freebsd-skq/sys/cam/cam_sim.c

/*-
 * Common functions for SCSI Interface Modules (SIMs).
 *
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 1997 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/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/bus.h>

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_sim.h>
#include <cam/cam_queue.h>
#include <cam/cam_xpt.h>

#define CAM_PATH_ANY (u_int32_t)-1

static MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");

static struct mtx cam_sim_free_mtx;
MTX_SYSINIT(cam_sim_free_init, &cam_sim_free_mtx, "CAM SIM free lock", MTX_DEF);

struct cam_devq *
cam_simq_alloc(u_int32_t max_sim_transactions)
{
	return (cam_devq_alloc(/*size*/0, max_sim_transactions));
}

void
cam_simq_free(struct cam_devq *devq)
{
	cam_devq_free(devq);
}

struct cam_sim *
cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
	      const char *sim_name, void *softc, u_int32_t unit,
	      struct mtx *mtx, int max_dev_transactions,
	      int max_tagged_dev_transactions, struct cam_devq *queue)
{
	struct cam_sim *sim;

	sim = (struct cam_sim *)malloc(sizeof(struct cam_sim),
	    M_CAMSIM, M_ZERO | M_NOWAIT);

	if (sim == NULL)
		return (NULL);

	sim->sim_action = sim_action;
	sim->sim_poll = sim_poll;
	sim->sim_name = sim_name;
	sim->softc = softc;
	sim->path_id = CAM_PATH_ANY;
	sim->sim_dev = NULL;	/* set only by cam_sim_alloc_dev */
	sim->unit_number = unit;
	sim->bus_id = 0;	/* set in xpt_bus_register */
	sim->max_tagged_dev_openings = max_tagged_dev_transactions;
	sim->max_dev_openings = max_dev_transactions;
	sim->flags = 0;
	sim->refcount = 1;
	sim->devq = queue;
	sim->mtx = mtx;
	if (mtx == &Giant) {
		sim->flags |= 0;
		callout_init(&sim->callout, 0);
	} else {
		sim->flags |= CAM_SIM_MPSAFE;
		callout_init(&sim->callout, 1);
	}
	return (sim);
}

struct cam_sim *
cam_sim_alloc_dev(sim_action_func sim_action, sim_poll_func sim_poll,
	      const char *sim_name, void *softc, device_t dev,
	      struct mtx *mtx, int max_dev_transactions,
	      int max_tagged_dev_transactions, struct cam_devq *queue)
{
	struct cam_sim *sim;

	KASSERT(dev != NULL, ("%s: dev is null for sim_name %s softc %p\n",
	    __func__, sim_name, softc));

	sim = cam_sim_alloc(sim_action, sim_poll, sim_name, softc,
	    device_get_unit(dev), mtx, max_dev_transactions,
	    max_tagged_dev_transactions, queue);
	if (sim != NULL)
		sim->sim_dev = dev;
	return (sim);
}

void
cam_sim_free(struct cam_sim *sim, int free_devq)
{
	struct mtx *mtx = sim->mtx;
	int error;

	if (mtx) {
		mtx_assert(mtx, MA_OWNED);
	} else {
		mtx = &cam_sim_free_mtx;
		mtx_lock(mtx);
	}
	sim->refcount--;
	if (sim->refcount > 0) {
		error = msleep(sim, mtx, PRIBIO, "simfree", 0);
		KASSERT(error == 0, ("invalid error value for msleep(9)"));
	}
	KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
	if (sim->mtx == NULL)
		mtx_unlock(mtx);

	if (free_devq)
		cam_simq_free(sim->devq);
	free(sim, M_CAMSIM);
}

void
cam_sim_release(struct cam_sim *sim)
{
	struct mtx *mtx = sim->mtx;

	if (mtx) {
		if (!mtx_owned(mtx))
			mtx_lock(mtx);
		else
			mtx = NULL;
	} else {
		mtx = &cam_sim_free_mtx;
		mtx_lock(mtx);
	}
	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
	sim->refcount--;
	if (sim->refcount == 0)
		wakeup(sim);
	if (mtx)
		mtx_unlock(mtx);
}

void
cam_sim_hold(struct cam_sim *sim)
{
	struct mtx *mtx = sim->mtx;

	if (mtx) {
		if (!mtx_owned(mtx))
			mtx_lock(mtx);
		else
			mtx = NULL;
	} else {
		mtx = &cam_sim_free_mtx;
		mtx_lock(mtx);
	}
	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
	sim->refcount++;
	if (mtx)
		mtx_unlock(mtx);
}

void
cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
{
	sim->path_id = path_id;
}