xref: /dpdk/lib/eal/linux/eal_timer.c (revision daa02b5cddbb8e11b31d41e2bf7bb1ae64dcae2f)
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 <string.h>
7 #include <stdlib.h>
8 #include <stdio.h>
9 #include <stdint.h>
10 #include <unistd.h>
11 #include <fcntl.h>
12 #include <inttypes.h>
13 #include <sys/mman.h>
14 #include <sys/queue.h>
15 #include <pthread.h>
16 #include <errno.h>
17 
18 #include <rte_common.h>
19 #include <rte_log.h>
20 #include <rte_cycles.h>
21 #include <rte_lcore.h>
22 #include <rte_memory.h>
23 #include <rte_eal.h>
24 #include <rte_debug.h>
25 
26 #include "eal_private.h"
27 #include "eal_internal_cfg.h"
28 
29 enum timer_source eal_timer_source = EAL_TIMER_HPET;
30 
31 #ifdef RTE_LIBEAL_USE_HPET
32 
33 #define DEV_HPET "/dev/hpet"
34 
35 /* Maximum number of counters. */
36 #define HPET_TIMER_NUM 3
37 
38 /* General capabilities register */
39 #define CLK_PERIOD_SHIFT     32 /* Clock period shift. */
40 #define CLK_PERIOD_MASK      0xffffffff00000000ULL /* Clock period mask. */
41 
42 /**
43  * HPET timer registers. From the Intel IA-PC HPET (High Precision Event
44  * Timers) Specification.
45  */
46 struct eal_hpet_regs {
47 	/* Memory-mapped, software visible registers */
48 	uint64_t capabilities;      /**< RO General Capabilities Register. */
49 	uint64_t reserved0;         /**< Reserved for future use. */
50 	uint64_t config;            /**< RW General Configuration Register. */
51 	uint64_t reserved1;         /**< Reserved for future use. */
52 	uint64_t isr;               /**< RW Clear General Interrupt Status. */
53 	uint64_t reserved2[25];     /**< Reserved for future use. */
54 	union {
55 		uint64_t counter;   /**< RW Main Counter Value Register. */
56 		struct {
57 			uint32_t counter_l; /**< RW Main Counter Low. */
58 			uint32_t counter_h; /**< RW Main Counter High. */
59 		};
60 	};
61 	uint64_t reserved3;         /**< Reserved for future use. */
62 	struct {
63 		uint64_t config;    /**< RW Timer Config and Capability Reg. */
64 		uint64_t comp;      /**< RW Timer Comparator Value Register. */
65 		uint64_t fsb;       /**< RW FSB Interrupt Route Register. */
66 		uint64_t reserved4; /**< Reserved for future use. */
67 	} timers[HPET_TIMER_NUM]; /**< Set of HPET timers. */
68 };
69 
70 /* Mmap'd hpet registers */
71 static volatile struct eal_hpet_regs *eal_hpet = NULL;
72 
73 /* Period at which the HPET counter increments in
74  * femtoseconds (10^-15 seconds). */
75 static uint32_t eal_hpet_resolution_fs = 0;
76 
77 /* Frequency of the HPET counter in Hz */
78 static uint64_t eal_hpet_resolution_hz = 0;
79 
80 /* Incremented 4 times during one 32bits hpet full count */
81 static uint32_t eal_hpet_msb;
82 
83 static pthread_t msb_inc_thread_id;
84 
85 /*
86  * This function runs on a specific thread to update a global variable
87  * containing used to process MSB of the HPET (unfortunately, we need
88  * this because hpet is 32 bits by default under linux).
89  */
90 static void *
91 hpet_msb_inc(__rte_unused void *arg)
92 {
93 	uint32_t t;
94 
95 	while (1) {
96 		t = (eal_hpet->counter_l >> 30);
97 		if (t != (eal_hpet_msb & 3))
98 			eal_hpet_msb ++;
99 		sleep(10);
100 	}
101 	return NULL;
102 }
103 
104 uint64_t
105 rte_get_hpet_hz(void)
106 {
107 	const struct internal_config *internal_conf =
108 		eal_get_internal_configuration();
109 
110 	if (internal_conf->no_hpet)
111 		rte_panic("Error, HPET called, but no HPET present\n");
112 
113 	return eal_hpet_resolution_hz;
114 }
115 
116 uint64_t
117 rte_get_hpet_cycles(void)
118 {
119 	uint32_t t, msb;
120 	uint64_t ret;
121 	const struct internal_config *internal_conf =
122 		eal_get_internal_configuration();
123 
124 	if (internal_conf->no_hpet)
125 		rte_panic("Error, HPET called, but no HPET present\n");
126 
127 	t = eal_hpet->counter_l;
128 	msb = eal_hpet_msb;
129 	ret = (msb + 2 - (t >> 30)) / 4;
130 	ret <<= 32;
131 	ret += t;
132 	return ret;
133 }
134 
135 #endif
136 
137 #ifdef RTE_LIBEAL_USE_HPET
138 /*
139  * Open and mmap /dev/hpet (high precision event timer) that will
140  * provide our time reference.
141  */
142 int
143 rte_eal_hpet_init(int make_default)
144 {
145 	int fd, ret;
146 	struct internal_config *internal_conf =
147 		eal_get_internal_configuration();
148 
149 	if (internal_conf->no_hpet) {
150 		RTE_LOG(NOTICE, EAL, "HPET is disabled\n");
151 		return -1;
152 	}
153 
154 	fd = open(DEV_HPET, O_RDONLY);
155 	if (fd < 0) {
156 		RTE_LOG(ERR, EAL, "ERROR: Cannot open "DEV_HPET": %s!\n",
157 			strerror(errno));
158 		internal_conf->no_hpet = 1;
159 		return -1;
160 	}
161 	eal_hpet = mmap(NULL, 1024, PROT_READ, MAP_SHARED, fd, 0);
162 	if (eal_hpet == MAP_FAILED) {
163 		RTE_LOG(ERR, EAL, "ERROR: Cannot mmap "DEV_HPET"!\n"
164 				"Please enable CONFIG_HPET_MMAP in your kernel configuration "
165 				"to allow HPET support.\n"
166 				"To run without using HPET, unset RTE_LIBEAL_USE_HPET "
167 				"in your build configuration or use '--no-hpet' EAL flag.\n");
168 		close(fd);
169 		internal_conf->no_hpet = 1;
170 		return -1;
171 	}
172 	close(fd);
173 
174 	eal_hpet_resolution_fs = (uint32_t)((eal_hpet->capabilities &
175 					CLK_PERIOD_MASK) >>
176 					CLK_PERIOD_SHIFT);
177 
178 	eal_hpet_resolution_hz = (1000ULL*1000ULL*1000ULL*1000ULL*1000ULL) /
179 		(uint64_t)eal_hpet_resolution_fs;
180 
181 	RTE_LOG(INFO, EAL, "HPET frequency is ~%"PRIu64" kHz\n",
182 			eal_hpet_resolution_hz/1000);
183 
184 	eal_hpet_msb = (eal_hpet->counter_l >> 30);
185 
186 	/* create a thread that will increment a global variable for
187 	 * msb (hpet is 32 bits by default under linux) */
188 	ret = rte_ctrl_thread_create(&msb_inc_thread_id, "hpet-msb-inc", NULL,
189 				     hpet_msb_inc, NULL);
190 	if (ret != 0) {
191 		RTE_LOG(ERR, EAL, "ERROR: Cannot create HPET timer thread!\n");
192 		internal_conf->no_hpet = 1;
193 		return -1;
194 	}
195 
196 	if (make_default)
197 		eal_timer_source = EAL_TIMER_HPET;
198 	return 0;
199 }
200 #endif
201 
202 uint64_t
203 get_tsc_freq(void)
204 {
205 #ifdef CLOCK_MONOTONIC_RAW
206 #define NS_PER_SEC 1E9
207 #define CYC_PER_10MHZ 1E7
208 
209 	struct timespec sleeptime = {.tv_nsec = NS_PER_SEC / 10 }; /* 1/10 second */
210 
211 	struct timespec t_start, t_end;
212 	uint64_t tsc_hz;
213 
214 	if (clock_gettime(CLOCK_MONOTONIC_RAW, &t_start) == 0) {
215 		uint64_t ns, end, start = rte_rdtsc();
216 		nanosleep(&sleeptime,NULL);
217 		clock_gettime(CLOCK_MONOTONIC_RAW, &t_end);
218 		end = rte_rdtsc();
219 		ns = ((t_end.tv_sec - t_start.tv_sec) * NS_PER_SEC);
220 		ns += (t_end.tv_nsec - t_start.tv_nsec);
221 
222 		double secs = (double)ns/NS_PER_SEC;
223 		tsc_hz = (uint64_t)((end - start)/secs);
224 		/* Round up to 10Mhz. 1E7 ~ 10Mhz */
225 		return RTE_ALIGN_MUL_NEAR(tsc_hz, CYC_PER_10MHZ);
226 	}
227 #endif
228 	return 0;
229 }
230 
231 int
232 rte_eal_timer_init(void)
233 {
234 
235 	eal_timer_source = EAL_TIMER_TSC;
236 
237 	set_tsc_freq();
238 	return 0;
239 }
240