arch/mn10300/kernel/irq.c

   1 /* MN10300 Arch-specific interrupt handling
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11 #include <linux/module.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/kernel_stat.h>
  14 #include <linux/seq_file.h>
  15 #include <asm/setup.h>
  16
  17 unsigned long __mn10300_irq_enabled_epsw = EPSW_IE | EPSW_IM_7;
  18 EXPORT_SYMBOL(__mn10300_irq_enabled_epsw);
  19
  20 atomic_t irq_err_count;
  21
  22 /*
  23  * MN10300 INTC controller operations
  24  */
  25 static void mn10300_cpupic_disable(unsigned int irq)
  26 {
  27         u16 tmp = GxICR(irq);
  28         GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_DETECT;
  29         tmp = GxICR(irq);
  30 }
  31
  32 static void mn10300_cpupic_enable(unsigned int irq)
  33 {
  34         u16 tmp = GxICR(irq);
  35         GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE;
  36         tmp = GxICR(irq);
  37 }
  38
  39 static void mn10300_cpupic_ack(unsigned int irq)
  40 {
  41         u16 tmp;
  42         *(volatile u8 *) &GxICR(irq) = GxICR_DETECT;
  43         tmp = GxICR(irq);
  44 }
  45
  46 static void mn10300_cpupic_mask(unsigned int irq)
  47 {
  48         u16 tmp = GxICR(irq);
  49         GxICR(irq) = (tmp & GxICR_LEVEL);
  50         tmp = GxICR(irq);
  51 }
  52
  53 static void mn10300_cpupic_mask_ack(unsigned int irq)
  54 {
  55         u16 tmp = GxICR(irq);
  56         GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_DETECT;
  57         tmp = GxICR(irq);
  58 }
  59
  60 static void mn10300_cpupic_unmask(unsigned int irq)
  61 {
  62         u16 tmp = GxICR(irq);
  63         GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT;
  64         tmp = GxICR(irq);
  65 }
  66
  67 static void mn10300_cpupic_end(unsigned int irq)
  68 {
  69         u16 tmp = GxICR(irq);
  70         GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE;
  71         tmp = GxICR(irq);
  72 }
  73
  74 static struct irq_chip mn10300_cpu_pic = {
  75         .name           = "cpu",
  76         .disable        = mn10300_cpupic_disable,
  77         .enable         = mn10300_cpupic_enable,
  78         .ack            = mn10300_cpupic_ack,
  79         .mask           = mn10300_cpupic_mask,
  80         .mask_ack       = mn10300_cpupic_mask_ack,
  81         .unmask         = mn10300_cpupic_unmask,
  82         .end            = mn10300_cpupic_end,
  83 };
  84
  85 /*
  86  * 'what should we do if we get a hw irq event on an illegal vector'.
  87  * each architecture has to answer this themselves.
  88  */
  89 void ack_bad_irq(int irq)
  90 {
  91         printk(KERN_WARNING "unexpected IRQ trap at vector %02x\n", irq);
  92 }
  93
  94 /*
  95  * change the level at which an IRQ executes
  96  * - must not be called whilst interrupts are being processed!
  97  */
  98 void set_intr_level(int irq, u16 level)
  99 {
 100         u16 tmp;
 101
 102         if (in_interrupt())
 103                 BUG();
 104
 105         tmp = GxICR(irq);
 106         GxICR(irq) = (tmp & GxICR_ENABLE) | level;
 107         tmp = GxICR(irq);
 108 }
 109
 110 /*
 111  * mark an interrupt to be ACK'd after interrupt handlers have been run rather
 112  * than before
 113  * - see Documentation/mn10300/features.txt
 114  */
 115 void set_intr_postackable(int irq)
 116 {
 117         set_irq_handler(irq, handle_level_irq);
 118 }
 119
 120 /*
 121  * initialise the interrupt system
 122  */
 123 void __init init_IRQ(void)
 124 {
 125         int irq;
 126
 127         for (irq = 0; irq < NR_IRQS; irq++)
 128                 if (irq_desc[irq].chip == &no_irq_type)
 129                         set_irq_chip_and_handler(irq, &mn10300_cpu_pic,
 130                                                  handle_edge_irq);
 131         unit_init_IRQ();
 132 }
 133
 134 /*
 135  * handle normal device IRQs
 136  */
 137 asmlinkage void do_IRQ(void)
 138 {
 139         unsigned long sp, epsw, irq_disabled_epsw, old_irq_enabled_epsw;
 140         int irq;
 141
 142         sp = current_stack_pointer();
 143         if (sp - (sp & ~(THREAD_SIZE - 1)) < STACK_WARN)
 144                 BUG();
 145
 146         /* make sure local_irq_enable() doesn't muck up the interrupt priority
 147          * setting in EPSW */
 148         old_irq_enabled_epsw = __mn10300_irq_enabled_epsw;
 149         local_save_flags(epsw);
 150         __mn10300_irq_enabled_epsw = EPSW_IE | (EPSW_IM & epsw);
 151         irq_disabled_epsw = EPSW_IE | MN10300_CLI_LEVEL;
 152
 153         __IRQ_STAT(smp_processor_id(), __irq_count)++;
 154
 155         irq_enter();
 156
 157         for (;;) {
 158                 /* ask the interrupt controller for the next IRQ to process
 159                  * - the result we get depends on EPSW.IM
 160                  */
 161                 irq = IAGR & IAGR_GN;
 162                 if (!irq)
 163                         break;
 164
 165                 local_irq_restore(irq_disabled_epsw);
 166
 167                 generic_handle_irq(irq >> 2);
 168
 169                 /* restore IRQ controls for IAGR access */
 170                 local_irq_restore(epsw);
 171         }
 172
 173         __mn10300_irq_enabled_epsw = old_irq_enabled_epsw;
 174
 175         irq_exit();
 176 }
 177
 178 /*
 179  * Display interrupt management information through /proc/interrupts
 180  */
 181 int show_interrupts(struct seq_file *p, void *v)
 182 {
 183         int i = *(loff_t *) v, j, cpu;
 184         struct irqaction *action;
 185         unsigned long flags;
 186
 187         switch (i) {
 188                 /* display column title bar naming CPUs */
 189         case 0:
 190                 seq_printf(p, "           ");
 191                 for (j = 0; j < NR_CPUS; j++)
 192                         if (cpu_online(j))
 193                                 seq_printf(p, "CPU%d       ", j);
 194                 seq_putc(p, '\n');
 195                 break;
 196
 197                 /* display information rows, one per active CPU */
 198         case 1 ... NR_IRQS - 1:
 199                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 200
 201                 action = irq_desc[i].action;
 202                 if (action) {
 203                         seq_printf(p, "%3d: ", i);
 204                         for_each_present_cpu(cpu)
 205                                 seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
 206                         seq_printf(p, " %14s.%u", irq_desc[i].chip->name,
 207                                    (GxICR(i) & GxICR_LEVEL) >>
 208                                    GxICR_LEVEL_SHIFT);
 209                         seq_printf(p, "  %s", action->name);
 210
 211                         for (action = action->next;
 212                              action;
 213                              action = action->next)
 214                                 seq_printf(p, ", %s", action->name);
 215
 216                         seq_putc(p, '\n');
 217                 }
 218
 219                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 220                 break;
 221
 222                 /* polish off with NMI and error counters */
 223         case NR_IRQS:
 224                 seq_printf(p, "NMI: ");
 225                 for (j = 0; j < NR_CPUS; j++)
 226                         if (cpu_online(j))
 227                                 seq_printf(p, "%10u ", nmi_count(j));
 228                 seq_putc(p, '\n');
 229
 230                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 231                 break;
 232         }
 233
 234         return 0;
 235 }