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 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 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 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 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 */ 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