imx: mx6slevk: add SPL support

Add SPL boot support for mx6slevk board.
1. Introduce a configuration file mx6slevk_spl_defconfig.
2. i.MX6SL has same DRAM space with i.MX6SX, need to change SPL DRAM SPACE.
3. Include imx6_spl.h and related SPL macro in mx6slevk.h.
4. select SUPPORT_SPL for TARGET_MX6SLEVK.
5. Add SPL board code to do related initialization.

Boot Log:

U-Boot SPL 2015.07-00544-g1594a76 (Aug 17 2015 - 01:56:59)
reading u-boot.img
reading u-boot.img

U-Boot 2015.07-00544-g1594a76 (Aug 17 2015 - 01:56:59 +0000)

CPU:   Freescale i.MX6SL rev1.2 996 MHz (running at 396 MHz)
CPU:   Commercial temperature grade (0C to 95C) at 50C
Reset cause: POR
Board: MX6SLEVK
I2C:   ready
DRAM:  1 GiB
PMIC:  PFUZE100 ID=0x10
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   FEC [PRIME]
Hit any key to stop autoboot:  0

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/board/freescale/mx6slevk/mx6slevk.c b/board/freescale/mx6slevk/mx6slevk.c
index 98e3ef0..6ba604e 100644
--- a/board/freescale/mx6slevk/mx6slevk.c
+++ b/board/freescale/mx6slevk/mx6slevk.c
@@ -8,7 +8,9 @@
 
 #include <asm/arch/clock.h>
 #include <asm/arch/iomux.h>
+#include <asm/arch/crm_regs.h>
 #include <asm/arch/imx-regs.h>
+#include <asm/arch/mx6-ddr.h>
 #include <asm/arch/mx6-pins.h>
 #include <asm/arch/sys_proto.h>
 #include <asm/gpio.h>
@@ -190,6 +192,7 @@
 
 int board_mmc_init(bd_t *bis)
 {
+#ifndef CONFIG_SPL_BUILD
 	int i, ret;
 
 	/*
@@ -234,6 +237,44 @@
 	}
 
 	return 0;
+#else
+	struct src *src_regs = (struct src *)SRC_BASE_ADDR;
+	u32 val;
+	u32 port;
+
+	val = readl(&src_regs->sbmr1);
+
+	/* Boot from USDHC */
+	port = (val >> 11) & 0x3;
+	switch (port) {
+	case 0:
+		imx_iomux_v3_setup_multiple_pads(usdhc1_pads,
+						 ARRAY_SIZE(usdhc1_pads));
+		gpio_direction_input(USDHC1_CD_GPIO);
+		usdhc_cfg[0].esdhc_base = USDHC1_BASE_ADDR;
+		usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC_CLK);
+		break;
+	case 1:
+		imx_iomux_v3_setup_multiple_pads(usdhc2_pads,
+						 ARRAY_SIZE(usdhc2_pads));
+		gpio_direction_input(USDHC2_CD_GPIO);
+		usdhc_cfg[0].esdhc_base = USDHC2_BASE_ADDR;
+		usdhc_cfg[0].max_bus_width = 4;
+		usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC2_CLK);
+		break;
+	case 2:
+		imx_iomux_v3_setup_multiple_pads(usdhc3_pads,
+						 ARRAY_SIZE(usdhc3_pads));
+		gpio_direction_input(USDHC3_CD_GPIO);
+		usdhc_cfg[0].esdhc_base = USDHC3_BASE_ADDR;
+		usdhc_cfg[0].max_bus_width = 4;
+		usdhc_cfg[0].sdhc_clk = mxc_get_clock(MXC_ESDHC3_CLK);
+		break;
+	}
+
+	gd->arch.sdhc_clk = usdhc_cfg[0].sdhc_clk;
+	return fsl_esdhc_initialize(bis, &usdhc_cfg[0]);
+#endif
 }
 
 #ifdef CONFIG_SYS_I2C_MXC
@@ -361,3 +402,126 @@
 
 	return 0;
 }
+
+#ifdef CONFIG_SPL_BUILD
+#include <spl.h>
+#include <libfdt.h>
+
+const struct mx6sl_iomux_ddr_regs mx6_ddr_ioregs = {
+	.dram_sdqs0 = 0x00003030,
+	.dram_sdqs1 = 0x00003030,
+	.dram_sdqs2 = 0x00003030,
+	.dram_sdqs3 = 0x00003030,
+	.dram_dqm0 = 0x00000030,
+	.dram_dqm1 = 0x00000030,
+	.dram_dqm2 = 0x00000030,
+	.dram_dqm3 = 0x00000030,
+	.dram_cas  = 0x00000030,
+	.dram_ras  = 0x00000030,
+	.dram_sdclk_0 = 0x00000028,
+	.dram_reset = 0x00000030,
+	.dram_sdba2 = 0x00000000,
+	.dram_odt0 = 0x00000008,
+	.dram_odt1 = 0x00000008,
+};
+
+const struct mx6sl_iomux_grp_regs mx6_grp_ioregs = {
+	.grp_b0ds = 0x00000030,
+	.grp_b1ds = 0x00000030,
+	.grp_b2ds = 0x00000030,
+	.grp_b3ds = 0x00000030,
+	.grp_addds = 0x00000030,
+	.grp_ctlds = 0x00000030,
+	.grp_ddrmode_ctl = 0x00020000,
+	.grp_ddrpke = 0x00000000,
+	.grp_ddrmode = 0x00020000,
+	.grp_ddr_type = 0x00080000,
+};
+
+const struct mx6_mmdc_calibration mx6_mmcd_calib = {
+	.p0_mpdgctrl0 =  0x20000000,
+	.p0_mpdgctrl1 =  0x00000000,
+	.p0_mprddlctl =  0x4241444a,
+	.p0_mpwrdlctl =  0x3030312b,
+	.mpzqlp2ctl = 0x1b4700c7,
+};
+
+static struct mx6_lpddr2_cfg mem_ddr = {
+	.mem_speed = 800,
+	.density = 4,
+	.width = 32,
+	.banks = 8,
+	.rowaddr = 14,
+	.coladdr = 10,
+	.trcd_lp = 2000,
+	.trppb_lp = 2000,
+	.trpab_lp = 2250,
+	.trasmin = 4200,
+};
+
+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(0x00260324, &ccm->cbcmr);
+}
+
+static void spl_dram_init(void)
+{
+	struct mx6_ddr_sysinfo sysinfo = {
+		.dsize = mem_ddr.width / 32,
+		.cs_density = 20,
+		.ncs = 2,
+		.cs1_mirror = 0,
+		.walat = 0,
+		.ralat = 2,
+		.mif3_mode = 3,
+		.bi_on = 1,
+		.rtt_wr = 0,        /* LPDDR2 does not need rtt_wr rtt_nom */
+		.rtt_nom = 0,
+		.sde_to_rst = 0,    /* LPDDR2 does not need this field */
+		.rst_to_cke = 0x10, /* JEDEC value for LPDDR2: 200us */
+		.ddr_type = DDR_TYPE_LPDDR2,
+	};
+	mx6sl_dram_iocfg(32, &mx6_ddr_ioregs, &mx6_grp_ioregs);
+	mx6_dram_cfg(&sysinfo, &mx6_mmcd_calib, &mem_ddr);
+}
+
+void board_init_f(ulong dummy)
+{
+	/* setup AIPS and disable watchdog */
+	arch_cpu_init();
+
+	ccgr_init();
+
+	/* iomux and setup of i2c */
+	board_early_init_f();
+
+	/* setup GP timer */
+	timer_init();
+
+	/* 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);
+}
+
+void reset_cpu(ulong addr)
+{
+}
+#endif