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 21static struct acpi_device *ptp_vmw_acpi_device; 22static struct ptp_clock *ptp_vmw_clock; 23 24 25static 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 45static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta) 46{ 47 return -EOPNOTSUPP; 48} 49 50static int ptp_vmw_adjfine(struct ptp_clock_info *info, long delta) 51{ 52 return -EOPNOTSUPP; 53} 54 55static 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 65static int ptp_vmw_settime(struct ptp_clock_info *info, 66 const struct timespec64 *ts) 67{ 68 return -EOPNOTSUPP; 69} 70 71static int ptp_vmw_enable(struct ptp_clock_info *info, 72 struct ptp_clock_request *request, int on) 73{ 74 return -EOPNOTSUPP; 75} 76 77static 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 92static 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 104static void ptp_vmw_acpi_remove(struct acpi_device *device) 105{ 106 ptp_clock_unregister(ptp_vmw_clock); 107} 108 109static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = { 110 { "VMW0005", 0 }, 111 { "", 0 }, 112}; 113 114MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids); 115 116static 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 126static 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 133static void __exit ptp_vmw_exit(void) 134{ 135 acpi_bus_unregister_driver(&ptp_vmw_acpi_driver); 136} 137 138module_init(ptp_vmw_init); 139module_exit(ptp_vmw_exit); 140 141MODULE_DESCRIPTION("VMware virtual PTP clock driver"); 142MODULE_AUTHOR("VMware, Inc."); 143MODULE_LICENSE("Dual BSD/GPL"); 144