/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2014 Alexander Motin <mav@FreeBSD.org>
 * Copyright (c) 2004, 2005 Silicon Graphics International Corp.
 * 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,
 *    without modification, immediately at the beginning of the file.
 * 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 ``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 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/systm.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/queue.h>
#include <sys/sysctl.h>

#include <cam/cam.h>
#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_da.h>
#include <cam/ctl/ctl_io.h>
#include <cam/ctl/ctl.h>
#include <cam/ctl/ctl_frontend.h>
#include <cam/ctl/ctl_util.h>
#include <cam/ctl/ctl_backend.h>
#include <cam/ctl/ctl_ioctl.h>
#include <cam/ctl/ctl_ha.h>
#include <cam/ctl/ctl_private.h>
#include <cam/ctl/ctl_debug.h>
#include <cam/ctl/ctl_scsi_all.h>
#include <cam/ctl/ctl_tpc.h>
#include <cam/ctl/ctl_error.h>

struct tpcl_softc {
        struct ctl_port port;
        u_int cur_tag_num;
};

static struct tpcl_softc tpcl_softc;

static int tpcl_init(void);
static int tpcl_shutdown(void);
static void tpcl_datamove(union ctl_io *io);
static void tpcl_done(union ctl_io *io);

static struct ctl_frontend tpcl_frontend =
{
        .name = "tpc",
        .init = tpcl_init,
        .shutdown = tpcl_shutdown,
};
CTL_FRONTEND_DECLARE(ctltpc, tpcl_frontend);

static int
tpcl_init(void)
{
        struct tpcl_softc *tsoftc = &tpcl_softc;
        struct ctl_port *port;
        struct scsi_transportid_spi *tid;
        int error, len;

        memset(tsoftc, 0, sizeof(*tsoftc));

        port = &tsoftc->port;
        port->frontend = &tpcl_frontend;
        port->port_type = CTL_PORT_INTERNAL;
        port->num_requested_ctl_io = 100;
        port->port_name = "tpc";
        port->fe_datamove = tpcl_datamove;
        port->fe_done = tpcl_done;
        port->targ_port = -1;
        port->max_initiators = 1;

        if ((error = ctl_port_register(port)) != 0) {
                printf("%s: tpc port registration failed\n", __func__);
                return (error);
        }

        len = sizeof(struct scsi_transportid_spi);
        port->init_devid = malloc(sizeof(struct ctl_devid) + len,
            M_CTL, M_WAITOK | M_ZERO);
        port->init_devid->len = len;
        tid = (struct scsi_transportid_spi *)port->init_devid->data;
        tid->format_protocol = SCSI_TRN_SPI_FORMAT_DEFAULT | SCSI_PROTO_SPI;
        scsi_ulto2b(0, tid->scsi_addr);
        scsi_ulto2b(port->targ_port, tid->rel_trgt_port_id);

        ctl_port_online(port);
        return (0);
}

static int
tpcl_shutdown(void)
{
        struct tpcl_softc *tsoftc = &tpcl_softc;
        struct ctl_port *port = &tsoftc->port;
        int error;

        ctl_port_offline(port);
        if ((error = ctl_port_deregister(port)) != 0)
                printf("%s: tpc port deregistration failed\n", __func__);
        return (error);
}

static void
tpcl_datamove(union ctl_io *io)
{
        struct ctl_sg_entry *ext_sglist, *kern_sglist;
        struct ctl_sg_entry ext_entry, kern_entry;
        int ext_sg_entries, kern_sg_entries;
        int ext_sg_start, ext_offset;
        int len_to_copy;
        int kern_watermark, ext_watermark;
        struct ctl_scsiio *ctsio;
        int i, j;

        CTL_DEBUG_PRINT(("%s\n", __func__));

        ctsio = &io->scsiio;

        /*
         * If this is the case, we're probably doing a BBR read and don't
         * actually need to transfer the data.  This will effectively
         * bit-bucket the data.
         */
        if (ctsio->ext_data_ptr == NULL)
                goto bailout;

        /*
         * To simplify things here, if we have a single buffer, stick it in
         * a S/G entry and just make it a single entry S/G list.
         */
        if (ctsio->ext_sg_entries > 0) {
                int len_seen;

                ext_sglist = (struct ctl_sg_entry *)ctsio->ext_data_ptr;
                ext_sg_entries = ctsio->ext_sg_entries;
                ext_sg_start = 0;
                ext_offset = 0;
                len_seen = 0;
                for (i = 0; i < ext_sg_entries; i++) {
                        if ((len_seen + ext_sglist[i].len) >=
                             ctsio->ext_data_filled) {
                                ext_sg_start = i;
                                ext_offset = ctsio->ext_data_filled - len_seen;
                                break;
                        }
                        len_seen += ext_sglist[i].len;
                }
        } else {
                ext_sglist = &ext_entry;
                ext_sglist->addr = ctsio->ext_data_ptr;
                ext_sglist->len = ctsio->ext_data_len;
                ext_sg_entries = 1;
                ext_sg_start = 0;
                ext_offset = ctsio->ext_data_filled;
        }

        if (ctsio->kern_sg_entries > 0) {
                kern_sglist = (struct ctl_sg_entry *)ctsio->kern_data_ptr;
                kern_sg_entries = ctsio->kern_sg_entries;
        } else {
                kern_sglist = &kern_entry;
                kern_sglist->addr = ctsio->kern_data_ptr;
                kern_sglist->len = ctsio->kern_data_len;
                kern_sg_entries = 1;
        }

        kern_watermark = 0;
        ext_watermark = ext_offset;
        for (i = ext_sg_start, j = 0;
             i < ext_sg_entries && j < kern_sg_entries;) {
                uint8_t *ext_ptr, *kern_ptr;

                len_to_copy = min(ext_sglist[i].len - ext_watermark,
                                  kern_sglist[j].len - kern_watermark);

                ext_ptr = (uint8_t *)ext_sglist[i].addr;
                ext_ptr = ext_ptr + ext_watermark;
                if (io->io_hdr.flags & CTL_FLAG_BUS_ADDR) {
                        /*
                         * XXX KDM fix this!
                         */
                        panic("need to implement bus address support");
#if 0
                        kern_ptr = bus_to_virt(kern_sglist[j].addr);
#endif
                } else
                        kern_ptr = (uint8_t *)kern_sglist[j].addr;
                kern_ptr = kern_ptr + kern_watermark;

                if ((ctsio->io_hdr.flags & CTL_FLAG_DATA_MASK) ==
                     CTL_FLAG_DATA_IN) {
                        CTL_DEBUG_PRINT(("%s: copying %d bytes to user\n",
                                         __func__, len_to_copy));
                        CTL_DEBUG_PRINT(("%s: from %p to %p\n", __func__,
                                         kern_ptr, ext_ptr));
                        memcpy(ext_ptr, kern_ptr, len_to_copy);
                } else {
                        CTL_DEBUG_PRINT(("%s: copying %d bytes from user\n",
                                         __func__, len_to_copy));
                        CTL_DEBUG_PRINT(("%s: from %p to %p\n", __func__,
                                         ext_ptr, kern_ptr));
                        memcpy(kern_ptr, ext_ptr, len_to_copy);
                }

                ctsio->ext_data_filled += len_to_copy;
                ctsio->kern_data_resid -= len_to_copy;

                ext_watermark += len_to_copy;
                if (ext_sglist[i].len == ext_watermark) {
                        i++;
                        ext_watermark = 0;
                }

                kern_watermark += len_to_copy;
                if (kern_sglist[j].len == kern_watermark) {
                        j++;
                        kern_watermark = 0;
                }
        }

        CTL_DEBUG_PRINT(("%s: ext_sg_entries: %d, kern_sg_entries: %d\n",
                         __func__, ext_sg_entries, kern_sg_entries));
        CTL_DEBUG_PRINT(("%s: ext_data_len = %d, kern_data_len = %d\n",
                         __func__, ctsio->ext_data_len, ctsio->kern_data_len));

bailout:
        ctl_datamove_done(io, true);
}

static void
tpcl_done(union ctl_io *io)
{

        tpc_done(io);
}

uint64_t
tpcl_resolve(struct ctl_softc *softc, int init_port,
    struct scsi_ec_cscd *cscd, uint32_t *ss, uint32_t *ps, uint32_t *pso)
{
        struct scsi_ec_cscd_id *cscdid;
        struct ctl_port *port;
        struct ctl_lun *lun;
        uint64_t lunid = UINT64_MAX;

        if (cscd->type_code != EC_CSCD_ID ||
            (cscd->luidt_pdt & EC_LUIDT_MASK) != EC_LUIDT_LUN ||
            (cscd->luidt_pdt & EC_NUL) != 0)
                return (lunid);

        cscdid = (struct scsi_ec_cscd_id *)cscd;
        mtx_lock(&softc->ctl_lock);
        if (init_port >= 0)
                port = softc->ctl_ports[init_port];
        else
                port = NULL;
        STAILQ_FOREACH(lun, &softc->lun_list, links) {
                if (port != NULL &&
                    ctl_lun_map_to_port(port, lun->lun) == UINT32_MAX)
                        continue;
                if (lun->lun_devid == NULL)
                        continue;
                if (scsi_devid_match(lun->lun_devid->data,
                    lun->lun_devid->len, &cscdid->codeset,
                    cscdid->length + 4) == 0) {
                        lunid = lun->lun;
                        if (ss)
                                *ss = lun->be_lun->blocksize;
                        if (ps)
                                *ps = lun->be_lun->blocksize <<
                                    lun->be_lun->pblockexp;
                        if (pso)
                                *pso = lun->be_lun->blocksize *
                                    lun->be_lun->pblockoff;
                        break;
                }
        }
        mtx_unlock(&softc->ctl_lock);
        return (lunid);
};

union ctl_io *
tpcl_alloc_io(void)
{
        struct tpcl_softc *tsoftc = &tpcl_softc;

        return (ctl_alloc_io(tsoftc->port.ctl_pool_ref));
};

int
tpcl_queue(union ctl_io *io, uint64_t lun)
{
        struct tpcl_softc *tsoftc = &tpcl_softc;

        io->io_hdr.nexus.initid = 0;
        io->io_hdr.nexus.targ_port = tsoftc->port.targ_port;
        io->io_hdr.nexus.targ_lun = lun;
        io->scsiio.tag_num = atomic_fetchadd_int(&tsoftc->cur_tag_num, 1);
        io->scsiio.ext_data_filled = 0;
        return (ctl_queue(io));
}