boot-from-ram-reloc.patch

来自「Uboot常用的移植patches, 方便定制移植到s3c2440」· PATCH 代码 · 共 63 行

This patch allows us to boot from anywhere in RAM. It mainly sets the stage
for later patches. The only real changes here is the better handling of already
cached code (e.g., if we were started by a previous instance of u-boot), and
that we drop CONFIG_SKIP_RELOCATE_UBOOT from neo1973.h

cpu/arm920t/start.S: if not relocating, instead of going straight to
  stack_setup, jump to done_relocate, which may perform other setup tasks
cpu/arm920t/start.S: after relocating, flush the cache and jump to the new code
include/configs/neo1973.h: remove CONFIG_SKIP_RELOCATE_UBOOT

- Werner Almesberger <[e-mail]>

Index: u-boot/cpu/arm920t/start.S
===================================================================
--- u-boot.orig/cpu/arm920t/start.S
+++ u-boot/cpu/arm920t/start.S
@@ -256,7 +256,7 @@
 	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         */
-	beq     stack_setup
+	beq     done_relocate
 
 	ldr	r2, _armboot_start
 	ldr	r3, _bss_start
@@ -266,8 +266,14 @@
 copy_loop:
 	ldmia	r0!, {r3-r10}		/* copy from source address [r0]    */
 	stmia	r1!, {r3-r10}		/* copy to   target address [r1]    */
-	cmp	r0, r2			/* until source end addreee [r2]    */
+	cmp	r0, r2			/* until source end address [r2]    */
 	ble	copy_loop
+	mov	r0, #0			/* flush v3/v4 cache */
+	mcr	p15, 0, r0, c7, c7, 0
+	ldr	pc, _done_relocate	/* jump to relocated code */
+_done_relocate:
+	.word	done_relocate
+done_relocate:
 #else /* NAND_BOOT */
 relocate:
 copy_myself:
@@ -355,7 +361,7 @@
 1:	b	1b
 done_nand_read:
 #endif /* NAND_BOOT */
-#endif	/* CONFIG_SKIP_RELOCATE_UBOOT */
+#endif /* CONFIG_SKIP_RELOCATE_UBOOT */
 #endif
 	/* Set up the stack						    */
 stack_setup:
Index: u-boot/include/configs/neo1973_gta01.h
===================================================================
--- u-boot.orig/include/configs/neo1973_gta01.h
+++ u-boot/include/configs/neo1973_gta01.h
@@ -28,7 +28,6 @@
 
 #if defined(BUILD_FOR_RAM)
 /* If we want to start u-boot from inside RAM */
-#define CONFIG_SKIP_RELOCATE_UBOOT	1
 #define CONFIG_SKIP_LOWLEVEL_INIT	1
 #else
 /* we want to start u-boot directly from within NAND flash */