bloblist: Load the bloblist from the previous loader

During bloblist initialization, when CONFIG_OF_BOARD is defined,
invoke the platform custom function to load the bloblist via boot
arguments from the previous loader.
If the bloblist exists, copy it into the fixed bloblist memory region.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>

common/bloblist.c

@@ -477,30 +477,26 @@ int bloblist_init(void)
 	bool fixed = IS_ENABLED(CONFIG_BLOBLIST_FIXED);
 	int ret = -ENOENT;
 	ulong addr, size;
-	bool expected;
-
-	/**
-	 * We don't expect to find an existing bloblist in the first phase of
-	 * U-Boot that runs. Also we have no way to receive the address of an
-	 * allocated bloblist from a previous stage, so it must be at a fixed
-	 * address.
-	 */
-	expected = fixed && !u_boot_first_phase();
+	bool expected = fixed;
+
 	if (spl_prev_phase() == PHASE_TPL && !IS_ENABLED(CONFIG_TPL_BLOBLIST))
 		expected = false;
 	if (fixed)
 		addr = IF_ENABLED_INT(CONFIG_BLOBLIST_FIXED,
 				      CONFIG_BLOBLIST_ADDR);
 	size = CONFIG_BLOBLIST_SIZE;
 	if (expected) {
-		ret = bloblist_check(addr, size);
-		if (ret) {
-			log_warning("Expected bloblist at %lx not found (err=%d)\n",
+		if (IS_ENABLED(CONFIG_OF_BOARD))
+			/* Get the bloblist from previous loader */
+			ret = board_bloblist_from_boot_arg(addr, size);
+		else
+			ret = bloblist_check(addr, size);
+
+		if (ret)
+			log_warning("Bloblist at %lx not found, err=%d\n",
 				    addr, ret);
-		} else {
-			/* Get the real size, if it is not what we expected */
+		else
 			size = gd->bloblist->total_size;
-		}
 	}
 	if (ret) {
 		if (CONFIG_IS_ENABLED(BLOBLIST_ALLOC)) {
@@ -510,7 +506,8 @@ int bloblist_init(void)
 				return log_msg_ret("alloc", -ENOMEM);
 			addr = map_to_sysmem(ptr);
 		} else if (!fixed) {
-			return log_msg_ret("!fixed", ret);
+			return log_msg_ret("BLOBLIST_FIXED is not enabled",
+					   ret);
 		}
 		log_debug("Creating new bloblist size %lx at %lx\n", size,
 			  addr);

include/bloblist.h

@@ -438,6 +438,20 @@ void bloblist_reloc(void *to, uint to_size, void *from, uint from_size);
  */
 int bloblist_init(void);
 
+#if CONFIG_IS_ENABLED(ARCH_QEMU)
+int board_bloblist_from_boot_arg(unsigned long addr, unsigned long size);
+#else
+/*
+ * A board need to implement this custom function if it needs to retrieve
+ * bloblist from a previous loader
+ */
+static inline int board_bloblist_from_boot_arg(unsigned long __always_unused addr,
+					       unsigned long __always_unused size)
+{
+	return -1;
+}
+#endif
+
 #if CONFIG_IS_ENABLED(BLOBLIST)
 /**
  * bloblist_maybe_init() - Init the bloblist system if not already done