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/ptp_clock_kernel.h>
14 #include <asm/hypervisor.h>
15 #include <asm/vmware.h>
16
17 #define VMWARE_MAGIC 0x564D5868
18 #define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
19 #define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
20
21 static struct acpi_device *ptp_vmw_acpi_device;
22 static struct ptp_clock *ptp_vmw_clock;
23
24
ptp_vmw_pclk_read(u64 * ns)25 static int ptp_vmw_pclk_read(u64 *ns)
26 {
27 u32 ret, nsec_hi, nsec_lo, unused1, unused2, unused3;
28
29 asm volatile (VMWARE_HYPERCALL :
30 "=a"(ret), "=b"(nsec_hi), "=c"(nsec_lo), "=d"(unused1),
31 "=S"(unused2), "=D"(unused3) :
32 "a"(VMWARE_MAGIC), "b"(0),
33 "c"(VMWARE_CMD_PCLK_GETTIME), "d"(0) :
34 "memory");
35
36 if (ret == 0)
37 *ns = ((u64)nsec_hi << 32) | nsec_lo;
38 return ret;
39 }
40
41 /*
42 * PTP clock ops.
43 */
44
ptp_vmw_adjtime(struct ptp_clock_info * info,s64 delta)45 static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta)
46 {
47 return -EOPNOTSUPP;
48 }
49
ptp_vmw_adjfine(struct ptp_clock_info * info,long delta)50 static int ptp_vmw_adjfine(struct ptp_clock_info *info, long delta)
51 {
52 return -EOPNOTSUPP;
53 }
54
ptp_vmw_gettime(struct ptp_clock_info * info,struct timespec64 * ts)55 static int ptp_vmw_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
56 {
57 u64 ns;
58
59 if (ptp_vmw_pclk_read(&ns) != 0)
60 return -EIO;
61 *ts = ns_to_timespec64(ns);
62 return 0;
63 }
64
ptp_vmw_settime(struct ptp_clock_info * info,const struct timespec64 * ts)65 static int ptp_vmw_settime(struct ptp_clock_info *info,
66 const struct timespec64 *ts)
67 {
68 return -EOPNOTSUPP;
69 }
70
ptp_vmw_enable(struct ptp_clock_info * info,struct ptp_clock_request * request,int on)71 static int ptp_vmw_enable(struct ptp_clock_info *info,
72 struct ptp_clock_request *request, int on)
73 {
74 return -EOPNOTSUPP;
75 }
76
77 static struct ptp_clock_info ptp_vmw_clock_info = {
78 .owner = THIS_MODULE,
79 .name = "ptp_vmw",
80 .max_adj = 0,
81 .adjtime = ptp_vmw_adjtime,
82 .adjfine = ptp_vmw_adjfine,
83 .gettime64 = ptp_vmw_gettime,
84 .settime64 = ptp_vmw_settime,
85 .enable = ptp_vmw_enable,
86 };
87
88 /*
89 * ACPI driver ops for VMware "precision clock" virtual device.
90 */
91
ptp_vmw_acpi_add(struct acpi_device * device)92 static int ptp_vmw_acpi_add(struct acpi_device *device)
93 {
94 ptp_vmw_clock = ptp_clock_register(&ptp_vmw_clock_info, NULL);
95 if (IS_ERR(ptp_vmw_clock)) {
96 pr_err("failed to register ptp clock\n");
97 return PTR_ERR(ptp_vmw_clock);
98 }
99
100 ptp_vmw_acpi_device = device;
101 return 0;
102 }
103
ptp_vmw_acpi_remove(struct acpi_device * device)104 static void ptp_vmw_acpi_remove(struct acpi_device *device)
105 {
106 ptp_clock_unregister(ptp_vmw_clock);
107 }
108
109 static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = {
110 { "VMW0005", 0 },
111 { "", 0 },
112 };
113
114 MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids);
115
116 static struct acpi_driver ptp_vmw_acpi_driver = {
117 .name = "ptp_vmw",
118 .ids = ptp_vmw_acpi_device_ids,
119 .ops = {
120 .add = ptp_vmw_acpi_add,
121 .remove = ptp_vmw_acpi_remove
122 },
123 .owner = THIS_MODULE
124 };
125
ptp_vmw_init(void)126 static int __init ptp_vmw_init(void)
127 {
128 if (x86_hyper_type != X86_HYPER_VMWARE)
129 return -1;
130 return acpi_bus_register_driver(&ptp_vmw_acpi_driver);
131 }
132
ptp_vmw_exit(void)133 static void __exit ptp_vmw_exit(void)
134 {
135 acpi_bus_unregister_driver(&ptp_vmw_acpi_driver);
136 }
137
138 module_init(ptp_vmw_init);
139 module_exit(ptp_vmw_exit);
140
141 MODULE_DESCRIPTION("VMware virtual PTP clock driver");
142 MODULE_AUTHOR("VMware, Inc.");
143 MODULE_LICENSE("Dual BSD/GPL");
144