[PATCH] iMX31: Add support to iMX31PDK board boots from NAND Flash

[Alan Carvalho de Assis]

This patch adds support to iMX31PDK board to boot directly from NAND
Flash. In order to it works the previous patches (which reduces start.S
size and copy NAND code to RAM) need be applied first.

Signed-off-by: Alan Carvalho de Assis <alan.assis at freescale.com>
---
 board/freescale/mx31pdk/lowlevel_init.S |   95 +++++++++++++++++++++++++++++-
 board/freescale/mx31pdk/u-boot.lds      |    3 +
 include/configs/mx31pdk.h               |   16 ++++--
 3 files changed, 105 insertions(+), 9 deletions(-)

diff --git a/board/freescale/mx31pdk/lowlevel_init.S
b/board/freescale/mx31pdk/lowlevel_init.S
index a94ea7f..71ab612 100644
--- a/board/freescale/mx31pdk/lowlevel_init.S
+++ b/board/freescale/mx31pdk/lowlevel_init.S
@@ -20,11 +20,98 @@
  * MA 02111-1307 USA
  */

-/*
- * This is just to keep the linker happy.
- */
+#include <asm/arch/mx31-regs.h>
+
+.macro REG reg, val
+	ldr r2, =\reg
+	ldr r3, =\val
+	str r3, [r2]
+.endm
+
+.macro REG8 reg, val
+	ldr r2, =\reg
+	ldr r3, =\val
+	strb r3, [r2]
+.endm
+
+.macro DELAY loops
+	ldr r2, =\loops
+1:
+	subs	r2, r2, #1
+	nop
+	bcs 1b
+.endm

 .globl lowlevel_init
 lowlevel_init:
-	mov	pc, lr
+	/* Store return address on the stack since lr is re-used in this file */
+	/* and all other registers are re-used as well */
+	str lr, [sp]
+
+	/* Also setup the Peripheral Port Remap register inside the core */
+	ldr r0, =ARM_PPMRR        /* start from AIPS 2GB region */
+	mcr p15, 0, r0, c15, c2, 4
+
+	REG	IPU_CONF, IPU_CONF_DI_EN
+	REG	CCM_CCMR, 0x074B0BF5
+
+	DELAY 0x40000
+
+	REG	CCM_CCMR, 0x074B0BF5 | CCMR_MPE
+	REG	CCM_CCMR, (0x074B0BF5 | CCMR_MPE) & ~CCMR_MDS
+
+	/* Set up clock to 532MHz */
+	REG	CCM_PDR0, 0xFF871D58
+	REG	CCM_MPCTL, 0x0033280C
+	REG	CCM_SPCTL, PLL_PD(1) | PLL_MFD(4) | PLL_MFI(12) | PLL_MFN(1)
+
+	/* Set up CPLD on CS5 */
+	REG	CSCR_U(5), 0x0000D843
+	REG	CSCR_L(5), 0x22252521
+	REG	CSCR_A(5), 0x22220A00
+
+	/* Set up MX31 DDR Memory Controller */
+	REG	0x43FAC26C, 0 /* SDCLK */
+	REG	0x43FAC270, 0 /* CAS */
+	REG	0x43FAC274, 0 /* RAS */
+	REG	0x43FAC27C, 0x1000 /* CS2	CSD0) */
+	REG	0x43FAC284, 0 /* DQM3 */
+	REG	0x43FAC288, 0 /* DQM2, DQM1, DQM0, SD31-SD0, A25-A0, MA10	0x288..0x2DC) */
+	REG	0x43FAC28C, 0
+	REG	0x43FAC290, 0
+	REG	0x43FAC294, 0
+	REG	0x43FAC298, 0
+	REG	0x43FAC29C, 0
+	REG	0x43FAC2A0, 0
+	REG	0x43FAC2A4, 0
+	REG	0x43FAC2A8, 0
+	REG	0x43FAC2AC, 0
+	REG	0x43FAC2B0, 0
+	REG	0x43FAC2B4, 0
+	REG	0x43FAC2B8, 0
+	REG	0x43FAC2BC, 0
+	REG	0x43FAC2C0, 0
+	REG	0x43FAC2C4, 0
+	REG	0x43FAC2C8, 0
+	REG	0x43FAC2CC, 0
+	REG	0x43FAC2D0, 0
+	REG	0x43FAC2D4, 0
+	REG	0x43FAC2D8, 0
+	REG	0x43FAC2DC, 0
+	REG	0xB8001010, 0x00000004
+	REG	0xB8001004, 0x006ac73a
+	REG	0xB8001000, 0x92100000
+	REG	0x80000f00, 0x12344321
+	REG	0xB8001000, 0xa2100000
+	REG	0x80000000, 0x12344321
+	REG	0x80000000, 0x12344321
+	REG	0xB8001000, 0xb2100000
+	REG8	0x80000033, 0xda
+	REG8	0x81000000, 0xff
+	REG	0xB8001000, 0x82226080
+	REG	0x80000000, 0xDEADBEEF
+	REG	0xB8001010, 0x0000000c
+
+	/* Copy from NAND to RAM */
+	b nand_copy

diff --git a/board/freescale/mx31pdk/u-boot.lds
b/board/freescale/mx31pdk/u-boot.lds
index 1460adc..8602f3e 100644
--- a/board/freescale/mx31pdk/u-boot.lds
+++ b/board/freescale/mx31pdk/u-boot.lds
@@ -35,6 +35,9 @@ SECTIONS
 	.text	   :
 	{
 	  cpu/arm1136/start.o	(.text)
+	  board/freescale/mx31pdk/lowlevel_init.o	(.text)
+	  cpu/arm1136/mx31/nand_copy.o	(.text)
+	  . = 2K; /* lowlevel NAND needs to fit in 2KB of NFC buffer */
 	  *(.text)
 	}

diff --git a/include/configs/mx31pdk.h b/include/configs/mx31pdk.h
index 6df1a00..d4362e3 100644
--- a/include/configs/mx31pdk.h
+++ b/include/configs/mx31pdk.h
@@ -38,6 +38,9 @@
 #define CONFIG_MX31_HCLK_FREQ	26000000
 #define CONFIG_MX31_CLK32	32768

+/* We are booting from NAND. Used to shrink start.S */
+#define CONFIG_BOOT_FROM_NAND		1
+
 #define CONFIG_DISPLAY_CPUINFO
 #define CONFIG_DISPLAY_BOARDINFO

@@ -45,11 +48,6 @@
 #define CONFIG_SETUP_MEMORY_TAGS	1
 #define CONFIG_INITRD_TAG		1

-/* No support for NAND boot for i.MX31 PDK yet, so we rely on some other
- * program to initialize the SDRAM.
- */
-#define CONFIG_SKIP_LOWLEVEL_INIT
-
 /*
  * Size of malloc() pool
  */
@@ -132,6 +130,13 @@
 #define CONFIG_CMDLINE_EDITING	1

 /*-----------------------------------------------------------------------
+ * Early stack pointer
+ *
+ * Use internal SRAM memory as SP when booting from NAND (ie. to iMX NFC)
+ */
+#define CFG_INTERNAL_SRAM_STACK	0x1FFFFFF0
+
+/*-----------------------------------------------------------------------
  * Stack sizes
  *
  * The stack sizes are set up in start.S using the settings below
@@ -151,6 +156,7 @@
 /* No NOR flash present */
 #define CFG_NO_FLASH		1

+/* We can't save to Flash. Then place Environment nowhere */
 #define CFG_ENV_IS_NOWHERE	1

 #define CFG_ENV_SIZE		(128 * 1024)
-- 
1.5.4.3