[S390] cio: Extend adapter interrupt interface.

From: Cornelia Huck <cornelia.huck@de.ibm.com>

Change the adapter interrupt interface in order to allow multiple
adapter interrupt handlers to be registered. Indicators are now
allocated by cio instead of the device driver.

The qdio parts have been
Acked-by: Ursula Braun <ubraun@linux.vnet.ibm.com>

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 115 insertions, 56 deletions

diff --git a/drivers/s390/cio/airq.c b/drivers/s390/cio/airq.c
index 5287631fbfc..b7a07a86629 100644
--- a/drivers/s390/cio/airq.c
+++ b/drivers/s390/cio/airq.c
@@ -1,12 +1,12 @@
 /*
  *  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>
@@ -14,72 +14,131 @@
 #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++;
+		}
+	}
+}