arch/c6x/kernel/irq.c

   1 /*
   2  *  Copyright (C) 2011-2012 Texas Instruments Incorporated
   3  *
   4  *  This borrows heavily from powerpc version, which is:
   5  *
   6  *  Derived from arch/i386/kernel/irq.c
   7  *    Copyright (C) 1992 Linus Torvalds
   8  *  Adapted from arch/i386 by Gary Thomas
   9  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  10  *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
  11  *    Copyright (C) 1996-2001 Cort Dougan
  12  *  Adapted for Power Macintosh by Paul Mackerras
  13  *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version
  18  * 2 of the License, or (at your option) any later version.
  19  */
  20 #include <linux/slab.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/radix-tree.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/of_irq.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/kernel_stat.h>
  28
  29 #include <asm/megamod-pic.h>
  30 #include <asm/special_insns.h>
  31
  32 unsigned long irq_err_count;
  33
  34 static DEFINE_RAW_SPINLOCK(core_irq_lock);
  35
  36 static void mask_core_irq(struct irq_data *data)
  37 {
  38         unsigned int prio = data->hwirq;
  39
  40         raw_spin_lock(&core_irq_lock);
  41         and_creg(IER, ~(1 << prio));
  42         raw_spin_unlock(&core_irq_lock);
  43 }
  44
  45 static void unmask_core_irq(struct irq_data *data)
  46 {
  47         unsigned int prio = data->hwirq;
  48
  49         raw_spin_lock(&core_irq_lock);
  50         or_creg(IER, 1 << prio);
  51         raw_spin_unlock(&core_irq_lock);
  52 }
  53
  54 static struct irq_chip core_chip = {
  55         .name           = "core",
  56         .irq_mask       = mask_core_irq,
  57         .irq_unmask     = unmask_core_irq,
  58 };
  59
  60 static int prio_to_virq[NR_PRIORITY_IRQS];
  61
  62 asmlinkage void c6x_do_IRQ(unsigned int prio, struct pt_regs *regs)
  63 {
  64         struct pt_regs *old_regs = set_irq_regs(regs);
  65
  66         irq_enter();
  67
  68         generic_handle_irq(prio_to_virq[prio]);
  69
  70         irq_exit();
  71
  72         set_irq_regs(old_regs);
  73 }
  74
  75 static struct irq_domain *core_domain;
  76
  77 static int core_domain_map(struct irq_domain *h, unsigned int virq,
  78                            irq_hw_number_t hw)
  79 {
  80         if (hw < 4 || hw >= NR_PRIORITY_IRQS)
  81                 return -EINVAL;
  82
  83         prio_to_virq[hw] = virq;
  84
  85         irq_set_status_flags(virq, IRQ_LEVEL);
  86         irq_set_chip_and_handler(virq, &core_chip, handle_level_irq);
  87         return 0;
  88 }
  89
  90 static const struct irq_domain_ops core_domain_ops = {
  91         .map = core_domain_map,
  92         .xlate = irq_domain_xlate_onecell,
  93 };
  94
  95 void __init init_IRQ(void)
  96 {
  97         struct device_node *np;
  98
  99         /* Mask all priority IRQs */
 100         and_creg(IER, ~0xfff0);
 101
 102         np = of_find_compatible_node(NULL, NULL, "ti,c64x+core-pic");
 103         if (np != NULL) {
 104                 /* create the core host */
 105                 core_domain = irq_domain_add_linear(np, NR_PRIORITY_IRQS,
 106                                                     &core_domain_ops, NULL);
 107                 if (core_domain)
 108                         irq_set_default_host(core_domain);
 109                 of_node_put(np);
 110         }
 111
 112         printk(KERN_INFO "Core interrupt controller initialized\n");
 113
 114         /* now we're ready for other SoC controllers */
 115         megamod_pic_init();
 116
 117         /* Clear all general IRQ flags */
 118         set_creg(ICR, 0xfff0);
 119 }
 120
 121 void ack_bad_irq(int irq)
 122 {
 123         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
 124         irq_err_count++;
 125 }
 126
 127 int arch_show_interrupts(struct seq_file *p, int prec)
 128 {
 129         seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
 130         return 0;
 131 }