PBL: fdt: implement fdt_device_get_match_data

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@a3f.at>
Link: https://lore.barebox.org/20210410110638.2106658-1-ahmad@a3f.at
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

2 files changed, 47 insertions, 0 deletions

diff --git a/pbl/fdt.c b/pbl/fdt.c
index b4a40a514b..18ddb9f48a 100644
--- a/pbl/fdt.c
+++ b/pbl/fdt.c
@@ -68,3 +68,38 @@ 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 (!strcasecmp(list, id->compatible))
+				return id->data;
+		}
+
+		list += length;
+	}
+
+	return NULL;
+}
diff --git a/pbl/string.c b/pbl/string.c
index e6c0997ebc..e96eb99fc2 100644
--- a/pbl/string.c
+++ b/pbl/string.c
@@ -7,6 +7,7 @@
 #include <linux/types.h>
 #include <linux/string.h>
 #include <linux/compiler.h>
+#include <linux/ctype.h>
 
 void *memcpy(void *__dest, __const void *__src, size_t __n)
 {
@@ -98,6 +99,17 @@ int strcmp(const char *cs, const char *ct)
 	return res;
 }
 
+int strcasecmp(const char *s1, const char *s2)
+{
+	int c1, c2;
+
+	do {
+		c1 = tolower(*s1++);
+		c2 = tolower(*s2++);
+	} while (c1 == c2 && c1 != 0);
+	return c1 - c2;
+}
+
 void *memchr(const void *s, int c, size_t count)
 {
 	const unsigned char *p = s;