binman: Allow setting the ROM offset

On x86 the SPI ROM can be memory-mapped, at least most of it. Add a way
to tell binman the offset from a ROM address to a RAM address.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/binman.h b/include/binman.h
index b462dc8..baf49f7 100644
--- a/include/binman.h
+++ b/include/binman.h
@@ -21,6 +21,14 @@
 };
 
 /**
+ * binman_set_rom_offset() - Set the ROM memory-map offset
+ *
+ * @rom_offset: Offset from an image_pos to the memory-mapped address. This
+ *	tells binman that ROM image_pos x can be addressed at rom_offset + x
+ */
+void binman_set_rom_offset(int rom_offset);
+
+/**
  * binman_entry_find() - Find a binman symbol
  *
  * This searches the binman information in the device tree for a symbol of the
diff --git a/lib/binman.c b/lib/binman.c
index fd7de24..dc3a880 100644
--- a/lib/binman.c
+++ b/lib/binman.c
@@ -12,10 +12,21 @@
 #include <log.h>
 #include <malloc.h>
 
+/**
+ * struct binman_info - Information needed by the binman library
+ *
+ * @image: Node describing the image we are running from
+ * @rom_offset: Offset from an image_pos to the memory-mapped address, or
+ *	ROM_OFFSET_NONE if the ROM is not memory-mapped. Can be positive or
+ *	negative
+ */
 struct binman_info {
 	ofnode image;
+	int rom_offset;
 };
 
+#define ROM_OFFSET_NONE		(-1)
+
 static struct binman_info *binman;
 
 int binman_entry_find(const char *name, struct binman_entry *entry)
@@ -37,6 +48,11 @@
 	return 0;
 }
 
+void binman_set_rom_offset(int rom_offset)
+{
+	binman->rom_offset = rom_offset;
+}
+
 int binman_init(void)
 {
 	binman = malloc(sizeof(struct binman_info));
@@ -45,6 +61,7 @@
 	binman->image = ofnode_path("/binman");
 	if (!ofnode_valid(binman->image))
 		return log_msg_ret("binman node", -EINVAL);
+	binman->rom_offset = ROM_OFFSET_NONE;
 
 	return 0;
 }