[PATCHv5 02/10] ARM: OMAP3+: voltage: add support for voltagedomain usecounts

[t-kristo@ti.com (Tero Kristo)]

These are updated based on powerdomain usecounts. Also added support
for voltdm->sleep and voltdm->wakeup calls that will be invoked once
voltagedomain enters sleep or wakes up based on usecount numbers. These
will be used for controlling voltage scaling functionality.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@ti.com>
---
 arch/arm/mach-omap2/powerdomain.c |   17 +++++++++-
 arch/arm/mach-omap2/voltage.c     |   62 +++++++++++++++++++++++++++++++++++++
 arch/arm/mach-omap2/voltage.h     |   13 ++++++++
 3 files changed, 91 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index ba49029..ca54aec 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -1475,10 +1477,16 @@ int pwrdm_state_switch(struct powerdomain *pwrdm)
  */
 void pwrdm_clkdm_enable(struct powerdomain *pwrdm)
 {
+	unsigned long flags;
+
 	if (!pwrdm)
 		return;
 
-	atomic_inc(&pwrdm->usecount);
+	if (atomic_inc_return(&pwrdm->usecount) == 1) {
+		spin_lock_irqsave(&pwrdm->lock, flags);
+		voltdm_pwrdm_enable(pwrdm->voltdm.ptr);
+		spin_unlock_irqrestore(&pwrdm->lock, flags);
+	}
 }
 
 /**
@@ -1492,12 +1500,19 @@ void pwrdm_clkdm_enable(struct powerdomain *pwrdm)
 void pwrdm_clkdm_disable(struct powerdomain *pwrdm)
 {
 	int val;
+	unsigned long flags;
 
 	if (!pwrdm)
 		return;
 
 	val = atomic_dec_return(&pwrdm->usecount);
 
+	if (!val) {
+		spin_lock_irqsave(&pwrdm->lock, flags);
+		voltdm_pwrdm_disable(pwrdm->voltdm.ptr);
+		spin_unlock_irqrestore(&pwrdm->lock, flags);
+	}
+
 	WARN_ON(val < 0);
 }
 
diff --git a/arch/arm/mach-omap2/voltage.c b/arch/arm/mach-omap2/voltage.c
index 4dc60e8..9eb1a4b 100644
--- a/arch/arm/mach-omap2/voltage.c
+++ b/arch/arm/mach-omap2/voltage.c
@@ -340,6 +340,67 @@ int voltdm_add_pwrdm(struct voltagedomain *voltdm, struct powerdomain *pwrdm)
 }
 
 /**
+ * voltdm_pwrdm_enable - increase usecount for a voltagedomain
+ * @voltdm: struct voltagedomain * to increase count for
+ *
+ * Increases usecount for a given voltagedomain. If the usecount reaches
+ * 1, the domain is awakened from idle and the function will call the
+ * voltagedomain->wakeup callback for this domain.
+ */
+void voltdm_pwrdm_enable(struct voltagedomain *voltdm)
+{
+	unsigned long flags;
+
+	if (!voltdm)
+		return;
+
+	if (atomic_inc_return(&voltdm->usecount) == 1 && voltdm->wakeup) {
+		spin_lock_irqsave(&voltdm->lock, flags);
+		voltdm->wakeup(voltdm);
+		spin_unlock_irqrestore(&voltdm->lock, flags);
+	}
+}
+
+/**
+ * voltdm_pwrdm_disable - decrease usecount for a voltagedomain
+ * @voltdm: struct voltagedomain * to decrease count for
+ *
+ * Decreases the usecount for a given voltagedomain. If the usecount
+ * reaches zero, the domain can idle and the function will call the
+ * voltagedomain->sleep callback, and calculate the overall target
+ * state for the voltagedomain.
+ */
+void voltdm_pwrdm_disable(struct voltagedomain *voltdm)
+{
+	u8 target_state = PWRDM_POWER_OFF;
+	int state;
+	struct powerdomain *pwrdm;
+	int val;
+	unsigned long flags;
+
+	if (!voltdm)
+		return;
+
+	val = atomic_dec_return(&voltdm->usecount);
+
+	WARN_ON(val < 0);
+
+	if (val == 0) {
+		spin_lock_irqsave(&voltdm->lock, flags);
+		/* Determine target state for voltdm */
+		list_for_each_entry(pwrdm, &voltdm->pwrdm_list, voltdm_node) {
+			state = pwrdm_read_next_pwrst(pwrdm);
+			if (state > target_state)
+				target_state = state;
+		}
+		voltdm->target_state = target_state;
+		if (voltdm->sleep)
+			voltdm->sleep(voltdm);
+		spin_unlock_irqrestore(&voltdm->lock, flags);
+	}
+}
+
+/**
  * voltdm_for_each_pwrdm - call function for each pwrdm in a voltdm
  * @voltdm: struct voltagedomain * to iterate over
  * @fn: callback function *
@@ -402,6 +463,7 @@ static int _voltdm_register(struct voltagedomain *voltdm)
 	INIT_LIST_HEAD(&voltdm->pwrdm_list);
 	list_add(&voltdm->node, &voltdm_list);
 
+	spin_lock_init(&voltdm->lock);
 	pr_debug("voltagedomain: registered %s\n", voltdm->name);
 
 	return 0;
diff --git a/arch/arm/mach-omap2/voltage.h b/arch/arm/mach-omap2/voltage.h
index 0ac2caf..7f4f99d 100644
--- a/arch/arm/mach-omap2/voltage.h
+++ b/arch/arm/mach-omap2/voltage.h
@@ -15,6 +15,7 @@
 #define __ARCH_ARM_MACH_OMAP2_VOLTAGE_H
 
 #include <linux/err.h>
+#include <linux/spinlock.h>
 
 #include <plat/voltage.h>
 
@@ -56,10 +57,14 @@ struct omap_vfsm_instance {
  * @pwrdm_list: list_head linking all powerdomains in this voltagedomain
  * @vc: pointer to VC channel associated with this voltagedomain
  * @vp: pointer to VP associated with this voltagedomain
+ * @usecount: number of users for this voltagedomain
+ * @target_state: calculated target state for the children of this domain
  * @read: read a VC/VP register
  * @write: write a VC/VP register
  * @read: read-modify-write a VC/VP register
  * @sys_clk: system clock name/frequency, used for various timing calculations
+ * @sleep: function to call once the domain enters idle
+ * @wakeup: function to call once the domain wakes up from idle
  * @scale: function used to scale the voltage of the voltagedomain
  * @nominal_volt: current nominal voltage for this voltage domain
  * @volt_data: voltage table having the distinct voltages supported
@@ -75,6 +80,9 @@ struct voltagedomain {
 	struct omap_vp_instance *vp;
 	struct omap_voltdm_pmic *pmic;
 
+	atomic_t usecount;
+	u8 target_state;
+
 	/* VC/VP register access functions: SoC specific */
 	u32 (*read) (u8 offset);
 	void (*write) (u32 val, u8 offset);
@@ -85,11 +93,14 @@ struct voltagedomain {
 		u32 rate;
 	} sys_clk;
 
+	void (*sleep) (struct voltagedomain *voltdm);
+	void (*wakeup) (struct voltagedomain *voltdm);
 	int (*scale) (struct voltagedomain *voltdm,
 		      unsigned long target_volt);
 
 	u32 nominal_volt;
 	struct omap_volt_data *volt_data;
+	spinlock_t lock;
 };
 
 /**
@@ -145,6 +156,8 @@ extern void omap44xx_voltagedomains_init(void);
 struct voltagedomain *voltdm_lookup(const char *name);
 void voltdm_init(struct voltagedomain **voltdm_list);
 int voltdm_add_pwrdm(struct voltagedomain *voltdm, struct powerdomain *pwrdm);
+void voltdm_pwrdm_enable(struct voltagedomain *voltdm);
+void voltdm_pwrdm_disable(struct voltagedomain *voltdm);
 int voltdm_for_each(int (*fn)(struct voltagedomain *voltdm, void *user),
 		    void *user);
 int voltdm_for_each_pwrdm(struct voltagedomain *voltdm,
-- 
1.7.4.1