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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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efd8d98dfb
This patch add the HW timestamping infrastructure. The mcp251xfd has a free running timer of 32 bit width, running at max 40MHz, which wraps around every 107 seconds. The current timestamp is latched into RX and TEF objects automatically be the CAN controller. This patch sets up a cyclecounter, timecounter and delayed worker infrastructure (which runs every 45 seconds) to convert the timer into a proper 64 bit based ns timestamp. Link: https://lore.kernel.org/r/20210304160328.2752293-6-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
72 lines
1.8 KiB
C
72 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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//
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// mcp251xfd - Microchip MCP251xFD Family CAN controller driver
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//
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// Copyright (c) 2021 Pengutronix,
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// Marc Kleine-Budde <kernel@pengutronix.de>
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//
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#include <linux/clocksource.h>
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#include <linux/workqueue.h>
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#include "mcp251xfd.h"
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static u64 mcp251xfd_timestamp_read(const struct cyclecounter *cc)
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{
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struct mcp251xfd_priv *priv;
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u32 timestamp = 0;
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int err;
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priv = container_of(cc, struct mcp251xfd_priv, cc);
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err = mcp251xfd_get_timestamp(priv, ×tamp);
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if (err)
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netdev_err(priv->ndev,
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"Error %d while reading timestamp. HW timestamps may be inaccurate.",
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err);
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return timestamp;
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}
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static void mcp251xfd_timestamp_work(struct work_struct *work)
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{
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struct delayed_work *delayed_work = to_delayed_work(work);
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struct mcp251xfd_priv *priv;
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priv = container_of(delayed_work, struct mcp251xfd_priv, timestamp);
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timecounter_read(&priv->tc);
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schedule_delayed_work(&priv->timestamp,
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MCP251XFD_TIMESTAMP_WORK_DELAY_SEC * HZ);
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}
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void mcp251xfd_skb_set_timestamp(struct mcp251xfd_priv *priv,
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struct sk_buff *skb, u32 timestamp)
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{
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struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
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u64 ns;
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ns = timecounter_cyc2time(&priv->tc, timestamp);
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hwtstamps->hwtstamp = ns_to_ktime(ns);
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}
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void mcp251xfd_timestamp_init(struct mcp251xfd_priv *priv)
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{
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struct cyclecounter *cc = &priv->cc;
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cc->read = mcp251xfd_timestamp_read;
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cc->mask = CYCLECOUNTER_MASK(32);
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cc->shift = 1;
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cc->mult = clocksource_hz2mult(priv->can.clock.freq, cc->shift);
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timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
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INIT_DELAYED_WORK(&priv->timestamp, mcp251xfd_timestamp_work);
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schedule_delayed_work(&priv->timestamp,
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MCP251XFD_TIMESTAMP_WORK_DELAY_SEC * HZ);
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}
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void mcp251xfd_timestamp_stop(struct mcp251xfd_priv *priv)
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{
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cancel_delayed_work_sync(&priv->timestamp);
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}
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