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-rw-r--r--libfdt/fdt_overlay.c251
1 files changed, 218 insertions, 33 deletions
diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c
index 56cb70ed4445..bd81241e6658 100644
--- a/libfdt/fdt_overlay.c
+++ b/libfdt/fdt_overlay.c
@@ -21,14 +21,14 @@
*/
static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
{
- const uint32_t *val;
+ const fdt32_t *val;
int len;
val = fdt_getprop(fdto, fragment, "target", &len);
if (!val)
return 0;
- if ((len != sizeof(*val)) || (*val == (uint32_t)-1))
+ if ((len != sizeof(*val)) || (fdt32_to_cpu(*val) == (uint32_t)-1))
return (uint32_t)-1;
return fdt32_to_cpu(*val);
@@ -39,6 +39,7 @@ static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
* @fdt: Base device tree blob
* @fdto: Device tree overlay blob
* @fragment: node offset of the fragment in the overlay
+ * @pathp: pointer which receives the path of the target (or NULL)
*
* overlay_get_target() retrieves the target offset in the base
* device tree of a fragment, no matter how the actual targetting is
@@ -49,37 +50,47 @@ static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
* Negative error code on error
*/
static int overlay_get_target(const void *fdt, const void *fdto,
- int fragment)
+ int fragment, char const **pathp)
{
uint32_t phandle;
- const char *path;
- int path_len;
+ const char *path = NULL;
+ int path_len = 0, ret;
/* Try first to do a phandle based lookup */
phandle = overlay_get_target_phandle(fdto, fragment);
if (phandle == (uint32_t)-1)
return -FDT_ERR_BADPHANDLE;
- if (phandle)
- return fdt_node_offset_by_phandle(fdt, phandle);
+ /* no phandle, try path */
+ if (!phandle) {
+ /* And then a path based lookup */
+ path = fdt_getprop(fdto, fragment, "target-path", &path_len);
+ if (path)
+ ret = fdt_path_offset(fdt, path);
+ else
+ ret = path_len;
+ } else
+ ret = fdt_node_offset_by_phandle(fdt, phandle);
- /* And then a path based lookup */
- path = fdt_getprop(fdto, fragment, "target-path", &path_len);
- if (!path) {
- /*
- * If we haven't found either a target or a
- * target-path property in a node that contains a
- * __overlay__ subnode (we wouldn't be called
- * otherwise), consider it a improperly written
- * overlay
- */
- if (path_len == -FDT_ERR_NOTFOUND)
- return -FDT_ERR_BADOVERLAY;
+ /*
+ * If we haven't found either a target or a
+ * target-path property in a node that contains a
+ * __overlay__ subnode (we wouldn't be called
+ * otherwise), consider it a improperly written
+ * overlay
+ */
+ if (ret < 0 && path_len == -FDT_ERR_NOTFOUND)
+ ret = -FDT_ERR_BADOVERLAY;
+
+ /* return on error */
+ if (ret < 0)
+ return ret;
- return path_len;
- }
+ /* return pointer to path (if available) */
+ if (pathp)
+ *pathp = path ? path : NULL;
- return fdt_path_offset(fdt, path);
+ return ret;
}
/**
@@ -99,7 +110,7 @@ static int overlay_get_target(const void *fdt, const void *fdto,
static int overlay_phandle_add_offset(void *fdt, int node,
const char *name, uint32_t delta)
{
- const uint32_t *val;
+ const fdt32_t *val;
uint32_t adj_val;
int len;
@@ -210,7 +221,7 @@ static int overlay_update_local_node_references(void *fdto,
int ret;
fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
- const uint32_t *fixup_val;
+ const fdt32_t *fixup_val;
const char *tree_val;
const char *name;
int fixup_len;
@@ -234,7 +245,8 @@ static int overlay_update_local_node_references(void *fdto,
}
for (i = 0; i < (fixup_len / sizeof(uint32_t)); i++) {
- uint32_t adj_val, poffset;
+ fdt32_t adj_val;
+ uint32_t poffset;
poffset = fdt32_to_cpu(fixup_val[i]);
@@ -246,9 +258,7 @@ static int overlay_update_local_node_references(void *fdto,
*/
memcpy(&adj_val, tree_val + poffset, sizeof(adj_val));
- adj_val = fdt32_to_cpu(adj_val);
- adj_val += delta;
- adj_val = cpu_to_fdt32(adj_val);
+ adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta);
ret = fdt_setprop_inplace_namelen_partial(fdto,
tree_node,
@@ -272,7 +282,7 @@ static int overlay_update_local_node_references(void *fdto,
tree_child = fdt_subnode_offset(fdto, tree_node,
fixup_child_name);
- if (ret == -FDT_ERR_NOTFOUND)
+ if (tree_child == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
if (tree_child < 0)
return tree_child;
@@ -356,6 +366,7 @@ static int overlay_fixup_one_phandle(void *fdt, void *fdto,
{
const char *symbol_path;
uint32_t phandle;
+ fdt32_t phandle_prop;
int symbol_off, fixup_off;
int prop_len;
@@ -381,10 +392,11 @@ static int overlay_fixup_one_phandle(void *fdt, void *fdto,
if (fixup_off < 0)
return fixup_off;
- phandle = cpu_to_fdt32(phandle);
+ phandle_prop = cpu_to_fdt32(phandle);
return fdt_setprop_inplace_namelen_partial(fdto, fixup_off,
name, name_len, poffset,
- &phandle, sizeof(phandle));
+ &phandle_prop,
+ sizeof(phandle_prop));
};
/**
@@ -589,7 +601,7 @@ static int overlay_apply_node(void *fdt, int target,
*
* overlay_merge() merges an overlay into its base device tree.
*
- * This is the final step in the device tree overlay application
+ * This is the next to last step in the device tree overlay application
* process, when all the phandles have been adjusted and resolved and
* you just have to merge overlay into the base device tree.
*
@@ -617,7 +629,7 @@ static int overlay_merge(void *fdt, void *fdto)
if (overlay < 0)
return overlay;
- target = overlay_get_target(fdt, fdto, fragment);
+ target = overlay_get_target(fdt, fdto, fragment, NULL);
if (target < 0)
return target;
@@ -629,6 +641,175 @@ static int overlay_merge(void *fdt, void *fdto)
return 0;
}
+static int get_path_len(const void *fdt, int nodeoffset)
+{
+ int len = 0, namelen;
+ const char *name;
+
+ FDT_CHECK_HEADER(fdt);
+
+ for (;;) {
+ name = fdt_get_name(fdt, nodeoffset, &namelen);
+ if (!name)
+ return namelen;
+
+ /* root? we're done */
+ if (namelen == 0)
+ break;
+
+ nodeoffset = fdt_parent_offset(fdt, nodeoffset);
+ if (nodeoffset < 0)
+ return nodeoffset;
+ len += namelen + 1;
+ }
+
+ /* in case of root pretend it's "/" */
+ if (len == 0)
+ len++;
+ return len;
+}
+
+/**
+ * overlay_symbol_update - Update the symbols of base tree after a merge
+ * @fdt: Base Device Tree blob
+ * @fdto: Device tree overlay blob
+ *
+ * overlay_symbol_update() updates the symbols of the base tree with the
+ * symbols of the applied overlay
+ *
+ * This is the last step in the device tree overlay application
+ * process, allowing the reference of overlay symbols by subsequent
+ * overlay operations.
+ *
+ * returns:
+ * 0 on success
+ * Negative error code on failure
+ */
+static int overlay_symbol_update(void *fdt, void *fdto)
+{
+ int root_sym, ov_sym, prop, path_len, fragment, target;
+ int len, frag_name_len, ret, rel_path_len;
+ const char *s, *e;
+ const char *path;
+ const char *name;
+ const char *frag_name;
+ const char *rel_path;
+ const char *target_path;
+ char *buf;
+ void *p;
+
+ ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__");
+
+ /* if no overlay symbols exist no problem */
+ if (ov_sym < 0)
+ return 0;
+
+ root_sym = fdt_subnode_offset(fdt, 0, "__symbols__");
+
+ /* it no root symbols exist we should create them */
+ if (root_sym == -FDT_ERR_NOTFOUND)
+ root_sym = fdt_add_subnode(fdt, 0, "__symbols__");
+
+ /* any error is fatal now */
+ if (root_sym < 0)
+ return root_sym;
+
+ /* iterate over each overlay symbol */
+ fdt_for_each_property_offset(prop, fdto, ov_sym) {
+ path = fdt_getprop_by_offset(fdto, prop, &name, &path_len);
+ if (!path)
+ return path_len;
+
+ /* verify it's a string property (terminated by a single \0) */
+ if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1])
+ return -FDT_ERR_BADVALUE;
+
+ /* keep end marker to avoid strlen() */
+ e = path + path_len;
+
+ /* format: /<fragment-name>/__overlay__/<relative-subnode-path> */
+
+ if (*path != '/')
+ return -FDT_ERR_BADVALUE;
+
+ /* get fragment name first */
+ s = strchr(path + 1, '/');
+ if (!s)
+ return -FDT_ERR_BADOVERLAY;
+
+ frag_name = path + 1;
+ frag_name_len = s - path - 1;
+
+ /* verify format; safe since "s" lies in \0 terminated prop */
+ len = sizeof("/__overlay__/") - 1;
+ if ((e - s) < len || memcmp(s, "/__overlay__/", len))
+ return -FDT_ERR_BADOVERLAY;
+
+ rel_path = s + len;
+ rel_path_len = e - rel_path;
+
+ /* find the fragment index in which the symbol lies */
+ ret = fdt_subnode_offset_namelen(fdto, 0, frag_name,
+ frag_name_len);
+ /* not found? */
+ if (ret < 0)
+ return -FDT_ERR_BADOVERLAY;
+ fragment = ret;
+
+ /* an __overlay__ subnode must exist */
+ ret = fdt_subnode_offset(fdto, fragment, "__overlay__");
+ if (ret < 0)
+ return -FDT_ERR_BADOVERLAY;
+
+ /* get the target of the fragment */
+ ret = overlay_get_target(fdt, fdto, fragment, &target_path);
+ if (ret < 0)
+ return ret;
+ target = ret;
+
+ /* if we have a target path use */
+ if (!target_path) {
+ ret = get_path_len(fdt, target);
+ if (ret < 0)
+ return ret;
+ len = ret;
+ } else {
+ len = strlen(target_path);
+ }
+
+ ret = fdt_setprop_placeholder(fdt, root_sym, name,
+ len + (len > 1) + rel_path_len + 1, &p);
+ if (ret < 0)
+ return ret;
+
+ if (!target_path) {
+ /* again in case setprop_placeholder changed it */
+ ret = overlay_get_target(fdt, fdto, fragment, &target_path);
+ if (ret < 0)
+ return ret;
+ target = ret;
+ }
+
+ buf = p;
+ if (len > 1) { /* target is not root */
+ if (!target_path) {
+ ret = fdt_get_path(fdt, target, buf, len + 1);
+ if (ret < 0)
+ return ret;
+ } else
+ memcpy(buf, target_path, len + 1);
+
+ } else
+ len--;
+
+ buf[len] = '/';
+ memcpy(buf + len + 1, rel_path, rel_path_len);
+ buf[len + 1 + rel_path_len] = '\0';
+ }
+
+ return 0;
+}
+
int fdt_overlay_apply(void *fdt, void *fdto)
{
uint32_t delta = fdt_get_max_phandle(fdt);
@@ -653,6 +834,10 @@ int fdt_overlay_apply(void *fdt, void *fdto)
if (ret)
goto err;
+ ret = overlay_symbol_update(fdt, fdto);
+ if (ret)
+ goto err;
+
/*
* The overlay has been damaged, erase its magic.
*/