MN10300: ASB2364: Handle the IRQ multiplexer in the FPGA

Handle the IRQ multiplexer in the FPGA by implementing a cascade interrupt
driver for it.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 96 insertions, 0 deletions

diff --git a/arch/mn10300/unit-asb2364/irq-fpga.c b/arch/mn10300/unit-asb2364/irq-fpga.c
new file mode 100644
index 000000000000..fcf29754e4d1
--- /dev/null
+++ b/arch/mn10300/unit-asb2364/irq-fpga.c
@@ -0,0 +1,96 @@
+/* ASB2364 FPGA interrupt multiplexing
+ *
+ * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <unit/fpga-regs.h>
+
+/*
+ * FPGA PIC operations
+ */
+static void asb2364_fpga_mask(unsigned int irq)
+{
+	ASB2364_FPGA_REG_MASK(irq - NR_CPU_IRQS) = 0x0001;
+	SyncExBus();
+}
+
+static void asb2364_fpga_ack(unsigned int irq)
+{
+	ASB2364_FPGA_REG_IRQ(irq - NR_CPU_IRQS) = 0x0001;
+	SyncExBus();
+}
+
+static void asb2364_fpga_mask_ack(unsigned int irq)
+{
+	ASB2364_FPGA_REG_MASK(irq - NR_CPU_IRQS) = 0x0001;
+	SyncExBus();
+	ASB2364_FPGA_REG_IRQ(irq - NR_CPU_IRQS) = 0x0001;
+	SyncExBus();
+}
+
+static void asb2364_fpga_unmask(unsigned int irq)
+{
+	ASB2364_FPGA_REG_MASK(irq - NR_CPU_IRQS) = 0x0000;
+	SyncExBus();
+}
+
+static struct irq_chip asb2364_fpga_pic = {
+	.name		= "fpga",
+	.ack		= asb2364_fpga_ack,
+	.mask		= asb2364_fpga_mask,
+	.mask_ack	= asb2364_fpga_mask_ack,
+	.unmask		= asb2364_fpga_unmask,
+};
+
+/*
+ * FPGA PIC interrupt handler
+ */
+static irqreturn_t fpga_interrupt(int irq, void *_mask)
+{
+	if ((ASB2364_FPGA_REG_IRQ_LAN  & 0x0001) != 0x0001)
+		generic_handle_irq(FPGA_LAN_IRQ);
+	if ((ASB2364_FPGA_REG_IRQ_UART & 0x0001) != 0x0001)
+		generic_handle_irq(FPGA_UART_IRQ);
+	if ((ASB2364_FPGA_REG_IRQ_I2C  & 0x0001) != 0x0001)
+		generic_handle_irq(FPGA_I2C_IRQ);
+	if ((ASB2364_FPGA_REG_IRQ_USB  & 0x0001) != 0x0001)
+		generic_handle_irq(FPGA_USB_IRQ);
+	if ((ASB2364_FPGA_REG_IRQ_FPGA & 0x0001) != 0x0001)
+		generic_handle_irq(FPGA_FPGA_IRQ);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Define an interrupt action for each FPGA PIC output
+ */
+static struct irqaction fpga_irq[]  = {
+	[0] = {
+		.handler	= fpga_interrupt,
+		.flags		= IRQF_DISABLED | IRQF_SHARED,
+		.name		= "fpga",
+	},
+};
+
+/*
+ * Initialise the FPGA's PIC
+ */
+void __init irq_fpga_init(void)
+{
+	int irq;
+
+	for (irq = NR_CPU_IRQS; irq < NR_IRQS; irq++)
+		set_irq_chip_and_handler(irq, &asb2364_fpga_pic, handle_level_irq);
+
+	/* the FPGA drives the XIRQ1 input on the CPU PIC */
+	setup_irq(XIRQ1, &fpga_irq[0]);
+}