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_adjfine(struct ptp_clock_info *info, long 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: &ns) != 0) |
60 | return -EIO; |
61 | *ts = ns_to_timespec64(nsec: 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 | .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 | |
92 | static int ptp_vmw_acpi_add(struct acpi_device *device) |
93 | { |
94 | ptp_vmw_clock = ptp_clock_register(info: &ptp_vmw_clock_info, NULL); |
95 | if (IS_ERR(ptr: ptp_vmw_clock)) { |
96 | pr_err("failed to register ptp clock\n" ); |
97 | return PTR_ERR(ptr: ptp_vmw_clock); |
98 | } |
99 | |
100 | ptp_vmw_acpi_device = device; |
101 | return 0; |
102 | } |
103 | |
104 | static void ptp_vmw_acpi_remove(struct acpi_device *device) |
105 | { |
106 | ptp_clock_unregister(ptp: 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 | |
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(driver: &ptp_vmw_acpi_driver); |
131 | } |
132 | |
133 | static void __exit ptp_vmw_exit(void) |
134 | { |
135 | acpi_bus_unregister_driver(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 | |