// SPDX-License-Identifier: GPL-2.0
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#include <linux/init.h>
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#include <linux/kthread.h>
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#include <linux/hrtimer.h>
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#include <linux/fs.h>
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#include <linux/debugfs.h>
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#include <linux/export.h>
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#include <linux/spinlock.h>
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#include <asm/debug.h>
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static int ss_get(void *data, u64 *val)
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{
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ktime_t start, finish;
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int loops;
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int cont;
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DEFINE_RAW_SPINLOCK(ss_spin);
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loops = 1000000;
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cont = 1;
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start = ktime_get();
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while (cont) {
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raw_spin_lock(&ss_spin);
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loops--;
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if (loops == 0)
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cont = 0;
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raw_spin_unlock(&ss_spin);
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}
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finish = ktime_get();
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*val = ktime_us_delta(finish, start);
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return 0;
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}
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DEFINE_SIMPLE_ATTRIBUTE(fops_ss, ss_get, NULL, "%llu\n");
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struct spin_multi_state {
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raw_spinlock_t lock;
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atomic_t start_wait;
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atomic_t enter_wait;
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atomic_t exit_wait;
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int loops;
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};
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struct spin_multi_per_thread {
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struct spin_multi_state *state;
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ktime_t start;
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};
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static int multi_other(void *data)
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{
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int loops;
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int cont;
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struct spin_multi_per_thread *pt = data;
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struct spin_multi_state *s = pt->state;
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loops = s->loops;
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cont = 1;
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atomic_dec(&s->enter_wait);
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while (atomic_read(&s->enter_wait))
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; /* spin */
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pt->start = ktime_get();
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atomic_dec(&s->start_wait);
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while (atomic_read(&s->start_wait))
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; /* spin */
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while (cont) {
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raw_spin_lock(&s->lock);
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loops--;
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if (loops == 0)
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cont = 0;
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raw_spin_unlock(&s->lock);
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}
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atomic_dec(&s->exit_wait);
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while (atomic_read(&s->exit_wait))
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; /* spin */
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return 0;
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}
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static int multi_get(void *data, u64 *val)
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{
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ktime_t finish;
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struct spin_multi_state ms;
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struct spin_multi_per_thread t1, t2;
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ms.lock = __RAW_SPIN_LOCK_UNLOCKED("multi_get");
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ms.loops = 1000000;
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atomic_set(&ms.start_wait, 2);
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atomic_set(&ms.enter_wait, 2);
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atomic_set(&ms.exit_wait, 2);
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t1.state = &ms;
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t2.state = &ms;
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kthread_run(multi_other, &t2, "multi_get");
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multi_other(&t1);
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finish = ktime_get();
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*val = ktime_us_delta(finish, t1.start);
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return 0;
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}
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DEFINE_SIMPLE_ATTRIBUTE(fops_multi, multi_get, NULL, "%llu\n");
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static int __init spinlock_test(void)
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{
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debugfs_create_file("spin_single", S_IRUGO, mips_debugfs_dir, NULL,
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&fops_ss);
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debugfs_create_file("spin_multi", S_IRUGO, mips_debugfs_dir, NULL,
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&fops_multi);
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return 0;
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}
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device_initcall(spinlock_test);
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