FreeBSD/Linux Kernel Cross Reference
sys/cam/cam_sim.c
1 /*-
2 * Common functions for SCSI Interface Modules (SIMs).
3 *
4 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 (u_int32_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(u_int32_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, u_int32_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, u_int32_t path_id)
213 {
214 sim->path_id = path_id;
215 }
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