arch/sh/kernel/cpu/irq/imask.c

   1 /*
   2  * arch/sh/kernel/cpu/irq/imask.c
   3  *
   4  * Copyright (C) 1999, 2000  Niibe Yutaka
   5  *
   6  * Simple interrupt handling using IMASK of SR register.
   7  *
   8  */
   9 /* NOTE: Will not work on level 15 */
  10 #include <linux/ptrace.h>
  11 #include <linux/errno.h>
  12 #include <linux/kernel_stat.h>
  13 #include <linux/signal.h>
  14 #include <linux/sched.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/init.h>
  17 #include <linux/bitops.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/cache.h>
  20 #include <linux/irq.h>
  21 #include <linux/bitmap.h>
  22 #include <asm/system.h>
  23 #include <asm/irq.h>
  24
  25 /* Bitmap of IRQ masked */
  26 #define IMASK_PRIORITY  15
  27
  28 static DECLARE_BITMAP(imask_mask, IMASK_PRIORITY);
  29 static int interrupt_priority;
  30
  31 static inline void set_interrupt_registers(int ip)
  32 {
  33         unsigned long __dummy;
  34
  35         asm volatile(
  36 #ifdef CONFIG_CPU_HAS_SR_RB
  37                      "ldc       %2, r6_bank\n\t"
  38 #endif
  39                      "stc       sr, %0\n\t"
  40                      "and       #0xf0, %0\n\t"
  41                      "shlr2     %0\n\t"
  42                      "cmp/eq    #0x3c, %0\n\t"
  43                      "bt/s      1f      ! CLI-ed\n\t"
  44                      " stc      sr, %0\n\t"
  45                      "and       %1, %0\n\t"
  46                      "or        %2, %0\n\t"
  47                      "ldc       %0, sr\n"
  48                      "1:"
  49                      : "=&z" (__dummy)
  50                      : "r" (~0xf0), "r" (ip << 4)
  51                      : "t");
  52 }
  53
  54 static void mask_imask_irq(unsigned int irq)
  55 {
  56         clear_bit(irq, imask_mask);
  57         if (interrupt_priority < IMASK_PRIORITY - irq)
  58                 interrupt_priority = IMASK_PRIORITY - irq;
  59         set_interrupt_registers(interrupt_priority);
  60 }
  61
  62 static void unmask_imask_irq(unsigned int irq)
  63 {
  64         set_bit(irq, imask_mask);
  65         interrupt_priority = IMASK_PRIORITY -
  66                 find_first_zero_bit(imask_mask, IMASK_PRIORITY);
  67         set_interrupt_registers(interrupt_priority);
  68 }
  69
  70 static struct irq_chip imask_irq_chip = {
  71         .typename       = "SR.IMASK",
  72         .mask           = mask_imask_irq,
  73         .unmask         = unmask_imask_irq,
  74         .mask_ack       = mask_imask_irq,
  75 };
  76
  77 void make_imask_irq(unsigned int irq)
  78 {
  79         set_irq_chip_and_handler_name(irq, &imask_irq_chip,
  80                                       handle_level_irq, "level");
  81 }