[PATCH 1/4] PBL: fdt: implement fdt_device_get_match_data

[Ahmad Fatoum]

Currently, the generic DT image can't properly have a PBL console,
because it's only known at runtime what system we are running on.

As we already parse the FDT in the PBL to get the memory regions, we
could extract the board compatible as well and determine which UART to
use. Add a helper to achieve this.

Signed-off-by: Ahmad Fatoum <ahmad at a3f.at>
---
 include/pbl.h |  9 +++++++++
 pbl/fdt.c     | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/include/pbl.h b/include/pbl.h
index 194d5e750839..f58daec7351a 100644
--- a/include/pbl.h
+++ b/include/pbl.h
@@ -34,4 +34,13 @@ ssize_t pbl_fat_load(struct pbl_bio *, const char *filename, void *dest, size_t
 
 void fdt_find_mem(const void *fdt, unsigned long *membase, unsigned long *memsize);
 
+struct fdt_device_id {
+	const char *compatible;
+	const void *data;
+};
+
+const void *
+fdt_device_get_match_data(const void *fdt, const char *nodepath,
+			  const struct fdt_device_id ids[]);
+
 #endif /* __PBL_H__ */
diff --git a/pbl/fdt.c b/pbl/fdt.c
index b4a40a514b8b..03260cb61971 100644
--- a/pbl/fdt.c
+++ b/pbl/fdt.c
@@ -68,3 +68,39 @@ err:
 	pr_err("No memory, cannot continue\n");
 	while (1);
 }
+
+const void *fdt_device_get_match_data(const void *fdt, const char *nodepath,
+				      const struct fdt_device_id ids[])
+{
+	int node, length;
+	const char *list, *end;
+	const struct fdt_device_id *id;
+
+	node = fdt_path_offset(fdt, nodepath);
+	if (node < 0)
+		return NULL;
+
+	list = fdt_getprop(fdt, node, "compatible", &length);
+	if (!list)
+		return NULL;
+
+	end = list + length;
+
+	while (list < end) {
+		length = strnlen(list, end - list) + 1;
+
+		/* Abort if the last string isn't properly NUL-terminated. */
+		if (list + length > end)
+			return NULL;
+
+		for (id = ids; id->compatible; id++) {
+			if (strlen(id->compatible) == length &&
+			    !memcmp(list, id->compatible, length))
+				return id->data;
+		}
+
+		list += length;
+	}
+
+	return NULL;
+}
-- 
2.30.0