blob: 604fbdf1dd159d014579ae51ff5d85dfc6a0575f [file] [log] [blame]
/*
* arch/s390/kernel/irq.c
*
* S390 version
* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Ingo Adlung (adlung@de.ibm.com)
*
* Derived from "arch/i386/kernel/irq.c"
* Copyright (C) 1992, 1999 Linus Torvalds, Ingo Molnar
*
* S/390 I/O interrupt processing and I/O request processing is
* implemented in arch/s390/kernel/s390io.c
*/
#include <linux/module.h>
#include <linux/config.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/threads.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/bitops.h>
#include <asm/smp.h>
#include <asm/pgtable.h>
#include <asm/delay.h>
#include <asm/lowcore.h>
void s390_init_IRQ ( void );
void s390_free_irq ( unsigned int irq, void *dev_id);
int s390_request_irq( unsigned int irq,
void (*handler)(int, void *, struct pt_regs *),
unsigned long irqflags,
const char *devname,
void *dev_id);
#if 0
/*
* The following vectors are part of the Linux architecture, there
* is no hardware IRQ pin equivalent for them, they are triggered
* through the ICC by us (IPIs), via smp_message_pass():
*/
BUILD_SMP_INTERRUPT(reschedule_interrupt)
BUILD_SMP_INTERRUPT(invalidate_interrupt)
BUILD_SMP_INTERRUPT(stop_cpu_interrupt)
BUILD_SMP_INTERRUPT(mtrr_interrupt)
BUILD_SMP_INTERRUPT(spurious_interrupt)
#endif
/*
* Global interrupt locks for SMP. Allow interrupts to come in on any
* CPU, yet make cli/sti act globally to protect critical regions..
*/
#ifdef CONFIG_SMP
atomic_t global_irq_holder = ATOMIC_INIT(NO_PROC_ID);
atomic_t global_irq_lock = ATOMIC_INIT(0);
atomic_t global_irq_count = ATOMIC_INIT(0);
atomic_t global_bh_count;
/*
* "global_cli()" is a special case, in that it can hold the
* interrupts disabled for a longish time, and also because
* we may be doing TLB invalidates when holding the global
* IRQ lock for historical reasons. Thus we may need to check
* SMP invalidate events specially by hand here (but not in
* any normal spinlocks)
*
* Thankfully we don't need this as we can deliver flush tlbs with
* interrupts disabled DJB :-)
*/
#define check_smp_invalidate(cpu)
static void show(char * str)
{
int i;
unsigned long *stack;
int cpu = smp_processor_id();
printk("\n%s, CPU %d:\n", str, cpu);
printk("irq: %d [%d]\n",
atomic_read(&global_irq_count),local_irq_count(smp_processor_id()));
printk("bh: %d [%d]\n",
atomic_read(&global_bh_count),local_bh_count(smp_processor_id()));
stack = (unsigned long *) &str;
for (i = 40; i ; i--) {
unsigned long x = *++stack;
if (x > (unsigned long) &init_task_union && x < (unsigned long) &vsprintf) {
printk("<[%08lx]> ", x);
}
}
}
#define MAXCOUNT 100000000
static inline void wait_on_bh(void)
{
int count = MAXCOUNT;
do {
if (!--count) {
show("wait_on_bh");
count = ~0;
}
/* nothing .. wait for the other bh's to go away */
} while (atomic_read(&global_bh_count) != 0);
}
static inline void wait_on_irq(int cpu)
{
int count = MAXCOUNT;
for (;;) {
/*
* Wait until all interrupts are gone. Wait
* for bottom half handlers unless we're
* already executing in one..
*/
if (!atomic_read(&global_irq_count)) {
if (local_bh_count(cpu)||
!atomic_read(&global_bh_count))
break;
}
/* Duh, we have to loop. Release the lock to avoid deadlocks */
atomic_set(&global_irq_lock, 0);
for (;;) {
if (!--count) {
show("wait_on_irq");
count = ~0;
}
__sti();
SYNC_OTHER_CORES(cpu);
__cli();
check_smp_invalidate(cpu);
if (atomic_read(&global_irq_count))
continue;
if (atomic_read(&global_irq_lock))
continue;
if (!local_bh_count(cpu)
&& atomic_read(&global_bh_count))
continue;
if (!atomic_compare_and_swap(0, 1, &global_irq_lock))
break;
}
}
}
/*
* This is called when we want to synchronize with
* bottom half handlers. We need to wait until
* no other CPU is executing any bottom half handler.
*
* Don't wait if we're already running in an interrupt
* context or are inside a bh handler.
*/
void synchronize_bh(void)
{
if (atomic_read(&global_bh_count) && !in_interrupt())
wait_on_bh();
}
/*
* This is called when we want to synchronize with
* interrupts. We may for example tell a device to
* stop sending interrupts: but to make sure there
* are no interrupts that are executing on another
* CPU we need to call this function.
*/
void synchronize_irq(void)
{
if (atomic_read(&global_irq_count)) {
/* Stupid approach */
cli();
sti();
}
}
static inline void get_irqlock(int cpu)
{
if (atomic_compare_and_swap(0, 1, &global_irq_lock) != 0) {
/* do we already hold the lock? */
if ( cpu == atomic_read(&global_irq_holder))
return;
/* Uhhuh.. Somebody else got it. Wait.. */
do {
check_smp_invalidate(cpu);
} while (atomic_compare_and_swap(0, 1, &global_irq_lock) != 0);
}
/*
* We also to make sure that nobody else is running
* in an interrupt context.
*/
wait_on_irq(cpu);
/*
* Ok, finally..
*/
atomic_set(&global_irq_holder,cpu);
}
#define EFLAGS_I_SHIFT 25
/*
* A global "cli()" while in an interrupt context
* turns into just a local cli(). Interrupts
* should use spinlocks for the (very unlikely)
* case that they ever want to protect against
* each other.
*
* If we already have local interrupts disabled,
* this will not turn a local disable into a
* global one (problems with spinlocks: this makes
* save_flags+cli+sti usable inside a spinlock).
*/
void __global_cli(void)
{
unsigned long flags;
__save_flags(flags);
if (flags & (1 << EFLAGS_I_SHIFT)) {
int cpu = smp_processor_id();
__cli();
if (!in_irq())
get_irqlock(cpu);
}
}
void __global_sti(void)
{
if (!in_irq())
release_irqlock(smp_processor_id());
__sti();
}
/*
* SMP flags value to restore to:
* 0 - global cli
* 1 - global sti
* 2 - local cli
* 3 - local sti
*/
unsigned long __global_save_flags(void)
{
int retval;
int local_enabled;
unsigned long flags;
__save_flags(flags);
local_enabled = (flags >> EFLAGS_I_SHIFT) & 1;
/* default to local */
retval = 2 + local_enabled;
/* check for global flags if we're not in an interrupt */
if (!in_irq())
{
if (local_enabled)
retval = 1;
if (atomic_read(&global_irq_holder)== smp_processor_id())
retval = 0;
}
return retval;
}
void __global_restore_flags(unsigned long flags)
{
switch (flags) {
case 0:
__global_cli();
break;
case 1:
__global_sti();
break;
case 2:
__cli();
break;
case 3:
__sti();
break;
default:
printk("global_restore_flags: %08lx (%08lx)\n",
flags, (&flags)[-1]);
}
}
#endif
void __init init_IRQ(void)
{
s390_init_IRQ();
}
void free_irq(unsigned int irq, void *dev_id)
{
s390_free_irq( irq, dev_id);
}
int request_irq( unsigned int irq,
void (*handler)(int, void *, struct pt_regs *),
unsigned long irqflags,
const char *devname,
void *dev_id)
{
return( s390_request_irq( irq, handler, irqflags, devname, dev_id ) );
}
void init_irq_proc(void)
{
/* For now, nothing... */
}
#ifdef CONFIG_SMP
EXPORT_SYMBOL(__global_cli);
EXPORT_SYMBOL(__global_sti);
EXPORT_SYMBOL(__global_save_flags);
EXPORT_SYMBOL(__global_restore_flags);
EXPORT_SYMBOL(global_irq_holder);
EXPORT_SYMBOL(global_irq_lock);
EXPORT_SYMBOL(global_irq_count);
EXPORT_SYMBOL(global_bh_count);
#endif
EXPORT_SYMBOL(global_bh_lock);