soc/apollolake: Return correct wake status in _SWS

Wake status is calculated from the four pairs of gpe0 in
cbmem CBMEM_ID_POWER_STATE which is filled very early
in romstage and depends on the routing information in
PMC GPE_CFG register. Coreboot sets the proper value
of routing based on devicetree from pmc_init. But when
system goes to S3 on waking up PMC is writing default
values again in GPE_CFG which results in returning
wrong wake status in _SWS. This patch corrects that
behaviour by correcting the gpe0 pairs in cbmem after
PMC sets the routing table in resume path.

BUG=chrome-os-partner:54876
TEST=On resume through powerbtn, lidopen, keyboard press,  etc.
     we are getting proper wake status.

Change-Id: I5942d5c20d8c6aef73468dc611190bb7c49c7c7a
Signed-off-by: Shaunak Saha <shaunak.saha@intel.com>
Reviewed-on: https://review.coreboot.org/16040
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Brandon Breitenstein <brandon.breitenstein@intel.com>

src/soc/intel/apollolake/pmutil.c

@@ -19,6 +19,7 @@
 
 #include <arch/io.h>
 #include <console/console.h>
+#include <cbmem.h>
 #include <rules.h>
 #include <device/pci_def.h>
 #include <halt.h>
@@ -327,6 +328,30 @@ int chipset_prev_sleep_state(struct chipset_power_state *ps)
 	return prev_sleep_state;
 }
 
+/*
+ * This function re-writes the gpe0 register values in power state
+ * cbmem variable. After system wakes from sleep state internal PMC logic
+ * writes default values in GPE_CFG register which gives a wrong offset to
+ * calculate the wake reason. So we need to set it again to the routing
+ * table as per the devicetree.
+ */
+void fixup_power_state(void)
+{
+	int i;
+	struct chipset_power_state *ps;
+
+	ps = cbmem_find(CBMEM_ID_POWER_STATE);
+	if (ps == NULL)
+		return;
+
+	for (i = 0; i < GPE0_REG_MAX; i++) {
+		ps->gpe0_sts[i] = inl(ACPI_PMIO_BASE + GPE0_STS(i));
+		ps->gpe0_en[i] = inl(ACPI_PMIO_BASE + GPE0_EN(i));
+		printk(BIOS_DEBUG, "gpe0_sts[%d]: %08x gpe0_en[%d]: %08x\n",
+					i, ps->gpe0_sts[i], i, ps->gpe0_en[i]);
+	}
+}
+
 /* returns prev_sleep_state */
 int fill_power_state(struct chipset_power_state *ps)
 {