bootutil: add swap without scratch strategy
This implements a swap upgrade that does not use a scratch area. It
works by first moving all sectors in the primary slot up one position,
and then looping on moving sector of index X of the secondary slot to
index X of the primary slot, followed by moving sector X+1 of the
primary slot to X on the secondary slot, for each sector X.
The idea behind this implementation was initially suggested by Jehudi
Maes (@Laczen) and implemented on his own bootloader (ZEPboot).
Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/boot/bootutil/src/swap_scratch.c b/boot/bootutil/src/swap_scratch.c
index bf638bf..588bd28 100644
--- a/boot/bootutil/src/swap_scratch.c
+++ b/boot/bootutil/src/swap_scratch.c
@@ -29,7 +29,7 @@
MCUBOOT_LOG_MODULE_DECLARE(mcuboot);
-#if MCUBOOT_SWAP_USING_SCRATCH
+#if !defined(MCUBOOT_SWAP_USING_MOVE)
#if defined(MCUBOOT_VALIDATE_PRIMARY_SLOT)
/*
@@ -175,7 +175,9 @@
size_t num_sectors_secondary;
size_t sz0, sz1;
size_t primary_slot_sz, secondary_slot_sz;
+#ifndef MCUBOOT_OVERWRITE_ONLY
size_t scratch_sz;
+#endif
size_t i, j;
int8_t smaller;
@@ -187,7 +189,9 @@
return 0;
}
+#ifndef MCUBOOT_OVERWRITE_ONLY
scratch_sz = boot_scratch_area_size(state);
+#endif
/*
* The following loop scans all sectors in a linear fashion, assuring that
@@ -228,6 +232,7 @@
smaller = 2;
j++;
}
+#ifndef MCUBOOT_OVERWRITE_ONLY
if (sz0 == sz1) {
primary_slot_sz += sz0;
secondary_slot_sz += sz1;
@@ -240,6 +245,7 @@
}
smaller = sz0 = sz1 = 0;
}
+#endif
}
if ((i != num_sectors_primary) ||
@@ -412,6 +418,7 @@
return BOOT_STATUS_SOURCE_NONE;
}
+#ifndef MCUBOOT_OVERWRITE_ONLY
/**
* Calculates the number of sectors the scratch area can contain. A "last"
* source sector is specified because images are copied backwards in flash
@@ -710,5 +717,6 @@
}
}
+#endif
#endif