soc/intel/xeon_sp: Add RTC failure checking

Add a weak function mainboard_rtc_failed() for mainboard customization.

Check RTC_PWR_STS bit for RTC battery removal or CMOS clear jumper
triggered event.

Signed-off-by: Jingle Hsu <jingle_hsu@wiwynn.com>
Change-Id: Ic6da84277e71a5c51dfa4d97d5d0c0184478e8f0
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43004
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/intel/xeon_sp/Makefile.inc

@@ -6,7 +6,7 @@ subdirs-$(CONFIG_SOC_INTEL_SKYLAKE_SP) += skx
 subdirs-$(CONFIG_SOC_INTEL_COOPERLAKE_SP) += cpx
 
 bootblock-y += bootblock.c spi.c lpc.c gpio.c pch.c
-romstage-y += romstage.c reset.c util.c spi.c gpio.c
+romstage-y += romstage.c reset.c util.c spi.c gpio.c pmutil.c
 ramstage-y += uncore.c reset.c util.c lpc.c spi.c gpio.c
 postcar-y += spi.c
 

src/soc/intel/xeon_sp/include/soc/pmc.h

@@ -25,6 +25,6 @@
 #define GEN_PMCON_B		0xa4
 #define  SLP_STR_POL_LOCK	(1 << 18)
 #define  ACPI_BASE_LOCK		(1 << 17)
-
+#define  RTC_BATTERY_DEAD	(1 << 2)
 
 #endif

src/soc/intel/xeon_sp/include/soc/romstage.h

@@ -8,5 +8,6 @@
 
 /* These functions are weak and can be overridden by a mainboard functions. */
 void mainboard_memory_init_params(FSPM_UPD * mupd);
+void mainboard_rtc_failed(void);
 
 #endif /* _SOC_ROMSTAGE_H_ */

src/soc/intel/xeon_sp/pmutil.c

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/*
+ * Helper functions for dealing with power management registers
+ * and the differences between PCH variants.
+ */
+
+#include <intelblocks/rtc.h>
+#include <soc/pmc.h>
+#include <soc/pci_devs.h>
+#include <device/pci.h>
+#include <console/console.h>
+
+int soc_get_rtc_failed(void)
+{
+	uint32_t pmcon_b = pci_s_read_config32(PCH_DEV_PMC, GEN_PMCON_B);
+	int rtc_fail = !!(pmcon_b & RTC_BATTERY_DEAD);
+
+	if (rtc_fail)
+		printk(BIOS_ERR, "%s: RTC battery dead or removed\n", __func__);
+
+	return rtc_fail;
+}

src/soc/intel/xeon_sp/romstage.c

@@ -18,6 +18,8 @@ asmlinkage void car_stage_entry(void)
 
 	console_init();
 	rtc_init();
+	if (soc_get_rtc_failed())
+		mainboard_rtc_failed();
 
 	fsp_memory_init(false);
 	printk(BIOS_DEBUG, "coreboot fsp_memory_init finished...\n");
@@ -47,3 +49,8 @@ __weak void mainboard_memory_init_params(FSPM_UPD *mupd)
 {
 	printk(BIOS_SPEW, "WARNING: using default FSP-M parameters!\n");
 }
+
+__weak void mainboard_rtc_failed(void)
+{
+
+}