drivers/tty/hvc/hvc_irq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright IBM Corp. 2001,2008
   4  *
   5  * This file contains the IRQ specific code for hvc_console
   6  *
   7  */
   8
   9 #include <linux/interrupt.h>
  10
  11 #include "hvc_console.h"
  12
  13 static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
  14 {
  15         /* if hvc_poll request a repoll, then kick the hvcd thread */
  16         if (hvc_poll(dev_instance))
  17                 hvc_kick();
  18
  19         /*
  20          * We're safe to always return IRQ_HANDLED as the hvcd thread will
  21          * iterate through each hvc_struct.
  22          */
  23         return IRQ_HANDLED;
  24 }
  25
  26 /*
  27  * For IRQ based systems these callbacks can be used
  28  */
  29 int notifier_add_irq(struct hvc_struct *hp, int irq)
  30 {
  31         int rc;
  32
  33         if (!irq) {
  34                 hp->irq_requested = 0;
  35                 return 0;
  36         }
  37         rc = request_irq(irq, hvc_handle_interrupt, hp->flags,
  38                         "hvc_console", hp);
  39         if (!rc)
  40                 hp->irq_requested = 1;
  41         return rc;
  42 }
  43
  44 void notifier_del_irq(struct hvc_struct *hp, int irq)
  45 {
  46         if (!hp->irq_requested)
  47                 return;
  48         free_irq(irq, hp);
  49         hp->irq_requested = 0;
  50 }
  51
  52 void notifier_hangup_irq(struct hvc_struct *hp, int irq)
  53 {
  54         notifier_del_irq(hp, irq);
  55 }