1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright (c) 2023, 2024 Pengutronix,
4 // Marc Kleine-Budde <kernel@pengutronix.de>
5 //
6
7 #include <linux/clocksource.h>
8
9 #include "rockchip_canfd.h"
10
rkcanfd_timestamp_read(const struct cyclecounter * cc)11 static u64 rkcanfd_timestamp_read(const struct cyclecounter *cc)
12 {
13 const struct rkcanfd_priv *priv = container_of(cc, struct rkcanfd_priv, cc);
14
15 return rkcanfd_get_timestamp(priv);
16 }
17
rkcanfd_skb_set_timestamp(const struct rkcanfd_priv * priv,struct sk_buff * skb,const u32 timestamp)18 void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
19 struct sk_buff *skb, const u32 timestamp)
20 {
21 struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
22 u64 ns;
23
24 ns = timecounter_cyc2time(&priv->tc, timestamp);
25
26 hwtstamps->hwtstamp = ns_to_ktime(ns);
27 }
28
rkcanfd_timestamp_work(struct work_struct * work)29 static void rkcanfd_timestamp_work(struct work_struct *work)
30 {
31 const struct delayed_work *delayed_work = to_delayed_work(work);
32 struct rkcanfd_priv *priv;
33
34 priv = container_of(delayed_work, struct rkcanfd_priv, timestamp);
35 timecounter_read(&priv->tc);
36
37 schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
38 }
39
rkcanfd_timestamp_init(struct rkcanfd_priv * priv)40 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
41 {
42 const struct can_bittiming *dbt = &priv->can.data_bittiming;
43 const struct can_bittiming *bt = &priv->can.bittiming;
44 struct cyclecounter *cc = &priv->cc;
45 u32 bitrate, div, reg, rate;
46 u64 work_delay_ns;
47 u64 max_cycles;
48
49 /* At the standard clock rate of 300Mhz on the rk3658, the 32
50 * bit timer overflows every 14s. This means that we have to
51 * poll it quite often to avoid missing a wrap around.
52 *
53 * Divide it down to a reasonable rate, at least twice the bit
54 * rate.
55 */
56 bitrate = max(bt->bitrate, dbt->bitrate);
57 div = min(DIV_ROUND_UP(priv->can.clock.freq, bitrate * 2),
58 FIELD_MAX(RKCANFD_REG_TIMESTAMP_CTRL_TIME_BASE_COUNTER_PRESCALE) + 1);
59
60 reg = FIELD_PREP(RKCANFD_REG_TIMESTAMP_CTRL_TIME_BASE_COUNTER_PRESCALE,
61 div - 1) |
62 RKCANFD_REG_TIMESTAMP_CTRL_TIME_BASE_COUNTER_ENABLE;
63 rkcanfd_write(priv, RKCANFD_REG_TIMESTAMP_CTRL, reg);
64
65 cc->read = rkcanfd_timestamp_read;
66 cc->mask = CYCLECOUNTER_MASK(32);
67
68 rate = priv->can.clock.freq / div;
69 clocks_calc_mult_shift(&cc->mult, &cc->shift, rate, NSEC_PER_SEC,
70 RKCANFD_TIMESTAMP_WORK_MAX_DELAY_SEC);
71
72 max_cycles = div_u64(ULLONG_MAX, cc->mult);
73 max_cycles = min(max_cycles, cc->mask);
74 work_delay_ns = clocksource_cyc2ns(max_cycles, cc->mult, cc->shift);
75 priv->work_delay_jiffies = div_u64(work_delay_ns, 3u * NSEC_PER_SEC / HZ);
76 INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
77
78 netdev_dbg(priv->ndev, "clock=%lu.%02luMHz bitrate=%lu.%02luMBit/s div=%u rate=%lu.%02luMHz mult=%u shift=%u delay=%lus\n",
79 priv->can.clock.freq / MEGA,
80 priv->can.clock.freq % MEGA / KILO / 10,
81 bitrate / MEGA,
82 bitrate % MEGA / KILO / 100,
83 div,
84 rate / MEGA,
85 rate % MEGA / KILO / 10,
86 cc->mult, cc->shift,
87 priv->work_delay_jiffies / HZ);
88 }
89
rkcanfd_timestamp_start(struct rkcanfd_priv * priv)90 void rkcanfd_timestamp_start(struct rkcanfd_priv *priv)
91 {
92 timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
93
94 schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
95 }
96
rkcanfd_timestamp_stop(struct rkcanfd_priv * priv)97 void rkcanfd_timestamp_stop(struct rkcanfd_priv *priv)
98 {
99 cancel_delayed_work(&priv->timestamp);
100 }
101
rkcanfd_timestamp_stop_sync(struct rkcanfd_priv * priv)102 void rkcanfd_timestamp_stop_sync(struct rkcanfd_priv *priv)
103 {
104 cancel_delayed_work_sync(&priv->timestamp);
105 }
106