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         .status = IRQ_DISABLED,
  64         .chip = &bad_chip,
  65         .handle_irq = handle_bad_irq,
  66         .depth = 1,
  67         .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
  68 #ifdef CONFIG_SMP
  69         .affinity = CPU_MASK_ALL
  70 #endif
  71 };
  72
  73 int show_interrupts(struct seq_file *p, void *v)
  74 {
  75         int i = *(loff_t *) v;
  76         struct irqaction *action;
  77         unsigned long flags;
  78
  79         if (i < NR_IRQS) {
  80                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  81                 action = irq_desc[i].action;
  82                 if (!action)
  83                         goto unlock;
  84
  85                 seq_printf(p, "%3d: %10u ", i, kstat_irqs(i));
  86                 seq_printf(p, "  %s", action->name);
  87                 for (action = action->next; action; action = action->next)
  88                         seq_printf(p, ", %s", action->name);
  89
  90                 seq_putc(p, '\n');
  91  unlock:
  92                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  93         } else if (i == NR_IRQS) {
  94                 seq_printf(p, "Err: %10lu\n", irq_err_count);
  95         }
  96         return 0;
  97 }
  98
  99 /*
 100  * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
 101  * come via this function.  Instead, they should provide their
 102  * own 'handler'
 103  */
 104
 105 #ifdef CONFIG_DO_IRQ_L1
 106 __attribute__((l1_text))
 107 #endif
 108 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 109 {
 110         struct pt_regs *old_regs;
 111         struct irq_desc *desc = irq_desc + irq;
 112         unsigned short pending, other_ints;
 113
 114         old_regs = set_irq_regs(regs);
 115
 116         /*
 117          * Some hardware gives randomly wrong interrupts.  Rather
 118          * than crashing, do something sensible.
 119          */
 120         if (irq >= NR_IRQS)
 121                 desc = &bad_irq_desc;
 122
 123         irq_enter();
 124
 125         generic_handle_irq(irq);
 126
 127         /* If we're the only interrupt running (ignoring IRQ15 which is for
 128            syscalls), lower our priority to IRQ14 so that softirqs run at
 129            that level.  If there's another, lower-level interrupt, irq_exit
 130            will defer softirqs to that.  */
 131         CSYNC();
 132         pending = bfin_read_IPEND() & ~0x8000;
 133         other_ints = pending & (pending - 1);
 134         if (other_ints == 0)
 135                 lower_to_irq14();
 136         irq_exit();
 137
 138         set_irq_regs(old_regs);
 139 }
 140
 141 void __init init_IRQ(void)
 142 {
 143         struct irq_desc *desc;
 144         int irq;
 145
 146         spin_lock_init(&irq_controller_lock);
 147         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
 148                 *desc = bad_irq_desc;
 149         }
 150
 151         init_arch_irq();
 152
 153 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
 154         /* Now that evt_ivhw is set up, turn this on */
 155         trace_buff_offset = 0;
 156         bfin_write_TBUFCTL(BFIN_TRACE_ON);
 157         printk(KERN_INFO "Hardware Trace expanded to %ik\n",
 158           1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
 159 #endif
 160 }