mtd: parsers: ofpart: support Linksys Northstar partitions

This allows extending ofpart parser with support for Linksys Northstar
devices. That support uses recently added quirks mechanism.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210312134919.7767-2-zajec5@gmail.com

drivers/mtd/parsers/Kconfig

@@ -76,6 +76,16 @@ config MTD_OF_PARTS_BCM4908
 	  that can have multiple "firmware" partitions. It takes care of
 	  finding currently used one and backup ones.
 
+config MTD_OF_PARTS_LINKSYS_NS
+	bool "Linksys Northstar partitioning support"
+	depends on MTD_OF_PARTS && (ARCH_BCM_5301X || ARCH_BCM4908 || COMPILE_TEST)
+	default ARCH_BCM_5301X
+	help
+	  This provides partitions parser for Linksys devices based on Broadcom
+	  Northstar architecture. Linksys commonly uses fixed flash layout with
+	  two "firmware" partitions. Currently used firmware has to be detected
+	  using CFE environment variable.
+
 config MTD_PARSER_IMAGETAG
 	tristate "Parser for BCM963XX Image Tag format partitions"
 	depends on BCM63XX || BMIPS_GENERIC || COMPILE_TEST

drivers/mtd/parsers/Makefile

@@ -6,6 +6,7 @@ obj-$(CONFIG_MTD_CMDLINE_PARTS)		+= cmdlinepart.o
 obj-$(CONFIG_MTD_OF_PARTS)		+= ofpart.o
 ofpart-y				+= ofpart_core.o
 ofpart-$(CONFIG_MTD_OF_PARTS_BCM4908)	+= ofpart_bcm4908.o
+ofpart-$(CONFIG_MTD_OF_PARTS_LINKSYS_NS)+= ofpart_linksys_ns.o
 obj-$(CONFIG_MTD_PARSER_IMAGETAG)	+= parser_imagetag.o
 obj-$(CONFIG_MTD_AFS_PARTS)		+= afs.o
 obj-$(CONFIG_MTD_PARSER_TRX)		+= parser_trx.o

drivers/mtd/parsers/ofpart_core.c

@@ -17,6 +17,7 @@
 #include <linux/mtd/partitions.h>
 
 #include "ofpart_bcm4908.h"
+#include "ofpart_linksys_ns.h"
 
 struct fixed_partitions_quirks {
 	int (*post_parse)(struct mtd_info *mtd, struct mtd_partition *parts, int nr_parts);
@@ -26,6 +27,10 @@ static struct fixed_partitions_quirks bcm4908_partitions_quirks = {
 	.post_parse = bcm4908_partitions_post_parse,
 };
 
+static struct fixed_partitions_quirks linksys_ns_partitions_quirks = {
+	.post_parse = linksys_ns_partitions_post_parse,
+};
+
 static const struct of_device_id parse_ofpart_match_table[];
 
 static bool node_has_compatible(struct device_node *pp)
@@ -167,6 +172,7 @@ static const struct of_device_id parse_ofpart_match_table[] = {
 	{ .compatible = "fixed-partitions" },
 	/* Customized */
 	{ .compatible = "brcm,bcm4908-partitions", .data = &bcm4908_partitions_quirks, },
+	{ .compatible = "linksys,ns-partitions", .data = &linksys_ns_partitions_quirks, },
 	{},
 };
 MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);

drivers/mtd/parsers/ofpart_linksys_ns.c

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
+ */
+
+#include <linux/bcm47xx_nvram.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+#include "ofpart_linksys_ns.h"
+
+#define NVRAM_BOOT_PART		"bootpartition"
+
+static int ofpart_linksys_ns_bootpartition(void)
+{
+	char buf[4];
+	int bootpartition;
+
+	/* Check CFE environment variable */
+	if (bcm47xx_nvram_getenv(NVRAM_BOOT_PART, buf, sizeof(buf)) > 0) {
+		if (!kstrtoint(buf, 0, &bootpartition))
+			return bootpartition;
+		pr_warn("Failed to parse %s value \"%s\"\n", NVRAM_BOOT_PART,
+			buf);
+	} else {
+		pr_warn("Failed to get NVRAM \"%s\"\n", NVRAM_BOOT_PART);
+	}
+
+	return 0;
+}
+
+int linksys_ns_partitions_post_parse(struct mtd_info *mtd,
+				     struct mtd_partition *parts,
+				     int nr_parts)
+{
+	int bootpartition = ofpart_linksys_ns_bootpartition();
+	int trx_idx = 0;
+	int i;
+
+	for (i = 0; i < nr_parts; i++) {
+		if (of_device_is_compatible(parts[i].of_node, "linksys,ns-firmware")) {
+			if (trx_idx++ == bootpartition)
+				parts[i].name = "firmware";
+			else
+				parts[i].name = "backup";
+		}
+	}
+
+	return 0;
+}

drivers/mtd/parsers/ofpart_linksys_ns.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __OFPART_LINKSYS_NS_H
+#define __OFPART_LINKSYS_NS_H
+
+#ifdef CONFIG_MTD_OF_PARTS_LINKSYS_NS
+int linksys_ns_partitions_post_parse(struct mtd_info *mtd,
+				     struct mtd_partition *parts,
+				     int nr_parts);
+#else
+static inline int linksys_ns_partitions_post_parse(struct mtd_info *mtd,
+						   struct mtd_partition *parts,
+						   int nr_parts)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+#endif