OMAP3: cpuidle: Update statistics for correct state

When 'enable_off_mode' is 0, the target power state for MPU
and CORE was locally changed to PWRDM_POWER_RET but, the
statistics are updated for idle state originally selected
by the governor.

This patch 'invalidates' the idle states that lead either of
MPU or Core to PWRDM_POWER_OFF state when 'enable_off_mode'
is '0'. The states are valid once 'enable_off_mode' is set
to '1'.

Added function next_valid_state() to check if current state
is valid; else get the next valid state. It is called from
omap3_enter_idle_bm().

Signed-off-by: Sanjeev Premi <premi@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 90 insertions, 8 deletions

diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-omap2/cpuidle34xx.c
index 12f0cbfc289..ff1ad3d06ce 100644
--- a/arch/arm/mach-omap2/cpuidle34xx.c
+++ b/arch/arm/mach-omap2/cpuidle34xx.c
@@ -45,6 +45,8 @@
 #define OMAP3_STATE_C6 5 /* C6 - MPU OFF + Core RET */
 #define OMAP3_STATE_C7 6 /* C7 - MPU OFF + Core OFF */
 
+#define OMAP3_STATE_MAX OMAP3_STATE_C7
+
 struct omap3_processor_cx {
         u8 valid;
         u8 type;
@@ -104,13 +106,6 @@ static int omap3_enter_idle(struct cpuidle_device *dev,
         local_irq_disable();
         local_fiq_disable();
 
-        if (!enable_off_mode) {
-                if (mpu_state < PWRDM_POWER_RET)
-                        mpu_state = PWRDM_POWER_RET;
-                if (core_state < PWRDM_POWER_RET)
-                        core_state = PWRDM_POWER_RET;
-        }
-
         pwrdm_set_next_pwrst(mpu_pd, mpu_state);
         pwrdm_set_next_pwrst(core_pd, core_state);
 
@@ -141,6 +136,67 @@ return_sleep_time:
 }
 
 /**
+ * next_valid_state - Find next valid c-state
+ * @dev: cpuidle device
+ * @state: Currently selected c-state
+ *
+ * If the current state is valid, it is returned back to the caller.
+ * Else, this function searches for a lower c-state which is still
+ * valid (as defined in omap3_power_states[]).
+ */
+static struct cpuidle_state *next_valid_state(struct cpuidle_device *dev,
+                                                struct cpuidle_state *curr)
+{
+        struct cpuidle_state *next = NULL;
+        struct omap3_processor_cx *cx;
+
+        cx = (struct omap3_processor_cx *)cpuidle_get_statedata(curr);
+
+        /* Check if current state is valid */
+        if (cx->valid) {
+                return curr;
+        } else {
+                u8 idx = OMAP3_STATE_MAX;
+
+                /*
+                 * Reach the current state starting at highest C-state
+                 */
+                for (; idx >= OMAP3_STATE_C1; idx--) {
+                        if (&dev->states[idx] == curr) {
+                                next = &dev->states[idx];
+                                break;
+                        }
+                }
+
+                /*
+                 * Should never hit this condition.
+                 */
+                WARN_ON(next == NULL);
+
+                /*
+                 * Drop to next valid state.
+                 * Start search from the next (lower) state.
+                 */
+                idx--;
+                for (; idx >= OMAP3_STATE_C1; idx--) {
+                        struct omap3_processor_cx *cx;
+
+                        cx = cpuidle_get_statedata(&dev->states[idx]);
+                        if (cx->valid) {
+                                next = &dev->states[idx];
+                                break;
+                        }
+                }
+                /*
+                 * C1 and C2 are always valid.
+                 * So, no need to check for 'next==NULL' outside this loop.
+                 */
+        }
+
+        return next;
+}
+
+/**
  * omap3_enter_idle_bm - Checks for any bus activity
  * @dev: cpuidle device
  * @state: The target state to be programmed
@@ -152,7 +208,7 @@ return_sleep_time:
 static int omap3_enter_idle_bm(struct cpuidle_device *dev,
                                struct cpuidle_state *state)
 {
-        struct cpuidle_state *new_state = state;
+        struct cpuidle_state *new_state = next_valid_state(dev, state);
 
         if ((state->flags & CPUIDLE_FLAG_CHECK_BM) && omap3_idle_bm_check()) {
                 BUG_ON(!dev->safe_state);
@@ -165,6 +221,30 @@ static int omap3_enter_idle_bm(struct cpuidle_device *dev,
 
 DEFINE_PER_CPU(struct cpuidle_device, omap3_idle_dev);
 
+/**
+ * omap3_cpuidle_update_states - Update the cpuidle states.
+ *
+ * Currently, this function toggles the validity of idle states based upon
+ * the flag 'enable_off_mode'. When the flag is set all states are valid.
+ * Else, states leading to OFF state set to be invalid.
+ */
+void omap3_cpuidle_update_states(void)
+{
+        int i;
+
+        for (i = OMAP3_STATE_C1; i < OMAP3_MAX_STATES; i++) {
+                struct omap3_processor_cx *cx = &omap3_power_states[i];
+
+                if (enable_off_mode) {
+                        cx->valid = 1;
+                } else {
+                        if ((cx->mpu_state == PWRDM_POWER_OFF) ||
+                                (cx->core_state == PWRDM_POWER_OFF))
+                                cx->valid = 0;
+                }
+        }
+}
+
 /* omap3_init_power_states - Initialises the OMAP3 specific C states.
  *
  * Below is the desciption of each C state.
@@ -302,6 +382,8 @@ int __init omap3_idle_init(void)
                 return -EINVAL;
         dev->state_count = count;
 
+        omap3_cpuidle_update_states();
+
         if (cpuidle_register_device(dev)) {
                 printk(KERN_ERR "%s: CPUidle register device failed\n",
                        __func__);