ARM: make ARM_USE_COMPRESSED_DTB available for other arches

Other PBL-enabled architecture can benefit from compressed dtbs as well.
Move symbol and code to a comm place to be able to use it from RISC-V
in a later commit. In order not to break out of tree boards at runtime,
the old symbol name is maintained for ARM.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 33 insertions, 0 deletions

diff --git a/include/compressed-dtb.h b/include/compressed-dtb.h
new file mode 100644
index 0000000000..1ba98a7e2b
--- /dev/null
+++ b/include/compressed-dtb.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef COMPRESSED_DTB_H_
+#define COMPRESSED_DTB_H_
+
+#include <linux/types.h>
+#include <asm/unaligned.h>
+
+struct barebox_boarddata_compressed_dtb {
+#define BAREBOX_BOARDDATA_COMPRESSED_DTB_MAGIC 0x7b66bcbd
+	u32 magic;
+	u32 datalen;
+	u32 datalen_uncompressed;
+};
+
+static inline bool blob_is_compressed_fdt(const void *blob)
+{
+	const struct barebox_boarddata_compressed_dtb *dtb = blob;
+
+	return dtb->magic == BAREBOX_BOARDDATA_COMPRESSED_DTB_MAGIC;
+}
+
+static inline bool fdt_blob_can_be_decompressed(const void *blob)
+{
+	return IS_ENABLED(CONFIG_USE_COMPRESSED_DTB) && blob
+			&& blob_is_compressed_fdt(blob);
+}
+
+static inline bool blob_is_fdt(const void *blob)
+{
+	return get_unaligned_be32(blob) == FDT_MAGIC;
+}
+
+#endif