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"); 145