[PATCH 0/2] overlays: auto allocate phandles for nodes in base fdt

[PATCH 0/2] overlays: auto allocate phandles for nodes in base fdt

[kevans-HZy0K5TPuP5AfugRpC6u6w]

Nodes in the base fdt that do not have phandles cannot currently be referenced
in overlays; we can target them for an overlay, but we cannot use them as a
reference in another property if needed. This is quite limiting for some
use-cases where you're needing cross-references that don't currently exist in
the base.

Kyle Evans (2):
  fdt_overlay: Allocate phandles as needed for nodes referenced in base
    fdt
  fdt_overlay: Basic regression tests for automatically allocated
    phandles

 libfdt/fdt_overlay.c                               | 57 ++++++++++++++++++----
 tests/overlay_base_manual_symbols_auto_phandle.dts | 24 +++++++++
 tests/run_tests.sh                                 |  6 +++
 3 files changed, 78 insertions(+), 9 deletions(-)
 create mode 100644 tests/overlay_base_manual_symbols_auto_phandle.dts

-- 
2.15.1

[PATCH 1/2] overlays: auto allocate phandles for nodes in base fdt

[kevans-HZy0K5TPuP5AfugRpC6u6w]

Currently, references cannot be made to nodes in the base that do not already
have phandles, limiting us to nodes that have been referenced in the base fdt.
Lift that restriction by allocating them on an as-needed basis.

Signed-off-by: Kyle Evans <kevans-HZy0K5TPuP5AfugRpC6u6w@public.gmane.org>
---
 libfdt/fdt_overlay.c | 57 +++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 48 insertions(+), 9 deletions(-)

diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c
index bd81241..dcc2672 100644
--- a/libfdt/fdt_overlay.c
+++ b/libfdt/fdt_overlay.c
@@ -335,6 +335,40 @@ static int overlay_update_local_references(void *fdto, uint32_t delta)
 						    delta);
 }
 
+/**
+ * overlay_assign_phandle - Assign a phandle to a symbol in the base fdt
+ * @fdt: Base Device Tree blob
+ * @fdto: Device tree overlay blob
+ * @symbol_off: Node offset of the symbol to be assigned a phandle
+ *
+ * overlay_assign_phandle() assigns the next phandle available to the requested
+ * node in the base device tree.
+ *
+ * This is part of the device tree overlay application process, when
+ * you want to reference a symbol in the base device tree that doesn't yet have
+ * a phandle.
+ *
+ * returns:
+ *      phandle assigned on success
+ *      0 on failure
+ */
+static int overlay_assign_phandle(void *fdt, void *fdto, int symbol_off)
+{
+	int phandle, ret;
+	fdt32_t phandle_val;
+
+	/* Overlay phandles have already been adjusted */
+	phandle = fdt_get_max_phandle(fdto);
+	if (phandle < 0)
+		return 0;
+	phandle++;
+	phandle_val = cpu_to_fdt32(phandle);
+	ret = fdt_setprop(fdt, symbol_off, "phandle", &phandle_val, sizeof(phandle_val));
+	if (!ret)
+		return phandle;
+	return 0;
+}
+
 /**
  * overlay_fixup_one_phandle - Set an overlay phandle to the base one
  * @fdt: Base Device Tree blob
@@ -359,7 +393,7 @@ static int overlay_update_local_references(void *fdto, uint32_t delta)
  *      Negative error code on failure
  */
 static int overlay_fixup_one_phandle(void *fdt, void *fdto,
-				     int symbols_off,
+				     int *symbols_off,
 				     const char *path, uint32_t path_len,
 				     const char *name, uint32_t name_len,
 				     int poffset, const char *label)
@@ -370,10 +404,10 @@ static int overlay_fixup_one_phandle(void *fdt, void *fdto,
 	int symbol_off, fixup_off;
 	int prop_len;
 
-	if (symbols_off < 0)
-		return symbols_off;
+	if (*symbols_off < 0)
+		return *symbols_off;
 
-	symbol_path = fdt_getprop(fdt, symbols_off, label,
+	symbol_path = fdt_getprop(fdt, *symbols_off, label,
 				  &prop_len);
 	if (!symbol_path)
 		return prop_len;
@@ -383,8 +417,14 @@ static int overlay_fixup_one_phandle(void *fdt, void *fdto,
 		return symbol_off;
 
 	phandle = fdt_get_phandle(fdt, symbol_off);
-	if (!phandle)
-		return -FDT_ERR_NOTFOUND;
+	if (!phandle) {
+		phandle = overlay_assign_phandle(fdt, fdto, symbol_off);
+		if (phandle == 0)
+			return -FDT_ERR_NOTFOUND;
+
+		/* Re-lookup symbols offset, it's been invalidated */
+		*symbols_off = fdt_path_offset(fdt, "/__symbols__");
+	}
 
 	fixup_off = fdt_path_offset_namelen(fdto, path, path_len);
 	if (fixup_off == -FDT_ERR_NOTFOUND)
@@ -418,7 +458,7 @@ static int overlay_fixup_one_phandle(void *fdt, void *fdto,
  *      0 on success
  *      Negative error code on failure
  */
-static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,
+static int overlay_fixup_phandle(void *fdt, void *fdto, int *symbols_off,
 				 int property)
 {
 	const char *value;
@@ -519,8 +559,7 @@ static int overlay_fixup_phandles(void *fdt, void *fdto)
 
 	fdt_for_each_property_offset(property, fdto, fixups_off) {
 		int ret;
-
-		ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property);
+		ret = overlay_fixup_phandle(fdt, fdto, &symbols_off, property);
 		if (ret)
 			return ret;
 	}
-- 
2.15.1

[PATCH 2/2] overlays: auto allocate phandles for nodes in base fdt

[kevans-HZy0K5TPuP5AfugRpC6u6w]

The base dts is simply a copy of overlay_base_manual_symbols.dts with the forced
phandle removed, thus copyright notices remain intact.

Signed-off-by: Kyle Evans <kevans-HZy0K5TPuP5AfugRpC6u6w@public.gmane.org>
---
 tests/overlay_base_manual_symbols_auto_phandle.dts | 24 ++++++++++++++++++++++
 tests/run_tests.sh                                 |  6 ++++++
 2 files changed, 30 insertions(+)
 create mode 100644 tests/overlay_base_manual_symbols_auto_phandle.dts

diff --git a/tests/overlay_base_manual_symbols_auto_phandle.dts b/tests/overlay_base_manual_symbols_auto_phandle.dts
new file mode 100644
index 0000000..6acdcf8
--- /dev/null
+++ b/tests/overlay_base_manual_symbols_auto_phandle.dts
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2016 NextThing Co
+ * Copyright (c) 2016 Free Electrons
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/dts-v1/;
+
+/ {
+	test: test-node {
+		test-int-property = <42>;
+		test-str-property = "foo";
+
+		subtest: sub-test-node {
+			sub-test-property;
+		};
+	};
+	__symbols__ {
+		test = &test;
+	};
+};
+
+
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index d36dffb..6ed6d02 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -198,12 +198,18 @@ libfdt_overlay_tests () {
     run_test check_path overlay_base_manual_symbols.test.dtb not-exists "/__fixups__"
     run_test check_path overlay_base_manual_symbols.test.dtb not-exists "/__local_fixups__"
 
+    run_dtc_test -I dts -O dtb -o overlay_base_manual_symbols_auto_phandle.test.dtb overlay_base_manual_symbols_auto_phandle.dts
+    run_test check_path overlay_base_manual_symbols_auto_phandle.test.dtb exists "/__symbols__"
+    run_test check_path overlay_base_manual_symbols_auto_phandle.test.dtb not-exists "/__fixups__"
+    run_test check_path overlay_base_manual_symbols_auto_phandle.test.dtb not-exists "/__local_fixups__"
+
     run_dtc_test -I dts -O dtb -o overlay_overlay_manual_fixups.test.dtb overlay_overlay_manual_fixups.dts
     run_test check_path overlay_overlay_manual_fixups.test.dtb not-exists "/__symbols__"
     run_test check_path overlay_overlay_manual_fixups.test.dtb exists "/__fixups__"
     run_test check_path overlay_overlay_manual_fixups.test.dtb exists "/__local_fixups__"
 
     run_test overlay overlay_base_manual_symbols.test.dtb overlay_overlay_manual_fixups.test.dtb
+    run_test overlay overlay_base_manual_symbols_auto_phandle.test.dtb overlay_overlay_manual_fixups.test.dtb
 
     # test simplified plugin syntax
     run_dtc_test -@ -I dts -O dtb -o overlay_overlay_simple.dtb overlay_overlay_simple.dts
-- 
2.15.1