/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Implementation of SCSI Processor Target Peripheral driver for CAM.
 *
 * Copyright (c) 1998 Justin T. Gibbs.
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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/queue.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/bio.h>
#include <sys/devicestat.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/ptio.h>

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_periph.h>
#include <cam/cam_xpt_periph.h>
#include <cam/cam_debug.h>

#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_message.h>
#include <cam/scsi/scsi_pt.h>

#include "opt_pt.h"

typedef enum {
        PT_STATE_PROBE,
        PT_STATE_NORMAL
} pt_state;

typedef enum {
        PT_FLAG_NONE            = 0x00,
        PT_FLAG_OPEN            = 0x01,
        PT_FLAG_DEVICE_INVALID  = 0x02,
        PT_FLAG_RETRY_UA        = 0x04
} pt_flags;

typedef enum {
        PT_CCB_BUFFER_IO        = 0x01,
        PT_CCB_RETRY_UA         = 0x04,
        PT_CCB_BUFFER_IO_UA     = PT_CCB_BUFFER_IO|PT_CCB_RETRY_UA
} pt_ccb_state;

/* Offsets into our private area for storing information */
#define ccb_state       ppriv_field0
#define ccb_bp          ppriv_ptr1

struct pt_softc {
        struct   bio_queue_head bio_queue;
        struct   devstat *device_stats;
        LIST_HEAD(, ccb_hdr) pending_ccbs;
        pt_state state;
        pt_flags flags; 
        int      io_timeout;
        struct cdev *dev;
};

static  d_open_t        ptopen;
static  d_close_t       ptclose;
static  d_strategy_t    ptstrategy;
static  periph_init_t   ptinit;
static  void            ptasync(void *callback_arg, uint32_t code,
                                struct cam_path *path, void *arg);
static  periph_ctor_t   ptctor;
static  periph_oninv_t  ptoninvalidate;
static  periph_dtor_t   ptdtor;
static  periph_start_t  ptstart;
static  void            ptdone(struct cam_periph *periph,
                               union ccb *done_ccb);
static  d_ioctl_t       ptioctl;
static  int             pterror(union ccb *ccb, uint32_t cam_flags,
                                uint32_t sense_flags);

void    scsi_send_receive(struct ccb_scsiio *csio, uint32_t retries,
                          void (*cbfcnp)(struct cam_periph *, union ccb *),
                          u_int tag_action, int readop, u_int byte2,
                          uint32_t xfer_len, uint8_t *data_ptr,
                          uint8_t sense_len, uint32_t timeout);

static struct periph_driver ptdriver =
{
        ptinit, "pt",
        TAILQ_HEAD_INITIALIZER(ptdriver.units), /* generation */ 0
};

PERIPHDRIVER_DECLARE(pt, ptdriver);

static struct cdevsw pt_cdevsw = {
        .d_version =    D_VERSION,
        .d_flags =      0,
        .d_open =       ptopen,
        .d_close =      ptclose,
        .d_read =       physread,
        .d_write =      physwrite,
        .d_ioctl =      ptioctl,
        .d_strategy =   ptstrategy,
        .d_name =       "pt",
};

#ifndef SCSI_PT_DEFAULT_TIMEOUT
#define SCSI_PT_DEFAULT_TIMEOUT         60
#endif

static int
ptopen(struct cdev *dev, int flags, int fmt, struct thread *td)
{
        struct cam_periph *periph;
        struct pt_softc *softc;
        int error = 0;

        periph = (struct cam_periph *)dev->si_drv1;
        if (cam_periph_acquire(periph) != 0)
                return (ENXIO); 

        softc = (struct pt_softc *)periph->softc;

        cam_periph_lock(periph);
        if (softc->flags & PT_FLAG_DEVICE_INVALID) {
                cam_periph_release_locked(periph);
                cam_periph_unlock(periph);
                return(ENXIO);
        }

        if ((softc->flags & PT_FLAG_OPEN) == 0)
                softc->flags |= PT_FLAG_OPEN;
        else {
                error = EBUSY;
                cam_periph_release(periph);
        }

        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE,
            ("ptopen: dev=%s\n", devtoname(dev)));

        cam_periph_unlock(periph);
        return (error);
}

static int
ptclose(struct cdev *dev, int flag, int fmt, struct thread *td)
{
        struct  cam_periph *periph;
        struct  pt_softc *softc;

        periph = (struct cam_periph *)dev->si_drv1;
        softc = (struct pt_softc *)periph->softc;

        cam_periph_lock(periph);

        softc->flags &= ~PT_FLAG_OPEN;
        cam_periph_release_locked(periph);
        cam_periph_unlock(periph);
        return (0);
}

/*
 * Actually translate the requested transfer into one the physical driver
 * can understand.  The transfer is described by a buf and will include
 * only one physical transfer.
 */
static void
ptstrategy(struct bio *bp)
{
        struct cam_periph *periph;
        struct pt_softc *softc;

        periph = (struct cam_periph *)bp->bio_dev->si_drv1;
        bp->bio_resid = bp->bio_bcount;
        if (periph == NULL) {
                biofinish(bp, NULL, ENXIO);
                return;
        }
        cam_periph_lock(periph);
        softc = (struct pt_softc *)periph->softc;

        /*
         * If the device has been made invalid, error out
         */
        if ((softc->flags & PT_FLAG_DEVICE_INVALID)) {
                cam_periph_unlock(periph);
                biofinish(bp, NULL, ENXIO);
                return;
        }

        /*
         * Place it in the queue of disk activities for this disk
         */
        bioq_insert_tail(&softc->bio_queue, bp);

        /*
         * Schedule ourselves for performing the work.
         */
        xpt_schedule(periph, CAM_PRIORITY_NORMAL);
        cam_periph_unlock(periph);

        return;
}

static void
ptinit(void)
{
        cam_status status;

        /*
         * Install a global async callback.  This callback will
         * receive async callbacks like "new device found".
         */
        status = xpt_register_async(AC_FOUND_DEVICE, ptasync, NULL, NULL);

        if (status != CAM_REQ_CMP) {
                printf("pt: Failed to attach master async callback "
                       "due to status 0x%x!\n", status);
        }
}

static cam_status
ptctor(struct cam_periph *periph, void *arg)
{
        struct pt_softc *softc;
        struct ccb_getdev *cgd;
        struct ccb_pathinq cpi;
        struct make_dev_args args;
        int error;

        cgd = (struct ccb_getdev *)arg;
        if (cgd == NULL) {
                printf("ptregister: no getdev CCB, can't register device\n");
                return(CAM_REQ_CMP_ERR);
        }

        softc = (struct pt_softc *)malloc(sizeof(*softc),M_DEVBUF,M_NOWAIT);

        if (softc == NULL) {
                printf("daregister: Unable to probe new device. "
                       "Unable to allocate softc\n");                           
                return(CAM_REQ_CMP_ERR);
        }

        bzero(softc, sizeof(*softc));
        LIST_INIT(&softc->pending_ccbs);
        softc->state = PT_STATE_NORMAL;
        bioq_init(&softc->bio_queue);

        softc->io_timeout = SCSI_PT_DEFAULT_TIMEOUT * 1000;

        periph->softc = softc;

        xpt_path_inq(&cpi, periph->path);

        cam_periph_unlock(periph);

        make_dev_args_init(&args);
        args.mda_devsw = &pt_cdevsw;
        args.mda_unit = periph->unit_number;
        args.mda_uid = UID_ROOT;
        args.mda_gid = GID_OPERATOR;
        args.mda_mode = 0600;
        args.mda_si_drv1 = periph;
        error = make_dev_s(&args, &softc->dev, "%s%d", periph->periph_name,
            periph->unit_number);
        if (error != 0) {
                cam_periph_lock(periph);
                return (CAM_REQ_CMP_ERR);
        }

        softc->device_stats = devstat_new_entry("pt",
                          periph->unit_number, 0,
                          DEVSTAT_NO_BLOCKSIZE,
                          SID_TYPE(&cgd->inq_data) |
                          XPORT_DEVSTAT_TYPE(cpi.transport),
                          DEVSTAT_PRIORITY_OTHER);

        cam_periph_lock(periph);

        /*
         * Add async callbacks for bus reset and
         * bus device reset calls.  I don't bother
         * checking if this fails as, in most cases,
         * the system will function just fine without
         * them and the only alternative would be to
         * not attach the device on failure.
         */
        xpt_register_async(AC_SENT_BDR | AC_BUS_RESET | AC_LOST_DEVICE,
                           ptasync, periph, periph->path);

        /* Tell the user we've attached to the device */
        xpt_announce_periph(periph, NULL);

        return(CAM_REQ_CMP);
}

static void
ptoninvalidate(struct cam_periph *periph)
{
        struct pt_softc *softc;

        softc = (struct pt_softc *)periph->softc;

        /*
         * De-register any async callbacks.
         */
        xpt_register_async(0, ptasync, periph, periph->path);

        softc->flags |= PT_FLAG_DEVICE_INVALID;

        /*
         * Return all queued I/O with ENXIO.
         * XXX Handle any transactions queued to the card
         *     with XPT_ABORT_CCB.
         */
        bioq_flush(&softc->bio_queue, NULL, ENXIO);
}

static void
ptdtor(struct cam_periph *periph)
{
        struct pt_softc *softc;

        softc = (struct pt_softc *)periph->softc;

        devstat_remove_entry(softc->device_stats);
        cam_periph_unlock(periph);
        destroy_dev(softc->dev);
        cam_periph_lock(periph);
        free(softc, M_DEVBUF);
}

static void
ptasync(void *callback_arg, uint32_t code, struct cam_path *path, void *arg)
{
        struct cam_periph *periph;

        periph = (struct cam_periph *)callback_arg;
        switch (code) {
        case AC_FOUND_DEVICE:
        {
                struct ccb_getdev *cgd;
                cam_status status;

                cgd = (struct ccb_getdev *)arg;
                if (cgd == NULL)
                        break;

                if (cgd->protocol != PROTO_SCSI)
                        break;
                if (SID_QUAL(&cgd->inq_data) != SID_QUAL_LU_CONNECTED)
                        break;
                if (SID_TYPE(&cgd->inq_data) != T_PROCESSOR)
                        break;

                /*
                 * Allocate a peripheral instance for
                 * this device and start the probe
                 * process.
                 */
                status = cam_periph_alloc(ptctor, ptoninvalidate, ptdtor,
                                          ptstart, "pt", CAM_PERIPH_BIO,
                                          path, ptasync,
                                          AC_FOUND_DEVICE, cgd);

                if (status != CAM_REQ_CMP
                 && status != CAM_REQ_INPROG)
                        printf("ptasync: Unable to attach to new device "
                                "due to status 0x%x\n", status);
                break;
        }
        case AC_SENT_BDR:
        case AC_BUS_RESET:
        {
                struct pt_softc *softc;
                struct ccb_hdr *ccbh;

                softc = (struct pt_softc *)periph->softc;
                /*
                 * Don't fail on the expected unit attention
                 * that will occur.
                 */
                softc->flags |= PT_FLAG_RETRY_UA;
                LIST_FOREACH(ccbh, &softc->pending_ccbs, periph_links.le)
                        ccbh->ccb_state |= PT_CCB_RETRY_UA;
        }
        /* FALLTHROUGH */
        default:
                cam_periph_async(periph, code, path, arg);
                break;
        }
}

static void
ptstart(struct cam_periph *periph, union ccb *start_ccb)
{
        struct pt_softc *softc;
        struct bio *bp;

        softc = (struct pt_softc *)periph->softc;

        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE, ("ptstart\n"));

        /*
         * See if there is a buf with work for us to do..
         */
        bp = bioq_first(&softc->bio_queue);
        if (bp == NULL) {
                xpt_release_ccb(start_ccb);
        } else {
                bioq_remove(&softc->bio_queue, bp);

                devstat_start_transaction_bio(softc->device_stats, bp);

                scsi_send_receive(&start_ccb->csio,
                                  /*retries*/4,
                                  ptdone,
                                  MSG_SIMPLE_Q_TAG,
                                  bp->bio_cmd == BIO_READ,
                                  /*byte2*/0,
                                  bp->bio_bcount,
                                  bp->bio_data,
                                  /*sense_len*/SSD_FULL_SIZE,
                                  /*timeout*/softc->io_timeout);

                start_ccb->ccb_h.ccb_state = PT_CCB_BUFFER_IO_UA;

                /*
                 * Block out any asynchronous callbacks
                 * while we touch the pending ccb list.
                 */
                LIST_INSERT_HEAD(&softc->pending_ccbs, &start_ccb->ccb_h,
                                 periph_links.le);

                start_ccb->ccb_h.ccb_bp = bp;
                bp = bioq_first(&softc->bio_queue);

                xpt_action(start_ccb);
                
                if (bp != NULL) {
                        /* Have more work to do, so ensure we stay scheduled */
                        xpt_schedule(periph, CAM_PRIORITY_NORMAL);
                }
        }
}

static void
ptdone(struct cam_periph *periph, union ccb *done_ccb)
{
        struct pt_softc *softc;
        struct ccb_scsiio *csio;

        softc = (struct pt_softc *)periph->softc;

        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE, ("ptdone\n"));

        csio = &done_ccb->csio;
        switch (csio->ccb_h.ccb_state) {
        case PT_CCB_BUFFER_IO:
        case PT_CCB_BUFFER_IO_UA:
        {
                struct bio *bp;

                bp = (struct bio *)done_ccb->ccb_h.ccb_bp;
                if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        int error;
                        int sf;
                        
                        if ((csio->ccb_h.ccb_state & PT_CCB_RETRY_UA) != 0)
                                sf = SF_RETRY_UA;
                        else
                                sf = 0;

                        error = pterror(done_ccb, CAM_RETRY_SELTO, sf);
                        if (error == ERESTART) {
                                /*
                                 * A retry was scheuled, so
                                 * just return.
                                 */
                                return;
                        }
                        if (error != 0) {
                                if (error == ENXIO) {
                                        /*
                                         * Catastrophic error.  Mark our device
                                         * as invalid.
                                         */
                                        xpt_print(periph->path,
                                            "Invalidating device\n");
                                        softc->flags |= PT_FLAG_DEVICE_INVALID;
                                }

                                /*
                                 * return all queued I/O with EIO, so that
                                 * the client can retry these I/Os in the
                                 * proper order should it attempt to recover.
                                 */
                                bioq_flush(&softc->bio_queue, NULL, EIO);
                                bp->bio_error = error;
                                bp->bio_resid = bp->bio_bcount;
                                bp->bio_flags |= BIO_ERROR;
                        } else {
                                bp->bio_resid = csio->resid;
                                bp->bio_error = 0;
                                if (bp->bio_resid != 0) {
                                        /* Short transfer ??? */
                                        bp->bio_flags |= BIO_ERROR;
                                }
                        }
                        if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                                cam_release_devq(done_ccb->ccb_h.path,
                                                 /*relsim_flags*/0,
                                                 /*reduction*/0,
                                                 /*timeout*/0,
                                                 /*getcount_only*/0);
                } else {
                        bp->bio_resid = csio->resid;
                        if (bp->bio_resid != 0)
                                bp->bio_flags |= BIO_ERROR;
                }

                /*
                 * Block out any asynchronous callbacks
                 * while we touch the pending ccb list.
                 */
                LIST_REMOVE(&done_ccb->ccb_h, periph_links.le);

                biofinish(bp, softc->device_stats, 0);
                break;
        }
        }
        xpt_release_ccb(done_ccb);
}

static int
pterror(union ccb *ccb, uint32_t cam_flags, uint32_t sense_flags)
{

        return(cam_periph_error(ccb, cam_flags, sense_flags));
}

static int
ptioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
{
        struct cam_periph *periph;
        struct pt_softc *softc;
        int error = 0;

        periph = (struct cam_periph *)dev->si_drv1;
        softc = (struct pt_softc *)periph->softc;

        cam_periph_lock(periph);

        switch(cmd) {
        case PTIOCGETTIMEOUT:
                if (softc->io_timeout >= 1000)
                        *(int *)addr = softc->io_timeout / 1000;
                else
                        *(int *)addr = 0;
                break;
        case PTIOCSETTIMEOUT:
                if (*(int *)addr < 1) {
                        error = EINVAL;
                        break;
                }

                softc->io_timeout = *(int *)addr * 1000;

                break;
        default:
                error = cam_periph_ioctl(periph, cmd, addr, pterror);
                break;
        }

        cam_periph_unlock(periph);

        return(error);
}

void
scsi_send_receive(struct ccb_scsiio *csio, uint32_t retries,
                  void (*cbfcnp)(struct cam_periph *, union ccb *),
                  u_int tag_action, int readop, u_int byte2,
                  uint32_t xfer_len, uint8_t *data_ptr, uint8_t sense_len,
                  uint32_t timeout)
{
        struct scsi_send_receive *scsi_cmd;

        scsi_cmd = (struct scsi_send_receive *)&csio->cdb_io.cdb_bytes;
        scsi_cmd->opcode = readop ? RECEIVE : SEND;
        scsi_cmd->byte2 = byte2;
        scsi_ulto3b(xfer_len, scsi_cmd->xfer_len);
        scsi_cmd->control = 0;

        cam_fill_csio(csio,
                      retries,
                      cbfcnp,
                      /*flags*/readop ? CAM_DIR_IN : CAM_DIR_OUT,
                      tag_action,
                      data_ptr,
                      xfer_len,
                      sense_len,
                      sizeof(*scsi_cmd),
                      timeout);
}