1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright(c) 2023 Intel Corporation */
3
4 #include <linux/delay.h>
5 #include <linux/dev_printk.h>
6 #include <linux/export.h>
7 #include <linux/math.h>
8 #include <linux/minmax.h>
9 #include <linux/time64.h>
10 #include <linux/types.h>
11 #include <linux/units.h>
12 #include <asm/errno.h>
13 #include "adf_admin.h"
14 #include "adf_accel_devices.h"
15 #include "adf_clock.h"
16 #include "adf_common_drv.h"
17
18 #define MEASURE_CLOCK_RETRIES 10
19 #define MEASURE_CLOCK_DELAY_US 10000
20 #define ME_CLK_DIVIDER 16
21 #define MEASURE_CLOCK_DELTA_THRESHOLD_US 100
22
timespec_to_us(const struct timespec64 * ts)23 static inline u64 timespec_to_us(const struct timespec64 *ts)
24 {
25 return (u64)DIV_ROUND_CLOSEST_ULL(timespec64_to_ns(ts), NSEC_PER_USEC);
26 }
27
timespec_to_ms(const struct timespec64 * ts)28 static inline u64 timespec_to_ms(const struct timespec64 *ts)
29 {
30 return (u64)DIV_ROUND_CLOSEST_ULL(timespec64_to_ns(ts), NSEC_PER_MSEC);
31 }
32
adf_clock_get_current_time(void)33 u64 adf_clock_get_current_time(void)
34 {
35 struct timespec64 ts;
36
37 ktime_get_real_ts64(&ts);
38 return timespec_to_ms(&ts);
39 }
40
measure_clock(struct adf_accel_dev * accel_dev,u32 * frequency)41 static int measure_clock(struct adf_accel_dev *accel_dev, u32 *frequency)
42 {
43 struct timespec64 ts1, ts2, ts3, ts4;
44 u64 timestamp1, timestamp2, temp;
45 u32 delta_us, tries;
46 int ret;
47
48 tries = MEASURE_CLOCK_RETRIES;
49 do {
50 ktime_get_real_ts64(&ts1);
51 ret = adf_get_fw_timestamp(accel_dev, ×tamp1);
52 if (ret) {
53 dev_err(&GET_DEV(accel_dev),
54 "Failed to get fw timestamp\n");
55 return ret;
56 }
57 ktime_get_real_ts64(&ts2);
58 delta_us = timespec_to_us(&ts2) - timespec_to_us(&ts1);
59 } while (delta_us > MEASURE_CLOCK_DELTA_THRESHOLD_US && --tries);
60
61 if (!tries) {
62 dev_err(&GET_DEV(accel_dev), "Excessive clock measure delay\n");
63 return -ETIMEDOUT;
64 }
65
66 fsleep(MEASURE_CLOCK_DELAY_US);
67
68 tries = MEASURE_CLOCK_RETRIES;
69 do {
70 ktime_get_real_ts64(&ts3);
71 if (adf_get_fw_timestamp(accel_dev, ×tamp2)) {
72 dev_err(&GET_DEV(accel_dev),
73 "Failed to get fw timestamp\n");
74 return -EIO;
75 }
76 ktime_get_real_ts64(&ts4);
77 delta_us = timespec_to_us(&ts4) - timespec_to_us(&ts3);
78 } while (delta_us > MEASURE_CLOCK_DELTA_THRESHOLD_US && --tries);
79
80 if (!tries) {
81 dev_err(&GET_DEV(accel_dev), "Excessive clock measure delay\n");
82 return -ETIMEDOUT;
83 }
84
85 delta_us = timespec_to_us(&ts3) - timespec_to_us(&ts1);
86 if (!delta_us)
87 return -EINVAL;
88
89 temp = (timestamp2 - timestamp1) * ME_CLK_DIVIDER * 10;
90 temp = DIV_ROUND_CLOSEST_ULL(temp, delta_us);
91 /*
92 * Enclose the division to allow the preprocessor to precalculate it,
93 * and avoid promoting r-value to 64-bit before division.
94 */
95 *frequency = temp * (HZ_PER_MHZ / 10);
96
97 return 0;
98 }
99
100 /**
101 * adf_dev_measure_clock() - measures device clock frequency
102 * @accel_dev: Pointer to acceleration device.
103 * @frequency: Pointer to variable where result will be stored
104 * @min: Minimal allowed frequency value
105 * @max: Maximal allowed frequency value
106 *
107 * If the measurement result will go beyond the min/max thresholds the value
108 * will take the value of the crossed threshold.
109 *
110 * This algorithm compares the device firmware timestamp with the kernel
111 * timestamp. So we can't expect too high accuracy from this measurement.
112 *
113 * Return:
114 * * 0 - measurement succeed
115 * * -ETIMEDOUT - measurement failed
116 */
adf_dev_measure_clock(struct adf_accel_dev * accel_dev,u32 * frequency,u32 min,u32 max)117 int adf_dev_measure_clock(struct adf_accel_dev *accel_dev,
118 u32 *frequency, u32 min, u32 max)
119 {
120 int ret;
121 u32 freq;
122
123 ret = measure_clock(accel_dev, &freq);
124 if (ret)
125 return ret;
126
127 *frequency = clamp(freq, min, max);
128
129 if (*frequency != freq)
130 dev_warn(&GET_DEV(accel_dev),
131 "Measured clock %d Hz is out of range, assuming %d\n",
132 freq, *frequency);
133 return 0;
134 }
135 EXPORT_SYMBOL_GPL(adf_dev_measure_clock);
136