#define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
#endif
- -/* xntp 3.4 compatibility names */
+ +/* NTP userland likes the MOD_ prefix better */
#define MOD_OFFSET ADJ_OFFSET
#define MOD_FREQUENCY ADJ_FREQUENCY
#define MOD_MAXERROR ADJ_MAXERROR
#define MOD_ESTERROR ADJ_ESTERROR
#define MOD_STATUS ADJ_STATUS
#define MOD_TIMECONST ADJ_TIMECONST
+ +#define MOD_TAI ADJ_TAI
+ +#define MOD_MICRO ADJ_MICRO
+ +#define MOD_NANO ADJ_NANO
/*
#include <asm/timex.h>
/*
- * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
- * for a slightly underdamped convergence characteristic. SHIFT_KH
- * establishes the damping of the FLL and is chosen by wisdom and black
- * art.
+ * SHIFT_PLL is used as a dampening factor to define how much we
+ * adjust the frequency correction for a given offset in PLL mode.
+ * It also used in dampening the offset correction, to define how
+ * much of the current value in time_offset we correct for each
+ * second. Changing this value changes the stiffness of the ntp
+ * adjustment code. A lower value makes it more flexible, reducing
+ * NTP convergence time. A higher value makes it stiffer, increasing
+ * convergence time, but making the clock more stable.
*
- * MAXTC establishes the maximum time constant of the PLL. With the
- * SHIFT_KG and SHIFT_KF values given and a time constant range from
- * zero to MAXTC, the PLL will converge in 15 minutes to 16 hours,
- * respectively.
+ * In David Mills' nanokernel reference implementation SHIFT_PLL is 4.
+ * However this seems to increase convergence time much too long.
+ *
+ * https://lists.ntp.org/pipermail/hackers/2008-January/003487.html
+ *
+ * In the above mailing list discussion, it seems the value of 4
+ * was appropriate for other Unix systems with HZ=100, and that
+ * SHIFT_PLL should be decreased as HZ increases. However, Linux's
+ * clock steering implementation is HZ independent.
+ *
+ * Through experimentation, a SHIFT_PLL value of 2 was found to allow
+ * for fast convergence (very similar to the NTPv3 code used prior to
+ * v2.6.19), with good clock stability.
+ *
+ *
+ * SHIFT_FLL is used as a dampening factor to define how much we
+ * adjust the frequency correction for a given offset in FLL mode.
+ * In David Mills' nanokernel reference implementation SHIFT_FLL is 2.
+ *
+ * MAXTC establishes the maximum time constant of the PLL.
*/
-#define SHIFT_PLL 4 /* PLL frequency factor (shift) */
+#define SHIFT_PLL 2 /* PLL frequency factor (shift) */
#define SHIFT_FLL 2 /* FLL frequency factor (shift) */
#define MAXTC 10 /* maximum time constant (shift) */
#define SHIFT_USEC 16 /* frequency offset scale (shift) */
#define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
#define PPM_SCALE_INV_SHIFT 19
-#define PPM_SCALE_INV ((1ll << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
+#define PPM_SCALE_INV ((1LL << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
PPM_SCALE + 1)
-#define MAXPHASE 500000000l /* max phase error (ns) */
+#define MAXPHASE 500000000L /* max phase error (ns) */
#define MAXFREQ 500000 /* max frequency error (ns/s) */
#define MAXFREQ_SCALED ((s64)MAXFREQ << NTP_SCALE_SHIFT)
#define MINSEC 256 /* min interval between updates (s) */
#define NTP_SCALE_SHIFT 32
--#ifdef CONFIG_NO_HZ
--#define NTP_INTERVAL_FREQ (2)
--#else
#define NTP_INTERVAL_FREQ (HZ)
--#endif
#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
int read_current_timer(unsigned long *timer_val);
+/* The clock frequency of the i8253/i8254 PIT */
+#define PIT_TICK_RATE 1193182ul
+
#endif /* KERNEL */
#endif /* LINUX_TIMEX_H */
*/
#include <linux/irq.h>
+#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
+#include <linux/sched.h>
#include "internals.h"
-#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
-cpumask_var_t irq_default_affinity;
-
/**
* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
* @irq: interrupt number to wait for
/* Oops, that failed? */
} while (status & IRQ_INPROGRESS);
+
+ /*
+ * We made sure that no hardirq handler is running. Now verify
+ * that no threaded handlers are active.
+ */
+ wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
}
EXPORT_SYMBOL(synchronize_irq);
+#ifdef CONFIG_SMP
+cpumask_var_t irq_default_affinity;
+
/**
* irq_can_set_affinity - Check if the affinity of a given irq can be set
* @irq: Interrupt to check
return 1;
}
+/**
+ * irq_set_thread_affinity - Notify irq threads to adjust affinity
+ * @desc: irq descriptor which has affitnity changed
+ *
+ * We just set IRQTF_AFFINITY and delegate the affinity setting
+ * to the interrupt thread itself. We can not call
+ * set_cpus_allowed_ptr() here as we hold desc->lock and this
+ * code can be called from hard interrupt context.
+ */
+void irq_set_thread_affinity(struct irq_desc *desc)
+{
+ struct irqaction *action = desc->action;
+
+ while (action) {
+ if (action->thread)
+ set_bit(IRQTF_AFFINITY, &action->thread_flags);
+ action = action->next;
+ }
+}
+
/**
* irq_set_affinity - Set the irq affinity of a given irq
* @irq: Interrupt to set affinity
spin_lock_irqsave(&desc->lock, flags);
#ifdef CONFIG_GENERIC_PENDING_IRQ
- if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
- cpumask_copy(desc->affinity, cpumask);
- desc->chip->set_affinity(irq, cpumask);
- } else {
+ if (desc->status & IRQ_MOVE_PCNTXT) {
+ if (!desc->chip->set_affinity(irq, cpumask)) {
+ cpumask_copy(desc->affinity, cpumask);
+ irq_set_thread_affinity(desc);
+ }
+ }
+ else {
desc->status |= IRQ_MOVE_PENDING;
cpumask_copy(desc->pending_mask, cpumask);
}
#else
- cpumask_copy(desc->affinity, cpumask);
- desc->chip->set_affinity(irq, cpumask);
+ if (!desc->chip->set_affinity(irq, cpumask)) {
+ cpumask_copy(desc->affinity, cpumask);
+ irq_set_thread_affinity(desc);
+ }
#endif
desc->status |= IRQ_AFFINITY_SET;
spin_unlock_irqrestore(&desc->lock, flags);
spin_lock_irqsave(&desc->lock, flags);
ret = setup_affinity(irq, desc);
+ if (!ret)
+ irq_set_thread_affinity(desc);
spin_unlock_irqrestore(&desc->lock, flags);
return ret;
if (!desc)
return;
++ chip_bus_lock(irq, desc);
spin_lock_irqsave(&desc->lock, flags);
__disable_irq(desc, irq, false);
spin_unlock_irqrestore(&desc->lock, flags);
++ chip_bus_sync_unlock(irq, desc);
}
EXPORT_SYMBOL(disable_irq_nosync);
* matches the last disable, processing of interrupts on this
* IRQ line is re-enabled.
*
-- * This function may be called from IRQ context.
++ * This function may be called from IRQ context only when
++ * desc->chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
*/
void enable_irq(unsigned int irq)
{
if (!desc)
return;
++ chip_bus_lock(irq, desc);
spin_lock_irqsave(&desc->lock, flags);
__enable_irq(desc, irq, false);
spin_unlock_irqrestore(&desc->lock, flags);
++ chip_bus_sync_unlock(irq, desc);
}
EXPORT_SYMBOL(enable_irq);
return ret;
}
- int wake;
++/*
++ * Default primary interrupt handler for threaded interrupts. Is
++ * assigned as primary handler when request_threaded_irq is called
++ * with handler == NULL. Useful for oneshot interrupts.
++ */
++static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
++{
++ return IRQ_WAKE_THREAD;
++}
++
++/*
++ * Primary handler for nested threaded interrupts. Should never be
++ * called.
++ */
++static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
++{
++ WARN(1, "Primary handler called for nested irq %d\n", irq);
++ return IRQ_NONE;
++}
++
+static int irq_wait_for_interrupt(struct irqaction *action)
+{
+ while (!kthread_should_stop()) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (test_and_clear_bit(IRQTF_RUNTHREAD,
+ &action->thread_flags)) {
+ __set_current_state(TASK_RUNNING);
+ return 0;
+ }
+ schedule();
+ }
+ return -1;
+}
+
++/*
++ * Oneshot interrupts keep the irq line masked until the threaded
++ * handler finished. unmask if the interrupt has not been disabled and
++ * is marked MASKED.
++ */
++static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
++{
++ chip_bus_lock(irq, desc);
++ spin_lock_irq(&desc->lock);
++ if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
++ desc->status &= ~IRQ_MASKED;
++ desc->chip->unmask(irq);
++ }
++ spin_unlock_irq(&desc->lock);
++ chip_bus_sync_unlock(irq, desc);
++}
++
+#ifdef CONFIG_SMP
+/*
+ * Check whether we need to change the affinity of the interrupt thread.
+ */
+static void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
+{
+ cpumask_var_t mask;
+
+ if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
+ return;
+
+ /*
+ * In case we are out of memory we set IRQTF_AFFINITY again and
+ * try again next time
+ */
+ if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
+ set_bit(IRQTF_AFFINITY, &action->thread_flags);
+ return;
+ }
+
+ spin_lock_irq(&desc->lock);
+ cpumask_copy(mask, desc->affinity);
+ spin_unlock_irq(&desc->lock);
+
+ set_cpus_allowed_ptr(current, mask);
+ free_cpumask_var(mask);
+}
+#else
+static inline void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
+#endif
+
+/*
+ * Interrupt handler thread
+ */
+static int irq_thread(void *data)
+{
+ struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
+ struct irqaction *action = data;
+ struct irq_desc *desc = irq_to_desc(action->irq);
++ int wake, oneshot = desc->status & IRQ_ONESHOT;
+
+ sched_setscheduler(current, SCHED_FIFO, ¶m);
+ current->irqaction = action;
+
+ while (!irq_wait_for_interrupt(action)) {
+
+ irq_thread_check_affinity(desc, action);
+
+ atomic_inc(&desc->threads_active);
+
+ spin_lock_irq(&desc->lock);
+ if (unlikely(desc->status & IRQ_DISABLED)) {
+ /*
+ * CHECKME: We might need a dedicated
+ * IRQ_THREAD_PENDING flag here, which
+ * retriggers the thread in check_irq_resend()
+ * but AFAICT IRQ_PENDING should be fine as it
+ * retriggers the interrupt itself --- tglx
+ */
+ desc->status |= IRQ_PENDING;
+ spin_unlock_irq(&desc->lock);
+ } else {
+ spin_unlock_irq(&desc->lock);
+
+ action->thread_fn(action->irq, action->dev_id);
++
++ if (oneshot)
++ irq_finalize_oneshot(action->irq, desc);
+ }
+
+ wake = atomic_dec_and_test(&desc->threads_active);
+
+ if (wake && waitqueue_active(&desc->wait_for_threads))
+ wake_up(&desc->wait_for_threads);
+ }
+
+ /*
+ * Clear irqaction. Otherwise exit_irq_thread() would make
+ * fuzz about an active irq thread going into nirvana.
+ */
+ current->irqaction = NULL;
+ return 0;
+}
+
+/*
+ * Called from do_exit()
+ */
+void exit_irq_thread(void)
+{
+ struct task_struct *tsk = current;
+
+ if (!tsk->irqaction)
+ return;
+
+ printk(KERN_ERR
+ "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+ tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
+
+ /*
+ * Set the THREAD DIED flag to prevent further wakeups of the
+ * soon to be gone threaded handler.
+ */
+ set_bit(IRQTF_DIED, &tsk->irqaction->flags);
+}
+
/*
* Internal function to register an irqaction - typically used to
* allocate special interrupts that are part of the architecture.
struct irqaction *old, **old_ptr;
const char *old_name = NULL;
unsigned long flags;
-- int shared = 0;
++ int nested, shared = 0;
int ret;
if (!desc)
rand_initialize_irq(irq);
}
- * Threaded handler ?
++ /* Oneshot interrupts are not allowed with shared */
++ if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
++ return -EINVAL;
++
++ /*
++ * Check whether the interrupt nests into another interrupt
++ * thread.
++ */
++ nested = desc->status & IRQ_NESTED_THREAD;
++ if (nested) {
++ if (!new->thread_fn)
++ return -EINVAL;
++ /*
++ * Replace the primary handler which was provided from
++ * the driver for non nested interrupt handling by the
++ * dummy function which warns when called.
++ */
++ new->handler = irq_nested_primary_handler;
++ }
++
+ /*
- if (new->thread_fn) {
++ * Create a handler thread when a thread function is supplied
++ * and the interrupt does not nest into another interrupt
++ * thread.
+ */
++ if (new->thread_fn && !nested) {
+ struct task_struct *t;
+
+ t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
+ new->name);
+ if (IS_ERR(t))
+ return PTR_ERR(t);
+ /*
+ * We keep the reference to the task struct even if
+ * the thread dies to avoid that the interrupt code
+ * references an already freed task_struct.
+ */
+ get_task_struct(t);
+ new->thread = t;
+ }
+
/*
* The following block of code has to be executed atomically
*/
if (!shared) {
irq_chip_set_defaults(desc->chip);
+ init_waitqueue_head(&desc->wait_for_threads);
+
/* Setup the type (level, edge polarity) if configured: */
if (new->flags & IRQF_TRIGGER_MASK) {
ret = __irq_set_trigger(desc, irq,
new->flags & IRQF_TRIGGER_MASK);
- if (ret) {
- spin_unlock_irqrestore(&desc->lock, flags);
- return ret;
- }
+ if (ret)
+ goto out_thread;
} else
compat_irq_chip_set_default_handler(desc);
#if defined(CONFIG_IRQ_PER_CPU)
desc->status |= IRQ_PER_CPU;
#endif
-- desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
++ desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
++ if (new->flags & IRQF_ONESHOT)
++ desc->status |= IRQ_ONESHOT;
++
if (!(desc->status & IRQ_NOAUTOEN)) {
desc->depth = 0;
desc->status &= ~IRQ_DISABLED;
(int)(new->flags & IRQF_TRIGGER_MASK));
}
+ new->irq = irq;
*old_ptr = new;
/* Reset broken irq detection when installing new handler */
spin_unlock_irqrestore(&desc->lock, flags);
- new->irq = irq;
+ /*
+ * Strictly no need to wake it up, but hung_task complains
+ * when no hard interrupt wakes the thread up.
+ */
+ if (new->thread)
+ wake_up_process(new->thread);
+
register_irq_proc(irq, desc);
new->dir = NULL;
register_handler_proc(irq, new);
dump_stack();
}
#endif
+ ret = -EBUSY;
+
+out_thread:
spin_unlock_irqrestore(&desc->lock, flags);
- return -EBUSY;
+ if (new->thread) {
+ struct task_struct *t = new->thread;
+
+ new->thread = NULL;
+ if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
+ kthread_stop(t);
+ put_task_struct(t);
+ }
+ return ret;
}
/**
else
desc->chip->disable(irq);
}
+
spin_unlock_irqrestore(&desc->lock, flags);
unregister_handler_proc(irq, action);
local_irq_restore(flags);
}
#endif
+
+ if (action->thread) {
+ if (!test_bit(IRQTF_DIED, &action->thread_flags))
+ kthread_stop(action->thread);
+ put_task_struct(action->thread);
+ }
+
return action;
}
*/
void free_irq(unsigned int irq, void *dev_id)
{
++ struct irq_desc *desc = irq_to_desc(irq);
++
++ if (!desc)
++ return;
++
++ chip_bus_lock(irq, desc);
kfree(__free_irq(irq, dev_id));
++ chip_bus_sync_unlock(irq, desc);
}
EXPORT_SYMBOL(free_irq);
/**
- * request_irq - allocate an interrupt line
+ * request_threaded_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
- * @handler: Function to be called when the IRQ occurs
+ * @handler: Function to be called when the IRQ occurs.
+ * Primary handler for threaded interrupts
++ * If NULL and thread_fn != NULL the default
++ * primary handler is installed
+ * @thread_fn: Function called from the irq handler thread
+ * If NULL, no irq thread is created
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
* raises, you must take care both to initialise your hardware
* and to set up the interrupt handler in the right order.
*
+ * If you want to set up a threaded irq handler for your device
+ * then you need to supply @handler and @thread_fn. @handler ist
+ * still called in hard interrupt context and has to check
+ * whether the interrupt originates from the device. If yes it
+ * needs to disable the interrupt on the device and return
+ * IRQ_WAKE_THREAD which will wake up the handler thread and run
+ * @thread_fn. This split handler design is necessary to support
+ * shared interrupts.
+ *
* Dev_id must be globally unique. Normally the address of the
* device data structure is used as the cookie. Since the handler
* receives this value it makes sense to use it.
* IRQF_TRIGGER_* Specify active edge(s) or level
*
*/
-int request_irq(unsigned int irq, irq_handler_t handler,
- unsigned long irqflags, const char *devname, void *dev_id)
+int request_threaded_irq(unsigned int irq, irq_handler_t handler,
+ irq_handler_t thread_fn, unsigned long irqflags,
+ const char *devname, void *dev_id)
{
struct irqaction *action;
struct irq_desc *desc;
if (desc->status & IRQ_NOREQUEST)
return -EINVAL;
-- if (!handler)
-- return -EINVAL;
++
++ if (!handler) {
++ if (!thread_fn)
++ return -EINVAL;
++ handler = irq_default_primary_handler;
++ }
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;
action->handler = handler;
+ action->thread_fn = thread_fn;
action->flags = irqflags;
action->name = devname;
action->dev_id = dev_id;
++ chip_bus_lock(irq, desc);
retval = __setup_irq(irq, desc, action);
++ chip_bus_sync_unlock(irq, desc);
++
if (retval)
kfree(action);
#ifdef CONFIG_DEBUG_SHIRQ
-- if (irqflags & IRQF_SHARED) {
++ if (!retval && (irqflags & IRQF_SHARED)) {
/*
* It's a shared IRQ -- the driver ought to be prepared for it
* to happen immediately, so let's make sure....
#endif
return retval;
}
-EXPORT_SYMBOL(request_irq);
+EXPORT_SYMBOL(request_threaded_irq);
projects / cascardo / linux.git / commitdiff