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12#undef DEBUG
13
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/slab.h>
17#include <linux/sched.h>
18#include <linux/semaphore.h>
19#include <linux/spinlock.h>
20#include <linux/wait.h>
21#include <linux/gfp.h>
22#include <linux/of.h>
23#include <asm/machdep.h>
24#include <asm/opal.h>
25
26#define N_ASYNC_COMPLETIONS 64
27
28static DECLARE_BITMAP(opal_async_complete_map, N_ASYNC_COMPLETIONS) = {~0UL};
29static DECLARE_BITMAP(opal_async_token_map, N_ASYNC_COMPLETIONS);
30static DECLARE_WAIT_QUEUE_HEAD(opal_async_wait);
31static DEFINE_SPINLOCK(opal_async_comp_lock);
32static struct semaphore opal_async_sem;
33static struct opal_msg *opal_async_responses;
34static unsigned int opal_max_async_tokens;
35
36int __opal_async_get_token(void)
37{
38 unsigned long flags;
39 int token;
40
41 spin_lock_irqsave(&opal_async_comp_lock, flags);
42 token = find_first_bit(opal_async_complete_map, opal_max_async_tokens);
43 if (token >= opal_max_async_tokens) {
44 token = -EBUSY;
45 goto out;
46 }
47
48 if (__test_and_set_bit(token, opal_async_token_map)) {
49 token = -EBUSY;
50 goto out;
51 }
52
53 __clear_bit(token, opal_async_complete_map);
54
55out:
56 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
57 return token;
58}
59
60int opal_async_get_token_interruptible(void)
61{
62 int token;
63
64
65 if (down_interruptible(&opal_async_sem))
66 return -ERESTARTSYS;
67
68 token = __opal_async_get_token();
69 if (token < 0)
70 up(&opal_async_sem);
71
72 return token;
73}
74EXPORT_SYMBOL_GPL(opal_async_get_token_interruptible);
75
76int __opal_async_release_token(int token)
77{
78 unsigned long flags;
79
80 if (token < 0 || token >= opal_max_async_tokens) {
81 pr_err("%s: Passed token is out of range, token %d\n",
82 __func__, token);
83 return -EINVAL;
84 }
85
86 spin_lock_irqsave(&opal_async_comp_lock, flags);
87 __set_bit(token, opal_async_complete_map);
88 __clear_bit(token, opal_async_token_map);
89 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
90
91 return 0;
92}
93
94int opal_async_release_token(int token)
95{
96 int ret;
97
98 ret = __opal_async_release_token(token);
99 if (ret)
100 return ret;
101
102 up(&opal_async_sem);
103
104 return 0;
105}
106EXPORT_SYMBOL_GPL(opal_async_release_token);
107
108int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
109{
110 if (token >= opal_max_async_tokens) {
111 pr_err("%s: Invalid token passed\n", __func__);
112 return -EINVAL;
113 }
114
115 if (!msg) {
116 pr_err("%s: Invalid message pointer passed\n", __func__);
117 return -EINVAL;
118 }
119
120 wait_event(opal_async_wait, test_bit(token, opal_async_complete_map));
121 memcpy(msg, &opal_async_responses[token], sizeof(*msg));
122
123 return 0;
124}
125EXPORT_SYMBOL_GPL(opal_async_wait_response);
126
127static int opal_async_comp_event(struct notifier_block *nb,
128 unsigned long msg_type, void *msg)
129{
130 struct opal_msg *comp_msg = msg;
131 unsigned long flags;
132 uint64_t token;
133
134 if (msg_type != OPAL_MSG_ASYNC_COMP)
135 return 0;
136
137 token = be64_to_cpu(comp_msg->params[0]);
138 memcpy(&opal_async_responses[token], comp_msg, sizeof(*comp_msg));
139 spin_lock_irqsave(&opal_async_comp_lock, flags);
140 __set_bit(token, opal_async_complete_map);
141 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
142
143 wake_up(&opal_async_wait);
144
145 return 0;
146}
147
148static struct notifier_block opal_async_comp_nb = {
149 .notifier_call = opal_async_comp_event,
150 .next = NULL,
151 .priority = 0,
152};
153
154static int __init opal_async_comp_init(void)
155{
156 struct device_node *opal_node;
157 const __be32 *async;
158 int err;
159
160 opal_node = of_find_node_by_path("/ibm,opal");
161 if (!opal_node) {
162 pr_err("%s: Opal node not found\n", __func__);
163 err = -ENOENT;
164 goto out;
165 }
166
167 async = of_get_property(opal_node, "opal-msg-async-num", NULL);
168 if (!async) {
169 pr_err("%s: %s has no opal-msg-async-num\n",
170 __func__, opal_node->full_name);
171 err = -ENOENT;
172 goto out_opal_node;
173 }
174
175 opal_max_async_tokens = be32_to_cpup(async);
176 if (opal_max_async_tokens > N_ASYNC_COMPLETIONS)
177 opal_max_async_tokens = N_ASYNC_COMPLETIONS;
178
179 err = opal_message_notifier_register(OPAL_MSG_ASYNC_COMP,
180 &opal_async_comp_nb);
181 if (err) {
182 pr_err("%s: Can't register OPAL event notifier (%d)\n",
183 __func__, err);
184 goto out_opal_node;
185 }
186
187 opal_async_responses = kzalloc(
188 sizeof(*opal_async_responses) * opal_max_async_tokens,
189 GFP_KERNEL);
190 if (!opal_async_responses) {
191 pr_err("%s: Out of memory, failed to do asynchronous "
192 "completion init\n", __func__);
193 err = -ENOMEM;
194 goto out_opal_node;
195 }
196
197
198
199
200
201 sema_init(&opal_async_sem, opal_max_async_tokens - 1);
202
203out_opal_node:
204 of_node_put(opal_node);
205out:
206 return err;
207}
208machine_subsys_initcall(powernv, opal_async_comp_init);
209
