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 atomic_t 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         atomic_inc(&irq_err_count);
  52         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
  53 }
  54
  55 static struct irq_chip bad_chip = {
  56         .ack = dummy_mask_unmask_irq,
  57         .mask = dummy_mask_unmask_irq,
  58         .unmask = dummy_mask_unmask_irq,
  59 };
  60
  61 static struct irq_desc bad_irq_desc = {
  62         .status = IRQ_DISABLED,
  63         .chip = &bad_chip,
  64         .handle_irq = handle_bad_irq,
  65         .depth = 1,
  66         .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
  67 #ifdef CONFIG_SMP
  68         .affinity = CPU_MASK_ALL
  69 #endif
  70 };
  71
  72 #ifdef CONFIG_CPUMASK_OFFSTACK
  73 /* We are not allocating a variable-sized bad_irq_desc.affinity */
  74 #error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
  75 #endif
  76
  77 int show_interrupts(struct seq_file *p, void *v)
  78 {
  79         int i = *(loff_t *) v, j;
  80         struct irqaction *action;
  81         unsigned long flags;
  82
  83         if (i < NR_IRQS) {
  84                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  85                 action = irq_desc[i].action;
  86                 if (!action)
  87                         goto skip;
  88                 seq_printf(p, "%3d: ", i);
  89                 for_each_online_cpu(j)
  90                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  91                 seq_printf(p, " %8s", irq_desc[i].chip->name);
  92                 seq_printf(p, "  %s", action->name);
  93                 for (action = action->next; action; action = action->next)
  94                         seq_printf(p, "  %s", action->name);
  95
  96                 seq_putc(p, '\n');
  97  skip:
  98                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  99         } else if (i == NR_IRQS)
 100                 seq_printf(p, "Err: %10u\n",  atomic_read(&irq_err_count));
 101         return 0;
 102 }
 103
 104 /*
 105  * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
 106  * come via this function.  Instead, they should provide their
 107  * own 'handler'
 108  */
 109 #ifdef CONFIG_DO_IRQ_L1
 110 __attribute__((l1_text))
 111 #endif
 112 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 113 {
 114         struct pt_regs *old_regs;
 115         struct irq_desc *desc = irq_desc + irq;
 116 #ifndef CONFIG_IPIPE
 117         unsigned short pending, other_ints;
 118 #endif
 119         old_regs = set_irq_regs(regs);
 120
 121         /*
 122          * Some hardware gives randomly wrong interrupts.  Rather
 123          * than crashing, do something sensible.
 124          */
 125         if (irq >= NR_IRQS)
 126                 desc = &bad_irq_desc;
 127
 128         irq_enter();
 129 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 130         /* Debugging check for stack overflow: is there less than STACK_WARN free? */
 131         {
 132                 long sp;
 133
 134                 sp = __get_SP() & (THREAD_SIZE-1);
 135
 136                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 137                         dump_stack();
 138                         printk(KERN_EMERG "%s: possible stack overflow while handling irq %i "
 139                                         " only %ld bytes free\n",
 140                                 __func__, irq, sp - sizeof(struct thread_info));
 141                 }
 142         }
 143 #endif
 144         generic_handle_irq(irq);
 145
 146 #ifndef CONFIG_IPIPE    /* Useless and bugous over the I-pipe: IRQs are threaded. */
 147         /* If we're the only interrupt running (ignoring IRQ15 which is for
 148            syscalls), lower our priority to IRQ14 so that softirqs run at
 149            that level.  If there's another, lower-level interrupt, irq_exit
 150            will defer softirqs to that.  */
 151         CSYNC();
 152         pending = bfin_read_IPEND() & ~0x8000;
 153         other_ints = pending & (pending - 1);
 154         if (other_ints == 0)
 155                 lower_to_irq14();
 156 #endif /* !CONFIG_IPIPE */
 157         irq_exit();
 158
 159         set_irq_regs(old_regs);
 160 }
 161
 162 void __init init_IRQ(void)
 163 {
 164         struct irq_desc *desc;
 165         int irq;
 166
 167         spin_lock_init(&irq_controller_lock);
 168         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
 169                 *desc = bad_irq_desc;
 170         }
 171
 172         init_arch_irq();
 173
 174 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
 175         /* Now that evt_ivhw is set up, turn this on */
 176         trace_buff_offset = 0;
 177         bfin_write_TBUFCTL(BFIN_TRACE_ON);
 178         printk(KERN_INFO "Hardware Trace expanded to %ik\n",
 179           1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
 180 #endif
 181 }