s390/time: remove ETR support

The External-Time-Reference (ETR) clock synchronization interface has
been superseded by Server-Time-Protocol (STP). Remove the outdated
ETR interface.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 988 deletions

diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 1a27d4d08b43..4e9949800562 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -46,7 +46,7 @@
 #include <asm/irq.h>
 #include <asm/irq_regs.h>
 #include <asm/vtimer.h>
-#include <asm/etr.h>
+#include <asm/stp.h>
 #include <asm/cio.h>
 #include "entry.h"
 
@@ -189,20 +189,16 @@ static void clock_comparator_interrupt(struct ext_code ext_code,
 		set_clock_comparator(S390_lowcore.clock_comparator);
 }
 
-static void etr_timing_alert(struct etr_irq_parm *);
 static void stp_timing_alert(struct stp_irq_parm *);
 
 static void timing_alert_interrupt(struct ext_code ext_code,
 				   unsigned int param32, unsigned long param64)
 {
 	inc_irq_stat(IRQEXT_TLA);
-	if (param32 & 0x00c40000)
-		etr_timing_alert((struct etr_irq_parm *) &param32);
 	if (param32 & 0x00038000)
 		stp_timing_alert((struct stp_irq_parm *) &param32);
 }
 
-static void etr_reset(void);
 static void stp_reset(void);
 
 void read_persistent_clock64(struct timespec64 *ts)
@@ -302,7 +298,6 @@ void update_vsyscall_tz(void)
 void __init time_init(void)
 {
 	/* Reset time synchronization interfaces. */
-	etr_reset();
 	stp_reset();
 
 	/* request the clock comparator external interrupt */
@@ -449,301 +444,6 @@ static void __init time_init_wq(void)
 	time_sync_wq = create_singlethread_workqueue("timesync");
 }
 
-/*
- * External Time Reference (ETR) code.
- */
-static int etr_port0_online;
-static int etr_port1_online;
-static int etr_steai_available;
-
-static int __init early_parse_etr(char *p)
-{
-	if (strncmp(p, "off", 3) == 0)
-		etr_port0_online = etr_port1_online = 0;
-	else if (strncmp(p, "port0", 5) == 0)
-		etr_port0_online = 1;
-	else if (strncmp(p, "port1", 5) == 0)
-		etr_port1_online = 1;
-	else if (strncmp(p, "on", 2) == 0)
-		etr_port0_online = etr_port1_online = 1;
-	return 0;
-}
-early_param("etr", early_parse_etr);
-
-enum etr_event {
-	ETR_EVENT_PORT0_CHANGE,
-	ETR_EVENT_PORT1_CHANGE,
-	ETR_EVENT_PORT_ALERT,
-	ETR_EVENT_SYNC_CHECK,
-	ETR_EVENT_SWITCH_LOCAL,
-	ETR_EVENT_UPDATE,
-};
-
-/*
- * Valid bit combinations of the eacr register are (x = don't care):
- * e0 e1 dp p0 p1 ea es sl
- *  0  0  x  0	0  0  0  0  initial, disabled state
- *  0  0  x  0	1  1  0  0  port 1 online
- *  0  0  x  1	0  1  0  0  port 0 online
- *  0  0  x  1	1  1  0  0  both ports online
- *  0  1  x  0	1  1  0  0  port 1 online and usable, ETR or PPS mode
- *  0  1  x  0	1  1  0  1  port 1 online, usable and ETR mode
- *  0  1  x  0	1  1  1  0  port 1 online, usable, PPS mode, in-sync
- *  0  1  x  0	1  1  1  1  port 1 online, usable, ETR mode, in-sync
- *  0  1  x  1	1  1  0  0  both ports online, port 1 usable
- *  0  1  x  1	1  1  1  0  both ports online, port 1 usable, PPS mode, in-sync
- *  0  1  x  1	1  1  1  1  both ports online, port 1 usable, ETR mode, in-sync
- *  1  0  x  1	0  1  0  0  port 0 online and usable, ETR or PPS mode
- *  1  0  x  1	0  1  0  1  port 0 online, usable and ETR mode
- *  1  0  x  1	0  1  1  0  port 0 online, usable, PPS mode, in-sync
- *  1  0  x  1	0  1  1  1  port 0 online, usable, ETR mode, in-sync
- *  1  0  x  1	1  1  0  0  both ports online, port 0 usable
- *  1  0  x  1	1  1  1  0  both ports online, port 0 usable, PPS mode, in-sync
- *  1  0  x  1	1  1  1  1  both ports online, port 0 usable, ETR mode, in-sync
- *  1  1  x  1	1  1  1  0  both ports online & usable, ETR, in-sync
- *  1  1  x  1	1  1  1  1  both ports online & usable, ETR, in-sync
- */
-static struct etr_eacr etr_eacr;
-static u64 etr_tolec;			/* time of last eacr update */
-static struct etr_aib etr_port0;
-static int etr_port0_uptodate;
-static struct etr_aib etr_port1;
-static int etr_port1_uptodate;
-static unsigned long etr_events;
-static struct timer_list etr_timer;
-
-static void etr_timeout(unsigned long dummy);
-static void etr_work_fn(struct work_struct *work);
-static DEFINE_MUTEX(etr_work_mutex);
-static DECLARE_WORK(etr_work, etr_work_fn);
-
-/*
- * Reset ETR attachment.
- */
-static void etr_reset(void)
-{
-	etr_eacr =  (struct etr_eacr) {
-		.e0 = 0, .e1 = 0, ._pad0 = 4, .dp = 0,
-		.p0 = 0, .p1 = 0, ._pad1 = 0, .ea = 0,
-		.es = 0, .sl = 0 };
-	if (etr_setr(&etr_eacr) == 0) {
-		etr_tolec = get_tod_clock();
-		set_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags);
-		if (etr_port0_online && etr_port1_online)
-			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
-	} else if (etr_port0_online || etr_port1_online) {
-		pr_warn("The real or virtual hardware system does not provide an ETR interface\n");
-		etr_port0_online = etr_port1_online = 0;
-	}
-}
-
-static int __init etr_init(void)
-{
-	struct etr_aib aib;
-
-	if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
-		return 0;
-	time_init_wq();
-	/* Check if this machine has the steai instruction. */
-	if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
-		etr_steai_available = 1;
-	setup_timer(&etr_timer, etr_timeout, 0UL);
-	if (etr_port0_online) {
-		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
-		queue_work(time_sync_wq, &etr_work);
-	}
-	if (etr_port1_online) {
-		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
-		queue_work(time_sync_wq, &etr_work);
-	}
-	return 0;
-}
-
-arch_initcall(etr_init);
-
-/*
- * Two sorts of ETR machine checks. The architecture reads:
- * "When a machine-check niterruption occurs and if a switch-to-local or
- *  ETR-sync-check interrupt request is pending but disabled, this pending
- *  disabled interruption request is indicated and is cleared".
- * Which means that we can get etr_switch_to_local events from the machine
- * check handler although the interruption condition is disabled. Lovely..
- */
-
-/*
- * Switch to local machine check. This is called when the last usable
- * ETR port goes inactive. After switch to local the clock is not in sync.
- */
-int etr_switch_to_local(void)
-{
-	if (!etr_eacr.sl)
-		return 0;
-	disable_sync_clock(NULL);
-	if (!test_and_set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events)) {
-		etr_eacr.es = etr_eacr.sl = 0;
-		etr_setr(&etr_eacr);
-		return 1;
-	}
-	return 0;
-}
-
-/*
- * ETR sync check machine check. This is called when the ETR OTE and the
- * local clock OTE are farther apart than the ETR sync check tolerance.
- * After a ETR sync check the clock is not in sync. The machine check
- * is broadcasted to all cpus at the same time.
- */
-int etr_sync_check(void)
-{
-	if (!etr_eacr.es)
-		return 0;
-	disable_sync_clock(NULL);
-	if (!test_and_set_bit(ETR_EVENT_SYNC_CHECK, &etr_events)) {
-		etr_eacr.es = 0;
-		etr_setr(&etr_eacr);
-		return 1;
-	}
-	return 0;
-}
-
-void etr_queue_work(void)
-{
-	queue_work(time_sync_wq, &etr_work);
-}
-
-/*
- * ETR timing alert. There are two causes:
- * 1) port state change, check the usability of the port
- * 2) port alert, one of the ETR-data-validity bits (v1-v2 bits of the
- *    sldr-status word) or ETR-data word 1 (edf1) or ETR-data word 3 (edf3)
- *    or ETR-data word 4 (edf4) has changed.
- */
-static void etr_timing_alert(struct etr_irq_parm *intparm)
-{
-	if (intparm->pc0)
-		/* ETR port 0 state change. */
-		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
-	if (intparm->pc1)
-		/* ETR port 1 state change. */
-		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
-	if (intparm->eai)
-		/*
-		 * ETR port alert on either port 0, 1 or both.
-		 * Both ports are not up-to-date now.
-		 */
-		set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
-	queue_work(time_sync_wq, &etr_work);
-}
-
-static void etr_timeout(unsigned long dummy)
-{
-	set_bit(ETR_EVENT_UPDATE, &etr_events);
-	queue_work(time_sync_wq, &etr_work);
-}
-
-/*
- * Check if the etr mode is pss.
- */
-static inline int etr_mode_is_pps(struct etr_eacr eacr)
-{
-	return eacr.es && !eacr.sl;
-}
-
-/*
- * Check if the etr mode is etr.
- */
-static inline int etr_mode_is_etr(struct etr_eacr eacr)
-{
-	return eacr.es && eacr.sl;
-}
-
-/*
- * Check if the port can be used for TOD synchronization.
- * For PPS mode the port has to receive OTEs. For ETR mode
- * the port has to receive OTEs, the ETR stepping bit has to
- * be zero and the validity bits for data frame 1, 2, and 3
- * have to be 1.
- */
-static int etr_port_valid(struct etr_aib *aib, int port)
-{
-	unsigned int psc;
-
-	/* Check that this port is receiving OTEs. */
-	if (aib->tsp == 0)
-		return 0;
-
-	psc = port ? aib->esw.psc1 : aib->esw.psc0;
-	if (psc == etr_lpsc_pps_mode)
-		return 1;
-	if (psc == etr_lpsc_operational_step)
-		return !aib->esw.y && aib->slsw.v1 &&
-			aib->slsw.v2 && aib->slsw.v3;
-	return 0;
-}
-
-/*
- * Check if two ports are on the same network.
- */
-static int etr_compare_network(struct etr_aib *aib1, struct etr_aib *aib2)
-{
-	// FIXME: any other fields we have to compare?
-	return aib1->edf1.net_id == aib2->edf1.net_id;
-}
-
-/*
- * Wrapper for etr_stei that converts physical port states
- * to logical port states to be consistent with the output
- * of stetr (see etr_psc vs. etr_lpsc).
- */
-static void etr_steai_cv(struct etr_aib *aib, unsigned int func)
-{
-	BUG_ON(etr_steai(aib, func) != 0);
-	/* Convert port state to logical port state. */
-	if (aib->esw.psc0 == 1)
-		aib->esw.psc0 = 2;
-	else if (aib->esw.psc0 == 0 && aib->esw.p == 0)
-		aib->esw.psc0 = 1;
-	if (aib->esw.psc1 == 1)
-		aib->esw.psc1 = 2;
-	else if (aib->esw.psc1 == 0 && aib->esw.p == 1)
-		aib->esw.psc1 = 1;
-}
-
-/*
- * Check if the aib a2 is still connected to the same attachment as
- * aib a1, the etv values differ by one and a2 is valid.
- */
-static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
-{
-	int state_a1, state_a2;
-
-	/* Paranoia check: e0/e1 should better be the same. */
-	if (a1->esw.eacr.e0 != a2->esw.eacr.e0 ||
-	    a1->esw.eacr.e1 != a2->esw.eacr.e1)
-		return 0;
-
-	/* Still connected to the same etr ? */
-	state_a1 = p ? a1->esw.psc1 : a1->esw.psc0;
-	state_a2 = p ? a2->esw.psc1 : a2->esw.psc0;
-	if (state_a1 == etr_lpsc_operational_step) {
-		if (state_a2 != etr_lpsc_operational_step ||
-		    a1->edf1.net_id != a2->edf1.net_id ||
-		    a1->edf1.etr_id != a2->edf1.etr_id ||
-		    a1->edf1.etr_pn != a2->edf1.etr_pn)
-			return 0;
-	} else if (state_a2 != etr_lpsc_pps_mode)
-		return 0;
-
-	/* The ETV value of a2 needs to be ETV of a1 + 1. */
-	if (a1->edf2.etv + 1 != a2->edf2.etv)
-		return 0;
-
-	if (!etr_port_valid(a2, p))
-		return 0;
-
-	return 1;
-}
-
 struct clock_sync_data {
 	atomic_t cpus;
 	int in_sync;
@@ -781,693 +481,6 @@ static void clock_sync_cpu(struct clock_sync_data *sync)
 }
 
 /*
- * Sync the TOD clock using the port referred to by aibp. This port
- * has to be enabled and the other port has to be disabled. The
- * last eacr update has to be more than 1.6 seconds in the past.
- */
-static int etr_sync_clock(void *data)
-{
-	static int first;
-	unsigned long long clock, old_clock, clock_delta, delay, delta;
-	struct clock_sync_data *etr_sync;
-	struct etr_aib *sync_port, *aib;
-	struct ptff_qto qto;
-	int port;
-	int rc;
-
-	etr_sync = data;
-
-	if (xchg(&first, 1) == 1) {
-		/* Slave */
-		clock_sync_cpu(etr_sync);
-		return 0;
-	}
-
-	/* Wait until all other cpus entered the sync function. */
-	while (atomic_read(&etr_sync->cpus) != 0)
-		cpu_relax();
-
-	port = etr_sync->etr_port;
-	aib = etr_sync->etr_aib;
-	sync_port = (port == 0) ? &etr_port0 : &etr_port1;
-	enable_sync_clock();
-
-	/* Set clock to next OTE. */
-	__ctl_set_bit(14, 21);
-	__ctl_set_bit(0, 29);
-	clock = ((unsigned long long) (aib->edf2.etv + 1)) << 32;
-	old_clock = get_tod_clock();
-	if (set_tod_clock(clock) == 0) {
-		__udelay(1);	/* Wait for the clock to start. */
-		__ctl_clear_bit(0, 29);
-		__ctl_clear_bit(14, 21);
-		etr_stetr(aib);
-		/* Adjust Linux timing variables. */
-		delay = (unsigned long long)
-			(aib->edf2.etv - sync_port->edf2.etv) << 32;
-		delta = adjust_time(old_clock, clock, delay);
-		clock_delta = clock - old_clock;
-		atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0,
-					   &clock_delta);
-		etr_sync->fixup_cc = delta;
-		fixup_clock_comparator(delta);
-		/* Verify that the clock is properly set. */
-		if (!etr_aib_follows(sync_port, aib, port)) {
-			/* Didn't work. */
-			disable_sync_clock(NULL);
-			etr_sync->in_sync = -EAGAIN;
-			rc = -EAGAIN;
-		} else {
-			if (ptff_query(PTFF_QTO) &&
-			    ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
-				/* Update LPAR offset */
-				lpar_offset = qto.tod_epoch_difference;
-			etr_sync->in_sync = 1;
-			rc = 0;
-		}
-	} else {
-		/* Could not set the clock ?!? */
-		__ctl_clear_bit(0, 29);
-		__ctl_clear_bit(14, 21);
-		disable_sync_clock(NULL);
-		etr_sync->in_sync = -EAGAIN;
-		rc = -EAGAIN;
-	}
-	xchg(&first, 0);
-	return rc;
-}
-
-static int etr_sync_clock_stop(struct etr_aib *aib, int port)
-{
-	struct clock_sync_data etr_sync;
-	struct etr_aib *sync_port;
-	int follows;
-	int rc;
-
-	/* Check if the current aib is adjacent to the sync port aib. */
-	sync_port = (port == 0) ? &etr_port0 : &etr_port1;
-	follows = etr_aib_follows(sync_port, aib, port);
-	memcpy(sync_port, aib, sizeof(*aib));
-	if (!follows)
-		return -EAGAIN;
-	memset(&etr_sync, 0, sizeof(etr_sync));
-	etr_sync.etr_aib = aib;
-	etr_sync.etr_port = port;
-	get_online_cpus();
-	atomic_set(&etr_sync.cpus, num_online_cpus() - 1);
-	rc = stop_machine(etr_sync_clock, &etr_sync, cpu_online_mask);
-	put_online_cpus();
-	return rc;
-}
-
-/*
- * Handle the immediate effects of the different events.
- * The port change event is used for online/offline changes.
- */
-static struct etr_eacr etr_handle_events(struct etr_eacr eacr)
-{
-	if (test_and_clear_bit(ETR_EVENT_SYNC_CHECK, &etr_events))
-		eacr.es = 0;
-	if (test_and_clear_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events))
-		eacr.es = eacr.sl = 0;
-	if (test_and_clear_bit(ETR_EVENT_PORT_ALERT, &etr_events))
-		etr_port0_uptodate = etr_port1_uptodate = 0;
-
-	if (test_and_clear_bit(ETR_EVENT_PORT0_CHANGE, &etr_events)) {
-		if (eacr.e0)
-			/*
-			 * Port change of an enabled port. We have to
-			 * assume that this can have caused an stepping
-			 * port switch.
-			 */
-			etr_tolec = get_tod_clock();
-		eacr.p0 = etr_port0_online;
-		if (!eacr.p0)
-			eacr.e0 = 0;
-		etr_port0_uptodate = 0;
-	}
-	if (test_and_clear_bit(ETR_EVENT_PORT1_CHANGE, &etr_events)) {
-		if (eacr.e1)
-			/*
-			 * Port change of an enabled port. We have to
-			 * assume that this can have caused an stepping
-			 * port switch.
-			 */
-			etr_tolec = get_tod_clock();
-		eacr.p1 = etr_port1_online;
-		if (!eacr.p1)
-			eacr.e1 = 0;
-		etr_port1_uptodate = 0;
-	}
-	clear_bit(ETR_EVENT_UPDATE, &etr_events);
-	return eacr;
-}
-
-/*
- * Set up a timer that expires after the etr_tolec + 1.6 seconds if
- * one of the ports needs an update.
- */
-static void etr_set_tolec_timeout(unsigned long long now)
-{
-	unsigned long micros;
-
-	if ((!etr_eacr.p0 || etr_port0_uptodate) &&
-	    (!etr_eacr.p1 || etr_port1_uptodate))
-		return;
-	micros = (now > etr_tolec) ? ((now - etr_tolec) >> 12) : 0;
-	micros = (micros > 1600000) ? 0 : 1600000 - micros;
-	mod_timer(&etr_timer, jiffies + (micros * HZ) / 1000000 + 1);
-}
-
-/*
- * Set up a time that expires after 1/2 second.
- */
-static void etr_set_sync_timeout(void)
-{
-	mod_timer(&etr_timer, jiffies + HZ/2);
-}
-
-/*
- * Update the aib information for one or both ports.
- */
-static struct etr_eacr etr_handle_update(struct etr_aib *aib,
-					 struct etr_eacr eacr)
-{
-	/* With both ports disabled the aib information is useless. */
-	if (!eacr.e0 && !eacr.e1)
-		return eacr;
-
-	/* Update port0 or port1 with aib stored in etr_work_fn. */
-	if (aib->esw.q == 0) {
-		/* Information for port 0 stored. */
-		if (eacr.p0 && !etr_port0_uptodate) {
-			etr_port0 = *aib;
-			if (etr_port0_online)
-				etr_port0_uptodate = 1;
-		}
-	} else {
-		/* Information for port 1 stored. */
-		if (eacr.p1 && !etr_port1_uptodate) {
-			etr_port1 = *aib;
-			if (etr_port0_online)
-				etr_port1_uptodate = 1;
-		}
-	}
-
-	/*
-	 * Do not try to get the alternate port aib if the clock
-	 * is not in sync yet.
-	 */
-	if (!eacr.es || !check_sync_clock())
-		return eacr;
-
-	/*
-	 * If steai is available we can get the information about
-	 * the other port immediately. If only stetr is available the
-	 * data-port bit toggle has to be used.
-	 */
-	if (etr_steai_available) {
-		if (eacr.p0 && !etr_port0_uptodate) {
-			etr_steai_cv(&etr_port0, ETR_STEAI_PORT_0);
-			etr_port0_uptodate = 1;
-		}
-		if (eacr.p1 && !etr_port1_uptodate) {
-			etr_steai_cv(&etr_port1, ETR_STEAI_PORT_1);
-			etr_port1_uptodate = 1;
-		}
-	} else {
-		/*
-		 * One port was updated above, if the other
-		 * port is not uptodate toggle dp bit.
-		 */
-		if ((eacr.p0 && !etr_port0_uptodate) ||
-		    (eacr.p1 && !etr_port1_uptodate))
-			eacr.dp ^= 1;
-		else
-			eacr.dp = 0;
-	}
-	return eacr;
-}
-
-/*
- * Write new etr control register if it differs from the current one.
- * Return 1 if etr_tolec has been updated as well.
- */
-static void etr_update_eacr(struct etr_eacr eacr)
-{
-	int dp_changed;
-
-	if (memcmp(&etr_eacr, &eacr, sizeof(eacr)) == 0)
-		/* No change, return. */
-		return;
-	/*
-	 * The disable of an active port of the change of the data port
-	 * bit can/will cause a change in the data port.
-	 */
-	dp_changed = etr_eacr.e0 > eacr.e0 || etr_eacr.e1 > eacr.e1 ||
-		(etr_eacr.dp ^ eacr.dp) != 0;
-	etr_eacr = eacr;
-	etr_setr(&etr_eacr);
-	if (dp_changed)
-		etr_tolec = get_tod_clock();
-}
-
-/*
- * ETR work. In this function you'll find the main logic. In
- * particular this is the only function that calls etr_update_eacr(),
- * it "controls" the etr control register.
- */
-static void etr_work_fn(struct work_struct *work)
-{
-	unsigned long long now;
-	struct etr_eacr eacr;
-	struct etr_aib aib;
-	int sync_port;
-
-	/* prevent multiple execution. */
-	mutex_lock(&etr_work_mutex);
-
-	/* Create working copy of etr_eacr. */
-	eacr = etr_eacr;
-
-	/* Check for the different events and their immediate effects. */
-	eacr = etr_handle_events(eacr);
-
-	/* Check if ETR is supposed to be active. */
-	eacr.ea = eacr.p0 || eacr.p1;
-	if (!eacr.ea) {
-		/* Both ports offline. Reset everything. */
-		eacr.dp = eacr.es = eacr.sl = 0;
-		on_each_cpu(disable_sync_clock, NULL, 1);
-		del_timer_sync(&etr_timer);
-		etr_update_eacr(eacr);
-		goto out_unlock;
-	}
-
-	/* Store aib to get the current ETR status word. */
-	BUG_ON(etr_stetr(&aib) != 0);
-	etr_port0.esw = etr_port1.esw = aib.esw;	/* Copy status word. */
-	now = get_tod_clock();
-
-	/*
-	 * Update the port information if the last stepping port change
-	 * or data port change is older than 1.6 seconds.
-	 */
-	if (now >= etr_tolec + (1600000 << 12))
-		eacr = etr_handle_update(&aib, eacr);
-
-	/*
-	 * Select ports to enable. The preferred synchronization mode is PPS.
-	 * If a port can be enabled depends on a number of things:
-	 * 1) The port needs to be online and uptodate. A port is not
-	 *    disabled just because it is not uptodate, but it is only
-	 *    enabled if it is uptodate.
-	 * 2) The port needs to have the same mode (pps / etr).
-	 * 3) The port needs to be usable -> etr_port_valid() == 1
-	 * 4) To enable the second port the clock needs to be in sync.
-	 * 5) If both ports are useable and are ETR ports, the network id
-	 *    has to be the same.
-	 * The eacr.sl bit is used to indicate etr mode vs. pps mode.
-	 */
-	if (eacr.p0 && aib.esw.psc0 == etr_lpsc_pps_mode) {
-		eacr.sl = 0;
-		eacr.e0 = 1;
-		if (!etr_mode_is_pps(etr_eacr))
-			eacr.es = 0;
-		if (!eacr.es || !eacr.p1 || aib.esw.psc1 != etr_lpsc_pps_mode)
-			eacr.e1 = 0;
-		// FIXME: uptodate checks ?
-		else if (etr_port0_uptodate && etr_port1_uptodate)
-			eacr.e1 = 1;
-		sync_port = (etr_port0_uptodate &&
-			     etr_port_valid(&etr_port0, 0)) ? 0 : -1;
-	} else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_pps_mode) {
-		eacr.sl = 0;
-		eacr.e0 = 0;
-		eacr.e1 = 1;
-		if (!etr_mode_is_pps(etr_eacr))
-			eacr.es = 0;
-		sync_port = (etr_port1_uptodate &&
-			     etr_port_valid(&etr_port1, 1)) ? 1 : -1;
-	} else if (eacr.p0 && aib.esw.psc0 == etr_lpsc_operational_step) {
-		eacr.sl = 1;
-		eacr.e0 = 1;
-		if (!etr_mode_is_etr(etr_eacr))
-			eacr.es = 0;
-		if (!eacr.es || !eacr.p1 ||
-		    aib.esw.psc1 != etr_lpsc_operational_alt)
-			eacr.e1 = 0;
-		else if (etr_port0_uptodate && etr_port1_uptodate &&
-			 etr_compare_network(&etr_port0, &etr_port1))
-			eacr.e1 = 1;
-		sync_port = (etr_port0_uptodate &&
-			     etr_port_valid(&etr_port0, 0)) ? 0 : -1;
-	} else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_operational_step) {
-		eacr.sl = 1;
-		eacr.e0 = 0;
-		eacr.e1 = 1;
-		if (!etr_mode_is_etr(etr_eacr))
-			eacr.es = 0;
-		sync_port = (etr_port1_uptodate &&
-			     etr_port_valid(&etr_port1, 1)) ? 1 : -1;
-	} else {
-		/* Both ports not usable. */
-		eacr.es = eacr.sl = 0;
-		sync_port = -1;
-	}
-
-	/*
-	 * If the clock is in sync just update the eacr and return.
-	 * If there is no valid sync port wait for a port update.
-	 */
-	if ((eacr.es && check_sync_clock()) || sync_port < 0) {
-		etr_update_eacr(eacr);
-		etr_set_tolec_timeout(now);
-		goto out_unlock;
-	}
-
-	/*
-	 * Prepare control register for clock syncing
-	 * (reset data port bit, set sync check control.
-	 */
-	eacr.dp = 0;
-	eacr.es = 1;
-
-	/*
-	 * Update eacr and try to synchronize the clock. If the update
-	 * of eacr caused a stepping port switch (or if we have to
-	 * assume that a stepping port switch has occurred) or the
-	 * clock syncing failed, reset the sync check control bit
-	 * and set up a timer to try again after 0.5 seconds
-	 */
-	etr_update_eacr(eacr);
-	if (now < etr_tolec + (1600000 << 12) ||
-	    etr_sync_clock_stop(&aib, sync_port) != 0) {
-		/* Sync failed. Try again in 1/2 second. */
-		eacr.es = 0;
-		etr_update_eacr(eacr);
-		etr_set_sync_timeout();
-	} else
-		etr_set_tolec_timeout(now);
-out_unlock:
-	mutex_unlock(&etr_work_mutex);
-}
-
-/*
- * Sysfs interface functions
- */
-static struct bus_type etr_subsys = {
-	.name		= "etr",
-	.dev_name	= "etr",
-};
-
-static struct device etr_port0_dev = {
-	.id	= 0,
-	.bus	= &etr_subsys,
-};
-
-static struct device etr_port1_dev = {
-	.id	= 1,
-	.bus	= &etr_subsys,
-};
-
-/*
- * ETR subsys attributes
- */
-static ssize_t etr_stepping_port_show(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
-{
-	return sprintf(buf, "%i\n", etr_port0.esw.p);
-}
-
-static DEVICE_ATTR(stepping_port, 0400, etr_stepping_port_show, NULL);
-
-static ssize_t etr_stepping_mode_show(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
-{
-	char *mode_str;
-
-	if (etr_mode_is_pps(etr_eacr))
-		mode_str = "pps";
-	else if (etr_mode_is_etr(etr_eacr))
-		mode_str = "etr";
-	else
-		mode_str = "local";
-	return sprintf(buf, "%s\n", mode_str);
-}
-
-static DEVICE_ATTR(stepping_mode, 0400, etr_stepping_mode_show, NULL);
-
-/*
- * ETR port attributes
- */
-static inline struct etr_aib *etr_aib_from_dev(struct device *dev)
-{
-	if (dev == &etr_port0_dev)
-		return etr_port0_online ? &etr_port0 : NULL;
-	else
-		return etr_port1_online ? &etr_port1 : NULL;
-}
-
-static ssize_t etr_online_show(struct device *dev,
-				struct device_attribute *attr,
-				char *buf)
-{
-	unsigned int online;
-
-	online = (dev == &etr_port0_dev) ? etr_port0_online : etr_port1_online;
-	return sprintf(buf, "%i\n", online);
-}
-
-static ssize_t etr_online_store(struct device *dev,
-				struct device_attribute *attr,
-				const char *buf, size_t count)
-{
-	unsigned int value;
-
-	value = simple_strtoul(buf, NULL, 0);
-	if (value != 0 && value != 1)
-		return -EINVAL;
-	if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
-		return -EOPNOTSUPP;
-	mutex_lock(&clock_sync_mutex);
-	if (dev == &etr_port0_dev) {
-		if (etr_port0_online == value)
-			goto out;	/* Nothing to do. */
-		etr_port0_online = value;
-		if (etr_port0_online && etr_port1_online)
-			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
-		else
-			clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
-		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
-		queue_work(time_sync_wq, &etr_work);
-	} else {
-		if (etr_port1_online == value)
-			goto out;	/* Nothing to do. */
-		etr_port1_online = value;
-		if (etr_port0_online && etr_port1_online)
-			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
-		else
-			clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
-		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
-		queue_work(time_sync_wq, &etr_work);
-	}
-out:
-	mutex_unlock(&clock_sync_mutex);
-	return count;
-}
-
-static DEVICE_ATTR(online, 0600, etr_online_show, etr_online_store);
-
-static ssize_t etr_stepping_control_show(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
-{
-	return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
-		       etr_eacr.e0 : etr_eacr.e1);
-}
-
-static DEVICE_ATTR(stepping_control, 0400, etr_stepping_control_show, NULL);
-
-static ssize_t etr_mode_code_show(struct device *dev,
-				struct device_attribute *attr, char *buf)
-{
-	if (!etr_port0_online && !etr_port1_online)
-		/* Status word is not uptodate if both ports are offline. */
-		return -ENODATA;
-	return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
-		       etr_port0.esw.psc0 : etr_port0.esw.psc1);
-}
-
-static DEVICE_ATTR(state_code, 0400, etr_mode_code_show, NULL);
-
-static ssize_t etr_untuned_show(struct device *dev,
-				struct device_attribute *attr, char *buf)
-{
-	struct etr_aib *aib = etr_aib_from_dev(dev);
-
-	if (!aib || !aib->slsw.v1)
-		return -ENODATA;
-	return sprintf(buf, "%i\n", aib->edf1.u);
-}
-
-static DEVICE_ATTR(untuned, 0400, etr_untuned_show, NULL);
-
-static ssize_t etr_network_id_show(struct device *dev,
-				struct device_attribute *attr, char *buf)
-{
-	struct etr_aib *aib = etr_aib_from_dev(dev);
-
-	if (!aib || !aib->slsw.v1)
-		return -ENODATA;
-	return sprintf(buf, "%i\n", aib->edf1.net_id);
-}
-
-static DEVICE_ATTR(network, 0400, etr_network_id_show, NULL);
-
-static ssize_t etr_id_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	struct etr_aib *aib = etr_aib_from_dev(dev);
-
-	if (!aib || !aib->slsw.v1)
-		return -ENODATA;
-	return sprintf(buf, "%i\n", aib->edf1.etr_id);
-}
-
-static DEVICE_ATTR(id, 0400, etr_id_show, NULL);
-
-static ssize_t etr_port_number_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	struct etr_aib *aib = etr_aib_from_dev(dev);
-
-	if (!aib || !aib->slsw.v1)
-		return -ENODATA;
-	return sprintf(buf, "%i\n", aib->edf1.etr_pn);
-}
-
-static DEVICE_ATTR(port, 0400, etr_port_number_show, NULL);
-
-static ssize_t etr_coupled_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	struct etr_aib *aib = etr_aib_from_dev(dev);
-
-	if (!aib || !aib->slsw.v3)
-		return -ENODATA;
-	return sprintf(buf, "%i\n", aib->edf3.c);
-}
-
-static DEVICE_ATTR(coupled, 0400, etr_coupled_show, NULL);
-
-static ssize_t etr_local_time_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	struct etr_aib *aib = etr_aib_from_dev(dev);
-
-	if (!aib || !aib->slsw.v3)
-		return -ENODATA;
-	return sprintf(buf, "%i\n", aib->edf3.blto);
-}
-
-static DEVICE_ATTR(local_time, 0400, etr_local_time_show, NULL);
-
-static ssize_t etr_utc_offset_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	struct etr_aib *aib = etr_aib_from_dev(dev);
-
-	if (!aib || !aib->slsw.v3)
-		return -ENODATA;
-	return sprintf(buf, "%i\n", aib->edf3.buo);
-}
-
-static DEVICE_ATTR(utc_offset, 0400, etr_utc_offset_show, NULL);
-
-static struct device_attribute *etr_port_attributes[] = {
-	&dev_attr_online,
-	&dev_attr_stepping_control,
-	&dev_attr_state_code,
-	&dev_attr_untuned,
-	&dev_attr_network,
-	&dev_attr_id,
-	&dev_attr_port,
-	&dev_attr_coupled,
-	&dev_attr_local_time,
-	&dev_attr_utc_offset,
-	NULL
-};
-
-static int __init etr_register_port(struct device *dev)
-{
-	struct device_attribute **attr;
-	int rc;
-
-	rc = device_register(dev);
-	if (rc)
-		goto out;
-	for (attr = etr_port_attributes; *attr; attr++) {
-		rc = device_create_file(dev, *attr);
-		if (rc)
-			goto out_unreg;
-	}
-	return 0;
-out_unreg:
-	for (; attr >= etr_port_attributes; attr--)
-		device_remove_file(dev, *attr);
-	device_unregister(dev);
-out:
-	return rc;
-}
-
-static void __init etr_unregister_port(struct device *dev)
-{
-	struct device_attribute **attr;
-
-	for (attr = etr_port_attributes; *attr; attr++)
-		device_remove_file(dev, *attr);
-	device_unregister(dev);
-}
-
-static int __init etr_init_sysfs(void)
-{
-	int rc;
-
-	rc = subsys_system_register(&etr_subsys, NULL);
-	if (rc)
-		goto out;
-	rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_port);
-	if (rc)
-		goto out_unreg_subsys;
-	rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
-	if (rc)
-		goto out_remove_stepping_port;
-	rc = etr_register_port(&etr_port0_dev);
-	if (rc)
-		goto out_remove_stepping_mode;
-	rc = etr_register_port(&etr_port1_dev);
-	if (rc)
-		goto out_remove_port0;
-	return 0;
-
-out_remove_port0:
-	etr_unregister_port(&etr_port0_dev);
-out_remove_stepping_mode:
-	device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
-out_remove_stepping_port:
-	device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_port);
-out_unreg_subsys:
-	bus_unregister(&etr_subsys);
-out:
-	return rc;
-}
-
-device_initcall(etr_init_sysfs);
-
-/*
  * Server Time Protocol (STP) code.
  */
 static bool stp_online;