[PATCH v2 15/18] fdt: Allow the devicetree to come from a bloblist

[Raymond Mao]

From: Simon Glass <sjg at chromium.org>

Standard passage provides for a bloblist to be passed from one firmware
phase to the next. That can be used to pass the devicetree along as well.
If CONFIG_OF_BOARD is defined, a board custom routine will provide a
bloblist or a specified memory address to retrieve the devicetree at
runtime.
A devicetree from a bloblist is prioritized than the one from specified
memory region.

Tests for this will be added as part of the Universal Payload work.

Signed-off-by: Simon Glass <sjg at chromium.org>
Co-developed-by: Raymond Mao <raymond.mao at linaro.org>
Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
---
Changes in v2
- New patch file created for v2.
  Amended from the original patch
  "[v2,30/32] fdt: Allow the devicetree to come from a bloblist".
  Remove CONFIG_OF_BLOBLIST and FDTSRC_BLOBLIST, a DTB from a previous
  loader is defined by CONFIG_OF_BOARD. The DTB can be located either in the
  bloblist or from a specified memory address.

 doc/develop/devicetree/control.rst |  8 +++--
 dts/Kconfig                        |  9 ++++--
 include/fdtdec.h                   |  3 +-
 lib/fdtdec.c                       | 52 +++++++++++++++++++++++-------
 4 files changed, 53 insertions(+), 19 deletions(-)

diff --git a/doc/develop/devicetree/control.rst b/doc/develop/devicetree/control.rst
index cbb65c9b17..a7f0f87841 100644
--- a/doc/develop/devicetree/control.rst
+++ b/doc/develop/devicetree/control.rst
@@ -104,9 +104,11 @@ in u-boot.bin so you can still just flash u-boot.bin onto your board. If you are
 using CONFIG_SPL_FRAMEWORK, then u-boot.img will be built to include the device
 tree binary.
 
-If CONFIG_OF_BOARD is defined, a board-specific routine will provide the
-devicetree at runtime, for example if an earlier bootloader stage creates
-it and passes it to U-Boot.
+If CONFIG_OF_BOARD is defined, a board-specific routine will provide a bloblist
+or a specified memory region to retrieve the devicetree at runtime, for example
+if an earlier bootloader stage creates it and passes it to U-Boot.
+A devicetree from a bloblist is prioritized than the one from a specified memory
+region.
 
 If CONFIG_SANDBOX is defined, then it will be read from a file on
 startup. Use the -d flag to U-Boot to specify the file to read, -D for the
diff --git a/dts/Kconfig b/dts/Kconfig
index 00c0aeff89..4faf4ba633 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -110,8 +110,13 @@ config OF_BOARD
 	default y if SANDBOX || OF_HAS_PRIOR_STAGE
 	help
 	  If this option is enabled, the device tree is provided at runtime by
-	  a custom function called board_fdt_blob_setup(). The board must
-	  implement this function if it wishes to provide special behaviour.
+	  bloblist via a custom function called board_bloblist_from_boot_arg()
+	  or a memory region from a custom function called
+	  board_fdt_blob_setup(). The board must implement either these
+	  functions if it wishes to provide special behaviour.
+
+	  A devicetree from a bloblist is prioritized then the one from a
+	  specified memory region if the board provides both methods.
 
 	  With this option, the device tree build by U-Boot may be overridden or
 	  ignored. See OF_HAS_PRIOR_STAGE.
diff --git a/include/fdtdec.h b/include/fdtdec.h
index bd1149f46d..0824fe1359 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -72,14 +72,13 @@ struct bd_info;
  *	U-Boot is packaged as an ELF file, e.g. for debugging purposes
  * @FDTSRC_ENV: Provided by the fdtcontroladdr environment variable. This should
  *	be used for debugging/development only
- * @FDTSRC_NONE: No devicetree at all
  */
 enum fdt_source_t {
 	FDTSRC_SEPARATE,
 	FDTSRC_FIT,
 	FDTSRC_BOARD,
 	FDTSRC_EMBED,
-	FDTSRC_ENV,
+	FDTSRC_ENV
 };
 
 /*
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 7a69167648..025baca4a4 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -7,7 +7,11 @@
  */
 
 #ifndef USE_HOSTCC
+
+#define LOG_CATEGORY	LOGC_DT
+
 #include <common.h>
+#include <bloblist.h>
 #include <boot_fit.h>
 #include <display_options.h>
 #include <dm.h>
@@ -86,7 +90,7 @@ static const char *const fdt_src_name[] = {
 	[FDTSRC_FIT] = "fit",
 	[FDTSRC_BOARD] = "board",
 	[FDTSRC_EMBED] = "embed",
-	[FDTSRC_ENV] = "env",
+	[FDTSRC_ENV] = "env"
 };
 
 const char *fdtdec_get_srcname(void)
@@ -1665,21 +1669,45 @@ int fdtdec_setup(void)
 {
 	int ret;
 
-	/* The devicetree is typically appended to U-Boot */
-	if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
-		gd->fdt_blob = fdt_find_separate();
-		gd->fdt_src = FDTSRC_SEPARATE;
-	} else { /* embed dtb in ELF file for testing / development */
-		gd->fdt_blob = dtb_dt_embedded();
-		gd->fdt_src = FDTSRC_EMBED;
-	}
-
-	/* Allow the board to override the fdt address. */
+	/*
+	 * The devicetree is typically appended to U-Boot.
+	 * Option 1: From bloblist.
+	 * Option 2: From a specified memory address.
+	 */
 	if (IS_ENABLED(CONFIG_OF_BOARD)) {
-		gd->fdt_blob = board_fdt_blob_setup(&ret);
+		/*
+		 * DTB is from board.
+		 * Either from bloblist or a platform specified memory.
+		 */
+		ret = bloblist_maybe_init();
 		if (ret)
 			return ret;
+
+		/* Check if a DTB exists in bloblist first */
+		if (IS_ENABLED(CONFIG_BLOBLIST)) {
+			gd->fdt_blob = bloblist_find(BLOBLISTT_CONTROL_FDT, 0);
+			if (gd->fdt_blob) {
+				log_info("Fdt from bloblist at 0x%lx\n",
+					 (unsigned long)gd->fdt_blob);
+			}
+		}
+		if (!gd->fdt_blob) {
+			/* Apply DTB from a platform specified memory */
+			gd->fdt_blob = board_fdt_blob_setup(&ret);
+			if (ret)
+				return ret;
+			log_info("Fdt from memory at 0x%lx\n",
+				 (unsigned long)gd->fdt_blob);
+		}
 		gd->fdt_src = FDTSRC_BOARD;
+	} else {
+		if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
+			gd->fdt_blob = fdt_find_separate();
+			gd->fdt_src = FDTSRC_SEPARATE;
+		} else { /* embed dtb in ELF file for testing / development */
+			gd->fdt_blob = dtb_dt_embedded();
+			gd->fdt_src = FDTSRC_EMBED;
+		}
 	}
 
 	/* Allow the early environment to override the fdt address */
-- 
2.25.1