[GSoC] [ARM] Patch by Johannes Wischert.

Turn off interrupts at loader entryn and make sure the mmu is disabled.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32405 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/boot/platform/u-boot/arch/arm/shell.S

@@ -36,7 +36,31 @@ SYMBOL_END(_start_netbsd)
 SYMBOL(_start_common):
 	strb	r4,gUBootOS
 	str	r8,gUBootGlobalData
-	/* ... */
+
+	/*
+	 * Turn off interrupts and make sure we are in SVC mode
+	 */
+
+	mrs	r4, cpsr
+	bic	r4, r4, #0x1f
+	orr	r4, r4, #0xd3
+	msr	cpsr, r4
+
+	/*
+	 * Turn off MMU and data cache if necessary.
+	 * WARNING: assumes we are running with a 1-1 mapping if MMU is enabled.
+	 */
+	mrc	p15, 0, r4, c1, c0, 0
+	bic	r4, r4, #0x0000000f		     // WCAM bits
+	bic	r4, r4, #0x00000300		     // RS   bits
+	mcr	p15, 0, r4, c1, c0, 0
+	mov	r4, #0
+	mov	r4, r4
+	mov	r4, r4
+
+
+
+
 	ldrb	r4,gUBootOS
 	cmp	r4,#0
 	beq	start_raw