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>
23 #include <asm/machdep.h>
26 #define N_ASYNC_COMPLETIONS 64
28 static DECLARE_BITMAP(opal_async_complete_map, N_ASYNC_COMPLETIONS) = {~0UL};
29 static DECLARE_BITMAP(opal_async_token_map, N_ASYNC_COMPLETIONS);
30 static DECLARE_WAIT_QUEUE_HEAD(opal_async_wait);
31 static DEFINE_SPINLOCK(opal_async_comp_lock);
32 static struct semaphore opal_async_sem;
33 static struct opal_msg *opal_async_responses;
34 static unsigned int opal_max_async_tokens;
36 int __opal_async_get_token(void)
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) {
48 if (__test_and_set_bit(token, opal_async_token_map)) {
53 __clear_bit(token, opal_async_complete_map);
56 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
60 int opal_async_get_token_interruptible(void)
64 /* Wait until a token is available */
65 if (down_interruptible(&opal_async_sem))
68 token = __opal_async_get_token();
74 EXPORT_SYMBOL_GPL(opal_async_get_token_interruptible);
76 int __opal_async_release_token(int token)
80 if (token < 0 || token >= opal_max_async_tokens) {
81 pr_err("%s: Passed token is out of range, token %d\n",
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);
94 int opal_async_release_token(int token)
98 ret = __opal_async_release_token(token);
106 EXPORT_SYMBOL_GPL(opal_async_release_token);
108 int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
110 if (token >= opal_max_async_tokens) {
111 pr_err("%s: Invalid token passed\n", __func__);
116 pr_err("%s: Invalid message pointer passed\n", __func__);
120 /* Wakeup the poller before we wait for events to speed things
121 * up on platforms or simulators where the interrupts aren't
125 wait_event(opal_async_wait, test_bit(token, opal_async_complete_map));
126 memcpy(msg, &opal_async_responses[token], sizeof(*msg));
130 EXPORT_SYMBOL_GPL(opal_async_wait_response);
132 static int opal_async_comp_event(struct notifier_block *nb,
133 unsigned long msg_type, void *msg)
135 struct opal_msg *comp_msg = msg;
139 if (msg_type != OPAL_MSG_ASYNC_COMP)
142 token = be64_to_cpu(comp_msg->params[0]);
143 memcpy(&opal_async_responses[token], comp_msg, sizeof(*comp_msg));
144 spin_lock_irqsave(&opal_async_comp_lock, flags);
145 __set_bit(token, opal_async_complete_map);
146 spin_unlock_irqrestore(&opal_async_comp_lock, flags);
148 wake_up(&opal_async_wait);
153 static struct notifier_block opal_async_comp_nb = {
154 .notifier_call = opal_async_comp_event,
159 int __init opal_async_comp_init(void)
161 struct device_node *opal_node;
165 opal_node = of_find_node_by_path("/ibm,opal");
167 pr_err("%s: Opal node not found\n", __func__);
172 async = of_get_property(opal_node, "opal-msg-async-num", NULL);
174 pr_err("%s: %s has no opal-msg-async-num\n",
175 __func__, opal_node->full_name);
180 opal_max_async_tokens = be32_to_cpup(async);
181 if (opal_max_async_tokens > N_ASYNC_COMPLETIONS)
182 opal_max_async_tokens = N_ASYNC_COMPLETIONS;
184 err = opal_message_notifier_register(OPAL_MSG_ASYNC_COMP,
185 &opal_async_comp_nb);
187 pr_err("%s: Can't register OPAL event notifier (%d)\n",
192 opal_async_responses = kzalloc(
193 sizeof(*opal_async_responses) * opal_max_async_tokens,
195 if (!opal_async_responses) {
196 pr_err("%s: Out of memory, failed to do asynchronous "
197 "completion init\n", __func__);
202 /* Initialize to 1 less than the maximum tokens available, as we may
203 * require to pop one during emergency through synchronous call to
204 * __opal_async_get_token()
206 sema_init(&opal_async_sem, opal_max_async_tokens - 1);
209 of_node_put(opal_node);