1 files changed, 76 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index f391948c76b9..7fb033eca0a5 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -1081,6 +1081,82 @@ int pwrdm_post_transition(struct powerdomain *pwrdm)
 }
 
 /**
+ * pwrdm_get_valid_lp_state() - Find best match deep power state
+ * @pwrdm:	power domain for which we want to find best match
+ * @is_logic_state: Are we looking for logic state match here? Should
+ *		    be one of PWRDM_xxx macro values
+ * @req_state:	requested power state
+ *
+ * Returns: closest match for requested power state. default fallback
+ * is RET for logic state and ON for power state.
+ *
+ * This does a search from the power domain data looking for the
+ * closest valid power domain state that the hardware can achieve.
+ * PRCM definitions for PWRSTCTRL allows us to program whatever
+ * configuration we'd like, and PRCM will actually attempt such
+ * a transition, however if the powerdomain does not actually support it,
+ * we endup with a hung system. The valid power domain states are already
+ * available in our powerdomain data files. So this function tries to do
+ * the following:
+ * a) find if we have an exact match to the request - no issues.
+ * b) else find if a deeper power state is possible.
+ * c) failing which, it tries to find closest higher power state for the
+ * request.
+ */
+u8 pwrdm_get_valid_lp_state(struct powerdomain *pwrdm,
+			    bool is_logic_state, u8 req_state)
+{
+	u8 pwrdm_states = is_logic_state ? pwrdm->pwrsts_logic_ret :
+			pwrdm->pwrsts;
+	/* For logic, ret is highest and others, ON is highest */
+	u8 default_pwrst = is_logic_state ? PWRDM_POWER_RET : PWRDM_POWER_ON;
+	u8 new_pwrst;
+	bool found;
+
+	/* If it is already supported, nothing to search */
+	if (pwrdm_states & BIT(req_state))
+		return req_state;
+
+	if (!req_state)
+		goto up_search;
+
+	/*
+	 * So, we dont have a exact match
+	 * Can we get a deeper power state match?
+	 */
+	new_pwrst = req_state - 1;
+	found = true;
+	while (!(pwrdm_states & BIT(new_pwrst))) {
+		/* No match even at OFF? Not available */
+		if (new_pwrst == PWRDM_POWER_OFF) {
+			found = false;
+			break;
+		}
+		new_pwrst--;
+	}
+
+	if (found)
+		goto done;
+
+up_search:
+	/* OK, no deeper ones, can we get a higher match? */
+	new_pwrst = req_state + 1;
+	while (!(pwrdm_states & BIT(new_pwrst))) {
+		if (new_pwrst > PWRDM_POWER_ON) {
+			WARN(1, "powerdomain: %s: Fix max powerstate to ON\n",
+			     pwrdm->name);
+			return PWRDM_POWER_ON;
+		}
+
+		if (new_pwrst == default_pwrst)
+			break;
+		new_pwrst++;
+	}
+done:
+	return new_pwrst;
+}
+
+/**
  * omap_set_pwrdm_state - change a powerdomain's current power state
  * @pwrdm: struct powerdomain * to change the power state of
  * @pwrst: power state to change to