summaryrefslogtreecommitdiffstats
path: root/drivers/ptp/ptp_kvm_common.c
blob: 2418977989beb420a9587d9c013e61b950d09b85 (plain)
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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Virtual PTP 1588 clock for use with KVM guests
 *
 * Copyright (C) 2017 Red Hat Inc.
 */
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/ptp_kvm.h>
#include <uapi/linux/kvm_para.h>
#include <asm/kvm_para.h>
#include <uapi/asm/kvm_para.h>

#include <linux/ptp_clock_kernel.h>

struct kvm_ptp_clock {
	struct ptp_clock *ptp_clock;
	struct ptp_clock_info caps;
};

static DEFINE_SPINLOCK(kvm_ptp_lock);

static int ptp_kvm_get_time_fn(ktime_t *device_time,
			       struct system_counterval_t *system_counter,
			       void *ctx)
{
	long ret;
	u64 cycle;
	struct timespec64 tspec;
	struct clocksource *cs;

	spin_lock(&kvm_ptp_lock);

	preempt_disable_notrace();
	ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs);
	if (ret) {
		spin_unlock(&kvm_ptp_lock);
		preempt_enable_notrace();
		return ret;
	}

	preempt_enable_notrace();

	system_counter->cycles = cycle;
	system_counter->cs = cs;

	*device_time = timespec64_to_ktime(tspec);

	spin_unlock(&kvm_ptp_lock);

	return 0;
}

static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
				  struct system_device_crosststamp *xtstamp)
{
	return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
					     NULL, xtstamp);
}

/*
 * PTP clock operations
 */

static int ptp_kvm_adjfine(struct ptp_clock_info *ptp, long delta)
{
	return -EOPNOTSUPP;
}

static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
	return -EOPNOTSUPP;
}

static int ptp_kvm_settime(struct ptp_clock_info *ptp,
			   const struct timespec64 *ts)
{
	return -EOPNOTSUPP;
}

static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
	long ret;
	struct timespec64 tspec;

	spin_lock(&kvm_ptp_lock);

	ret = kvm_arch_ptp_get_clock(&tspec);
	if (ret) {
		spin_unlock(&kvm_ptp_lock);
		return ret;
	}

	spin_unlock(&kvm_ptp_lock);

	memcpy(ts, &tspec, sizeof(struct timespec64));

	return 0;
}

static int ptp_kvm_enable(struct ptp_clock_info *ptp,
			  struct ptp_clock_request *rq, int on)
{
	return -EOPNOTSUPP;
}

static const struct ptp_clock_info ptp_kvm_caps = {
	.owner		= THIS_MODULE,
	.name		= "KVM virtual PTP",
	.max_adj	= 0,
	.n_ext_ts	= 0,
	.n_pins		= 0,
	.pps		= 0,
	.adjfine	= ptp_kvm_adjfine,
	.adjtime	= ptp_kvm_adjtime,
	.gettime64	= ptp_kvm_gettime,
	.settime64	= ptp_kvm_settime,
	.enable		= ptp_kvm_enable,
	.getcrosststamp = ptp_kvm_getcrosststamp,
};

/* module operations */

static struct kvm_ptp_clock kvm_ptp_clock;

static void __exit ptp_kvm_exit(void)
{
	ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
	kvm_arch_ptp_exit();
}

static int __init ptp_kvm_init(void)
{
	long ret;

	ret = kvm_arch_ptp_init();
	if (ret) {
		if (ret != -EOPNOTSUPP)
			pr_err("fail to initialize ptp_kvm");
		return ret;
	}

	kvm_ptp_clock.caps = ptp_kvm_caps;

	kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);

	return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock);
}

module_init(ptp_kvm_init);
module_exit(ptp_kvm_exit);

MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
MODULE_LICENSE("GPL");