File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/mtd/ofpart.c b/drivers/mtd/ofpart.c
new file mode 100644
index 0000000..9ed6038
--- /dev/null
+++ b/drivers/mtd/ofpart.c
@@ -0,0 +1,235 @@
+/*
+ * Flash partitions described by the OF (or flattened) device tree
+ *
+ * Copyright © 2006 MontaVista Software Inc.
+ * Author: Vitaly Wool <vwool@ru.mvista.com>
+ *
+ * Revised to handle newer style flash binding by:
+ *   Copyright © 2007 David Gibson, IBM Corporation.
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/mtd/mtd.h>
+#include <linux/slab.h>
+#include <linux/mtd/partitions.h>
+
+static bool node_has_compatible(struct device_node *pp)
+{
+	return of_get_property(pp, "compatible", NULL);
+}
+
+static int parse_ofpart_partitions(struct mtd_info *master,
+				   struct mtd_partition **pparts,
+				   struct mtd_part_parser_data *data)
+{
+	struct device_node *mtd_node;
+	struct device_node *ofpart_node;
+	const char *partname;
+	struct device_node *pp;
+	int nr_parts, i, ret = 0;
+	bool dedicated = true;
+
+
+	if (!data)
+		return 0;
+
+	mtd_node = data->of_node;
+	if (!mtd_node)
+		return 0;
+
+	ofpart_node = of_get_child_by_name(mtd_node, "partitions");
+	if (!ofpart_node) {
+		/*
+		 * We might get here even when ofpart isn't used at all (e.g.,
+		 * when using another parser), so don't be louder than
+		 * KERN_DEBUG
+		 */
+		pr_debug("%s: 'partitions' subnode not found on %s. Trying to parse direct subnodes as partitions.\n",
+			 master->name, mtd_node->full_name);
+		ofpart_node = mtd_node;
+		dedicated = false;
+	} else if (!of_device_is_compatible(ofpart_node, "fixed-partitions")) {
+		/* The 'partitions' subnode might be used by another parser */
+		return 0;
+	}
+
+	/* First count the subnodes */
+	nr_parts = 0;
+	for_each_child_of_node(ofpart_node,  pp) {
+		if (!dedicated && node_has_compatible(pp))
+			continue;
+
+		nr_parts++;
+	}
+
+	if (nr_parts == 0)
+		return 0;
+
+	*pparts = kzalloc(nr_parts * sizeof(**pparts), GFP_KERNEL);
+	if (!*pparts)
+		return -ENOMEM;
+
+	i = 0;
+	for_each_child_of_node(ofpart_node,  pp) {
+		const __be32 *reg;
+		int len;
+		int a_cells, s_cells;
+
+		if (!dedicated && node_has_compatible(pp))
+			continue;
+
+		reg = of_get_property(pp, "reg", &len);
+		if (!reg) {
+			if (dedicated) {
+				pr_debug("%s: ofpart partition %s (%s) missing reg property.\n",
+					 master->name, pp->full_name,
+					 mtd_node->full_name);
+				goto ofpart_fail;
+			} else {
+				nr_parts--;
+				continue;
+			}
+		}
+
+		a_cells = of_n_addr_cells(pp);
+		s_cells = of_n_size_cells(pp);
+		if (len / 4 != a_cells + s_cells) {
+			pr_debug("%s: ofpart partition %s (%s) error parsing reg property.\n",
+				 master->name, pp->full_name,
+				 mtd_node->full_name);
+			goto ofpart_fail;
+		}
+
+		(*pparts)[i].offset = of_read_number(reg, a_cells);
+		(*pparts)[i].size = of_read_number(reg + a_cells, s_cells);
+
+		partname = of_get_property(pp, "label", &len);
+		if (!partname)
+			partname = of_get_property(pp, "name", &len);
+		(*pparts)[i].name = partname;
+
+		if (of_get_property(pp, "read-only", &len))
+			(*pparts)[i].mask_flags |= MTD_WRITEABLE;
+
+		if (of_get_property(pp, "lock", &len))
+			(*pparts)[i].mask_flags |= MTD_POWERUP_LOCK;
+
+		i++;
+	}
+
+	if (!nr_parts)
+		goto ofpart_none;
+
+	return nr_parts;
+
+ofpart_fail:
+	pr_err("%s: error parsing ofpart partition %s (%s)\n",
+	       master->name, pp->full_name, mtd_node->full_name);
+	ret = -EINVAL;
+ofpart_none:
+	of_node_put(pp);
+	kfree(*pparts);
+	*pparts = NULL;
+	return ret;
+}
+
+static struct mtd_part_parser ofpart_parser = {
+	.owner = THIS_MODULE,
+	.parse_fn = parse_ofpart_partitions,
+	.name = "ofpart",
+};
+
+static int parse_ofoldpart_partitions(struct mtd_info *master,
+				      struct mtd_partition **pparts,
+				      struct mtd_part_parser_data *data)
+{
+	struct device_node *dp;
+	int i, plen, nr_parts;
+	const struct {
+		__be32 offset, len;
+	} *part;
+	const char *names;
+
+	if (!data)
+		return 0;
+
+	dp = data->of_node;
+	if (!dp)
+		return 0;
+
+	part = of_get_property(dp, "partitions", &plen);
+	if (!part)
+		return 0; /* No partitions found */
+
+	pr_warning("Device tree uses obsolete partition map binding: %s\n",
+			dp->full_name);
+
+	nr_parts = plen / sizeof(part[0]);
+
+	*pparts = kzalloc(nr_parts * sizeof(*(*pparts)), GFP_KERNEL);
+	if (!*pparts)
+		return -ENOMEM;
+
+	names = of_get_property(dp, "partition-names", &plen);
+
+	for (i = 0; i < nr_parts; i++) {
+		(*pparts)[i].offset = be32_to_cpu(part->offset);
+		(*pparts)[i].size   = be32_to_cpu(part->len) & ~1;
+		/* bit 0 set signifies read only partition */
+		if (be32_to_cpu(part->len) & 1)
+			(*pparts)[i].mask_flags = MTD_WRITEABLE;
+
+		if (names && (plen > 0)) {
+			int len = strlen(names) + 1;
+
+			(*pparts)[i].name = names;
+			plen -= len;
+			names += len;
+		} else {
+			(*pparts)[i].name = "unnamed";
+		}
+
+		part++;
+	}
+
+	return nr_parts;
+}
+
+static struct mtd_part_parser ofoldpart_parser = {
+	.owner = THIS_MODULE,
+	.parse_fn = parse_ofoldpart_partitions,
+	.name = "ofoldpart",
+};
+
+static int __init ofpart_parser_init(void)
+{
+	register_mtd_parser(&ofpart_parser);
+	register_mtd_parser(&ofoldpart_parser);
+	return 0;
+}
+
+static void __exit ofpart_parser_exit(void)
+{
+	deregister_mtd_parser(&ofpart_parser);
+	deregister_mtd_parser(&ofoldpart_parser);
+}
+
+module_init(ofpart_parser_init);
+module_exit(ofpart_parser_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
+MODULE_AUTHOR("Vitaly Wool, David Gibson");
+/*
+ * When MTD core cannot find the requested parser, it tries to load the module
+ * with the same name. Since we provide the ofoldpart parser, we should have
+ * the corresponding alias.
+ */
+MODULE_ALIAS("ofoldpart");