[RFC v5 2/4] pstore/blk: add sample for pstore_blk

[liaoweixiong <liaoweixiong@allwinnertech.com>]

It is a sample for pstore_blk, using general ram rather than block device.
According to pstore_blk, the data will be saved to ram buffer if not
register device path and apis for panic. So, it can only used to dump
Oops and some things will not reboot.

Signed-off-by: liaoweixiong <liaoweixiong@allwinnertech.com>
---
 fs/pstore/Kconfig  |  9 +++++++++
 fs/pstore/Makefile |  2 ++
 fs/pstore/blkbuf.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 fs/pstore/blkbuf.c

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index a881c53..18b1fe6 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -159,3 +159,12 @@ config PSTORE_BLK
 	help
 	  This enables panic and oops message to be logged to a block dev
 	  where it can be read back at some later point.
+
+config PSTORE_BLKBUF
+	tristate "pstore block buffer sample"
+	depends on PSTORE_BLK
+	help
+	  This is a sample for pstore block, but do NOT have a block dev.
+	  According to pstore_blk, the data will be saved to ram buffer and
+	  dropped when reboot. So, it can only used to dump Oops and some
+	  things will not reboot.
diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
index c431700..4a6cde1 100644
--- a/fs/pstore/Makefile
+++ b/fs/pstore/Makefile
@@ -15,3 +15,5 @@ obj-$(CONFIG_PSTORE_RAM)	+= ramoops.o
 
 obj-$(CONFIG_PSTORE_BLK)	+= pstore_blk.o
 pstore_blk-y += blkzone.o
+
+obj-$(CONFIG_PSTORE_BLKBUF)	+= blkbuf.o
diff --git a/fs/pstore/blkbuf.c b/fs/pstore/blkbuf.c
new file mode 100644
index 0000000..f1c6f57
--- /dev/null
+++ b/fs/pstore/blkbuf.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * blkbuf.c: Block device Oops/Panic logger
+ *
+ * Copyright (C) 2019 liaoweixiong <liaoweixiong@gallwinnertech.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#define pr_fmt(fmt) "blkbuf: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pstore_blk.h>
+
+struct blkz_info blkbuf_info = {
+	.owner = THIS_MODULE,
+	.name = "blkbuf",
+	.part_size = 512 * 1024,
+	.dmesg_size = 64 * 1024,
+	.dump_oops = true,
+};
+
+static int __init blkbuf_init(void)
+{
+	return blkz_register(&blkbuf_info);
+}
+module_init(blkbuf_init);
+
+static void __exit blkbuf_exit(void)
+{
+	blkz_unregister(&blkbuf_info);
+}
+module_exit(blkbuf_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("liaoweixiong <liaoweixiong@allwinnertech.com>");
+MODULE_DESCRIPTION("Sample for Pstore BLK with Oops logger");
-- 
1.9.1