/*
* Copyright (c) 2017 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <kern/misc_protos.h>
#include <x86_64/machine_remote_time.h>
#include <machine/atomic.h>
#include <kern/locks.h>
#include <kern/clock.h>
#include <kern/remote_time.h>
void mach_bridge_send_timestamp(uint64_t timestamp);
extern _Atomic uint32_t bt_init_flag;
extern uint32_t bt_enable_flag;
/*
* Delay sending timestamps by certain interval to
* avoid overwriting sentinel values
*/
#define DELAY_INTERVAL_NS (50 * NSEC_PER_MSEC)
static uint64_t bt_delay_timestamp = 0;
static mach_bridge_regwrite_timestamp_func_t bridge_regwrite_timestamp_callback = NULL;
/*
* This function should only be called by the kext
* responsible for sending timestamps across the link
*/
void
mach_bridge_register_regwrite_timestamp_callback(mach_bridge_regwrite_timestamp_func_t func)
{
static uint64_t delay_amount = 0;
if (!os_atomic_load(&bt_init_flag, relaxed)) {
nanoseconds_to_absolutetime(DELAY_INTERVAL_NS, &delay_amount);
os_atomic_store(&bt_init_flag, 1, release);
}
lck_spin_lock(&bt_maintenance_lock);
bridge_regwrite_timestamp_callback = func;
bt_enable_flag = (func != NULL) ? 1 : 0;
bt_delay_timestamp = mach_absolute_time() + delay_amount;
lck_spin_unlock(&bt_maintenance_lock);
}
void
mach_bridge_send_timestamp(uint64_t timestamp)
{
LCK_SPIN_ASSERT(&bt_maintenance_lock, LCK_ASSERT_OWNED);
if (bt_delay_timestamp > 0) {
uint64_t now = mach_absolute_time();
if (now < bt_delay_timestamp) {
return;
}
bt_delay_timestamp = 0;
}
if (bridge_regwrite_timestamp_callback) {
bridge_regwrite_timestamp_callback(timestamp);
}
}