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/*
* drivers/s390/cio/airq.c
* Support for adapter interruptions
*
* Copyright IBM Corp. 1999,2007
* Author(s): Ingo Adlung <adlung@de.ibm.com>
* Cornelia Huck <cornelia.huck@de.ibm.com>
* Arnd Bergmann <arndb@de.ibm.com>
* Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <asm/airq.h>
#include "cio.h"
#include "cio_debug.h"
#define NR_AIRQS 32
#define NR_AIRQS_PER_WORD sizeof(unsigned long)
#define NR_AIRQ_WORDS (NR_AIRQS / NR_AIRQS_PER_WORD)
union indicator_t {
unsigned long word[NR_AIRQ_WORDS];
unsigned char byte[NR_AIRQS];
} __attribute__((packed));
struct airq_t {
adapter_int_handler_t handler;
void *drv_data;
};
static union indicator_t indicators;
static struct airq_t *airqs[NR_AIRQS];
static int register_airq(struct airq_t *airq)
{
int i;
for (i = 0; i < NR_AIRQS; i++)
if (!cmpxchg(&airqs[i], NULL, airq))
return i;
return -ENOMEM;
}
/**
* s390_register_adapter_interrupt() - register adapter interrupt handler
* @handler: adapter handler to be registered
* @drv_data: driver data passed with each call to the handler
*
* Returns:
* Pointer to the indicator to be used on success
* ERR_PTR() if registration failed
*/
void *s390_register_adapter_interrupt(adapter_int_handler_t handler,
void *drv_data)
{
struct airq_t *airq;
char dbf_txt[16];
int ret;
airq = kmalloc(sizeof(struct airq_t), GFP_KERNEL);
if (!airq) {
ret = -ENOMEM;
goto out;
}
airq->handler = handler;
airq->drv_data = drv_data;
ret = register_airq(airq);
if (ret < 0)
kfree(airq);
out:
snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%d", ret);
CIO_TRACE_EVENT(4, dbf_txt);
if (ret < 0)
return ERR_PTR(ret);
else
return &indicators.byte[ret];
}
EXPORT_SYMBOL(s390_register_adapter_interrupt);
/**
* s390_unregister_adapter_interrupt - unregister adapter interrupt handler
* @ind: indicator for which the handler is to be unregistered
*/
void s390_unregister_adapter_interrupt(void *ind)
{
struct airq_t *airq;
char dbf_txt[16];
int i;
i = (int) ((addr_t) ind) - ((addr_t) &indicators.byte[0]);
snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%d", i);
CIO_TRACE_EVENT(4, dbf_txt);
indicators.byte[i] = 0;
airq = xchg(&airqs[i], NULL);
/*
* Allow interrupts to complete. This will ensure that the airq handle
* is no longer referenced by any interrupt handler.
*/
synchronize_sched();
kfree(airq);
}
EXPORT_SYMBOL(s390_unregister_adapter_interrupt);
#define INDICATOR_MASK (0xffUL << ((NR_AIRQS_PER_WORD - 1) * 8))
void do_adapter_IO(void)
{
int w;
int i;
unsigned long word;
struct airq_t *airq;
/*
* Access indicator array in word-sized chunks to minimize storage
* fetch operations.
*/
for (w = 0; w < NR_AIRQ_WORDS; w++) {
word = indicators.word[w];
i = w * NR_AIRQS_PER_WORD;
/*
* Check bytes within word for active indicators.
*/
while (word) {
if (word & INDICATOR_MASK) {
airq = airqs[i];
if (likely(airq))
airq->handler(&indicators.byte[i],
airq->drv_data);
else
/*
* Reset ill-behaved indicator.
*/
indicators.byte[i] = 0;
}
word <<= 8;
i++;
}
}
}
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