1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <sys/kmem.h>
28 #include <sys/types.h>
29 #include <sys/conf.h>
30 #include <sys/ddi.h>
31 #include <sys/sunddi.h>
32
33 #include <sys/ioat.h>
34
35
36 /* structure used to keep track of resources */
37 typedef struct ioat_rs_s {
38 /*
39 * Bounds of resource allocation. We will start allocating at rs_min
40 * and rollover at rs_max+1 (rs_max is included). e.g. for rs_min=0
41 * and rs_max=7, we will have 8 total resources which can be alloced.
42 */
43 uint_t rs_min;
44 uint_t rs_max;
45
46 /*
47 * rs_free points to an array of 64-bit values used to track resource
48 * allocation. rs_free_size is the free buffer size in bytes.
49 */
50 uint64_t *rs_free;
51 uint_t rs_free_size;
52
53 /*
54 * last tracks the last alloc'd resource. This allows us to do a round
55 * robin allocation.
56 */
57 uint_t rs_last;
58
59 kmutex_t rs_mutex;
60 } ioat_rs_t;
61
62
63 /*
64 * ioat_rs_init()
65 * Initialize the resource structure. This structure will be protected
66 * by a mutex at the iblock_cookie passed in. init() returns a handle to be
67 * used for the rest of the resource functions. This code is written assuming
68 * that min_val will be close to 0. Therefore, we will allocate the free
69 * buffer only taking max_val into account.
70 */
71 void
ioat_rs_init(ioat_state_t * state,uint_t min_val,uint_t max_val,ioat_rs_hdl_t * handle)72 ioat_rs_init(ioat_state_t *state, uint_t min_val, uint_t max_val,
73 ioat_rs_hdl_t *handle)
74 {
75 ioat_rs_t *rstruct;
76 uint_t array_size;
77 uint_t index;
78
79
80 ASSERT(handle != NULL);
81 ASSERT(min_val < max_val);
82
83 /* alloc space for resource structure */
84 rstruct = kmem_alloc(sizeof (ioat_rs_t), KM_SLEEP);
85
86 /*
87 * Test to see if the max value is 64-bit aligned. If so, we don't need
88 * to allocate an extra 64-bit word. alloc space for free buffer
89 * (8 bytes per uint64_t).
90 */
91 if ((max_val & 0x3F) == 0) {
92 rstruct->rs_free_size = (max_val >> 6) * 8;
93 } else {
94 rstruct->rs_free_size = ((max_val >> 6) + 1) * 8;
95 }
96 rstruct->rs_free = kmem_alloc(rstruct->rs_free_size, KM_SLEEP);
97
98 /* Initialize resource structure */
99 rstruct->rs_min = min_val;
100 rstruct->rs_last = min_val;
101 rstruct->rs_max = max_val;
102 mutex_init(&rstruct->rs_mutex, NULL, MUTEX_DRIVER,
103 state->is_iblock_cookie);
104
105 /* Mark all resources as free */
106 array_size = rstruct->rs_free_size >> 3;
107 for (index = 0; index < array_size; index++) {
108 rstruct->rs_free[index] = (uint64_t)0xFFFFFFFFFFFFFFFF;
109 }
110
111 /* setup handle which is returned from this function */
112 *handle = rstruct;
113 }
114
115
116 /*
117 * ioat_rs_fini()
118 * Frees up the space allocated in init(). Notice that a pointer to the
119 * handle is used for the parameter. fini() will set the handle to NULL
120 * before returning.
121 */
122 void
ioat_rs_fini(ioat_rs_hdl_t * handle)123 ioat_rs_fini(ioat_rs_hdl_t *handle)
124 {
125 ioat_rs_t *rstruct;
126
127
128 ASSERT(handle != NULL);
129
130 rstruct = (ioat_rs_t *)*handle;
131
132 mutex_destroy(&rstruct->rs_mutex);
133 kmem_free(rstruct->rs_free, rstruct->rs_free_size);
134 kmem_free(rstruct, sizeof (ioat_rs_t));
135
136 /* set handle to null. This helps catch bugs. */
137 *handle = NULL;
138 }
139
140
141 /*
142 * ioat_rs_alloc()
143 * alloc a resource. If alloc fails, we are out of resources.
144 */
145 int
ioat_rs_alloc(ioat_rs_hdl_t handle,uint_t * resource)146 ioat_rs_alloc(ioat_rs_hdl_t handle, uint_t *resource)
147 {
148 ioat_rs_t *rstruct;
149 uint_t array_idx;
150 uint64_t free;
151 uint_t index;
152 uint_t last;
153 uint_t min;
154 uint_t max;
155
156
157 ASSERT(handle != NULL);
158 ASSERT(resource != NULL);
159
160 rstruct = (ioat_rs_t *)handle;
161
162 mutex_enter(&rstruct->rs_mutex);
163 min = rstruct->rs_min;
164 max = rstruct->rs_max;
165
166 /*
167 * Find a free resource. This will return out of the loop once it finds
168 * a free resource. There are a total of 'max'-'min'+1 resources.
169 * Performs a round robin allocation.
170 */
171 for (index = min; index <= max; index++) {
172
173 array_idx = rstruct->rs_last >> 6;
174 free = rstruct->rs_free[array_idx];
175 last = rstruct->rs_last & 0x3F;
176
177 /* if the next resource to check is free */
178 if ((free & ((uint64_t)1 << last)) != 0) {
179 /* we are using this resource */
180 *resource = rstruct->rs_last;
181
182 /* take it out of the free list */
183 rstruct->rs_free[array_idx] &= ~((uint64_t)1 << last);
184
185 /*
186 * increment the last count so we start checking the
187 * next resource on the next alloc(). Note the rollover
188 * at 'max'+1.
189 */
190 rstruct->rs_last++;
191 if (rstruct->rs_last > max) {
192 rstruct->rs_last = rstruct->rs_min;
193 }
194
195 /* unlock the resource structure */
196 mutex_exit(&rstruct->rs_mutex);
197
198 return (DDI_SUCCESS);
199 }
200
201 /*
202 * This resource is not free, lets go to the next one. Note the
203 * rollover at 'max'.
204 */
205 rstruct->rs_last++;
206 if (rstruct->rs_last > max) {
207 rstruct->rs_last = rstruct->rs_min;
208 }
209 }
210
211 mutex_exit(&rstruct->rs_mutex);
212
213 return (DDI_FAILURE);
214 }
215
216
217 /*
218 * ioat_rs_free()
219 * Free the previously alloc'd resource. Once a resource has been free'd,
220 * it can be used again when alloc is called.
221 */
222 void
ioat_rs_free(ioat_rs_hdl_t handle,uint_t resource)223 ioat_rs_free(ioat_rs_hdl_t handle, uint_t resource)
224 {
225 ioat_rs_t *rstruct;
226 uint_t array_idx;
227 uint_t offset;
228
229
230 ASSERT(handle != NULL);
231
232 rstruct = (ioat_rs_t *)handle;
233 ASSERT(resource >= rstruct->rs_min);
234 ASSERT(resource <= rstruct->rs_max);
235
236 mutex_enter(&rstruct->rs_mutex);
237
238 /* Put the resource back in the free list */
239 array_idx = resource >> 6;
240 offset = resource & 0x3F;
241 rstruct->rs_free[array_idx] |= ((uint64_t)1 << offset);
242
243 mutex_exit(&rstruct->rs_mutex);
244 }
245