board: gateworks: venice: add imx8mn-gw7902 support

The GW7902 is based on the i.MX 8M Mini / Nano SoC featuring:
 - LPDDR4 DRAM
 - eMMC FLASH
 - Gateworks System Controller
 - LTE CAT M1 modem
 - USB 2.0 HUB
 - M.2 Socket with USB2.0, PCIe, and dual-SIM
 - IMX8M FEC
 - PCIe based GbE
 - RS232/RS485/RS422 serial transceiver
 - GPS
 - CAN bus
 - WiFi / Bluetooth
 - MIPI header (DSI/CSI/GPIO/PWM/I2S)
 - PMIC

To add support for the i.MX8M Nano GW7902:
 - Add imx8mn-venice dts/defconfig/include
 - Add imx8mn-gw7902 dts
 - Add imx8mn-2gb lpddr4 dram configs
 - Add misc support for IMX8M Nano SoC
 - rename imx8mm-venice.c to venice.c as it is no longer imx8mm specific
 - update README with differences for IMX8MN vs IMX8MM

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>

include/configs/imx8mn_venice.h

@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2022 Gateworks Corporation
+ */
+
+#ifndef __IMX8MM_VENICE_H
+#define __IMX8MM_VENICE_H
+
+#include <asm/arch/imx-regs.h>
+#include <linux/sizes.h>
+
+#define CONFIG_SPL_MAX_SIZE		(148 * 1024)
+#define CONFIG_SYS_MONITOR_LEN		SZ_512K
+#define CONFIG_SYS_UBOOT_BASE	\
+	(QSPI0_AMBA_BASE + CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512)
+
+#ifdef CONFIG_SPL_BUILD
+#define CONFIG_SPL_STACK		0x980000
+#define CONFIG_SPL_BSS_START_ADDR	0x950000
+#define CONFIG_SPL_BSS_MAX_SIZE		SZ_8K	/* 8 KB */
+#define CONFIG_SYS_SPL_MALLOC_START	0x42200000
+#define CONFIG_SYS_SPL_MALLOC_SIZE	SZ_512K	/* 512 KB */
+
+/* For RAW image gives a error info not panic */
+#define CONFIG_SPL_ABORT_ON_RAW_IMAGE
+#endif
+
+#define MEM_LAYOUT_ENV_SETTINGS \
+	"fdt_addr_r=0x44000000\0" \
+	"kernel_addr_r=0x42000000\0" \
+	"ramdisk_addr_r=0x46400000\0" \
+	"scriptaddr=0x46000000\0"
+
+/* Enable Distro Boot */
+#ifndef CONFIG_SPL_BUILD
+#define BOOT_TARGET_DEVICES(func) \
+	func(MMC, mmc, 1) \
+	func(MMC, mmc, 2) \
+	func(DHCP, dhcp, na)
+#include <config_distro_bootcmd.h>
+#undef CONFIG_ISO_PARTITION
+#else
+#define BOOTENV
+#endif
+
+/* Initial environment variables */
+#define CONFIG_EXTRA_ENV_SETTINGS \
+	BOOTENV \
+	MEM_LAYOUT_ENV_SETTINGS \
+	"script=boot.scr\0" \
+	"bootm_size=0x10000000\0" \
+	"dev=2\0" \
+	"preboot=gsc wd-disable\0" \
+	"console=ttymxc1,115200\0" \
+	"update_firmware=" \
+		"tftpboot $loadaddr $image && " \
+		"setexpr blkcnt $filesize + 0x1ff && " \
+		"setexpr blkcnt $blkcnt / 0x200 && " \
+		"mmc dev $dev && " \
+		"mmc write $loadaddr 0x40 $blkcnt\0" \
+	"boot_net=" \
+		"tftpboot $kernel_addr_r $image && " \
+		"booti $kernel_addr_r - $fdtcontroladdr\0" \
+	"update_rootfs=" \
+		"tftpboot $loadaddr $image && " \
+		"gzwrite mmc $dev $loadaddr $filesize 100000 1000000\0" \
+	"update_all=" \
+		"tftpboot $loadaddr $image && " \
+		"gzwrite mmc $dev $loadaddr $filesize\0" \
+	"erase_env=mmc dev $dev; mmc erase 0x7f08 0x40\0"
+
+#define CONFIG_SYS_INIT_RAM_ADDR        0x40000000
+#define CONFIG_SYS_INIT_RAM_SIZE        SZ_2M
+#define CONFIG_SYS_INIT_SP_OFFSET \
+	(CONFIG_SYS_INIT_RAM_SIZE - GENERATED_GBL_DATA_SIZE)
+#define CONFIG_SYS_INIT_SP_ADDR \
+	(CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_INIT_SP_OFFSET)
+
+#define CONFIG_SYS_SDRAM_BASE           0x40000000
+
+/* SDRAM configuration */
+#define PHYS_SDRAM                      0x40000000
+#define PHYS_SDRAM_SIZE			SZ_1G
+#define CONFIG_SYS_BOOTM_LEN		SZ_256M
+
+/* UART */
+#define CONFIG_MXC_UART_BASE		UART2_BASE_ADDR
+
+/* Monitor Command Prompt */
+#define CONFIG_SYS_CBSIZE		SZ_2K
+#define CONFIG_SYS_MAXARGS		64
+#define CONFIG_SYS_BARGSIZE		CONFIG_SYS_CBSIZE
+#define CONFIG_SYS_PBSIZE		(CONFIG_SYS_CBSIZE + \
+					sizeof(CONFIG_SYS_PROMPT) + 16)
+/* USDHC */
+#define CONFIG_SYS_FSL_USDHC_NUM	2
+#define CONFIG_SYS_FSL_ESDHC_ADDR	0
+
+/* FEC */
+#define CONFIG_ETHPRIME                 "eth0"
+#define CONFIG_FEC_XCV_TYPE             RGMII
+#define CONFIG_FEC_MXC_PHYADDR          0
+#define FEC_QUIRK_ENET_MAC
+
+#endif