drivers/ptp/ptp_vmw.c

   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_CMD_PCLK(nr) ((nr << 16) | 97)
  18 #define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
  19
  20 static struct acpi_device *ptp_vmw_acpi_device;
  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_add(struct acpi_device *device)
  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
  94         ptp_vmw_acpi_device = device;
  95         return 0;
  96 }
  97
  98 static void ptp_vmw_acpi_remove(struct acpi_device *device)
  99 {
 100         ptp_clock_unregister(ptp_vmw_clock);
 101 }
 102
 103 static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = {
 104         { "VMW0005", 0 },
 105         { "", 0 },
 106 };
 107
 108 MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids);
 109
 110 static struct acpi_driver ptp_vmw_acpi_driver = {
 111         .name = "ptp_vmw",
 112         .ids = ptp_vmw_acpi_device_ids,
 113         .ops = {
 114                 .add = ptp_vmw_acpi_add,
 115                 .remove = ptp_vmw_acpi_remove
 116         },
 117 };
 118
 119 static int __init ptp_vmw_init(void)
 120 {
 121         if (x86_hyper_type != X86_HYPER_VMWARE)
 122                 return -1;
 123         return acpi_bus_register_driver(&ptp_vmw_acpi_driver);
 124 }
 125
 126 static void __exit ptp_vmw_exit(void)
 127 {
 128         acpi_bus_unregister_driver(&ptp_vmw_acpi_driver);
 129 }
 130
 131 module_init(ptp_vmw_init);
 132 module_exit(ptp_vmw_exit);
 133
 134 MODULE_DESCRIPTION("VMware virtual PTP clock driver");
 135 MODULE_AUTHOR("VMware, Inc.");
 136 MODULE_LICENSE("Dual BSD/GPL");