xref: /freebsd/sys/cam/cam_sim.c (revision 535af610)
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/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/bus.h>
36 #include <sys/kernel.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/mutex.h>
40 
41 #include <cam/cam.h>
42 #include <cam/cam_ccb.h>
43 #include <cam/cam_queue.h>
44 #include <cam/cam_sim.h>
45 #include <cam/cam_xpt.h>
46 
47 #define CAM_PATH_ANY (uint32_t)-1
48 
49 static MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
50 
51 static struct mtx cam_sim_free_mtx;
52 MTX_SYSINIT(cam_sim_free_init, &cam_sim_free_mtx, "CAM SIM free lock", MTX_DEF);
53 
54 struct cam_devq *
55 cam_simq_alloc(uint32_t max_sim_transactions)
56 {
57 	return (cam_devq_alloc(/*size*/0, max_sim_transactions));
58 }
59 
60 void
61 cam_simq_free(struct cam_devq *devq)
62 {
63 	cam_devq_free(devq);
64 }
65 
66 
67 
68 /**
69  * @brief allocate a new sim and fill in the details
70  *
71  * A Storage Interface Module (SIM) is the interface between CAM and
72  * hardware. SIM receives CCBs from CAM via @p sim_action callback and
73  * translates them into DMA or other hardware transactions.  During system
74  * dumps, it can be polled with the @p sim_poll callback. CCB processing is
75  * terminated by calling @c xpt_done().
76  *
77  * The @p mtx acts as a perimeter lock for the SIM. All calls into the SIM's
78  * @p sim_action are made with this lock held. It is also used to hold/release
79  * a SIM, managing its reference count. When the lock is NULL, the SIM is 100%
80  * responsible for locking (and the reference counting is done with a shared
81  * lock.
82  *
83  * The cam_devq passed in (@c queue) is used to arbitrate the number of
84  * outstanding transactions to the SIM. For HBAs that have global limits shared
85  * between the different buses, the same devq should be specified for each bus
86  * attached to the SIM.
87  *
88  * @param sim_action	Function to call to process CCBs
89  * @param sim_poll	Function to poll the hardware for completions
90  * @param sim_name	Name of SIM class
91  * @param softc		Software context associated with the SIM
92  * @param unit		Unit number of SIM
93  * @param mtx		Mutex to lock while interacting with the SIM, or NULL
94  *			for a SIM that handle its own locking to enable multi
95  *			queue support.
96  * @param max_dev_transactions Maximum number of concurrent untagged
97  *			transactions possible
98  * @param max_tagged_dev_transactions Maximum number of concurrent tagged
99  *			transactions possible.
100  * @param queue		The cam_devq to use for this SIM.
101  */
102 struct cam_sim *
103 cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
104 	      const char *sim_name, void *softc, uint32_t unit,
105 	      struct mtx *mtx, int max_dev_transactions,
106 	      int max_tagged_dev_transactions, struct cam_devq *queue)
107 {
108 	struct cam_sim *sim;
109 
110 	sim = malloc(sizeof(struct cam_sim), M_CAMSIM, M_ZERO | M_NOWAIT);
111 	if (sim == NULL)
112 		return (NULL);
113 
114 	sim->sim_action = sim_action;
115 	sim->sim_poll = sim_poll;
116 	sim->sim_name = sim_name;
117 	sim->softc = softc;
118 	sim->path_id = CAM_PATH_ANY;
119 	sim->unit_number = unit;
120 	sim->bus_id = 0;	/* set in xpt_bus_register */
121 	sim->max_tagged_dev_openings = max_tagged_dev_transactions;
122 	sim->max_dev_openings = max_dev_transactions;
123 	sim->flags = 0;
124 	sim->refcount = 1;
125 	sim->devq = queue;
126 	sim->mtx = mtx;
127 	return (sim);
128 }
129 
130 /**
131  * @brief frees up the sim
132  *
133  * Frees up the CAM @c sim and optionally the devq. If a mutex is associated
134  * with the sim, it must be locked on entry. It will remain locked on
135  * return.
136  *
137  * This function will wait for all outstanding reference to the sim to clear
138  * before returning.
139  *
140  * @param sim          The sim to free
141  * @param free_devq    Free the devq associated with the sim at creation.
142  */
143 void
144 cam_sim_free(struct cam_sim *sim, int free_devq)
145 {
146 	struct mtx *mtx;
147 	int error __diagused;
148 
149 	if (sim->mtx == NULL) {
150 		mtx = &cam_sim_free_mtx;
151 		mtx_lock(mtx);
152 	} else {
153 		mtx = sim->mtx;
154 		mtx_assert(mtx, MA_OWNED);
155 	}
156 	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
157 	sim->refcount--;
158 	if (sim->refcount > 0) {
159 		error = msleep(sim, mtx, PRIBIO, "simfree", 0);
160 		KASSERT(error == 0, ("invalid error value for msleep(9)"));
161 	}
162 	KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
163 	if (mtx == &cam_sim_free_mtx)	/* sim->mtx == NULL */
164 		mtx_unlock(mtx);
165 
166 	if (free_devq)
167 		cam_simq_free(sim->devq);
168 	free(sim, M_CAMSIM);
169 }
170 
171 void
172 cam_sim_release(struct cam_sim *sim)
173 {
174 	struct mtx *mtx;
175 
176 	if (sim->mtx == NULL)
177 		mtx = &cam_sim_free_mtx;
178 	else if (!mtx_owned(sim->mtx))
179 		mtx = sim->mtx;
180 	else
181 		mtx = NULL;	/* We hold the lock. */
182 	if (mtx)
183 		mtx_lock(mtx);
184 	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
185 	sim->refcount--;
186 	if (sim->refcount == 0)
187 		wakeup(sim);
188 	if (mtx)
189 		mtx_unlock(mtx);
190 }
191 
192 void
193 cam_sim_hold(struct cam_sim *sim)
194 {
195 	struct mtx *mtx;
196 
197 	if (sim->mtx == NULL)
198 		mtx = &cam_sim_free_mtx;
199 	else if (!mtx_owned(sim->mtx))
200 		mtx = sim->mtx;
201 	else
202 		mtx = NULL;	/* We hold the lock. */
203 	if (mtx)
204 		mtx_lock(mtx);
205 	KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
206 	sim->refcount++;
207 	if (mtx)
208 		mtx_unlock(mtx);
209 }
210 
211 void
212 cam_sim_set_path(struct cam_sim *sim, uint32_t path_id)
213 {
214 	sim->path_id = path_id;
215 }
216