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linux_old1/arch/s390/kernel/time.c

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/*
* arch/s390/kernel/time.c
* Time of day based timer functions.
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Hartmut Penner (hp@de.ibm.com),
* Martin Schwidefsky (schwidefsky@de.ibm.com),
* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
*
* Derived from "arch/i386/kernel/time.c"
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/types.h>
#include <linux/profile.h>
#include <linux/timex.h>
#include <linux/notifier.h>
#include <linux/clocksource.h>
#include <asm/uaccess.h>
#include <asm/delay.h>
#include <asm/s390_ext.h>
#include <asm/div64.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/timer.h>
#include <asm/etr.h>
/* change this if you have some constant time drift */
#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
/* The value of the TOD clock for 1.1.1970. */
#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
/*
* Create a small time difference between the timer interrupts
* on the different cpus to avoid lock contention.
*/
#define CPU_DEVIATION (smp_processor_id() << 12)
#define TICK_SIZE tick
static ext_int_info_t ext_int_info_cc;
static ext_int_info_t ext_int_etr_cc;
static u64 init_timer_cc;
static u64 jiffies_timer_cc;
static u64 xtime_cc;
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
return ((get_clock() - jiffies_timer_cc) * 125) >> 9;
}
/*
* Monotonic_clock - returns # of nanoseconds passed since time_init()
*/
unsigned long long monotonic_clock(void)
{
return sched_clock();
}
EXPORT_SYMBOL(monotonic_clock);
void tod_to_timeval(__u64 todval, struct timespec *xtime)
{
unsigned long long sec;
sec = todval >> 12;
do_div(sec, 1000000);
xtime->tv_sec = sec;
todval -= (sec * 1000000) << 12;
xtime->tv_nsec = ((todval * 1000) >> 12);
}
#ifdef CONFIG_PROFILING
#define s390_do_profile() profile_tick(CPU_PROFILING)
#else
#define s390_do_profile() do { ; } while(0)
#endif /* CONFIG_PROFILING */
/*
* Advance the per cpu tick counter up to the time given with the
* "time" argument. The per cpu update consists of accounting
* the virtual cpu time, calling update_process_times and calling
* the profiling hook. If xtime is before time it is advanced as well.
*/
void account_ticks(u64 time)
{
__u32 ticks;
__u64 tmp;
/* Calculate how many ticks have passed. */
if (time < S390_lowcore.jiffy_timer)
return;
tmp = time - S390_lowcore.jiffy_timer;
if (tmp >= 2*CLK_TICKS_PER_JIFFY) { /* more than two ticks ? */
ticks = __div(tmp, CLK_TICKS_PER_JIFFY) + 1;
S390_lowcore.jiffy_timer +=
CLK_TICKS_PER_JIFFY * (__u64) ticks;
} else if (tmp >= CLK_TICKS_PER_JIFFY) {
ticks = 2;
S390_lowcore.jiffy_timer += 2*CLK_TICKS_PER_JIFFY;
} else {
ticks = 1;
S390_lowcore.jiffy_timer += CLK_TICKS_PER_JIFFY;
}
#ifdef CONFIG_SMP
/*
* Do not rely on the boot cpu to do the calls to do_timer.
* Spread it over all cpus instead.
*/
write_seqlock(&xtime_lock);
if (S390_lowcore.jiffy_timer > xtime_cc) {
__u32 xticks;
tmp = S390_lowcore.jiffy_timer - xtime_cc;
if (tmp >= 2*CLK_TICKS_PER_JIFFY) {
xticks = __div(tmp, CLK_TICKS_PER_JIFFY);
xtime_cc += (__u64) xticks * CLK_TICKS_PER_JIFFY;
} else {
xticks = 1;
xtime_cc += CLK_TICKS_PER_JIFFY;
}
do_timer(xticks);
}
write_sequnlock(&xtime_lock);
#else
do_timer(ticks);
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
account_tick_vtime(current);
#else
while (ticks--)
update_process_times(user_mode(get_irq_regs()));
#endif
s390_do_profile();
}
#ifdef CONFIG_NO_IDLE_HZ
#ifdef CONFIG_NO_IDLE_HZ_INIT
int sysctl_hz_timer = 0;
#else
int sysctl_hz_timer = 1;
#endif
/*
* Stop the HZ tick on the current CPU.
* Only cpu_idle may call this function.
*/
static void stop_hz_timer(void)
{
unsigned long flags;
unsigned long seq, next;
__u64 timer, todval;
int cpu = smp_processor_id();
if (sysctl_hz_timer != 0)
return;
cpu_set(cpu, nohz_cpu_mask);
/*
* Leave the clock comparator set up for the next timer
* tick if either rcu or a softirq is pending.
*/
if (rcu_needs_cpu(cpu) || local_softirq_pending()) {
cpu_clear(cpu, nohz_cpu_mask);
return;
}
/*
* This cpu is going really idle. Set up the clock comparator
* for the next event.
*/
next = next_timer_interrupt();
do {
seq = read_seqbegin_irqsave(&xtime_lock, flags);
timer = ((__u64) next) - ((__u64) jiffies) + jiffies_64;
} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
todval = -1ULL;
/* Be careful about overflows. */
if (timer < (-1ULL / CLK_TICKS_PER_JIFFY)) {
timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY;
if (timer >= jiffies_timer_cc)
todval = timer;
}
set_clock_comparator(todval);
}
/*
* Start the HZ tick on the current CPU.
* Only cpu_idle may call this function.
*/
static void start_hz_timer(void)
{
BUG_ON(!in_interrupt());
if (!cpu_isset(smp_processor_id(), nohz_cpu_mask))
return;
account_ticks(get_clock());
set_clock_comparator(S390_lowcore.jiffy_timer + CPU_DEVIATION);
cpu_clear(smp_processor_id(), nohz_cpu_mask);
}
static int nohz_idle_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
switch (action) {
case CPU_IDLE:
stop_hz_timer();
break;
case CPU_NOT_IDLE:
start_hz_timer();
break;
}
return NOTIFY_OK;
}
static struct notifier_block nohz_idle_nb = {
.notifier_call = nohz_idle_notify,
};
static void __init nohz_init(void)
{
if (register_idle_notifier(&nohz_idle_nb))
panic("Couldn't register idle notifier");
}
#endif
/*
* Set up per cpu jiffy timer and set the clock comparator.
*/
static void setup_jiffy_timer(void)
{
/* Set up clock comparator to next jiffy. */
S390_lowcore.jiffy_timer =
jiffies_timer_cc + (jiffies_64 + 1) * CLK_TICKS_PER_JIFFY;
set_clock_comparator(S390_lowcore.jiffy_timer + CPU_DEVIATION);
}
/*
* Set up lowcore and control register of the current cpu to
* enable TOD clock and clock comparator interrupts.
*/
void init_cpu_timer(void)
{
setup_jiffy_timer();
/* Enable clock comparator timer interrupt. */
__ctl_set_bit(0,11);
/* Always allow ETR external interrupts, even without an ETR. */
__ctl_set_bit(0, 4);
}
static void clock_comparator_interrupt(__u16 code)
{
/* set clock comparator for next tick */
set_clock_comparator(S390_lowcore.jiffy_timer + CPU_DEVIATION);
}
static void etr_reset(void);
static void etr_init(void);
static void etr_ext_handler(__u16);
/*
* Get the TOD clock running.
*/
static u64 __init reset_tod_clock(void)
{
u64 time;
etr_reset();
if (store_clock(&time) == 0)
return time;
/* TOD clock not running. Set the clock to Unix Epoch. */
if (set_clock(TOD_UNIX_EPOCH) != 0 || store_clock(&time) != 0)
panic("TOD clock not operational.");
return TOD_UNIX_EPOCH;
}
static cycle_t read_tod_clock(void)
{
return get_clock();
}
static struct clocksource clocksource_tod = {
.name = "tod",
.rating = 100,
.read = read_tod_clock,
.mask = -1ULL,
.mult = 1000,
.shift = 12,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* Initialize the TOD clock and the CPU timer of
* the boot cpu.
*/
void __init time_init(void)
{
init_timer_cc = reset_tod_clock();
xtime_cc = init_timer_cc + CLK_TICKS_PER_JIFFY;
jiffies_timer_cc = init_timer_cc - jiffies_64 * CLK_TICKS_PER_JIFFY;
/* set xtime */
tod_to_timeval(init_timer_cc - TOD_UNIX_EPOCH, &xtime);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
/* request the clock comparator external interrupt */
if (register_early_external_interrupt(0x1004,
clock_comparator_interrupt,
&ext_int_info_cc) != 0)
panic("Couldn't request external interrupt 0x1004");
if (clocksource_register(&clocksource_tod) != 0)
panic("Could not register TOD clock source");
/* request the etr external interrupt */
if (register_early_external_interrupt(0x1406, etr_ext_handler,
&ext_int_etr_cc) != 0)
panic("Couldn't request external interrupt 0x1406");
/* Enable TOD clock interrupts on the boot cpu. */
init_cpu_timer();
#ifdef CONFIG_NO_IDLE_HZ
nohz_init();
#endif
#ifdef CONFIG_VIRT_TIMER
vtime_init();
#endif
etr_init();
}
/*
* External Time Reference (ETR) code.
*/
static int etr_port0_online;
static int etr_port1_online;
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,
};
enum etr_flags {
ETR_FLAG_ENOSYS,
ETR_FLAG_EACCES,
ETR_FLAG_STEAI,
};
/*
* 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 unsigned long etr_flags;
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 struct tasklet_struct etr_tasklet;
static DEFINE_PER_CPU(atomic_t, etr_sync_word);
static void etr_timeout(unsigned long dummy);
static void etr_tasklet_fn(unsigned long dummy);
/*
* The etr get_clock function. It will write the current clock value
* to the clock pointer and return 0 if the clock is in sync with the
* external time source. If the clock mode is local it will return
* -ENOSYS and -EAGAIN if the clock is not in sync with the external
* reference. This function is what ETR is all about..
*/
int get_sync_clock(unsigned long long *clock)
{
atomic_t *sw_ptr;
unsigned int sw0, sw1;
sw_ptr = &get_cpu_var(etr_sync_word);
sw0 = atomic_read(sw_ptr);
*clock = get_clock();
sw1 = atomic_read(sw_ptr);
put_cpu_var(etr_sync_sync);
if (sw0 == sw1 && (sw0 & 0x80000000U))
/* Success: time is in sync. */
return 0;
if (test_bit(ETR_FLAG_ENOSYS, &etr_flags))
return -ENOSYS;
if (test_bit(ETR_FLAG_EACCES, &etr_flags))
return -EACCES;
return -EAGAIN;
}
EXPORT_SYMBOL(get_sync_clock);
/*
* Make get_sync_clock return -EAGAIN.
*/
static void etr_disable_sync_clock(void *dummy)
{
atomic_t *sw_ptr = &__get_cpu_var(etr_sync_word);
/*
* Clear the in-sync bit 2^31. All get_sync_clock calls will
* fail until the sync bit is turned back on. In addition
* increase the "sequence" counter to avoid the race of an
* etr event and the complete recovery against get_sync_clock.
*/
atomic_clear_mask(0x80000000, sw_ptr);
atomic_inc(sw_ptr);
}
/*
* Make get_sync_clock return 0 again.
* Needs to be called from a context disabled for preemption.
*/
static void etr_enable_sync_clock(void)
{
atomic_t *sw_ptr = &__get_cpu_var(etr_sync_word);
atomic_set_mask(0x80000000, sw_ptr);
}
/*
* 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_clock();
else {
set_bit(ETR_FLAG_ENOSYS, &etr_flags);
if (etr_port0_online || etr_port1_online) {
printk(KERN_WARNING "Running on non ETR capable "
"machine, only local mode available.\n");
etr_port0_online = etr_port1_online = 0;
}
}
}
static void etr_init(void)
{
struct etr_aib aib;
if (test_bit(ETR_FLAG_ENOSYS, &etr_flags))
return;
/* Check if this machine has the steai instruction. */
if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
set_bit(ETR_FLAG_STEAI, &etr_flags);
setup_timer(&etr_timer, etr_timeout, 0UL);
tasklet_init(&etr_tasklet, etr_tasklet_fn, 0);
if (!etr_port0_online && !etr_port1_online)
set_bit(ETR_FLAG_EACCES, &etr_flags);
if (etr_port0_online) {
set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
tasklet_hi_schedule(&etr_tasklet);
}
if (etr_port1_online) {
set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
tasklet_hi_schedule(&etr_tasklet);
}
}
/*
* 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.
*/
void etr_switch_to_local(void)
{
if (!etr_eacr.sl)
return;
etr_disable_sync_clock(NULL);
set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events);
tasklet_hi_schedule(&etr_tasklet);
}
/*
* 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.
*/
void etr_sync_check(void)
{
if (!etr_eacr.es)
return;
etr_disable_sync_clock(NULL);
set_bit(ETR_EVENT_SYNC_CHECK, &etr_events);
tasklet_hi_schedule(&etr_tasklet);
}
/*
* ETR external interrupt. 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_ext_handler(__u16 code)
{
struct etr_interruption_parameter *intparm =
(struct etr_interruption_parameter *) &S390_lowcore.ext_params;
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);
tasklet_hi_schedule(&etr_tasklet);
}
static void etr_timeout(unsigned long dummy)
{
set_bit(ETR_EVENT_UPDATE, &etr_events);
tasklet_hi_schedule(&etr_tasklet);
}
/*
* 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;
}
/*
* The time is "clock". xtime is what we think the time is.
* Adjust the value by a multiple of jiffies and add the delta to ntp.
* "delay" is an approximation how long the synchronization took. If
* the time correction is positive, then "delay" is subtracted from
* the time difference and only the remaining part is passed to ntp.
*/
static void etr_adjust_time(unsigned long long clock, unsigned long long delay)
{
unsigned long long delta, ticks;
struct timex adjust;
/*
* We don't have to take the xtime lock because the cpu
* executing etr_adjust_time is running disabled in
* tasklet context and all other cpus are looping in
* etr_sync_cpu_start.
*/
if (clock > xtime_cc) {
/* It is later than we thought. */
delta = ticks = clock - xtime_cc;
delta = ticks = (delta < delay) ? 0 : delta - delay;
delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
init_timer_cc = init_timer_cc + delta;
jiffies_timer_cc = jiffies_timer_cc + delta;
xtime_cc = xtime_cc + delta;
adjust.offset = ticks * (1000000 / HZ);
} else {
/* It is earlier than we thought. */
delta = ticks = xtime_cc - clock;
delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
init_timer_cc = init_timer_cc - delta;
jiffies_timer_cc = jiffies_timer_cc - delta;
xtime_cc = xtime_cc - delta;
adjust.offset = -ticks * (1000000 / HZ);
}
if (adjust.offset != 0) {
printk(KERN_NOTICE "etr: time adjusted by %li micro-seconds\n",
adjust.offset);
adjust.modes = ADJ_OFFSET_SINGLESHOT;
do_adjtimex(&adjust);
}
}
#ifdef CONFIG_SMP
static void etr_sync_cpu_start(void *dummy)
{
int *in_sync = dummy;
etr_enable_sync_clock();
/*
* This looks like a busy wait loop but it isn't. etr_sync_cpus
* is called on all other cpus while the TOD clocks is stopped.
* __udelay will stop the cpu on an enabled wait psw until the
* TOD is running again.
*/
while (*in_sync == 0) {
__udelay(1);
/*
* A different cpu changes *in_sync. Therefore use
* barrier() to force memory access.
*/
barrier();
}
if (*in_sync != 1)
/* Didn't work. Clear per-cpu in sync bit again. */
etr_disable_sync_clock(NULL);
/*
* This round of TOD syncing is done. Set the clock comparator
* to the next tick and let the processor continue.
*/
setup_jiffy_timer();
}
static void etr_sync_cpu_end(void *dummy)
{
}
#endif /* CONFIG_SMP */
/*
* Sync the TOD clock using the port refered 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(struct etr_aib *aib, int port)
{
struct etr_aib *sync_port;
unsigned long long clock, delay;
int in_sync, 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;
/*
* Catch all other cpus and make them wait until we have
* successfully synced the clock. smp_call_function will
* return after all other cpus are in etr_sync_cpu_start.
*/
in_sync = 0;
preempt_disable();
smp_call_function(etr_sync_cpu_start,&in_sync,0,0);
local_irq_disable();
etr_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;
if (set_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;
etr_adjust_time(clock, delay);
setup_jiffy_timer();
/* Verify that the clock is properly set. */
if (!etr_aib_follows(sync_port, aib, port)) {
/* Didn't work. */
etr_disable_sync_clock(NULL);
in_sync = -EAGAIN;
rc = -EAGAIN;
} else {
in_sync = 1;
rc = 0;
}
} else {
/* Could not set the clock ?!? */
__ctl_clear_bit(0, 29);
__ctl_clear_bit(14, 21);
etr_disable_sync_clock(NULL);
in_sync = -EAGAIN;
rc = -EAGAIN;
}
local_irq_enable();
smp_call_function(etr_sync_cpu_end,NULL,0,0);
preempt_enable();
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_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_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_tasklet_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)
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 (test_bit(ETR_FLAG_STEAI, &etr_flags)) {
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_clock();
}
/*
* ETR tasklet. 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_tasklet_fn(unsigned long dummy)
{
unsigned long long now;
struct etr_eacr eacr;
struct etr_aib aib;
int sync_port;
/* 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(etr_disable_sync_clock, NULL, 0, 1);
del_timer_sync(&etr_timer);
etr_update_eacr(eacr);
set_bit(ETR_FLAG_EACCES, &etr_flags);
return;
}
/* 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_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 prefered 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;
clear_bit(ETR_FLAG_EACCES, &etr_flags);
} 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;
clear_bit(ETR_FLAG_EACCES, &etr_flags);
} 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;
clear_bit(ETR_FLAG_EACCES, &etr_flags);
} 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;
clear_bit(ETR_FLAG_EACCES, &etr_flags);
} else {
/* Both ports not usable. */
eacr.es = eacr.sl = 0;
sync_port = -1;
set_bit(ETR_FLAG_EACCES, &etr_flags);
}
/*
* 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 || sync_port < 0) {
etr_update_eacr(eacr);
etr_set_tolec_timeout(now);
return;
}
/*
* 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 occured) 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(&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);
}
/*
* Sysfs interface functions
*/
static struct sysdev_class etr_sysclass = {
set_kset_name("etr")
};
static struct sys_device etr_port0_dev = {
.id = 0,
.cls = &etr_sysclass,
};
static struct sys_device etr_port1_dev = {
.id = 1,
.cls = &etr_sysclass,
};
/*
* ETR class attributes
*/
static ssize_t etr_stepping_port_show(struct sysdev_class *class, char *buf)
{
return sprintf(buf, "%i\n", etr_port0.esw.p);
}
static SYSDEV_CLASS_ATTR(stepping_port, 0400, etr_stepping_port_show, NULL);
static ssize_t etr_stepping_mode_show(struct sysdev_class *class, 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 SYSDEV_CLASS_ATTR(stepping_mode, 0400, etr_stepping_mode_show, NULL);
/*
* ETR port attributes
*/
static inline struct etr_aib *etr_aib_from_dev(struct sys_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 sys_device *dev, 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 sys_device *dev,
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(ETR_FLAG_ENOSYS, &etr_flags))
return -ENOSYS;
if (dev == &etr_port0_dev) {
if (etr_port0_online == value)
return count; /* Nothing to do. */
etr_port0_online = value;
set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
tasklet_hi_schedule(&etr_tasklet);
} else {
if (etr_port1_online == value)
return count; /* Nothing to do. */
etr_port1_online = value;
set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
tasklet_hi_schedule(&etr_tasklet);
}
return count;
}
static SYSDEV_ATTR(online, 0600, etr_online_show, etr_online_store);
static ssize_t etr_stepping_control_show(struct sys_device *dev, char *buf)
{
return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
etr_eacr.e0 : etr_eacr.e1);
}
static SYSDEV_ATTR(stepping_control, 0400, etr_stepping_control_show, NULL);
static ssize_t etr_mode_code_show(struct sys_device *dev, 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 SYSDEV_ATTR(state_code, 0400, etr_mode_code_show, NULL);
static ssize_t etr_untuned_show(struct sys_device *dev, 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 SYSDEV_ATTR(untuned, 0400, etr_untuned_show, NULL);
static ssize_t etr_network_id_show(struct sys_device *dev, 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 SYSDEV_ATTR(network, 0400, etr_network_id_show, NULL);
static ssize_t etr_id_show(struct sys_device *dev, 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 SYSDEV_ATTR(id, 0400, etr_id_show, NULL);
static ssize_t etr_port_number_show(struct sys_device *dev, 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 SYSDEV_ATTR(port, 0400, etr_port_number_show, NULL);
static ssize_t etr_coupled_show(struct sys_device *dev, 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 SYSDEV_ATTR(coupled, 0400, etr_coupled_show, NULL);
static ssize_t etr_local_time_show(struct sys_device *dev, 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 SYSDEV_ATTR(local_time, 0400, etr_local_time_show, NULL);
static ssize_t etr_utc_offset_show(struct sys_device *dev, 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 SYSDEV_ATTR(utc_offset, 0400, etr_utc_offset_show, NULL);
static struct sysdev_attribute *etr_port_attributes[] = {
&attr_online,
&attr_stepping_control,
&attr_state_code,
&attr_untuned,
&attr_network,
&attr_id,
&attr_port,
&attr_coupled,
&attr_local_time,
&attr_utc_offset,
NULL
};
static int __init etr_register_port(struct sys_device *dev)
{
struct sysdev_attribute **attr;
int rc;
rc = sysdev_register(dev);
if (rc)
goto out;
for (attr = etr_port_attributes; *attr; attr++) {
rc = sysdev_create_file(dev, *attr);
if (rc)
goto out_unreg;
}
return 0;
out_unreg:
for (; attr >= etr_port_attributes; attr--)
sysdev_remove_file(dev, *attr);
sysdev_unregister(dev);
out:
return rc;
}
static void __init etr_unregister_port(struct sys_device *dev)
{
struct sysdev_attribute **attr;
for (attr = etr_port_attributes; *attr; attr++)
sysdev_remove_file(dev, *attr);
sysdev_unregister(dev);
}
static int __init etr_init_sysfs(void)
{
int rc;
rc = sysdev_class_register(&etr_sysclass);
if (rc)
goto out;
rc = sysdev_class_create_file(&etr_sysclass, &attr_stepping_port);
if (rc)
goto out_unreg_class;
rc = sysdev_class_create_file(&etr_sysclass, &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:
sysdev_class_remove_file(&etr_sysclass, &attr_stepping_mode);
out_remove_stepping_port:
sysdev_class_remove_file(&etr_sysclass, &attr_stepping_port);
out_unreg_class:
sysdev_class_unregister(&etr_sysclass);
out:
return rc;
}
device_initcall(etr_init_sysfs);
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