/*-
 * 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/cdefs.h>
__FBSDID("$FreeBSD$");

#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);
}