lib/eal/linux/eal_timer.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation.
   3  * Copyright(c) 2012-2013 6WIND S.A.
   4  */
   5
   6 #include <stdio.h>
   7 #include <stdint.h>
   8
   9 #include <rte_common.h>
  10 #include <rte_cycles.h>
  11
  12 #include "eal_private.h"
  13
  14 enum timer_source eal_timer_source = EAL_TIMER_HPET;
  15
  16 #ifdef RTE_LIBEAL_USE_HPET
  17
  18 #define DEV_HPET "/dev/hpet"
  19
  20 /* Maximum number of counters. */
  21 #define HPET_TIMER_NUM 3
  22
  23 /* General capabilities register */
  24 #define CLK_PERIOD_SHIFT     32 /* Clock period shift. */
  25 #define CLK_PERIOD_MASK      0xffffffff00000000ULL /* Clock period mask. */
  26
  27 /**
  28  * HPET timer registers. From the Intel IA-PC HPET (High Precision Event
  29  * Timers) Specification.
  30  */
  31 struct eal_hpet_regs {
  32         /* Memory-mapped, software visible registers */
  33         uint64_t capabilities;      /**< RO General Capabilities Register. */
  34         uint64_t reserved0;         /**< Reserved for future use. */
  35         uint64_t config;            /**< RW General Configuration Register. */
  36         uint64_t reserved1;         /**< Reserved for future use. */
  37         uint64_t isr;               /**< RW Clear General Interrupt Status. */
  38         uint64_t reserved2[25];     /**< Reserved for future use. */
  39         union {
  40                 uint64_t counter;   /**< RW Main Counter Value Register. */
  41                 struct {
  42                         uint32_t counter_l; /**< RW Main Counter Low. */
  43                         uint32_t counter_h; /**< RW Main Counter High. */
  44                 };
  45         };
  46         uint64_t reserved3;         /**< Reserved for future use. */
  47         struct {
  48                 uint64_t config;    /**< RW Timer Config and Capability Reg. */
  49                 uint64_t comp;      /**< RW Timer Comparator Value Register. */
  50                 uint64_t fsb;       /**< RW FSB Interrupt Route Register. */
  51                 uint64_t reserved4; /**< Reserved for future use. */
  52         } timers[HPET_TIMER_NUM]; /**< Set of HPET timers. */
  53 };
  54
  55 /* Mmap'd hpet registers */
  56 static volatile struct eal_hpet_regs *eal_hpet = NULL;
  57
  58 /* Period at which the HPET counter increments in
  59  * femtoseconds (10^-15 seconds). */
  60 static uint32_t eal_hpet_resolution_fs = 0;
  61
  62 /* Frequency of the HPET counter in Hz */
  63 static uint64_t eal_hpet_resolution_hz = 0;
  64
  65 /* Incremented 4 times during one 32bits hpet full count */
  66 static uint32_t eal_hpet_msb;
  67
  68 static pthread_t msb_inc_thread_id;
  69
  70 /*
  71  * This function runs on a specific thread to update a global variable
  72  * containing used to process MSB of the HPET (unfortunately, we need
  73  * this because hpet is 32 bits by default under linux).
  74  */
  75 static void *
  76 hpet_msb_inc(__rte_unused void *arg)
  77 {
  78         uint32_t t;
  79
  80         while (1) {
  81                 t = (eal_hpet->counter_l >> 30);
  82                 if (t != (eal_hpet_msb & 3))
  83                         eal_hpet_msb ++;
  84                 sleep(10);
  85         }
  86         return NULL;
  87 }
  88
  89 uint64_t
  90 rte_get_hpet_hz(void)
  91 {
  92         const struct internal_config *internal_conf =
  93                 eal_get_internal_configuration();
  94
  95         if (internal_conf->no_hpet)
  96                 rte_panic("Error, HPET called, but no HPET present\n");
  97
  98         return eal_hpet_resolution_hz;
  99 }
 100
 101 uint64_t
 102 rte_get_hpet_cycles(void)
 103 {
 104         uint32_t t, msb;
 105         uint64_t ret;
 106         const struct internal_config *internal_conf =
 107                 eal_get_internal_configuration();
 108
 109         if (internal_conf->no_hpet)
 110                 rte_panic("Error, HPET called, but no HPET present\n");
 111
 112         t = eal_hpet->counter_l;
 113         msb = eal_hpet_msb;
 114         ret = (msb + 2 - (t >> 30)) / 4;
 115         ret <<= 32;
 116         ret += t;
 117         return ret;
 118 }
 119
 120 #endif
 121
 122 #ifdef RTE_LIBEAL_USE_HPET
 123 /*
 124  * Open and mmap /dev/hpet (high precision event timer) that will
 125  * provide our time reference.
 126  */
 127 int
 128 rte_eal_hpet_init(int make_default)
 129 {
 130         int fd, ret;
 131         struct internal_config *internal_conf =
 132                 eal_get_internal_configuration();
 133
 134         if (internal_conf->no_hpet) {
 135                 RTE_LOG(NOTICE, EAL, "HPET is disabled\n");
 136                 return -1;
 137         }
 138
 139         fd = open(DEV_HPET, O_RDONLY);
 140         if (fd < 0) {
 141                 RTE_LOG(ERR, EAL, "ERROR: Cannot open "DEV_HPET": %s!\n",
 142                         strerror(errno));
 143                 internal_conf->no_hpet = 1;
 144                 return -1;
 145         }
 146         eal_hpet = mmap(NULL, 1024, PROT_READ, MAP_SHARED, fd, 0);
 147         if (eal_hpet == MAP_FAILED) {
 148                 RTE_LOG(ERR, EAL, "ERROR: Cannot mmap "DEV_HPET"!\n"
 149                                 "Please enable CONFIG_HPET_MMAP in your kernel configuration "
 150                                 "to allow HPET support.\n"
 151                                 "To run without using HPET, unset RTE_LIBEAL_USE_HPET "
 152                                 "in your build configuration or use '--no-hpet' EAL flag.\n");
 153                 close(fd);
 154                 internal_conf->no_hpet = 1;
 155                 return -1;
 156         }
 157         close(fd);
 158
 159         eal_hpet_resolution_fs = (uint32_t)((eal_hpet->capabilities &
 160                                         CLK_PERIOD_MASK) >>
 161                                         CLK_PERIOD_SHIFT);
 162
 163         eal_hpet_resolution_hz = (1000ULL*1000ULL*1000ULL*1000ULL*1000ULL) /
 164                 (uint64_t)eal_hpet_resolution_fs;
 165
 166         RTE_LOG(INFO, EAL, "HPET frequency is ~%"PRIu64" kHz\n",
 167                         eal_hpet_resolution_hz/1000);
 168
 169         eal_hpet_msb = (eal_hpet->counter_l >> 30);
 170
 171         /* create a thread that will increment a global variable for
 172          * msb (hpet is 32 bits by default under linux) */
 173         ret = rte_ctrl_thread_create(&msb_inc_thread_id, "hpet-msb-inc", NULL,
 174                                      hpet_msb_inc, NULL);
 175         if (ret != 0) {
 176                 RTE_LOG(ERR, EAL, "ERROR: Cannot create HPET timer thread!\n");
 177                 internal_conf->no_hpet = 1;
 178                 return -1;
 179         }
 180
 181         if (make_default)
 182                 eal_timer_source = EAL_TIMER_HPET;
 183         return 0;
 184 }
 185 #endif
 186
 187 uint64_t
 188 get_tsc_freq(void)
 189 {
 190 #ifdef CLOCK_MONOTONIC_RAW
 191 #define NS_PER_SEC 1E9
 192 #define CYC_PER_10MHZ 1E7
 193
 194         struct timespec sleeptime = {.tv_nsec = NS_PER_SEC / 10 }; /* 1/10 second */
 195
 196         struct timespec t_start, t_end;
 197         uint64_t tsc_hz;
 198
 199         if (clock_gettime(CLOCK_MONOTONIC_RAW, &t_start) == 0) {
 200                 uint64_t ns, end, start = rte_rdtsc();
 201                 nanosleep(&sleeptime,NULL);
 202                 clock_gettime(CLOCK_MONOTONIC_RAW, &t_end);
 203                 end = rte_rdtsc();
 204                 ns = ((t_end.tv_sec - t_start.tv_sec) * NS_PER_SEC);
 205                 ns += (t_end.tv_nsec - t_start.tv_nsec);
 206
 207                 double secs = (double)ns/NS_PER_SEC;
 208                 tsc_hz = (uint64_t)((end - start)/secs);
 209                 /* Round up to 10Mhz. 1E7 ~ 10Mhz */
 210                 return RTE_ALIGN_MUL_NEAR(tsc_hz, CYC_PER_10MHZ);
 211         }
 212 #endif
 213         return 0;
 214 }
 215
 216 int
 217 rte_eal_timer_init(void)
 218 {
 219
 220         eal_timer_source = EAL_TIMER_TSC;
 221
 222         set_tsc_freq();
 223         return 0;
 224 }