imx: imx8ulp: add get reset cause

Add get reset cause function to show what triggerred reset.
Signed-off-by: NPeng Fan <peng.fan@nxp.com>

arch/arm/mach-imx/imx8ulp/soc.c

@@ -32,6 +32,73 @@ enum bt_mode get_boot_mode(void)
 	return LOW_POWER_BOOT;
 }
 
+#define CMC_SRS_TAMPER                    BIT(31)
+#define CMC_SRS_SECURITY                  BIT(30)
+#define CMC_SRS_TZWDG                     BIT(29)
+#define CMC_SRS_JTAG_RST                  BIT(28)
+#define CMC_SRS_CORE1                     BIT(16)
+#define CMC_SRS_LOCKUP                    BIT(15)
+#define CMC_SRS_SW                        BIT(14)
+#define CMC_SRS_WDG                       BIT(13)
+#define CMC_SRS_PIN_RESET                 BIT(8)
+#define CMC_SRS_WARM                      BIT(4)
+#define CMC_SRS_HVD                       BIT(3)
+#define CMC_SRS_LVD                       BIT(2)
+#define CMC_SRS_POR                       BIT(1)
+#define CMC_SRS_WUP                       BIT(0)
+
+static u32 reset_cause = -1;
+
+static char *get_reset_cause(char *ret)
+{
+	u32 cause1, cause = 0, srs = 0;
+	void __iomem *reg_ssrs = (void __iomem *)(SRC_BASE_ADDR + 0x88);
+	void __iomem *reg_srs = (void __iomem *)(SRC_BASE_ADDR + 0x80);
+
+	if (!ret)
+		return "null";
+
+	srs = readl(reg_srs);
+	cause1 = readl(reg_ssrs);
+
+	reset_cause = cause1;
+
+	cause = cause1 & (CMC_SRS_POR | CMC_SRS_WUP | CMC_SRS_WARM);
+
+	switch (cause) {
+	case CMC_SRS_POR:
+		sprintf(ret, "%s", "POR");
+		break;
+	case CMC_SRS_WUP:
+		sprintf(ret, "%s", "WUP");
+		break;
+	case CMC_SRS_WARM:
+		cause = cause1 & (CMC_SRS_WDG | CMC_SRS_SW |
+			CMC_SRS_JTAG_RST);
+		switch (cause) {
+		case CMC_SRS_WDG:
+			sprintf(ret, "%s", "WARM-WDG");
+			break;
+		case CMC_SRS_SW:
+			sprintf(ret, "%s", "WARM-SW");
+			break;
+		case CMC_SRS_JTAG_RST:
+			sprintf(ret, "%s", "WARM-JTAG");
+			break;
+		default:
+			sprintf(ret, "%s", "WARM-UNKN");
+			break;
+		}
+		break;
+	default:
+		sprintf(ret, "%s-%X", "UNKN", cause1);
+		break;
+	}
+
+	debug("[%X] SRS[%X] %X - ", cause1, srs, srs ^ cause1);
+	return ret;
+}
+
 #if defined(CONFIG_DISPLAY_CPUINFO)
 const char *get_imx_type(u32 imxtype)
 {
@@ -50,6 +117,8 @@ int print_cpuinfo(void)
 	       (cpurev & 0x000F0) >> 4, (cpurev & 0x0000F) >> 0,
 	       mxc_get_clock(MXC_ARM_CLK) / 1000000);
 
+	printf("Reset cause: %s\n", get_reset_cause(cause));
+
 	printf("Boot mode: ");
 	switch (get_boot_mode()) {
 	case LOW_POWER_BOOT: