kernel/core/irq.cc

   1 // core/irq.cc -- generic IRQ handling
   2 //
   3 // This software is copyright (c) 2006 Scott Wood <scott@buserror.net>.
   4 //
   5 // This software is provided 'as-is', without any express or implied warranty.
   6 // In no event will the authors or contributors be held liable for any damages
   7 // arising from the use of this software.
   8 //
   9 // Permission is hereby granted to everyone, free of charge, to use, copy,
  10 // modify, prepare derivative works of, publish, distribute, perform,
  11 // sublicense, and/or sell copies of the Software, provided that the above
  12 // copyright notice and disclaimer of warranty be included in all copies or
  13 // substantial portions of this software.
  14
  15
  16 #include <kern/kernel.h>
  17 #include <kern/irq.h>
  18
  19 namespace IRQ {
  20         void InterruptController::request_int(InterruptSlot *slot, Interrupt *irq)
  21         {
  22                 AutoSpinLockIRQ autolock(lock);
  23
  24                 u32 irqnum = get_irqnum(slot);
  25                 Interrupt *list = slot->first_int;
  26                 Interrupt **insert = &slot->first_int;
  27
  28                 while (list) {
  29                         if (list == irq)
  30                                 throw_idl(ResourceBusy, -1, countarray("IRQ in use"));
  31
  32                         insert = &list->next;
  33                         list = *insert;
  34                 }
  35
  36                 *insert = irq;
  37                 irq->slot = slot;
  38                 irq->controller = this;
  39
  40                 if (insert == &slot->first_int && slot->mask_count == 0) {
  41                         // There were no existing handlers, so it's currently masked
  42                         unmask(irqnum);
  43                 }
  44         }
  45
  46         void InterruptController::free_int(Interrupt *irq)
  47         {
  48                 InterruptSlot *slot = irq->slot;
  49                 u32 irqnum = get_irqnum(slot);
  50
  51                 DroppableAutoSpinLockIRQ autolock(lock);
  52
  53                 Interrupt *list = slot->first_int;
  54                 Interrupt **remove = &slot->first_int;
  55
  56                 while (list) {
  57                         if (list == irq) {
  58                                 *remove = list->next;
  59
  60                                 if (remove == &slot->first_int && !list->next &&
  61                                     slot->mask_count == 0)
  62                                 {
  63                                         // It was the last handler for this IRQ num.
  64                                         mask(irqnum);
  65                                 }
  66
  67                                 autolock.unlock();
  68                                 wait_for_irq(slot);
  69                                 return;
  70                         }
  71
  72                         remove = &list->next;
  73                         list = *remove;
  74                 }
  75
  76                 throw_idl(InvalidReference, 0, nullarray);
  77         }
  78
  79         bool InterruptController::handle_irq(int irq)
  80         {
  81                 DroppableAutoSpinLock autolock(lock);
  82                 bool handled_one = false;
  83                 bool irq_specified = irq >= 0;
  84
  85                 in_irq = true;
  86
  87                 do {
  88                         if (!irq_specified) {
  89                                 irq = get_pending_irq();
  90
  91                                 if (irq < 0)
  92                                         break;
  93                         }
  94
  95                         mask_and_ack(irq);
  96
  97                         InterruptSlot *slot = get_slot(irq);
  98
  99                         if (slot->mask_count > 0 || slot->flags & InterruptSlot::Running) {
 100                                 slot->flags |= InterruptSlot::Pending;
 101                                 continue;
 102                         }
 103
 104                         slot->flags |= InterruptSlot::Running;
 105                         assert(!(slot->flags & InterruptSlot::Pending));
 106
 107                         autolock.unlock();
 108
 109                         for (Interrupt *i = slot->first_int; i; i = i->next)
 110                                 handled_one |= i->action();
 111
 112                         autolock.lock();
 113
 114                         slot->flags &= ~InterruptSlot::Running;
 115
 116                         if (slot->mask_count == 0)
 117                                 unmask(irq);
 118                 } while (!irq_specified);
 119
 120                 in_irq = false;
 121                 return handled_one;
 122         }
 123
 124         void InterruptController::rec_mask_nowait(InterruptSlot *slot)
 125         {
 126                 AutoSpinLockIRQ autolock(lock);
 127                 u32 irq = get_irqnum(slot);
 128
 129                 if (slot->mask_count++ == 0)
 130                         mask(irq);
 131         }
 132
 133         void InterruptController::rec_mask(InterruptSlot *slot)
 134         {
 135                 rec_mask_nowait(slot);
 136                 wait_for_irq(slot);
 137         }
 138
 139         void InterruptController::rec_unmask(InterruptSlot *slot)
 140         {
 141                 bool was_pending = false;
 142                 DroppableAutoSpinLockRecIRQ autolock(lock);
 143
 144                 if (--slot->mask_count == 0) {
 145                         unmask(get_irqnum(slot));
 146
 147                         if (slot->flags & InterruptSlot::Pending) {
 148                                 was_pending = true;
 149                                 slot->flags &= ~InterruptSlot::Pending;
 150                                 slot->flags |= InterruptSlot::Running;
 151                         }
 152                 }
 153
 154                 autolock.unlock();
 155
 156                 if (was_pending) {
 157                         // Only really necessary for edge-triggered interrupts
 158
 159                         for (Interrupt *i = slot->first_int; i; i = i->next)
 160                                 i->action();
 161
 162                         autolock.lock();
 163                         slot->flags &= ~InterruptSlot::Running;
 164                         autolock.unlock();
 165                 }
 166         }
 167
 168         void InterruptController::wait_for_irq(InterruptSlot *slot)
 169         {
 170                 while (slot->flags & InterruptSlot::Running)
 171                         ll_busywait();
 172         }
 173
 174         bool in_irq;
 175 }
 176
 177 //#include "irq-server/footer.cc"