release/src-rt-6.x.4708/linux/linux-2.6.36/arch/alpha/kernel/irq_srm.c

   1 /*
   2  * Handle interrupts from the SRM, assuming no additional weirdness.
   3  */
   4
   5 #include <linux/init.h>
   6 #include <linux/sched.h>
   7 #include <linux/irq.h>
   8
   9 #include "proto.h"
  10 #include "irq_impl.h"
  11
  12
  13 /*
  14  * Is the palcode SMP safe? In other words: can we call cserve_ena/dis
  15  * at the same time in multiple CPUs? To be safe I added a spinlock
  16  * but it can be removed trivially if the palcode is robust against smp.
  17  */
  18 DEFINE_SPINLOCK(srm_irq_lock);
  19
  20 static inline void
  21 srm_enable_irq(unsigned int irq)
  22 {
  23         spin_lock(&srm_irq_lock);
  24         cserve_ena(irq - 16);
  25         spin_unlock(&srm_irq_lock);
  26 }
  27
  28 static void
  29 srm_disable_irq(unsigned int irq)
  30 {
  31         spin_lock(&srm_irq_lock);
  32         cserve_dis(irq - 16);
  33         spin_unlock(&srm_irq_lock);
  34 }
  35
  36 static unsigned int
  37 srm_startup_irq(unsigned int irq)
  38 {
  39         srm_enable_irq(irq);
  40         return 0;
  41 }
  42
  43 static void
  44 srm_end_irq(unsigned int irq)
  45 {
  46         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  47                 srm_enable_irq(irq);
  48 }
  49
  50 /* Handle interrupts from the SRM, assuming no additional weirdness.  */
  51 static struct irq_chip srm_irq_type = {
  52         .name           = "SRM",
  53         .startup        = srm_startup_irq,
  54         .shutdown       = srm_disable_irq,
  55         .enable         = srm_enable_irq,
  56         .disable        = srm_disable_irq,
  57         .ack            = srm_disable_irq,
  58         .end            = srm_end_irq,
  59 };
  60
  61 void __init
  62 init_srm_irqs(long max, unsigned long ignore_mask)
  63 {
  64         long i;
  65
  66         if (NR_IRQS <= 16)
  67                 return;
  68         for (i = 16; i < max; ++i) {
  69                 if (i < 64 && ((ignore_mask >> i) & 1))
  70                         continue;
  71                 irq_desc[i].status = IRQ_DISABLED | IRQ_LEVEL;
  72                 irq_desc[i].chip = &srm_irq_type;
  73         }
  74 }
  75
  76 void
  77 srm_device_interrupt(unsigned long vector)
  78 {
  79         int irq = (vector - 0x800) >> 4;
  80         handle_irq(irq);
  81 }