lightnvm: Support for Open-Channel SSDs

Open-channel SSDs are devices that share responsibilities with the host
in order to implement and maintain features that typical SSDs keep
strictly in firmware. These include (i) the Flash Translation Layer
(FTL), (ii) bad block management, and (iii) hardware units such as the
flash controller, the interface controller, and large amounts of flash
chips. In this way, Open-channels SSDs exposes direct access to their
physical flash storage, while keeping a subset of the internal features
of SSDs.

LightNVM is a specification that gives support to Open-channel SSDs
LightNVM allows the host to manage data placement, garbage collection,
and parallelism. Device specific responsibilities such as bad block
management, FTL extensions to support atomic IOs, or metadata
persistence are still handled by the device.

The implementation of LightNVM consists of two parts: core and
(multiple) targets. The core implements functionality shared across
targets. This is initialization, teardown and statistics. The targets
implement the interface that exposes physical flash to user-space
applications. Examples of such targets include key-value store,
object-store, as well as traditional block devices, which can be
application-specific.

Contributions in this patch from:

  Javier Gonzalez <jg@lightnvm.io>
  Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
  Jesper Madsen <jmad@itu.dk>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

Documentation/ioctl/ioctl-number.txt

@@ -149,6 +149,7 @@ Code  Seq#(hex)	Include File		Comments
 'K'	all	linux/kd.h
 'L'	00-1F	linux/loop.h		conflict!
 'L'	10-1F	drivers/scsi/mpt2sas/mpt2sas_ctl.h	conflict!
+'L'	20-2F	linux/lightnvm.h
 'L'	E0-FF	linux/ppdd.h		encrypted disk device driver
 					<http://linux01.gwdg.de/~alatham/ppdd.html>
 'M'	all	linux/soundcard.h	conflict!

MAINTAINERS

@@ -6243,6 +6243,14 @@ F:	drivers/nvdimm/pmem.c
 F:	include/linux/pmem.h
 F:	arch/*/include/asm/pmem.h
 
+LIGHTNVM PLATFORM SUPPORT
+M:	Matias Bjorling <mb@lightnvm.io>
+W:	http://github/OpenChannelSSD
+S:	Maintained
+F:	drivers/lightnvm/
+F:	include/linux/lightnvm.h
+F:	include/uapi/linux/lightnvm.h
+
 LINUX FOR IBM pSERIES (RS/6000)
 M:	Paul Mackerras <paulus@au.ibm.com>
 W:	http://www.ibm.com/linux/ltc/projects/ppc

drivers/Kconfig

@@ -44,6 +44,8 @@ source "drivers/net/Kconfig"
 
 source "drivers/isdn/Kconfig"
 
+source "drivers/lightnvm/Kconfig"
+
 # input before char - char/joystick depends on it. As does USB.
 
 source "drivers/input/Kconfig"

drivers/Makefile

@@ -70,6 +70,7 @@ obj-$(CONFIG_NUBUS)		+= nubus/
 obj-y				+= macintosh/
 obj-$(CONFIG_IDE)		+= ide/
 obj-$(CONFIG_SCSI)		+= scsi/
+obj-$(CONFIG_NVM)		+= lightnvm/
 obj-y				+= nvme/
 obj-$(CONFIG_ATA)		+= ata/
 obj-$(CONFIG_TARGET_CORE)	+= target/

drivers/lightnvm/Kconfig

+#
+# Open-Channel SSD NVM configuration
+#
+
+menuconfig NVM
+	bool "Open-Channel SSD target support"
+	depends on BLOCK
+	help
+	  Say Y here to get to enable Open-channel SSDs.
+
+	  Open-Channel SSDs implement a set of extension to SSDs, that
+	  exposes direct access to the underlying non-volatile memory.
+
+	  If you say N, all options in this submenu will be skipped and disabled
+	  only do this if you know what you are doing.
+
+if NVM
+
+config NVM_DEBUG
+	bool "Open-Channel SSD debugging support"
+	---help---
+	Exposes a debug management interface to create/remove targets at:
+
+	  /sys/module/lnvm/parameters/configure_debug
+
+	It is required to create/remove targets without IOCTLs.
+
+endif # NVM

drivers/lightnvm/Makefile

+#
+# Makefile for Open-Channel SSDs.
+#
+
+obj-$(CONFIG_NVM)		:= core.o

include/uapi/linux/lightnvm.h

+/*
+ * Copyright (C) 2015 CNEX Labs.  All rights reserved.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
+ * USA.
+ */
+
+#ifndef _UAPI_LINUX_LIGHTNVM_H
+#define _UAPI_LINUX_LIGHTNVM_H
+
+#ifdef __KERNEL__
+#include <linux/kernel.h>
+#include <linux/ioctl.h>
+#else /* __KERNEL__ */
+#include <stdio.h>
+#include <sys/ioctl.h>
+#define DISK_NAME_LEN 32
+#endif /* __KERNEL__ */
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define NVM_TTYPE_NAME_MAX 48
+#define NVM_TTYPE_MAX 63
+
+#define NVM_CTRL_FILE "/dev/lightnvm/control"
+
+struct nvm_ioctl_info_tgt {
+	__u32 version[3];
+	__u32 reserved;
+	char tgtname[NVM_TTYPE_NAME_MAX];
+};
+
+struct nvm_ioctl_info {
+	__u32 version[3];	/* in/out - major, minor, patch */
+	__u16 tgtsize;		/* number of targets */
+	__u16 reserved16;	/* pad to 4K page */
+	__u32 reserved[12];
+	struct nvm_ioctl_info_tgt tgts[NVM_TTYPE_MAX];
+};
+
+enum {
+	NVM_DEVICE_ACTIVE = 1 << 0,
+};
+
+struct nvm_ioctl_device_info {
+	char devname[DISK_NAME_LEN];
+	char bmname[NVM_TTYPE_NAME_MAX];
+	__u32 bmversion[3];
+	__u32 flags;
+	__u32 reserved[8];
+};
+
+struct nvm_ioctl_get_devices {
+	__u32 nr_devices;
+	__u32 reserved[31];
+	struct nvm_ioctl_device_info info[31];
+};
+
+struct nvm_ioctl_create_simple {
+	__u32 lun_begin;
+	__u32 lun_end;
+};
+
+enum {
+	NVM_CONFIG_TYPE_SIMPLE = 0,
+};
+
+struct nvm_ioctl_create_conf {
+	__u32 type;
+	union {
+		struct nvm_ioctl_create_simple s;
+	};
+};
+
+struct nvm_ioctl_create {
+	char dev[DISK_NAME_LEN];		/* open-channel SSD device */
+	char tgttype[NVM_TTYPE_NAME_MAX];	/* target type name */
+	char tgtname[DISK_NAME_LEN];		/* dev to expose target as */
+
+	__u32 flags;
+
+	struct nvm_ioctl_create_conf conf;
+};
+
+struct nvm_ioctl_remove {
+	char tgtname[DISK_NAME_LEN];
+
+	__u32 flags;
+};
+
+
+/* The ioctl type, 'L', 0x20 - 0x2F documented in ioctl-number.txt */
+enum {
+	/* top level cmds */
+	NVM_INFO_CMD = 0x20,
+	NVM_GET_DEVICES_CMD,
+
+	/* device level cmds */
+	NVM_DEV_CREATE_CMD,
+	NVM_DEV_REMOVE_CMD,
+};
+
+#define NVM_IOCTL 'L' /* 0x4c */
+
+#define NVM_INFO		_IOWR(NVM_IOCTL, NVM_INFO_CMD, \
+						struct nvm_ioctl_info)
+#define NVM_GET_DEVICES		_IOR(NVM_IOCTL, NVM_GET_DEVICES_CMD, \
+						struct nvm_ioctl_get_devices)
+#define NVM_DEV_CREATE		_IOW(NVM_IOCTL, NVM_DEV_CREATE_CMD, \
+						struct nvm_ioctl_create)
+#define NVM_DEV_REMOVE		_IOW(NVM_IOCTL, NVM_DEV_REMOVE_CMD, \
+						struct nvm_ioctl_remove)
+
+#define NVM_VERSION_MAJOR	1
+#define NVM_VERSION_MINOR	0
+#define NVM_VERSION_PATCHLEVEL	0
+
+#endif