[RFC PATCH v2 13/74] Add support for /addon/ keyword

[Herve Codina <herve.codina@bootlin.com>]

The dts /addon/ keyword allows to mark a dts as an addon dts.

This is similar to /plugin/ used for overlay dts but specific to addon
dts.

It is also worth noting that a dts tagged with /addon/ will lead to a
dtb with the dt_flags set to FDT_FLAG_ADDON (0x1).

This allows to identify without any ambiguity an addon dts and an addon
dtb.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
---
 checks.c     | 36 +++++++++++++++++++++++-------------
 dtc-lexer.l  |  5 +++++
 dtc-parser.y |  5 +++++
 dtc.h        |  1 +
 fdtdump.c    |  4 ++++
 flattree.c   | 15 ++++++++++++---
 libfdt/fdt.h |  1 +
 treesource.c |  6 ++++++
 8 files changed, 57 insertions(+), 16 deletions(-)

diff --git a/checks.c b/checks.c
index a6037ed0..cb3b4b16 100644
--- a/checks.c
+++ b/checks.c
@@ -624,7 +624,7 @@ static void fixup_phandle_references(struct check *c, struct dt_info *dti,
 
 			refnode = get_node_by_ref(dt, m->ref);
 			if (! refnode) {
-				if (!(dti->dtsflags & DTSF_PLUGIN))
+				if (!(dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON)))
 					FAIL(c, dti, node, "Reference to non-existent node or "
 							"label \"%s\"\n", m->ref);
 				else /* mark the entry as unresolved */
@@ -726,8 +726,8 @@ static void check_alias_paths(struct check *c, struct dt_info *dti,
 			continue;
 		}
 
-		/* This check does not work for overlays with external paths */
-		if (!(dti->dtsflags & DTSF_PLUGIN) &&
+		/* This check does not work for overlays nor addons with external paths */
+		if (!(dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON)) &&
 		    (!prop->val.val || !get_node_by_path(dti->dt, prop->val.val))) {
 			FAIL_PROP(c, dti, node, prop, "aliases property is not a valid node (%s)",
 				  prop->val.val);
@@ -1425,8 +1425,8 @@ static void check_property_phandle_args(struct check *c,
 		 * entries when each index position has a specific definition.
 		 */
 		if (!phandle_is_valid(phandle)) {
-			/* Give up if this is an overlay with external references */
-			if (dti->dtsflags & DTSF_PLUGIN)
+			/* Give up if this is an overlay or addon with external references */
+			if (dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON))
 				break;
 
 			cellsize = 0;
@@ -1659,8 +1659,8 @@ static void check_interrupt_map(struct check *c,
 
 		phandle = propval_cell_n(irq_map_prop, cell);
 		if (!phandle_is_valid(phandle)) {
-			/* Give up if this is an overlay with external references */
-			if (!(dti->dtsflags & DTSF_PLUGIN))
+			/* Give up if this is an overlay or an addon with external references */
+			if (!(dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON)))
 				FAIL_PROP(c, dti, node, irq_map_prop,
 					  "Cell %zu is not a phandle(%d)",
 					  cell, phandle);
@@ -1728,9 +1728,9 @@ static void check_interrupts_property(struct check *c,
 		if (prop) {
 			phandle = propval_cell(prop);
 			if (!phandle_is_valid(phandle)) {
-				/* Give up if this is an overlay with
+				/* Give up if this is an overlay with or an addon
 				 * external references */
-				if (dti->dtsflags & DTSF_PLUGIN)
+				if (dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON))
 					return;
 				FAIL_PROP(c, dti, parent, prop, "Invalid phandle");
 				continue;
@@ -1846,8 +1846,8 @@ static void check_graph_port(struct check *c, struct dt_info *dti,
 
 	check_graph_reg(c, dti, node);
 
-	/* skip checks below for overlays */
-	if (dti->dtsflags & DTSF_PLUGIN)
+	/* skip checks below for overlays or addons */
+	if (dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON))
 		return;
 
 	if (!strprefixeq(node->name, node->basenamelen, "port"))
@@ -1888,8 +1888,8 @@ static void check_graph_endpoint(struct check *c, struct dt_info *dti,
 
 	check_graph_reg(c, dti, node);
 
-	/* skip checks below for overlays */
-	if (dti->dtsflags & DTSF_PLUGIN)
+	/* skip checks below for overlays or addons */
+	if (dti->dtsflags & (DTSF_PLUGIN | DTSF_ADDON))
 		return;
 
 	if (!strprefixeq(node->name, node->basenamelen, "endpoint"))
@@ -2062,6 +2062,16 @@ void process_checks(bool force, struct dt_info *dti)
 	unsigned int i;
 	int error = 0;
 
+	if ((dti->dtsflags & (DTSF_ADDON | DTSF_PLUGIN)) == (DTSF_ADDON | DTSF_PLUGIN)) {
+		/*
+		 * Addons and overlays are mutually exclusive. The same input
+		 * cannot be both.
+		 */
+		fprintf(stderr,
+			"ERROR: Input tree cannot be both an addon and an overlay\n");
+		exit(2);
+	}
+
 	for (i = 0; i < ARRAY_SIZE(check_table); i++) {
 		struct check *c = check_table[i];
 
diff --git a/dtc-lexer.l b/dtc-lexer.l
index 1b129b11..7e9b6796 100644
--- a/dtc-lexer.l
+++ b/dtc-lexer.l
@@ -108,6 +108,11 @@ static void PRINTF(1, 2) lexical_error(const char *fmt, ...);
 			return DT_PLUGIN;
 		}
 
+<*>"/addon/"	{
+			DPRINT("Keyword: /addon/\n");
+			return DT_ADDON;
+		}
+
 <*>"/memreserve/"	{
 			DPRINT("Keyword: /memreserve/\n");
 			BEGIN_DEFAULT();
diff --git a/dtc-parser.y b/dtc-parser.y
index e47f80d4..2e152b0e 100644
--- a/dtc-parser.y
+++ b/dtc-parser.y
@@ -53,6 +53,7 @@ static bool is_ref_relative(const char *ref)
 
 %token DT_V1
 %token DT_PLUGIN
+%token DT_ADDON
 %token DT_MEMRESERVE
 %token DT_LSHIFT DT_RSHIFT DT_LE DT_GE DT_EQ DT_NE DT_AND DT_OR
 %token DT_BITS
@@ -120,6 +121,10 @@ header:
 		{
 			$$ = DTSF_V1 | DTSF_PLUGIN;
 		}
+	| DT_V1 ';' DT_ADDON ';'
+		{
+			$$ = DTSF_V1 | DTSF_ADDON;
+		}
 	;
 
 headers:
diff --git a/dtc.h b/dtc.h
index 64eaffde..40aab572 100644
--- a/dtc.h
+++ b/dtc.h
@@ -336,6 +336,7 @@ struct dt_info {
 /* DTS version flags definitions */
 #define DTSF_V1		0x0001	/* /dts-v1/ */
 #define DTSF_PLUGIN	0x0002	/* /plugin/ */
+#define DTSF_ADDON	0x0004	/* /addon/ */
 
 struct dt_info *build_dt_info(unsigned int dtsflags,
 			      struct reserve_info *reservelist,
diff --git a/fdtdump.c b/fdtdump.c
index 2acf3210..370db848 100644
--- a/fdtdump.c
+++ b/fdtdump.c
@@ -120,6 +120,10 @@ static void dump_blob(void *blob, bool debug, int dump_unknown)
 		printf("// last_comp_version_w:\t%"PRIu32"\n",
 		       fdt32_to_cpu(bph->last_comp_version_w));
 	}
+	if (version >= 18) {
+		if (fdt32_to_cpu(bph->dt_flags) & FDT_FLAG_ADDON)
+			printf("/addon/;\n");
+	}
 	printf("\n");
 
 	for (i = 0; ; i++) {
diff --git a/flattree.c b/flattree.c
index abc50873..004119c4 100644
--- a/flattree.c
+++ b/flattree.c
@@ -420,6 +420,7 @@ void dt_to_blob(FILE *f, struct dt_info *dti, int version)
 	struct data dtbuf      = empty_data;
 	struct data strbuf     = empty_data;
 	struct fdt_header fdt;
+	uint32_t dt_flags = 0;
 	int padlen = 0;
 
 	for (i = 0; i < ARRAY_SIZE(version_table); i++) {
@@ -429,6 +430,8 @@ void dt_to_blob(FILE *f, struct dt_info *dti, int version)
 	if (!vi)
 		die("Unknown device tree blob version %d\n", version);
 
+	dt_flags |= dti->dtsflags & DTSF_ADDON ? FDT_FLAG_ADDON : 0;
+
 	flatten_tree(dti->dt, &bin_emitter, &dtbuf, &strbuf, vi);
 	bin_emit_cell(&dtbuf, FDT_END);
 
@@ -436,7 +439,7 @@ void dt_to_blob(FILE *f, struct dt_info *dti, int version)
 
 	/* Make header */
 	make_fdt_header(&fdt, vi, reservebuf.len, dtbuf.len, strbuf.len,
-			dti->boot_cpuid_phys, 0);
+			dti->boot_cpuid_phys, dt_flags);
 
 	/*
 	 * If the user asked for more space than is used, adjust the totalsize.
@@ -519,6 +522,7 @@ void dt_to_asm(FILE *f, struct dt_info *dti, int version)
 	struct data strbuf = empty_data;
 	struct reserve_info *re;
 	const char *symprefix = "dt";
+	uint32_t dt_flags = 0;
 
 	for (i = 0; i < ARRAY_SIZE(version_table); i++) {
 		if (version_table[i].version == version)
@@ -527,6 +531,8 @@ void dt_to_asm(FILE *f, struct dt_info *dti, int version)
 	if (!vi)
 		die("Unknown device tree blob version %d\n", version);
 
+	dt_flags |= dti->dtsflags & DTSF_ADDON ? FDT_FLAG_ADDON : 0;
+
 	fprintf(f, "/* autogenerated by dtc, do not edit */\n\n");
 
 	emit_label(f, symprefix, "blob_start");
@@ -569,7 +575,7 @@ void dt_to_asm(FILE *f, struct dt_info *dti, int version)
 
 	if (vi->flags & FTF_DTFLAGS) {
 		fprintf(f, "\t/* dt_flags */\n");
-		asm_emit_cell(f, 0);
+		asm_emit_cell(f, dt_flags);
 	}
 
 	if (vi->flags & FTF_LCVERSW) {
@@ -1113,8 +1119,11 @@ struct dt_info *dt_from_blob(const char *fname)
 	if (version >= 18)
 		flags |= FTF_DTFLAGS | FTF_LCVERSW;
 
-	if (version >= 20)
+	if (version >= 20) {
 		flags |= FTF_PROPDATA_PHANDLE;
+		dtsflags |= fdt32_to_cpu(fdt->dt_flags) & FDT_FLAG_ADDON ?
+				DTSF_ADDON : 0;
+	}
 
 	inbuf_init(&memresvbuf,
 		   blob + off_mem_rsvmap, blob + totalsize);
diff --git a/libfdt/fdt.h b/libfdt/fdt.h
index c151aa2b..255e9447 100644
--- a/libfdt/fdt.h
+++ b/libfdt/fdt.h
@@ -52,6 +52,7 @@ struct fdt_property {
 #endif /* !__ASSEMBLER__ */
 
 #define FDT_MAGIC	0xd00dfeed	/* 4: version, 4: total size */
+#define FDT_FLAG_ADDON  0x1
 #define FDT_TAGSIZE	sizeof(fdt32_t)
 #define FDT_CELLSIZE	sizeof(fdt32_t)
 
diff --git a/treesource.c b/treesource.c
index 0e33e3e1..9f6cf92d 100644
--- a/treesource.c
+++ b/treesource.c
@@ -420,8 +420,14 @@ void dt_to_source(FILE *f, struct dt_info *dti)
 	struct reserve_info *re;
 
 	fprintf(f, "/dts-v1/;\n");
+	/*
+	 * DTSF_PLUGIN and DTSF_ADDON are mutually exclusive. This has been
+	 * already checked.
+	 */
 	if (dti->dtsflags & DTSF_PLUGIN)
 		fprintf(f, "/plugin/;\n");
+	if (dti->dtsflags & DTSF_ADDON)
+		fprintf(f, "/addon/;\n");
 	fprintf(f, "\n");
 
 	for (re = dti->reservelist; re; re = re->next) {
-- 
2.55.0