kernel/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/irq.h>
  23
  24 /* Bitmap of IRQ masked */
  25 #define IMASK_PRIORITY  15
  26
  27 static DECLARE_BITMAP(imask_mask, IMASK_PRIORITY);
  28 static int interrupt_priority;
  29
  30 static inline void set_interrupt_registers(int ip)
  31 {
  32         unsigned long __dummy;
  33
  34         asm volatile(
  35 #ifdef CONFIG_CPU_HAS_SR_RB
  36                      "ldc       %2, r6_bank\n\t"
  37 #endif
  38                      "stc       sr, %0\n\t"
  39                      "and       #0xf0, %0\n\t"
  40                      "shlr2     %0\n\t"
  41                      "cmp/eq    #0x3c, %0\n\t"
  42                      "bt/s      1f      ! CLI-ed\n\t"
  43                      " stc      sr, %0\n\t"
  44                      "and       %1, %0\n\t"
  45                      "or        %2, %0\n\t"
  46                      "ldc       %0, sr\n"
  47                      "1:"
  48                      : "=&z" (__dummy)
  49                      : "r" (~0xf0), "r" (ip << 4)
  50                      : "t");
  51 }
  52
  53 static void mask_imask_irq(struct irq_data *data)
  54 {
  55         unsigned int irq = data->irq;
  56
  57         clear_bit(irq, imask_mask);
  58         if (interrupt_priority < IMASK_PRIORITY - irq)
  59                 interrupt_priority = IMASK_PRIORITY - irq;
  60         set_interrupt_registers(interrupt_priority);
  61 }
  62
  63 static void unmask_imask_irq(struct irq_data *data)
  64 {
  65         unsigned int irq = data->irq;
  66
  67         set_bit(irq, imask_mask);
  68         interrupt_priority = IMASK_PRIORITY -
  69                 find_first_zero_bit(imask_mask, IMASK_PRIORITY);
  70         set_interrupt_registers(interrupt_priority);
  71 }
  72
  73 static struct irq_chip imask_irq_chip = {
  74         .name           = "SR.IMASK",
  75         .irq_mask       = mask_imask_irq,
  76         .irq_unmask     = unmask_imask_irq,
  77         .irq_mask_ack   = mask_imask_irq,
  78 };
  79
  80 void make_imask_irq(unsigned int irq)
  81 {
  82         irq_set_chip_and_handler_name(irq, &imask_irq_chip, handle_level_irq,
  83                                       "level");
  84 }