ARM: imx6ul: Add support for liteSOM

liteSOM is a System On Module (http://grinn-global.com/litesom/). It
can't exists on its own, but will be used as part of other boards.

Hardware specification:
 * NXP i.MX6UL processor
 * 256M or 512M DDR3 memory
 * optional eMMC (uSDHC2)

Here we treat SOM similar to SOC, so we place it inside arch/arm/mach-*
directory and make it possible to reuse initialization code (i.e. DDR,
eMMC init) for all boards that use it.

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>

arch/arm/Kconfig

@@ -900,6 +900,8 @@ source "arch/arm/mach-keystone/Kconfig"
 
 source "arch/arm/mach-kirkwood/Kconfig"
 
+source "arch/arm/mach-litesom/Kconfig"
+
 source "arch/arm/mach-mvebu/Kconfig"
 
 source "arch/arm/cpu/armv7/ls102xa/Kconfig"

arch/arm/Makefile

@@ -58,6 +58,7 @@ machine-$(CONFIG_ARCH_HIGHBANK)		+= highbank
 machine-$(CONFIG_ARCH_KEYSTONE)		+= keystone
 # TODO: rename CONFIG_KIRKWOOD -> CONFIG_ARCH_KIRKWOOD
 machine-$(CONFIG_KIRKWOOD)		+= kirkwood
+machine-$(CONFIG_LITESOM)		+= litesom
 machine-$(CONFIG_ARCH_MESON)		+= meson
 machine-$(CONFIG_ARCH_MVEBU)		+= mvebu
 # TODO: rename CONFIG_TEGRA -> CONFIG_ARCH_TEGRA

arch/arm/mach-litesom/Kconfig

@@ -0,0 +1,6 @@
+config LITESOM
+	bool
+	select MX6UL
+	select DM
+	select DM_THERMAL
+	select SUPPORT_SPL

arch/arm/mach-litesom/Makefile

@@ -0,0 +1,6 @@
+# (C) Copyright 2016 Grinn
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y  := litesom.o

arch/arm/mach-litesom/include/mach/litesom.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) 2016 Grinn
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __ARCH_ARM_MACH_LITESOM_SOM_H__
+#define __ARCH_ARM_MACH_LITESOM_SOM_H__
+
+int litesom_mmc_init(bd_t *bis);
+
+#ifdef CONFIG_SPL_BUILD
+void litesom_init_f(void);
+#endif
+
+#endif

arch/arm/mach-litesom/litesom.c

@@ -0,0 +1,200 @@
+/*
+ * Copyright (C) 2015-2016 Freescale Semiconductor, Inc.
+ * Copyright (C) 2016 Grinn
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <asm/arch/clock.h>
+#include <asm/arch/iomux.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/crm_regs.h>
+#include <asm/arch/mx6ul_pins.h>
+#include <asm/arch/mx6-pins.h>
+#include <asm/arch/sys_proto.h>
+#include <asm/gpio.h>
+#include <asm/imx-common/iomux-v3.h>
+#include <asm/imx-common/boot_mode.h>
+#include <asm/io.h>
+#include <common.h>
+#include <fsl_esdhc.h>
+#include <linux/sizes.h>
+#include <mmc.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#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)
+
+int dram_init(void)
+{
+	gd->ram_size = imx_ddr_size();
+
+	return 0;
+}
+
+static iomux_v3_cfg_t const emmc_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),
+
+	/* RST_B */
+	MX6_PAD_NAND_ALE__GPIO4_IO10 | MUX_PAD_CTRL(NO_PAD_CTRL),
+};
+
+#ifdef CONFIG_FSL_ESDHC
+static struct fsl_esdhc_cfg emmc_cfg = {USDHC2_BASE_ADDR, 0, 8};
+
+#define EMMC_PWR_GPIO	IMX_GPIO_NR(4, 10)
+
+int litesom_mmc_init(bd_t *bis)
+{
+	int ret;
+
+	/* eMMC */
+	imx_iomux_v3_setup_multiple_pads(emmc_pads, ARRAY_SIZE(emmc_pads));
+	gpio_direction_output(EMMC_PWR_GPIO, 0);
+	udelay(500);
+	gpio_direction_output(EMMC_PWR_GPIO, 1);
+	emmc_cfg.sdhc_clk = mxc_get_clock(MXC_ESDHC2_CLK);
+
+	ret = fsl_esdhc_initialize(bis, &emmc_cfg);
+	if (ret) {
+		printf("Warning: failed to initialize mmc dev 1 (eMMC)\n");
+		return ret;
+	}
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_SPL_BUILD
+#include <libfdt.h>
+#include <spl.h>
+#include <asm/arch/mx6-ddr.h>
+
+
+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 = 0x00000030,
+	.dram_sdqs0 = 0x00000030,
+	.dram_sdqs1 = 0x00000030,
+	.dram_reset = 0x00000030,
+};
+
+static struct mx6_mmdc_calibration mx6_mmcd_calib = {
+	.p0_mpwldectrl0 = 0x00000000,
+	.p0_mpdgctrl0 = 0x41570155,
+	.p0_mprddlctl = 0x4040474A,
+	.p0_mpwrdlctl = 0x40405550,
+};
+
+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 = 0,		/* 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) */
+	.ddr_type = DDR_TYPE_DDR3,
+	.refsel = 0,		/* Refresh cycles at 64KHz */
+	.refr = 1,		/* 2 refresh commands per refresh cycle */
+};
+
+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);
+}
+
+static void spl_dram_init(void)
+{
+	unsigned long ram_size;
+
+	mx6ul_dram_iocfg(mem_ddr.width, &mx6_ddr_ioregs, &mx6_grp_ioregs);
+	mx6_dram_cfg(&ddr_sysinfo, &mx6_mmcd_calib, &mem_ddr);
+
+	/*
+	 * Get actual RAM size, so we can adjust DDR row size for <512M
+	 * memories
+	 */
+	ram_size = get_ram_size((void *)CONFIG_SYS_SDRAM_BASE, SZ_512M);
+	if (ram_size < SZ_512M) {
+		mem_ddr.rowaddr = 14;
+		mx6_dram_cfg(&ddr_sysinfo, &mx6_mmcd_calib, &mem_ddr);
+	}
+}
+
+void litesom_init_f(void)
+{
+	ccgr_init();
+
+	/* setup AIPS and disable watchdog */
+	arch_cpu_init();
+
+#ifdef CONFIG_BOARD_EARLY_INIT_F
+	board_early_init_f();
+#endif
+
+	/* setup GP timer */
+	timer_init();
+
+	/* UART clocks enabled and gd valid - init serial console */
+	preloader_console_init();
+
+	/* DDR initialization */
+	spl_dram_init();
+}
+#endif