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1// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
2/*
3 * Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA
4 *
5 * PTP clock driver for VMware precision clock virtual device.
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/acpi.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/ptp_clock_kernel.h>
15#include <asm/hypervisor.h>
16#include <asm/vmware.h>
17
18#define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
19#define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
20
21static struct ptp_clock *ptp_vmw_clock;
22
23
24static int ptp_vmw_pclk_read(u64 *ns)
25{
26 u32 ret, nsec_hi, nsec_lo;
27
28 ret = vmware_hypercall3(VMWARE_CMD_PCLK_GETTIME, 0,
29 &nsec_hi, &nsec_lo);
30 if (ret == 0)
31 *ns = ((u64)nsec_hi << 32) | nsec_lo;
32 return ret;
33}
34
35/*
36 * PTP clock ops.
37 */
38
39static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta)
40{
41 return -EOPNOTSUPP;
42}
43
44static int ptp_vmw_adjfine(struct ptp_clock_info *info, long delta)
45{
46 return -EOPNOTSUPP;
47}
48
49static int ptp_vmw_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
50{
51 u64 ns;
52
53 if (ptp_vmw_pclk_read(&ns) != 0)
54 return -EIO;
55 *ts = ns_to_timespec64(ns);
56 return 0;
57}
58
59static int ptp_vmw_settime(struct ptp_clock_info *info,
60 const struct timespec64 *ts)
61{
62 return -EOPNOTSUPP;
63}
64
65static int ptp_vmw_enable(struct ptp_clock_info *info,
66 struct ptp_clock_request *request, int on)
67{
68 return -EOPNOTSUPP;
69}
70
71static struct ptp_clock_info ptp_vmw_clock_info = {
72 .owner = THIS_MODULE,
73 .name = "ptp_vmw",
74 .max_adj = 0,
75 .adjtime = ptp_vmw_adjtime,
76 .adjfine = ptp_vmw_adjfine,
77 .gettime64 = ptp_vmw_gettime,
78 .settime64 = ptp_vmw_settime,
79 .enable = ptp_vmw_enable,
80};
81
82/*
83 * ACPI driver ops for VMware "precision clock" virtual device.
84 */
85
86static int ptp_vmw_acpi_probe(struct platform_device *pdev)
87{
88 ptp_vmw_clock = ptp_clock_register(&ptp_vmw_clock_info, NULL);
89 if (IS_ERR(ptp_vmw_clock)) {
90 pr_err("failed to register ptp clock\n");
91 return PTR_ERR(ptp_vmw_clock);
92 }
93 return 0;
94}
95
96static void ptp_vmw_acpi_remove(struct platform_device *pdev)
97{
98 ptp_clock_unregister(ptp_vmw_clock);
99}
100
101static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = {
102 { "VMW0005", 0 },
103 { "", 0 },
104};
105
106MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids);
107
108static struct platform_driver ptp_vmw_acpi_driver = {
109 .probe = ptp_vmw_acpi_probe,
110 .remove = ptp_vmw_acpi_remove,
111 .driver = {
112 .name = "ptp_vmw_acpi",
113 .acpi_match_table = ptp_vmw_acpi_device_ids,
114 },
115};
116
117static int __init ptp_vmw_init(void)
118{
119 if (x86_hyper_type != X86_HYPER_VMWARE)
120 return -1;
121 return platform_driver_register(&ptp_vmw_acpi_driver);
122}
123
124static void __exit ptp_vmw_exit(void)
125{
126 platform_driver_unregister(&ptp_vmw_acpi_driver);
127}
128
129module_init(ptp_vmw_init);
130module_exit(ptp_vmw_exit);
131
132MODULE_DESCRIPTION("VMware virtual PTP clock driver");
133MODULE_AUTHOR("VMware, Inc.");
134MODULE_LICENSE("Dual BSD/GPL");