bsh: imx8mn-smm-s2/pro: Add iMX8MN BSH SMM S2 boards

Introduce BSH SystemMaster (SMM) S2 board family, which consists of:
iMX8MN SMM S2 and iMX8MN SMM S2 PRO boards.

Add support for iMX8MN BSH SMM S2 board:

- 256 MiB DDR3 RAM
- 512MiB Nand
- USBOTG1 peripheral - fastboot.
- 100Mbit Ethernet

Add support for iMX8MN BSH SMM S2 PRO board:

- 512 MiB DDR3 RAM
- 8 GiB eMMC
- USBOTG1 peripheral - fastboot.
- 100Mbit Ethernet

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
diff --git a/board/bsh/imx8mn_smm_s2/spl.c b/board/bsh/imx8mn_smm_s2/spl.c
new file mode 100644
index 0000000..5f04731
--- /dev/null
+++ b/board/bsh/imx8mn_smm_s2/spl.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2021 Collabora Ltd.
+ *
+ */
+
+#include <hang.h>
+#include <init.h>
+#include <spl.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/ddr.h>
+#include <asm/arch/imx8mn_pins.h>
+#include <asm/arch/sys_proto.h>
+#include <asm/mach-imx/boot_mode.h>
+#include <asm/mach-imx/gpio.h>
+#include <dm/device.h>
+#include <dm/uclass.h>
+
+int spl_board_boot_device(enum boot_device boot_dev_spl)
+{
+	return BOOT_DEVICE_BOOTROM;
+}
+
+void spl_dram_init(void)
+{
+	ddr_init(&dram_timing);
+}
+
+void spl_board_init(void)
+{
+	struct udevice *dev;
+	int ret;
+
+	debug("Normal Boot\n");
+
+	ret = uclass_get_device_by_name(UCLASS_CLK,
+					"clock-controller@30380000",
+					&dev);
+	if (ret < 0)
+		puts("Failed to find clock node. Check device tree\n");
+}
+
+#define UART_PAD_CTRL	(PAD_CTL_DSE6 | PAD_CTL_FSEL1)
+#define WDOG_PAD_CTRL	(PAD_CTL_DSE6 | PAD_CTL_ODE | PAD_CTL_PUE | PAD_CTL_PE)
+
+static const iomux_v3_cfg_t uart_pads[] = {
+	IMX8MN_PAD_UART4_RXD__UART4_DCE_RX | MUX_PAD_CTRL(UART_PAD_CTRL),
+	IMX8MN_PAD_UART4_TXD__UART4_DCE_TX | MUX_PAD_CTRL(UART_PAD_CTRL),
+};
+
+static const iomux_v3_cfg_t wdog_pads[] = {
+	IMX8MN_PAD_GPIO1_IO02__WDOG1_WDOG_B | MUX_PAD_CTRL(WDOG_PAD_CTRL),
+};
+
+int board_early_init_f(void)
+{
+	struct wdog_regs *wdog = (struct wdog_regs *)WDOG1_BASE_ADDR;
+
+	imx_iomux_v3_setup_multiple_pads(wdog_pads, ARRAY_SIZE(wdog_pads));
+	set_wdog_reset(wdog);
+
+	imx_iomux_v3_setup_multiple_pads(uart_pads, ARRAY_SIZE(uart_pads));
+	init_uart_clk(3);
+
+	if (IS_ENABLED(CONFIG_NAND_MXS)) {
+		init_nand_clk();
+	}
+
+	return 0;
+}
+
+void board_init_f(ulong dummy)
+{
+	int ret;
+
+	/* Clear the BSS. */
+	memset(__bss_start, 0, __bss_end - __bss_start);
+
+	arch_cpu_init();
+
+	board_early_init_f();
+
+	timer_init();
+
+	preloader_console_init();
+
+	ret = spl_init();
+	if (ret) {
+		debug("spl_init() failed: %d\n", ret);
+		hang();
+	}
+
+	/* DDR initialization */
+	spl_dram_init();
+
+	board_init_r(NULL, 0);
+}