1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/*
* PowerNV OPAL asynchronous completion interfaces
*
* Copyright 2013 IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#undef DEBUG
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/semaphore.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/gfp.h>
#include <linux/of.h>
#include <asm/opal.h>
#define N_ASYNC_COMPLETIONS 64
static DECLARE_BITMAP(opal_async_complete_map, N_ASYNC_COMPLETIONS) = {~0UL};
static DECLARE_BITMAP(opal_async_token_map, N_ASYNC_COMPLETIONS);
static DECLARE_WAIT_QUEUE_HEAD(opal_async_wait);
static DEFINE_SPINLOCK(opal_async_comp_lock);
static struct semaphore opal_async_sem;
static struct opal_msg *opal_async_responses;
static unsigned int opal_max_async_tokens;
int __opal_async_get_token(void)
{
unsigned long flags;
int token;
spin_lock_irqsave(&opal_async_comp_lock, flags);
token = find_first_bit(opal_async_complete_map, opal_max_async_tokens);
if (token >= opal_max_async_tokens) {
token = -EBUSY;
goto out;
}
if (__test_and_set_bit(token, opal_async_token_map)) {
token = -EBUSY;
goto out;
}
__clear_bit(token, opal_async_complete_map);
out:
spin_unlock_irqrestore(&opal_async_comp_lock, flags);
return token;
}
int opal_async_get_token_interruptible(void)
{
int token;
/* Wait until a token is available */
if (down_interruptible(&opal_async_sem))
return -ERESTARTSYS;
token = __opal_async_get_token();
if (token < 0)
up(&opal_async_sem);
return token;
}
int __opal_async_release_token(int token)
{
unsigned long flags;
if (token < 0 || token >= opal_max_async_tokens) {
pr_err("%s: Passed token is out of range, token %d\n",
__func__, token);
return -EINVAL;
}
spin_lock_irqsave(&opal_async_comp_lock, flags);
__set_bit(token, opal_async_complete_map);
__clear_bit(token, opal_async_token_map);
spin_unlock_irqrestore(&opal_async_comp_lock, flags);
return 0;
}
int opal_async_release_token(int token)
{
int ret;
ret = __opal_async_release_token(token);
if (ret)
return ret;
up(&opal_async_sem);
return 0;
}
int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
{
if (token >= opal_max_async_tokens) {
pr_err("%s: Invalid token passed\n", __func__);
return -EINVAL;
}
if (!msg) {
pr_err("%s: Invalid message pointer passed\n", __func__);
return -EINVAL;
}
wait_event(opal_async_wait, test_bit(token, opal_async_complete_map));
memcpy(msg, &opal_async_responses[token], sizeof(*msg));
return 0;
}
static int opal_async_comp_event(struct notifier_block *nb,
unsigned long msg_type, void *msg)
{
struct opal_msg *comp_msg = msg;
unsigned long flags;
uint64_t token;
if (msg_type != OPAL_MSG_ASYNC_COMP)
return 0;
token = be64_to_cpu(comp_msg->params[0]);
memcpy(&opal_async_responses[token], comp_msg, sizeof(*comp_msg));
spin_lock_irqsave(&opal_async_comp_lock, flags);
__set_bit(token, opal_async_complete_map);
spin_unlock_irqrestore(&opal_async_comp_lock, flags);
wake_up(&opal_async_wait);
return 0;
}
static struct notifier_block opal_async_comp_nb = {
.notifier_call = opal_async_comp_event,
.next = NULL,
.priority = 0,
};
static int __init opal_async_comp_init(void)
{
struct device_node *opal_node;
const __be32 *async;
int err;
opal_node = of_find_node_by_path("/ibm,opal");
if (!opal_node) {
pr_err("%s: Opal node not found\n", __func__);
err = -ENOENT;
goto out;
}
async = of_get_property(opal_node, "opal-msg-async-num", NULL);
if (!async) {
pr_err("%s: %s has no opal-msg-async-num\n",
__func__, opal_node->full_name);
err = -ENOENT;
goto out_opal_node;
}
opal_max_async_tokens = be32_to_cpup(async);
if (opal_max_async_tokens > N_ASYNC_COMPLETIONS)
opal_max_async_tokens = N_ASYNC_COMPLETIONS;
err = opal_message_notifier_register(OPAL_MSG_ASYNC_COMP,
&opal_async_comp_nb);
if (err) {
pr_err("%s: Can't register OPAL event notifier (%d)\n",
__func__, err);
goto out_opal_node;
}
opal_async_responses = kzalloc(
sizeof(*opal_async_responses) * opal_max_async_tokens,
GFP_KERNEL);
if (!opal_async_responses) {
pr_err("%s: Out of memory, failed to do asynchronous "
"completion init\n", __func__);
err = -ENOMEM;
goto out_opal_node;
}
/* Initialize to 1 less than the maximum tokens available, as we may
* require to pop one during emergency through synchronous call to
* __opal_async_get_token()
*/
sema_init(&opal_async_sem, opal_max_async_tokens - 1);
out_opal_node:
of_node_put(opal_node);
out:
return err;
}
subsys_initcall(opal_async_comp_init);
|
