imx: Add variscite DART-6UL Evaluation Kit

Port for the DART-6UL Evaluation Kit SBC. Based on the variscite
DART-6UL iMX6ULL SoM.

CPU:   Freescale i.MX6ULL rev1.1 900 MHz (running at 396 MHz)
CPU:   Commercial temperature grade (0C to 95C) at 43C
Reset cause: POR
Model: Variscite DART-6UL Evaluation Kit
Board: Variscite DART-6UL Evaluation Kit
DRAM:  512 MiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
In:    serial@02020000
Out:   serial@02020000
Err:   serial@02020000
Net:   FEC0

Working:
 - Eth0
 - i2c
 - MMC/SD
 - eMMC
 - USB host
 - UART 1

Note: LCDIF porting needs DM_VIDEO
https://lists.denx.de/pipermail/u-boot/2019-April/365506.html

Signed-off-by: Parthiban Nallathambi <parthitce@gmail.com>
diff --git a/board/variscite/dart_6ul/spl.c b/board/variscite/dart_6ul/spl.c
new file mode 100644
index 0000000..f7e6ab6
--- /dev/null
+++ b/board/variscite/dart_6ul/spl.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2015-2019 Variscite Ltd.
+ * Copyright (C) 2019 Parthiban Nallathambi <parthitce@gmail.com>
+ */
+
+#include <common.h>
+#include <spl.h>
+#include <asm/arch/clock.h>
+#include <asm/io.h>
+#include <asm/arch/mx6-ddr.h>
+#include <asm/arch/mx6-pins.h>
+#include <asm/arch/crm_regs.h>
+#include <fsl_esdhc.h>
+
+#define UART_PAD_CTRL  (PAD_CTL_PKE | PAD_CTL_PUE |		\
+	PAD_CTL_PUS_100K_UP | PAD_CTL_SPEED_MED |		\
+	PAD_CTL_DSE_40ohm   | PAD_CTL_SRE_FAST  | PAD_CTL_HYS)
+
+static iomux_v3_cfg_t const uart1_pads[] = {
+	MX6_PAD_UART1_TX_DATA__UART1_DCE_TX | MUX_PAD_CTRL(UART_PAD_CTRL),
+	MX6_PAD_UART1_RX_DATA__UART1_DCE_RX | MUX_PAD_CTRL(UART_PAD_CTRL),
+};
+
+static void setup_iomux_uart(void)
+{
+	imx_iomux_v3_setup_multiple_pads(uart1_pads, ARRAY_SIZE(uart1_pads));
+}
+
+static struct mx6ul_iomux_grp_regs mx6_grp_ioregs = {
+	.grp_addds = 0x00000030,
+	.grp_ddrmode_ctl = 0x00020000,
+	.grp_b0ds = 0x00000030,
+	.grp_ctlds = 0x00000030,
+	.grp_b1ds = 0x00000030,
+	.grp_ddrpke = 0x00000000,
+	.grp_ddrmode = 0x00020000,
+	.grp_ddr_type = 0x000c0000,
+};
+
+static struct mx6ul_iomux_ddr_regs mx6_ddr_ioregs = {
+	.dram_dqm0 = 0x00000030,
+	.dram_dqm1 = 0x00000030,
+	.dram_ras = 0x00000030,
+	.dram_cas = 0x00000030,
+	.dram_odt0 = 0x00000030,
+	.dram_odt1 = 0x00000030,
+	.dram_sdba2 = 0x00000000,
+	.dram_sdclk_0 = 0x00000008,
+	.dram_sdqs0 = 0x00000038,
+	.dram_sdqs1 = 0x00000030,
+	.dram_reset = 0x00000030,
+};
+
+static struct mx6_mmdc_calibration mx6_mmcd_calib = {
+	.p0_mpwldectrl0 = 0x00000000,
+	.p0_mpdgctrl0   = 0x414C0158,
+	.p0_mprddlctl   = 0x40403A3A,
+	.p0_mpwrdlctl   = 0x40405A56,
+};
+
+struct mx6_ddr_sysinfo ddr_sysinfo = {
+	.dsize = 0,
+	.cs_density = 20,
+	.ncs = 1,
+	.cs1_mirror = 0,
+	.rtt_wr = 2,
+	.rtt_nom = 1,		/* RTT_Nom = RZQ/2 */
+	.walat = 1,		/* Write additional latency */
+	.ralat = 5,		/* Read additional latency */
+	.mif3_mode = 3,		/* Command prediction working mode */
+	.bi_on = 1,		/* Bank interleaving enabled */
+	.sde_to_rst = 0x10,	/* 14 cycles, 200us (JEDEC default) */
+	.rst_to_cke = 0x23,	/* 33 cycles, 500us (JEDEC default) */
+};
+
+static struct mx6_ddr3_cfg mem_ddr = {
+	.mem_speed = 800,
+	.density = 4,
+	.width = 16,
+	.banks = 8,
+	.rowaddr = 15,
+	.coladdr = 10,
+	.pagesz = 2,
+	.trcd = 1375,
+	.trcmin = 4875,
+	.trasmin = 3500,
+};
+
+static void ccgr_init(void)
+{
+	struct mxc_ccm_reg *ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	writel(0xFFFFFFFF, &ccm->CCGR0);
+	writel(0xFFFFFFFF, &ccm->CCGR1);
+	writel(0xFFFFFFFF, &ccm->CCGR2);
+	writel(0xFFFFFFFF, &ccm->CCGR3);
+	writel(0xFFFFFFFF, &ccm->CCGR4);
+	writel(0xFFFFFFFF, &ccm->CCGR5);
+	writel(0xFFFFFFFF, &ccm->CCGR6);
+	writel(0xFFFFFFFF, &ccm->CCGR7);
+	/* Enable Audio Clock for SOM codec */
+	writel(0x01130100, (long *)CCM_CCOSR);
+}
+
+static void spl_dram_init(void)
+{
+	mx6ul_dram_iocfg(mem_ddr.width, &mx6_ddr_ioregs, &mx6_grp_ioregs);
+	mx6_dram_cfg(&ddr_sysinfo, &mx6_mmcd_calib, &mem_ddr);
+}
+
+#define USDHC_PAD_CTRL (PAD_CTL_PKE | PAD_CTL_PUE |		\
+	PAD_CTL_PUS_22K_UP  | PAD_CTL_SPEED_LOW |		\
+	PAD_CTL_DSE_80ohm   | PAD_CTL_SRE_FAST  | PAD_CTL_HYS)
+static iomux_v3_cfg_t const usdhc1_pads[] = {
+	MX6_PAD_SD1_CLK__USDHC1_CLK | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_SD1_CMD__USDHC1_CMD | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_SD1_DATA0__USDHC1_DATA0 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_SD1_DATA1__USDHC1_DATA1 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_SD1_DATA2__USDHC1_DATA2 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_SD1_DATA3__USDHC1_DATA3 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+};
+
+#ifndef CONFIG_NAND_MXS
+static iomux_v3_cfg_t const usdhc2_pads[] = {
+	MX6_PAD_NAND_RE_B__USDHC2_CLK | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_WE_B__USDHC2_CMD | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA00__USDHC2_DATA0 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA01__USDHC2_DATA1 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA02__USDHC2_DATA2 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA03__USDHC2_DATA3 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA04__USDHC2_DATA4 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA05__USDHC2_DATA5 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA06__USDHC2_DATA6 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+	MX6_PAD_NAND_DATA07__USDHC2_DATA7 | MUX_PAD_CTRL(USDHC_PAD_CTRL),
+};
+#endif
+
+static struct fsl_esdhc_cfg usdhc_cfg[] = {
+	{
+		.esdhc_base = USDHC1_BASE_ADDR,
+		.max_bus_width = 4,
+	},
+#ifndef CONFIG_NAND_MXS
+	{
+		.esdhc_base = USDHC2_BASE_ADDR,
+		.max_bus_width = 8,
+	},
+#endif
+};
+
+int board_mmc_getcd(struct mmc *mmc)
+{
+	return 1;
+}
+
+int board_mmc_init(bd_t *bis)
+{
+	int i, ret;
+
+	for (i = 0; i < CONFIG_SYS_FSL_USDHC_NUM; i++) {
+		switch (i) {
+		case 0:
+			SETUP_IOMUX_PADS(usdhc1_pads);
+			usdhc_cfg[i].sdhc_clk = mxc_get_clock(MXC_ESDHC_CLK);
+			break;
+#ifndef CONFIG_NAND_MXS
+		case 1:
+			SETUP_IOMUX_PADS(usdhc2_pads);
+			usdhc_cfg[i].sdhc_clk = mxc_get_clock(MXC_ESDHC2_CLK);
+			break;
+#endif
+		default:
+			printf("Warning - USDHC%d controller not supporting\n",
+			       i + 1);
+			return 0;
+		}
+
+		ret = fsl_esdhc_initialize(bis, &usdhc_cfg[i]);
+		if (ret) {
+			printf("Warning: failed to initialize mmc dev %d\n", i);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+void board_init_f(ulong dummy)
+{
+	/* setup AIPS and disable watchdog */
+	arch_cpu_init();
+
+	ccgr_init();
+
+	/* setup GP timer */
+	timer_init();
+
+	setup_iomux_uart();
+
+	/* iomux and setup of i2c */
+	board_early_init_f();
+
+	/* UART clocks enabled and gd valid - init serial console */
+	preloader_console_init();
+
+	/* DDR initialization */
+	spl_dram_init();
+
+	/* Clear the BSS. */
+	memset(__bss_start, 0, __bss_end - __bss_start);
+
+	/* load/boot image from boot device */
+	board_init_r(NULL, 0);
+}