[PATCH 01/27] system/device_tree: update qemu_fdt_getprop/_cell

[Ruslan Ruslichenko <ruslichenko.r@gmail.com>]

From: Ruslan Ruslichenko <Ruslan_Ruslichenko@epam.com>

Update 'qemu_fdt_getprop' and 'qemu_fdt_getprop_cell'
to support property inheritence from parent node,
in case 'inherit' argument is set.

Update 'qemu_fdt_getprop_cell' to allow accessing
specific cells within multi-cell property array.

Introduced 'qemu_devtreedd_getparent' as it is needed
by both internal and external users.

This will be used by hardware device tree parsing logic.

Signed-off-by: Ruslan Ruslichenko <Ruslan_Ruslichenko@epam.com>
---
 hw/arm/boot.c                |  8 ++++----
 hw/arm/raspi4b.c             |  8 ++++----
 hw/arm/vexpress.c            |  4 ++--
 hw/arm/xlnx-zcu102.c         |  3 ++-
 include/system/device_tree.h | 32 +++++++++++++++++++-------------
 system/device_tree.c         | 33 ++++++++++++++++++++++++---------
 6 files changed, 55 insertions(+), 33 deletions(-)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index c97d4c4e11..829b8ba12f 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -509,10 +509,10 @@ int arm_load_dtb(hwaddr addr, const struct arm_boot_info *binfo,
         return 0;
     }
 
-    acells = qemu_fdt_getprop_cell(fdt, "/", "#address-cells",
-                                   NULL, &error_fatal);
-    scells = qemu_fdt_getprop_cell(fdt, "/", "#size-cells",
-                                   NULL, &error_fatal);
+    acells = qemu_fdt_getprop_cell(fdt, "/", "#address-cells", 0,
+                                   false, &error_fatal);
+    scells = qemu_fdt_getprop_cell(fdt, "/", "#size-cells", 0,
+                                   false, &error_fatal);
     if (acells == 0 || scells == 0) {
         fprintf(stderr, "dtb file invalid (#address-cells or #size-cells 0)\n");
         goto fail;
diff --git a/hw/arm/raspi4b.c b/hw/arm/raspi4b.c
index 3eeb8f447e..66eba5d667 100644
--- a/hw/arm/raspi4b.c
+++ b/hw/arm/raspi4b.c
@@ -42,10 +42,10 @@ static void raspi_add_memory_node(void *fdt, hwaddr mem_base, hwaddr mem_len)
     uint32_t acells, scells;
     char *nodename = g_strdup_printf("/memory@%" PRIx64, mem_base);
 
-    acells = qemu_fdt_getprop_cell(fdt, "/", "#address-cells",
-                                   NULL, &error_fatal);
-    scells = qemu_fdt_getprop_cell(fdt, "/", "#size-cells",
-                                   NULL, &error_fatal);
+    acells = qemu_fdt_getprop_cell(fdt, "/", "#address-cells", 0,
+                                   false, &error_fatal);
+    scells = qemu_fdt_getprop_cell(fdt, "/", "#size-cells", 0,
+                                   false, &error_fatal);
     /* validated by arm_load_dtb */
     g_assert(acells && scells);
 
diff --git a/hw/arm/vexpress.c b/hw/arm/vexpress.c
index cc6ae7d4c4..823e316f91 100644
--- a/hw/arm/vexpress.c
+++ b/hw/arm/vexpress.c
@@ -486,9 +486,9 @@ static void vexpress_modify_dtb(const struct arm_boot_info *info, void *fdt)
     const VEDBoardInfo *daughterboard = (const VEDBoardInfo *)info;
 
     acells = qemu_fdt_getprop_cell(fdt, "/", "#address-cells",
-                                   NULL, &error_fatal);
+                                   0, false, &error_fatal);
     scells = qemu_fdt_getprop_cell(fdt, "/", "#size-cells",
-                                   NULL, &error_fatal);
+                                   0, false, &error_fatal);
     intc = find_int_controller(fdt);
     if (!intc) {
         /* Not fatal, we just won't provide virtio. This will
diff --git a/hw/arm/xlnx-zcu102.c b/hw/arm/xlnx-zcu102.c
index 3ba2736bab..8f67c8be48 100644
--- a/hw/arm/xlnx-zcu102.c
+++ b/hw/arm/xlnx-zcu102.c
@@ -88,7 +88,8 @@ static void zcu102_modify_dtb(const struct arm_boot_info *binfo, void *fdt)
                                        &error_fatal);
 
         for (i = 0; node_path && node_path[i]; i++) {
-            r = qemu_fdt_getprop(fdt, node_path[i], "method", &prop_len, NULL);
+            r = qemu_fdt_getprop(fdt, node_path[i], "method", &prop_len,
+                                 false, NULL);
             method_is_hvc = r && !strcmp("hvc", r);
 
             /* Allow HVC based firmware if EL2 is enabled.  */
diff --git a/include/system/device_tree.h b/include/system/device_tree.h
index 49d8482ed4..f34b8b7ef9 100644
--- a/include/system/device_tree.h
+++ b/include/system/device_tree.h
@@ -96,27 +96,28 @@ int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,
  * @node_path: node path
  * @property: name of the property to find
  * @lenp: fdt error if any or length of the property on success
+ * @inherit: if not found in node, look for property in parent
  * @errp: handle to an error object
  *
  * returns a pointer to the property on success and NULL on failure
  */
 const void *qemu_fdt_getprop(void *fdt, const char *node_path,
                              const char *property, int *lenp,
-                             Error **errp);
+                             bool inherit, Error **errp);
 /**
- * qemu_fdt_getprop_cell: retrieve the value of a given 4 byte property
- * @fdt: pointer to the device tree blob
- * @node_path: node path
- * @property: name of the property to find
- * @lenp: fdt error if any or -EINVAL if the property size is different from
- *        4 bytes, or 4 (expected length of the property) upon success.
- * @errp: handle to an error object
- *
- * returns the property value on success
- */
+* qemu_fdt_getprop_cell: retrieve the value of a given 4 byte property
+* @fdt: pointer to the device tree blob
+* @node_path: node path
+* @property: name of the property to find
+* @ofset: the index of 32bit cell to retrive
+* @inherit: if not found in node, look for property in parent
+* @errp: handle to an error object
+*
+* returns the property value on success
+*/
 uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
-                               const char *property, int *lenp,
-                               Error **errp);
+                               const char *property, int offset,
+                               bool inherit, Error **errp);
 uint32_t qemu_fdt_get_phandle(void *fdt, const char *path);
 uint32_t qemu_fdt_alloc_phandle(void *fdt);
 int qemu_fdt_nop_node(void *fdt, const char *node_path);
@@ -193,6 +194,11 @@ int qemu_fdt_setprop_sized_cells_from_array(void *fdt,
     })
 
 
+int qemu_devtree_getparent(void *fdt, char *node_path,
+                           const char *current);
+
+#define DT_PATH_LENGTH 1024
+
 /**
  * qemu_fdt_randomize_seeds:
  * @fdt: device tree blob
diff --git a/system/device_tree.c b/system/device_tree.c
index 1ea1962984..41bde0ba5a 100644
--- a/system/device_tree.c
+++ b/system/device_tree.c
@@ -429,7 +429,8 @@ int qemu_fdt_setprop_string_array(void *fdt, const char *node_path,
 }
 
 const void *qemu_fdt_getprop(void *fdt, const char *node_path,
-                             const char *property, int *lenp, Error **errp)
+                             const char *property, int *lenp,
+                             bool inherit, Error **errp)
 {
     int len;
     const void *r;
@@ -439,31 +440,35 @@ const void *qemu_fdt_getprop(void *fdt, const char *node_path,
     }
     r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp);
     if (!r) {
+        char parent[DT_PATH_LENGTH];
+        if (inherit && !qemu_devtree_getparent(fdt, parent, node_path)) {
+            return qemu_fdt_getprop(fdt, parent, property, lenp, true, errp);
+        }
         error_setg(errp, "%s: Couldn't get %s/%s: %s", __func__,
                   node_path, property, fdt_strerror(*lenp));
+        return NULL;
     }
     return r;
 }
 
 uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
-                               const char *property, int *lenp, Error **errp)
+                               const char *property, int offset,
+                               bool inherit, Error **errp)
 {
     int len;
     const uint32_t *p;
 
-    if (!lenp) {
-        lenp = &len;
-    }
-    p = qemu_fdt_getprop(fdt, node_path, property, lenp, errp);
+    p = qemu_fdt_getprop(fdt, node_path, property, &len,
+                                         inherit, errp);
     if (!p) {
         return 0;
-    } else if (*lenp != 4) {
+    }
+    if (len < (offset + 1) * 4) {
         error_setg(errp, "%s: %s/%s not 4 bytes long (not a cell?)",
                    __func__, node_path, property);
-        *lenp = -EINVAL;
         return 0;
     }
-    return be32_to_cpu(*p);
+    return be32_to_cpu(p[offset]);
 }
 
 uint32_t qemu_fdt_get_phandle(void *fdt, const char *path)
@@ -633,6 +638,16 @@ out:
     return ret;
 }
 
+int qemu_devtree_getparent(void *fdt, char *node_path, const char *current)
+{
+    int offset = fdt_path_offset(fdt, current);
+    int parent_offset = fdt_supernode_atdepth_offset(fdt, offset,
+        fdt_node_depth(fdt, offset) - 1, NULL);
+
+    return parent_offset >= 0 ?
+        fdt_get_path(fdt, parent_offset, node_path, DT_PATH_LENGTH) : 1;
+}
+
 void qmp_dumpdtb(const char *filename, Error **errp)
 {
     ERRP_GUARD();
-- 
2.43.0