This patch makes u-boot use the default environment is booting from NOR. That
way, we can be sure no contamination occurs from a possibly severely upset
NAND.

nor-default-env.patch:
- cpu/arm920t/start.S, common/env_common.c (env_relocate): new configuration
  option CFG_DEFAULT_ENV_IF_NOR to use the default environment (and not try to
  load it from NAND) if booting from NOR
- cpu/arm920t/start.S (booted_from_nor): set this flag if booting from NOR
- include/configs/neo1973_gta02.h: set CFG_DEFAULT_ENV_IF_NOR

Signed-off-by: Werner Almesberger <werner@openmoko.org>

Index: u-boot/common/env_common.c
===================================================================
--- u-boot.orig/common/env_common.c
+++ u-boot/common/env_common.c
@@ -34,6 +34,10 @@
 extern char *preboot_override;
 #endif
 
+#ifdef CFG_DEFAULT_ENV_IF_NOR
+extern unsigned char booted_from_nor;
+#endif
+
 DECLARE_GLOBAL_DATA_PTR;
 
 #ifdef CONFIG_AMIGAONEG3SE
@@ -257,6 +261,13 @@
 		gd->env_valid = 0;
 #endif
 
+#ifdef CFG_DEFAULT_ENV_IF_NOR
+	if (booted_from_nor && gd->env_valid) {
+		puts("NOR boot, using default environment\n\n");
+		gd->env_valid = 0;
+	}
+#endif
+
 	if (gd->env_valid == 0)
 		default_env();
 	else {
Index: u-boot/cpu/arm920t/start.S
===================================================================
--- u-boot.orig/cpu/arm920t/start.S
+++ u-boot/cpu/arm920t/start.S
@@ -99,6 +99,16 @@
 	.word	booted_from_nand
 #endif /* CONFIG_S3C2410_NAND_BOOT */
 
+#ifdef CFG_DEFAULT_ENV_IF_NOR
+.globl	booted_from_nor
+booted_from_nor:
+	.word	0
+_booted_from_nor:
+	.word	booted_from_nor
+_end_if_0:
+	.word	__bss_start-_start
+#endif /* CFG_DEFAULT_ENV_IF_NOR */
+
 _TEXT_BASE:
 	.word	TEXT_BASE
 
@@ -382,6 +392,15 @@
 	stmia	r1!, {r3-r10}		/* copy to   target address [r1]    */
 	cmp	r0, r2			/* until source end address [r2]    */
 	ble	copy_loop
+
+#ifdef CFG_DEFAULT_ENV_IF_NOR
+	ldr	r0, _end_if_0		/* are we booting from NOR ? */
+	cmp	r0, r2
+	ldreq	r0, _booted_from_nor	/* remember that we've booted from  */
+	moveq	r1, #1			/* NOR				    */
+	streqb	r1, [r0]
+#endif /* CFG_DEFAULT_ENV_IF_NOR */
+
 	mov	r0, #0			/* flush v3/v4 cache */
 	mcr	p15, 0, r0, c7, c7, 0
 	ldr	pc, _done_relocate	/* jump to relocated code */
Index: u-boot/include/configs/neo1973_gta02.h
===================================================================
--- u-boot.orig/include/configs/neo1973_gta02.h
+++ u-boot/include/configs/neo1973_gta02.h
@@ -206,6 +206,7 @@
  */
 
 #define	CFG_ENV_IS_IN_NAND	1
+#define	CFG_DEFAULT_ENV_IF_NOR
 #define CFG_ENV_SIZE		0x40000	/* 128k Total Size of Environment Sector */
 #define CFG_ENV_OFFSET_OOB	1	/* Location of ENV stored in block 0 OOB */
 #define	CFG_PREBOOT_OVERRIDE	1	/* allow preboot from memory */