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Add barebox overlay support
This commit is contained in:
Pascal Vizeli
parent
50cc88832d
commit
0638bac388
@ -0,0 +1,429 @@
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From 059762285f200a6e2527a4447d35f34d66b07bc2 Mon Sep 17 00:00:00 2001
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From: Pascal Vizeli <pvizeli@syshack.ch>
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Date: Sun, 27 May 2018 09:33:20 +0000
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Subject: [PATCH 1/2] drivers: of: implement overlay support
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Signed-off-by: Pascal Vizeli <pvizeli@syshack.ch>
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---
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Documentation/user/devicetree.rst | 101 +++++++++++++++++++++++++++++-
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arch/sandbox/dts/Makefile | 5 +-
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arch/sandbox/dts/sandbox.dts | 6 ++
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commands/oftree.c | 65 +++++++++++++++++--
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drivers/of/Kconfig | 6 ++
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drivers/of/Makefile | 1 +
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include/of.h | 71 +++++++++++++++++++++
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scripts/Makefile.lib | 5 +-
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8 files changed, 251 insertions(+), 9 deletions(-)
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diff --git a/Documentation/user/devicetree.rst b/Documentation/user/devicetree.rst
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index 17934d86e..b2220997d 100644
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--- a/Documentation/user/devicetree.rst
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+++ b/Documentation/user/devicetree.rst
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@@ -21,7 +21,7 @@ The internal devicetree
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-----------------------
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The devicetree consulted by barebox plays a special role. It is referred to
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-as the "internal devicetree." The barebox devicetree commands work on this
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+as the "internal devicetree". The barebox devicetree commands work on this
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devicetree. The devicetree source (DTS) files are kept in sync with the kernel DTS
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files. As the FDT files are meant to be backward compatible, it should always be possible
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to start a kernel with the barebox internal devicetree. However, since the barebox
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@@ -83,3 +83,102 @@ you can exchange the internal devicetree during runtime using the
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oftree -f
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oftree -l /new/dtb
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+
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+Devicetree overlays
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+-------------------
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+
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+Since version 3.19, the Linux kernel supports applying "devicetree overlays" to
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+its loaded device tree. This can be used to inform the kernel about additional
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+non-discoverable devices after the system has booted, which is useful for modular
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+boards and FPGAs. The details of the overlay format are specified in the Linux
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+`kernel documentation <https://www.kernel.org/doc/Documentation/devicetree/overlay-notes.txt>`_
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+and an updated DTC is required to compile the overlays.
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+
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+The use cases for overlays in barebox are a bit different:
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+
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+* some of the modular devices are needed to boot Linux to userspace, but barebox
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+ can detect which module variant is connected
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+* one of several parallel or LVDS displays (which use timing data from devicetree)
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+ can be connected to the SoC and should be used for boot messages
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+* a generic Linux (distribution) kernel should be booted on a modular
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+ system and support additional hardware on modules
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+
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+barebox supports applying overlays in the internal devicetree was well using the
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+:ref:`command_oftree` command with option ``-o``:
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+
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+.. code-block:: sh
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+
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+ $ ./barebox -d arch/sandbox/dts/sandbox.dtb -i arch/sandbox/dts/sandbox-overlay.dtbo
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+ add fd0 backed by file arch/sandbox/dts/sandbox-overlay.dtbo
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+
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+ barebox 2015.02.0 #26 Wed Mar 4 09:41:19 CET 2015
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+ ...
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+ barebox@barebox sandbox:/ of_dump
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+ ...
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+ dummy@0 {
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+ status = "disabled";
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+ linux,phandle = <0x1>;
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+ phandle = <0x1>;
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+ };
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+ dummy@1 {
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+ status = "disabled";
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+ linux,phandle = <0x2>;
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+ phandle = <0x2>;
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+ };
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+ __symbols__ {
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+ dummy0 = "/dummy@0";
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+ dummy1 = "/dummy@1";
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+ };
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+ ...
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+ barebox@barebox sandbox:/ of_dump -f /dev/fd0
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+ {
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+ fragment@0 {
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+ target = <0xdeadbeef>;
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+ __overlay__ {
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+ status = "okay";
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+ child {
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+ compatible = "barebox,dummy";
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+ };
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+ };
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+ };
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+ fragment@1 {
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+ target = <0xdeadbeef>;
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+ __overlay__ {
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+ status = "okay";
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+ child {
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+ compatible = "barebox,dummy";
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+ };
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+ };
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+ };
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+ __fixups__ {
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+ dummy0 = "/fragment@0:target:0";
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+ dummy1 = "/fragment@1:target:0";
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+ };
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+ };
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+ barebox@barebox sandbox:/ oftree -o /dev/fd0
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+ barebox@barebox sandbox:/ of_dump
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+ ...
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+ dummy@0 {
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+ linux,phandle = <0x1>;
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+ phandle = <0x1>;
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+ status = "okay";
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+ child {
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+ compatible = "barebox,dummy";
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+ };
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+ };
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+ dummy@1 {
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+ linux,phandle = <0x2>;
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+ phandle = <0x2>;
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+ status = "okay";
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+ child {
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+ compatible = "barebox,dummy";
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+ };
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+ };
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+ __symbols__ {
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+ dummy0 = "/dummy@0";
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+ dummy1 = "/dummy@1";
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+ };
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+ ...
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+
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+If you need to use a different base devicetree instead of the one compiled into
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+barebox, it needs to be replaced as described in the previous section.
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diff --git a/arch/sandbox/dts/Makefile b/arch/sandbox/dts/Makefile
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index 6f6838857..ede219e6f 100644
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--- a/arch/sandbox/dts/Makefile
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+++ b/arch/sandbox/dts/Makefile
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@@ -1,6 +1,7 @@
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ifeq ($(CONFIG_OFTREE),y)
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dtb-y += \
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- sandbox.dtb
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+ sandbox.dtb \
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+ sandbox-overlay.dtbo
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endif
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# just to build a built-in.o. Otherwise compilation fails when no devicetree is
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@@ -8,4 +9,4 @@ endif
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obj- += dummy.o
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always := $(dtb-y)
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-clean-files := *.dtb *.dtb.S .*.dtc .*.pre .*.dts
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+clean-files := *.dtb *.dtb.S .*.dtc .*.pre .*.dts *.dtbo
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diff --git a/arch/sandbox/dts/sandbox.dts b/arch/sandbox/dts/sandbox.dts
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index 2595aa13f..1b99a4960 100644
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--- a/arch/sandbox/dts/sandbox.dts
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+++ b/arch/sandbox/dts/sandbox.dts
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@@ -3,5 +3,11 @@
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#include "skeleton.dtsi"
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/ {
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+ dummy0: dummy@0 {
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+ status = "disabled";
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+ };
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+ dummy1: dummy@1 {
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+ status = "disabled";
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+ };
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};
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diff --git a/commands/oftree.c b/commands/oftree.c
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index 8a47c0be5..e0624ad34 100644
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--- a/commands/oftree.c
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+++ b/commands/oftree.c
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@@ -2,6 +2,7 @@
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* oftree.c - device tree command support
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*
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* Copyright (c) 2011 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
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+ * Copyright (C) 2015 Pengutronix, Jan Luebbe <jlu@pengutronix.de>
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*
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* based on U-Boot code by:
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*
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@@ -48,11 +49,14 @@ static int do_oftree(int argc, char *argv[])
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int probe = 0;
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char *load = NULL;
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char *save = NULL;
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+ char *overlay = NULL;
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int free_of = 0;
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int ret;
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struct device_node *root;
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+ int ovinfo_cnt;
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+ struct of_overlay_info *ovinfo;
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- while ((opt = getopt(argc, argv, "pfl:s:")) > 0) {
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+ while ((opt = getopt(argc, argv, "pfl:o:s:")) > 0) {
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switch (opt) {
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case 'l':
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load = optarg;
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@@ -68,6 +72,9 @@ static int do_oftree(int argc, char *argv[])
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case 'f':
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free_of = 1;
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break;
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+ case 'o':
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+ overlay = optarg;
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+ break;
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case 's':
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save = optarg;
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break;
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@@ -84,7 +91,7 @@ static int do_oftree(int argc, char *argv[])
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return 0;
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}
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- if (!probe && !load && !save)
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+ if (!probe && !load && !save && !overlay)
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return COMMAND_ERROR_USAGE;
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if (save) {
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@@ -123,6 +130,53 @@ static int do_oftree(int argc, char *argv[])
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}
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}
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+ if (IS_ENABLED(CONFIG_OFTREE_OVERLAY) && overlay) {
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+ struct device_node *ov;
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+
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+ root = of_get_root_node();
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+ if (!root) {
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+ printf("no oftree loaded\n");
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+ goto out;
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+ }
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+
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+ fdt = read_file(overlay, &size);
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+ if (!fdt) {
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+ printf("unable to read %s\n", overlay);
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+ return 1;
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+ }
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+
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+ ov = of_unflatten_dtb(fdt);
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+ free(fdt);
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+
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+ if (IS_ERR(ov)) {
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+ printf("parse oftree: %s\n", strerror(-ret));
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+ return PTR_ERR(ov);
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+ }
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+
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+ ret = of_resolve(ov);
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+ if (ret) {
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+ printf("resolve oftree overlay: %s\n", strerror(-ret));
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+ of_delete_node(ov);
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+ goto out;
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+ }
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+
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+ ret = of_build_overlay_info(ov, &ovinfo_cnt, &ovinfo);
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+ if (ret) {
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+ printf("prepare oftree overlay: %s\n", strerror(-ret));
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+ of_delete_node(ov);
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+ goto out;
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+ }
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+
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+ ret = of_overlay(ovinfo_cnt, ovinfo);
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+ if (ret) {
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+ printf("apply oftree overlay: %s\n", strerror(-ret));
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+ of_delete_node(ov);
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+ goto out;
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+ }
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+
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+ of_delete_node(ov);
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+ }
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+
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if (probe) {
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ret = of_probe();
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if (ret)
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@@ -137,8 +191,9 @@ out:
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BAREBOX_CMD_HELP_START(oftree)
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BAREBOX_CMD_HELP_TEXT("Options:")
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-BAREBOX_CMD_HELP_OPT ("-l <DTB>", "Load <DTB> to internal devicetree\n")
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-BAREBOX_CMD_HELP_OPT ("-s <DTB>", "save internal devicetree to <DTB>\n")
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+BAREBOX_CMD_HELP_OPT ("-l <DTB>", "load <DTB> to internal devicetree")
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+BAREBOX_CMD_HELP_OPT ("-s <DTB>", "save internal devicetree to <DTB>")
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+BAREBOX_CMD_HELP_OPT ("-o <DTBO>", "apply overlay <DTBO> to internal devicetree")
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BAREBOX_CMD_HELP_OPT ("-p", "probe devices from stored device tree")
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BAREBOX_CMD_HELP_OPT ("-f", "free stored device tree")
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BAREBOX_CMD_HELP_END
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@@ -146,7 +201,7 @@ BAREBOX_CMD_HELP_END
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BAREBOX_CMD_START(oftree)
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.cmd = do_oftree,
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BAREBOX_CMD_DESC("handle device trees")
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- BAREBOX_CMD_OPTS("[-lspf]")
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+ BAREBOX_CMD_OPTS("[-lsopf]")
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BAREBOX_CMD_GROUP(CMD_GRP_MISC)
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BAREBOX_CMD_HELP(cmd_oftree_help)
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BAREBOX_CMD_END
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diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
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index a1fac0e61..d90bd9c6b 100644
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--- a/drivers/of/Kconfig
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+++ b/drivers/of/Kconfig
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@@ -15,6 +15,12 @@ config OFDEVICE
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select DTC
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bool "Enable probing of devices from the devicetree"
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+config OFTREE_OVERLAY
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+ bool "Enable support for devicetree overlays"
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+ depends on OFTREE
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+ help
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+ Allows you to modify the live tree using overlays.
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+
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config OF_ADDRESS_PCI
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bool
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diff --git a/drivers/of/Makefile b/drivers/of/Makefile
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index ec4387006..323543461 100644
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--- a/drivers/of/Makefile
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+++ b/drivers/of/Makefile
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@@ -6,3 +6,4 @@ obj-y += partition.o
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obj-y += of_net.o
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obj-$(CONFIG_MTD) += of_mtd.o
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obj-$(CONFIG_OF_BAREBOX_DRIVERS) += barebox.o
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+obj-$(CONFIG_OFTREE_OVERLAY) += resolver.o overlay.o
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diff --git a/include/of.h b/include/of.h
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index fec51bb94..91476ae47 100644
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--- a/include/of.h
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+++ b/include/of.h
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@@ -730,6 +730,8 @@ static inline struct device_node *of_find_matching_node(
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#define for_each_available_child_of_node(parent, child) \
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for (child = of_get_next_available_child(parent, NULL); child != NULL; \
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child = of_get_next_available_child(parent, child))
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+#define for_each_property_of_node(dn, pp) \
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+ list_for_each_entry(pp, &dn->properties, list)
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/**
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* of_property_read_bool - Findfrom a property
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@@ -850,4 +852,73 @@ static inline struct device_node *of_find_root_node(struct device_node *node)
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return node;
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}
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+
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+/* illegal phandle value (set when unresolved) */
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+#define OF_PHANDLE_ILLEGAL 0xdeadbeef
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+
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+#ifdef CONFIG_OFTREE_OVERLAY
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+
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+extern int of_resolve(struct device_node *resolve);
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+
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+#else
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+
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+static inline int of_resolve(struct device_node *resolve)
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+{
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+ return -ENOSYS;
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+}
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+
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+#endif
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+
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+/**
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+ * Overlay support
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+ */
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+
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+/**
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+ * struct of_overlay_info - Holds a single overlay info
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+ * @target: target of the overlay operation
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+ * @overlay: pointer to the overlay contents node
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+ *
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+ * Holds a single overlay state.
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+ */
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+struct of_overlay_info {
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+ struct device_node *target;
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+ struct device_node *overlay;
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+};
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+
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+#ifdef CONFIG_OFTREE_OVERLAY
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+
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+extern int of_overlay(int count, struct of_overlay_info *ovinfo_tab);
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+
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+extern int of_fill_overlay_info(struct device_node *info_node,
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+ struct of_overlay_info *ovinfo);
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+extern int of_build_overlay_info(struct device_node *tree,
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+ int *cntp, struct of_overlay_info **ovinfop);
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+extern int of_free_overlay_info(int cnt, struct of_overlay_info *ovinfo);
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+
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+#else
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+
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+static inline int of_overlay(int count, struct of_overlay_info *ovinfo_tab)
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+{
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+ return -ENOSYS;
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+}
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+
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+static inline int of_fill_overlay_info(struct device_node *info_node,
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+ struct of_overlay_info *ovinfo)
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+{
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+ return -ENOSYS;
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+}
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+
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+static inline int of_build_overlay_info(struct device_node *tree,
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+ int *cntp, struct of_overlay_info **ovinfop)
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+{
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+ return -ENOSYS;
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+}
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+
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+static inline int of_free_overlay_info(int cnt, struct of_overlay_info *ovinfo)
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+{
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+ return -ENOSYS;
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+}
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+
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+#endif
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+
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#endif /* __OF_H */
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diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
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index 272b5981e..e7cea55c4 100644
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--- a/scripts/Makefile.lib
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+++ b/scripts/Makefile.lib
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@@ -261,7 +261,7 @@ $(obj)/%.dtb.S: $(obj)/%.dtb $(srctree)/scripts/gen-dtb-s FORCE
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quiet_cmd_dtc = DTC $@
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cmd_dtc = $(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
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- $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 \
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+ $(objtree)/scripts/dtc/dtc -@ -O dtb -o $@ -b 0 \
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-i $(srctree)/arch/$(SRCARCH)/dts $(DTC_FLAGS) \
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-i $(srctree)/dts/src/$(SRCARCH) \
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-d $(depfile).dtc $(dtc-tmp) ; \
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@@ -270,6 +270,9 @@ cmd_dtc = $(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
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$(obj)/%.dtb: $(src)/%.dts FORCE
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$(call if_changed_dep,dtc)
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+$(obj)/%.dtbo: $(src)/%.dtso FORCE
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+ $(call if_changed_dep,dtc)
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+
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dtc-tmp = $(subst $(comma),_,$(dot-target).dts)
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obj-y += $(patsubst %,%.bbenv$(DEFAULT_COMPRESSION_SUFFIX).o,$(bbenv-y))
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--
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2.17.0
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File diff suppressed because it is too large
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