1 /*-
2 * Copyright (C) 2019 Justin Hibbits
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
17 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
18 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
19 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
20 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
21 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
22 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25 #include <sys/param.h>
26 #include <sys/eventhandler.h>
27 #include <sys/malloc.h>
28 #include <sys/proc.h>
29 #include <sys/vmem.h>
30
31 #include <vm/vm.h>
32 #include <vm/pmap.h>
33 #include "opal.h"
34
35 #include <machine/cpufunc.h>
36
37 /*
38 * Manage asynchronous tokens for the OPAL abstraction layer.
39 *
40 * Only a finite number of in-flight tokens are supported by OPAL, so we must be
41 * careful managing this. The basic design uses the vmem subsystem as a general
42 * purpose allocator, with wrappers to manage expected behaviors and
43 * requirements.
44 */
45 static vmem_t *async_token_pool;
46
47 static void opal_handle_async_completion(void *, struct opal_msg *);
48
49 struct async_completion {
50 volatile uint64_t completed;
51 struct opal_msg msg;
52 };
53
54 struct async_completion *completions;
55
56 /* Setup the token pool. */
57 int
opal_init_async_tokens(int count)58 opal_init_async_tokens(int count)
59 {
60 /* Only allow one initialization */
61 if (async_token_pool != NULL)
62 return (EINVAL);
63
64 async_token_pool = vmem_create("OPAL Async", 0, count, 1, 1,
65 M_WAITOK | M_FIRSTFIT);
66 completions = malloc(count * sizeof(struct async_completion),
67 M_DEVBUF, M_WAITOK | M_ZERO);
68
69 EVENTHANDLER_REGISTER(OPAL_ASYNC_COMP, opal_handle_async_completion,
70 NULL, EVENTHANDLER_PRI_ANY);
71
72 return (0);
73 }
74
75 int
opal_alloc_async_token(void)76 opal_alloc_async_token(void)
77 {
78 vmem_addr_t token;
79
80 vmem_alloc(async_token_pool, 1, M_FIRSTFIT | M_WAITOK, &token);
81 completions[token].completed = false;
82
83 return (token);
84 }
85
86 void
opal_free_async_token(int token)87 opal_free_async_token(int token)
88 {
89
90 vmem_free(async_token_pool, token, 1);
91 }
92
93 /*
94 * Wait for the operation watched by the token to complete. Return the result
95 * of the operation, error if it returns early.
96 */
97 int
opal_wait_completion(void * buf,uint64_t size,int token)98 opal_wait_completion(void *buf, uint64_t size, int token)
99 {
100 int err;
101
102 do {
103 err = opal_call(OPAL_CHECK_ASYNC_COMPLETION,
104 vtophys(buf), size, token);
105 if (err == OPAL_BUSY) {
106 if (completions[token].completed) {
107 atomic_thread_fence_acq();
108 memcpy(buf, &completions[token].msg, size);
109 return (OPAL_SUCCESS);
110 }
111 }
112 DELAY(100);
113 } while (err == OPAL_BUSY);
114
115 return (err);
116 }
117
opal_handle_async_completion(void * arg,struct opal_msg * msg)118 static void opal_handle_async_completion(void *arg, struct opal_msg *msg)
119 {
120 int token;
121
122 token = msg->params[0];
123 memcpy(&completions[token].msg, msg, sizeof(*msg));
124 atomic_thread_fence_rel();
125 completions[token].completed = true;
126 }
127