[fdt] Use phandle as device location

Consumption of phandles will be in the form of locating a functional
device (e.g. a GPIO device, or an I2C device, or a reset controller)
by phandle, rather than locating the device tree node to which the
phandle refers.

Repurpose fdt_phandle() to obtain the phandle value (instead of
searching by phandle), and record this value as the bus location
within the generic device structure.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/fdt.c

@@ -482,57 +482,6 @@ int fdt_alias ( struct fdt *fdt, const char *name, unsigned int *offset ) {
 	return 0;
 }
 
-/**
- * Find node by package handle (phandle)
- *
- * @v fdt		Device tree
- * @v phandle		Package handle
- * @v offset		Offset to fill in
- * @ret rc		Return status code
- */
-int fdt_phandle ( struct fdt *fdt, uint32_t phandle, unsigned int *offset ) {
-	struct fdt_descriptor desc;
-	uint32_t value;
-	int depth;
-	int rc;
-
-	/* Initialise offset */
-	*offset = 0;
-
-	/* Find node with matching phandle */
-	for ( depth = -1 ; ; depth += desc.depth, *offset = desc.next ) {
-
-		/* Describe token */
-		if ( ( rc = fdt_describe ( fdt, *offset, &desc ) ) != 0 ) {
-			DBGC ( fdt, "FDT +%#04x has malformed node: %s\n",
-			       *offset, strerror ( rc ) );
-			return rc;
-		}
-
-		/* Terminate when we exit the root node */
-		if ( ( depth == 0 ) && ( desc.depth < 0 ) )
-			break;
-
-		/* Ignore non-nodes */
-		if ( ( ! desc.name ) || desc.data )
-			continue;
-
-		/* Check for matching "phandle" or "linux-phandle" property */
-		if ( ( ( ( rc = fdt_u32 ( fdt, *offset, "phandle",
-					  &value ) ) == 0 ) ||
-		       ( ( rc = fdt_u32 ( fdt, *offset, "linux,phandle",
-					  &value ) ) == 0 ) ) &&
-		     ( value == phandle ) ) {
-			DBGC2 ( fdt, "FDT +%#04x has phandle %#02x\n",
-				*offset, phandle );
-			return 0;
-		}
-	}
-
-	DBGC ( fdt, "FDT has no phandle %#02x\n", phandle );
-	return -ENOENT;
-}
-
 /**
  * Find property
  *
@@ -730,6 +679,28 @@ int fdt_u32 ( struct fdt *fdt, unsigned int offset, const char *name,
 	return 0;
 }
 
+/**
+ * Get package handle (phandle) property
+ *
+ * @v fdt		Device tree
+ * @v offset		Starting node offset
+ * @ret phandle		Package handle, or 0 on error
+ */
+uint32_t fdt_phandle ( struct fdt *fdt, unsigned int offset ) {
+	uint32_t phandle;
+	int rc;
+
+	/* Get "phandle" or "linux,phandle" property */
+	if ( ( ( rc = fdt_u32 ( fdt, offset, "phandle", &phandle ) ) == 0 ) ||
+	     ( ( rc = fdt_u32 ( fdt, offset, "linux,phandle",
+				&phandle ) ) == 0 ) ) {
+		assert ( phandle != 0 );
+		return phandle;
+	}
+
+	return 0;
+}
+
 /**
  * Get region cell size specification
  *

src/drivers/bus/devtree.c

@@ -219,6 +219,7 @@ int dt_probe_node ( struct device *parent, unsigned int offset ) {
 	dt->name = dt->dev.name;
 	snprintf ( dt->dev.name, sizeof ( dt->dev.name ), "%s", name );
 	dt->dev.desc.bus_type = BUS_TYPE_DT;
+	dt->dev.desc.location = fdt_phandle ( &sysfdt, offset );
 	dt->dev.parent = parent;
 	INIT_LIST_HEAD ( &dt->dev.children );
 	list_add_tail ( &dt->dev.siblings, &parent->children );

src/include/ipxe/fdt.h

@@ -176,8 +176,6 @@ extern int fdt_path ( struct fdt *fdt, const char *path,
 		      unsigned int *offset );
 extern int fdt_alias ( struct fdt *fdt, const char *name,
 		       unsigned int *offset );
-extern int fdt_phandle ( struct fdt *fdt, uint32_t phandle,
-			 unsigned int *offset );
 extern const char * fdt_strings ( struct fdt *fdt, unsigned int offset,
 				  const char *name, unsigned int *count );
 extern const char * fdt_string ( struct fdt *fdt, unsigned int offset,
@@ -189,6 +187,7 @@ extern int fdt_u64 ( struct fdt *fdt, unsigned int offset, const char *name,
 		     uint64_t *value );
 extern int fdt_u32 ( struct fdt *fdt, unsigned int offset, const char *name,
 		     uint32_t *value );
+extern uint32_t fdt_phandle ( struct fdt *fdt, unsigned int offset );
 extern void fdt_reg_cells ( struct fdt *fdt, unsigned int offset,
 			    struct fdt_reg_cells *regs );
 extern int fdt_reg_count ( struct fdt *fdt, unsigned int offset,

src/tests/fdt_test.c

@@ -237,6 +237,16 @@ static void fdt_test_exec ( void ) {
 	ok ( fdt_path ( &fdt, "/soc/ethernet@10090000", &offset ) == 0 );
 	ok ( fdt_u32 ( &fdt, offset, "max-speed", &u32 ) != 0 );
 
+	/* Verify phandle properties */
+	ok ( fdt_path ( &fdt, "/cpus/cpu@0/interrupt-controller",
+			&offset ) == 0 );
+	ok ( fdt_phandle ( &fdt, offset ) == 0x03 );
+	ok ( fdt_path ( &fdt, "/soc/ethernet@10090000/ethernet-phy@0",
+			&offset ) == 0 );
+	ok ( fdt_phandle ( &fdt, offset ) == 0x08 );
+	ok ( fdt_path ( &fdt, "/soc/serial@10010000", &offset ) == 0 );
+	ok ( fdt_phandle ( &fdt, offset ) == 0 );
+
 	/* Verify cell properties */
 	ok ( fdt_path ( &fdt, "/soc/ethernet@10090000", &offset ) == 0 );
 	ok ( fdt_cells ( &fdt, offset, "reg", 4, 2, &u64 ) == 0 );
@@ -261,15 +271,6 @@ static void fdt_test_exec ( void ) {
 	ok ( ( string = fdt_string ( &fdt, offset, "phy-mode" ) ) != NULL );
 	ok ( strcmp ( string, "gmii" ) == 0 );
 
-	/* Verify phandle lookup */
-	ok ( fdt_phandle ( &fdt, 0x03, &offset ) == 0 );
-	ok ( fdt_describe ( &fdt, offset, &desc ) == 0 );
-	ok ( strcmp ( desc.name, "interrupt-controller" ) == 0 );
-	ok ( fdt_phandle ( &fdt, 0x08, &offset ) == 0 );
-	ok ( fdt_describe ( &fdt, offset, &desc ) == 0 );
-	ok ( strcmp ( desc.name, "ethernet-phy@0" ) == 0 );
-	ok ( fdt_phandle ( &fdt, 0x2a, &offset ) != 0 );
-
 	/* Verify node description */
 	ok ( fdt_path ( &fdt, "/memory@80000000", &offset ) == 0 );
 	ok ( fdt_describe ( &fdt, offset, &desc ) == 0 );