/*
* drivers/s390/cio/airq.c
- * S/390 common I/O routines -- support for adapter interruptions
+ * Support for adapter interruptions
*
- * Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
- * IBM Corporation
- * Author(s): Ingo Adlung (adlung@de.ibm.com)
- * Cornelia Huck (cornelia.huck@de.ibm.com)
- * Arnd Bergmann (arndb@de.ibm.com)
+ * 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/slab.h>
#include <linux/rcupdate.h>
+#include <asm/airq.h>
+
+#include "cio.h"
#include "cio_debug.h"
-#include "airq.h"
-static adapter_int_handler_t adapter_handler;
+#define NR_AIRQS 32
+#define NR_AIRQS_PER_WORD sizeof(unsigned long)
+#define NR_AIRQ_WORDS (NR_AIRQS / NR_AIRQS_PER_WORD)
-/*
- * register for adapter interrupts
- *
- * With HiperSockets the zSeries architecture provides for
- * means of adapter interrups, pseudo I/O interrupts that are
- * not tied to an I/O subchannel, but to an adapter. However,
- * it doesn't disclose the info how to enable/disable them, but
- * to recognize them only. Perhaps we should consider them
- * being shared interrupts, and thus build a linked list
- * of adapter handlers ... to be evaluated ...
- */
-int
-s390_register_adapter_interrupt (adapter_int_handler_t handler)
-{
- int ret;
- char dbf_txt[15];
+union indicator_t {
+ unsigned long word[NR_AIRQ_WORDS];
+ unsigned char byte[NR_AIRQS];
+} __attribute__((packed));
- CIO_TRACE_EVENT (4, "rgaint");
+struct airq_t {
+ adapter_int_handler_t handler;
+ void *drv_data;
+};
- if (handler == NULL)
- ret = -EINVAL;
- else
- ret = (cmpxchg(&adapter_handler, NULL, handler) ? -EBUSY : 0);
- if (!ret)
- synchronize_sched(); /* Allow interrupts to complete. */
+static union indicator_t indicators;
+static struct airq_t *airqs[NR_AIRQS];
- sprintf (dbf_txt, "ret:%d", ret);
- CIO_TRACE_EVENT (4, dbf_txt);
+static int register_airq(struct airq_t *airq)
+{
+ int i;
- return ret;
+ for (i = 0; i < NR_AIRQS; i++)
+ if (!cmpxchg(&airqs[i], NULL, airq))
+ return i;
+ return -ENOMEM;
}
-int
-s390_unregister_adapter_interrupt (adapter_int_handler_t handler)
+/**
+ * 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;
- char dbf_txt[15];
- CIO_TRACE_EVENT (4, "urgaint");
-
- if (handler == NULL)
- ret = -EINVAL;
- else {
- adapter_handler = NULL;
- synchronize_sched(); /* Allow interrupts to complete. */
- ret = 0;
+ airq = kmalloc(sizeof(struct airq_t), GFP_KERNEL);
+ if (!airq) {
+ ret = -ENOMEM;
+ goto out;
}
- sprintf (dbf_txt, "ret:%d", ret);
- CIO_TRACE_EVENT (4, dbf_txt);
-
- return ret;
+ 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);
-void
-do_adapter_IO (void)
+/**
+ * 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)
{
- CIO_TRACE_EVENT (6, "doaio");
+ struct airq_t *airq;
+ char dbf_txt[16];
+ int i;
- if (adapter_handler)
- (*adapter_handler) ();
+ 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))
-EXPORT_SYMBOL (s390_register_adapter_interrupt);
-EXPORT_SYMBOL (s390_unregister_adapter_interrupt);
+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++;
+ }
+ }
+}
projects / linux-flexiantxendom0-3.2.10.git / blobdiff