net: dsa: sja1105: Implement state machine for TAS with PTP clock source

Tested using the following bash script and the tc from iproute2-next:

	#!/bin/bash

	set -e -u -o pipefail

	NSEC_PER_SEC="1000000000"

	gatemask() {
		local tc_list="$1"
		local mask=0

		for tc in ${tc_list}; do
			mask=$((${mask} | (1 << ${tc})))
		done

		printf "%02x" ${mask}
	}

	if ! systemctl is-active --quiet ptp4l; then
		echo "Please start the ptp4l service"
		exit
	fi

	now=$(phc_ctl /dev/ptp1 get | gawk '/clock time is/ { print $5; }')
	# Phase-align the base time to the start of the next second.
	sec=$(echo "${now}" | gawk -F. '{ print $1; }')
	base_time="$(((${sec} + 1) * ${NSEC_PER_SEC}))"

	tc qdisc add dev swp5 parent root handle 100 taprio \
		num_tc 8 \
		map 0 1 2 3 5 6 7 \
		queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
		base-time ${base_time} \
		sched-entry S $(gatemask 7) 100000 \
		sched-entry S $(gatemask "0 1 2 3 4 5 6") 400000 \
		clockid CLOCK_TAI flags 2

The "state machine" is a workqueue invoked after each manipulation
command on the PTP clock (reset, adjust time, set time, adjust
frequency) which checks over the state of the time-aware scheduler.
So it is not monitored periodically, only in reaction to a PTP command
typically triggered from a userspace daemon (linuxptp). Otherwise there
is no reason for things to go wrong.

Now that the timecounter/cyclecounter has been replaced with hardware
operations on the PTP clock, the TAS Kconfig now depends upon PTP and
the standalone clocksource operating mode has been removed.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_spi.c

@@ -539,9 +539,11 @@ static struct sja1105_regs sja1105et_regs = {
 	.rmii_ref_clk = {0x100015, 0x10001C, 0x100023, 0x10002A, 0x100031},
 	.rmii_ext_tx_clk = {0x100018, 0x10001F, 0x100026, 0x10002D, 0x100034},
 	.ptpegr_ts = {0xC0, 0xC2, 0xC4, 0xC6, 0xC8},
+	.ptpschtm = 0x12, /* Spans 0x12 to 0x13 */
 	.ptp_control = 0x17,
 	.ptpclkval = 0x18, /* Spans 0x18 to 0x19 */
 	.ptpclkrate = 0x1A,
+	.ptpclkcorp = 0x1D,
 };
 
 static struct sja1105_regs sja1105pqrs_regs = {
@@ -569,9 +571,11 @@ static struct sja1105_regs sja1105pqrs_regs = {
 	.rmii_ext_tx_clk = {0x100017, 0x10001D, 0x100023, 0x100029, 0x10002F},
 	.qlevel = {0x604, 0x614, 0x624, 0x634, 0x644},
 	.ptpegr_ts = {0xC0, 0xC4, 0xC8, 0xCC, 0xD0},
+	.ptpschtm = 0x13, /* Spans 0x13 to 0x14 */
 	.ptp_control = 0x18,
 	.ptpclkval = 0x19,
 	.ptpclkrate = 0x1B,
+	.ptpclkcorp = 0x1E,
 };
 
 struct sja1105_info sja1105e_info = {