| /* |
| * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> |
| * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * Standard functionality for the common clock API. See Documentation/clk.txt |
| */ |
| |
| #include <linux/clk-private.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/spinlock.h> |
| #include <linux/err.h> |
| #include <linux/list.h> |
| #include <linux/slab.h> |
| #include <linux/of.h> |
| #include <linux/device.h> |
| #include <linux/init.h> |
| #include <linux/sched.h> |
| |
| #if defined(CONFIG_COMMON_CLK) |
| |
| 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 <linux/debugfs.h> |
| |
| static struct dentry *rootdir; |
| static struct dentry *orphandir; |
| static int inited = 0; |
| |
| static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level) |
| { |
| if (!c) |
| return; |
| |
| seq_printf(s, "%*s%-*s %-11d %-12d %-10lu", |
| level * 3 + 1, "", |
| 30 - level * 3, c->name, |
| c->enable_count, c->prepare_count, c->rate); |
| 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", c->rate); |
| } |
| |
| 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(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; |
| } |
| |
| 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; |
| } |
| |
| /*** 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 unprepare |
| * |
| * 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 |
| * |
| * 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; |
| |
| if (!clk) |
| return 0; |
| |
| if (!clk->ops->round_rate) { |
| if (clk->flags & CLK_SET_RATE_PARENT) |
| return __clk_round_rate(clk->parent, rate); |
| else |
| return clk->rate; |
| } |
| |
| if (clk->parent) |
| parent_rate = clk->parent->rate; |
| |
| return clk->ops->round_rate(clk->hw, rate, &parent_rate); |
| } |
| |
| /** |
| * 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 it's 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); |
| |
| /** |
| * __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 it's 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 *child; |
| |
| clk->new_rate = new_rate; |
| |
| 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); |
| } |
| } |
| |
| /* |
| * 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; |
| unsigned long best_parent_rate = 0; |
| unsigned long new_rate; |
| |
| /* sanity */ |
| if (IS_ERR_OR_NULL(clk)) |
| return NULL; |
| |
| /* save parent rate, if it exists */ |
| if (clk->parent) |
| best_parent_rate = clk->parent->rate; |
| |
| /* never propagate up to the parent */ |
| if (!(clk->flags & CLK_SET_RATE_PARENT)) { |
| if (!clk->ops->round_rate) { |
| clk->new_rate = clk->rate; |
| return NULL; |
| } |
| new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); |
| goto out; |
| } |
| |
| /* need clk->parent from here on out */ |
| if (!clk->parent) { |
| pr_debug("%s: %s has NULL parent\n", __func__, clk->name); |
| return NULL; |
| } |
| |
| if (!clk->ops->round_rate) { |
| top = clk_calc_new_rates(clk->parent, rate); |
| new_rate = clk->parent->new_rate; |
| |
| goto out; |
| } |
| |
| new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); |
| |
| if (best_parent_rate != clk->parent->rate) { |
| top = clk_calc_new_rates(clk->parent, best_parent_rate); |
| |
| goto out; |
| } |
| |
| out: |
| clk_calc_subtree(clk, new_rate); |
| |
| 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, *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) { |
| clk = clk_propagate_rate_change(child, event); |
| if (clk) |
| fail_clk = 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; |
| |
| 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) |
| clk_change_rate(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 it's 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; |
| |
| /* prevent racing with updates to the clock topology */ |
| clk_prepare_lock(); |
| |
| /* bail early if nothing to do */ |
| if (rate == clk->rate) |
| 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); |
| |
| if (!clk->parents) |
| ret = __clk_lookup(clk->parent_names[index]); |
| else if (!clk->parents[index]) |
| ret = clk->parents[index] = |
| __clk_lookup(clk->parent_names[index]); |
| else |
| ret = clk->parents[index]; |
| |
| out: |
| return ret; |
| } |
| |
| static void clk_reparent(struct clk *clk, struct clk *new_parent) |
| { |
| hlist_del(&clk->child_node); |
| |
| if (new_parent) |
| hlist_add_head(&clk->child_node, &new_parent->children); |
| else |
| hlist_add_head(&clk->child_node, &clk_orphan_list); |
| |
| clk->parent = new_parent; |
| } |
| |
| void __clk_reparent(struct clk *clk, struct clk *new_parent) |
| { |
| clk_reparent(clk, new_parent); |
| clk_debug_reparent(clk, new_parent); |
| __clk_recalc_rates(clk, POST_RATE_CHANGE); |
| } |
| |
| static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent) |
| { |
| u8 i; |
| |
| if (!clk->parents) |
| clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), |
| GFP_KERNEL); |
| |
| /* |
| * find index of new parent clock using cached parent ptrs, |
| * or if not yet cached, use string name comparison and cache |
| * them now to avoid future calls to __clk_lookup. |
| */ |
| for (i = 0; i < clk->num_parents; i++) { |
| if (clk->parents && clk->parents[i] == parent) |
| break; |
| else if (!strcmp(clk->parent_names[i], parent->name)) { |
| if (clk->parents) |
| clk->parents[i] = __clk_lookup(parent->name); |
| break; |
| } |
| } |
| |
| return i; |
| } |
| |
| static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index) |
| { |
| unsigned long flags; |
| int ret = 0; |
| struct clk *old_parent = clk->parent; |
| bool migrated_enable = false; |
| |
| /* migrate prepare */ |
| if (clk->prepare_count) |
| __clk_prepare(parent); |
| |
| flags = clk_enable_lock(); |
| |
| /* migrate enable */ |
| if (clk->enable_count) { |
| __clk_enable(parent); |
| migrated_enable = true; |
| } |
| |
| /* update the clk tree topology */ |
| clk_reparent(clk, parent); |
| |
| clk_enable_unlock(flags); |
| |
| /* change clock input source */ |
| if (parent && clk->ops->set_parent) |
| ret = clk->ops->set_parent(clk->hw, p_index); |
| |
| if (ret) { |
| /* |
| * The error handling is tricky due to that we need to release |
| * the spinlock while issuing the .set_parent callback. This |
| * means the new parent might have been enabled/disabled in |
| * between, which must be considered when doing rollback. |
| */ |
| flags = clk_enable_lock(); |
| |
| clk_reparent(clk, old_parent); |
| |
| if (migrated_enable && clk->enable_count) { |
| __clk_disable(parent); |
| } else if (migrated_enable && (clk->enable_count == 0)) { |
| __clk_disable(old_parent); |
| } else if (!migrated_enable && clk->enable_count) { |
| __clk_disable(parent); |
| __clk_enable(old_parent); |
| } |
| |
| clk_enable_unlock(flags); |
| |
| if (clk->prepare_count) |
| __clk_unprepare(parent); |
| |
| return ret; |
| } |
| |
| /* clean up enable for old parent if migration was done */ |
| if (migrated_enable) { |
| flags = clk_enable_lock(); |
| __clk_disable(old_parent); |
| clk_enable_unlock(flags); |
| } |
| |
| /* clean up prepare for old parent if migration was done */ |
| if (clk->prepare_count) |
| __clk_unprepare(old_parent); |
| |
| /* update debugfs with new clk tree topology */ |
| clk_debug_reparent(clk, parent); |
| return 0; |
| } |
| |
| /** |
| * clk_set_parent - switch the parent of a mux clk |
| * @clk: the mux clk whose input we are switching |
| * @parent: the new input to clk |
| * |
| * Re-parent clk to use parent as it's new input source. If clk has the |
| * CLK_SET_PARENT_GATE flag set then clk must be gated for this |
| * operation to succeed. After successfully changing clk's parent |
| * clk_set_parent will update the clk topology, sysfs topology and |
| * propagate rate recalculation via __clk_recalc_rates. Returns 0 on |
| * success, -EERROR otherwise. |
| */ |
| int clk_set_parent(struct clk *clk, struct clk *parent) |
| { |
| int ret = 0; |
| u8 p_index = 0; |
| unsigned long p_rate = 0; |
| |
| if (!clk || !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 */ |
| if (clk->notifier_count) |
| 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->recalc_rate)) { |
| pr_warning("%s: %s must implement .round_rate & .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 it's 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 it's 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); |
| |
| #endif /* CONFIG_COMMON_CLK */ |
| |
| #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); |
| |
| #if defined(CONFIG_COMMON_CLK) |
| |
| 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); |
| |
| #endif /* CONFIG_COMMON_CLK */ |
| |
| /** |
| * 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); |
| |
| #if defined(CONFIG_COMMON_CLK) |
| |
| /** |
| * 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) |
| { |
| struct device_node *np; |
| |
| if (!matches) |
| matches = __clk_of_table; |
| |
| for_each_matching_node(np, matches) { |
| const struct of_device_id *match = of_match_node(matches, np); |
| of_clk_init_cb_t clk_init_cb = match->data; |
| clk_init_cb(np); |
| } |
| } |
| |
| #endif /* CONFIG_COMMON_CLK */ |
| |
| #endif |