drivers/s390/cio/airq.c

   1 /*
   2  *    Support for adapter interruptions
   3  *
   4  *    Copyright IBM Corp. 1999, 2007
   5  *    Author(s): Ingo Adlung <adlung@de.ibm.com>
   6  *               Cornelia Huck <cornelia.huck@de.ibm.com>
   7  *               Arnd Bergmann <arndb@de.ibm.com>
   8  *               Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/irq.h>
  13 #include <linux/kernel_stat.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/rculist.h>
  17 #include <linux/slab.h>
  18
  19 #include <asm/airq.h>
  20 #include <asm/isc.h>
  21
  22 #include "cio.h"
  23 #include "cio_debug.h"
  24 #include "ioasm.h"
  25
  26 static DEFINE_SPINLOCK(airq_lists_lock);
  27 static struct hlist_head airq_lists[MAX_ISC+1];
  28
  29 /**
  30  * register_adapter_interrupt() - register adapter interrupt handler
  31  * @airq: pointer to adapter interrupt descriptor
  32  *
  33  * Returns 0 on success, or -EINVAL.
  34  */
  35 int register_adapter_interrupt(struct airq_struct *airq)
  36 {
  37         char dbf_txt[32];
  38
  39         if (!airq->handler || airq->isc > MAX_ISC)
  40                 return -EINVAL;
  41         if (!airq->lsi_ptr) {
  42                 airq->lsi_ptr = kzalloc(1, GFP_KERNEL);
  43                 if (!airq->lsi_ptr)
  44                         return -ENOMEM;
  45                 airq->flags |= AIRQ_PTR_ALLOCATED;
  46         }
  47         if (!airq->lsi_mask)
  48                 airq->lsi_mask = 0xff;
  49         snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%p", airq);
  50         CIO_TRACE_EVENT(4, dbf_txt);
  51         isc_register(airq->isc);
  52         spin_lock(&airq_lists_lock);
  53         hlist_add_head_rcu(&airq->list, &airq_lists[airq->isc]);
  54         spin_unlock(&airq_lists_lock);
  55         return 0;
  56 }
  57 EXPORT_SYMBOL(register_adapter_interrupt);
  58
  59 /**
  60  * unregister_adapter_interrupt - unregister adapter interrupt handler
  61  * @airq: pointer to adapter interrupt descriptor
  62  */
  63 void unregister_adapter_interrupt(struct airq_struct *airq)
  64 {
  65         char dbf_txt[32];
  66
  67         if (hlist_unhashed(&airq->list))
  68                 return;
  69         snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%p", airq);
  70         CIO_TRACE_EVENT(4, dbf_txt);
  71         spin_lock(&airq_lists_lock);
  72         hlist_del_rcu(&airq->list);
  73         spin_unlock(&airq_lists_lock);
  74         synchronize_rcu();
  75         isc_unregister(airq->isc);
  76         if (airq->flags & AIRQ_PTR_ALLOCATED) {
  77                 kfree(airq->lsi_ptr);
  78                 airq->lsi_ptr = NULL;
  79                 airq->flags &= ~AIRQ_PTR_ALLOCATED;
  80         }
  81 }
  82 EXPORT_SYMBOL(unregister_adapter_interrupt);
  83
  84 void do_adapter_IO(u8 isc)
  85 {
  86         struct airq_struct *airq;
  87         struct hlist_head *head;
  88
  89         head = &airq_lists[isc];
  90         rcu_read_lock();
  91         hlist_for_each_entry_rcu(airq, head, list)
  92                 if ((*airq->lsi_ptr & airq->lsi_mask) != 0)
  93                         airq->handler(airq);
  94         rcu_read_unlock();
  95 }