Calculate the hash only of the actual RW code

No need to hash a bunch of 0xff's at the end.  We explicitly set a
0xea byte after the end of the code in firmware_image.lds.S.

BUG=chrome-os-partner:11087
TEST=look for the hash start line in the EC debug output:

   [0.011543 hash start 0x00014000 0x00011590]

The second number is the code size.  It should be the same size as
ec.RW.bin, instead of 0x14000.

Change-Id: Ibc94851dc1a09eb46cad46bb97dc5762f9c521f0
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/28300

1 files changed, 12 insertions, 1 deletions

diff --git a/include/system.h b/include/system.h
index 4bcde16aae..d1975c9fed 100644
--- a/include/system.h
+++ b/include/system.h
@@ -104,12 +104,23 @@ const uint8_t *system_get_jump_tag(uint16_t tag, int *version, int *size);
 /* Return the address just past the last usable byte in RAM. */
 int system_usable_ram_end(void);
 
-/* Returns true if the given range is overlapped with the active image. */
+/* Return true if the given range is overlapped with the active image. */
 int system_unsafe_to_overwrite(uint32_t offset, uint32_t size);
 
 /* Return a text description of the image copy which is currently running. */
 const char *system_get_image_copy_string(void);
 
+/**
+ * Return the number of bytes used in the specified image.
+ *
+ * This is the actual size of code+data in the image, as opposed to the
+ * amount of space reserved in flash for that image.
+ *
+ * @return actual image size in bytes, 0 if the image contains no content or
+ * error.
+ */
+int system_get_image_used(enum system_image_copy_t copy);
+
 /* Jump to the specified image copy. */
 int system_run_image_copy(enum system_image_copy_t copy);