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 #include <asm/pda.h>
  39
  40 static atomic_t irq_err_count;
  41 void ack_bad_irq(unsigned int irq)
  42 {
  43         atomic_inc(&irq_err_count);
  44         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
  45 }
  46
  47 static struct irq_desc bad_irq_desc = {
  48         .handle_irq = handle_bad_irq,
  49         .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
  50 };
  51
  52 #ifdef CONFIG_CPUMASK_OFFSTACK
  53 /* We are not allocating a variable-sized bad_irq_desc.affinity */
  54 #error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
  55 #endif
  56
  57 #ifdef CONFIG_PROC_FS
  58 int show_interrupts(struct seq_file *p, void *v)
  59 {
  60         int i = *(loff_t *) v, j;
  61         struct irqaction *action;
  62         unsigned long flags;
  63
  64         if (i < NR_IRQS) {
  65                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  66                 action = irq_desc[i].action;
  67                 if (!action)
  68                         goto skip;
  69                 seq_printf(p, "%3d: ", i);
  70                 for_each_online_cpu(j)
  71                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
  72                 seq_printf(p, " %8s", irq_desc[i].chip->name);
  73                 seq_printf(p, "  %s", action->name);
  74                 for (action = action->next; action; action = action->next)
  75                         seq_printf(p, "  %s", action->name);
  76
  77                 seq_putc(p, '\n');
  78  skip:
  79                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  80         } else if (i == NR_IRQS) {
  81                 seq_printf(p, "NMI: ");
  82                 for_each_online_cpu(j)
  83                         seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
  84                 seq_printf(p, "     CORE  Non Maskable Interrupt\n");
  85                 seq_printf(p, "Err: %10u\n",  atomic_read(&irq_err_count));
  86         }
  87         return 0;
  88 }
  89 #endif
  90
  91 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  92 static void check_stack_overflow(int irq)
  93 {
  94         /* Debugging check for stack overflow: is there less than STACK_WARN free? */
  95         long sp = __get_SP() & (THREAD_SIZE - 1);
  96
  97         if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
  98                 dump_stack();
  99                 pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
 100                         irq, sp - sizeof(struct thread_info));
 101         }
 102 }
 103 #else
 104 static inline void check_stack_overflow(int irq) { }
 105 #endif
 106
 107 #ifndef CONFIG_IPIPE
 108 static void maybe_lower_to_irq14(void)
 109 {
 110         unsigned short pending, other_ints;
 111
 112         /*
 113          * If we're the only interrupt running (ignoring IRQ15 which
 114          * is for syscalls), lower our priority to IRQ14 so that
 115          * softirqs run at that level.  If there's another,
 116          * lower-level interrupt, irq_exit will defer softirqs to
 117          * that. If the interrupt pipeline is enabled, we are already
 118          * running at IRQ14 priority, so we don't need this code.
 119          */
 120         CSYNC();
 121         pending = bfin_read_IPEND() & ~0x8000;
 122         other_ints = pending & (pending - 1);
 123         if (other_ints == 0)
 124                 lower_to_irq14();
 125 }
 126 #else
 127 static inline void maybe_lower_to_irq14(void) { }
 128 #endif
 129
 130 /*
 131  * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
 132  * come via this function.  Instead, they should provide their
 133  * own 'handler'
 134  */
 135 #ifdef CONFIG_DO_IRQ_L1
 136 __attribute__((l1_text))
 137 #endif
 138 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 139 {
 140         struct pt_regs *old_regs = set_irq_regs(regs);
 141
 142         irq_enter();
 143
 144         check_stack_overflow(irq);
 145
 146         /*
 147          * Some hardware gives randomly wrong interrupts.  Rather
 148          * than crashing, do something sensible.
 149          */
 150         if (irq >= NR_IRQS)
 151                 handle_bad_irq(irq, &bad_irq_desc);
 152         else
 153                 generic_handle_irq(irq);
 154
 155         maybe_lower_to_irq14();
 156
 157         irq_exit();
 158
 159         set_irq_regs(old_regs);
 160 }
 161
 162 void __init init_IRQ(void)
 163 {
 164         init_arch_irq();
 165
 166 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
 167         /* Now that evt_ivhw is set up, turn this on */
 168         trace_buff_offset = 0;
 169         bfin_write_TBUFCTL(BFIN_TRACE_ON);
 170         printk(KERN_INFO "Hardware Trace expanded to %ik\n",
 171           1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
 172 #endif
 173 }