icnss2: Add support for Hibernate low power mode

Hibernate is a system wide power mode during which Modem
would be brought down along with DDR and the RAM contents
would be saved on the disk (suspend-to-Disk).

Modem would be do graceful shutdown in Hibernate mode,
so BEFORE_SUBSYS_DOWN notification will be received.
Based on dtsi node "is_low_power", if BEFORE_SUBSYS_DOWN
with notif->crashed bit not set is received, platform
driver will trigger an idle shutdown and set low power mode.

On AFTER_SUBSYS_DOWN notification, low power mode will be
cleared if it was set and ramdump collection will happen
only in case of crash.

Change-Id: I7b618e7c23950e4055079cde237ed75d6861620f
CRs-Fixed: 3394501

icnss2/main.c

@@ -2171,10 +2171,25 @@ static int icnss_modem_notifier_nb(struct notifier_block *nb,
 
 	switch (code) {
 	case QCOM_SSR_BEFORE_SHUTDOWN:
+		if (!notif->crashed &&
+		    priv->low_power_support) { /* Hibernate */
+			if (test_bit(ICNSS_MODE_ON, &priv->state))
+				icnss_driver_event_post(
+					priv, ICNSS_DRIVER_EVENT_IDLE_SHUTDOWN,
+					ICNSS_EVENT_SYNC_UNINTERRUPTIBLE, NULL);
+			set_bit(ICNSS_LOW_POWER, &priv->state);
+		}
 		break;
 	case QCOM_SSR_AFTER_SHUTDOWN:
-		icnss_pr_info("Collecting msa0 segment dump\n");
-		icnss_msa0_ramdump(priv);
+		/* Collect ramdump only when there was a crash. */
+		if (notif->crashed) {
+			icnss_pr_info("Collecting msa0 segment dump\n");
+			icnss_msa0_ramdump(priv);
+		}
+
+		if (test_bit(ICNSS_LOW_POWER, &priv->state) &&
+			     priv->low_power_support)
+			clear_bit(ICNSS_LOW_POWER, &priv->state);
 		goto out;
 	default:
 		goto out;
@@ -4049,6 +4064,12 @@ static int icnss_resource_parse(struct icnss_priv *priv)
 			}
 		}
 
+		if (of_property_read_bool(pdev->dev.of_node,
+					  "qcom,is_low_power")) {
+			priv->low_power_support = true;
+			icnss_pr_dbg("Deep Sleep/Hibernate mode supported\n");
+		}
+
 		if (of_property_read_u32(pdev->dev.of_node, "qcom,rf_subtype",
 					 &priv->rf_subtype) == 0) {
 			priv->is_rf_subtype_valid = true;

icnss2/main.h

@@ -499,6 +499,7 @@ struct icnss_priv {
 	struct workqueue_struct *soc_update_wq;
 	unsigned long device_config;
 	bool wpss_supported;
+	u8 low_power_support;
 	bool is_rf_subtype_valid;
 	u32 rf_subtype;
 	u8 is_slate_rfa;