blob: 5dca26e14bdc84704fe513c874f776c8c3ecf32c [file] [log] [blame] [edit]
// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
/*
* Copyright (C) 2020 VMware, Inc., Palo Alto, CA., USA
*
* PTP clock driver for VMware precision clock virtual device.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/acpi.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ptp_clock_kernel.h>
#include <asm/hypervisor.h>
#include <asm/vmware.h>
#define VMWARE_MAGIC 0x564D5868
#define VMWARE_CMD_PCLK(nr) ((nr << 16) | 97)
#define VMWARE_CMD_PCLK_GETTIME VMWARE_CMD_PCLK(0)
static struct acpi_device *ptp_vmw_acpi_device;
static struct ptp_clock *ptp_vmw_clock;
static int ptp_vmw_pclk_read(u64 *ns)
{
u32 ret, nsec_hi, nsec_lo, unused1, unused2, unused3;
asm volatile (VMWARE_HYPERCALL :
"=a"(ret), "=b"(nsec_hi), "=c"(nsec_lo), "=d"(unused1),
"=S"(unused2), "=D"(unused3) :
"a"(VMWARE_MAGIC), "b"(0),
"c"(VMWARE_CMD_PCLK_GETTIME), "d"(0) :
"memory");
if (ret == 0)
*ns = ((u64)nsec_hi << 32) | nsec_lo;
return ret;
}
/*
* PTP clock ops.
*/
static int ptp_vmw_adjtime(struct ptp_clock_info *info, s64 delta)
{
return -EOPNOTSUPP;
}
static int ptp_vmw_adjfreq(struct ptp_clock_info *info, s32 delta)
{
return -EOPNOTSUPP;
}
static int ptp_vmw_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
{
u64 ns;
if (ptp_vmw_pclk_read(&ns) != 0)
return -EIO;
*ts = ns_to_timespec64(ns);
return 0;
}
static int ptp_vmw_settime(struct ptp_clock_info *info,
const struct timespec64 *ts)
{
return -EOPNOTSUPP;
}
static int ptp_vmw_enable(struct ptp_clock_info *info,
struct ptp_clock_request *request, int on)
{
return -EOPNOTSUPP;
}
static struct ptp_clock_info ptp_vmw_clock_info = {
.owner = THIS_MODULE,
.name = "ptp_vmw",
.max_adj = 0,
.adjtime = ptp_vmw_adjtime,
.adjfreq = ptp_vmw_adjfreq,
.gettime64 = ptp_vmw_gettime,
.settime64 = ptp_vmw_settime,
.enable = ptp_vmw_enable,
};
/*
* ACPI driver ops for VMware "precision clock" virtual device.
*/
static int ptp_vmw_acpi_add(struct acpi_device *device)
{
ptp_vmw_clock = ptp_clock_register(&ptp_vmw_clock_info, NULL);
if (IS_ERR(ptp_vmw_clock)) {
pr_err("failed to register ptp clock\n");
return PTR_ERR(ptp_vmw_clock);
}
ptp_vmw_acpi_device = device;
return 0;
}
static int ptp_vmw_acpi_remove(struct acpi_device *device)
{
ptp_clock_unregister(ptp_vmw_clock);
return 0;
}
static const struct acpi_device_id ptp_vmw_acpi_device_ids[] = {
{ "VMW0005", 0 },
{ "", 0 },
};
MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids);
static struct acpi_driver ptp_vmw_acpi_driver = {
.name = "ptp_vmw",
.ids = ptp_vmw_acpi_device_ids,
.ops = {
.add = ptp_vmw_acpi_add,
.remove = ptp_vmw_acpi_remove
},
.owner = THIS_MODULE
};
static int __init ptp_vmw_init(void)
{
if (x86_hyper_type != X86_HYPER_VMWARE)
return -1;
return acpi_bus_register_driver(&ptp_vmw_acpi_driver);
}
static void __exit ptp_vmw_exit(void)
{
acpi_bus_unregister_driver(&ptp_vmw_acpi_driver);
}
module_init(ptp_vmw_init);
module_exit(ptp_vmw_exit);
MODULE_DESCRIPTION("VMware virtual PTP clock driver");
MODULE_AUTHOR("VMware, Inc.");
MODULE_LICENSE("Dual BSD/GPL");