[PATCH 4/4] fdt: Obtain the FDT from bloblist without parsing it

[Simon Glass]

We don't need or want to parse the bloblist to obtain the FDT. Use the
feature in the transfer list that was designed for this situation.

This avoids the complexity of trying to init the bloblist twice before
relocation.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 common/bloblist.c  | 32 +++++++++++++++++++++++++++++---
 include/bloblist.h | 11 +++++++++++
 lib/fdtdec.c       | 11 ++++-------
 3 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/common/bloblist.c b/common/bloblist.c
index 83d9de2749e..6bef1ab1895 100644
--- a/common/bloblist.c
+++ b/common/bloblist.c
@@ -596,11 +596,17 @@ int bloblist_maybe_init(void)
 	return 0;
 }
 
-int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig, ulong xlist)
+/**
+ * has_signature() - Check if the bloblist signature is in the registers
+ *
+ * @rzero: Register which should be zero
+ * @rsig: Register which should have the bloblist signature
+ * Return: true if signature found, false if not
+ */
+static bool has_signature(ulong rzero, ulong rsig)
 {
 	u64 version = BLOBLIST_REGCONV_VER;
 	ulong sigval;
-	int ret;
 
 	if ((IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_SPL_BUILD)) ||
 			(IS_ENABLED(CONFIG_SPL_64BIT) && IS_ENABLED(CONFIG_SPL_BUILD))) {
@@ -612,7 +618,17 @@ int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig, ulong xlist)
 	}
 
 	if (rzero || rsig != sigval)
-		return -EIO;
+		return false;
+
+	return true;
+}
+
+int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig, ulong xlist)
+{
+	int ret;
+
+	if (!has_signature(rzero, rsig))
+		return -ENOENT;
 
 	ret = bloblist_check(xlist, 0);
 	if (ret)
@@ -623,3 +639,13 @@ int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig, ulong xlist)
 
 	return 0;
 }
+
+void *bloblist_early_get_fdt(void)
+{
+	ulong addr, fdt;
+
+	if (xferlist_from_boot_arg(&addr, &fdt))
+		return NULL;
+
+	return map_sysmem(fdt, 0);
+}
diff --git a/include/bloblist.h b/include/bloblist.h
index 7ff70e9554c..8be871f2d98 100644
--- a/include/bloblist.h
+++ b/include/bloblist.h
@@ -515,4 +515,15 @@ int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig, ulong xlist);
  */
 int xferlist_from_boot_arg(ulong *addrp, ulong *fdtp);
 
+/**
+ * bloblist_early_get_fdt() - Get the FDT from a bloblist before it is set up
+ *
+ * The transfer list calling convention specifies that the FDT can be obtained
+ * without parsing the bloblist. Check for the presence of a bloblist and return
+ * the FDT indicated
+ *
+ * Return: Pointer to FDT or NULL if no bloblist is present
+ */
+void *bloblist_early_get_fdt(void);
+
 #endif /* __BLOBLIST_H */
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 833f8aca3ce..afa51f34867 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1692,17 +1692,14 @@ int fdtdec_setup(void)
 	int ret;
 
 	if (CONFIG_IS_ENABLED(OF_BLOBLIST)) {
-		ret = bloblist_maybe_init();
-		if (ret)
-			return ret;
-		gd->fdt_blob = bloblist_find(BLOBLISTT_CONTROL_FDT, 0);
-		if (!gd->fdt_blob) {
+		const void *blob;
+
+		blob = bloblist_early_get_fdt();
+		if (!blob) {
 			printf("Not FDT found in bloblist\n");
-			bloblist_show_list();
 			return -ENOENT;
 		}
 		gd->fdt_src = FDTSRC_BLOBLIST;
-		bloblist_show_list();
 		log_debug("Devicetree is in bloblist at %p\n", gd->fdt_blob);
 	} else {
 		if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
-- 
2.43.0