Implement Panther Lake power sequence

Author: jackpot51

src/app/main/power/intel.c

@@ -84,6 +84,11 @@
 #define HAVE_PD_EN 0
 #endif
 
+// Introduced with Panther Lake, disabled by default
+#ifndef HAVE_VCCST_EN
+#define HAVE_VCCST_EN 0
+#endif
+
 #ifndef HAVE_XLP_OUT
 #define HAVE_XLP_OUT 1
 #endif
@@ -138,12 +143,12 @@ enum PowerState calculate_power_state(void) {
 #if CONFIG_BUS_ESPI
     // Use eSPI virtual wires if available
 
-    if (vw_get(&VW_SLP_S4_N) != VWS_HIGH) {
+    if (vw_get_ignore_invalid(&VW_SLP_S4_N) != VWS_HIGH) {
         // S4 plane not powered
         return POWER_STATE_S5;
     }
 
-    if (vw_get(&VW_SLP_S3_N) != VWS_HIGH) {
+    if (vw_get_ignore_invalid(&VW_SLP_S3_N) != VWS_HIGH) {
         // S3 plane not powered
         return POWER_STATE_S3;
     }
@@ -201,6 +206,27 @@ void power_init(void) {
     update_power_state();
 }
 
+#if HAVE_VCCST_EN
+static void power_vccst_update(void) {
+    //TODO: verify against panther lake design guide
+    static bool last_vccst_en = false;
+    bool vccst_en = gpio_get(&VCCST_EN);
+    if (vccst_en != last_vccst_en) {
+        if (vccst_en) {
+            DEBUG("%02X: VCCST_EN asserted\n", main_cycle);
+
+            // Delay for power good
+            //TODO: determine ideal delay
+            delay_ms(200);
+        } else {
+            DEBUG("%02X: VCCST_EN de-asserted\n", main_cycle);
+        }
+        GPIO_SET_DEBUG(VCCST_EN_PG, vccst_en);
+        last_vccst_en = vccst_en;
+    }
+}
+#endif
+
 void power_on(void) {
     // Configure WLAN GPIOs before powering on
     wireless_power(true);
@@ -266,6 +292,10 @@ void power_on(void) {
             break;
         }
 
+#if HAVE_VCCST_EN
+        power_vccst_update();
+#endif
+
 #if CONFIG_BUS_ESPI
         // Check for VW changes
         espi_event();
@@ -524,6 +554,10 @@ void power_event(void) {
 #endif
 #endif // HAVE_SLP_SUS_N
 
+#if HAVE_VCCST_EN
+    power_vccst_update();
+#endif
+
 #if CONFIG_BUS_ESPI
     // ESPI systems must keep S5 planes powered unless VW_SUS_PWRDN_ACK is high
     if (vw_get(&VW_SUS_PWRDN_ACK) == VWS_HIGH)

src/ec/ite/espi.c

@@ -50,6 +50,16 @@ enum VirtualWireState vw_get(struct VirtualWire *const vw) __critical {
     }
 }
 
+// Panther Lake sets validity only when signals change
+enum VirtualWireState vw_get_ignore_invalid(struct VirtualWire *const vw) __critical {
+    uint8_t index = *vw->index;
+    if (index & vw->data_mask) {
+        return VWS_HIGH;
+    } else {
+        return VWS_LOW;
+    }
+}
+
 void vw_set(struct VirtualWire *const vw, enum VirtualWireState state) __critical {
     uint8_t index = *vw->index;
     switch (state) {

src/ec/ite/include/ec/espi.h

@@ -26,6 +26,7 @@ enum VirtualWireState {
 };
 
 enum VirtualWireState vw_get(struct VirtualWire *const vw) __critical;
+enum VirtualWireState vw_get_ignore_invalid(struct VirtualWire *const vw) __critical;
 
 void vw_set(struct VirtualWire *const vw, enum VirtualWireState state) __critical;