/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2012-2016 Intel Corporation
 * All rights reserved.
 * Copyright (C) 2018-2020 Alexander Motin <mav@FreeBSD.org>
 *
 * 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/devicestat.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/taskqueue.h>
#include <machine/atomic.h>

#include <geom/geom.h>
#include <geom/geom_disk.h>

#include <dev/nvme/nvme.h>
#include <dev/nvme/nvme_private.h>

#include <dev/pci/pcivar.h>

#include "nvme_if.h"

#define NVD_STR         "nvd"

struct nvd_disk;
struct nvd_controller;

static disk_ioctl_t nvd_ioctl;
static disk_strategy_t nvd_strategy;
static dumper_t nvd_dump;
static disk_getattr_t nvd_getattr;

static void nvd_done(void *arg, const struct nvme_completion *cpl);
static void nvd_gone(struct nvd_disk *ndisk);

static int nvd_load(void);
static void nvd_unload(void);

MALLOC_DEFINE(M_NVD, "nvd", "nvd(4) allocations");

struct nvme_consumer *consumer_handle;

struct nvd_disk {
        struct nvd_controller   *ctrlr;

        struct bio_queue_head   bioq;
        struct task             bioqtask;
        struct mtx              bioqlock;

        struct disk             *disk;
        struct taskqueue        *tq;
        struct nvme_namespace   *ns;

        uint32_t                cur_depth;
#define NVD_ODEPTH      (1 << 30)
        uint32_t                ordered_in_flight;
        u_int                   unit;

        TAILQ_ENTRY(nvd_disk)   global_tailq;
        TAILQ_ENTRY(nvd_disk)   ctrlr_tailq;
};

struct nvd_controller {
        struct nvme_controller          *ctrlr;
        TAILQ_ENTRY(nvd_controller)     tailq;
        TAILQ_HEAD(, nvd_disk)          disk_head;
};

static struct mtx                       nvd_lock;
static TAILQ_HEAD(, nvd_controller)     ctrlr_head;
static TAILQ_HEAD(disk_list, nvd_disk)  disk_head;

static SYSCTL_NODE(_hw, OID_AUTO, nvd, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
    "nvd driver parameters");
/*
 * The NVMe specification does not define a maximum or optimal delete size, so
 *  technically max delete size is min(full size of the namespace, 2^32 - 1
 *  LBAs).  A single delete for a multi-TB NVMe namespace though may take much
 *  longer to complete than the nvme(4) I/O timeout period.  So choose a sensible
 *  default here that is still suitably large to minimize the number of overall
 *  delete operations.
 */
static uint64_t nvd_delete_max = (1024 * 1024 * 1024);  /* 1GB */
SYSCTL_UQUAD(_hw_nvd, OID_AUTO, delete_max, CTLFLAG_RDTUN, &nvd_delete_max, 0,
             "nvd maximum BIO_DELETE size in bytes");

static int nvd_modevent(module_t mod, int type, void *arg)
{
        int error = 0;

        switch (type) {
        case MOD_LOAD:
                error = nvd_load();
                break;
        case MOD_UNLOAD:
                nvd_unload();
                break;
        default:
                break;
        }

        return (error);
}

moduledata_t nvd_mod = {
        NVD_STR,
        (modeventhand_t)nvd_modevent,
        0
};

DECLARE_MODULE(nvd, nvd_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
MODULE_VERSION(nvd, 1);
MODULE_DEPEND(nvd, nvme, 1, 1, 1);

static int
nvd_load(void)
{
        if (!nvme_use_nvd)
                return (0);

        mtx_init(&nvd_lock, "nvd_lock", NULL, MTX_DEF);
        TAILQ_INIT(&ctrlr_head);
        TAILQ_INIT(&disk_head);
        return (0);
}

static void
nvd_unload(void)
{
        struct nvd_controller   *ctrlr;
        struct nvd_disk         *ndisk;

        if (!nvme_use_nvd)
                return;

        mtx_lock(&nvd_lock);
        while ((ctrlr = TAILQ_FIRST(&ctrlr_head)) != NULL) {
                TAILQ_REMOVE(&ctrlr_head, ctrlr, tailq);
                TAILQ_FOREACH(ndisk, &ctrlr->disk_head, ctrlr_tailq)
                        nvd_gone(ndisk);
                while (!TAILQ_EMPTY(&ctrlr->disk_head))
                        msleep(&ctrlr->disk_head, &nvd_lock, 0, "nvd_unload",0);
                free(ctrlr, M_NVD);
        }
        mtx_unlock(&nvd_lock);

        mtx_destroy(&nvd_lock);
}

static void
nvd_bio_submit(struct nvd_disk *ndisk, struct bio *bp)
{
        int err;

        bp->bio_driver1 = NULL;
        if (__predict_false(bp->bio_flags & BIO_ORDERED))
                atomic_add_int(&ndisk->cur_depth, NVD_ODEPTH);
        else
                atomic_add_int(&ndisk->cur_depth, 1);
        err = nvme_ns_bio_process(ndisk->ns, bp, nvd_done);
        if (err) {
                if (__predict_false(bp->bio_flags & BIO_ORDERED)) {
                        atomic_add_int(&ndisk->cur_depth, -NVD_ODEPTH);
                        atomic_add_int(&ndisk->ordered_in_flight, -1);
                        wakeup(&ndisk->cur_depth);
                } else {
                        if (atomic_fetchadd_int(&ndisk->cur_depth, -1) == 1 &&
                            __predict_false(ndisk->ordered_in_flight != 0))
                                wakeup(&ndisk->cur_depth);
                }
                bp->bio_error = err;
                bp->bio_flags |= BIO_ERROR;
                bp->bio_resid = bp->bio_bcount;
                biodone(bp);
        }
}

static void
nvd_strategy(struct bio *bp)
{
        struct nvd_disk *ndisk = (struct nvd_disk *)bp->bio_disk->d_drv1;

        /*
         * bio with BIO_ORDERED flag must be executed after all previous
         * bios in the queue, and before any successive bios.
         */
        if (__predict_false(bp->bio_flags & BIO_ORDERED)) {
                if (atomic_fetchadd_int(&ndisk->ordered_in_flight, 1) == 0 &&
                    ndisk->cur_depth == 0 && bioq_first(&ndisk->bioq) == NULL) {
                        nvd_bio_submit(ndisk, bp);
                        return;
                }
        } else if (__predict_true(ndisk->ordered_in_flight == 0)) {
                nvd_bio_submit(ndisk, bp);
                return;
        }

        /*
         * There are ordered bios in flight, so we need to submit
         *  bios through the task queue to enforce ordering.
         */
        mtx_lock(&ndisk->bioqlock);
        bioq_insert_tail(&ndisk->bioq, bp);
        mtx_unlock(&ndisk->bioqlock);
        taskqueue_enqueue(ndisk->tq, &ndisk->bioqtask);
}

static void
nvd_gone(struct nvd_disk *ndisk)
{
        struct bio      *bp;

        printf(NVD_STR"%u: detached\n", ndisk->unit);
        mtx_lock(&ndisk->bioqlock);
        disk_gone(ndisk->disk);
        while ((bp = bioq_takefirst(&ndisk->bioq)) != NULL) {
                if (__predict_false(bp->bio_flags & BIO_ORDERED))
                        atomic_add_int(&ndisk->ordered_in_flight, -1);
                bp->bio_error = ENXIO;
                bp->bio_flags |= BIO_ERROR;
                bp->bio_resid = bp->bio_bcount;
                biodone(bp);
        }
        mtx_unlock(&ndisk->bioqlock);
}

static void
nvd_gonecb(struct disk *dp)
{
        struct nvd_disk *ndisk = (struct nvd_disk *)dp->d_drv1;

        disk_destroy(ndisk->disk);
        mtx_lock(&nvd_lock);
        TAILQ_REMOVE(&disk_head, ndisk, global_tailq);
        TAILQ_REMOVE(&ndisk->ctrlr->disk_head, ndisk, ctrlr_tailq);
        if (TAILQ_EMPTY(&ndisk->ctrlr->disk_head))
                wakeup(&ndisk->ctrlr->disk_head);
        mtx_unlock(&nvd_lock);
        taskqueue_free(ndisk->tq);
        mtx_destroy(&ndisk->bioqlock);
        free(ndisk, M_NVD);
}

static int
nvd_ioctl(struct disk *dp, u_long cmd, void *data, int fflag,
    struct thread *td)
{
        struct nvd_disk         *ndisk = dp->d_drv1;

        return (nvme_ns_ioctl_process(ndisk->ns, cmd, data, fflag, td));
}

static int
nvd_dump(void *arg, void *virt, off_t offset, size_t len)
{
        struct disk *dp = arg;
        struct nvd_disk *ndisk = dp->d_drv1;

        return (nvme_ns_dump(ndisk->ns, virt, offset, len));
}

static int
nvd_getattr(struct bio *bp)
{
        struct nvd_disk *ndisk = (struct nvd_disk *)bp->bio_disk->d_drv1;
        const struct nvme_namespace_data *nsdata;
        u_int i;

        if (!strcmp("GEOM::lunid", bp->bio_attribute)) {
                nsdata = nvme_ns_get_data(ndisk->ns);

                /* Try to return NGUID as lunid. */
                for (i = 0; i < sizeof(nsdata->nguid); i++) {
                        if (nsdata->nguid[i] != 0)
                                break;
                }
                if (i < sizeof(nsdata->nguid)) {
                        if (bp->bio_length < sizeof(nsdata->nguid) * 2 + 1)
                                return (EFAULT);
                        for (i = 0; i < sizeof(nsdata->nguid); i++) {
                                sprintf(&bp->bio_data[i * 2], "%02x",
                                    nsdata->nguid[i]);
                        }
                        bp->bio_completed = bp->bio_length;
                        return (0);
                }

                /* Try to return EUI64 as lunid. */
                for (i = 0; i < sizeof(nsdata->eui64); i++) {
                        if (nsdata->eui64[i] != 0)
                                break;
                }
                if (i < sizeof(nsdata->eui64)) {
                        if (bp->bio_length < sizeof(nsdata->eui64) * 2 + 1)
                                return (EFAULT);
                        for (i = 0; i < sizeof(nsdata->eui64); i++) {
                                sprintf(&bp->bio_data[i * 2], "%02x",
                                    nsdata->eui64[i]);
                        }
                        bp->bio_completed = bp->bio_length;
                        return (0);
                }
        }
        return (-1);
}

static void
nvd_done(void *arg, const struct nvme_completion *cpl)
{
        struct bio *bp = (struct bio *)arg;
        struct nvd_disk *ndisk = bp->bio_disk->d_drv1;

        if (__predict_false(bp->bio_flags & BIO_ORDERED)) {
                atomic_add_int(&ndisk->cur_depth, -NVD_ODEPTH);
                atomic_add_int(&ndisk->ordered_in_flight, -1);
                wakeup(&ndisk->cur_depth);
        } else {
                if (atomic_fetchadd_int(&ndisk->cur_depth, -1) == 1 &&
                    __predict_false(ndisk->ordered_in_flight != 0))
                        wakeup(&ndisk->cur_depth);
        }

        biodone(bp);
}

static void
nvd_bioq_process(void *arg, int pending)
{
        struct nvd_disk *ndisk = arg;
        struct bio *bp;

        for (;;) {
                mtx_lock(&ndisk->bioqlock);
                bp = bioq_takefirst(&ndisk->bioq);
                mtx_unlock(&ndisk->bioqlock);
                if (bp == NULL)
                        break;

                if (__predict_false(bp->bio_flags & BIO_ORDERED)) {
                        /*
                         * bio with BIO_ORDERED flag set must be executed
                         * after all previous bios.
                         */
                        while (ndisk->cur_depth > 0)
                                tsleep(&ndisk->cur_depth, 0, "nvdorb", 1);
                } else {
                        /*
                         * bio with BIO_ORDERED flag set must be completed
                         * before proceeding with additional bios.
                         */
                        while (ndisk->cur_depth >= NVD_ODEPTH)
                                tsleep(&ndisk->cur_depth, 0, "nvdora", 1);
                }

                nvd_bio_submit(ndisk, bp);
        }
}

static int
nvdc_controller_failed(device_t dev)
{
        struct nvd_controller   *nvd_ctrlr = device_get_softc(dev);
        struct nvd_disk         *ndisk;

        mtx_lock(&nvd_lock);
        TAILQ_REMOVE(&ctrlr_head, nvd_ctrlr, tailq);
        TAILQ_FOREACH(ndisk, &nvd_ctrlr->disk_head, ctrlr_tailq)
                nvd_gone(ndisk);
        while (!TAILQ_EMPTY(&nvd_ctrlr->disk_head))
                msleep(&nvd_ctrlr->disk_head, &nvd_lock, 0, "nvd_fail", 0);
        mtx_unlock(&nvd_lock);
        return (0);
}

static int
nvdc_probe(device_t dev)
{
        if (!nvme_use_nvd)
                return (ENXIO);

        device_set_desc(dev, "nvme storage namespace");
        return (BUS_PROBE_DEFAULT);
}

static int
nvdc_attach(device_t dev)
{
        struct nvd_controller   *nvd_ctrlr = device_get_softc(dev);
        struct nvme_controller  *ctrlr = device_get_ivars(dev);

        nvd_ctrlr->ctrlr = ctrlr;
        TAILQ_INIT(&nvd_ctrlr->disk_head);
        mtx_lock(&nvd_lock);
        TAILQ_INSERT_TAIL(&ctrlr_head, nvd_ctrlr, tailq);
        mtx_unlock(&nvd_lock);

        return (0);
}

static int
nvdc_detach(device_t dev)
{
        return (nvdc_controller_failed(dev));
}

static struct nvd_disk *
nvd_nsid_to_disk(struct nvd_controller *nvd_ctrlr, uint32_t nsid)
{
        struct nvd_disk         *ndisk;

        mtx_lock(&nvd_lock);
        TAILQ_FOREACH(ndisk, &nvd_ctrlr->disk_head, ctrlr_tailq) {
                if (ndisk->ns->id != nsid)
                        continue;
                break;
        }
        mtx_unlock(&nvd_lock);
        return ndisk;
}

static struct nvd_disk *
nvd_ns_to_disk(struct nvd_controller *nvd_ctrlr, struct nvme_namespace *ns)
{
        struct nvd_disk         *ndisk;

        mtx_lock(&nvd_lock);
        TAILQ_FOREACH(ndisk, &nvd_ctrlr->disk_head, ctrlr_tailq) {
                if (ndisk->ns != ns)
                        continue;
                break;
        }
        mtx_unlock(&nvd_lock);
        return ndisk;
}

static int
nvdc_ns_added(device_t dev, struct nvme_namespace *ns)
{
        struct nvd_controller   *nvd_ctrlr = device_get_softc(dev);
        struct nvd_disk         *ndisk;
        uint8_t                 descr[NVME_MODEL_NUMBER_LENGTH+1];
        struct nvd_disk         *tnd;
        struct disk             *disk;
        device_t                 pdev = nvd_ctrlr->ctrlr->dev;
        int                      unit;

        ndisk = malloc(sizeof(struct nvd_disk), M_NVD, M_ZERO | M_WAITOK);
        ndisk->ctrlr = nvd_ctrlr;
        ndisk->ns = ns;
        ndisk->cur_depth = 0;
        ndisk->ordered_in_flight = 0;
        mtx_init(&ndisk->bioqlock, "nvd bioq lock", NULL, MTX_DEF);
        bioq_init(&ndisk->bioq);
        TASK_INIT(&ndisk->bioqtask, 0, nvd_bioq_process, ndisk);

        mtx_lock(&nvd_lock);
        unit = 0;
        TAILQ_FOREACH(tnd, &disk_head, global_tailq) {
                if (tnd->unit > unit)
                        break;
                unit = tnd->unit + 1;
        }
        ndisk->unit = unit;
        if (tnd != NULL)
                TAILQ_INSERT_BEFORE(tnd, ndisk, global_tailq);
        else
                TAILQ_INSERT_TAIL(&disk_head, ndisk, global_tailq);
        TAILQ_INSERT_TAIL(&nvd_ctrlr->disk_head, ndisk, ctrlr_tailq);
        mtx_unlock(&nvd_lock);

        ndisk->tq = taskqueue_create("nvd_taskq", M_WAITOK,
            taskqueue_thread_enqueue, &ndisk->tq);
        taskqueue_start_threads(&ndisk->tq, 1, PI_DISK, "nvd taskq");

        disk = ndisk->disk = disk_alloc();
        disk->d_strategy = nvd_strategy;
        disk->d_ioctl = nvd_ioctl;
        disk->d_dump = nvd_dump;
        disk->d_getattr = nvd_getattr;
        disk->d_gone = nvd_gonecb;
        disk->d_name = NVD_STR;
        disk->d_unit = ndisk->unit;
        disk->d_drv1 = ndisk;

        disk->d_sectorsize = nvme_ns_get_sector_size(ns);
        disk->d_mediasize = (off_t)nvme_ns_get_size(ns);
        disk->d_maxsize = nvme_ns_get_max_io_xfer_size(ns);
        disk->d_delmaxsize = (off_t)nvme_ns_get_size(ns);
        if (disk->d_delmaxsize > nvd_delete_max)
                disk->d_delmaxsize = nvd_delete_max;
        disk->d_stripesize = nvme_ns_get_stripesize(ns);
        disk->d_flags = DISKFLAG_UNMAPPED_BIO | DISKFLAG_DIRECT_COMPLETION;
        if (nvme_ns_get_flags(ns) & NVME_NS_DEALLOCATE_SUPPORTED)
                disk->d_flags |= DISKFLAG_CANDELETE;
        if (nvme_ns_get_flags(ns) & NVME_NS_FLUSH_SUPPORTED)
                disk->d_flags |= DISKFLAG_CANFLUSHCACHE;
        disk->d_devstat = devstat_new_entry(disk->d_name, disk->d_unit,
            disk->d_sectorsize, DEVSTAT_ALL_SUPPORTED,
            DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_NVME,
            DEVSTAT_PRIORITY_DISK);

        /*
         * d_ident and d_descr are both far bigger than the length of either
         *  the serial or model number strings.
         */
        nvme_strvis(disk->d_ident, nvme_ns_get_serial_number(ns),
            sizeof(disk->d_ident), NVME_SERIAL_NUMBER_LENGTH);
        nvme_strvis(descr, nvme_ns_get_model_number(ns), sizeof(descr),
            NVME_MODEL_NUMBER_LENGTH);
        strlcpy(disk->d_descr, descr, sizeof(descr));

        /*
         * For devices that are reported as children of the AHCI controller,
         * which has no access to the config space for this controller, report
         * the AHCI controller's data.
         */
        if (nvd_ctrlr->ctrlr->quirks & QUIRK_AHCI)
                pdev = device_get_parent(pdev);
        disk->d_hba_vendor = pci_get_vendor(pdev);
        disk->d_hba_device = pci_get_device(pdev);
        disk->d_hba_subvendor = pci_get_subvendor(pdev);
        disk->d_hba_subdevice = pci_get_subdevice(pdev);
        disk->d_rotation_rate = DISK_RR_NON_ROTATING;
        strlcpy(disk->d_attachment, device_get_nameunit(pdev),
            sizeof(disk->d_attachment));

        disk_create(disk, DISK_VERSION);

        printf(NVD_STR"%u: <%s> NVMe namespace\n", disk->d_unit, descr);
        printf(NVD_STR"%u: %juMB (%ju %u byte sectors)\n", disk->d_unit,
                (uintmax_t)disk->d_mediasize / (1024*1024),
                (uintmax_t)disk->d_mediasize / disk->d_sectorsize,
                disk->d_sectorsize);

        return (0);
}

static int
nvdc_ns_removed(device_t dev, struct nvme_namespace *ns)
{
        struct nvd_controller   *nvd_ctrlr = device_get_softc(dev);
        struct nvd_disk         *ndisk = nvd_ns_to_disk(nvd_ctrlr, ns);

        if (ndisk == NULL)
                panic("nvdc: no namespace found for ns  %p", ns);
        nvd_gone(ndisk);
        /* gonecb removes it from the list -- no need to wait */
        return (0);
}

static int
nvdc_ns_changed(device_t dev, uint32_t nsid)
{
        struct nvd_controller   *nvd_ctrlr = device_get_softc(dev);
        struct nvd_disk         *ndisk = nvd_nsid_to_disk(nvd_ctrlr, nsid);
        struct disk             *disk;
        struct nvme_namespace   *ns;

        if (ndisk == NULL)
                panic("nvdc: no namespace found for %d", nsid);
        disk = ndisk->disk;
        ns = ndisk->ns;

        disk->d_sectorsize = nvme_ns_get_sector_size(ns);
        disk->d_mediasize = (off_t)nvme_ns_get_size(ns);
        disk->d_maxsize = nvme_ns_get_max_io_xfer_size(ns);
        disk->d_delmaxsize = (off_t)nvme_ns_get_size(ns);
        if (disk->d_delmaxsize > nvd_delete_max)
                disk->d_delmaxsize = nvd_delete_max;

        disk_resize(disk, M_NOWAIT);

        printf(NVD_STR"%u: NVMe namespace resized\n", ndisk->unit);
        printf(NVD_STR"%u: %juMB (%ju %u byte sectors)\n", disk->d_unit,
                (uintmax_t)disk->d_mediasize / (1024*1024),
                (uintmax_t)disk->d_mediasize / disk->d_sectorsize,
                disk->d_sectorsize);
        return (0);
}

static int
nvdc_handle_aen(device_t dev, const struct nvme_completion *cpl,
    uint32_t pg_nr, void *page, uint32_t page_len)
{
        /* Do nothing */
        return (0);
}

static device_method_t nvdc_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         nvdc_probe),
        DEVMETHOD(device_attach,        nvdc_attach),
        DEVMETHOD(device_detach,        nvdc_detach),
        /* Nvme controller messages */
        DEVMETHOD(nvme_ns_added,        nvdc_ns_added),
        DEVMETHOD(nvme_ns_removed,      nvdc_ns_removed),
        DEVMETHOD(nvme_ns_changed,      nvdc_ns_changed),
        DEVMETHOD(nvme_controller_failed, nvdc_controller_failed),
        DEVMETHOD(nvme_handle_aen,      nvdc_handle_aen),
        DEVMETHOD_END
};

static driver_t nvdc_driver = {
        "nvdc",
        nvdc_methods,
        sizeof(struct nvd_controller),
};

DRIVER_MODULE(nvdc, nvme, nvdc_driver, NULL, NULL);