libfdt: Add fdt_setprop_inplace_namelen_partial

Add a function to modify inplace only a portion of a property..

This is especially useful when the property is an array of values, and you
want to update one of them without changing the DT size.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Simon Glass <sjg@chromium.org>

diff --git a/include/libfdt.h b/include/libfdt.h
index a55d2d0d8c7b4a3a60bed17a0bf54c1cd9f751f7..4c56711c7132943b8ff0dcea8f68dd21265a1860 100644 (file)
--- a/include/libfdt.h
+++ b/include/libfdt.h
@@ -1053,6 +1053,27 @@ int fdt_size_cells(const void *fdt, int nodeoffset);
 /* Write-in-place functions                                           */
 /**********************************************************************/
 
+/**
+ * fdt_setprop_inplace_namelen_partial - change a property's value,
+ *                                       but not its size
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node whose property to change
+ * @name: name of the property to change
+ * @namelen: number of characters of name to consider
+ * @index: index of the property to change in the array
+ * @val: pointer to data to replace the property value with
+ * @len: length of the property value
+ *
+ * Identical to fdt_setprop_inplace(), but modifies the given property
+ * starting from the given index, and using only the first characters
+ * of the name. It is useful when you want to manipulate only one value of
+ * an array and you have a string that doesn't end with \0.
+ */
+int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
+                                       const char *name, int namelen,
+                                       uint32_t index, const void *val,
+                                       int len);
+
 /**
  * fdt_setprop_inplace - change a property's value, but not its size
  * @fdt: pointer to the device tree blob

diff --git a/lib/libfdt/fdt_wip.c b/lib/libfdt/fdt_wip.c
index 9fe988655fe342c49a293e7c68d3bcd83d2105b6..216c51287d09e8a48c8d92e056263636f448200e 100644 (file)
--- a/lib/libfdt/fdt_wip.c
+++ b/lib/libfdt/fdt_wip.c
@@ -14,21 +14,42 @@
 
 #include "libfdt_internal.h"
 
+int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
+                                       const char *name, int namelen,
+                                       uint32_t index, const void *val,
+                                       int len)
+{
+       void *propval;
+       int proplen;
+
+       propval = fdt_getprop_namelen_w(fdt, nodeoffset, name, namelen,
+                                       &proplen);
+       if (!propval)
+               return proplen;
+
+       if (proplen < (len + index))
+               return -FDT_ERR_NOSPACE;
+
+       memcpy(propval + index, val, len);
+       return 0;
+}
+
 int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
                        const void *val, int len)
 {
-       void *propval;
+       const void *propval;
        int proplen;
 
-       propval = fdt_getprop_w(fdt, nodeoffset, name, &proplen);
+       propval = fdt_getprop(fdt, nodeoffset, name, &proplen);
        if (!propval)
                return proplen;
 
        if (proplen != len)
                return -FDT_ERR_NOSPACE;
 
-       memcpy(propval, val, len);
-       return 0;
+       return fdt_setprop_inplace_namelen_partial(fdt, nodeoffset, name,
+                                                  strlen(name), 0,
+                                                  val, len);
 }
 
 static void _fdt_nop_region(void *start, int len)