board: st: add generic board for STM32MP1 family

Add first support for STM32MP157C-ED1 board with "Basic" boot chain
1/ Boot Rom: load SPL with STM32 image header in SYSRAM
2/ SPL: power up and initialize the DDR and load U-Boot image
        from SDCARD in DDR
3/ U-Boot: search and load extlinux.conf in SDCARD
           (DISTRO activated)

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/board/st/stm32mp1/spl.c b/board/st/stm32mp1/spl.c
new file mode 100644
index 0000000..b7e5f24
--- /dev/null
+++ b/board/st/stm32mp1/spl.c
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier:	GPL-2.0+	BSD-3-Clause
+ */
+
+#include <config.h>
+#include <common.h>
+#include <spl.h>
+#include <dm.h>
+#include <ram.h>
+#include <asm/io.h>
+#include <post.h>
+#include <power/pmic.h>
+#include <power/stpmu1.h>
+#include <asm/arch/ddr.h>
+
+void spl_board_init(void)
+{
+	/* Keep vdd on during the reset cycle */
+#if defined(CONFIG_PMIC_STPMU1) && defined(CONFIG_SPL_POWER_SUPPORT)
+	struct udevice *dev;
+	int ret;
+
+	ret = uclass_get_device_by_driver(UCLASS_PMIC,
+					  DM_GET_DRIVER(pmic_stpmu1), &dev);
+	if (!ret)
+		pmic_clrsetbits(dev,
+				STPMU1_MASK_RESET_BUCK,
+				STPMU1_MASK_RESET_BUCK3,
+				STPMU1_MASK_RESET_BUCK3);
+#endif
+}