1/*-
2 * Common functions for SCSI Interface Modules (SIMs).
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * Copyright (c) 1997 Justin T. Gibbs.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions, and the following disclaimer,
14 *    without modification, immediately at the beginning of the file.
15 * 2. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/param.h>
32#include <sys/bus.h>
33#include <sys/kernel.h>
34#include <sys/lock.h>
35#include <sys/malloc.h>
36#include <sys/mutex.h>
37
38#include <cam/cam.h>
39#include <cam/cam_ccb.h>
40#include <cam/cam_queue.h>
41#include <cam/cam_sim.h>
42#include <cam/cam_xpt.h>
43
44#define CAM_PATH_ANY (uint32_t)-1
45
46static MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
47
48static struct mtx cam_sim_free_mtx;
49MTX_SYSINIT(cam_sim_free_init, &cam_sim_free_mtx, "CAM SIM free lock", MTX_DEF);
50
51struct cam_devq *
52cam_simq_alloc(uint32_t max_sim_transactions)
53{
54	return (cam_devq_alloc(/*size*/0, max_sim_transactions));
55}
56
57void
58cam_simq_free(struct cam_devq *devq)
59{
60	cam_devq_free(devq);
61}
62
63
64
65/**
66 * @brief allocate a new sim and fill in the details
67 *
68 * A Storage Interface Module (SIM) is the interface between CAM and
69 * hardware. SIM receives CCBs from CAM via @p sim_action callback and
70 * translates them into DMA or other hardware transactions.  During system
71 * dumps, it can be polled with the @p sim_poll callback. CCB processing is
72 * terminated by calling @c xpt_done().
73 *
74 * The @p mtx acts as a perimeter lock for the SIM. All calls into the SIM's
75 * @p sim_action are made with this lock held. It is also used to hold/release
76 * a SIM, managing its reference count. When the lock is NULL, the SIM is 100%
77 * responsible for locking (and the reference counting is done with a shared
78 * lock.
79 *
80 * The cam_devq passed in (@c queue) is used to arbitrate the number of
81 * outstanding transactions to the SIM. For HBAs that have global limits shared
82 * between the different buses, the same devq should be specified for each bus
83 * attached to the SIM.
84 *
85 * @param sim_action	Function to call to process CCBs
86 * @param sim_poll	Function to poll the hardware for completions
87 * @param sim_name	Name of SIM class
88 * @param softc		Software context associated with the SIM
89 * @param unit		Unit number of SIM
90 * @param mtx		Mutex to lock while interacting with the SIM, or NULL
91 *			for a SIM that handle its own locking to enable multi
92 *			queue support.
93 * @param max_dev_transactions Maximum number of concurrent untagged
94 *			transactions possible
95 * @param max_tagged_dev_transactions Maximum number of concurrent tagged
96 *			transactions possible.
97 * @param queue		The cam_devq to use for this SIM.
98 */
99struct cam_sim *
100cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
101	      const char *sim_name, void *softc, uint32_t unit,
102	      struct mtx *mtx, int max_dev_transactions,
103	      int max_tagged_dev_transactions, struct cam_devq *queue)
104{
105	struct cam_sim *sim;
106
107	sim = malloc(sizeof(struct cam_sim), M_CAMSIM, M_ZERO | M_NOWAIT);
108	if (sim == NULL)
109		return (NULL);
110
111	sim->sim_action = sim_action;
112	sim->sim_poll = sim_poll;
113	sim->sim_name = sim_name;
114	sim->softc = softc;
115	sim->path_id = CAM_PATH_ANY;
116	sim->unit_number = unit;
117	sim->bus_id = 0;	/* set in xpt_bus_register */
118	sim->max_tagged_dev_openings = max_tagged_dev_transactions;
119	sim->max_dev_openings = max_dev_transactions;
120	sim->flags = 0;
121	sim->refcount = 1;
122	sim->devq = queue;
123	sim->mtx = mtx;
124	return (sim);
125}
126
127/**
128 * @brief frees up the sim
129 *
130 * Frees up the CAM @c sim and optionally the devq. If a mutex is associated
131 * with the sim, it must be locked on entry. It will remain locked on
132 * return.
133 *
134 * This function will wait for all outstanding reference to the sim to clear
135 * before returning.
136 *
137 * @param sim          The sim to free
138 * @param free_devq    Free the devq associated with the sim at creation.
139 */
140void
141cam_sim_free(struct cam_sim *sim, int free_devq)
142{
143	struct mtx *mtx;
144	int error __diagused;
145
146	if (sim->mtx == NULL) {
147		mtx = &cam_sim_free_mtx;
148		mtx_lock(mtx);
149	} else {
150		mtx = sim->mtx;
151		mtx_assert(mtx, MA_OWNED);
152	}
153	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
154	sim->refcount--;
155	if (sim->refcount > 0) {
156		error = msleep(sim, mtx, PRIBIO, "simfree", 0);
157		KASSERT(error == 0, ("invalid error value for msleep(9)"));
158	}
159	KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
160	if (mtx == &cam_sim_free_mtx)	/* sim->mtx == NULL */
161		mtx_unlock(mtx);
162
163	if (free_devq)
164		cam_simq_free(sim->devq);
165	free(sim, M_CAMSIM);
166}
167
168void
169cam_sim_release(struct cam_sim *sim)
170{
171	struct mtx *mtx;
172
173	if (sim->mtx == NULL)
174		mtx = &cam_sim_free_mtx;
175	else if (!mtx_owned(sim->mtx))
176		mtx = sim->mtx;
177	else
178		mtx = NULL;	/* We hold the lock. */
179	if (mtx)
180		mtx_lock(mtx);
181	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
182	sim->refcount--;
183	if (sim->refcount == 0)
184		wakeup(sim);
185	if (mtx)
186		mtx_unlock(mtx);
187}
188
189void
190cam_sim_hold(struct cam_sim *sim)
191{
192	struct mtx *mtx;
193
194	if (sim->mtx == NULL)
195		mtx = &cam_sim_free_mtx;
196	else if (!mtx_owned(sim->mtx))
197		mtx = sim->mtx;
198	else
199		mtx = NULL;	/* We hold the lock. */
200	if (mtx)
201		mtx_lock(mtx);
202	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
203	sim->refcount++;
204	if (mtx)
205		mtx_unlock(mtx);
206}
207
208void
209cam_sim_set_path(struct cam_sim *sim, uint32_t path_id)
210{
211	sim->path_id = path_id;
212}
213