1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Virtual PTP 1588 clock for use with KVM guests
4 *
5 * Copyright (C) 2017 Red Hat Inc.
6 */
7#include <linux/device.h>
8#include <linux/err.h>
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/module.h>
13#include <linux/ptp_kvm.h>
14#include <uapi/linux/kvm_para.h>
15#include <asm/kvm_para.h>
16#include <uapi/asm/kvm_para.h>
17
18#include <linux/ptp_clock_kernel.h>
19
20struct kvm_ptp_clock {
21	struct ptp_clock *ptp_clock;
22	struct ptp_clock_info caps;
23};
24
25static DEFINE_SPINLOCK(kvm_ptp_lock);
26
27static int ptp_kvm_get_time_fn(ktime_t *device_time,
28			       struct system_counterval_t *system_counter,
29			       void *ctx)
30{
31	enum clocksource_ids cs_id;
32	struct timespec64 tspec;
33	u64 cycle;
34	int ret;
35
36	spin_lock(&kvm_ptp_lock);
37
38	preempt_disable_notrace();
39	ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs_id);
40	if (ret) {
41		spin_unlock(&kvm_ptp_lock);
42		preempt_enable_notrace();
43		return ret;
44	}
45
46	preempt_enable_notrace();
47
48	system_counter->cycles = cycle;
49	system_counter->cs_id = cs_id;
50
51	*device_time = timespec64_to_ktime(tspec);
52
53	spin_unlock(&kvm_ptp_lock);
54
55	return 0;
56}
57
58static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
59				  struct system_device_crosststamp *xtstamp)
60{
61	return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
62					     NULL, xtstamp);
63}
64
65/*
66 * PTP clock operations
67 */
68
69static int ptp_kvm_adjfine(struct ptp_clock_info *ptp, long delta)
70{
71	return -EOPNOTSUPP;
72}
73
74static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
75{
76	return -EOPNOTSUPP;
77}
78
79static int ptp_kvm_settime(struct ptp_clock_info *ptp,
80			   const struct timespec64 *ts)
81{
82	return -EOPNOTSUPP;
83}
84
85static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
86{
87	long ret;
88	struct timespec64 tspec;
89
90	spin_lock(&kvm_ptp_lock);
91
92	ret = kvm_arch_ptp_get_clock(&tspec);
93	if (ret) {
94		spin_unlock(&kvm_ptp_lock);
95		return ret;
96	}
97
98	spin_unlock(&kvm_ptp_lock);
99
100	memcpy(ts, &tspec, sizeof(struct timespec64));
101
102	return 0;
103}
104
105static int ptp_kvm_enable(struct ptp_clock_info *ptp,
106			  struct ptp_clock_request *rq, int on)
107{
108	return -EOPNOTSUPP;
109}
110
111static const struct ptp_clock_info ptp_kvm_caps = {
112	.owner		= THIS_MODULE,
113	.name		= "KVM virtual PTP",
114	.max_adj	= 0,
115	.n_ext_ts	= 0,
116	.n_pins		= 0,
117	.pps		= 0,
118	.adjfine	= ptp_kvm_adjfine,
119	.adjtime	= ptp_kvm_adjtime,
120	.gettime64	= ptp_kvm_gettime,
121	.settime64	= ptp_kvm_settime,
122	.enable		= ptp_kvm_enable,
123	.getcrosststamp = ptp_kvm_getcrosststamp,
124};
125
126/* module operations */
127
128static struct kvm_ptp_clock kvm_ptp_clock;
129
130static void __exit ptp_kvm_exit(void)
131{
132	ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
133	kvm_arch_ptp_exit();
134}
135
136static int __init ptp_kvm_init(void)
137{
138	long ret;
139
140	ret = kvm_arch_ptp_init();
141	if (ret) {
142		if (ret != -EOPNOTSUPP)
143			pr_err("fail to initialize ptp_kvm");
144		return ret;
145	}
146
147	kvm_ptp_clock.caps = ptp_kvm_caps;
148
149	kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
150
151	return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock);
152}
153
154module_init(ptp_kvm_init);
155module_exit(ptp_kvm_exit);
156
157MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
158MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
159MODULE_LICENSE("GPL");
160