soc/intel/common: remove mrc cache assumptions

Update the mrc cache implementation to use region_file. Instead
of relying on memory-mapped access and pointer arithmetic
use the region_devices and region_file to obtain the latest
data associated with the region. This removes the need for the
nvm wrapper as the region_devices can be used directly. Thus,
the library is more generic and can be extended to work on
different boot mediums.

BUG=chrome-os-partner:56151

Change-Id: Ic14e2d2f7339e50256b4a3a297fc33991861ca44
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/17717
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
diff --git a/src/soc/intel/baytrail/romstage/raminit.c b/src/soc/intel/baytrail/romstage/raminit.c
index a79fe95..190231d 100644
--- a/src/soc/intel/baytrail/romstage/raminit.c
+++ b/src/soc/intel/baytrail/romstage/raminit.c
@@ -15,7 +15,7 @@
 
 #include <stddef.h>
 #include <arch/acpi.h>
-#include <arch/io.h>
+#include <assert.h>
 #include <cbfs.h>
 #include <cbmem.h>
 #include <console/console.h>
@@ -111,7 +111,7 @@
 {
 	int ret;
 	mrc_wrapper_entry_t mrc_entry;
-	const struct mrc_saved_data *cache;
+	struct region_device rdev;
 
 	/* Fill in default entries. */
 	mp->version = MRC_PARAMS_VER;
@@ -125,9 +125,11 @@
 
 	if (vboot_recovery_mode_enabled()) {
 		printk(BIOS_DEBUG, "Recovery mode: not using MRC cache.\n");
-	} else if (!mrc_cache_get_current(&cache)) {
-		mp->saved_data_size = cache->size;
-		mp->saved_data = &cache->data[0];
+	} else if (!mrc_cache_get_current(MRC_TRAINING_DATA, 0, &rdev)) {
+		mp->saved_data_size = region_device_sz(&rdev);
+		mp->saved_data = rdev_mmap_full(&rdev);
+		/* Assume boot device is memory mapped. */
+		assert(IS_ENABLED(CONFIG_BOOT_DEVICE_MEMORY_MAPPED));
 	} else if (prev_sleep_state == ACPI_S3) {
 		/* If waking from S3 and no cache then. */
 		printk(BIOS_DEBUG, "No MRC cache found in S3 resume path.\n");
@@ -178,5 +180,6 @@
 	       mp->data_to_save_size);
 
 	if (mp->data_to_save != NULL && mp->data_to_save_size > 0)
-		mrc_cache_stash_data(mp->data_to_save, mp->data_to_save_size);
+		mrc_cache_stash_data(MRC_TRAINING_DATA, 0, mp->data_to_save,
+					mp->data_to_save_size);
 }