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 static spinlock_t irq_controller_lock;
  42
  43 /*
  44  * Dummy mask/unmask handler
  45  */
  46 void dummy_mask_unmask_irq(unsigned int irq)
  47 {
  48 }
  49
  50 void ack_bad_irq(unsigned int irq)
  51 {
  52         atomic_inc(&irq_err_count);
  53         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
  54 }
  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 #ifdef CONFIG_CPUMASK_OFFSTACK
  74 /* We are not allocating a variable-sized bad_irq_desc.affinity */
  75 #error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
  76 #endif
  77
  78 int show_interrupts(struct seq_file *p, void *v)
  79 {
  80         int i = *(loff_t *) v, j;
  81         struct irqaction *action;
  82         unsigned long flags;
  83
  84         if (i < NR_IRQS) {
  85                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  86                 action = irq_desc[i].action;
  87                 if (!action)
  88                         goto skip;
  89                 seq_printf(p, "%3d: ", i);
  90                 for_each_online_cpu(j)
  91                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  92                 seq_printf(p, " %8s", irq_desc[i].chip->name);
  93                 seq_printf(p, "  %s", action->name);
  94                 for (action = action->next; action; action = action->next)
  95                         seq_printf(p, "  %s", action->name);
  96
  97                 seq_putc(p, '\n');
  98  skip:
  99                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 100         } else if (i == NR_IRQS) {
 101                 seq_printf(p, "NMI: ");
 102                 for_each_online_cpu(j)
 103                         seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
 104                 seq_printf(p, "     CORE  Non Maskable Interrupt\n");
 105                 seq_printf(p, "Err: %10u\n",  atomic_read(&irq_err_count));
 106         }
 107         return 0;
 108 }
 109
 110 /*
 111  * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
 112  * come via this function.  Instead, they should provide their
 113  * own 'handler'
 114  */
 115 #ifdef CONFIG_DO_IRQ_L1
 116 __attribute__((l1_text))
 117 #endif
 118 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 119 {
 120         struct pt_regs *old_regs;
 121         struct irq_desc *desc = irq_desc + irq;
 122 #ifndef CONFIG_IPIPE
 123         unsigned short pending, other_ints;
 124 #endif
 125         old_regs = set_irq_regs(regs);
 126
 127         /*
 128          * Some hardware gives randomly wrong interrupts.  Rather
 129          * than crashing, do something sensible.
 130          */
 131         if (irq >= NR_IRQS)
 132                 desc = &bad_irq_desc;
 133
 134         irq_enter();
 135 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 136         /* Debugging check for stack overflow: is there less than STACK_WARN free? */
 137         {
 138                 long sp;
 139
 140                 sp = __get_SP() & (THREAD_SIZE-1);
 141
 142                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 143                         dump_stack();
 144                         printk(KERN_EMERG "%s: possible stack overflow while handling irq %i "
 145                                         " only %ld bytes free\n",
 146                                 __func__, irq, sp - sizeof(struct thread_info));
 147                 }
 148         }
 149 #endif
 150         generic_handle_irq(irq);
 151
 152 #ifndef CONFIG_IPIPE    /* Useless and bugous over the I-pipe: IRQs are threaded. */
 153         /* If we're the only interrupt running (ignoring IRQ15 which is for
 154            syscalls), lower our priority to IRQ14 so that softirqs run at
 155            that level.  If there's another, lower-level interrupt, irq_exit
 156            will defer softirqs to that.  */
 157         CSYNC();
 158         pending = bfin_read_IPEND() & ~0x8000;
 159         other_ints = pending & (pending - 1);
 160         if (other_ints == 0)
 161                 lower_to_irq14();
 162 #endif /* !CONFIG_IPIPE */
 163         irq_exit();
 164
 165         set_irq_regs(old_regs);
 166 }
 167
 168 void __init init_IRQ(void)
 169 {
 170         struct irq_desc *desc;
 171         int irq;
 172
 173         spin_lock_init(&irq_controller_lock);
 174         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
 175                 *desc = bad_irq_desc;
 176         }
 177
 178         init_arch_irq();
 179
 180 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
 181         /* Now that evt_ivhw is set up, turn this on */
 182         trace_buff_offset = 0;
 183         bfin_write_TBUFCTL(BFIN_TRACE_ON);
 184         printk(KERN_INFO "Hardware Trace expanded to %ik\n",
 185           1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
 186 #endif
 187 }