path: root/drivers/net/dsa/sja1105/sja1105_ptp.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
 */
#include <linux/spi/spi.h>
#include "sja1105.h"

/* The adjfine API clamps ppb between [-32,768,000, 32,768,000], and
 * therefore scaled_ppm between [-2,147,483,648, 2,147,483,647].
 * Set the maximum supported ppb to a round value smaller than the maximum.
 *
 * Percentually speaking, this is a +/- 0.032x adjustment of the
 * free-running counter (0.968x to 1.032x).
 */
#define SJA1105_MAX_ADJ_PPB		32000000
#define SJA1105_SIZE_PTP_CMD		4

/* PTPSYNCTS has no interrupt or update mechanism, because the intended
 * hardware use case is for the timestamp to be collected synchronously,
 * immediately after the CAS_MASTER SJA1105 switch has performed a CASSYNC
 * one-shot toggle (no return to level) on the PTP_CLK pin. When used as a
 * generic extts source, the PTPSYNCTS register needs polling and a comparison
 * with the old value. The polling interval is configured as the Nyquist rate
 * of a signal with 50% duty cycle and 1Hz frequency, which is sadly all that
 * this hardware can do (but may be enough for some setups). Anything of higher
 * frequency than 1 Hz will be lost, since there is no timestamp FIFO.
 */
#define SJA1105_EXTTS_INTERVAL		(HZ / 6)

/*            This range is actually +/- SJA1105_MAX_ADJ_PPB
 *            divided by 1000 (ppb -> ppm) and with a 16-bit
 *            "fractional" part (actually fixed point).
 *                                    |
 *                                    v
 * Convert scaled_ppm from the +/- ((10^6) << 16) range
 * into the +/- (1 << 31) range.
 *
 * This forgoes a "ppb" numeric representation (up to NSEC_PER_SEC)
 * and defines the scaling factor between scaled_ppm and the actual
 * frequency adjustments of the PHC.
 *
 *   ptpclkrate = scaled_ppm * 2^31 / (10^6 * 2^16)
 *   simplifies to
 *   ptpclkrate = scaled_ppm * 2^9 / 5^6
 */
#define SJA1105_CC_MULT_NUM		(1 << 9)
#define SJA1105_CC_MULT_DEM		15625
#define SJA1105_CC_MULT			0x80000000

enum sja1105_ptp_clk_mode {
	PTP_ADD_MODE = 1,
	PTP_SET_MODE = 0,
};

#define extts_to_data(t) \
		container_of((t), struct sja1105_ptp_data, extts_timer)
#define ptp_caps_to_data(d) \
		container_of((d), struct sja1105_ptp_data, caps)
#define ptp_data_to_sja1105(d) \
		container_of((d), struct sja1105_private, ptp_data)

/* Must be called only with priv->tagger_data.state bit
 * SJA1105_HWTS_RX_EN cleared
 */
static int sja1105_change_rxtstamping(struct sja1105_private *priv,
				      bool on)
{
	struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
	struct sja1105_general_params_entry *general_params;
	struct sja1105_table *table;

	table = &priv->static_config.tables[BLK_IDX_GENERAL_PARAMS];
	general_params = table->entries;
	general_params->send_meta1 = on;
	general_params->send_meta0 = on;

	/* Initialize the meta state machine to a known state */
	if (priv->tagger_data.stampable_skb) {
		kfree_skb(priv->tagger_data.stampable_skb);
		priv->tagger_data.stampable_skb = NULL;
	}
	ptp_cancel_worker_sync(ptp_data->clock);
	skb_queue_purge(&ptp_data->skb_rxtstamp_queue);

	return sja1105_static_config_reload(priv, SJA1105_RX_HWTSTAMPING);
}

int sja1105_hwtstamp_set(struct dsa_switch *ds, int port, struct ifreq *ifr)
{
	struct sja1105_private *priv = ds->priv;
	struct hwtstamp_config config;
	bool rx_on;
	int rc;

	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
		return -EFAULT;

	switch (config.tx_type) {
	case HWTSTAMP_TX_OFF:
		priv->ports[port].hwts_tx_en = false;
		break;
	case HWTSTAMP_TX_ON:
		priv->ports[port].hwts_tx_en = true;
		break;
	default:
		return -ERANGE;
	}

	switch (config.rx_filter) {
	case HWTSTAMP_FILTER_NONE:
		rx_on = false;
		break;
	default:
		rx_on = true;
		break;
	}

	if (rx_on != test_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state)) {
		clear_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state);

		rc = sja1105_change_rxtstamping(priv, rx_on);
		if (rc < 0) {
			dev_err(ds->dev,
				"Failed to change RX timestamping: %d\n", rc);
			return rc;
		}
		if (rx_on)
			set_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state);
	}

	if (copy_to_user(ifr->ifr_data, &config, sizeof(config)))
		return -EFAULT;
	return 0;
}

int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr)
{
	struct sja1105_private *priv = ds->priv;
	struct hwtstamp_config config;

	config.flags = 0;
	if (priv->ports[port].hwts_tx_en)
		config.tx_type = HWTSTAMP_TX_ON;
	else
		config.tx_type = HWTSTAMP_TX_OFF;
	if (test_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state))
		config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
	else
		config.rx_filter = HWTSTAMP_FILTER_NONE;

	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
		-EFAULT : 0;
}

int sja1105_get_ts_info(struct dsa_switch *ds, int port,
			struct ethtool_ts_info *info)
{
	struct sja1105_private *priv = ds->priv;
	struct sja1105_ptp_data *ptp_data = &priv->ptp_data;

	/* Called during cleanup */
	if (!ptp_data->clock)
		return -ENODEV;

	info->so_timestamping = SOF_TIMESTAMPING_TX_HARDWARE |
				SOF_TIMESTAMPING_RX_HARDWARE |
				SOF_TIMESTAMPING_RAW_HARDWARE;
	info->tx_types = (1 << HWTSTAMP_TX_OFF) |
			 (1 << HWTSTAMP_TX_ON);
	info->rx_filters = (1 << HWTSTAMP_FILTER_NONE) |
			   (1 << HWTSTAMP_FILTER_PTP_V2_L2_EVENT);
	info->phc_index = ptp_clock_index(ptp_data->cloc