intel/i945: Use romstage_handoff for S3

Don't use scratchpad registers when we have romstage_handoff
to pass S3 resume flag. Scratchpad register was read too
late in ramstage so acpi_is_wakeup_s3() did not evaluate
correctly.

This fixes low memory corruption at 0x1000-0x102c and the lack
of coreboot tables (util/cbmem not working) after S3 resume.

This also fixes console log from reporting early in ramstage
"Normal boot" while on "S3 resume" path.

Change-Id: I2922a15a90d2f8272c3482579bdd96f8f33e9705
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/17675
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/southbridge/intel/i82801gx/i82801gx.h

@@ -375,7 +375,5 @@ int southbridge_detect_s3_resume(void);
 #define SS_CNT		0x50
 #define C3_RES		0x54
 
-#define SKPAD_ACPI_S3_MAGIC	0xcafed00d
-#define SKPAD_NORMAL_BOOT_MAGIC	0xcafebabe
 #endif /* __ACPI__ */
 #endif				/* SOUTHBRIDGE_INTEL_I82801GX_I82801GX_H */

src/southbridge/intel/i82801gx/smi.c

@@ -19,6 +19,7 @@
 #include <device/pci.h>
 #include <console/console.h>
 #include <arch/io.h>
+#include <arch/acpi.h>
 #include <cpu/cpu.h>
 #include <cpu/x86/cache.h>
 #include <cpu/x86/smm.h>
@@ -313,16 +314,6 @@ static void smm_relocate(void)
 
 static int smm_handler_copied = 0;
 
-static int is_wakeup(void)
-{
-	device_t dev0 = dev_find_slot(0, PCI_DEVFN(0,0));
-
-	if (!dev0)
-		return 0;
-
-	return pci_read_config32(dev0, 0xdc) == SKPAD_ACPI_S3_MAGIC;
-}
-
 static void smm_install(void)
 {
 	/* The first CPU running this gets to copy the SMM handler. But not all
@@ -336,7 +327,7 @@ static void smm_install(void)
 	/* if we're resuming from S3, the SMM code is already in place,
 	 * so don't copy it again to keep the current SMM state */
 
-	if (!is_wakeup()) {
+	if (!acpi_is_wakeup_s3()) {
 		/* enable the SMM memory window */
 		pci_write_config8(dev_find_slot(0, PCI_DEVFN(0, 0)), SMRAM,
 					D_OPEN | G_SMRAME | C_BASE_SEG);