[PATCH 1/2] bloblist: Introduce BLOBLIST_PRIOR_STAGE options

[Tom Rini]

Introduce an option to control if we expect that a prior stage has
created a bloblist already and thus it is safe to scan the address. We
need to have this be configurable because we do not (and cannot) know if
the address at CONFIG_BLOBLIST_ADDR is in regular DRAM or some special
on-chip memory and so it may or may not be safe to read from this
address this early.

Signed-off-by: Tom Rini <trini at konsulko.com>
---
Cc: Simon Glass <sjg at chromium.org>
---
 common/Kconfig | 32 ++++++++++++++++++++++++++++++++
 lib/fdtdec.c   | 11 +++--------
 2 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/common/Kconfig b/common/Kconfig
index e8d89bf6eb9d..e8febad0f212 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -1077,6 +1077,14 @@ config BLOBLIST_SIZE
 	  is set up in the first part of U-Boot to run (TPL, SPL or U-Boot
 	  proper), and this sane bloblist is used for subsequent phases.
 
+config BLOBLIST_PRIOR_STAGE
+	bool "Bloblist was created in a stage prior to U-Boot"
+	default y
+	depends on BLOBLIST_FIXED
+	help
+	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created
+	  before U-Boot is started.
+
 config BLOBLIST_SIZE_RELOC
 	hex "Size of bloblist after relocation"
 	default BLOBLIST_SIZE if BLOBLIST_FIXED || BLOBLIST_ALLOC
@@ -1117,6 +1125,14 @@ config SPL_BLOBLIST_ALLOC
 
 endchoice
 
+config SPL_BLOBLIST_PRIOR_STAGE
+	bool "Bloblist was created in a stage prior to SPL"
+	default y
+	depends on SPL_BLOBLIST_FIXED
+	help
+	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created before
+	  U-Boot SPL is started.
+
 endif # SPL_BLOBLIST
 
 if TPL_BLOBLIST
@@ -1146,6 +1162,14 @@ config TPL_BLOBLIST_ALLOC
 
 endchoice
 
+config TPL_BLOBLIST_PRIOR_STAGE
+	bool "Bloblist was created in a stage prior to TPL"
+	default y
+	depends on TPL_BLOBLIST_FIXED
+	help
+	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created before
+	  U-Boot TPL is started.
+
 endif # TPL_BLOBLIST
 
 if VPL_BLOBLIST
@@ -1175,6 +1199,14 @@ config VPL_BLOBLIST_ALLOC
 
 endchoice
 
+config VPL_BLOBLIST_PRIOR_STAGE
+	bool "Bloblist was created in a stage prior to VPL"
+	default y
+	depends on VPL_BLOBLIST_FIXED
+	help
+	  Select this if the bloblist at CONFIG_BLOBLIST_ADDR was created before
+	  U-Boot VPL is started.
+
 endif # VPL_BLOBLIST
 
 endmenu
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index b06559880296..29bddab4150c 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1669,15 +1669,10 @@ int fdtdec_setup(void)
 	int ret = -ENOENT;
 
 	/*
-	 * If allowing a bloblist, check that first. There was discussion about
-	 * adding an OF_BLOBLIST Kconfig, but this was rejected.
-	 *
-	 * The necessary test is whether the previous phase passed a bloblist,
-	 * not whether this phase creates one.
+	 * Only scan for a bloblist and then if that bloblist contains a device
+	 * tree if we have been configured to expect one.
 	 */
-	if (CONFIG_IS_ENABLED(BLOBLIST) &&
-	    (xpl_prev_phase() != PHASE_TPL ||
-	     !IS_ENABLED(CONFIG_TPL_BLOBLIST))) {
+	if (CONFIG_IS_ENABLED(BLOBLIST_PRIOR_STAGE)) {
 		ret = bloblist_maybe_init();
 		if (!ret) {
 			gd->fdt_blob = bloblist_find(BLOBLISTT_CONTROL_FDT, 0);
-- 
2.43.0