Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1341 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c
new file mode 100644
index 000000000..dedd47e30
--- /dev/null
+++ b/arch/arm/mach-omap2/clockdomain.c
@@ -0,0 +1,1341 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP2/3/4 clockdomain framework functions
+ *
+ * Copyright (C) 2008-2011 Texas Instruments, Inc.
+ * Copyright (C) 2008-2011 Nokia Corporation
+ *
+ * Written by Paul Walmsley and Jouni Högander
+ * Added OMAP4 specific support by Abhijit Pagare <abhijitpagare@ti.com>
+ */
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/limits.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+#include <linux/cpu_pm.h>
+
+#include <linux/io.h>
+
+#include <linux/bitops.h>
+
+#include "soc.h"
+#include "clock.h"
+#include "clockdomain.h"
+#include "pm.h"
+
+/* clkdm_list contains all registered struct clockdomains */
+static LIST_HEAD(clkdm_list);
+
+/* array of clockdomain deps to be added/removed when clkdm in hwsup mode */
+static struct clkdm_autodep *autodeps;
+
+static struct clkdm_ops *arch_clkdm;
+void clkdm_save_context(void);
+void clkdm_restore_context(void);
+
+/* Private functions */
+
+static struct clockdomain *_clkdm_lookup(const char *name)
+{
+	struct clockdomain *clkdm, *temp_clkdm;
+
+	if (!name)
+		return NULL;
+
+	clkdm = NULL;
+
+	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
+		if (!strcmp(name, temp_clkdm->name)) {
+			clkdm = temp_clkdm;
+			break;
+		}
+	}
+
+	return clkdm;
+}
+
+/**
+ * _clkdm_register - register a clockdomain
+ * @clkdm: struct clockdomain * to register
+ *
+ * Adds a clockdomain to the internal clockdomain list.
+ * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
+ * already registered by the provided name, or 0 upon success.
+ */
+static int _clkdm_register(struct clockdomain *clkdm)
+{
+	struct powerdomain *pwrdm;
+
+	if (!clkdm || !clkdm->name)
+		return -EINVAL;
+
+	pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
+	if (!pwrdm) {
+		pr_err("clockdomain: %s: powerdomain %s does not exist\n",
+			clkdm->name, clkdm->pwrdm.name);
+		return -EINVAL;
+	}
+	clkdm->pwrdm.ptr = pwrdm;
+
+	/* Verify that the clockdomain is not already registered */
+	if (_clkdm_lookup(clkdm->name))
+		return -EEXIST;
+
+	list_add(&clkdm->node, &clkdm_list);
+
+	pwrdm_add_clkdm(pwrdm, clkdm);
+
+	pr_debug("clockdomain: registered %s\n", clkdm->name);
+
+	return 0;
+}
+
+/* _clkdm_deps_lookup - look up the specified clockdomain in a clkdm list */
+static struct clkdm_dep *_clkdm_deps_lookup(struct clockdomain *clkdm,
+					    struct clkdm_dep *deps)
+{
+	struct clkdm_dep *cd;
+
+	if (!clkdm || !deps)
+		return ERR_PTR(-EINVAL);
+
+	for (cd = deps; cd->clkdm_name; cd++) {
+		if (!cd->clkdm && cd->clkdm_name)
+			cd->clkdm = _clkdm_lookup(cd->clkdm_name);
+
+		if (cd->clkdm == clkdm)
+			break;
+	}
+
+	if (!cd->clkdm_name)
+		return ERR_PTR(-ENOENT);
+
+	return cd;
+}
+
+/**
+ * _autodep_lookup - resolve autodep clkdm names to clkdm pointers; store
+ * @autodep: struct clkdm_autodep * to resolve
+ *
+ * Resolve autodep clockdomain names to clockdomain pointers via
+ * clkdm_lookup() and store the pointers in the autodep structure.  An
+ * "autodep" is a clockdomain sleep/wakeup dependency that is
+ * automatically added and removed whenever clocks in the associated
+ * clockdomain are enabled or disabled (respectively) when the
+ * clockdomain is in hardware-supervised mode.	Meant to be called
+ * once at clockdomain layer initialization, since these should remain
+ * fixed for a particular architecture.  No return value.
+ *
+ * XXX autodeps are deprecated and should be removed at the earliest
+ * opportunity
+ */
+static void _autodep_lookup(struct clkdm_autodep *autodep)
+{
+	struct clockdomain *clkdm;
+
+	if (!autodep)
+		return;
+
+	clkdm = clkdm_lookup(autodep->clkdm.name);
+	if (!clkdm) {
+		pr_err("clockdomain: autodeps: clockdomain %s does not exist\n",
+			 autodep->clkdm.name);
+		clkdm = ERR_PTR(-ENOENT);
+	}
+	autodep->clkdm.ptr = clkdm;
+}
+
+/**
+ * _resolve_clkdm_deps() - resolve clkdm_names in @clkdm_deps to clkdms
+ * @clkdm: clockdomain that we are resolving dependencies for
+ * @clkdm_deps: ptr to array of struct clkdm_deps to resolve
+ *
+ * Iterates through @clkdm_deps, looking up the struct clockdomain named by
+ * clkdm_name and storing the clockdomain pointer in the struct clkdm_dep.
+ * No return value.
+ */
+static void _resolve_clkdm_deps(struct clockdomain *clkdm,
+				struct clkdm_dep *clkdm_deps)
+{
+	struct clkdm_dep *cd;
+
+	for (cd = clkdm_deps; cd && cd->clkdm_name; cd++) {
+		if (cd->clkdm)
+			continue;
+		cd->clkdm = _clkdm_lookup(cd->clkdm_name);
+
+		WARN(!cd->clkdm, "clockdomain: %s: could not find clkdm %s while resolving dependencies - should never happen",
+		     clkdm->name, cd->clkdm_name);
+	}
+}
+
+/**
+ * _clkdm_add_wkdep - add a wakeup dependency from clkdm2 to clkdm1 (lockless)
+ * @clkdm1: wake this struct clockdomain * up (dependent)
+ * @clkdm2: when this struct clockdomain * wakes up (source)
+ *
+ * When the clockdomain represented by @clkdm2 wakes up, wake up
+ * @clkdm1. Implemented in hardware on the OMAP, this feature is
+ * designed to reduce wakeup latency of the dependent clockdomain @clkdm1.
+ * Returns -EINVAL if presented with invalid clockdomain pointers,
+ * -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or 0 upon
+ * success.
+ */
+static int _clkdm_add_wkdep(struct clockdomain *clkdm1,
+			    struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret = 0;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
+	if (IS_ERR(cd))
+		ret = PTR_ERR(cd);
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_add_wkdep)
+		ret = -EINVAL;
+
+	if (ret) {
+		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
+			 clkdm1->name, clkdm2->name);
+		return ret;
+	}
+
+	cd->wkdep_usecount++;
+	if (cd->wkdep_usecount == 1) {
+		pr_debug("clockdomain: hardware will wake up %s when %s wakes up\n",
+			 clkdm1->name, clkdm2->name);
+
+		ret = arch_clkdm->clkdm_add_wkdep(clkdm1, clkdm2);
+	}
+
+	return ret;
+}
+
+/**
+ * _clkdm_del_wkdep - remove a wakeup dep from clkdm2 to clkdm1 (lockless)
+ * @clkdm1: wake this struct clockdomain * up (dependent)
+ * @clkdm2: when this struct clockdomain * wakes up (source)
+ *
+ * Remove a wakeup dependency causing @clkdm1 to wake up when @clkdm2
+ * wakes up.  Returns -EINVAL if presented with invalid clockdomain
+ * pointers, -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or
+ * 0 upon success.
+ */
+static int _clkdm_del_wkdep(struct clockdomain *clkdm1,
+			    struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret = 0;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
+	if (IS_ERR(cd))
+		ret = PTR_ERR(cd);
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_del_wkdep)
+		ret = -EINVAL;
+
+	if (ret) {
+		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
+			 clkdm1->name, clkdm2->name);
+		return ret;
+	}
+
+	cd->wkdep_usecount--;
+	if (cd->wkdep_usecount == 0) {
+		pr_debug("clockdomain: hardware will no longer wake up %s after %s wakes up\n",
+			 clkdm1->name, clkdm2->name);
+
+		ret = arch_clkdm->clkdm_del_wkdep(clkdm1, clkdm2);
+	}
+
+	return ret;
+}
+
+/**
+ * _clkdm_add_sleepdep - add a sleep dependency from clkdm2 to clkdm1 (lockless)
+ * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
+ * @clkdm2: when this struct clockdomain * is active (source)
+ *
+ * Prevent @clkdm1 from automatically going inactive (and then to
+ * retention or off) if @clkdm2 is active.  Returns -EINVAL if
+ * presented with invalid clockdomain pointers or called on a machine
+ * that does not support software-configurable hardware sleep
+ * dependencies, -ENOENT if the specified dependency cannot be set in
+ * hardware, or 0 upon success.
+ */
+static int _clkdm_add_sleepdep(struct clockdomain *clkdm1,
+			       struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret = 0;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
+	if (IS_ERR(cd))
+		ret = PTR_ERR(cd);
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_add_sleepdep)
+		ret = -EINVAL;
+
+	if (ret) {
+		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
+			 clkdm1->name, clkdm2->name);
+		return ret;
+	}
+
+	cd->sleepdep_usecount++;
+	if (cd->sleepdep_usecount == 1) {
+		pr_debug("clockdomain: will prevent %s from sleeping if %s is active\n",
+			 clkdm1->name, clkdm2->name);
+
+		ret = arch_clkdm->clkdm_add_sleepdep(clkdm1, clkdm2);
+	}
+
+	return ret;
+}
+
+/**
+ * _clkdm_del_sleepdep - remove a sleep dep from clkdm2 to clkdm1 (lockless)
+ * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
+ * @clkdm2: when this struct clockdomain * is active (source)
+ *
+ * Allow @clkdm1 to automatically go inactive (and then to retention or
+ * off), independent of the activity state of @clkdm2.  Returns -EINVAL
+ * if presented with invalid clockdomain pointers or called on a machine
+ * that does not support software-configurable hardware sleep dependencies,
+ * -ENOENT if the specified dependency cannot be cleared in hardware, or
+ * 0 upon success.
+ */
+static int _clkdm_del_sleepdep(struct clockdomain *clkdm1,
+			       struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret = 0;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
+	if (IS_ERR(cd))
+		ret = PTR_ERR(cd);
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_del_sleepdep)
+		ret = -EINVAL;
+
+	if (ret) {
+		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
+			 clkdm1->name, clkdm2->name);
+		return ret;
+	}
+
+	cd->sleepdep_usecount--;
+	if (cd->sleepdep_usecount == 0) {
+		pr_debug("clockdomain: will no longer prevent %s from sleeping if %s is active\n",
+			 clkdm1->name, clkdm2->name);
+
+		ret = arch_clkdm->clkdm_del_sleepdep(clkdm1, clkdm2);
+	}
+
+	return ret;
+}
+
+/* Public functions */
+
+/**
+ * clkdm_register_platform_funcs - register clockdomain implementation fns
+ * @co: func pointers for arch specific implementations
+ *
+ * Register the list of function pointers used to implement the
+ * clockdomain functions on different OMAP SoCs.  Should be called
+ * before any other clkdm_register*() function.  Returns -EINVAL if
+ * @co is null, -EEXIST if platform functions have already been
+ * registered, or 0 upon success.
+ */
+int clkdm_register_platform_funcs(struct clkdm_ops *co)
+{
+	if (!co)
+		return -EINVAL;
+
+	if (arch_clkdm)
+		return -EEXIST;
+
+	arch_clkdm = co;
+
+	return 0;
+};
+
+/**
+ * clkdm_register_clkdms - register SoC clockdomains
+ * @cs: pointer to an array of struct clockdomain to register
+ *
+ * Register the clockdomains available on a particular OMAP SoC.  Must
+ * be called after clkdm_register_platform_funcs().  May be called
+ * multiple times.  Returns -EACCES if called before
+ * clkdm_register_platform_funcs(); -EINVAL if the argument @cs is
+ * null; or 0 upon success.
+ */
+int clkdm_register_clkdms(struct clockdomain **cs)
+{
+	struct clockdomain **c = NULL;
+
+	if (!arch_clkdm)
+		return -EACCES;
+
+	if (!cs)
+		return -EINVAL;
+
+	for (c = cs; *c; c++)
+		_clkdm_register(*c);
+
+	return 0;
+}
+
+/**
+ * clkdm_register_autodeps - register autodeps (if required)
+ * @ia: pointer to a static array of struct clkdm_autodep to register
+ *
+ * Register clockdomain "automatic dependencies."  These are
+ * clockdomain wakeup and sleep dependencies that are automatically
+ * added whenever the first clock inside a clockdomain is enabled, and
+ * removed whenever the last clock inside a clockdomain is disabled.
+ * These are currently only used on OMAP3 devices, and are deprecated,
+ * since they waste energy.  However, until the OMAP2/3 IP block
+ * enable/disable sequence can be converted to match the OMAP4
+ * sequence, they are needed.
+ *
+ * Must be called only after all of the SoC clockdomains are
+ * registered, since the function will resolve autodep clockdomain
+ * names into clockdomain pointers.
+ *
+ * The struct clkdm_autodep @ia array must be static, as this function
+ * does not copy the array elements.
+ *
+ * Returns -EACCES if called before any clockdomains have been
+ * registered, -EINVAL if called with a null @ia argument, -EEXIST if
+ * autodeps have already been registered, or 0 upon success.
+ */
+int clkdm_register_autodeps(struct clkdm_autodep *ia)
+{
+	struct clkdm_autodep *a = NULL;
+
+	if (list_empty(&clkdm_list))
+		return -EACCES;
+
+	if (!ia)
+		return -EINVAL;
+
+	if (autodeps)
+		return -EEXIST;
+
+	autodeps = ia;
+	for (a = autodeps; a->clkdm.ptr; a++)
+		_autodep_lookup(a);
+
+	return 0;
+}
+
+static int cpu_notifier(struct notifier_block *nb, unsigned long cmd, void *v)
+{
+	switch (cmd) {
+	case CPU_CLUSTER_PM_ENTER:
+		if (enable_off_mode)
+			clkdm_save_context();
+		break;
+	case CPU_CLUSTER_PM_EXIT:
+		if (enable_off_mode)
+			clkdm_restore_context();
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+/**
+ * clkdm_complete_init - set up the clockdomain layer
+ *
+ * Put all clockdomains into software-supervised mode; PM code should
+ * later enable hardware-supervised mode as appropriate.  Must be
+ * called after clkdm_register_clkdms().  Returns -EACCES if called
+ * before clkdm_register_clkdms(), or 0 upon success.
+ */
+int clkdm_complete_init(void)
+{
+	struct clockdomain *clkdm;
+	static struct notifier_block nb;
+
+	if (list_empty(&clkdm_list))
+		return -EACCES;
+
+	list_for_each_entry(clkdm, &clkdm_list, node) {
+		clkdm_deny_idle(clkdm);
+
+		_resolve_clkdm_deps(clkdm, clkdm->wkdep_srcs);
+		clkdm_clear_all_wkdeps(clkdm);
+
+		_resolve_clkdm_deps(clkdm, clkdm->sleepdep_srcs);
+		clkdm_clear_all_sleepdeps(clkdm);
+	}
+
+	/* Only AM43XX can lose clkdm context during rtc-ddr suspend */
+	if (soc_is_am43xx()) {
+		nb.notifier_call = cpu_notifier;
+		cpu_pm_register_notifier(&nb);
+	}
+
+	return 0;
+}
+
+/**
+ * clkdm_lookup - look up a clockdomain by name, return a pointer
+ * @name: name of clockdomain
+ *
+ * Find a registered clockdomain by its name @name.  Returns a pointer
+ * to the struct clockdomain if found, or NULL otherwise.
+ */
+struct clockdomain *clkdm_lookup(const char *name)
+{
+	struct clockdomain *clkdm, *temp_clkdm;
+
+	if (!name)
+		return NULL;
+
+	clkdm = NULL;
+
+	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
+		if (!strcmp(name, temp_clkdm->name)) {
+			clkdm = temp_clkdm;
+			break;
+		}
+	}
+
+	return clkdm;
+}
+
+/**
+ * clkdm_for_each - call function on each registered clockdomain
+ * @fn: callback function *
+ *
+ * Call the supplied function @fn for each registered clockdomain.
+ * The callback function @fn can return anything but 0 to bail
+ * out early from the iterator.  The callback function is called with
+ * the clkdm_mutex held, so no clockdomain structure manipulation
+ * functions should be called from the callback, although hardware
+ * clockdomain control functions are fine.  Returns the last return
+ * value of the callback function, which should be 0 for success or
+ * anything else to indicate failure; or -EINVAL if the function pointer
+ * is null.
+ */
+int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
+			void *user)
+{
+	struct clockdomain *clkdm;
+	int ret = 0;
+
+	if (!fn)
+		return -EINVAL;
+
+	list_for_each_entry(clkdm, &clkdm_list, node) {
+		ret = (*fn)(clkdm, user);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+
+/**
+ * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
+ * @clkdm: struct clockdomain *
+ *
+ * Return a pointer to the struct powerdomain that the specified clockdomain
+ * @clkdm exists in, or returns NULL if @clkdm is NULL.
+ */
+struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
+{
+	if (!clkdm)
+		return NULL;
+
+	return clkdm->pwrdm.ptr;
+}
+
+
+/* Hardware clockdomain control */
+
+/**
+ * clkdm_add_wkdep - add a wakeup dependency from clkdm2 to clkdm1
+ * @clkdm1: wake this struct clockdomain * up (dependent)
+ * @clkdm2: when this struct clockdomain * wakes up (source)
+ *
+ * When the clockdomain represented by @clkdm2 wakes up, wake up
+ * @clkdm1. Implemented in hardware on the OMAP, this feature is
+ * designed to reduce wakeup latency of the dependent clockdomain @clkdm1.
+ * Returns -EINVAL if presented with invalid clockdomain pointers,
+ * -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or 0 upon
+ * success.
+ */
+int clkdm_add_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
+	if (IS_ERR(cd))
+		return PTR_ERR(cd);
+
+	pwrdm_lock(cd->clkdm->pwrdm.ptr);
+	ret = _clkdm_add_wkdep(clkdm1, clkdm2);
+	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_del_wkdep - remove a wakeup dependency from clkdm2 to clkdm1
+ * @clkdm1: wake this struct clockdomain * up (dependent)
+ * @clkdm2: when this struct clockdomain * wakes up (source)
+ *
+ * Remove a wakeup dependency causing @clkdm1 to wake up when @clkdm2
+ * wakes up.  Returns -EINVAL if presented with invalid clockdomain
+ * pointers, -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or
+ * 0 upon success.
+ */
+int clkdm_del_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
+	if (IS_ERR(cd))
+		return PTR_ERR(cd);
+
+	pwrdm_lock(cd->clkdm->pwrdm.ptr);
+	ret = _clkdm_del_wkdep(clkdm1, clkdm2);
+	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_read_wkdep - read wakeup dependency state from clkdm2 to clkdm1
+ * @clkdm1: wake this struct clockdomain * up (dependent)
+ * @clkdm2: when this struct clockdomain * wakes up (source)
+ *
+ * Return 1 if a hardware wakeup dependency exists wherein @clkdm1 will be
+ * awoken when @clkdm2 wakes up; 0 if dependency is not set; -EINVAL
+ * if either clockdomain pointer is invalid; or -ENOENT if the hardware
+ * is incapable.
+ *
+ * REVISIT: Currently this function only represents software-controllable
+ * wakeup dependencies.  Wakeup dependencies fixed in hardware are not
+ * yet handled here.
+ */
+int clkdm_read_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret = 0;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
+	if (IS_ERR(cd))
+		ret = PTR_ERR(cd);
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_read_wkdep)
+		ret = -EINVAL;
+
+	if (ret) {
+		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
+			 clkdm1->name, clkdm2->name);
+		return ret;
+	}
+
+	/* XXX It's faster to return the wkdep_usecount */
+	return arch_clkdm->clkdm_read_wkdep(clkdm1, clkdm2);
+}
+
+/**
+ * clkdm_clear_all_wkdeps - remove all wakeup dependencies from target clkdm
+ * @clkdm: struct clockdomain * to remove all wakeup dependencies from
+ *
+ * Remove all inter-clockdomain wakeup dependencies that could cause
+ * @clkdm to wake.  Intended to be used during boot to initialize the
+ * PRCM to a known state, after all clockdomains are put into swsup idle
+ * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
+ * 0 upon success.
+ */
+int clkdm_clear_all_wkdeps(struct clockdomain *clkdm)
+{
+	if (!clkdm)
+		return -EINVAL;
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_wkdeps)
+		return -EINVAL;
+
+	return arch_clkdm->clkdm_clear_all_wkdeps(clkdm);
+}
+
+/**
+ * clkdm_add_sleepdep - add a sleep dependency from clkdm2 to clkdm1
+ * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
+ * @clkdm2: when this struct clockdomain * is active (source)
+ *
+ * Prevent @clkdm1 from automatically going inactive (and then to
+ * retention or off) if @clkdm2 is active.  Returns -EINVAL if
+ * presented with invalid clockdomain pointers or called on a machine
+ * that does not support software-configurable hardware sleep
+ * dependencies, -ENOENT if the specified dependency cannot be set in
+ * hardware, or 0 upon success.
+ */
+int clkdm_add_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
+	if (IS_ERR(cd))
+		return PTR_ERR(cd);
+
+	pwrdm_lock(cd->clkdm->pwrdm.ptr);
+	ret = _clkdm_add_sleepdep(clkdm1, clkdm2);
+	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_del_sleepdep - remove a sleep dependency from clkdm2 to clkdm1
+ * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
+ * @clkdm2: when this struct clockdomain * is active (source)
+ *
+ * Allow @clkdm1 to automatically go inactive (and then to retention or
+ * off), independent of the activity state of @clkdm2.  Returns -EINVAL
+ * if presented with invalid clockdomain pointers or called on a machine
+ * that does not support software-configurable hardware sleep dependencies,
+ * -ENOENT if the specified dependency cannot be cleared in hardware, or
+ * 0 upon success.
+ */
+int clkdm_del_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
+	if (IS_ERR(cd))
+		return PTR_ERR(cd);
+
+	pwrdm_lock(cd->clkdm->pwrdm.ptr);
+	ret = _clkdm_del_sleepdep(clkdm1, clkdm2);
+	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_read_sleepdep - read sleep dependency state from clkdm2 to clkdm1
+ * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
+ * @clkdm2: when this struct clockdomain * is active (source)
+ *
+ * Return 1 if a hardware sleep dependency exists wherein @clkdm1 will
+ * not be allowed to automatically go inactive if @clkdm2 is active;
+ * 0 if @clkdm1's automatic power state inactivity transition is independent
+ * of @clkdm2's; -EINVAL if either clockdomain pointer is invalid or called
+ * on a machine that does not support software-configurable hardware sleep
+ * dependencies; or -ENOENT if the hardware is incapable.
+ *
+ * REVISIT: Currently this function only represents software-controllable
+ * sleep dependencies.	Sleep dependencies fixed in hardware are not
+ * yet handled here.
+ */
+int clkdm_read_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
+{
+	struct clkdm_dep *cd;
+	int ret = 0;
+
+	if (!clkdm1 || !clkdm2)
+		return -EINVAL;
+
+	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
+	if (IS_ERR(cd))
+		ret = PTR_ERR(cd);
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_read_sleepdep)
+		ret = -EINVAL;
+
+	if (ret) {
+		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
+			 clkdm1->name, clkdm2->name);
+		return ret;
+	}
+
+	/* XXX It's faster to return the sleepdep_usecount */
+	return arch_clkdm->clkdm_read_sleepdep(clkdm1, clkdm2);
+}
+
+/**
+ * clkdm_clear_all_sleepdeps - remove all sleep dependencies from target clkdm
+ * @clkdm: struct clockdomain * to remove all sleep dependencies from
+ *
+ * Remove all inter-clockdomain sleep dependencies that could prevent
+ * @clkdm from idling.  Intended to be used during boot to initialize the
+ * PRCM to a known state, after all clockdomains are put into swsup idle
+ * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
+ * 0 upon success.
+ */
+int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
+{
+	if (!clkdm)
+		return -EINVAL;
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_sleepdeps)
+		return -EINVAL;
+
+	return arch_clkdm->clkdm_clear_all_sleepdeps(clkdm);
+}
+
+/**
+ * clkdm_sleep_nolock - force clockdomain sleep transition (lockless)
+ * @clkdm: struct clockdomain *
+ *
+ * Instruct the CM to force a sleep transition on the specified
+ * clockdomain @clkdm.  Only for use by the powerdomain code.  Returns
+ * -EINVAL if @clkdm is NULL or if clockdomain does not support
+ * software-initiated sleep; 0 upon success.
+ */
+int clkdm_sleep_nolock(struct clockdomain *clkdm)
+{
+	int ret;
+
+	if (!clkdm)
+		return -EINVAL;
+
+	if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
+		pr_debug("clockdomain: %s does not support forcing sleep via software\n",
+			 clkdm->name);
+		return -EINVAL;
+	}
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_sleep)
+		return -EINVAL;
+
+	pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
+
+	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
+	ret = arch_clkdm->clkdm_sleep(clkdm);
+	ret |= pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_sleep - force clockdomain sleep transition
+ * @clkdm: struct clockdomain *
+ *
+ * Instruct the CM to force a sleep transition on the specified
+ * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if
+ * clockdomain does not support software-initiated sleep; 0 upon
+ * success.
+ */
+int clkdm_sleep(struct clockdomain *clkdm)
+{
+	int ret;
+
+	pwrdm_lock(clkdm->pwrdm.ptr);
+	ret = clkdm_sleep_nolock(clkdm);
+	pwrdm_unlock(clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_wakeup_nolock - force clockdomain wakeup transition (lockless)
+ * @clkdm: struct clockdomain *
+ *
+ * Instruct the CM to force a wakeup transition on the specified
+ * clockdomain @clkdm.  Only for use by the powerdomain code.  Returns
+ * -EINVAL if @clkdm is NULL or if the clockdomain does not support
+ * software-controlled wakeup; 0 upon success.
+ */
+int clkdm_wakeup_nolock(struct clockdomain *clkdm)
+{
+	int ret;
+
+	if (!clkdm)
+		return -EINVAL;
+
+	if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
+		pr_debug("clockdomain: %s does not support forcing wakeup via software\n",
+			 clkdm->name);
+		return -EINVAL;
+	}
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_wakeup)
+		return -EINVAL;
+
+	pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
+
+	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
+	ret = arch_clkdm->clkdm_wakeup(clkdm);
+	ret |= pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_wakeup - force clockdomain wakeup transition
+ * @clkdm: struct clockdomain *
+ *
+ * Instruct the CM to force a wakeup transition on the specified
+ * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if the
+ * clockdomain does not support software-controlled wakeup; 0 upon
+ * success.
+ */
+int clkdm_wakeup(struct clockdomain *clkdm)
+{
+	int ret;
+
+	pwrdm_lock(clkdm->pwrdm.ptr);
+	ret = clkdm_wakeup_nolock(clkdm);
+	pwrdm_unlock(clkdm->pwrdm.ptr);
+
+	return ret;
+}
+
+/**
+ * clkdm_allow_idle_nolock - enable hwsup idle transitions for clkdm
+ * @clkdm: struct clockdomain *
+ *
+ * Allow the hardware to automatically switch the clockdomain @clkdm
+ * into active or idle states, as needed by downstream clocks.  If the
+ * clockdomain has any downstream clocks enabled in the clock
+ * framework, wkdep/sleepdep autodependencies are added; this is so
+ * device drivers can read and write to the device.  Only for use by
+ * the powerdomain code.  No return value.
+ */
+void clkdm_allow_idle_nolock(struct clockdomain *clkdm)
+{
+	if (!clkdm)
+		return;
+
+	if (!WARN_ON(!clkdm->forcewake_count))
+		clkdm->forcewake_count--;
+
+	if (clkdm->forcewake_count)
+		return;
+
+	if (!clkdm->usecount && (clkdm->flags & CLKDM_CAN_FORCE_SLEEP))
+		clkdm_sleep_nolock(clkdm);
+
+	if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO))
+		return;
+
+	if (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING)
+		return;
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_allow_idle)
+		return;
+
+	pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
+		 clkdm->name);
+
+	clkdm->_flags |= _CLKDM_FLAG_HWSUP_ENABLED;
+	arch_clkdm->clkdm_allow_idle(clkdm);
+	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
+}
+
+/**
+ * clkdm_allow_idle - enable hwsup idle transitions for clkdm
+ * @clkdm: struct clockdomain *
+ *
+ * Allow the hardware to automatically switch the clockdomain @clkdm into
+ * active or idle states, as needed by downstream clocks.  If the
+ * clockdomain has any downstream clocks enabled in the clock
+ * framework, wkdep/sleepdep autodependencies are added; this is so
+ * device drivers can read and write to the device.  No return value.
+ */
+void clkdm_allow_idle(struct clockdomain *clkdm)
+{
+	pwrdm_lock(clkdm->pwrdm.ptr);
+	clkdm_allow_idle_nolock(clkdm);
+	pwrdm_unlock(clkdm->pwrdm.ptr);
+}
+
+/**
+ * clkdm_deny_idle - disable hwsup idle transitions for clkdm
+ * @clkdm: struct clockdomain *
+ *
+ * Prevent the hardware from automatically switching the clockdomain
+ * @clkdm into inactive or idle states.  If the clockdomain has
+ * downstream clocks enabled in the clock framework, wkdep/sleepdep
+ * autodependencies are removed.  Only for use by the powerdomain
+ * code.  No return value.
+ */
+void clkdm_deny_idle_nolock(struct clockdomain *clkdm)
+{
+	if (!clkdm)
+		return;
+
+	if (clkdm->forcewake_count++)
+		return;
+
+	if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
+		clkdm_wakeup_nolock(clkdm);
+
+	if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO))
+		return;
+
+	if (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING)
+		return;
+
+	if (!arch_clkdm || !arch_clkdm->clkdm_deny_idle)
+		return;
+
+	pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
+		 clkdm->name);
+
+	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
+	arch_clkdm->clkdm_deny_idle(clkdm);
+	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
+}
+
+/**
+ * clkdm_deny_idle - disable hwsup idle transitions for clkdm
+ * @clkdm: struct clockdomain *
+ *
+ * Prevent the hardware from automatically switching the clockdomain
+ * @clkdm into inactive or idle states.  If the clockdomain has
+ * downstream clocks enabled in the clock framework, wkdep/sleepdep
+ * autodependencies are removed.  No return value.
+ */
+void clkdm_deny_idle(struct clockdomain *clkdm)
+{
+	pwrdm_lock(clkdm->pwrdm.ptr);
+	clkdm_deny_idle_nolock(clkdm);
+	pwrdm_unlock(clkdm->pwrdm.ptr);
+}
+
+/**
+ * clkdm_in_hwsup - is clockdomain @clkdm have hardware-supervised idle enabled?
+ * @clkdm: struct clockdomain *
+ *
+ * Returns true if clockdomain @clkdm currently has
+ * hardware-supervised idle enabled, or false if it does not or if
+ * @clkdm is NULL.  It is only valid to call this function after
+ * clkdm_init() has been called.  This function does not actually read
+ * bits from the hardware; it instead tests an in-memory flag that is
+ * changed whenever the clockdomain code changes the auto-idle mode.
+ */
+bool clkdm_in_hwsup(struct clockdomain *clkdm)
+{
+	bool ret;
+
+	if (!clkdm)
+		return false;
+
+	ret = (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
+
+	return ret;
+}
+
+/**
+ * clkdm_missing_idle_reporting - can @clkdm enter autoidle even if in use?
+ * @clkdm: struct clockdomain *
+ *
+ * Returns true if clockdomain @clkdm has the
+ * CLKDM_MISSING_IDLE_REPORTING flag set, or false if not or @clkdm is
+ * null.  More information is available in the documentation for the
+ * CLKDM_MISSING_IDLE_REPORTING macro.
+ */
+bool clkdm_missing_idle_reporting(struct clockdomain *clkdm)
+{
+	if (!clkdm)
+		return false;
+
+	return (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING) ? true : false;
+}
+
+/* Public autodep handling functions (deprecated) */
+
+/**
+ * clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
+ * @clkdm: struct clockdomain *
+ *
+ * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
+ * in hardware-supervised mode.  Meant to be called from clock framework
+ * when a clock inside clockdomain 'clkdm' is enabled.	No return value.
+ *
+ * XXX autodeps are deprecated and should be removed at the earliest
+ * opportunity
+ */
+void clkdm_add_autodeps(struct clockdomain *clkdm)
+{
+	struct clkdm_autodep *autodep;
+
+	if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
+		return;
+
+	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
+		if (IS_ERR(autodep->clkdm.ptr))
+			continue;
+
+		pr_debug("clockdomain: %s: adding %s sleepdep/wkdep\n",
+			 clkdm->name, autodep->clkdm.ptr->name);
+
+		_clkdm_add_sleepdep(clkdm, autodep->clkdm.ptr);
+		_clkdm_add_wkdep(clkdm, autodep->clkdm.ptr);
+	}
+}
+
+/**
+ * clkdm_del_autodeps - remove auto sleepdeps/wkdeps from clkdm
+ * @clkdm: struct clockdomain *
+ *
+ * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
+ * in hardware-supervised mode.  Meant to be called from clock framework
+ * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
+ *
+ * XXX autodeps are deprecated and should be removed at the earliest
+ * opportunity
+ */
+void clkdm_del_autodeps(struct clockdomain *clkdm)
+{
+	struct clkdm_autodep *autodep;
+
+	if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
+		return;
+
+	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
+		if (IS_ERR(autodep->clkdm.ptr))
+			continue;
+
+		pr_debug("clockdomain: %s: removing %s sleepdep/wkdep\n",
+			 clkdm->name, autodep->clkdm.ptr->name);
+
+		_clkdm_del_sleepdep(clkdm, autodep->clkdm.ptr);
+		_clkdm_del_wkdep(clkdm, autodep->clkdm.ptr);
+	}
+}
+
+/* Clockdomain-to-clock/hwmod framework interface code */
+
+/**
+ * clkdm_clk_enable - add an enabled downstream clock to this clkdm
+ * @clkdm: struct clockdomain *
+ * @clk: struct clk * of the enabled downstream clock
+ *
+ * Increment the usecount of the clockdomain @clkdm and ensure that it
+ * is awake before @clk is enabled.  Intended to be called by
+ * clk_enable() code.  If the clockdomain is in software-supervised
+ * idle mode, force the clockdomain to wake.  If the clockdomain is in
+ * hardware-supervised idle mode, add clkdm-pwrdm autodependencies, to
+ * ensure that devices in the clockdomain can be read from/written to
+ * by on-chip processors.  Returns -EINVAL if passed null pointers;
+ * returns 0 upon success or if the clockdomain is in hwsup idle mode.
+ */
+int clkdm_clk_enable(struct clockdomain *clkdm, struct clk *unused)
+{
+	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable)
+		return -EINVAL;
+
+	pwrdm_lock(clkdm->pwrdm.ptr);
+
+	/*
+	 * For arch's with no autodeps, clkcm_clk_enable
+	 * should be called for every clock instance or hwmod that is
+	 * enabled, so the clkdm can be force woken up.
+	 */
+	clkdm->usecount++;
+	if (clkdm->usecount > 1 && autodeps) {
+		pwrdm_unlock(clkdm->pwrdm.ptr);
+		return 0;
+	}
+
+	arch_clkdm->clkdm_clk_enable(clkdm);
+	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
+	pwrdm_unlock(clkdm->pwrdm.ptr);
+
+	pr_debug("clockdomain: %s: enabled\n", clkdm->name);
+
+	return 0;
+}
+
+/**
+ * clkdm_clk_disable - remove an enabled downstream clock from this clkdm
+ * @clkdm: struct clockdomain *
+ * @clk: struct clk * of the disabled downstream clock
+ *
+ * Decrement the usecount of this clockdomain @clkdm when @clk is
+ * disabled.  Intended to be called by clk_disable() code.  If the
+ * clockdomain usecount goes to 0, put the clockdomain to sleep
+ * (software-supervised mode) or remove the clkdm autodependencies
+ * (hardware-supervised mode).  Returns -EINVAL if passed null
+ * pointers; -ERANGE if the @clkdm usecount underflows; or returns 0
+ * upon success or if the clockdomain is in hwsup idle mode.
+ */
+int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
+{
+	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
+		return -EINVAL;
+
+	pwrdm_lock(clkdm->pwrdm.ptr);
+
+	/* corner case: disabling unused clocks */
+	if (clk && (__clk_get_enable_count(clk) == 0) && clkdm->usecount == 0)
+		goto ccd_exit;
+
+	if (clkdm->usecount == 0) {
+		pwrdm_unlock(clkdm->pwrdm.ptr);
+		WARN_ON(1); /* underflow */
+		return -ERANGE;
+	}
+
+	clkdm->usecount--;
+	if (clkdm->usecount > 0) {
+		pwrdm_unlock(clkdm->pwrdm.ptr);
+		return 0;
+	}
+
+	arch_clkdm->clkdm_clk_disable(clkdm);
+	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
+
+	pr_debug("clockdomain: %s: disabled\n", clkdm->name);
+
+ccd_exit:
+	pwrdm_unlock(clkdm->pwrdm.ptr);
+
+	return 0;
+}
+
+/**
+ * clkdm_hwmod_enable - add an enabled downstream hwmod to this clkdm
+ * @clkdm: struct clockdomain *
+ * @oh: struct omap_hwmod * of the enabled downstream hwmod
+ *
+ * Increment the usecount of the clockdomain @clkdm and ensure that it
+ * is awake before @oh is enabled. Intended to be called by
+ * module_enable() code.
+ * If the clockdomain is in software-supervised idle mode, force the
+ * clockdomain to wake.  If the clockdomain is in hardware-supervised idle
+ * mode, add clkdm-pwrdm autodependencies, to ensure that devices in the
+ * clockdomain can be read from/written to by on-chip processors.
+ * Returns -EINVAL if passed null pointers;
+ * returns 0 upon success or if the clockdomain is in hwsup idle mode.
+ */
+int clkdm_hwmod_enable(struct clockdomain *clkdm, struct omap_hwmod *oh)
+{
+	/* The clkdm attribute does not exist yet prior OMAP4 */
+	if (cpu_is_omap24xx() || cpu_is_omap34xx())
+		return 0;
+
+	/*
+	 * XXX Rewrite this code to maintain a list of enabled
+	 * downstream hwmods for debugging purposes?
+	 */
+
+	if (!oh)
+		return -EINVAL;
+
+	return clkdm_clk_enable(clkdm, NULL);
+}
+
+/**
+ * clkdm_hwmod_disable - remove an enabled downstream hwmod from this clkdm
+ * @clkdm: struct clockdomain *
+ * @oh: struct omap_hwmod * of the disabled downstream hwmod
+ *
+ * Decrement the usecount of this clockdomain @clkdm when @oh is
+ * disabled. Intended to be called by module_disable() code.
+ * If the clockdomain usecount goes to 0, put the clockdomain to sleep
+ * (software-supervised mode) or remove the clkdm autodependencies
+ * (hardware-supervised mode).
+ * Returns -EINVAL if passed null pointers; -ERANGE if the @clkdm usecount
+ * underflows; or returns 0 upon success or if the clockdomain is in hwsup
+ * idle mode.
+ */
+int clkdm_hwmod_disable(struct clockdomain *clkdm, struct omap_hwmod *oh)
+{
+	/* The clkdm attribute does not exist yet prior OMAP4 */
+	if (cpu_is_omap24xx() || cpu_is_omap34xx())
+		return 0;
+
+	if (!oh)
+		return -EINVAL;
+
+	return clkdm_clk_disable(clkdm, NULL);
+}
+
+/**
+ * _clkdm_save_context - save the context for the control of this clkdm
+ *
+ * Due to a suspend or hibernation operation, the state of the registers
+ * controlling this clkdm will be lost, save their context.
+ */
+static int _clkdm_save_context(struct clockdomain *clkdm, void *ununsed)
+{
+	if (!arch_clkdm || !arch_clkdm->clkdm_save_context)
+		return -EINVAL;
+
+	return arch_clkdm->clkdm_save_context(clkdm);
+}
+
+/**
+ * _clkdm_restore_context - restore context for control of this clkdm
+ *
+ * Restore the register values for this clockdomain.
+ */
+static int _clkdm_restore_context(struct clockdomain *clkdm, void *ununsed)
+{
+	if (!arch_clkdm || !arch_clkdm->clkdm_restore_context)
+		return -EINVAL;
+
+	return arch_clkdm->clkdm_restore_context(clkdm);
+}
+
+/**
+ * clkdm_save_context - Saves the context for each registered clkdm
+ *
+ * Save the context for each registered clockdomain.
+ */
+void clkdm_save_context(void)
+{
+	clkdm_for_each(_clkdm_save_context, NULL);
+}
+
+/**
+ * clkdm_restore_context - Restores the context for each registered clkdm
+ *
+ * Restore the context for each registered clockdomain.
+ */
+void clkdm_restore_context(void)
+{
+	clkdm_for_each(_clkdm_restore_context, NULL);
+}