/*
 * 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.
 */
#include <linux/libnvdimm.h>
#include <linux/badblocks.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/device.h>
#include <linux/ctype.h>
#include <linux/ndctl.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "nd-core.h"
#include "nd.h"

LIST_HEAD(nvdimm_bus_list);
DEFINE_MUTEX(nvdimm_bus_list_mutex);

void nvdimm_bus_lock(struct device *dev)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

        if (!nvdimm_bus)
                return;
        mutex_lock(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(nvdimm_bus_lock);

void nvdimm_bus_unlock(struct device *dev)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

        if (!nvdimm_bus)
                return;
        mutex_unlock(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(nvdimm_bus_unlock);

bool is_nvdimm_bus_locked(struct device *dev)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

        if (!nvdimm_bus)
                return false;
        return mutex_is_locked(&nvdimm_bus->reconfig_mutex);
}
EXPORT_SYMBOL(is_nvdimm_bus_locked);

struct nvdimm_map {
        struct nvdimm_bus *nvdimm_bus;
        struct list_head list;
        resource_size_t offset;
        unsigned long flags;
        size_t size;
        union {
                void *mem;
                void __iomem *iomem;
        };
        struct kref kref;
};

static struct nvdimm_map *find_nvdimm_map(struct device *dev,
                resource_size_t offset)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
        struct nvdimm_map *nvdimm_map;

        list_for_each_entry(nvdimm_map, &nvdimm_bus->mapping_list, list)
                if (nvdimm_map->offset == offset)
                        return nvdimm_map;
        return NULL;
}

static struct nvdimm_map *alloc_nvdimm_map(struct device *dev,
                resource_size_t offset, size_t size, unsigned long flags)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
        struct nvdimm_map *nvdimm_map;

        nvdimm_map = kzalloc(sizeof(*nvdimm_map), GFP_KERNEL);
        if (!nvdimm_map)
                return NULL;

        INIT_LIST_HEAD(&nvdimm_map->list);
        nvdimm_map->nvdimm_bus = nvdimm_bus;
        nvdimm_map->offset = offset;
        nvdimm_map->flags = flags;
        nvdimm_map->size = size;
        kref_init(&nvdimm_map->kref);

        if (!request_mem_region(offset, size, dev_name(&nvdimm_bus->dev))) {
                dev_err(&nvdimm_bus->dev, "failed to request %pa + %zd for %s\n",
                                &offset, size, dev_name(dev));
                goto err_request_region;
        }

        if (flags)
                nvdimm_map->mem = memremap(offset, size, flags);
        else
                nvdimm_map->iomem = ioremap(offset, size);

        if (!nvdimm_map->mem)
                goto err_map;

        dev_WARN_ONCE(dev, !is_nvdimm_bus_locked(dev), "%s: bus unlocked!",
                        __func__);
        list_add(&nvdimm_map->list, &nvdimm_bus->mapping_list);

        return nvdimm_map;

 err_map:
        release_mem_region(offset, size);
 err_request_region:
        kfree(nvdimm_map);
        return NULL;
}

static void nvdimm_map_release(struct kref *kref)
{
        struct nvdimm_bus *nvdimm_bus;
        struct nvdimm_map *nvdimm_map;

        nvdimm_map = container_of(kref, struct nvdimm_map, kref);
        nvdimm_bus = nvdimm_map->nvdimm_bus;

        dev_dbg(&nvdimm_bus->dev, "%s: %pa\n", __func__, &nvdimm_map->offset);
        list_del(&nvdimm_map->list);
        if (nvdimm_map->flags)
                memunmap(nvdimm_map->mem);
        else
                iounmap(nvdimm_map->iomem);
        release_mem_region(nvdimm_map->offset, nvdimm_map->size);
        kfree(nvdimm_map);
}

static void nvdimm_map_put(void *data)
{
        struct nvdimm_map *nvdimm_map = data;
        struct nvdimm_bus *nvdimm_bus = nvdimm_map->nvdimm_bus;

        nvdimm_bus_lock(&nvdimm_bus->dev);
        kref_put(&nvdimm_map->kref, nvdimm_map_release);
        nvdimm_bus_unlock(&nvdimm_bus->dev);
}

/**
 * devm_nvdimm_memremap - map a resource that is shared across regions
 * @dev: device that will own a reference to the shared mapping
 * @offset: physical base address of the mapping
 * @size: mapping size
 * @flags: memremap flags, or, if zero, perform an ioremap instead
 */
void *devm_nvdimm_memremap(struct device *dev, resource_size_t offset,
                size_t size, unsigned long flags)
{
        struct nvdimm_map *nvdimm_map;

        nvdimm_bus_lock(dev);
        nvdimm_map = find_nvdimm_map(dev, offset);
        if (!nvdimm_map)
                nvdimm_map = alloc_nvdimm_map(dev, offset, size, flags);
        else
                kref_get(&nvdimm_map->kref);
        nvdimm_bus_unlock(dev);

        if (!nvdimm_map)
                return NULL;

        if (devm_add_action_or_reset(dev, nvdimm_map_put, nvdimm_map))
                return NULL;

        return nvdimm_map->mem;
}
EXPORT_SYMBOL_GPL(devm_nvdimm_memremap);

u64 nd_fletcher64(void *addr, size_t len, bool le)
{
        u32 *buf = addr;
        u32 lo32 = 0;
        u64 hi32 = 0;
        int i;

        for (i = 0; i < len / sizeof(u32); i++) {
                lo32 += le ? le32_to_cpu((__le32) buf[i]) : buf[i];
                hi32 += lo32;
        }

        return hi32 << 32 | lo32;
}
EXPORT_SYMBOL_GPL(nd_fletcher64);

struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
{
        /* struct nvdimm_bus definition is private to libnvdimm */
        return nvdimm_bus->nd_desc;
}
EXPORT_SYMBOL_GPL(to_nd_desc);

struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
{
        /* struct nvdimm_bus definition is private to libnvdimm */
        return &nvdimm_bus->dev;
}
EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);

static bool is_uuid_sep(char sep)
{
        if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
                return true;
        return false;
}

static int nd_uuid_parse(struct device *dev, u8 *uuid_out, const char *buf,
                size_t len)
{
        const char *str = buf;
        u8 uuid[16];
        int i;

        for (i = 0; i < 16; i++) {
                if (!isxdigit(str[0]) || !isxdigit(str[1])) {
                        dev_dbg(dev, "%s: pos: %d buf[%zd]: %c buf[%zd]: %c\n",
                                        __func__, i, str - buf, str[0],
                                        str + 1 - buf, str[1]);
                        return -EINVAL;
                }

                uuid[i] = (hex_to_bin(str[0]) << 4) | hex_to_bin(str[1]);
                str += 2;
                if (is_uuid_sep(*str))
                        str++;
        }

        memcpy(uuid_out, uuid, sizeof(uuid));
        return 0;
}

/**
 * nd_uuid_store: common implementation for writing 'uuid' sysfs attributes
 * @dev: container device for the uuid property
 * @uuid_out: uuid buffer to replace
 * @buf: raw sysfs buffer to parse
 *
 * Enforce that uuids can only be changed while the device is disabled
 * (driver detached)
 * LOCKING: expects device_lock() is held on entry
 */
int nd_uuid_store(struct device *dev, u8 **uuid_out, const char *buf,
                size_t len)
{
        u8 uuid[16];
        int rc;

        if (dev->driver)
                return -EBUSY;

        rc = nd_uuid_parse(dev, uuid, buf, len);
        if (rc)
                return rc;

        kfree(*uuid_out);
        *uuid_out = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
        if (!(*uuid_out))
                return -ENOMEM;

        return 0;
}

ssize_t nd_sector_size_show(unsigned long current_lbasize,
                const unsigned long *supported, char *buf)
{
        ssize_t len = 0;
        int i;

        for (i = 0; supported[i]; i++)
                if (current_lbasize == supported[i])
                        len += sprintf(buf + len, "[%ld] ", supported[i]);
                else
                        len += sprintf(buf + len, "%ld ", supported[i]);
        len += sprintf(buf + len, "\n");
        return len;
}

ssize_t nd_sector_size_store(struct device *dev, const char *buf,
                unsigned long *current_lbasize, const unsigned long *supported)
{
        unsigned long lbasize;
        int rc, i;

        if (dev->driver)
                return -EBUSY;

        rc = kstrtoul(buf, 0, &lbasize);
        if (rc)
                return rc;

        for (i = 0; supported[i]; i++)
                if (lbasize == supported[i])
                        break;

        if (supported[i]) {
                *current_lbasize = lbasize;
                return 0;
        } else {
                return -EINVAL;
        }
}

static ssize_t commands_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        int cmd, len = 0;
        struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
        struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;

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

static const char *nvdimm_bus_provider(struct nvdimm_bus *nvdimm_bus)
{
        struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
        struct device *parent = nvdimm_bus->dev.parent;

        if (nd_desc->provider_name)
                return nd_desc->provider_name;
        else if (parent)
                return dev_name(parent);
        else
                return "unknown";
}

static ssize_t provider_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);

        return sprintf(buf, "%s\n", nvdimm_bus_provider(nvdimm_bus));
}
static DEVICE_ATTR_RO(provider);

static int flush_namespaces(struct device *dev, void *data)
{
        device_lock(dev);
        device_unlock(dev);
        return 0;
}

static int flush_regions_dimms(struct device *dev, void *data)
{
        device_lock(dev);
        device_unlock(dev);
        device_for_each_child(dev, NULL, flush_namespaces);
        return 0;
}

static ssize_t wait_probe_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
        struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
        int rc;

        if (nd_desc->flush_probe) {
                rc = nd_desc->flush_probe(nd_desc);
                if (rc)
                        return rc;
        }
        nd_synchronize();
        device_for_each_child(dev, NULL, flush_regions_dimms);
        return sprintf(buf, "1\n");
}
static DEVICE_ATTR_RO(wait_probe);

static struct attribute *nvdimm_bus_attributes[] = {
        &dev_attr_commands.attr,
        &dev_attr_wait_probe.attr,
        &dev_attr_provider.attr,
        NULL,
};

struct attribute_group nvdimm_bus_attribute_group = {
        .attrs = nvdimm_bus_attributes,
};
EXPORT_SYMBOL_GPL(nvdimm_bus_attribute_group);

static void set_badblock(struct badblocks *bb, sector_t s, int num)
{
        dev_dbg(bb->dev, "Found a poison range (0x%llx, 0x%llx)\n",
                        (u64) s * 512, (u64) num * 512);
        /* this isn't an error as the hardware will still throw an exception */
        if (badblocks_set(bb, s, num, 1))
                dev_info_once(bb->dev, "%s: failed for sector %llx\n",
                                __func__, (u64) s);
}

/**
 * __add_badblock_range() - Convert a physical address range to bad sectors
 * @bb:         badblocks instance to populate
 * @ns_offset:  namespace offset where the error range begins (in bytes)
 * @len:        number of bytes of poison to be added
 *
 * This assumes that the range provided with (ns_offset, len) is within
 * the bounds of physical addresses for this namespace, i.e. lies in the
 * interval [ns_start, ns_start + ns_size)
 */
static void __add_badblock_range(struct badblocks *bb, u64 ns_offset, u64 len)
{
        const unsigned int sector_size = 512;
        sector_t start_sector;
        u64 num_sectors;
        u32 rem;

        start_sector = div_u64(ns_offset, sector_size);
        num_sectors = div_u64_rem(len, sector_size, &rem);
        if (rem)
                num_sectors++;

        if (unlikely(num_sectors > (u64)INT_MAX)) {
                u64 remaining = num_sectors;
                sector_t s = start_sector;

                while (remaining) {
                        int done = min_t(u64, remaining, INT_MAX);

                        set_badblock(bb, s, done);
                        remaining -= done;
                        s += done;
                }
        } else
                set_badblock(bb, start_sector, num_sectors);
}

static void badblocks_populate(struct list_head *poison_list,
                struct badblocks *bb, const struct resource *res)
{
        struct nd_poison *pl;

        if (list_empty(poison_list))
                return;

        list_for_each_entry(pl, poison_list, list) {
                u64 pl_end = pl->start + pl->length - 1;

                /* Discard intervals with no intersection */
                if (pl_end < res->start)
                        continue;
                if (pl->start >  res->end)
                        continue;
                /* Deal with any overlap after start of the namespace */
                if (pl->start >= res->start) {
                        u64 start = pl->start;
                        u64 len;

                        if (pl_end <= res->end)
                                len = pl->length;
                        else
                                len = res->start + resource_size(res)
                                        - pl->start;
                        __add_badblock_range(bb, start - res->start, len);
                        continue;
                }
                /* Deal with overlap for poison starting before the namespace */
                if (pl->start < res->start) {
                        u64 len;

                        if (pl_end < res->end)
                                len = pl->start + pl->length - res->start;
                        else
                                len = resource_size(res);
                        __add_badblock_range(bb, 0, len);
                }
        }
}

/**
 * nvdimm_badblocks_populate() - Convert a list of poison ranges to badblocks
 * @region: parent region of the range to interrogate
 * @bb: badblocks instance to populate
 * @res: resource range to consider
 *
 * The poison list generated during bus initialization may contain
 * multiple, possibly overlapping physical address ranges.  Compare each
 * of these ranges to the resource range currently being initialized,
 * and add badblocks entries for all matching sub-ranges
 */
void nvdimm_badblocks_populate(struct nd_region *nd_region,
                struct badblocks *bb, const struct resource *res)
{
        struct nvdimm_bus *nvdimm_bus;
        struct list_head *poison_list;

        if (!is_nd_pmem(&nd_region->dev)) {
                dev_WARN_ONCE(&nd_region->dev, 1,
                                "%s only valid for pmem regions\n", __func__);
                return;
        }
        nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
        poison_list = &nvdimm_bus->poison_list;

        nvdimm_bus_lock(&nvdimm_bus->dev);
        badblocks_populate(poison_list, bb, res);
        nvdimm_bus_unlock(&nvdimm_bus->dev);
}
EXPORT_SYMBOL_GPL(nvdimm_badblocks_populate);

static int add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length,
                        gfp_t flags)
{
        struct nd_poison *pl;

        pl = kzalloc(sizeof(*pl), flags);
        if (!pl)
                return -ENOMEM;

        pl->start = addr;
        pl->length = length;
        list_add_tail(&pl->list, &nvdimm_bus->poison_list);

        return 0;
}

static int bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
{
        struct nd_poison *pl;

        if (list_empty(&nvdimm_bus->poison_list))
                return add_poison(nvdimm_bus, addr, length, GFP_KERNEL);

        /*
         * There is a chance this is a duplicate, check for those first.
         * This will be the common case as ARS_STATUS returns all known
         * errors in the SPA space, and we can't query it per region
         */
        list_for_each_entry(pl, &nvdimm_bus->poison_list, list)
                if (pl->start == addr) {
                        /* If length has changed, update this list entry */
                        if (pl->length != length)
                                pl->length = length;
                        return 0;
                }

        /*
         * If not a duplicate or a simple length update, add the entry as is,
         * as any overlapping ranges will get resolved when the list is consumed
         * and converted to badblocks
         */
        return add_poison(nvdimm_bus, addr, length, GFP_KERNEL);
}

int nvdimm_bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
{
        int rc;

        nvdimm_bus_lock(&nvdimm_bus->dev);
        rc = bus_add_poison(nvdimm_bus, addr, length);
        nvdimm_bus_unlock(&nvdimm_bus->dev);

        return rc;
}
EXPORT_SYMBOL_GPL(nvdimm_bus_add_poison);

void nvdimm_clear_from_poison_list(struct nvdimm_bus *nvdimm_bus,
                phys_addr_t start, unsigned int len)
{
        struct list_head *poison_list = &nvdimm_bus->poison_list;
        u64 clr_end = start + len - 1;
        struct nd_poison *pl, *next;

        nvdimm_bus_lock(&nvdimm_bus->dev);
        WARN_ON_ONCE(list_empty(poison_list));

        /*
         * [start, clr_end] is the poison interval being cleared.
         * [pl->start, pl_end] is the poison_list entry we're comparing
         * the above interval against. The poison list entry may need
         * to be modified (update either start or length), deleted, or
         * split into two based on the overlap characteristics
         */

        list_for_each_entry_safe(pl, next, poison_list, list) {
                u64 pl_end = pl->start + pl->length - 1;

                /* Skip intervals with no intersection */
                if (pl_end < start)
                        continue;
                if (pl->start >  clr_end)
                        continue;
                /* Delete completely overlapped poison entries */
                if ((pl->start >= start) && (pl_end <= clr_end)) {
                        list_del(&pl->list);
                        kfree(pl);
                        continue;
                }
                /* Adjust start point of partially cleared entries */
                if ((start <= pl->start) && (clr_end > pl->start)) {
                        pl->length -= clr_end - pl->start + 1;
                        pl->start = clr_end + 1;
                        continue;
                }
                /* Adjust pl->length for partial clearing at the tail end */
                if ((pl->start < start) && (pl_end <= clr_end)) {
                        /* pl->start remains the same */
                        pl->length = start - pl->start;
                        continue;
                }
                /*
                 * If clearing in the middle of an entry, we split it into
                 * two by modifying the current entry to represent one half of
                 * the split, and adding a new entry for the second half.
                 */
                if ((pl->start < start) && (pl_end > clr_end)) {
                        u64 new_start = clr_end + 1;
                        u64 new_len = pl_end - new_start + 1;

                        /* Add new entry covering the right half */
                        add_poison(nvdimm_bus, new_start, new_len, GFP_NOIO);
                        /* Adjust this entry to cover the left half */
                        pl->length = start - pl->start;
                        continue;
                }
        }
        nvdimm_bus_unlock(&nvdimm_bus->dev);
}
EXPORT_SYMBOL_GPL(nvdimm_clear_from_poison_list);

#ifdef CONFIG_BLK_DEV_INTEGRITY
static void nd_pi_nop_generate(struct blk_integrity_exchg *bix)
{
        return;
}
static int nd_pi_nop_verify(struct blk_integrity_exchg *bix)
{
        return 0;
}

int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
{
        struct blk_integrity integrity = {
                .name = "ND-PI-NOP",
                .generate_fn = nd_pi_nop_generate,
                .verify_fn = nd_pi_nop_verify,
                .tuple_size = meta_size,
                .tag_size = meta_size,
        };
        int ret;

        if (meta_size == 0)
                return 0;

        ret = blk_integrity_register(disk, &integrity);
        if (ret)
                return ret;

        blk_queue_max_integrity_segments(disk->queue, 1);

        return 0;
}
EXPORT_SYMBOL(nd_integrity_init);

#else /* CONFIG_BLK_DEV_INTEGRITY */
int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)
{
        return 0;
}
EXPORT_SYMBOL(nd_integrity_init);

#endif

static __init int libnvdimm_init(void)
{
        int rc;

        rc = nvdimm_bus_init();
        if (rc)
                return rc;
        rc = nvdimm_init();
        if (rc)
                goto err_dimm;
        rc = nd_region_init();
        if (rc)
                goto err_region;
        return 0;
 err_region:
        nvdimm_exit();
 err_dimm:
        nvdimm_bus_exit();
        return rc;
}

static __exit void libnvdimm_exit(void)
{
        WARN_ON(!list_empty(&nvdimm_bus_list));
        nd_region_exit();
        nvdimm_exit();
        nvdimm_bus_exit();
        nd_region_devs_exit();
        nvdimm_devs_exit();
}

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
subsys_initcall(libnvdimm_init);
module_exit(libnvdimm_exit);