haswell: add romstage_after_car() function

There are changes coming to perform more complex tasks after cache-as-ram
has been torn down but before ramstage is loaded. Therefore, add the
romstage_after_car() function to call after cache-as-ram is torn down.
Its responsibility is for loading the ramstage and any other complex
tasks. For example, the saving of OS-controlled memory in the resume
path has now been moved into C instead of assembly.

Change-Id: Ie0c229cf83a9271c8995b31c534c8e5a696b164e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2757
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/cpu/intel/haswell/cache_as_ram.inc

@@ -305,38 +305,10 @@ before_romstage:
 
 	post_code(0x3c)
 
-#if CONFIG_HAVE_ACPI_RESUME
-	movl	CBMEM_BOOT_MODE, %eax
-	cmpl	$0x2, %eax // Resume?
-	jne	__acpi_resume_backup_done
-
-	/* copy 1MB - 64K to high tables ram_base to prevent memory corruption
-	 * through stage 2. We could keep stuff like stack and heap in high
-	 * tables memory completely, but that's a wonderful clean up task for
-	 * another day.
-	 */
-	cld
-	movl	$CONFIG_RAMBASE, %esi
-	movl	CBMEM_RESUME_BACKUP, %edi
-	movl	$HIGH_MEMORY_SAVE / 4, %ecx
-	rep	movsl
-
-__acpi_resume_backup_done:
-#endif
-
-	post_code(0x3d)
-
-	/* Clear boot_complete flag. */
-	xorl	%ebp, %ebp
 __main:
 	post_code(POST_PREPARE_RAMSTAGE)
 	cld			/* Clear direction flag. */
-
-	movl	%ebp, %esi
-
-	movl	%esp, %ebp
-	pushl	%esi
-	call	copy_and_run
+	call	romstage_after_car
 
 .Lhlt:
 	post_code(POST_DEAD_CODE)

src/cpu/intel/haswell/haswell.h

@@ -129,6 +129,9 @@ void romstage_common(const struct romstage_params *params);
  *  ...
  */
 void * __attribute__((regparm(0))) romstage_main(unsigned long bist);
+/* romstage_after_car() is the C function called after cache-as-ram has
+ * been torn down. It is responsible for loading the ramstage. */
+void romstage_after_car(void);
 #endif
 
 #ifdef __SMM__

src/cpu/intel/haswell/romstage.c

@@ -18,6 +18,7 @@
  */
 
 #include <stdint.h>
+#include <string.h>
 #include <cbmem.h>
 #include <console/console.h>
 #include <arch/cpu.h>
@@ -28,6 +29,7 @@
 #include <lib.h>
 #include <timestamp.h>
 #include <arch/io.h>
+#include <arch/stages.h>
 #include <arch/romcc_io.h>
 #include <device/pci_def.h>
 #include <cpu/x86/lapic.h>
@@ -272,3 +274,22 @@ void romstage_common(const struct romstage_params *params)
 	timestamp_add_now(TS_END_ROMSTAGE);
 #endif
 }
+
+static inline void prepare_for_resume(void)
+{
+#if CONFIG_HAVE_ACPI_RESUME
+	/* Back up the OS-controlled memory where ramstage will be loaded. */
+	if (*(u32 *)CBMEM_BOOT_MODE == 2) {
+		void *src = (void *)CONFIG_RAMBASE;
+		void *dest = *(void **)CBMEM_RESUME_BACKUP;
+		memcpy(dest, src, HIGH_MEMORY_SAVE);
+	}
+#endif
+}
+
+void romstage_after_car(void)
+{
+	prepare_for_resume();
+	/* Load the ramstage. */
+	copy_and_run(0);
+}