PKGBUILDs/alarm/dtc-overlay/0002-dtc-Plugin-object-device-tree-support.patch

From b29e0699719c15866ce92af0598b2d61418fe89b Mon Sep 17 00:00:00 2001
From: Pantelis Antoniou
 <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
Date: Tue, 21 Oct 2014 22:39:58 +0300
Subject: [PATCH 2/3] dtc: Plugin (object) device tree support.

Enables the generation of a __fixups__ node for trees compiled
using the -@ option that are using the /plugin/ tag.

The __fixups__ node make possible the dynamic resolution of phandle
references which are present in the plugin tree but lie in the
tree that are applying the overlay against.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
---
 Documentation/manual.txt |  5 ++++
 checks.c                 | 45 ++++++++++++++++++++++++++++++++--
 dtc-lexer.l              |  5 ++++
 dtc-parser.y             | 22 ++++++++++++++---
 dtc.h                    | 12 +++++++++
 flattree.c               | 63 ++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 147 insertions(+), 5 deletions(-)

diff --git a/Documentation/manual.txt b/Documentation/manual.txt
index 4359958..18d1333 100644
--- a/Documentation/manual.txt
+++ b/Documentation/manual.txt
@@ -124,6 +124,9 @@ Options:
 	for any node labels used, and for any local references using phandles
 	it also generates a __local_fixups__ node that tracks them.
 
+	When using the /plugin/ tag all unresolved label references to
+	be tracked in the __fixups__ node, making dynamic resolution possible.
+
     -S <bytes>
 	Ensure the blob at least <bytes> long, adding additional
 	space if needed.
@@ -158,6 +161,8 @@ Here is a very rough overview of the layout of a DTS source file:
 
     devicetree:   '/' nodedef
 
+    plugindecl:   '/' 'plugin' '/' ';'
+
     nodedef:      '{' list_of_property list_of_subnode '}' ';'
 
     property:     label PROPNAME '=' propdata ';'
diff --git a/checks.c b/checks.c
index f203986..2778e89 100644
--- a/checks.c
+++ b/checks.c
@@ -457,6 +457,7 @@ static void fixup_phandle_references(struct check *c, struct node *dt,
 				     struct node *node, struct property *prop)
 {
 	struct marker *m = prop->val.markers;
+	struct fixup *f, **fp;
 	struct fixup_entry *fe, **fep;
 	struct node *refnode;
 	cell_t phandle;
@@ -466,8 +467,48 @@ static void fixup_phandle_references(struct check *c, struct node *dt,
 
 		refnode = get_node_by_ref(dt, m->ref);
 		if (! refnode) {
-			FAIL(c, "Reference to non-existent node or label \"%s\"\n",
-			     m->ref);
+			if (!dt->is_plugin) {
+				FAIL(c, "Reference to non-existent node or label \"%s\"\n",
+					m->ref);
+				continue;
+			}
+
+			/* allocate fixup entry */
+			fe = xmalloc(sizeof(*fe));
+
+			fe->node = node;
+			fe->prop = prop;
+			fe->offset = m->offset;
+			fe->next = NULL;
+
+			/* search for an already existing fixup */
+			for_each_fixup(dt, f)
+				if (strcmp(f->ref, m->ref) == 0)
+					break;
+
+			/* no fixup found, add new */
+			if (f == NULL) {
+				f = xmalloc(sizeof(*f));
+				f->ref = m->ref;
+				f->entries = NULL;
+				f->next = NULL;
+
+				/* add it to the tree */
+				fp = &dt->fixups;
+				while (*fp)
+					fp = &(*fp)->next;
+				*fp = f;
+			}
+
+			/* and now append fixup entry */
+			fep = &f->entries;
+			while (*fep)
+				fep = &(*fep)->next;
+			*fep = fe;
+
+			/* mark the entry as unresolved */
+			*((cell_t *)(prop->val.val + m->offset)) =
+				cpu_to_fdt32(0xdeadbeef);
 			continue;
 		}
 
diff --git a/dtc-lexer.l b/dtc-lexer.l
index 0ee1caf..dd44ba2 100644
--- a/dtc-lexer.l
+++ b/dtc-lexer.l
@@ -113,6 +113,11 @@ static void lexical_error(const char *fmt, ...);
 			return DT_V1;
 		}
 
+<*>"/plugin/"	{
+			DPRINT("Keyword: /plugin/\n");
+			return DT_PLUGIN;
+		}
+
 <*>"/memreserve/"	{
 			DPRINT("Keyword: /memreserve/\n");
 			BEGIN_DEFAULT();
diff --git a/dtc-parser.y b/dtc-parser.y
index ea57e0a..776fdd5 100644
--- a/dtc-parser.y
+++ b/dtc-parser.y
@@ -19,6 +19,7 @@
  */
 %{
 #include <stdio.h>
+#include <inttypes.h>
 
 #include "dtc.h"
 #include "srcpos.h"
@@ -52,9 +53,11 @@ extern bool treesource_error;
 	struct node *nodelist;
 	struct reserve_info *re;
 	uint64_t integer;
+	bool is_plugin;
 }
 
 %token DT_V1
+%token DT_PLUGIN
 %token DT_MEMRESERVE
 %token DT_LSHIFT DT_RSHIFT DT_LE DT_GE DT_EQ DT_NE DT_AND DT_OR
 %token DT_BITS
@@ -71,6 +74,7 @@ extern bool treesource_error;
 
 %type <data> propdata
 %type <data> propdataprefix
+%type <is_plugin> plugindecl
 %type <re> memreserve
 %type <re> memreserves
 %type <array> arrayprefix
@@ -101,10 +105,22 @@ extern bool treesource_error;
 %%
 
 sourcefile:
-	  DT_V1 ';' memreserves devicetree
+	  DT_V1 ';' plugindecl memreserves devicetree
 		{
-			the_boot_info = build_boot_info($3, $4,
-							guess_boot_cpuid($4));
+			$5->is_plugin = $3;
+			the_boot_info = build_boot_info($4, $5,
+							guess_boot_cpuid($5));
+		}
+	;
+
+plugindecl:
+	/* empty */
+		{
+			$$ = false;
+		}
+	| DT_PLUGIN ';'
+		{
+			$$ = true;
 		}
 	;
 
diff --git a/dtc.h b/dtc.h
index 16354fa..f163b22 100644
--- a/dtc.h
+++ b/dtc.h
@@ -141,6 +141,12 @@ struct fixup_entry {
 	bool local_fixup_generated;
 };
 
+struct fixup {
+	char *ref;
+	struct fixup_entry *entries;
+	struct fixup *next;
+};
+
 struct symbol {
 	struct label *label;
 	struct node *node;
@@ -177,6 +183,9 @@ struct node {
 	struct symbol *symbols;
 	struct fixup_entry *local_fixups;
 	bool emit_local_fixup_node;
+
+	bool is_plugin;
+	struct fixup *fixups;
 };
 
 #define for_each_label_withdel(l0, l) \
@@ -200,6 +209,9 @@ struct node {
 	for_each_child_withdel(n, c) \
 		if (!(c)->deleted)
 
+#define for_each_fixup(n, f) \
+	for ((f) = (n)->fixups; (f); (f) = (f)->next)
+
 #define for_each_fixup_entry(f, fe) \
 	for ((fe) = (f)->entries; (fe); (fe) = (fe)->next)
 
diff --git a/flattree.c b/flattree.c
index 3a58949..2385137 100644
--- a/flattree.c
+++ b/flattree.c
@@ -391,6 +391,68 @@ static void emit_local_fixups_node(struct node *tree, struct emitter *emit,
 	emit->endnode(etarget, tree->labels);
 }
 
+static void emit_fixups_node(struct node *tree, struct emitter *emit,
+			     void *etarget, struct data *strbuf,
+			     struct version_info *vi)
+{
+	struct fixup *f;
+	struct fixup_entry *fe;
+	char *name, *s;
+	const char *fullpath;
+	int namesz, nameoff, vallen;
+
+	/* do nothing if no fixups */
+	if (!tree->fixups)
+		return;
+
+	/* emit the external fixups */
+	emit->beginnode(etarget, NULL);
+	emit->string(etarget, "__fixups__", 0);
+	emit->align(etarget, sizeof(cell_t));
+
+	for_each_fixup(tree, f) {
+
+		namesz = 0;
+		for_each_fixup_entry(f, fe) {
+			fullpath = fe->node->fullpath;
+			if (fullpath[0] == '\0')
+				fullpath = "/";
+			namesz += strlen(fullpath) + 1;
+			namesz += strlen(fe->prop->name) + 1;
+			namesz += 32;	/* space for :<number> + '\0' */
+		}
+
+		name = xmalloc(namesz);
+
+		s = name;
+		for_each_fixup_entry(f, fe) {
+			fullpath = fe->node->fullpath;
+			if (fullpath[0] == '\0')
+				fullpath = "/";
+			snprintf(s, name + namesz - s, "%s:%s:%d", fullpath,
+					fe->prop->name, fe->offset);
+			s += strlen(s) + 1;
+		}
+
+		nameoff = stringtable_insert(strbuf, f->ref);
+		vallen = s - name - 1;
+
+		emit->property(etarget, NULL);
+		emit->cell(etarget, vallen + 1);
+		emit->cell(etarget, nameoff);
+
+		if ((vi->flags & FTF_VARALIGN) && vallen >= 8)
+			emit->align(etarget, 8);
+
+		emit->string(etarget, name, vallen);
+		emit->align(etarget, sizeof(cell_t));
+
+		free(name);
+	}
+
+	emit->endnode(etarget, tree->labels);
+}
+
 static void flatten_tree(struct node *tree, struct emitter *emit,
 			 void *etarget, struct data *strbuf,
 			 struct version_info *vi)
@@ -448,6 +510,7 @@ static void flatten_tree(struct node *tree, struct emitter *emit,
 
 	emit_symbols_node(tree, emit, etarget, strbuf, vi);
 	emit_local_fixups_node(tree, emit, etarget, strbuf, vi);
+	emit_fixups_node(tree, emit, etarget, strbuf, vi);
 
 	emit->endnode(etarget, tree->labels);
 }
-- 
2.2.2