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7d10001e VT |
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 | ||
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 | ||
45 | static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta) | |
46 | { | |
47 | return -EOPNOTSUPP; | |
48 | } | |
49 | ||
50 | static int ptp_vmw_adjfreq(struct ptp_clock_info *info, s32 delta) | |
51 | { | |
52 | return -EOPNOTSUPP; | |
53 | } | |
54 | ||
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 | ||
65 | static int ptp_vmw_settime(struct ptp_clock_info *info, | |
66 | const struct timespec64 *ts) | |
67 | { | |
68 | return -EOPNOTSUPP; | |
69 | } | |
70 | ||
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 | .adjfreq = ptp_vmw_adjfreq, | |
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 | ||
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 | ||
104 | static int ptp_vmw_acpi_remove(struct acpi_device *device) | |
105 | { | |
106 | ptp_clock_unregister(ptp_vmw_clock); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = { | |
111 | { "VMW0005", 0 }, | |
112 | { "", 0 }, | |
113 | }; | |
114 | ||
115 | MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids); | |
116 | ||
117 | static struct acpi_driver ptp_vmw_acpi_driver = { | |
118 | .name = "ptp_vmw", | |
119 | .ids = ptp_vmw_acpi_device_ids, | |
120 | .ops = { | |
121 | .add = ptp_vmw_acpi_add, | |
122 | .remove = ptp_vmw_acpi_remove | |
123 | }, | |
124 | .owner = THIS_MODULE | |
125 | }; | |
126 | ||
127 | static int __init ptp_vmw_init(void) | |
128 | { | |
129 | if (x86_hyper_type != X86_HYPER_VMWARE) | |
130 | return -1; | |
131 | return acpi_bus_register_driver(&ptp_vmw_acpi_driver); | |
132 | } | |
133 | ||
134 | static void __exit ptp_vmw_exit(void) | |
135 | { | |
136 | acpi_bus_unregister_driver(&ptp_vmw_acpi_driver); | |
137 | } | |
138 | ||
139 | module_init(ptp_vmw_init); | |
140 | module_exit(ptp_vmw_exit); | |
141 | ||
142 | MODULE_DESCRIPTION("VMware virtual PTP clock driver"); | |
143 | MODULE_AUTHOR("VMware, Inc."); | |
144 | MODULE_LICENSE("Dual BSD/GPL"); |