nios2: Interrupt handling

This patch adds the support for IRQ handling.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 93 insertions, 0 deletions

diff --git a/arch/nios2/kernel/irq.c b/arch/nios2/kernel/irq.c
new file mode 100644
index 0000000..f5b74ae
--- /dev/null
+++ b/arch/nios2/kernel/irq.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * based on irq.c from m68k which is:
+ *
+ * Copyright (C) 2007 Greg Ungerer <gerg@snapgear.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+
+static u32 ienable;
+
+asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
+{
+	struct pt_regs *oldregs = set_irq_regs(regs);
+	int irq;
+
+	irq_enter();
+	irq = irq_find_mapping(NULL, hwirq);
+	generic_handle_irq(irq);
+	irq_exit();
+
+	set_irq_regs(oldregs);
+}
+
+static void chip_unmask(struct irq_data *d)
+{
+	ienable |= (1 << d->hwirq);
+	WRCTL(CTL_IENABLE, ienable);
+}
+
+static void chip_mask(struct irq_data *d)
+{
+	ienable &= ~(1 << d->hwirq);
+	WRCTL(CTL_IENABLE, ienable);
+}
+
+static struct irq_chip m_irq_chip = {
+	.name		= "NIOS2-INTC",
+	.irq_unmask	= chip_unmask,
+	.irq_mask	= chip_mask,
+};
+
+static int irq_map(struct irq_domain *h, unsigned int virq,
+				irq_hw_number_t hw_irq_num)
+{
+	irq_set_chip_and_handler(virq, &m_irq_chip, handle_level_irq);
+
+	return 0;
+}
+
+static struct irq_domain_ops irq_ops = {
+	.map	= irq_map,
+	.xlate	= irq_domain_xlate_onecell,
+};
+
+void __init init_IRQ(void)
+{
+	struct irq_domain *domain;
+	struct device_node *node;
+
+	node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.0");
+	if (!node)
+		node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.1");
+
+	BUG_ON(!node);
+
+	domain = irq_domain_add_linear(node, NIOS2_CPU_NR_IRQS, &irq_ops, NULL);
+	BUG_ON(!domain);
+
+	irq_set_default_host(domain);
+	of_node_put(node);
+	/* Load the initial ienable value */
+	ienable = RDCTL(CTL_IENABLE);
+}