock provider |
| * @parents: pointer to char array that hold the parents' names |
| * @size: size of the @parents array |
| * |
| * Return: number of parents for the clock node. |
| */ |
| int of_clk_parent_fill(struct device_node *np, const char **parents, |
| unsigned int size) |
| { |
| unsigned int i = 0; |
| |
| while (i < size && (parents[i] = of_clk_get_parent_name(np, i)) != NULL) |
| i++; |
| |
| return i; |
| } |
| EXPORT_SYMBOL_GPL(of_clk_parent_fill); |
| |
| struct clock_provider { |
| of_clk_init_cb_t clk_init_cb; |
| struct device_node *np; |
| struct list_head node; |
| }; |
| |
| /* |
| * This function looks for a parent clock. If there is one, then it |
| * checks that the provider for this parent clock was initialized, in |
| * this case the parent clock will be ready. |
| */ |
| static int parent_ready(struct device_node *np) |
| { |
| int i = 0; |
| |
| while (true) { |
| struct clk *clk = of_clk_get(np, i); |
| |
| /* this parent is ready we can check the next one */ |
| if (!IS_ERR(clk)) { |
| clk_put(clk); |
| i++; |
| continue; |
| } |
| |
| /* at least one parent is not ready, we exit now */ |
| if (PTR_ERR(clk) == -EPROBE_DEFER) |
| return 0; |
| |
| /* |
| * Here we make assumption that the device tree is |
| * written correctly. So an error means that there is |
| * no more parent. As we didn't exit yet, then the |
| * previous parent are ready. If there is no clock |
| * parent, no need to wait for them, then we can |
| * consider their absence as being ready |
| */ |
| return 1; |
| } |
| } |
| |
| /** |
| * of_clk_init() - Scan and init clock providers from the DT |
| * @matches: array of compatible values and init functions for providers. |
| * |
| * This function scans the device tree for matching clock providers |
| * and calls their initialization functions. It also does it by trying |
| * to follow the dependencies. |
| */ |
| void __init of_clk_init(const struct of_device_id *matches) |
| { |
| const struct of_device_id *match; |
| struct device_node *np; |
| struct clock_provider *clk_provider, *next; |
| bool is_init_done; |
| bool force = false; |
| LIST_HEAD(clk_provider_list); |
| |
| if (!matches) |
| matches = &__clk_of_table; |
| |
| /* First prepare the list of the clocks providers */ |
| for_each_matching_node_and_match(np, matches, &match) { |
| struct clock_provider *parent; |
| |
| parent = kzalloc(sizeof(*parent), GFP_KERNEL); |
| if (!parent) { |
| list_for_each_entry_safe(clk_provider, next, |
| &clk_provider_list, node) { |
| list_del(&clk_provider->node); |
| of_node_put(clk_provider->np); |
| kfree(clk_provider); |
| } |
| of_node_put(np); |
| return; |
| } |
| |
| parent->clk_init_cb = match->data; |
| parent->np = of_node_get(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); |
| of_clk_set_defaults(clk_provider->np, true); |
| |
| list_del(&clk_provider->node); |
| of_node_put(clk_provider->np); |
| kfree(clk_provider); |
| is_init_done = true; |
| } |
| } |
| |
| /* |
| * We didn't manage to initialize any of the |
| * remaining providers during the last loop, so now we |
| * initialize all the remaining ones unconditionally |
| * in case the clock parent was not mandatory |
| */ |
| if (!is_init_done) |
| force = true; |
| } |
| } |
| #endif |