Thread (1 message) 1 message, 1 author, 2016-07-12

Re: [PATCH v2 5/6] libfdt: Add fdt_setprop_inplace_namelen_partial

From: David Gibson <hidden>
Date: 2016-07-12 11:45:20

On Mon, Jul 11, 2016 at 09:56:22PM +0200, Maxime Ripard wrote:
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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
Acked-by: Simon Glass <redacted>
Reviewed-by: David Gibson <redacted>

Now it just needs some testcases..
quoted hunk
---
 libfdt/fdt_wip.c | 29 +++++++++++++++++++++++++----
 libfdt/libfdt.h  | 21 +++++++++++++++++++++
 2 files changed, 46 insertions(+), 4 deletions(-)
diff --git a/libfdt/fdt_wip.c b/libfdt/fdt_wip.c
index c5bbb68d3273..fd53e0b67416 100644
--- a/libfdt/fdt_wip.c
+++ b/libfdt/fdt_wip.c
@@ -55,21 +55,42 @@
 
 #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((unsigned char *)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)
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 1da2c540b607..a22a16b6878a 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -1072,6 +1072,27 @@ 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
-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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