amd/stoneyridge: Add PM1 wake status to boot log

Print the wake status bits to the console.  The format is kept similar
to Intel's to maintain compatilibity with inspection utilities.  Add
relevant wake events from the register to the ELOG.  Clear the register
before continuing.

TEST=Inspect console and ELOG for Grunt
BUG=b:75020968

Change-Id: Idc9d12326abb290e4f7a5c60677eb6e057d475b2
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/25300
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Marc Jones <marc@marcjonesconsulting.com>
diff --git a/src/soc/amd/stoneyridge/southbridge.c b/src/soc/amd/stoneyridge/southbridge.c
index 55e3956..a2a54c2 100644
--- a/src/soc/amd/stoneyridge/southbridge.c
+++ b/src/soc/amd/stoneyridge/southbridge.c
@@ -23,6 +23,7 @@
 #include <device/pci_ids.h>
 #include <device/pci_ops.h>
 #include <cbmem.h>
+#include <elog.h>
 #include <amdblocks/amd_pci_util.h>
 #include <soc/southbridge.h>
 #include <soc/smi.h>
@@ -604,9 +605,79 @@
 				PM_ACPI_TIMER_EN_EN);
 }
 
+static void print_num_status_bits(int num_bits, uint32_t status,
+				  const char *const bit_names[])
+{
+	int i;
+
+	if (!status)
+		return;
+
+	for (i = num_bits - 1; i >= 0; i--) {
+		if (status & (1 << i)) {
+			if (bit_names[i])
+				printk(BIOS_DEBUG, "%s ", bit_names[i]);
+			else
+				printk(BIOS_DEBUG, "BIT%d ", i);
+		}
+	}
+}
+
+static uint16_t reset_pm1_status(void)
+{
+	uint16_t pm1_sts = inw(ACPI_PM_EVT_BLK);
+	outw(pm1_sts, ACPI_PM_EVT_BLK);
+	return pm1_sts;
+}
+
+static uint16_t print_pm1_status(uint16_t pm1_sts)
+{
+	static const char *const pm1_sts_bits[] = {
+		[0] = "TMROF",
+		[4] = "BMSTATUS",
+		[5] = "GBL",
+		[8] = "PWRBTN",
+		[10] = "RTC",
+		[14] = "PCIEXPWAK",
+		[15] = "WAK",
+	};
+
+	if (!pm1_sts)
+		return 0;
+
+	printk(BIOS_SPEW, "PM1_STS: ");
+	print_num_status_bits(ARRAY_SIZE(pm1_sts_bits), pm1_sts, pm1_sts_bits);
+	printk(BIOS_SPEW, "\n");
+
+	return pm1_sts;
+}
+
+static void sb_log_pm1_status(uint16_t pm1_sts)
+{
+	if (!IS_ENABLED(CONFIG_ELOG))
+		return;
+
+	if (pm1_sts & PWRBTN_STS)
+		elog_add_event_wake(ELOG_WAKE_SOURCE_PWRBTN, 0);
+
+	if (pm1_sts & RTC_STS)
+		elog_add_event_wake(ELOG_WAKE_SOURCE_RTC, 0);
+
+	if (pm1_sts & PCIEXPWAK_STS)
+		elog_add_event_wake(ELOG_WAKE_SOURCE_PCIE, 0);
+}
+
+static void sb_clear_pm1_status(void)
+{
+	uint16_t pm1_sts = reset_pm1_status();
+	sb_log_pm1_status(pm1_sts);
+	print_pm1_status(pm1_sts);
+}
+
 void southbridge_init(void *chip_info)
 {
 	sb_init_acpi_ports();
+	sb_clear_pm1_status();
 }
 
 void southbridge_final(void *chip_info)