[PATCH 2/2] ubi: open volumes define in device tree

[Hauke Mehrtens]

This makes it possible to define a volume to open in device tree. This
is helpful when a root file system is on a ubi layer. Without this
patch it is only possible to device with with kernel command line
parameters.

Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 Documentation/devicetree/bindings/mtd/ubi.txt | 22 +++++++++++++++++
 drivers/mtd/ubi/build.c                       | 34 +++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/Documentation/devicetree/bindings/mtd/ubi.txt b/Documentation/devicetree/bindings/mtd/ubi.txt
index 5fcd47e..f87a7d8 100644
--- a/Documentation/devicetree/bindings/mtd/ubi.txt
+++ b/Documentation/devicetree/bindings/mtd/ubi.txt
@@ -13,6 +13,16 @@ Describe of a UBI layer in device tree.
  			which have to be assigned to the newly created UBI
  			device (assigned automatically by default)
 
+Partitions on a UBI layer can be defined:
+
+ - compatible: 		"ubi,volume"
+ - name:		name of the ubi volume to open
+ - ubi-mode:		mode of the ubi volume to open value:
+ 			UBI_READONLY:	1
+ 			UBI_READWRITE:	2
+ 			UBI_EXCLUSIVE:	3
+ 			UBI_METAONLY:	4
+
 Example:
 
 partitions {
@@ -29,5 +39,17 @@ partitions {
 		label = "system_sw";
 		reg = <0x1c0000 0xc800000>;
 		compatible = "ubi,device";
+
+		rootfsA at 0 {
+			compatible = "ubi,volume";
+			name = "rootfsA";
+			ubi-mode = <1>;
+		};
+
+		data_vol at 0 {
+			compatible = "ubi,volume";
+			name = "data_vol";
+			ubi-mode = <2>;
+		};
 	};
 };
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 16baeb5..1c22533 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -1,6 +1,7 @@
 /*
  * Copyright (c) International Business Machines Corp., 2006
  * Copyright (c) Nokia Corporation, 2007
+ * Copyright (c) 2016 Hauke Mehrtens <hauke at hauke-m.de>
  *
  * 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
@@ -33,6 +34,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/stringify.h>
+#include <linux/of.h>
 #include <linux/namei.h>
 #include <linux/stat.h>
 #include <linux/miscdevice.h>
@@ -43,6 +45,7 @@
 #include <linux/slab.h>
 #include <linux/major.h>
 #include "ubi.h"
+#include "../mtdcore.h"
 
 /* Maximum length of the 'mtd=' parameter */
 #define MTD_PARAM_LEN_MAX 64
@@ -1205,6 +1208,7 @@ static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
 static int __init ubi_init(void)
 {
 	int err, i, k;
+	struct mtd_info *mtd_it;
 
 	/* Ensure that EC and VID headers have correct size */
 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
@@ -1285,6 +1289,36 @@ static int __init ubi_init(void)
 		}
 	}
 
+	mtd_for_each_device(mtd_it) {
+		struct mtd_info *mtd;
+		u32 ubi_num = 0;
+		u32 vid_hdr_offs = 0;
+		u32 max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
+
+		mtd = get_mtd_device(mtd_it, -1);
+
+		if (!of_device_is_compatible(mtd->dev.of_node, "ubi,device")) {
+			put_mtd_device(mtd);
+			continue;
+		}
+
+		of_property_read_u32(mtd->dev.of_node, "vid_hdr_offs",
+				     &vid_hdr_offs);
+		of_property_read_u32(mtd->dev.of_node, "max_beb_per1024",
+				     &max_beb_per1024);
+		of_property_read_u32(mtd->dev.of_node, "ubi_num", &ubi_num);
+
+		mutex_lock(&ubi_devices_mutex);
+		err = ubi_attach_mtd_dev(mtd, ubi_num, vid_hdr_offs,
+					 max_beb_per1024);
+		mutex_unlock(&ubi_devices_mutex);
+		if (err < 0) {
+			pr_err("UBI error: cannot attach mtd%d",
+			       mtd->index);
+		}
+		put_mtd_device(mtd);
+	}
+
 	err = ubiblock_init();
 	if (err) {
 		pr_err("UBI error: block: cannot initialize, error %d", err);
-- 
2.8.1