clk: Add Suspend/Resume Callbacks in Clock

Currently the CCF doesnt have any interface with the system when it goes into suspend state. This patch, on similar lines of syscore, adds clk_suspend/clk_resume functions before system enters suspend state Also there are suspend/resume hooks added for the clock driver

Acked-by Olivier Bideau <[email protected]>

Acked-by Patrice Chotard <[email protected]>

Signed-off-by Pankaj Dev <[email protected]>

---
  drivers/clk/clk.c            |  194 ++++++++++++++++++++++++++++++++++++++++++
  include/linux/clk-provider.h |   21 +++++
  include/linux/clk.h          |   23 +++++
  kernel/kexec.c               |    6 ++
  kernel/power/hibernate.c     |   16 ++++
  kernel/power/suspend.c       |    7 ++
  6 files changed, 267 insertions(+), 0 deletions(-)

drivers/clk/clk.c +194 -0

index 237f23f..3e3b1d7 100644
@@ -2811,6 +2811,200 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
  }
  EXPORT_SYMBOL_GPL(clk_notifier_unregister);
 
+#ifdef CONFIG_PM_SLEEP
+int __clk_resume(struct clk_core *clk)
+{
+	int ret = 0;
+	u8 p_index;
+	unsigned long rate, parent_rate = 0;
+
+	/* restore parent */
+	if (clk->ops->set_parent) {
+		p_index = clk_fetch_parent_index(clk, clk->parent);
+
+		if (p_index != clk->ops->get_parent(clk->hw))
+			ret = clk->ops->set_parent(clk->hw, p_index);
+
+		if (ret) {
+			pr_err("%s: Fail to set parent %s\n",
+			       __func__, clk->name);
+			goto out;
+		}
+	}
+
+	/* restore rate */
+	if (clk->ops->set_rate) {
+		if (clk->parent)
+			parent_rate = clk->parent->rate;
+
+		rate = clk->ops->recalc_rate(clk->hw, parent_rate);
+
+		if (rate != clk->rate)
+			ret = clk->ops->set_rate(clk->hw, clk->rate,
+						 parent_rate);
+
+		if (ret) {
+			pr_err("%s: Fail to set rate %s\n",
+			       __func__, clk->name);
+			goto out;
+		}
+	}
+
+	/* restore prepare status */
+	if (clk->ops->prepare && clk->prepare_count) {
+		if (clk->ops->is_prepared) {
+			if (!clk->ops->is_prepared(clk->hw))
+				ret = clk->ops->prepare(clk->hw);
+		} else {
+			ret = clk->ops->prepare(clk->hw);
+		}
+		if (ret) {
+			pr_err("%s: Fail to prepare %s\n",
+			       __func__, clk->name);
+			goto out;
+		}
+	}
+
+	/* restore enable status */
+	if (clk->ops->enable && clk->enable_count) {
+		if (clk->ops->is_enabled) {
+			if (!clk->ops->is_enabled(clk->hw))
+				ret = clk->ops->enable(clk->hw);
+		} else {
+			ret = clk->ops->enable(clk->hw);
+		}
+		if (ret) {
+			pr_err("%s: Fail to enable %s\n",
+			       __func__, clk->name);
+			goto out;
+		}
+	}
+	if (clk->ops->disable && !clk->enable_count) {
+		if (clk->ops->is_enabled) {
+			if (clk->ops->is_enabled(clk->hw))
+				clk->ops->disable(clk->hw);
+		} else {
+			clk->ops->disable(clk->hw);
+		}
+	}
+
+	/* restore unprepare status */
+	if (clk->ops->unprepare && !clk->prepare_count) {
+		if (clk->ops->is_prepared) {
+			if (!clk->ops->is_prepared(clk->hw))
+				clk->ops->unprepare(clk->hw);
+		} else {
+			clk->ops->unprepare(clk->hw);
+		}
+	}
+
+out:
+	return ret;
+}
+
+static int _clk_resume(struct clk_core *clk)
+{
+	struct clk_core *child;
+	int ret = 0;
+
+	if (!clk)
+		return 0;
+
+	if (clk->ops->resume)
+		ret = clk->ops->resume(clk->hw);
+	else
+		ret = __clk_resume(clk);
+
+	if (ret)
+		return ret;
+
+	hlist_for_each_entry(child, &clk->children, child_node) {
+		ret = _clk_resume(child);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
+}
+
+void clk_resume(void)
+{
+	struct clk_core *clk;
+
+	hlist_for_each_entry(clk, &clk_root_list, child_node)
+		_clk_resume(clk);
+
+	hlist_for_each_entry(clk, &clk_orphan_list, child_node)
+		_clk_resume(clk);
+}
+
+int __clk_suspend(struct clk_core *clk)
+{
+	/* Currently, Nothing to do. Could be used in future */
+	return 0;
+}
+
+static int _clk_suspend(struct clk_core *clk)
+{
+	struct clk *child;
+	int ret = 0;
+
+	if (!clk)
+		return 0;
+
+	hlist_for_each_entry(child, &clk->children, child_node) {
+		ret = _clk_suspend(child);
+		if (ret)
+			return ret;
+	}
+
+	if (clk->ops->suspend)
+		return clk->ops->suspend(clk->hw);
+
+	return __clk_suspend(clk);
+}
+
+int clk_suspend(void)
+{
+	struct clk_core *clk, *clkerr;
+	int ret;
+
+	hlist_for_each_entry(clk, &clk_root_list, child_node) {
+		ret = _clk_suspend(clk);
+		if (ret) {
+			/* Call resume of suspended clocks if error */
+			hlist_for_each_entry(clkerr, &clk_root_list,
+					     child_node) {
+				if (clkerr == clk)
+					goto out;
+				_clk_resume(clkerr);
+			}
+			goto out;
+		}
+	}
+
+	hlist_for_each_entry(clk, &clk_orphan_list, child_node) {
+		ret = _clk_suspend(clk);
+		if (ret) {
+			/* Call resume of suspended clocks if error */
+			hlist_for_each_entry(clkerr, &clk_root_list,
+					     child_node)
+				_clk_resume(clkerr);
+			hlist_for_each_entry(clkerr, &clk_orphan_list,
+					     child_node) {
+				if (clkerr == clk)
+					goto out;
+				_clk_resume(clkerr);
+			}
+			goto out;
+		}
+	}
+
+out:
+	return ret;
+}
+#endif
+
  #ifdef CONFIG_OF
  /**
   * struct of_clk_provider - Clock provider registration structure

include/linux/clk-provider.h +21 -0

index 5591ea7..ec6438d 100644
@@ -151,6 +151,18 @@ struct dentry;
   *		prepare_lock held.  Returns 0 on success, -EERROR otherwise.
   *
   *
+ * @suspend:	Called (if defined) when the system is about to enter
+ *		Suspend. Framework defined __clk_suspend is called, if
+ *		this callback is not defined. Optionally the driver could
+ *		also call __clk_suspend inside this callback.
+ *		Returns 0 on success, -EERROR otherwise.
+ *
+ * @resume:	Called (if defined) when the system is about to exit
+ *		Suspend. Framework defined __clk_resume is called, if
+ *		this callback is not defined. Optionally the driver could
+ *		also call __clk_resume inside this callback.
+ *		Returns 0 on success, -EERROR otherwise.
+ *
   * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow
   * implementations to split any work between atomic (enable) and sleepable
   * (prepare) contexts.  If enabling a clock requires code that might sleep,

@@ -194,6 +206,10 @@ struct clk_ops {
  	int		(*set_phase)(struct clk_hw *hw, int degrees);
  	void		(*init)(struct clk_hw *hw);
  	int		(*debug_init)(struct clk_hw *hw, struct dentry *dentry);
+#ifdef CONFIG_PM_SLEEP
+	int             (*suspend)(struct clk_hw *hw);
+	int             (*resume)(struct clk_hw *hw);
+#endif
  };
 
  /**

@@ -596,6 +612,11 @@ static inline void __clk_hw_set_clk(struct clk_hw *dst, struct clk_hw *src)
  	dst->core = src->core;
  }
 
+#ifdef CONFIG_PM_SLEEP
+int __clk_suspend(struct clk_core *clk);
+int __clk_resume(struct clk_core *clk);
+#endif
+
  /*
   * FIXME clock api without lock protection
   */

include/linux/clk.h +23 -0

index 68c16a6..5e6a636 100644
@@ -394,6 +394,23 @@ struct clk *clk_get_parent(struct clk *clk);
   */
  struct clk *clk_get_sys(const char *dev_id, const char *con_id);
 
+#ifdef CONFIG_PM_SLEEP
+/**
+ * clk_suspend - Called by the suspend framework before entering System Suspend
+ *
+ * Returns success (0) or negative errno
+ * Called with Interrupts disabled
+ */
+int clk_suspend(void);
+
+/**
+ * clk_resume - Called by the suspend framework after exiting System Suspend
+ *
+ * Called with Interrupts disabled
+ */
+void clk_resume(void);
+#endif
+
  #else /* !CONFIG_HAVE_CLK */
 
  static inline struct clk *clk_get(struct device *dev, const char *id)

@@ -447,6 +464,12 @@ static inline struct clk *clk_get_parent(struct clk *clk)
  	return NULL;
  }
 
+#ifdef CONFIG_PM_SLEEP
+static inline int clk_suspend(void) {}
+
+static inline void clk_resume(void) {}
+#endif
+
  #endif
 
  /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */

kernel/kexec.c +6 -0

index 38c25b1..28bce76 100644
@@ -36,6 +36,7 @@
  #include <linux/syscore_ops.h>
  #include <linux/compiler.h>
  #include <linux/hugetlb.h>
+#include <linux/clk.h>
 
  #include <asm/page.h>
  #include <asm/uaccess.h>

@@ -2724,6 +2725,9 @@ int kernel_kexec(void)
  		error = syscore_suspend();
  		if (error)
  			goto Enable_irqs;
+		error = clk_suspend();
+		if (error)
+			goto Resume_syscore;
  	} else
  #endif
  	{

@@ -2746,6 +2750,8 @@ int kernel_kexec(void)
 
  #ifdef CONFIG_KEXEC_JUMP
  	if (kexec_image->preserve_context) {
+		clk_resume();
+ Resume_syscore:
  		syscore_resume();
   Enable_irqs:
  		local_irq_enable();

kernel/power/hibernate.c +16 -0

index 2329daa..f9b45ff 100644
@@ -30,6 +30,7 @@
  #include <linux/genhd.h>
  #include <linux/ktime.h>
  #include <trace/events/power.h>
+#include <linux/clk.h>
 
  #include "power.h"
 

@@ -292,6 +293,12 @@ static int create_image(int platform_mode)
  		goto Enable_irqs;
  	}
 
+	error = clk_suspend();
+	if (error) {
+		pr_err("PM: Clocks Suspend failed aborting hibernation\n");
+		goto Power_up;
+	}
+
  	if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
  		goto Power_up;
 

@@ -310,6 +317,7 @@ static int create_image(int platform_mode)
 
  	platform_leave(platform_mode);
 
+	clk_resume();
   Power_up:
  	syscore_resume();
 

@@ -442,6 +450,10 @@ static int resume_target_kernel(bool platform_mode)
  	if (error)
  		goto Enable_irqs;
 
+	error = clk_suspend();
+	if (error)
+		goto Resume_syscore;
+
  	save_processor_state();
  	error = restore_highmem();
  	if (!error) {

@@ -467,6 +479,8 @@ static int resume_target_kernel(bool platform_mode)
  	restore_processor_state();
  	touch_softlockup_watchdog();
 
+	clk_resume();
+ Resume_syscore:
  	syscore_resume();
 
   Enable_irqs:

@@ -556,6 +570,7 @@ int hibernation_platform_enter(void)
 
  	local_irq_disable();
  	syscore_suspend();
+	clk_suspend();
  	if (pm_wakeup_pending()) {
  		error = -EAGAIN;
  		goto Power_up;

@@ -566,6 +581,7 @@ int hibernation_platform_enter(void)
  	while (1);
 
   Power_up:
+	clk_resume();
  	syscore_resume();
  	local_irq_enable();
  	enable_nonboot_cpus();

kernel/power/suspend.c +7 -0

index b7d6b3a..3a9abb7 100644
@@ -28,6 +28,7 @@
  #include <linux/ftrace.h>
  #include <trace/events/power.h>
  #include <linux/compiler.h>
+#include <linux/clk.h>
 
  #include "power.h"
 

@@ -349,6 +350,10 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
 
  	error = syscore_suspend();
  	if (!error) {
+		error = clk_suspend();
+		if (error)
+			goto Resume_syscore;
+
  		*wakeup = pm_wakeup_pending();
  		if (!(suspend_test(TEST_CORE) || *wakeup)) {
  			trace_suspend_resume(TPS("machine_suspend"),

@@ -358,6 +363,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
  				state, false);
  			events_check_enabled = false;
  		}
+		clk_resume();
+Resume_syscore:
  		syscore_resume();
  	}