Fix OF_finddevice error return value in case of FDT.

According to the open firmware standard, finddevice call has to return
a phandle with value of -1 in case of error.

This commit is to:
- Fix the FDT implementation of this interface (ofw_fdt_finddevice) to
  return (phandle_t)-1 in case of error, instead of 0 as it does now.
- Fix up the callers of OF_finddevice() to compare the return value with
  -1 instead of 0 to check for errors.
- Since phandle_t is unsigned, the return value of OF_finddevice should
  be checked with '== -1' rather than '<= 0' or '> 0', fix up these cases
  as well.

Reported by:	nwhitehorn

Reviewed by:	raj
Approved by:	raj, nwhitehorn

6 files changed, 11 insertions, 9 deletions

diff --git a/sys/dev/fdt/fdt_common.c b/sys/dev/fdt/fdt_common.c
index d25715b..8702df2 100644
--- a/sys/dev/fdt/fdt_common.c
+++ b/sys/dev/fdt/fdt_common.c
@@ -74,13 +74,13 @@ fdt_immr_addr(vm_offset_t immr_va)
 	/*
 	 * Try to access the SOC node directly i.e. through /aliases/.
 	 */
-	if ((node = OF_finddevice("soc")) != 0)
+	if ((node = OF_finddevice("soc")) != -1)
 		if (fdt_is_compatible_strict(node, "simple-bus"))
 			goto moveon;
 	/*
 	 * Find the node the long way.
 	 */
-	if ((node = OF_finddevice("/")) == 0)
+	if ((node = OF_finddevice("/")) == -1)
 		return (ENXIO);
 
 	if ((node = fdt_find_compatible(node, "simple-bus", 1)) == 0)
@@ -576,7 +576,7 @@ fdt_get_mem_regions(struct mem_region *mr, int *mrcnt, uint32_t *memsize)
 
 	max_size = sizeof(reg);
 	memory = OF_finddevice("/memory");
-	if (memory <= 0) {
+	if (memory == -1) {
 		rv = ENXIO;
 		goto out;
 	}
diff --git a/sys/dev/fdt/fdt_powerpc.c b/sys/dev/fdt/fdt_powerpc.c
index ea614db..ac81c08 100644
--- a/sys/dev/fdt/fdt_powerpc.c
+++ b/sys/dev/fdt/fdt_powerpc.c
@@ -62,7 +62,7 @@ fdt_fixup_busfreq(phandle_t root)
 	 * This fixup uses /cpus/ bus-frequency prop value to set simple-bus
 	 * bus-frequency property.
 	 */
-	if ((cpus = OF_finddevice("/cpus")) == 0)
+	if ((cpus = OF_finddevice("/cpus")) == -1)
 		return;
 
 	if ((child = OF_child(cpus)) == 0)
diff --git a/sys/dev/fdt/fdtbus.c b/sys/dev/fdt/fdtbus.c
index a2530cd..50db7cd 100644
--- a/sys/dev/fdt/fdtbus.c
+++ b/sys/dev/fdt/fdtbus.c
@@ -177,7 +177,7 @@ fdtbus_attach(device_t dev)
 	u_long start, end;
 	int error;
 
-	if ((root = OF_peer(0)) == 0)
+	if ((root = OF_finddevice("/")) == -1)
 		panic("fdtbus_attach: no root node.");
 
 	sc = device_get_softc(dev);
diff --git a/sys/dev/ofw/ofw_fdt.c b/sys/dev/ofw/ofw_fdt.c
index 806f17c..7b3b0e9 100644
--- a/sys/dev/ofw/ofw_fdt.c
+++ b/sys/dev/ofw/ofw_fdt.c
@@ -392,6 +392,8 @@ ofw_fdt_finddevice(ofw_t ofw, const char *device)
 	int offset;
 
 	offset = fdt_path_offset(fdtp, device);
+	if (offset < 0)
+		return (-1);
 	return (fdt_offset_phandle(offset));
 }
 
@@ -420,7 +422,7 @@ ofw_fdt_fixup(ofw_t ofw)
 	ssize_t len;
 	int i;
 
-	if ((root = ofw_fdt_finddevice(ofw, "/")) == 0)
+	if ((root = ofw_fdt_finddevice(ofw, "/")) == -1)
 		return (ENODEV);
 
 	if ((len = ofw_fdt_getproplen(ofw, root, "model")) <= 0)
diff --git a/sys/dev/ofw/openfirm.c b/sys/dev/ofw/openfirm.c
index 9ff72df..af6ee80 100644
--- a/sys/dev/ofw/openfirm.c
+++ b/sys/dev/ofw/openfirm.c
@@ -131,7 +131,7 @@ OF_init(void *cookie)
 
 	rv = OFW_INIT(ofw_obj, cookie);
 
-	if ((chosen = OF_finddevice("/chosen")) > 0)
+	if ((chosen = OF_finddevice("/chosen")) != -1)
 		if (OF_getprop(chosen, "stdout", &stdout, sizeof(stdout)) == -1)
 			stdout = -1;
 
diff --git a/sys/dev/uart/uart_bus_fdt.c b/sys/dev/uart/uart_bus_fdt.c
index f8204b1..8088db4 100644
--- a/sys/dev/uart/uart_bus_fdt.c
+++ b/sys/dev/uart/uart_bus_fdt.c
@@ -155,11 +155,11 @@ uart_cpu_getdev(int devtype, struct uart_devinfo *di)
 	/*
 	 * Retrieve /chosen/std{in,out}.
 	 */
-	if ((chosen = OF_finddevice("/chosen")) == 0)
+	if ((chosen = OF_finddevice("/chosen")) == -1)
 		return (ENXIO);
 	if (OF_getprop(chosen, "stdin", buf, sizeof(buf)) <= 0)
 		return (ENXIO);
-	if ((node = OF_finddevice(buf)) == 0)
+	if ((node = OF_finddevice(buf)) == -1)
 		return (ENXIO);
 	if (OF_getprop(chosen, "stdout", buf, sizeof(buf)) <= 0)
 		return (ENXIO);