[PATCH v2] ppc/vof: Make nextprop behave more like Open Firmware

[BALATON Zoltan <balaton@eik.bme.hu>]

The FDT does not normally store name properties but reconstructs it
from path but each node in Open Firmware should at least have this
property. This is correctly handled in getprop but nextprop should
also return it even if not present as a property. This patch fixes
that and also skips phandle which does not appear in Open Firmware
and only added for internal use by VOF.

Explicit name properties are still allowed because they are needed
e.g. on the root node that guests expect to have specific names as
seen on real machines instead of being empty so sometimes the node
name may need to be overriden.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
---
I've tested this with pegasos2 but don't know how to test spapr.
v2:
Fixed a typo in commit message
Simplified loop to get next property name

 hw/ppc/vof.c | 51 ++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/hw/ppc/vof.c b/hw/ppc/vof.c
index 09cb77de93..790d67c096 100644
--- a/hw/ppc/vof.c
+++ b/hw/ppc/vof.c
@@ -353,34 +353,51 @@ static uint32_t vof_nextprop(const void *fdt, uint32_t phandle,
 {
     int offset, nodeoff = fdt_node_offset_by_phandle(fdt, phandle);
     char prev[OF_PROPNAME_LEN_MAX + 1];
-    const char *tmp;
+    const char *tmp = NULL;
+    bool match = false;
 
     if (readstr(prevaddr, prev, sizeof(prev))) {
         return PROM_ERROR;
     }
-
-    fdt_for_each_property_offset(offset, fdt, nodeoff) {
-        if (!fdt_getprop_by_offset(fdt, offset, &tmp, NULL)) {
-            return 0;
+    /*
+     * "name" may or may not be present in fdt but we should still return it.
+     * Do that first and then skip it if seen later. Also skip phandle which is
+     * an internal value we added in vof_build_dt but should not appear here.
+     */
+    if (prev[0] == '\0') {
+        tmp = "name";
+    } else {
+        if (strcmp(prev, "name") == 0) {
+            prev[0] = '\0';
         }
-        if (prev[0] == '\0' || strcmp(prev, tmp) == 0) {
-            if (prev[0] != '\0') {
-                offset = fdt_next_property_offset(fdt, offset);
-                if (offset < 0) {
-                    return 0;
-                }
-            }
+        fdt_for_each_property_offset(offset, fdt, nodeoff) {
             if (!fdt_getprop_by_offset(fdt, offset, &tmp, NULL)) {
                 return 0;
             }
-
-            if (VOF_MEM_WRITE(nameaddr, tmp, strlen(tmp) + 1) != MEMTX_OK) {
-                return PROM_ERROR;
+            if (strcmp(tmp, "name") == 0 || strcmp(tmp, "phandle") == 0) {
+                continue;
+            }
+            if (match) {
+                break;
             }
-            return 1;
+            if (strcmp(prev, tmp) == 0) {
+                match = true;
+                continue;
+            }
+            if (prev[0] == '\0') {
+                break;
+            }
+        }
+        if (offset < 0) {
+            return 0;
         }
     }
-
+    if (tmp) {
+        if (VOF_MEM_WRITE(nameaddr, tmp, strlen(tmp) + 1) != MEMTX_OK) {
+            return PROM_ERROR;
+        }
+        return 1;
+    }
     return 0;
 }
 
-- 
2.41.3