stand/ofw: Add ofw_path_to_handle

ofw_path_to_handle converts a path string to a phandle_t. It searches
down the path for the first device whose type matches the passed-in
string.

Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D37556

(cherry picked from commit ed3cc2f24829e6c5827f142cfcd9729331a1106c)

2 files changed, 35 insertions, 0 deletions

diff --git a/stand/libofw/devicename.c b/stand/libofw/devicename.c
index ecf966506194..6ed2343ee7bd 100644
--- a/stand/libofw/devicename.c
+++ b/stand/libofw/devicename.c
@@ -63,6 +63,38 @@ ofw_getdev(void **vdev, const char *devspec, const char **path)
 }
 
 /*
+ * Search the OFW (path) for a node that's of (want_type).
+ */
+phandle_t
+ofw_path_to_handle(const char *ofwpath, const char *want_type, const char **path)
+{
+	const char *p, *s;
+	char name[256];
+	char type[64];
+	phandle_t handle;
+	int len;
+
+	for (p = s = ofwpath; *s != '\0'; p = s) {
+		if ((s = strchr(p + 1, '/')) == NULL)
+			s = strchr(p, '\0');
+		len = s - ofwpath;
+		if (len >= sizeof(name))
+			return ((phandle_t)-1);
+		bcopy(ofwpath, name, len);
+		name[len] = '\0';
+		if ((handle = OF_finddevice(name)) == -1)
+			continue;
+		if (OF_getprop(handle, "device_type", type, sizeof(type)) == -1)
+			continue;
+		if (strcmp(want_type, type) == 0) {
+			*path = s;
+			return (handle);
+		}
+	}
+	return ((phandle_t)-1);
+}
+
+/*
  * Point (dev) at an allocated device specifier matching the string version
  * at the beginning of (devspec).  Return a pointer to the remaining
  * text in (path).
@@ -82,6 +114,7 @@ ofw_parsedev(struct ofw_devdesc **dev, const char *devspec, const char **path)
     int			len;
     int			i;
 
+    /* XXX next step: use devparse -- don't forget to hack ofw_disk like you did ofw_net */
     for (p = s = devspec; *s != '\0'; p = s) {
 	if ((s = strchr(p + 1, '/')) == NULL)
 	    s = strchr(p, '\0');
diff --git a/stand/libofw/libofw.h b/stand/libofw/libofw.h
index 59c7ec1fa6b7..0494a78135e7 100644
--- a/stand/libofw/libofw.h
+++ b/stand/libofw/libofw.h
@@ -61,6 +61,8 @@ extern int	ofw_autoload(void);
 
 void	ofw_memmap(int);
 
+phandle_t ofw_path_to_handle(const char *ofwpath, const char *want_type, const char **path);
+
 struct preloaded_file;
 struct file_format;