arch/blackfin/kernel/irqchip.c

   1 /*
   2  * File:         arch/blackfin/kernel/irqchip.c
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:  This file contains the simple DMA Implementation for Blackfin
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/kernel_stat.h>
  31 #include <linux/module.h>
  32 #include <linux/random.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/kallsyms.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/irq.h>
  37 #include <asm/trace.h>
  38
  39 static unsigned long irq_err_count;
  40 static spinlock_t irq_controller_lock;
  41
  42 /*
  43  * Dummy mask/unmask handler
  44  */
  45 void dummy_mask_unmask_irq(unsigned int irq)
  46 {
  47 }
  48
  49 void ack_bad_irq(unsigned int irq)
  50 {
  51         irq_err_count += 1;
  52         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
  53 }
  54 EXPORT_SYMBOL(ack_bad_irq);
  55
  56 static struct irq_chip bad_chip = {
  57         .ack = dummy_mask_unmask_irq,
  58         .mask = dummy_mask_unmask_irq,
  59         .unmask = dummy_mask_unmask_irq,
  60 };
  61
  62 static struct irq_desc bad_irq_desc = {
  63         .chip = &bad_chip,
  64         .handle_irq = handle_bad_irq,
  65         .depth = 1,
  66 };
  67
  68 int show_interrupts(struct seq_file *p, void *v)
  69 {
  70         int i = *(loff_t *) v;
  71         struct irqaction *action;
  72         unsigned long flags;
  73
  74         if (i < NR_IRQS) {
  75                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  76                 action = irq_desc[i].action;
  77                 if (!action)
  78                         goto unlock;
  79
  80                 seq_printf(p, "%3d: %10u ", i, kstat_irqs(i));
  81                 seq_printf(p, "  %s", action->name);
  82                 for (action = action->next; action; action = action->next)
  83                         seq_printf(p, ", %s", action->name);
  84
  85                 seq_putc(p, '\n');
  86  unlock:
  87                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  88         } else if (i == NR_IRQS) {
  89                 seq_printf(p, "Err: %10lu\n", irq_err_count);
  90         }
  91         return 0;
  92 }
  93
  94 /*
  95  * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
  96  * come via this function.  Instead, they should provide their
  97  * own 'handler'
  98  */
  99
 100 #ifdef CONFIG_DO_IRQ_L1
 101 __attribute__((l1_text))
 102 #endif
 103 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 104 {
 105         struct pt_regs *old_regs;
 106         struct irq_desc *desc = irq_desc + irq;
 107         unsigned short pending, other_ints;
 108
 109         old_regs = set_irq_regs(regs);
 110
 111         /*
 112          * Some hardware gives randomly wrong interrupts.  Rather
 113          * than crashing, do something sensible.
 114          */
 115         if (irq >= NR_IRQS)
 116                 desc = &bad_irq_desc;
 117
 118         irq_enter();
 119
 120         generic_handle_irq(irq);
 121
 122         /* If we're the only interrupt running (ignoring IRQ15 which is for
 123            syscalls), lower our priority to IRQ14 so that softirqs run at
 124            that level.  If there's another, lower-level interrupt, irq_exit
 125            will defer softirqs to that.  */
 126         CSYNC();
 127         pending = bfin_read_IPEND() & ~0x8000;
 128         other_ints = pending & (pending - 1);
 129         if (other_ints == 0)
 130                 lower_to_irq14();
 131         irq_exit();
 132
 133         set_irq_regs(old_regs);
 134 }
 135
 136 void __init init_IRQ(void)
 137 {
 138         struct irq_desc *desc;
 139         int irq;
 140
 141         spin_lock_init(&irq_controller_lock);
 142         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
 143                 *desc = bad_irq_desc;
 144         }
 145
 146         init_arch_irq();
 147
 148 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
 149         /* Now that evt_ivhw is set up, turn this on */
 150         trace_buff_offset = 0;
 151         bfin_write_TBUFCTL(BFIN_TRACE_ON);
 152         printk(KERN_INFO "Hardware Trace expanded to %ik\n",
 153           1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
 154 #endif
 155 }