rcar_gen3: drivers: pwrc: Add DBSC4 setting before self-refresh mode

Very rarely, LPDDR4 power consumption may not decrease
In self-refresh mode.

This patch fixes the DBSC4 self-refresh mode sequence.
Signed-off-by: Yoshifumi Hosoya <yoshifumi.hosoya.wj@renesas.com>
Signed-off-by: Kenji Miyazawa <kenji.miyazawa.xt@renesas.com>
Signed-off-by: Chiaki Fujii <chiaki.fujii.wj@renesas.com>
Change-Id: I838fa0892b1caf1ecd3f04538b3427e7d971ef59

drivers/renesas/rcar/pwrc/pwrc.c

@@ -50,6 +50,7 @@ RCAR_INSTANTIATE_LOCK
 #define	DBSC4_REG_DBRFEN			(DBSC4_REG_BASE + 0x0204U)
 #define	DBSC4_REG_DBWAIT			(DBSC4_REG_BASE + 0x0210U)
 #define	DBSC4_REG_DBCALCNF			(DBSC4_REG_BASE + 0x0424U)
+#define	DBSC4_REG_DBDFIPMSTRCNF			(DBSC4_REG_BASE + 0x0520U)
 #define	DBSC4_REG_DBPDLK0			(DBSC4_REG_BASE + 0x0620U)
 #define	DBSC4_REG_DBPDRGA0			(DBSC4_REG_BASE + 0x0624U)
 #define	DBSC4_REG_DBPDRGD0			(DBSC4_REG_BASE + 0x0628U)
@@ -61,6 +62,7 @@ RCAR_INSTANTIATE_LOCK
 #define	DBSC4_BIT_DBACEN_ACCEN			((uint32_t)(1U << 0))
 #define	DBSC4_BIT_DBRFEN_ARFEN			((uint32_t)(1U << 0))
 #define	DBSC4_BIT_DBCAMxSTAT0			(0x00000001U)
+#define	DBSC4_BIT_DBDFIPMSTRCNF_PMSTREN		(0x00000001U)
 #define	DBSC4_SET_DBCMD_OPC_PRE			(0x04000000U)
 #define	DBSC4_SET_DBCMD_OPC_SR			(0x0A000000U)
 #define	DBSC4_SET_DBCMD_OPC_PD			(0x08000000U)
@@ -393,6 +395,11 @@ static void __attribute__ ((section(".system_ram")))
 
 self_refresh:
 
+	/* DFI_PHYMSTR_ACK setting */
+	mmio_write_32(DBSC4_REG_DBDFIPMSTRCNF,
+			mmio_read_32(DBSC4_REG_DBDFIPMSTRCNF) &
+			(~DBSC4_BIT_DBDFIPMSTRCNF_PMSTREN));
+
 	/* Set the Self-Refresh mode */
 	mmio_write_32(DBSC4_REG_DBACEN, 0);