cygnus: enable mmu

this is not only for speed but also preventing the cpu from crashing.
the cpu is not happy when cache is cleaned without mmu turned on.

BUG=chrome-os-partner:36691
BRANCH=broadcom-firmware
TEST=boot purin to romstage.

Change-Id: I2445dcc2729798c4fc56fa191cbc8471ef708d08
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 9e35c925b75213e1d35bf191f22c39aaf1726eeb
Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Change-Id: Icaf8c506df258edb99413949e6e3089a2b1a91af
Original-Reviewed-on: https://chrome-internal-review.googlesource.com/199388
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Daisuke Nojiri <dnojiri@google.com>
Original-Tested-by: Daisuke Nojiri <dnojiri@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/251306
Reviewed-on: http://review.coreboot.org/9768
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <edward.ocallaghan@koparo.com>
diff --git a/src/soc/broadcom/cygnus/bootblock.c b/src/soc/broadcom/cygnus/bootblock.c
index 37edf7f..3c6d242 100644
--- a/src/soc/broadcom/cygnus/bootblock.c
+++ b/src/soc/broadcom/cygnus/bootblock.c
@@ -17,13 +17,20 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <arch/cache.h>
 #include <bootblock_common.h>
-#include <console/console.h>
+#include <stddef.h>
+#include <symbols.h>
 
 void bootblock_soc_init(void)
 {
 	/*
-	 * typically, this is the place where mmu is initialized to enable
-	 * cache. it helps speed up vboot verification.
+	 * not only for speed but for preventing the cpu from crashing.
+	 * the cpu is not happy when cache is cleaned without mmu turned on.
 	 */
+	mmu_init();
+	mmu_config_range(0, 4096, DCACHE_OFF);
+	mmu_config_range_kb((uintptr_t)_sram/KiB, _sram_size/KiB,
+			    DCACHE_WRITETHROUGH);
+	dcache_mmu_enable();
 }