152 lines
3.5 KiB
C
152 lines
3.5 KiB
C
/*
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* drivers/s390/cio/airq.c
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* Support for adapter interruptions
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*
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* Copyright IBM Corp. 1999,2007
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* Author(s): Ingo Adlung <adlung@de.ibm.com>
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* Cornelia Huck <cornelia.huck@de.ibm.com>
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* Arnd Bergmann <arndb@de.ibm.com>
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* Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/rcupdate.h>
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#include <asm/airq.h>
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#include <asm/isc.h>
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#include "cio.h"
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#include "cio_debug.h"
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#define NR_AIRQS 32
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#define NR_AIRQS_PER_WORD sizeof(unsigned long)
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#define NR_AIRQ_WORDS (NR_AIRQS / NR_AIRQS_PER_WORD)
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union indicator_t {
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unsigned long word[NR_AIRQ_WORDS];
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unsigned char byte[NR_AIRQS];
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} __attribute__((packed));
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struct airq_t {
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adapter_int_handler_t handler;
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void *drv_data;
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};
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static union indicator_t indicators[MAX_ISC+1];
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static struct airq_t *airqs[MAX_ISC+1][NR_AIRQS];
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static int register_airq(struct airq_t *airq, u8 isc)
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{
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int i;
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for (i = 0; i < NR_AIRQS; i++)
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if (!cmpxchg(&airqs[isc][i], NULL, airq))
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return i;
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return -ENOMEM;
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}
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/**
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* s390_register_adapter_interrupt() - register adapter interrupt handler
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* @handler: adapter handler to be registered
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* @drv_data: driver data passed with each call to the handler
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* @isc: isc for which the handler should be called
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*
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* Returns:
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* Pointer to the indicator to be used on success
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* ERR_PTR() if registration failed
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*/
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void *s390_register_adapter_interrupt(adapter_int_handler_t handler,
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void *drv_data, u8 isc)
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{
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struct airq_t *airq;
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char dbf_txt[16];
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int ret;
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if (isc > MAX_ISC)
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return ERR_PTR(-EINVAL);
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airq = kmalloc(sizeof(struct airq_t), GFP_KERNEL);
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if (!airq) {
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ret = -ENOMEM;
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goto out;
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}
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airq->handler = handler;
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airq->drv_data = drv_data;
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ret = register_airq(airq, isc);
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out:
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snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%d", ret);
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CIO_TRACE_EVENT(4, dbf_txt);
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if (ret < 0) {
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kfree(airq);
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return ERR_PTR(ret);
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} else
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return &indicators[isc].byte[ret];
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}
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EXPORT_SYMBOL(s390_register_adapter_interrupt);
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/**
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* s390_unregister_adapter_interrupt - unregister adapter interrupt handler
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* @ind: indicator for which the handler is to be unregistered
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* @isc: interruption subclass
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*/
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void s390_unregister_adapter_interrupt(void *ind, u8 isc)
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{
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struct airq_t *airq;
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char dbf_txt[16];
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int i;
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i = (int) ((addr_t) ind) - ((addr_t) &indicators[isc].byte[0]);
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snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%d", i);
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CIO_TRACE_EVENT(4, dbf_txt);
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indicators[isc].byte[i] = 0;
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airq = xchg(&airqs[isc][i], NULL);
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/*
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* Allow interrupts to complete. This will ensure that the airq handle
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* is no longer referenced by any interrupt handler.
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*/
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synchronize_sched();
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kfree(airq);
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}
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EXPORT_SYMBOL(s390_unregister_adapter_interrupt);
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#define INDICATOR_MASK (0xffUL << ((NR_AIRQS_PER_WORD - 1) * 8))
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void do_adapter_IO(u8 isc)
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{
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int w;
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int i;
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unsigned long word;
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struct airq_t *airq;
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/*
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* Access indicator array in word-sized chunks to minimize storage
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* fetch operations.
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*/
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for (w = 0; w < NR_AIRQ_WORDS; w++) {
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word = indicators[isc].word[w];
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i = w * NR_AIRQS_PER_WORD;
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/*
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* Check bytes within word for active indicators.
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*/
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while (word) {
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if (word & INDICATOR_MASK) {
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airq = airqs[isc][i];
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/* Make sure gcc reads from airqs only once. */
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barrier();
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if (likely(airq))
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airq->handler(&indicators[isc].byte[i],
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airq->drv_data);
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else
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/*
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* Reset ill-behaved indicator.
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*/
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indicators[isc].byte[i] = 0;
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}
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word <<= 8;
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i++;
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}
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}
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}
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