/*
 * 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
 */
int nvdimm_check_config_data(struct device *dev)
{
        struct nvdimm *nvdimm = to_nvdimm(dev);

        if (!nvdimm->cmd_mask ||
            !test_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm->cmd_mask)) {
                if (nvdimm->flags & NDD_ALIASING)
                        return -ENXIO;
                else
                        return -ENOTTY;
        }

        return 0;
}

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

        if (!ndd)
                return -EINVAL;

        rc = nvdimm_check_config_data(ndd->dev);
        if (rc)
                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);

struct kobject *nvdimm_kobj(struct nvdimm *nvdimm)
{
        return &nvdimm->dev.kobj;
}
EXPORT_SYMBOL_GPL(nvdimm_kobj);

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, int num_flush,
                struct resource *flush_wpq)
{
        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;
        nvdimm->num_flush = num_flush;
        nvdimm->flush_wpq = flush_wpq;
        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);

int alias_dpa_busy(struct device *dev, void *data)
{
        resource_size_t map_end, blk_start, new, busy;
        struct blk_alloc_info *info = data;
        struct nd_mapping *nd_mapping;
        struct nd_region *nd_region;
        struct nvdimm_drvdata *ndd;
        struct resource *res;
        int i;

        if (!is_nd_pmem(dev))
                return 0;

        nd_region = to_nd_region(dev);
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                nd_mapping  = &nd_region->mapping[i];
                if (nd_mapping->nvdimm == info->nd_mapping->nvdimm)
                        break;
        }

        if (i >= nd_region->ndr_mappings)
                return 0;

        ndd = to_ndd(nd_mapping);
        map_end = nd_mapping->start + nd_mapping->size - 1;
        blk_start = nd_mapping->start;

        /*
         * In the allocation case ->res is set to free space that we are
         * looking to validate against PMEM aliasing collision rules
         * (i.e. BLK is allocated after all aliased PMEM).
         */
        if (info->res) {
                if (info->res->start >= nd_mapping->start
                                && info->res->start < map_end)
                        /* pass */;
                else
                        return 0;
        }

 retry:
        /*
         * Find the free dpa from the end of the last pmem allocation to
         * the end of the interleave-set mapping that is not already
         * covered by a blk allocation.
         */
        busy = 0;
        for_each_dpa_resource(ndd, res) {
                if ((res->start >= blk_start && res->start < map_end)
                                || (res->end >= blk_start
                                        && res->end <= map_end)) {
                        if (strncmp(res->name, "pmem", 4) == 0) {
                                new = max(blk_start, min(map_end + 1,
                                                        res->end + 1));
                                if (new != blk_start) {
                                        blk_start = new;
                                        goto retry;
                                }
                        } else
                                busy += min(map_end, res->end)
                                        - max(nd_mapping->start, res->start) + 1;
                } else if (nd_mapping->start > res->start
                                && map_end < res->end) {
                        /* total eclipse of the PMEM region mapping */
                        busy += nd_mapping->size;
                        break;
                }
        }

        /* update the free space range with the probed blk_start */
        if (info->res && blk_start > info->res->start) {
                info->res->start = max(info->res->start, blk_start);
                if (info->res->start > info->res->end)
                        info->res->end = info->res->start - 1;
                return 1;
        }

        info->available -= blk_start - nd_mapping->start + busy;

        return 0;
}

static int blk_dpa_busy(struct device *dev, void *data)
{
        struct blk_alloc_info *info = data;
        struct nd_mapping *nd_mapping;
        struct nd_region *nd_region;
        resource_size_t map_end;
        int i;

        if (!is_nd_pmem(dev))
                return 0;

        nd_region = to_nd_region(dev);
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                nd_mapping  = &nd_region->mapping[i];
                if (nd_mapping->nvdimm == info->nd_mapping->nvdimm)
                        break;
        }

        if (i >= nd_region->ndr_mappings)
                return 0;

        map_end = nd_mapping->start + nd_mapping->size - 1;
        if (info->res->start >= nd_mapping->start
                        && info->res->start < map_end) {
                if (info->res->end <= map_end) {
                        info->busy = 0;
                        return 1;
                } else {
                        info->busy -= info->res->end - map_end;
                        return 0;
                }
        } else if (info->res->end >= nd_mapping->start
                        && info->res->end <= map_end) {
                info->busy -= nd_mapping->start - info->res->start;
                return 0;
        } else {
                info->busy -= nd_mapping->size;
                return 0;
        }
}

/**
 * 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, but
 * we arrange for them to never start at an lower dpa than the last
 * PMEM allocation in an aliased region.
 */
resource_size_t nd_blk_available_dpa(struct nd_region *nd_region)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct blk_alloc_info info = {
                .nd_mapping = nd_mapping,
                .available = nd_mapping->size,
                .res = NULL,
        };
        struct resource *res;

        if (!ndd)
                return 0;

        device_for_each_child(&nvdimm_bus->dev, &info, alias_dpa_busy);

        /* now account for busy blk allocations in unaliased dpa */
        for_each_dpa_resource(ndd, res) {
                if (strncmp(res->name, "blk", 3) != 0)
                        continue;

                info.res = res;
                info.busy = resource_size(res);
                device_for_each_child(&nvdimm_bus->dev, &info, blk_dpa_busy);
                info.available -= info.busy;
        }

        return info.available;
}

/**
 * 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,
                                                max(map_start, res->start));
                        else if (res->end > map_end) {
                                reason = "misaligned to iset";
                                goto err;
                        } else
                                busy += resource_size(res);
                } 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
                                busy += resource_size(res);
                } 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:
        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);
}