2 files changed, 31 insertions, 0 deletions
diff --git a/src/soc/intel/tigerlake/include/soc/pmc.h b/src/soc/intel/tigerlake/include/soc/pmc.h
index 0f72833fbe..b7a97cc824 100644
--- a/src/soc/intel/tigerlake/include/soc/pmc.h
+++ b/src/soc/intel/tigerlake/include/soc/pmc.h
@@ -101,6 +101,30 @@ extern struct device_operations pmc_ops;
 #define   PCH2CPU_TPR_CFG_LOCK		(1 << 31)
 #define   PCH2CPU_TT_EN			(1 << 26)
 
+#define PCH_PMC_EPOC			0x18EC
+#define PCH_EPOC_2LM(__epoc)		((__epoc) & 0x1)
+/* XTAL frequency in bits 21, 20, 17 */
+#define PCH_EPOC_XTAL_FREQ(__epoc)	((((__epoc) >> 19) & 0x6) | ((__epoc) >> 17 & 0x1))
+
+/**
+ * enum pch_pmc_xtal - External crystal oscillator frequency.
+ * @XTAL_24_MHZ: 24 MHz external crystal.
+ * @XTAL_19_2_MHZ: 19.2 MHz external crystal.
+ * @XTAL_38_4_MHZ: 38.4 MHz external crystal.
+ */
+enum pch_pmc_xtal {
+	XTAL_24_MHZ,
+	XTAL_19_2_MHZ,
+	XTAL_38_4_MHZ,
+};
+
+/**
+ * pmc_get_xtal_freq() - Return frequency of external oscillator.
+ *
+ * Return &enum pch_pmc_xtal corredsponding to frequency returned by PMC.
+ */
+enum pch_pmc_xtal pmc_get_xtal_freq(void);
+
 #define PCH_PWRM_ACPI_TMR_CTL		0x18FC
 #define GPIO_GPE_CFG			0x1920
 #define  GPE0_DWX_MASK			0xf
diff --git a/src/soc/intel/tigerlake/pmc.c b/src/soc/intel/tigerlake/pmc.c
index 2d30424cd0..62e37114f3 100644
--- a/src/soc/intel/tigerlake/pmc.c
+++ b/src/soc/intel/tigerlake/pmc.c
@@ -17,6 +17,13 @@
 #include <soc/pm.h>
 #include <soc/soc_chip.h>
 
+enum pch_pmc_xtal pmc_get_xtal_freq(void)
+{
+	uint8_t *const pmcbase = pmc_mmio_regs();
+
+	return PCH_EPOC_XTAL_FREQ(read32(pmcbase + PCH_PMC_EPOC));
+}
+
 static void config_deep_sX(uint32_t offset, uint32_t mask, int sx, int enable)
 {
 	uint32_t reg;