osfmk/arm64/machine_remote_time.c

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <kern/misc_protos.h>
  29 #include <stdatomic.h>
  30 #include <mach/mach_time.h>
  31 #include <mach/clock_types.h>
  32 #include <kern/clock.h>
  33 #include <kern/locks.h>
  34 #include <arm64/machine_remote_time.h>
  35 #include <sys/kdebug.h>
  36 #include <arm/machine_routines.h>
  37
  38 lck_spin_t *bt_spin_lock = NULL;
  39 _Atomic uint32_t bt_init_flag = 0;
  40
  41 extern lck_spin_t *ts_conversion_lock;
  42 extern void mach_bridge_add_timestamp(uint64_t remote_timestamp, uint64_t local_timestamp);
  43 extern void bt_calibration_thread_start(void);
  44
  45 void
  46 mach_bridge_init_timestamp(void)
  47 {
  48         /* This function should be called only once by the driver
  49          *  implementing the interrupt handler for receiving timestamps */
  50         if (bt_init_flag) {
  51                 assert(!bt_init_flag);
  52                 return;
  53         }
  54
  55         /* Initialize the locks */
  56         static lck_grp_t *bt_lck_grp = NULL;
  57
  58         bt_lck_grp = lck_grp_alloc_init("bridgetimestamp", LCK_GRP_ATTR_NULL);
  59         bt_spin_lock = lck_spin_alloc_init(bt_lck_grp, NULL);
  60         ts_conversion_lock = lck_spin_alloc_init(bt_lck_grp, NULL);
  61
  62         atomic_store(&bt_init_flag, 1);
  63
  64         /* Start the kernel thread only after all the locks have been initialized */
  65         bt_calibration_thread_start();
  66 }
  67
  68 /*
  69  * Conditions: Should be called from primary interrupt context
  70  */
  71 void
  72 mach_bridge_recv_timestamps(uint64_t remoteTimestamp, uint64_t localTimestamp)
  73 {
  74         assert(ml_at_interrupt_context() == TRUE);
  75
  76         /* Ensure the locks have been initialized */
  77         if (!bt_init_flag) {
  78                 assert(bt_init_flag != 0);
  79                 return;
  80         }
  81
  82         KDBG(MACHDBG_CODE(DBG_MACH_CLOCK, MACH_BRIDGE_RCV_TS), localTimestamp, remoteTimestamp);
  83
  84         lck_spin_lock(bt_spin_lock);
  85         mach_bridge_add_timestamp(remoteTimestamp, localTimestamp);
  86         lck_spin_unlock(bt_spin_lock);
  87
  88         return;
  89 }