2 * PowerNV OPAL asynchronous completion interfaces
4 * Copyright 2013 IBM Corp.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
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>
25 #define N_ASYNC_COMPLETIONS 64
27 static DECLARE_BITMAP(opal_async_complete_map, N_ASYNC_COMPLETIONS) = {~0UL};
28 static DECLARE_BITMAP(opal_async_token_map, N_ASYNC_COMPLETIONS);
29 static DECLARE_WAIT_QUEUE_HEAD(opal_async_wait);
30 static DEFINE_SPINLOCK(opal_async_comp_lock);
31 static struct semaphore opal_async_sem;
32 static struct opal_msg *opal_async_responses;
33 static unsigned int opal_max_async_tokens;
35 int __opal_async_get_token(void)
40 spin_lock_irqsave(&opal_async_comp_lock, flags);
41 token = find_first_bit(opal_async_complete_map, opal_max_async_tokens);
42 if (token >= opal_max_async_tokens) {
47 if (__test_and_set_bit(token, opal_async_token_map)) {
52 __clear_bit(token, opal_async_complete_map);
55 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
59 int opal_async_get_token_interruptible(void)
63 /* Wait until a token is available */
64 if (down_interruptible(&opal_async_sem))
67 token = __opal_async_get_token();
74 int __opal_async_release_token(int token)
78 if (token < 0 || token >= opal_max_async_tokens) {
79 pr_err("%s: Passed token is out of range, token %d\n",
84 spin_lock_irqsave(&opal_async_comp_lock, flags);
85 __set_bit(token, opal_async_complete_map);
86 __clear_bit(token, opal_async_token_map);
87 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
92 int opal_async_release_token(int token)
96 ret = __opal_async_release_token(token);
105 int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
107 if (token >= opal_max_async_tokens) {
108 pr_err("%s: Invalid token passed\n", __func__);
113 pr_err("%s: Invalid message pointer passed\n", __func__);
117 wait_event(opal_async_wait, test_bit(token, opal_async_complete_map));
118 memcpy(msg, &opal_async_responses[token], sizeof(*msg));
123 static int opal_async_comp_event(struct notifier_block *nb,
124 unsigned long msg_type, void *msg)
126 struct opal_msg *comp_msg = msg;
130 if (msg_type != OPAL_MSG_ASYNC_COMP)
133 token = be64_to_cpu(comp_msg->params[0]);
134 memcpy(&opal_async_responses[token], comp_msg, sizeof(*comp_msg));
135 spin_lock_irqsave(&opal_async_comp_lock, flags);
136 __set_bit(token, opal_async_complete_map);
137 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
139 wake_up(&opal_async_wait);
144 static struct notifier_block opal_async_comp_nb = {
145 .notifier_call = opal_async_comp_event,
150 static int __init opal_async_comp_init(void)
152 struct device_node *opal_node;
156 opal_node = of_find_node_by_path("/ibm,opal");
158 pr_err("%s: Opal node not found\n", __func__);
163 async = of_get_property(opal_node, "opal-msg-async-num", NULL);
165 pr_err("%s: %s has no opal-msg-async-num\n",
166 __func__, opal_node->full_name);
171 opal_max_async_tokens = be32_to_cpup(async);
172 if (opal_max_async_tokens > N_ASYNC_COMPLETIONS)
173 opal_max_async_tokens = N_ASYNC_COMPLETIONS;
175 err = opal_message_notifier_register(OPAL_MSG_ASYNC_COMP,
176 &opal_async_comp_nb);
178 pr_err("%s: Can't register OPAL event notifier (%d)\n",
183 opal_async_responses = kzalloc(
184 sizeof(*opal_async_responses) * opal_max_async_tokens,
186 if (!opal_async_responses) {
187 pr_err("%s: Out of memory, failed to do asynchronous "
188 "completion init\n", __func__);
193 /* Initialize to 1 less than the maximum tokens available, as we may
194 * require to pop one during emergency through synchronous call to
195 * __opal_async_get_token()
197 sema_init(&opal_async_sem, opal_max_async_tokens - 1);
200 of_node_put(opal_node);
204 subsys_initcall(opal_async_comp_init);