[PATCH] dm: core: support reading a single indexed u64 value

[Ashok Reddy Soma]

Add helper function to allow reading a single indexed u64 value from a
device-tree property containing multiple u64 values, that is an array of
u64's.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma at amd.com>
---

 drivers/core/of_access.c | 22 ++++++++++++++++++++++
 drivers/core/ofnode.c    | 30 ++++++++++++++++++++++++++++++
 include/dm/of_access.h   | 19 +++++++++++++++++++
 include/dm/ofnode.h      | 12 ++++++++++++
 4 files changed, 83 insertions(+)

diff --git a/drivers/core/of_access.c b/drivers/core/of_access.c
index 57f10445b1..b5c315ac3a 100644
--- a/drivers/core/of_access.c
+++ b/drivers/core/of_access.c
@@ -570,6 +570,28 @@ int of_read_u32_index(const struct device_node *np, const char *propname,
 	return 0;
 }
 
+int of_read_u64_index(const struct device_node *np, const char *propname,
+		      int index, u64 *outp)
+{
+	const __be64 *val;
+
+	debug("%s: %s: ", __func__, propname);
+	if (!np)
+		return -EINVAL;
+
+	val = of_find_property_value_of_size(np, propname,
+					     sizeof(*outp) * (index + 1));
+	if (IS_ERR(val)) {
+		debug("(not found)\n");
+		return PTR_ERR(val);
+	}
+
+	*outp = be64_to_cpup(val + index);
+	debug("%#x (%d)\n", *outp, *outp);
+
+	return 0;
+}
+
 int of_read_u64(const struct device_node *np, const char *propname, u64 *outp)
 {
 	const __be64 *val;
diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
index 8df16e56af..9a43343ed3 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -344,6 +344,36 @@ int ofnode_read_u32_index(ofnode node, const char *propname, int index,
 	return 0;
 }
 
+int ofnode_read_u64_index(ofnode node, const char *propname, int index,
+			  u64 *outp)
+{
+	const fdt64_t *cell;
+	int len;
+
+	assert(ofnode_valid(node));
+
+	if (ofnode_is_np(node))
+		return of_read_u64_index(ofnode_to_np(node), propname, index,
+					 outp);
+
+	cell = fdt_getprop(ofnode_to_fdt(node), ofnode_to_offset(node),
+			   propname, &len);
+	if (!cell) {
+		debug("(not found)\n");
+		return -EINVAL;
+	}
+
+	if (len < (sizeof(int) * (index + 1))) {
+		debug("(not large enough)\n");
+		return -EOVERFLOW;
+	}
+
+	*outp = fdt64_to_cpu(cell[index]);
+	debug("%#llx (%lld)\n", *outp, *outp);
+
+	return 0;
+}
+
 u32 ofnode_read_u32_index_default(ofnode node, const char *propname, int index,
 				  u32 def)
 {
diff --git a/include/dm/of_access.h b/include/dm/of_access.h
index c556a18f7d..9e027c9293 100644
--- a/include/dm/of_access.h
+++ b/include/dm/of_access.h
@@ -333,6 +333,25 @@ int of_read_u32(const struct device_node *np, const char *propname, u32 *outp);
 int of_read_u32_index(const struct device_node *np, const char *propname,
 		      int index, u32 *outp);
 
+/**
+ * of_read_u64_index() - Find and read a 64-bit value from a multi-value
+ *                       property
+ *
+ * Search for a property in a device node and read a 64-bit value from
+ * it.
+ *
+ * @np:		device node from which the property value is to be read.
+ * @propname:	name of the property to be searched.
+ * @index:	index of the u32 in the list of values
+ * @outp:	pointer to return value, modified only if return value is 0.
+ *
+ * Return:
+ *   0 on success, -EINVAL if the property does not exist, or -EOVERFLOW if the
+ *   property data isn't large enough.
+ */
+int of_read_u64_index(const struct device_node *np, const char *propname,
+		      int index, u64 *outp);
+
 /**
  * of_read_u64() - Find and read a 64-bit integer from a property
  *
diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index 0f38b3e736..0a85db31f3 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -434,6 +434,18 @@ int ofnode_read_u32(ofnode node, const char *propname, u32 *outp);
 int ofnode_read_u32_index(ofnode node, const char *propname, int index,
 			  u32 *outp);
 
+/**
+ * ofnode_read_u64_index() - Read a 64-bit integer from a multi-value property
+ *
+ * @node:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @outp:	place to put value (if found)
+ * Return: 0 if OK, -ve on error
+ */
+int ofnode_read_u64_index(ofnode node, const char *propname, int index,
+			  u64 *outp);
+
 /**
  * ofnode_read_s32() - Read a 32-bit integer from a property
  *
-- 
2.17.1