xref: /openbmc/linux/lib/dim/dim.c (revision 7c2435ef)
1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /*
3  * Copyright (c) 2019, Mellanox Technologies inc.  All rights reserved.
4  */
5 
6 #include <linux/dim.h>
7 
8 bool dim_on_top(struct dim *dim)
9 {
10 	switch (dim->tune_state) {
11 	case DIM_PARKING_ON_TOP:
12 	case DIM_PARKING_TIRED:
13 		return true;
14 	case DIM_GOING_RIGHT:
15 		return (dim->steps_left > 1) && (dim->steps_right == 1);
16 	default: /* DIM_GOING_LEFT */
17 		return (dim->steps_right > 1) && (dim->steps_left == 1);
18 	}
19 }
20 EXPORT_SYMBOL(dim_on_top);
21 
22 void dim_turn(struct dim *dim)
23 {
24 	switch (dim->tune_state) {
25 	case DIM_PARKING_ON_TOP:
26 	case DIM_PARKING_TIRED:
27 		break;
28 	case DIM_GOING_RIGHT:
29 		dim->tune_state = DIM_GOING_LEFT;
30 		dim->steps_left = 0;
31 		break;
32 	case DIM_GOING_LEFT:
33 		dim->tune_state = DIM_GOING_RIGHT;
34 		dim->steps_right = 0;
35 		break;
36 	}
37 }
38 EXPORT_SYMBOL(dim_turn);
39 
40 void dim_park_on_top(struct dim *dim)
41 {
42 	dim->steps_right  = 0;
43 	dim->steps_left   = 0;
44 	dim->tired        = 0;
45 	dim->tune_state   = DIM_PARKING_ON_TOP;
46 }
47 EXPORT_SYMBOL(dim_park_on_top);
48 
49 void dim_park_tired(struct dim *dim)
50 {
51 	dim->steps_right  = 0;
52 	dim->steps_left   = 0;
53 	dim->tune_state   = DIM_PARKING_TIRED;
54 }
55 EXPORT_SYMBOL(dim_park_tired);
56 
57 bool dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
58 		    struct dim_stats *curr_stats)
59 {
60 	/* u32 holds up to 71 minutes, should be enough */
61 	u32 delta_us = ktime_us_delta(end->time, start->time);
62 	u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr);
63 	u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr,
64 			     start->byte_ctr);
65 	u32 ncomps = BIT_GAP(BITS_PER_TYPE(u32), end->comp_ctr,
66 			     start->comp_ctr);
67 
68 	if (!delta_us)
69 		return false;
70 
71 	curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us);
72 	curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us);
73 	curr_stats->epms = DIV_ROUND_UP(DIM_NEVENTS * USEC_PER_MSEC,
74 					delta_us);
75 	curr_stats->cpms = DIV_ROUND_UP(ncomps * USEC_PER_MSEC, delta_us);
76 	if (curr_stats->epms != 0)
77 		curr_stats->cpe_ratio = DIV_ROUND_DOWN_ULL(
78 			curr_stats->cpms * 100, curr_stats->epms);
79 	else
80 		curr_stats->cpe_ratio = 0;
81 
82 	return true;
83 }
84 EXPORT_SYMBOL(dim_calc_stats);
85