OneNAND Initial Program Loader (IPL) support

This patch enables the OneNAND boot within U-Boot.
Before this work, we used another OneNAND IPL called X-Loader based
on open source. With this work, we can build the oneboot.bin image
without other program.

The build sequence is simple.
First, it compiles the u-boot.bin
Second, it compiles OneNAND IPL
Finally, it becomes the oneboot.bin from OneNAND IPL and u-boot.bin
The mechanism is similar with NAND boot except it boots from itself.

Another thing is that you can only use the OneNAND IPL only to work
other bootloader such as RedBoot and so on.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
diff --git a/cpu/arm1136/start.S b/cpu/arm1136/start.S
index 17c7a83..8b765f1 100644
--- a/cpu/arm1136/start.S
+++ b/cpu/arm1136/start.S
@@ -35,6 +35,25 @@
 #endif
 .globl _start
 _start: b	reset
+#ifdef CONFIG_ONENAND_IPL
+	ldr	pc, _hang
+	ldr	pc, _hang
+	ldr	pc, _hang
+	ldr	pc, _hang
+	ldr	pc, _hang
+	ldr	pc, _hang
+	ldr	pc, _hang
+
+_hang:
+	.word	do_hang
+	.word	0x12345678
+	.word	0x12345678
+	.word	0x12345678
+	.word	0x12345678
+	.word	0x12345678
+	.word	0x12345678
+	.word	0x12345678	/* now 16*4=64 */
+#else
 	ldr	pc, _undefined_instruction
 	ldr	pc, _software_interrupt
 	ldr	pc, _prefetch_abort
@@ -51,6 +70,7 @@
 _irq:			.word irq
 _fiq:			.word fiq
 _pad:			.word 0x12345678 /* now 16*4=64 */
+#endif	/* CONFIG_ONENAND_IPL */
 .global _end_vect
 _end_vect:
 
@@ -139,7 +159,9 @@
 	adr	r0, _start		/* r0 <- current position of code   */
 	ldr	r1, _TEXT_BASE		/* test if we run from flash or RAM */
 	cmp	r0, r1			/* don't reloc during debug	    */
+#ifndef CONFIG_ONENAND_IPL
 	beq	stack_setup
+#endif	/* CONFIG_ONENAND_IPL */
 
 	ldr	r2, _armboot_start
 	ldr	r3, _bss_start
@@ -156,26 +178,36 @@
 	/* Set up the stack						    */
 stack_setup:
 	ldr	r0, _TEXT_BASE		/* upper 128 KiB: relocated uboot   */
+#ifdef CONFIG_ONENAND_IPL
+	sub	sp, r0, #128		/* leave 32 words for abort-stack   */
+#else
 	sub	r0, r0, #CFG_MALLOC_LEN /* malloc area			    */
 	sub	r0, r0, #CFG_GBL_DATA_SIZE /* bdinfo			    */
 #ifdef CONFIG_USE_IRQ
 	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
 #endif
 	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
+#endif	/* CONFIG_ONENAND_IPL */
 
 clear_bss:
 	ldr	r0, _bss_start		/* find start of bss segment	    */
 	ldr	r1, _bss_end		/* stop here			    */
 	mov	r2, #0x00000000		/* clear			    */
 
+#ifndef CONFIG_ONENAND_IPL
 clbss_l:str	r2, [r0]		/* clear loop...		    */
 	add	r0, r0, #4
 	cmp	r0, r1
 	bne	clbss_l
+#endif
 
 	ldr	pc, _start_armboot
 
+#ifdef CONFIG_ONENAND_IPL
+_start_armboot: .word start_oneboot
+#else
 _start_armboot: .word start_armboot
+#endif
 
 
 /*
@@ -214,6 +246,8 @@
 	bl	lowlevel_init	/* go setup pll,mux,memory */
 	mov	lr, ip		/* restore link */
 	mov	pc, lr		/* back to my caller */
+
+#ifndef CONFIG_ONENAND_IPL
 /*
  *************************************************************************
  *
@@ -326,10 +360,17 @@
 	.macro get_fiq_stack			@ setup FIQ stack
 	ldr	sp, FIQ_STACK_START
 	.endm
+#endif	/* CONFIG_ONENAND_IPL */
 
 /*
  * exception handlers
  */
+#ifdef CONFIG_ONENAND_IPL
+	.align	5
+do_hang:
+	ldr	sp, _TEXT_BASE			/* use 32 words about stack */
+	bl	hang				/* hang and never return */
+#else	/* !CONFIG_ONENAND IPL */
 	.align	5
 undefined_instruction:
 	get_bad_stack
@@ -415,3 +456,4 @@
 	.word	PM_RSTCTRL_WKUP
 
 #endif
+#endif	/* CONFIG_ONENAND_IPL */