feat(st-ddr): add read valid training support

Add the read data eye training = training for optimal read valid placement
(RVTRN) when the built-in calibration is executed for LPDDR2 and LPDDR3.

Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Change-Id: I7ac1c77c21ebc30315b532741f2f255c2312d5b2
diff --git a/drivers/st/ddr/stm32mp1_ddr.c b/drivers/st/ddr/stm32mp1_ddr.c
index 721110c..83dff04 100644
--- a/drivers/st/ddr/stm32mp1_ddr.c
+++ b/drivers/st/ddr/stm32mp1_ddr.c
@@ -868,9 +868,14 @@
 	/*
 	 * 10. configure PUBL PIR register to specify which training step
 	 * to run
-	 * Warning : RVTRN  is not supported by this PUBL
+	 * RVTRN is executed only on LPDDR2/LPDDR3
 	 */
-	stm32mp1_ddrphy_init(priv->phy, DDRPHYC_PIR_QSTRN);
+	pir = DDRPHYC_PIR_QSTRN;
+	if ((config->c_reg.mstr & DDRCTRL_MSTR_DDR3) == 0U) {
+		pir |= DDRPHYC_PIR_RVTRN;
+	}
+
+	stm32mp1_ddrphy_init(priv->phy, pir);
 
 	/* 11. monitor PUB PGSR.IDONE to poll cpmpletion of training sequence */
 	stm32mp1_ddrphy_idone_wait(priv->phy);