1 files changed, 826 insertions, 0 deletions

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
new file mode 100644
index 000000000000..f659e605a406
--- /dev/null
+++ b/drivers/lightnvm/core.c
@@ -0,0 +1,826 @@
+/*
+ * Copyright (C) 2015 IT University of Copenhagen. All rights reserved.
+ * Initial release: Matias Bjorling <m@bjorling.me>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/sem.h>
+#include <linux/bitmap.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/lightnvm.h>
+#include <uapi/linux/lightnvm.h>
+
+static LIST_HEAD(nvm_targets);
+static LIST_HEAD(nvm_mgrs);
+static LIST_HEAD(nvm_devices);
+static DECLARE_RWSEM(nvm_lock);
+
+static struct nvm_tgt_type *nvm_find_target_type(const char *name)
+{
+	struct nvm_tgt_type *tt;
+
+	list_for_each_entry(tt, &nvm_targets, list)
+		if (!strcmp(name, tt->name))
+			return tt;
+
+	return NULL;
+}
+
+int nvm_register_target(struct nvm_tgt_type *tt)
+{
+	int ret = 0;
+
+	down_write(&nvm_lock);
+	if (nvm_find_target_type(tt->name))
+		ret = -EEXIST;
+	else
+		list_add(&tt->list, &nvm_targets);
+	up_write(&nvm_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(nvm_register_target);
+
+void nvm_unregister_target(struct nvm_tgt_type *tt)
+{
+	if (!tt)
+		return;
+
+	down_write(&nvm_lock);
+	list_del(&tt->list);
+	up_write(&nvm_lock);
+}
+EXPORT_SYMBOL(nvm_unregister_target);
+
+void *nvm_dev_dma_alloc(struct nvm_dev *dev, gfp_t mem_flags,
+							dma_addr_t *dma_handler)
+{
+	return dev->ops->dev_dma_alloc(dev->q, dev->ppalist_pool, mem_flags,
+								dma_handler);
+}
+EXPORT_SYMBOL(nvm_dev_dma_alloc);
+
+void nvm_dev_dma_free(struct nvm_dev *dev, void *ppa_list,
+							dma_addr_t dma_handler)
+{
+	dev->ops->dev_dma_free(dev->ppalist_pool, ppa_list, dma_handler);
+}
+EXPORT_SYMBOL(nvm_dev_dma_free);
+
+static struct nvmm_type *nvm_find_mgr_type(const char *name)
+{
+	struct nvmm_type *mt;
+
+	list_for_each_entry(mt, &nvm_mgrs, list)
+		if (!strcmp(name, mt->name))
+			return mt;
+
+	return NULL;
+}
+
+int nvm_register_mgr(struct nvmm_type *mt)
+{
+	int ret = 0;
+
+	down_write(&nvm_lock);
+	if (nvm_find_mgr_type(mt->name))
+		ret = -EEXIST;
+	else
+		list_add(&mt->list, &nvm_mgrs);
+	up_write(&nvm_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(nvm_register_mgr);
+
+void nvm_unregister_mgr(struct nvmm_type *mt)
+{
+	if (!mt)
+		return;
+
+	down_write(&nvm_lock);
+	list_del(&mt->list);
+	up_write(&nvm_lock);
+}
+EXPORT_SYMBOL(nvm_unregister_mgr);
+
+static struct nvm_dev *nvm_find_nvm_dev(const char *name)
+{
+	struct nvm_dev *dev;
+
+	list_for_each_entry(dev, &nvm_devices, devices)
+		if (!strcmp(name, dev->name))
+			return dev;
+
+	return NULL;
+}
+
+struct nvm_block *nvm_get_blk(struct nvm_dev *dev, struct nvm_lun *lun,
+							unsigned long flags)
+{
+	return dev->mt->get_blk(dev, lun, flags);
+}
+EXPORT_SYMBOL(nvm_get_blk);
+
+/* Assumes that all valid pages have already been moved on release to bm */
+void nvm_put_blk(struct nvm_dev *dev, struct nvm_block *blk)
+{
+	return dev->mt->put_blk(dev, blk);
+}
+EXPORT_SYMBOL(nvm_put_blk);
+
+int nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	return dev->mt->submit_io(dev, rqd);
+}
+EXPORT_SYMBOL(nvm_submit_io);
+
+int nvm_erase_blk(struct nvm_dev *dev, struct nvm_block *blk)
+{
+	return dev->mt->erase_blk(dev, blk, 0);
+}
+EXPORT_SYMBOL(nvm_erase_blk);
+
+static void nvm_core_free(struct nvm_dev *dev)
+{
+	kfree(dev);
+}
+
+static int nvm_core_init(struct nvm_dev *dev)
+{
+	struct nvm_id *id = &dev->identity;
+	struct nvm_id_group *grp = &id->groups[0];
+
+	/* device values */
+	dev->nr_chnls = grp->num_ch;
+	dev->luns_per_chnl = grp->num_lun;
+	dev->pgs_per_blk = grp->num_pg;
+	dev->blks_per_lun = grp->num_blk;
+	dev->nr_planes = grp->num_pln;
+	dev->sec_size = grp->csecs;
+	dev->oob_size = grp->sos;
+	dev->sec_per_pg = grp->fpg_sz / grp->csecs;
+	dev->addr_mode = id->ppat;
+	dev->addr_format = id->ppaf;
+
+	dev->plane_mode = NVM_PLANE_SINGLE;
+	dev->max_rq_size = dev->ops->max_phys_sect * dev->sec_size;
+
+	if (grp->mpos & 0x020202)
+		dev->plane_mode = NVM_PLANE_DOUBLE;
+	if (grp->mpos & 0x040404)
+		dev->plane_mode = NVM_PLANE_QUAD;
+
+	/* calculated values */
+	dev->sec_per_pl = dev->sec_per_pg * dev->nr_planes;
+	dev->sec_per_blk = dev->sec_per_pl * dev->pgs_per_blk;
+	dev->sec_per_lun = dev->sec_per_blk * dev->blks_per_lun;
+	dev->nr_luns = dev->luns_per_chnl * dev->nr_chnls;
+
+	dev->total_blocks = dev->nr_planes *
+				dev->blks_per_lun *
+				dev->luns_per_chnl *
+				dev->nr_chnls;
+	dev->total_pages = dev->total_blocks * dev->pgs_per_blk;
+	INIT_LIST_HEAD(&dev->online_targets);
+
+	return 0;
+}
+
+static void nvm_free(struct nvm_dev *dev)
+{
+	if (!dev)
+		return;
+
+	if (dev->mt)
+		dev->mt->unregister_mgr(dev);
+
+	nvm_core_free(dev);
+}
+
+static int nvm_init(struct nvm_dev *dev)
+{
+	struct nvmm_type *mt;
+	int ret = 0;
+
+	if (!dev->q || !dev->ops)
+		return -EINVAL;
+
+	if (dev->ops->identity(dev->q, &dev->identity)) {
+		pr_err("nvm: device could not be identified\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	pr_debug("nvm: ver:%x nvm_vendor:%x groups:%u\n",
+			dev->identity.ver_id, dev->identity.vmnt,
+							dev->identity.cgrps);
+
+	if (dev->identity.ver_id != 1) {
+		pr_err("nvm: device not supported by kernel.");
+		goto err;
+	}
+
+	if (dev->identity.cgrps != 1) {
+		pr_err("nvm: only one group configuration supported.");
+		goto err;
+	}
+
+	ret = nvm_core_init(dev);
+	if (ret) {
+		pr_err("nvm: could not initialize core structures.\n");
+		goto err;
+	}
+
+	/* register with device with a supported manager */
+	list_for_each_entry(mt, &nvm_mgrs, list) {
+		ret = mt->register_mgr(dev);
+		if (ret < 0)
+			goto err; /* initialization failed */
+		if (ret > 0) {
+			dev->mt = mt;
+			break; /* successfully initialized */
+		}
+	}
+
+	if (!ret) {
+		pr_info("nvm: no compatible manager found.\n");
+		return 0;
+	}
+
+	pr_info("nvm: registered %s [%u/%u/%u/%u/%u/%u]\n",
+			dev->name, dev->sec_per_pg, dev->nr_planes,
+			dev->pgs_per_blk, dev->blks_per_lun, dev->nr_luns,
+			dev->nr_chnls);
+	return 0;
+err:
+	nvm_free(dev);
+	pr_err("nvm: failed to initialize nvm\n");
+	return ret;
+}
+
+static void nvm_exit(struct nvm_dev *dev)
+{
+	if (dev->ppalist_pool)
+		dev->ops->destroy_dma_pool(dev->ppalist_pool);
+	nvm_free(dev);
+
+	pr_info("nvm: successfully unloaded\n");
+}
+
+int nvm_register(struct request_queue *q, char *disk_name,
+							struct nvm_dev_ops *ops)
+{
+	struct nvm_dev *dev;
+	int ret;
+
+	if (!ops->identity)
+		return -EINVAL;
+
+	dev = kzalloc(sizeof(struct nvm_dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->q = q;
+	dev->ops = ops;
+	strncpy(dev->name, disk_name, DISK_NAME_LEN);
+
+	ret = nvm_init(dev);
+	if (ret)
+		goto err_init;
+
+	down_write(&nvm_lock);
+	list_add(&dev->devices, &nvm_devices);
+	up_write(&nvm_lock);
+
+	if (dev->ops->max_phys_sect > 1) {
+		dev->ppalist_pool = dev->ops->create_dma_pool(dev->q,
+								"ppalist");
+		if (!dev->ppalist_pool) {
+			pr_err("nvm: could not create ppa pool\n");
+			return -ENOMEM;
+		}
+	} else if (dev->ops->max_phys_sect > 256) {
+		pr_info("nvm: max sectors supported is 256.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+err_init:
+	kfree(dev);
+	return ret;
+}
+EXPORT_SYMBOL(nvm_register);
+
+void nvm_unregister(char *disk_name)
+{
+	struct nvm_dev *dev = nvm_find_nvm_dev(disk_name);
+
+	if (!dev) {
+		pr_err("nvm: could not find device %s to unregister\n",
+								disk_name);
+		return;
+	}
+
+	nvm_exit(dev);
+
+	down_write(&nvm_lock);
+	list_del(&dev->devices);
+	up_write(&nvm_lock);
+}
+EXPORT_SYMBOL(nvm_unregister);
+
+static const struct block_device_operations nvm_fops = {
+	.owner		= THIS_MODULE,
+};
+
+static int nvm_create_target(struct nvm_dev *dev,
+						struct nvm_ioctl_create *create)
+{
+	struct nvm_ioctl_create_simple *s = &create->conf.s;
+	struct request_queue *tqueue;
+	struct nvmm_type *mt;
+	struct gendisk *tdisk;
+	struct nvm_tgt_type *tt;
+	struct nvm_target *t;
+	void *targetdata;
+	int ret = 0;
+
+	if (!dev->mt) {
+		/* register with device with a supported NVM manager */
+		list_for_each_entry(mt, &nvm_mgrs, list) {
+			ret = mt->register_mgr(dev);
+			if (ret < 0)
+				return ret; /* initialization failed */
+			if (ret > 0) {
+				dev->mt = mt;
+				break; /* successfully initialized */
+			}
+		}
+
+		if (!ret) {
+			pr_info("nvm: no compatible nvm manager found.\n");
+			return -ENODEV;
+		}
+	}
+
+	tt = nvm_find_target_type(create->tgttype);
+	if (!tt) {
+		pr_err("nvm: target type %s not found\n", create->tgttype);
+		return -EINVAL;
+	}
+
+	down_write(&nvm_lock);
+	list_for_each_entry(t, &dev->online_targets, list) {
+		if (!strcmp(create->tgtname, t->disk->disk_name)) {
+			pr_err("nvm: target name already exists.\n");
+			up_write(&nvm_lock);
+			return -EINVAL;
+		}
+	}
+	up_write(&nvm_lock);
+
+	t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);
+	if (!t)
+		return -ENOMEM;
+
+	tqueue = blk_alloc_queue_node(GFP_KERNEL, dev->q->node);
+	if (!tqueue)
+		goto err_t;
+	blk_queue_make_request(tqueue, tt->make_rq);
+
+	tdisk = alloc_disk(0);
+	if (!tdisk)
+		goto err_queue;
+
+	sprintf(tdisk->disk_name, "%s", create->tgtname);
+	tdisk->flags = GENHD_FL_EXT_DEVT;
+	tdisk->major = 0;
+	tdisk->first_minor = 0;
+	tdisk->fops = &nvm_fops;
+	tdisk->queue = tqueue;
+
+	targetdata = tt->init(dev, tdisk, s->lun_begin, s->lun_end);
+	if (IS_ERR(targetdata))
+		goto err_init;
+
+	tdisk->private_data = targetdata;
+	tqueue->queuedata = targetdata;
+
+	blk_queue_max_hw_sectors(tqueue, 8 * dev->ops->max_phys_sect);
+
+	set_capacity(tdisk, tt->capacity(targetdata));
+	add_disk(tdisk);
+
+	t->type = tt;
+	t->disk = tdisk;
+
+	down_write(&nvm_lock);
+	list_add_tail(&t->list, &dev->online_targets);
+	up_write(&nvm_lock);
+
+	return 0;
+err_init:
+	put_disk(tdisk);
+err_queue:
+	blk_cleanup_queue(tqueue);
+err_t:
+	kfree(t);
+	return -ENOMEM;
+}
+
+static void nvm_remove_target(struct nvm_target *t)
+{
+	struct nvm_tgt_type *tt = t->type;
+	struct gendisk *tdisk = t->disk;
+	struct request_queue *q = tdisk->queue;
+
+	lockdep_assert_held(&nvm_lock);
+
+	del_gendisk(tdisk);
+	if (tt->exit)
+		tt->exit(tdisk->private_data);
+
+	blk_cleanup_queue(q);
+
+	put_disk(tdisk);
+
+	list_del(&t->list);
+	kfree(t);
+}
+
+static int __nvm_configure_create(struct nvm_ioctl_create *create)
+{
+	struct nvm_dev *dev;
+	struct nvm_ioctl_create_simple *s;
+
+	dev = nvm_find_nvm_dev(create->dev);
+	if (!dev) {
+		pr_err("nvm: device not found\n");
+		return -EINVAL;
+	}
+
+	if (create->conf.type != NVM_CONFIG_TYPE_SIMPLE) {
+		pr_err("nvm: config type not valid\n");
+		return -EINVAL;
+	}
+	s = &create->conf.s;
+
+	if (s->lun_begin > s->lun_end || s->lun_end > dev->nr_luns) {
+		pr_err("nvm: lun out of bound (%u:%u > %u)\n",
+			s->lun_begin, s->lun_end, dev->nr_luns);
+		return -EINVAL;
+	}
+
+	return nvm_create_target(dev, create);
+}
+
+static int __nvm_configure_remove(struct nvm_ioctl_remove *remove)
+{
+	struct nvm_target *t = NULL;
+	struct nvm_dev *dev;
+	int ret = -1;
+
+	down_write(&nvm_lock);
+	list_for_each_entry(dev, &nvm_devices, devices)
+		list_for_each_entry(t, &dev->online_targets, list) {
+			if (!strcmp(remove->tgtname, t->disk->disk_name)) {
+				nvm_remove_target(t);
+				ret = 0;
+				break;
+			}
+		}
+	up_write(&nvm_lock);
+
+	if (ret) {
+		pr_err("nvm: target \"%s\" doesn't exist.\n", remove->tgtname);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_NVM_DEBUG
+static int nvm_configure_show(const char *val)
+{
+	struct nvm_dev *dev;
+	char opcode, devname[DISK_NAME_LEN];
+	int ret;
+
+	ret = sscanf(val, "%c %32s", &opcode, devname);
+	if (ret != 2) {
+		pr_err("nvm: invalid command. Use \"opcode devicename\".\n");
+		return -EINVAL;
+	}
+
+	dev = nvm_find_nvm_dev(devname);
+	if (!dev) {
+		pr_err("nvm: device not found\n");
+		return -EINVAL;
+	}
+
+	if (!dev->mt)
+		return 0;
+
+	dev->mt->free_blocks_print(dev);
+
+	return 0;
+}
+
+static int nvm_configure_remove(const char *val)
+{
+	struct nvm_ioctl_remove remove;
+	char opcode;
+	int ret;
+
+	ret = sscanf(val, "%c %256s", &opcode, remove.tgtname);
+	if (ret != 2) {
+		pr_err("nvm: invalid command. Use \"d targetname\".\n");
+		return -EINVAL;
+	}
+
+	remove.flags = 0;
+
+	return __nvm_configure_remove(&remove);
+}
+
+static int nvm_configure_create(const char *val)
+{
+	struct nvm_ioctl_create create;
+	char opcode;
+	int lun_begin, lun_end, ret;
+
+	ret = sscanf(val, "%c %256s %256s %48s %u:%u", &opcode, create.dev,
+						create.tgtname, create.tgttype,
+						&lun_begin, &lun_end);
+	if (ret != 6) {
+		pr_err("nvm: invalid command. Use \"opcode device name tgttype lun_begin:lun_end\".\n");
+		return -EINVAL;
+	}
+
+	create.flags = 0;
+	create.conf.type = NVM_CONFIG_TYPE_SIMPLE;
+	create.conf.s.lun_begin = lun_begin;
+	create.conf.s.lun_end = lun_end;
+
+	return __nvm_configure_create(&create);
+}
+
+
+/* Exposes administrative interface through /sys/module/lnvm/configure_by_str */
+static int nvm_configure_by_str_event(const char *val,
+					const struct kernel_param *kp)
+{
+	char opcode;
+	int ret;
+
+	ret = sscanf(val, "%c", &opcode);
+	if (ret != 1) {
+		pr_err("nvm: string must have the format of \"cmd ...\"\n");
+		return -EINVAL;
+	}
+
+	switch (opcode) {
+	case 'a':
+		return nvm_configure_create(val);
+	case 'd':
+		return nvm_configure_remove(val);
+	case 's':
+		return nvm_configure_show(val);
+	default:
+		pr_err("nvm: invalid command\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int nvm_configure_get(char *buf, const struct kernel_param *kp)
+{
+	int sz = 0;
+	char *buf_start = buf;
+	struct nvm_dev *dev;
+
+	buf += sprintf(buf, "available devices:\n");
+	down_write(&nvm_lock);
+	list_for_each_entry(dev, &nvm_devices, devices) {
+		if (sz > 4095 - DISK_NAME_LEN)
+			break;
+		buf += sprintf(buf, " %32s\n", dev->name);
+	}
+	up_write(&nvm_lock);
+
+	return buf - buf_start - 1;
+}
+
+static const struct kernel_param_ops nvm_configure_by_str_event_param_ops = {
+	.set	= nvm_configure_by_str_event,
+	.get	= nvm_configure_get,
+};
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX	"lnvm."
+
+module_param_cb(configure_debug, &nvm_configure_by_str_event_param_ops, NULL,
+									0644);
+
+#endif /* CONFIG_NVM_DEBUG */
+
+static long nvm_ioctl_info(struct file *file, void __user *arg)
+{
+	struct nvm_ioctl_info *info;
+	struct nvm_tgt_type *tt;
+	int tgt_iter = 0;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	info = memdup_user(arg, sizeof(struct nvm_ioctl_info));
+	if (IS_ERR(info))
+		return -EFAULT;
+
+	info->version[0] = NVM_VERSION_MAJOR;
+	info->version[1] = NVM_VERSION_MINOR;
+	info->version[2] = NVM_VERSION_PATCH;
+
+	down_write(&nvm_lock);
+	list_for_each_entry(tt, &nvm_targets, list) {
+		struct nvm_ioctl_info_tgt *tgt = &info->tgts[tgt_iter];
+
+		tgt->version[0] = tt->version[0];
+		tgt->version[1] = tt->version[1];
+		tgt->version[2] = tt->version[2];
+		strncpy(tgt->tgtname, tt->name, NVM_TTYPE_NAME_MAX);
+
+		tgt_iter++;
+	}
+
+	info->tgtsize = tgt_iter;
+	up_write(&nvm_lock);
+
+	if (copy_to_user(arg, info, sizeof(struct nvm_ioctl_info)))
+		return -EFAULT;
+
+	kfree(info);
+	return 0;
+}
+
+static long nvm_ioctl_get_devices(struct file *file, void __user *arg)
+{
+	struct nvm_ioctl_get_devices *devices;
+	struct nvm_dev *dev;
+	int i = 0;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	devices = kzalloc(sizeof(struct nvm_ioctl_get_devices), GFP_KERNEL);
+	if (!devices)
+		return -ENOMEM;
+
+	down_write(&nvm_lock);
+	list_for_each_entry(dev, &nvm_devices, devices) {
+		struct nvm_ioctl_device_info *info = &devices->info[i];
+
+		sprintf(info->devname, "%s", dev->name);
+		if (dev->mt) {
+			info->bmversion[0] = dev->mt->version[0];
+			info->bmversion[1] = dev->mt->version[1];
+			info->bmversion[2] = dev->mt->version[2];
+			sprintf(info->bmname, "%s", dev->mt->name);
+		} else {
+			sprintf(info->bmname, "none");
+		}
+
+		i++;
+		if (i > 31) {
+			pr_err("nvm: max 31 devices can be reported.\n");
+			break;
+		}
+	}
+	up_write(&nvm_lock);
+
+	devices->nr_devices = i;
+
+	if (copy_to_user(arg, devices, sizeof(struct nvm_ioctl_get_devices)))
+		return -EFAULT;
+
+	kfree(devices);
+	return 0;
+}
+
+static long nvm_ioctl_dev_create(struct file *file, void __user *arg)
+{
+	struct nvm_ioctl_create create;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(&create, arg, sizeof(struct nvm_ioctl_create)))
+		return -EFAULT;
+
+	create.dev[DISK_NAME_LEN - 1] = '\0';
+	create.tgttype[NVM_TTYPE_NAME_MAX - 1] = '\0';
+	create.tgtname[DISK_NAME_LEN - 1] = '\0';
+
+	if (create.flags != 0) {
+		pr_err("nvm: no flags supported\n");
+		return -EINVAL;
+	}
+
+	return __nvm_configure_create(&create);
+}
+
+static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
+{
+	struct nvm_ioctl_remove remove;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(&remove, arg, sizeof(struct nvm_ioctl_remove)))
+		return -EFAULT;
+
+	remove.tgtname[DISK_NAME_LEN - 1] = '\0';
+
+	if (remove.flags != 0) {
+		pr_err("nvm: no flags supported\n");
+		return -EINVAL;
+	}
+
+	return __nvm_configure_remove(&remove);
+}
+
+static long nvm_ctl_ioctl(struct file *file, uint cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+
+	switch (cmd) {
+	case NVM_INFO:
+		return nvm_ioctl_info(file, argp);
+	case NVM_GET_DEVICES:
+		return nvm_ioctl_get_devices(file, argp);
+	case NVM_DEV_CREATE:
+		return nvm_ioctl_dev_create(file, argp);
+	case NVM_DEV_REMOVE:
+		return nvm_ioctl_dev_remove(file, argp);
+	}
+	return 0;
+}
+
+static const struct file_operations _ctl_fops = {
+	.open = nonseekable_open,
+	.unlocked_ioctl = nvm_ctl_ioctl,
+	.owner = THIS_MODULE,
+	.llseek  = noop_llseek,
+};
+
+static struct miscdevice _nvm_misc = {
+	.minor		= MISC_DYNAMIC_MINOR,
+	.name		= "lightnvm",
+	.nodename	= "lightnvm/control",
+	.fops		= &_ctl_fops,
+};
+
+MODULE_ALIAS_MISCDEV(MISC_DYNAMIC_MINOR);
+
+static int __init nvm_mod_init(void)
+{
+	int ret;
+
+	ret = misc_register(&_nvm_misc);
+	if (ret)
+		pr_err("nvm: misc_register failed for control device");
+
+	return ret;
+}
+
+static void __exit nvm_mod_exit(void)
+{
+	misc_deregister(&_nvm_misc);
+}
+
+MODULE_AUTHOR("Matias Bjorling <m@bjorling.me>");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("0.1");
+module_init(nvm_mod_init);
+module_exit(nvm_mod_exit);