/*
 * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License 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) KBUILD_MODNAME ": " fmt
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/async.h>
#include <linux/ndctl.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/mm.h>
#include "nd-core.h"

int nvdimm_major;
static int nvdimm_bus_major;
static struct class *nd_class;

struct bus_type nvdimm_bus_type = {
	.name = "nd",
};

int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus)
{
	dev_t devt = MKDEV(nvdimm_bus_major, nvdimm_bus->id);
	struct device *dev;

	dev = device_create(nd_class, &nvdimm_bus->dev, devt, nvdimm_bus,
			"ndctl%d", nvdimm_bus->id);

	if (IS_ERR(dev)) {
		dev_dbg(&nvdimm_bus->dev, "failed to register ndctl%d: %ld\n",
				nvdimm_bus->id, PTR_ERR(dev));
		return PTR_ERR(dev);
	}
	return 0;
}

void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus)
{
	device_destroy(nd_class, MKDEV(nvdimm_bus_major, nvdimm_bus->id));
}

static const struct nd_cmd_desc __nd_cmd_dimm_descs[] = {
	[ND_CMD_IMPLEMENTED] = { },
	[ND_CMD_SMART] = {
		.out_num = 2,
		.out_sizes = { 4, 8, },
	},
	[ND_CMD_SMART_THRESHOLD] = {
		.out_num = 2,
		.out_sizes = { 4, 8, },
	},
	[ND_CMD_DIMM_FLAGS] = {
		.out_num = 2,
		.out_sizes = { 4, 4 },
	},
	[ND_CMD_GET_CONFIG_SIZE] = {
		.out_num = 3,
		.out_sizes = { 4, 4, 4, },
	},
	[ND_CMD_GET_CONFIG_DATA] = {
		.in_num = 2,
		.in_sizes = { 4, 4, },
		.out_num = 2,
		.out_sizes = { 4, UINT_MAX, },
	},
	[ND_CMD_SET_CONFIG_DATA] = {
		.in_num = 3,
		.in_sizes = { 4, 4, UINT_MAX, },
		.out_num = 1,
		.out_sizes = { 4, },
	},
	[ND_CMD_VENDOR] = {
		.in_num = 3,
		.in_sizes = { 4, 4, UINT_MAX, },
		.out_num = 3,
		.out_sizes = { 4, 4, UINT_MAX, },
	},
};

const struct nd_cmd_desc *nd_cmd_dimm_desc(int cmd)
{
	if (cmd < ARRAY_SIZE(__nd_cmd_dimm_descs))
		return &__nd_cmd_dimm_descs[cmd];
	return NULL;
}
EXPORT_SYMBOL_GPL(nd_cmd_dimm_desc);

static const struct nd_cmd_desc __nd_cmd_bus_descs[] = {
	[ND_CMD_IMPLEMENTED] = { },
	[ND_CMD_ARS_CAP] = {
		.in_num = 2,
		.in_sizes = { 8, 8, },
		.out_num = 2,
		.out_sizes = { 4, 4, },
	},
	[ND_CMD_ARS_START] = {
		.in_num = 4,
		.in_sizes = { 8, 8, 2, 6, },
		.out_num = 1,
		.out_sizes = { 4, },
	},
	[ND_CMD_ARS_STATUS] = {
		.out_num = 2,
		.out_sizes = { 4, UINT_MAX, },
	},
};

const struct nd_cmd_desc *nd_cmd_bus_desc(int cmd)
{
	if (cmd < ARRAY_SIZE(__nd_cmd_bus_descs))
		return &__nd_cmd_bus_descs[cmd];
	return NULL;
}
EXPORT_SYMBOL_GPL(nd_cmd_bus_desc);

u32 nd_cmd_in_size(struct nvdimm *nvdimm, int cmd,
		const struct nd_cmd_desc *desc, int idx, void *buf)
{
	if (idx >= desc->in_num)
		return UINT_MAX;

	if (desc->in_sizes[idx] < UINT_MAX)
		return desc->in_sizes[idx];

	if (nvdimm && cmd == ND_CMD_SET_CONFIG_DATA && idx == 2) {
		struct nd_cmd_set_config_hdr *hdr = buf;

		return hdr->in_length;
	} else if (nvdimm && cmd == ND_CMD_VENDOR && idx == 2) {
		struct nd_cmd_vendor_hdr *hdr = buf;

		return hdr->in_length;
	}

	return UINT_MAX;
}
EXPORT_SYMBOL_GPL(nd_cmd_in_size);

u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
		const struct nd_cmd_desc *desc, int idx, const u32 *in_field,
		const u32 *out_field)
{
	if (idx >= desc->out_num)
		return UINT_MAX;

	if (desc->out_sizes[idx] < UINT_MAX)
		return desc->out_sizes[idx];

	if (nvdimm && cmd == ND_CMD_GET_CONFIG_DATA && idx == 1)
		return in_field[1];
	else if (nvdimm && cmd == ND_CMD_VENDOR && idx == 2)
		return out_field[1];
	else if (!nvdimm && cmd == ND_CMD_ARS_STATUS && idx == 1)
		return ND_CMD_ARS_STATUS_MAX;

	return UINT_MAX;
}
EXPORT_SYMBOL_GPL(nd_cmd_out_size);

static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
		int read_only, unsigned int ioctl_cmd, unsigned long arg)
{
	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
	size_t buf_len = 0, in_len = 0, out_len = 0;
	static char out_env[ND_CMD_MAX_ENVELOPE];
	static char in_env[ND_CMD_MAX_ENVELOPE];
	const struct nd_cmd_desc *desc = NULL;
	unsigned int cmd = _IOC_NR(ioctl_cmd);
	void __user *p = (void __user *) arg;
	struct device *dev = &nvdimm_bus->dev;
	const char *cmd_name, *dimm_name;
	unsigned long dsm_mask;
	void *buf;
	int rc, i;

	if (nvdimm) {
		desc = nd_cmd_dimm_desc(cmd);
		cmd_name = nvdimm_cmd_name(cmd);
		dsm_mask = nvdimm->dsm_mask ? *(nvdimm->dsm_mask) : 0;
		dimm_name = dev_name(&nvdimm->dev);
	} else {
		desc = nd_cmd_bus_desc(cmd);
		cmd_name = nvdimm_bus_cmd_name(cmd);
		dsm_mask = nd_desc->dsm_mask;
		dimm_name = "bus";
	}

	if (!desc || (desc->out_num + desc->in_num == 0) ||
			!test_bit(cmd, &dsm_mask))
		return -ENOTTY;

	/* fail write commands (when read-only) */
	if (read_only)
		switch (ioctl_cmd) {
		case ND_IOCTL_VENDOR:
		case ND_IOCTL_SET_CONFIG_DATA:
		case ND_IOCTL_ARS_START:
			dev_dbg(&nvdimm_bus->dev, "'%s' command while read-only.\n",
					nvdimm ? nvdimm_cmd_name(cmd)
					: nvdimm_bus_cmd_name(cmd));
			return -EPERM;
		default:
			break;
		}

	/* process an input envelope */
	for (i = 0; i < desc->in_num; i++) {
		u32 in_size, copy;

		in_size = nd_cmd_in_size(nvdimm, cmd, desc, i, in_env);
		if (in_size == UINT_MAX) {
			dev_err(dev, "%s:%s unknown input size cmd: %s field: %d\n",
					__func__, dimm_name, cmd_name, i);
			return -ENXIO;
		}
		if (!access_ok(VERIFY_READ, p + in_len, in_size))
			return -EFAULT;
		if (in_len < sizeof(in_env))
			copy = min_t(u32, sizeof(in_env) - in_len, in_size);
		else
			copy = 0;
		if (copy && copy_from_user(&in_env[in_len], p + in_len, copy))
			return -EFAULT;
		in_len += in_size;
	}

	/* process an output envelope */
	for (i = 0; i < desc->out_num; i++) {
		u32 out_size = nd_cmd_out_size(nvdimm, cmd, desc, i,
				(u32 *) in_env, (u32 *) out_env);
		u32 copy;

		if (out_size == UINT_MAX) {
			dev_dbg(dev, "%s:%s unknown output size cmd: %s field: %d\n",
					__func__, dimm_name, cmd_name, i);
			return -EFAULT;
		}
		if (!access_ok(VERIFY_WRITE, p + in_len + out_len, out_size))
			return -EFAULT;
		if (out_len < sizeof(out_env))
			copy = min_t(u32, sizeof(out_env) - out_len, out_size);
		else
			copy = 0;
		if (copy && copy_from_user(&out_env[out_len],
					p + in_len + out_len, copy))
			return -EFAULT;
		out_len += out_size;
	}

	buf_len = out_len + in_len;
	if (!access_ok(VERIFY_WRITE, p, sizeof(buf_len)))
		return -EFAULT;

	if (buf_len > ND_IOCTL_MAX_BUFLEN) {
		dev_dbg(dev, "%s:%s cmd: %s buf_len: %zu > %d\n", __func__,
				dimm_name, cmd_name, buf_len,
				ND_IOCTL_MAX_BUFLEN);
		return -EINVAL;
	}

	buf = vmalloc(buf_len);
	if (!buf)
		return -ENOMEM;

	if (copy_from_user(buf, p, buf_len)) {
		rc = -EFAULT;
		goto out;
	}

	rc = nd_desc->ndctl(nd_desc, nvdimm, cmd, buf, buf_len);
	if (rc < 0)
		goto out;
	if (copy_to_user(p, buf, buf_len))
		rc = -EFAULT;
 out:
	vfree(buf);
	return rc;
}

static long nd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	long id = (long) file->private_data;
	int rc = -ENXIO, read_only;
	struct nvdimm_bus *nvdimm_bus;

	read_only = (O_RDWR != (file->f_flags & O_ACCMODE));
	mutex_lock(&nvdimm_bus_list_mutex);
	list_for_each_entry(nvdimm_bus, &nvdimm_bus_list, list) {
		if (nvdimm_bus->id == id) {
			rc = __nd_ioctl(nvdimm_bus, NULL, read_only, cmd, arg);
			break;
		}
	}
	mutex_unlock(&nvdimm_bus_list_mutex);

	return rc;
}

static int match_dimm(struct device *dev, void *data)
{
	long id = (long) data;

	if (is_nvdimm(dev)) {
		struct nvdimm *nvdimm = to_nvdimm(dev);

		return nvdimm->id == id;
	}

	return 0;
}

static long nvdimm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	int rc = -ENXIO, read_only;
	struct nvdimm_bus *nvdimm_bus;

	read_only = (O_RDWR != (file->f_flags & O_ACCMODE));
	mutex_lock(&nvdimm_bus_list_mutex);
	list_for_each_entry(nvdimm_bus, &nvdimm_bus_list, list) {
		struct device *dev = device_find_child(&nvdimm_bus->dev,
				file->private_data, match_dimm);
		struct nvdimm *nvdimm;

		if (!dev)
			continue;

		nvdimm = to_nvdimm(dev);
		rc = __nd_ioctl(nvdimm_bus, nvdimm, read_only, cmd, arg);
		put_device(dev);
		break;
	}
	mutex_unlock(&nvdimm_bus_list_mutex);

	return rc;
}

static int nd_open(struct inode *inode, struct file *file)
{
	long minor = iminor(inode);

	file->private_data = (void *) minor;
	return 0;
}

static const struct file_operations nvdimm_bus_fops = {
	.owner = THIS_MODULE,
	.open = nd_open,
	.unlocked_ioctl = nd_ioctl,
	.compat_ioctl = nd_ioctl,
	.llseek = noop_llseek,
};

static const struct file_operations nvdimm_fops = {
	.owner = THIS_MODULE,
	.open = nd_open,
	.unlocked_ioctl = nvdimm_ioctl,
	.compat_ioctl = nvdimm_ioctl,
	.llseek = noop_llseek,
};

int __init nvdimm_bus_init(void)
{
	int rc;

	rc = bus_register(&nvdimm_bus_type);
	if (rc)
		return rc;

	rc = register_chrdev(0, "ndctl", &nvdimm_bus_fops);
	if (rc < 0)
		goto err_bus_chrdev;
	nvdimm_bus_major = rc;

	rc = register_chrdev(0, "dimmctl", &nvdimm_fops);
	if (rc < 0)
		goto err_dimm_chrdev;
	nvdimm_major = rc;

	nd_class = class_create(THIS_MODULE, "nd");
	if (IS_ERR(nd_class))
		goto err_class;

	return 0;

 err_class:
	unregister_chrdev(nvdimm_major, "dimmctl");
 err_dimm_chrdev:
	unregister_chrdev(nvdimm_bus_major, "ndctl");
 err_bus_chrdev:
	bus_unregister(&nvdimm_bus_type);

	return rc;
}

void __exit nvdimm_bus_exit(void)
{
	class_destroy(nd_class);
	unregister_chrdev(nvdimm_bus_major, "ndctl");
	unregister_chrdev(nvdimm_major, "dimmctl");
	bus_unregister(&nvdimm_bus_type);
}