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/platform_device.h> 14 #include <linux/ptp_clock_kernel.h> 15 #include <asm/hypervisor.h> 16 #include <asm/vmware.h> 17 18 #define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97) 19 #define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0) 20 21 static struct ptp_clock *ptp_vmw_clock; 22 23 24 static int ptp_vmw_pclk_read(u64 *ns) 25 { 26 u32 ret, nsec_hi, nsec_lo; 27 28 ret = vmware_hypercall3(VMWARE_CMD_PCLK_GETTIME, 0, 29 &nsec_hi, &nsec_lo); 30 if (ret == 0) 31 *ns = ((u64)nsec_hi << 32) | nsec_lo; 32 return ret; 33 } 34 35 /* 36 * PTP clock ops. 37 */ 38 39 static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta) 40 { 41 return -EOPNOTSUPP; 42 } 43 44 static int ptp_vmw_adjfine(struct ptp_clock_info *info, long delta) 45 { 46 return -EOPNOTSUPP; 47 } 48 49 static int ptp_vmw_gettime(struct ptp_clock_info *info, struct timespec64 *ts) 50 { 51 u64 ns; 52 53 if (ptp_vmw_pclk_read(&ns) != 0) 54 return -EIO; 55 *ts = ns_to_timespec64(ns); 56 return 0; 57 } 58 59 static int ptp_vmw_settime(struct ptp_clock_info *info, 60 const struct timespec64 *ts) 61 { 62 return -EOPNOTSUPP; 63 } 64 65 static int ptp_vmw_enable(struct ptp_clock_info *info, 66 struct ptp_clock_request *request, int on) 67 { 68 return -EOPNOTSUPP; 69 } 70 71 static struct ptp_clock_info ptp_vmw_clock_info = { 72 .owner = THIS_MODULE, 73 .name = "ptp_vmw", 74 .max_adj = 0, 75 .adjtime = ptp_vmw_adjtime, 76 .adjfine = ptp_vmw_adjfine, 77 .gettime64 = ptp_vmw_gettime, 78 .settime64 = ptp_vmw_settime, 79 .enable = ptp_vmw_enable, 80 }; 81 82 /* 83 * ACPI driver ops for VMware "precision clock" virtual device. 84 */ 85 86 static int ptp_vmw_acpi_probe(struct platform_device *pdev) 87 { 88 ptp_vmw_clock = ptp_clock_register(&ptp_vmw_clock_info, NULL); 89 if (IS_ERR(ptp_vmw_clock)) { 90 pr_err("failed to register ptp clock\n"); 91 return PTR_ERR(ptp_vmw_clock); 92 } 93 return 0; 94 } 95 96 static void ptp_vmw_acpi_remove(struct platform_device *pdev) 97 { 98 ptp_clock_unregister(ptp_vmw_clock); 99 } 100 101 static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = { 102 { "VMW0005", 0 }, 103 { "", 0 }, 104 }; 105 106 MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids); 107 108 static struct platform_driver ptp_vmw_acpi_driver = { 109 .probe = ptp_vmw_acpi_probe, 110 .remove = ptp_vmw_acpi_remove, 111 .driver = { 112 .name = "ptp_vmw_acpi", 113 .acpi_match_table = ptp_vmw_acpi_device_ids, 114 }, 115 }; 116 117 static int __init ptp_vmw_init(void) 118 { 119 if (x86_hyper_type != X86_HYPER_VMWARE) 120 return -1; 121 return platform_driver_register(&ptp_vmw_acpi_driver); 122 } 123 124 static void __exit ptp_vmw_exit(void) 125 { 126 platform_driver_unregister(&ptp_vmw_acpi_driver); 127 } 128 129 module_init(ptp_vmw_init); 130 module_exit(ptp_vmw_exit); 131 132 MODULE_DESCRIPTION("VMware virtual PTP clock driver"); 133 MODULE_AUTHOR("VMware, Inc."); 134 MODULE_LICENSE("Dual BSD/GPL"); 135