/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2012-2013 Intel Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/disk.h>
#include <sys/fcntl.h>
#include <sys/ioccom.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/systm.h>

#include <dev/pci/pcivar.h>

#include <geom/geom.h>

#include "nvme_private.h"
#include "nvme_linux.h"

static void             nvme_bio_child_inbed(struct bio *parent, int abio_error);
static void             nvme_bio_child_done(void *arg,
                                            const struct nvme_completion *cpl);
static uint32_t         nvme_get_num_segments(uint64_t addr, uint64_t size,
                                              uint32_t alignment);
static void             nvme_free_child_bios(int num_bios,
                                             struct bio **child_bios);
static struct bio **    nvme_allocate_child_bios(int num_bios);
static struct bio **    nvme_construct_child_bios(struct bio *bp,
                                                  uint32_t alignment,
                                                  int *num_bios);
static int              nvme_ns_split_bio(struct nvme_namespace *ns,
                                          struct bio *bp,
                                          uint32_t alignment);

static int
nvme_ns_ioctl(struct cdev *cdev, u_long cmd, caddr_t arg, int flag,
    struct thread *td)
{
        struct nvme_namespace                   *ns;
        struct nvme_controller                  *ctrlr;
        struct nvme_pt_command                  *pt;

        ns = cdev->si_drv1;
        ctrlr = ns->ctrlr;

        switch (cmd) {
        case NVME_IO_TEST:
        case NVME_BIO_TEST:
                nvme_ns_test(ns, cmd, arg);
                break;
        case NVME_PASSTHROUGH_CMD:
                pt = (struct nvme_pt_command *)arg;
                return (nvme_ctrlr_passthrough_cmd(ctrlr, pt, ns->id,
                    1 /* is_user_buffer */, 0 /* is_admin_cmd */));
        case NVME_GET_NSID:
        {
                struct nvme_get_nsid *gnsid = (struct nvme_get_nsid *)arg;
                strlcpy(gnsid->cdev, device_get_nameunit(ctrlr->dev),
                    sizeof(gnsid->cdev));
                gnsid->nsid = ns->id;
                break;
        }
        case DIOCGIDENT: {
                uint8_t *sn = arg;
                nvme_cdata_get_disk_ident(&ctrlr->cdata, sn);
                break;
        }
        case DIOCGMEDIASIZE:
                *(off_t *)arg = (off_t)nvme_ns_get_size(ns);
                break;
        case DIOCGSECTORSIZE:
                *(u_int *)arg = nvme_ns_get_sector_size(ns);
                break;
        /* Linux Compatible (see nvme_linux.h) */
        case NVME_IOCTL_ID:
                td->td_retval[0] = ns->id;
                return (0);

        case NVME_IOCTL_ADMIN_CMD:
        case NVME_IOCTL_IO_CMD: {
                struct nvme_passthru_cmd *npc = (struct nvme_passthru_cmd *)arg;

                return (nvme_ctrlr_linux_passthru_cmd(ctrlr, npc, ns->id, true,
                    cmd == NVME_IOCTL_ADMIN_CMD));
        }
        default:
                return (ENOTTY);
        }

        return (0);
}

static int
nvme_ns_open(struct cdev *dev __unused, int flags, int fmt __unused,
    struct thread *td)
{
        int error = 0;

        if (flags & FWRITE)
                error = securelevel_gt(td->td_ucred, 0);

        return (error);
}

static int
nvme_ns_close(struct cdev *dev __unused, int flags, int fmt __unused,
    struct thread *td)
{
        return (0);
}

static void
nvme_ns_strategy_done(void *arg, const struct nvme_completion *cpl)
{
        struct bio *bp = arg;

        if (nvme_completion_is_error(cpl)) {
                bp->bio_error = EIO;
                bp->bio_flags |= BIO_ERROR;
                bp->bio_resid = bp->bio_bcount;
        } else
                bp->bio_resid = 0;

        biodone(bp);
}

static void
nvme_ns_strategy(struct bio *bp)
{
        struct nvme_namespace   *ns;
        int                     err;

        ns = bp->bio_dev->si_drv1;
        err = nvme_ns_bio_process(ns, bp, nvme_ns_strategy_done);

        if (err) {
                bp->bio_error = err;
                bp->bio_flags |= BIO_ERROR;
                bp->bio_resid = bp->bio_bcount;
                biodone(bp);
        }

}

static struct cdevsw nvme_ns_cdevsw = {
        .d_version =    D_VERSION,
        .d_flags =      D_DISK,
        .d_read =       physread,
        .d_write =      physwrite,
        .d_open =       nvme_ns_open,
        .d_close =      nvme_ns_close,
        .d_strategy =   nvme_ns_strategy,
        .d_ioctl =      nvme_ns_ioctl
};

uint32_t
nvme_ns_get_max_io_xfer_size(struct nvme_namespace *ns)
{
        return ns->ctrlr->max_xfer_size;
}

uint32_t
nvme_ns_get_sector_size(struct nvme_namespace *ns)
{
        uint8_t flbas_fmt, lbads;

        flbas_fmt = NVMEV(NVME_NS_DATA_FLBAS_FORMAT, ns->data.flbas);
        lbads = NVMEV(NVME_NS_DATA_LBAF_LBADS, ns->data.lbaf[flbas_fmt]);

        return (1 << lbads);
}

uint64_t
nvme_ns_get_num_sectors(struct nvme_namespace *ns)
{
        return (ns->data.nsze);
}

uint64_t
nvme_ns_get_size(struct nvme_namespace *ns)
{
        return (nvme_ns_get_num_sectors(ns) * nvme_ns_get_sector_size(ns));
}

uint32_t
nvme_ns_get_flags(struct nvme_namespace *ns)
{
        return (ns->flags);
}

const char *
nvme_ns_get_serial_number(struct nvme_namespace *ns)
{
        return ((const char *)ns->ctrlr->cdata.sn);
}

const char *
nvme_ns_get_model_number(struct nvme_namespace *ns)
{
        return ((const char *)ns->ctrlr->cdata.mn);
}

const struct nvme_namespace_data *
nvme_ns_get_data(struct nvme_namespace *ns)
{
        return (&ns->data);
}

uint32_t
nvme_ns_get_stripesize(struct nvme_namespace *ns)
{
        uint32_t ss;

        if (NVMEV(NVME_NS_DATA_NSFEAT_NPVALID, ns->data.nsfeat) != 0) {
                ss = nvme_ns_get_sector_size(ns);
                if (ns->data.npwa != 0)
                        return ((ns->data.npwa + 1) * ss);
                else if (ns->data.npwg != 0)
                        return ((ns->data.npwg + 1) * ss);
        }
        return (ns->boundary);
}

static void
nvme_ns_bio_done(void *arg, const struct nvme_completion *status)
{
        struct bio      *bp = arg;
        nvme_cb_fn_t    bp_cb_fn;

        bp_cb_fn = bp->bio_driver1;

        if (bp->bio_driver2)
                free(bp->bio_driver2, M_NVME);

        if (nvme_completion_is_error(status)) {
                bp->bio_flags |= BIO_ERROR;
                if (bp->bio_error == 0)
                        bp->bio_error = EIO;
        }

        if ((bp->bio_flags & BIO_ERROR) == 0)
                bp->bio_resid = 0;
        else
                bp->bio_resid = bp->bio_bcount;

        bp_cb_fn(bp, status);
}

static void
nvme_bio_child_inbed(struct bio *parent, int abio_error)
{
        struct nvme_completion  parent_cpl;
        int                     children, inbed;

        if (abio_error != 0) {
                parent->bio_flags |= BIO_ERROR;
                parent->bio_error = abio_error;
        }

        /*
         * atomic_fetchadd will return value before adding 1, so we still
         *  must add 1 to get the updated inbed number.  Save bio_children
         *  before incrementing to guard against race conditions when
         *  two children bios complete on different queues.
         */
        children = atomic_load_acq_int(&parent->bio_children);
        inbed = atomic_fetchadd_int(&parent->bio_inbed, 1) + 1;
        if (inbed == children) {
                bzero(&parent_cpl, sizeof(parent_cpl));
                if (parent->bio_flags & BIO_ERROR) {
                        parent_cpl.status &= ~NVMEM(NVME_STATUS_SC);
                        parent_cpl.status |= NVMEF(NVME_STATUS_SC,
                            NVME_SC_DATA_TRANSFER_ERROR);
                }
                nvme_ns_bio_done(parent, &parent_cpl);
        }
}

static void
nvme_bio_child_done(void *arg, const struct nvme_completion *cpl)
{
        struct bio              *child = arg;
        struct bio              *parent;
        int                     abio_error;

        parent = child->bio_parent;
        g_destroy_bio(child);
        abio_error = nvme_completion_is_error(cpl) ? EIO : 0;
        nvme_bio_child_inbed(parent, abio_error);
}

static uint32_t
nvme_get_num_segments(uint64_t addr, uint64_t size, uint32_t align)
{
        uint32_t        num_segs, offset, remainder;

        if (align == 0)
                return (1);

        KASSERT((align & (align - 1)) == 0, ("alignment not power of 2\n"));

        num_segs = size / align;
        remainder = size & (align - 1);
        offset = addr & (align - 1);
        if (remainder > 0 || offset > 0)
                num_segs += 1 + (remainder + offset - 1) / align;
        return (num_segs);
}

static void
nvme_free_child_bios(int num_bios, struct bio **child_bios)
{
        int i;

        for (i = 0; i < num_bios; i++) {
                if (child_bios[i] != NULL)
                        g_destroy_bio(child_bios[i]);
        }

        free(child_bios, M_NVME);
}

static struct bio **
nvme_allocate_child_bios(int num_bios)
{
        struct bio **child_bios;
        int err = 0, i;

        child_bios = malloc(num_bios * sizeof(struct bio *), M_NVME, M_NOWAIT);
        if (child_bios == NULL)
                return (NULL);

        for (i = 0; i < num_bios; i++) {
                child_bios[i] = g_new_bio();
                if (child_bios[i] == NULL)
                        err = ENOMEM;
        }

        if (err == ENOMEM) {
                nvme_free_child_bios(num_bios, child_bios);
                return (NULL);
        }

        return (child_bios);
}

static struct bio **
nvme_construct_child_bios(struct bio *bp, uint32_t alignment, int *num_bios)
{
        struct bio      **child_bios;
        struct bio      *child;
        uint64_t        cur_offset;
        caddr_t         data;
        uint32_t        rem_bcount;
        int             i;
        struct vm_page  **ma;
        uint32_t        ma_offset;

        *num_bios = nvme_get_num_segments(bp->bio_offset, bp->bio_bcount,
            alignment);
        child_bios = nvme_allocate_child_bios(*num_bios);
        if (child_bios == NULL)
                return (NULL);

        bp->bio_children = *num_bios;
        bp->bio_inbed = 0;
        cur_offset = bp->bio_offset;
        rem_bcount = bp->bio_bcount;
        data = bp->bio_data;
        ma_offset = bp->bio_ma_offset;
        ma = bp->bio_ma;

        for (i = 0; i < *num_bios; i++) {
                child = child_bios[i];
                child->bio_parent = bp;
                child->bio_cmd = bp->bio_cmd;
                child->bio_offset = cur_offset;
                child->bio_bcount = min(rem_bcount,
                    alignment - (cur_offset & (alignment - 1)));
                child->bio_flags = bp->bio_flags;
                if (bp->bio_flags & BIO_UNMAPPED) {
                        child->bio_ma_offset = ma_offset;
                        child->bio_ma = ma;
                        child->bio_ma_n =
                            nvme_get_num_segments(child->bio_ma_offset,
                                child->bio_bcount, PAGE_SIZE);
                        ma_offset = (ma_offset + child->bio_bcount) &
                            PAGE_MASK;
                        ma += child->bio_ma_n;
                        if (ma_offset != 0)
                                ma -= 1;
                } else {
                        child->bio_data = data;
                        data += child->bio_bcount;
                }
                cur_offset += child->bio_bcount;
                rem_bcount -= child->bio_bcount;
        }

        return (child_bios);
}

static int
nvme_ns_split_bio(struct nvme_namespace *ns, struct bio *bp,
    uint32_t alignment)
{
        struct bio      *child;
        struct bio      **child_bios;
        int             err, i, num_bios;

        child_bios = nvme_construct_child_bios(bp, alignment, &num_bios);
        if (child_bios == NULL)
                return (ENOMEM);

        counter_u64_add(ns->ctrlr->alignment_splits, 1);
        for (i = 0; i < num_bios; i++) {
                child = child_bios[i];
                err = nvme_ns_bio_process(ns, child, nvme_bio_child_done);
                if (err != 0) {
                        nvme_bio_child_inbed(bp, err);
                        g_destroy_bio(child);
                }
        }

        free(child_bios, M_NVME);
        return (0);
}

int
nvme_ns_bio_process(struct nvme_namespace *ns, struct bio *bp,
        nvme_cb_fn_t cb_fn)
{
        struct nvme_dsm_range   *dsm_range;
        uint32_t                num_bios;
        int                     err;

        bp->bio_driver1 = cb_fn;

        if (ns->boundary > 0 &&
            (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
                num_bios = nvme_get_num_segments(bp->bio_offset,
                    bp->bio_bcount, ns->boundary);
                if (num_bios > 1)
                        return (nvme_ns_split_bio(ns, bp, ns->boundary));
        }

        switch (bp->bio_cmd) {
        case BIO_READ:
                err = nvme_ns_cmd_read_bio(ns, bp, nvme_ns_bio_done, bp);
                break;
        case BIO_WRITE:
                err = nvme_ns_cmd_write_bio(ns, bp, nvme_ns_bio_done, bp);
                break;
        case BIO_FLUSH:
                err = nvme_ns_cmd_flush(ns, nvme_ns_bio_done, bp);
                break;
        case BIO_DELETE:
                dsm_range =
                    malloc(sizeof(struct nvme_dsm_range), M_NVME,
                    M_ZERO | M_NOWAIT);
                if (!dsm_range) {
                        err = ENOMEM;
                        break;
                }
                dsm_range->length =
                    htole32(bp->bio_bcount/nvme_ns_get_sector_size(ns));
                dsm_range->starting_lba =
                    htole64(bp->bio_offset/nvme_ns_get_sector_size(ns));
                bp->bio_driver2 = dsm_range;
                err = nvme_ns_cmd_deallocate(ns, dsm_range, 1,
                        nvme_ns_bio_done, bp);
                if (err != 0)
                        free(dsm_range, M_NVME);
                break;
        default:
                err = EOPNOTSUPP;
                break;
        }

        return (err);
}

int
nvme_ns_ioctl_process(struct nvme_namespace *ns, u_long cmd, caddr_t arg,
    int flag, struct thread *td)
{
        return (nvme_ns_ioctl(ns->cdev, cmd, arg, flag, td));
}

int
nvme_ns_construct(struct nvme_namespace *ns, uint32_t id,
    struct nvme_controller *ctrlr)
{
        struct make_dev_args                    md_args;
        struct nvme_completion_poll_status      status;
        int                                     res;
        int                                     unit;
        uint8_t                                 flbas_fmt;
        uint8_t                                 vwc_present;

        ns->ctrlr = ctrlr;
        ns->id = id;

        /*
         * Namespaces are reconstructed after a controller reset, so check
         *  to make sure we only call mtx_init once on each mtx.
         *
         * TODO: Move this somewhere where it gets called at controller
         *  construction time, which is not invoked as part of each
         *  controller reset.
         */
        if (!mtx_initialized(&ns->lock))
                mtx_init(&ns->lock, "nvme ns lock", NULL, MTX_DEF);

        status.done = 0;
        nvme_ctrlr_cmd_identify_namespace(ctrlr, id, &ns->data,
            nvme_completion_poll_cb, &status);
        nvme_completion_poll(&status);
        if (nvme_completion_is_error(&status.cpl)) {
                nvme_printf(ctrlr, "nvme_identify_namespace failed\n");
                return (ENXIO);
        }

        /* Convert data to host endian */
        nvme_namespace_data_swapbytes(&ns->data);

        /*
         * If the size of is zero, chances are this isn't a valid
         * namespace (eg one that's not been configured yet). The
         * standard says the entire id will be zeros, so this is a
         * cheap way to test for that.
         */
        if (ns->data.nsze == 0) {
                ns->flags |= NVME_NS_GONE;
                return ((ns->flags & NVME_NS_ALIVE) ? 0 : ENXIO);
        }

        /*
         * Check the validity of the format specified. Note: format is a 0-based
         * value, so > is appropriate here, not >=.
         */
        flbas_fmt = NVMEV(NVME_NS_DATA_FLBAS_FORMAT, ns->data.flbas);
        if (flbas_fmt > ns->data.nlbaf) {
                nvme_printf(ctrlr, "nsid %d lba format %d invalid (> %d)\n",
                    id, flbas_fmt, ns->data.nlbaf + 1);
                return (ENXIO);
        }

        /*
         * Older Intel devices (like the PC35xxx and P45xx series) advertise in
         * vendor specific space an alignment that improves performance.  If
         * present use for the stripe size.  NVMe 1.3 standardized this as
         * NOIOB, and newer Intel drives use that.
         */
        if ((ctrlr->quirks & QUIRK_INTEL_ALIGNMENT) != 0) {
                if (ctrlr->cdata.vs[3] != 0)
                        ns->boundary =
                            1 << (ctrlr->cdata.vs[3] + NVME_MPS_SHIFT +
                                NVME_CAP_HI_MPSMIN(ctrlr->cap_hi));
                else
                        ns->boundary = 0;
        } else {
                ns->boundary = ns->data.noiob * nvme_ns_get_sector_size(ns);
        }

        if (nvme_ctrlr_has_dataset_mgmt(&ctrlr->cdata))
                ns->flags |= NVME_NS_DEALLOCATE_SUPPORTED;

        vwc_present = NVMEV(NVME_CTRLR_DATA_VWC_PRESENT, ctrlr->cdata.vwc);
        if (vwc_present)
                ns->flags |= NVME_NS_FLUSH_SUPPORTED;

        /*
         * cdev may have already been created, if we are reconstructing the
         *  namespace after a controller-level reset.
         */
        if (ns->cdev != NULL)
                return (0);

        /*
         * Namespace IDs start at 1, so we need to subtract 1 to create a
         *  correct unit number.
         */
        unit = device_get_unit(ctrlr->dev) * NVME_MAX_NAMESPACES + ns->id - 1;

        make_dev_args_init(&md_args);
        md_args.mda_devsw = &nvme_ns_cdevsw;
        md_args.mda_unit = unit;
        md_args.mda_mode = 0600;
        md_args.mda_si_drv1 = ns;
        res = make_dev_s(&md_args, &ns->cdev, "%sn%d",
            device_get_nameunit(ctrlr->dev), ns->id);
        if (res != 0)
                return (ENXIO);
        ns->cdev->si_drv2 = make_dev_alias(ns->cdev, "%sns%d",
            device_get_nameunit(ctrlr->dev), ns->id);
        ns->cdev->si_flags |= SI_UNMAPPED;
        ns->flags |= NVME_NS_ALIVE;

        return (0);
}

void
nvme_ns_destruct(struct nvme_namespace *ns)
{
        if (ns->cdev != NULL) {
                if (ns->cdev->si_drv2 != NULL)
                        destroy_dev(ns->cdev->si_drv2);
                destroy_dev(ns->cdev);
        }
}