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
46 static MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
47
48 static struct mtx cam_sim_free_mtx;
49 MTX_SYSINIT(cam_sim_free_init, &cam_sim_free_mtx, "CAM SIM free lock", MTX_DEF);
50
51 struct cam_devq *
cam_simq_alloc(uint32_t max_sim_transactions)52 cam_simq_alloc(uint32_t max_sim_transactions)
53 {
54 return (cam_devq_alloc(/*size*/0, max_sim_transactions));
55 }
56
57 void
cam_simq_free(struct cam_devq * devq)58 cam_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 */
99 struct cam_sim *
cam_sim_alloc(sim_action_func sim_action,sim_poll_func sim_poll,const char * sim_name,void * softc,uint32_t unit,struct mtx * mtx,int max_dev_transactions,int max_tagged_dev_transactions,struct cam_devq * queue)100 cam_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 */
140 void
cam_sim_free(struct cam_sim * sim,int free_devq)141 cam_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
168 void
cam_sim_release(struct cam_sim * sim)169 cam_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
189 void
cam_sim_hold(struct cam_sim * sim)190 cam_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
208 void
cam_sim_set_path(struct cam_sim * sim,uint32_t path_id)209 cam_sim_set_path(struct cam_sim *sim, uint32_t path_id)
210 {
211 sim->path_id = path_id;
212 }
213