arch/nios2/kernel/irq.c

   1 /*
   2  * Copyright (C) 2013 Altera Corporation
   3  * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
   4  * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
   5  *
   6  * based on irq.c from m68k which is:
   7  *
   8  * Copyright (C) 2007 Greg Ungerer <gerg@snapgear.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  *
  23  */
  24
  25 #include <linux/init.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/of.h>
  28
  29 static u32 ienable;
  30
  31 asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
  32 {
  33         struct pt_regs *oldregs = set_irq_regs(regs);
  34         int irq;
  35
  36         irq_enter();
  37         irq = irq_find_mapping(NULL, hwirq);
  38         generic_handle_irq(irq);
  39         irq_exit();
  40
  41         set_irq_regs(oldregs);
  42 }
  43
  44 static void chip_unmask(struct irq_data *d)
  45 {
  46         ienable |= (1 << d->hwirq);
  47         WRCTL(CTL_IENABLE, ienable);
  48 }
  49
  50 static void chip_mask(struct irq_data *d)
  51 {
  52         ienable &= ~(1 << d->hwirq);
  53         WRCTL(CTL_IENABLE, ienable);
  54 }
  55
  56 static struct irq_chip m_irq_chip = {
  57         .name           = "NIOS2-INTC",
  58         .irq_unmask     = chip_unmask,
  59         .irq_mask       = chip_mask,
  60 };
  61
  62 static int irq_map(struct irq_domain *h, unsigned int virq,
  63                                 irq_hw_number_t hw_irq_num)
  64 {
  65         irq_set_chip_and_handler(virq, &m_irq_chip, handle_level_irq);
  66
  67         return 0;
  68 }
  69
  70 static const struct irq_domain_ops irq_ops = {
  71         .map    = irq_map,
  72         .xlate  = irq_domain_xlate_onecell,
  73 };
  74
  75 void __init init_IRQ(void)
  76 {
  77         struct irq_domain *domain;
  78         struct device_node *node;
  79
  80         node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.0");
  81         if (!node)
  82                 node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.1");
  83
  84         BUG_ON(!node);
  85
  86         domain = irq_domain_add_linear(node, NIOS2_CPU_NR_IRQS, &irq_ops, NULL);
  87         BUG_ON(!domain);
  88
  89         irq_set_default_host(domain);
  90         of_node_put(node);
  91         /* Load the initial ienable value */
  92         ienable = RDCTL(CTL_IENABLE);
  93 }