/*
 * 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/device.h>
#include <linux/ndctl.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include "nd-core.h"
#include "label.h"
#include "nd.h"

static DEFINE_IDA(dimm_ida);

/*
 * Retrieve bus and dimm handle and return if this bus supports
 * get_config_data commands
 */
static int __validate_dimm(struct nvdimm_drvdata *ndd)
{
	struct nvdimm *nvdimm;

	if (!ndd)
		return -EINVAL;

	nvdimm = to_nvdimm(ndd->dev);

	if (!nvdimm->cmd_mask)
		return -ENXIO;
	if (!test_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm->cmd_mask))
		return -ENXIO;

	return 0;
}

static int validate_dimm(struct nvdimm_drvdata *ndd)
{
	int rc = __validate_dimm(ndd);

	if (rc && ndd)
		dev_dbg(ndd->dev, "%pf: %s error: %d\n",
				__builtin_return_address(0), __func__, rc);
	return rc;
}

/**
 * nvdimm_init_nsarea - determine the geometry of a dimm's namespace area
 * @nvdimm: dimm to initialize
 */
int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd)
{
	struct nd_cmd_get_config_size *cmd = &ndd->nsarea;
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
	struct nvdimm_bus_descriptor *nd_desc;
	int rc = validate_dimm(ndd);

	if (rc)
		return rc;

	if (cmd->config_size)
		return 0; /* already valid */

	memset(cmd, 0, sizeof(*cmd));
	nd_desc = nvdimm_bus->nd_desc;
	return nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
			ND_CMD_GET_CONFIG_SIZE, cmd, sizeof(*cmd), NULL);
}

int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
{
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
	struct nd_cmd_get_config_data_hdr *cmd;
	struct nvdimm_bus_descriptor *nd_desc;
	int rc = validate_dimm(ndd);
	u32 max_cmd_size, config_size;
	size_t offset;

	if (rc)
		return rc;

	if (ndd->data)
		return 0;

	if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0
			|| ndd->nsarea.config_size < ND_LABEL_MIN_SIZE) {
		dev_dbg(ndd->dev, "failed to init config data area: (%d:%d)\n",
				ndd->nsarea.max_xfer, ndd->nsarea.config_size);
		return -ENXIO;
	}

	ndd->data = kmalloc(ndd->nsarea.config_size, GFP_KERNEL);
	if (!ndd->data)
		ndd->data = vmalloc(ndd->nsarea.config_size);

	if (!ndd->data)
		return -ENOMEM;

	max_cmd_size = min_t(u32, PAGE_SIZE, ndd->nsarea.max_xfer);
	cmd = kzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
	if (!cmd)
		return -ENOMEM;

	nd_desc = nvdimm_bus->nd_desc;
	for (config_size = ndd->nsarea.config_size, offset = 0;
			config_size; config_size -= cmd->in_length,
			offset += cmd->in_length) {
		cmd->in_length = min(config_size, max_cmd_size);
		cmd->in_offset = offset;
		rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
				ND_CMD_GET_CONFIG_DATA, cmd,
				cmd->in_length + sizeof(*cmd), NULL);
		if (rc || cmd->status) {
			rc = -ENXIO;
			break;
		}
		memcpy(ndd->data + offset, cmd->out_buf, cmd->in_length);
	}
	dev_dbg(ndd->dev, "%s: len: %zu rc: %d\n", __func__, offset, rc);
	kfree(cmd);

	return rc;
}

int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
		void *buf, size_t len)
{
	int rc = validate_dimm(ndd);
	size_t max_cmd_size, buf_offset;
	struct nd_cmd_set_config_hdr *cmd;
	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;

	if (rc)
		return rc;

	if (!ndd->data)
		return -ENXIO;

	if (offset + len > ndd->nsarea.config_size)
		return -ENXIO;

	max_cmd_size = min_t(u32, PAGE_SIZE, len);
	max_cmd_size = min_t(u32, max_cmd_size, ndd->nsarea.max_xfer);
	cmd = kzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
	if (!cmd)
		return -ENOMEM;

	for (buf_offset = 0; len; len -= cmd->in_length,
			buf_offset += cmd->in_length) {
		size_t cmd_size;
		u32 *status;

		cmd->in_offset = offset + buf_offset;
		cmd->in_length = min(max_cmd_size, len);
		memcpy(cmd->in_buf, buf + buf_offset, cmd->in_length);

		/* status is output in the last 4-bytes of the command buffer */
		cmd_size = sizeof(*cmd) + cmd->in_length + sizeof(u32);
		status = ((void *) cmd) + cmd_size - sizeof(u32);

		rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
				ND_CMD_SET_CONFIG_DATA, cmd, cmd_size, NULL);
		if (rc || *status) {
			rc = rc ? rc : -ENXIO;
			break;
		}
	}
	kfree(cmd);

	return rc;
}

static void nvdimm_release(struct device *dev)
{
	struct nvdimm *nvdimm = to_nvdimm(dev);

	ida_simple_remove(&dimm_ida, nvdimm->id);
	kfree(nvdimm);
}

static struct device_type nvdimm_device_type = {
	.name = "nvdimm",
	.release = nvdimm_release,
};

bool is_nvdimm(struct device *dev)
{
	return dev->type == &nvdimm_device_type;
}

struct nvdimm *to_nvdimm(struct device *dev)
{
	struct nvdimm *nvdimm = container_of(dev, struct nvdimm, dev);

	WARN_ON(!is_nvdimm(dev));
	return nvdimm;
}
EXPORT_SYMBOL_GPL(to_nvdimm);

struct nvdimm *nd_blk_region_to_dimm(struct nd_blk_region *ndbr)
{
	struct nd_region *nd_region = &ndbr->nd_region;
	struct nd_mapping *nd_mapping = &nd_region->mapping[0];

	return nd_mapping->nvdimm;
}
EXPORT_SYMBOL_GPL(nd_blk_region_to_dimm);

struct nvdimm_drvdata *to_ndd(struct nd_mapping *nd_mapping)
{
	struct nvdimm *nvdimm = nd_mapping->nvdimm;

	WARN_ON_ONCE(!is_nvdimm_bus_locked(&nvdimm->dev));

	return dev_get_drvdata(&nvdimm->dev);
}
EXPORT_SYMBOL(to_ndd);

void nvdimm_drvdata_release(struct kref *kref)
{
	struct nvdimm_drvdata *ndd = container_of(kref, typeof(*ndd), kref);
	struct device *dev = ndd->dev;
	struct resource *res, *_r;

	dev_dbg(dev, "%s\n", __func__);

	nvdimm_bus_lock(dev);
	for_each_dpa_resource_safe(ndd, res, _r)
		nvdimm_free_dpa(ndd, res);
	nvdimm_bus_unlock(dev);

	kvfree(ndd->data);
	kfree(ndd);
	put_device(dev);
}

void get_ndd(struct nvdimm_drvdata *ndd)
{
	kref_get(&ndd->kref);
}

void put_ndd(struct nvdimm_drvdata *ndd)
{
	if (ndd)
		kref_put(&ndd->kref, nvdimm_drvdata_release);
}

const char *nvdimm_name(struct nvdimm *nvdimm)
{
	return dev_name(&nvdimm->dev);
}
EXPORT_SYMBOL_GPL(nvdimm_name);

unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm)
{
	return nvdimm->cmd_mask;
}
EXPORT_SYMBOL_GPL(nvdimm_cmd_mask);

void *nvdimm_provider_data(struct nvdimm *nvdimm)
{
	if (nvdimm)
		return nvdimm->provider_data;
	return NULL;
}
EXPORT_SYMBOL_GPL(nvdimm_provider_data);

static ssize_t commands_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nvdimm *nvdimm = to_nvdimm(dev);
	int cmd, len = 0;

	if (!nvdimm->cmd_mask)
		return sprintf(buf, "\n");

	for_each_set_bit(cmd, &nvdimm->cmd_mask, BITS_PER_LONG)
		len += sprintf(buf + len, "%s ", nvdimm_cmd_name(cmd));
	len += sprintf(buf + len, "\n");
	return len;
}
static DEVICE_ATTR_RO(commands);

static ssize_t state_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct nvdimm *nvdimm = to_nvdimm(dev);

	/*
	 * The state may be in the process of changing, userspace should
	 * quiesce probing if it wants a static answer
	 */
	nvdimm_bus_lock(dev);
	nvdimm_bus_unlock(dev);
	return sprintf(buf, "%s\n", atomic_read(&nvdimm->busy)
			? "active" : "idle");
}
static DEVICE_ATTR_RO(state);

static ssize_t available_slots_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);
	ssize_t rc;
	u32 nfree;

	if (!ndd)
		return -ENXIO;

	nvdimm_bus_lock(dev);
	nfree = nd_label_nfree(ndd);
	if (nfree - 1 > nfree) {
		dev_WARN_ONCE(dev, 1, "we ate our last label?\n");
		nfree = 0;
	} else
		nfree--;
	rc = sprintf(buf, "%d\n", nfree);
	nvdimm_bus_unlock(dev);
	return rc;
}
static DEVICE_ATTR_RO(available_slots);

static struct attribute *nvdimm_attributes[] = {
	&dev_attr_state.attr,
	&dev_attr_commands.attr,
	&dev_attr_available_slots.attr,
	NULL,
};

struct attribute_group nvdimm_attribute_group = {
	.attrs = nvdimm_attributes,
};
EXPORT_SYMBOL_GPL(nvdimm_attribute_group);

struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
		const struct attribute_group **groups, unsigned long flags,
		unsigned long cmd_mask)
{
	struct nvdimm *nvdimm = kzalloc(sizeof(*nvdimm), GFP_KERNEL);
	struct device *dev;

	if (!nvdimm)
		return NULL;

	nvdimm->id = ida_simple_get(&dimm_ida, 0, 0, GFP_KERNEL);
	if (nvdimm->id < 0) {
		kfree(nvdimm);
		return NULL;
	}
	nvdimm->provider_data = provider_data;
	nvdimm->flags = flags;
	nvdimm->cmd_mask = cmd_mask;
	atomic_set(&nvdimm->busy, 0);
	dev = &nvdimm->dev;
	dev_set_name(dev, "nmem%d", nvdimm->id);
	dev->parent = &nvdimm_bus->dev;
	dev->type = &nvdimm_device_type;
	dev->devt = MKDEV(nvdimm_major, nvdimm->id);
	dev->groups = groups;
	nd_device_register(dev);

	return nvdimm;
}
EXPORT_SYMBOL_GPL(nvdimm_create);

/**
 * nd_blk_available_dpa - account the unused dpa of BLK region
 * @nd_mapping: container of dpa-resource-root + labels
 *
 * Unlike PMEM, BLK namespaces can occupy discontiguous DPA ranges.
 */
resource_size_t nd_blk_available_dpa(struct nd_mapping *nd_mapping)
{
	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
	resource_size_t map_end, busy = 0, available;
	struct resource *res;

	if (!ndd)
		return 0;

	map_end = nd_mapping->start + nd_mapping->size - 1;
	for_each_dpa_resource(ndd, res)
		if (res->start >= nd_mapping->start && res->start < map_end) {
			resource_size_t end = min(map_end, res->end);

			busy += end - res->start + 1;
		} else if (res->end >= nd_mapping->start
				&& res->end <= map_end) {
			busy += res->end - nd_mapping->start;
		} else if (nd_mapping->start > res->start
				&& nd_mapping->start < res->end) {
			/* total eclipse of the BLK region mapping */
			busy += nd_mapping->size;
		}

	available = map_end - nd_mapping->start + 1;
	if (busy < available)
		return available - busy;
	return 0;
}

/**
 * nd_pmem_available_dpa - for the given dimm+region account unallocated dpa
 * @nd_mapping: container of dpa-resource-root + labels
 * @nd_region: constrain available space check to this reference region
 * @overlap: calculate available space assuming this level of overlap
 *
 * Validate that a PMEM label, if present, aligns with the start of an
 * interleave set and truncate the available size at the lowest BLK
 * overlap point.
 *
 * The expectation is that this routine is called multiple times as it
 * probes for the largest BLK encroachment for any single member DIMM of
 * the interleave set.  Once that value is determined the PMEM-limit for
 * the set can be established.
 */
resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
		struct nd_mapping *nd_mapping, resource_size_t *overlap)
{
	resource_size_t map_start, map_end, busy = 0, available, blk_start;
	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
	struct resource *res;
	const char *reason;

	if (!ndd)
		return 0;

	map_start = nd_mapping->start;
	map_end = map_start + nd_mapping->size - 1;
	blk_start = max(map_start, map_end + 1 - *overlap);
	for_each_dpa_resource(ndd, res)
		if (res->start >= map_start && res->start < map_end) {
			if (strncmp(res->name, "blk", 3) == 0)
				blk_start = min(blk_start, res->start);
			else if (res->start != map_start) {
				reason = "misaligned to iset";
				goto err;
			} else {
				if (busy) {
					reason = "duplicate overlapping PMEM reservations?";
					goto err;
				}
				busy += resource_size(res);
				continue;
			}
		} else if (res->end >= map_start && res->end <= map_end) {
			if (strncmp(res->name, "blk", 3) == 0) {
				/*
				 * If a BLK allocation overlaps the start of
				 * PMEM the entire interleave set may now only
				 * be used for BLK.
				 */
				blk_start = map_start;
			} else {
				reason = "misaligned to iset";
				goto err;
			}
		} else if (map_start > res->start && map_start < res->end) {
			/* total eclipse of the mapping */
			busy += nd_mapping->size;
			blk_start = map_start;
		}

	*overlap = map_end + 1 - blk_start;
	available = blk_start - map_start;
	if (busy < available)
		return available - busy;
	return 0;

 err:
	/*
	 * Something is wrong, PMEM must align with the start of the
	 * interleave set, and there can only be one allocation per set.
	 */
	nd_dbg_dpa(nd_region, ndd, res, "%s\n", reason);
	return 0;
}

void nvdimm_free_dpa(struct nvdimm_drvdata *ndd, struct resource *res)
{
	WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));
	kfree(res->name);
	__release_region(&ndd->dpa, res->start, resource_size(res));
}

struct resource *nvdimm_allocate_dpa(struct nvdimm_drvdata *ndd,
		struct nd_label_id *label_id, resource_size_t start,
		resource_size_t n)
{
	char *name = kmemdup(label_id, sizeof(*label_id), GFP_KERNEL);
	struct resource *res;

	if (!name)
		return NULL;

	WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));
	res = __request_region(&ndd->dpa, start, n, name, 0);
	if (!res)
		kfree(name);
	return res;
}

/**
 * nvdimm_allocated_dpa - sum up the dpa currently allocated to this label_id
 * @nvdimm: container of dpa-resource-root + labels
 * @label_id: dpa resource name of the form {pmem|blk}-<human readable uuid>
 */
resource_size_t nvdimm_allocated_dpa(struct nvdimm_drvdata *ndd,
		struct nd_label_id *label_id)
{
	resource_size_t allocated = 0;
	struct resource *res;

	for_each_dpa_resource(ndd, res)
		if (strcmp(res->name, label_id->id) == 0)
			allocated += resource_size(res);

	return allocated;
}

static int count_dimms(struct device *dev, void *c)
{
	int *count = c;

	if (is_nvdimm(dev))
		(*count)++;
	return 0;
}

int nvdimm_bus_check_dimm_count(struct nvdimm_bus *nvdimm_bus, int dimm_count)
{
	int count = 0;
	/* Flush any possible dimm registration failures */
	nd_synchronize();

	device_for_each_child(&nvdimm_bus->dev, &count, count_dimms);
	dev_dbg(&nvdimm_bus->dev, "%s: count: %d\n", __func__, count);
	if (count != dimm_count)
		return -ENXIO;
	return 0;
}
EXPORT_SYMBOL_GPL(nvdimm_bus_check_dimm_count);

void __exit nvdimm_devs_exit(void)
{
	ida_destroy(&dimm_ida);
}