feat(imx8m): add the ddr frequency change support for imx8m family

Add the DDR frequency change support.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: If1167785796b8678c351569b83d2922c66f6e530
diff --git a/plat/imx/imx8m/include/dram.h b/plat/imx/imx8m/include/dram.h
index 3b81801..ad11a27 100644
--- a/plat/imx/imx8m/include/dram.h
+++ b/plat/imx/imx8m/include/dram.h
@@ -50,9 +50,13 @@
 struct dram_info {
 	int dram_type;
 	unsigned int num_rank;
+	uint32_t num_fsp;
 	int current_fsp;
 	int boot_fsp;
+	bool bypass_mode;
 	struct dram_timing_info *timing_info;
+	/* mr, emr, emr2, emr3, mr11, mr12, mr22, mr14 */
+	uint32_t mr_table[3][8];
 };
 
 extern struct dram_info dram_info;
@@ -65,4 +69,10 @@
 void dram_enter_retention(void);
 void dram_exit_retention(void);
 
+void dram_clock_switch(unsigned int target_drate, bool bypass_mode);
+
+/* dram frequency change */
+void lpddr4_swffc(struct dram_info *info, unsigned int init_fsp, unsigned int fsp_index);
+void ddr4_swffc(struct dram_info *dram_info, unsigned int pstate);
+
 #endif /* DRAM_H */