1/* ASB2364 FPGA interrupt multiplexing
2 *
3 * Copyright (C) 2010 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
12#include <linux/interrupt.h>
13#include <linux/init.h>
14#include <linux/irq.h>
15#include <unit/fpga-regs.h>
16
17/*
18 * FPGA PIC operations
19 */
20static void asb2364_fpga_mask(struct irq_data *d)
21{
22	ASB2364_FPGA_REG_MASK(d->irq - NR_CPU_IRQS) = 0x0001;
23	SyncExBus();
24}
25
26static void asb2364_fpga_ack(struct irq_data *d)
27{
28	ASB2364_FPGA_REG_IRQ(d->irq - NR_CPU_IRQS) = 0x0001;
29	SyncExBus();
30}
31
32static void asb2364_fpga_mask_ack(struct irq_data *d)
33{
34	ASB2364_FPGA_REG_MASK(d->irq - NR_CPU_IRQS) = 0x0001;
35	SyncExBus();
36	ASB2364_FPGA_REG_IRQ(d->irq - NR_CPU_IRQS) = 0x0001;
37	SyncExBus();
38}
39
40static void asb2364_fpga_unmask(struct irq_data *d)
41{
42	ASB2364_FPGA_REG_MASK(d->irq - NR_CPU_IRQS) = 0x0000;
43	SyncExBus();
44}
45
46static struct irq_chip asb2364_fpga_pic = {
47	.name		= "fpga",
48	.irq_ack	= asb2364_fpga_ack,
49	.irq_mask	= asb2364_fpga_mask,
50	.irq_mask_ack	= asb2364_fpga_mask_ack,
51	.irq_unmask	= asb2364_fpga_unmask,
52};
53
54/*
55 * FPGA PIC interrupt handler
56 */
57static irqreturn_t fpga_interrupt(int irq, void *_mask)
58{
59	if ((ASB2364_FPGA_REG_IRQ_LAN  & 0x0001) != 0x0001)
60		generic_handle_irq(FPGA_LAN_IRQ);
61	if ((ASB2364_FPGA_REG_IRQ_UART & 0x0001) != 0x0001)
62		generic_handle_irq(FPGA_UART_IRQ);
63	if ((ASB2364_FPGA_REG_IRQ_I2C  & 0x0001) != 0x0001)
64		generic_handle_irq(FPGA_I2C_IRQ);
65	if ((ASB2364_FPGA_REG_IRQ_USB  & 0x0001) != 0x0001)
66		generic_handle_irq(FPGA_USB_IRQ);
67	if ((ASB2364_FPGA_REG_IRQ_FPGA & 0x0001) != 0x0001)
68		generic_handle_irq(FPGA_FPGA_IRQ);
69
70	return IRQ_HANDLED;
71}
72
73/*
74 * Define an interrupt action for each FPGA PIC output
75 */
76static struct irqaction fpga_irq[]  = {
77	[0] = {
78		.handler	= fpga_interrupt,
79		.flags		= IRQF_SHARED,
80		.name		= "fpga",
81	},
82};
83
84/*
85 * Initialise the FPGA's PIC
86 */
87void __init irq_fpga_init(void)
88{
89	int irq;
90
91	ASB2364_FPGA_REG_MASK_LAN  = 0x0001;
92	SyncExBus();
93	ASB2364_FPGA_REG_MASK_UART = 0x0001;
94	SyncExBus();
95	ASB2364_FPGA_REG_MASK_I2C  = 0x0001;
96	SyncExBus();
97	ASB2364_FPGA_REG_MASK_USB  = 0x0001;
98	SyncExBus();
99	ASB2364_FPGA_REG_MASK_FPGA = 0x0001;
100	SyncExBus();
101
102	for (irq = NR_CPU_IRQS; irq < NR_IRQS; irq++)
103		irq_set_chip_and_handler(irq, &asb2364_fpga_pic,
104					 handle_level_irq);
105
106	/* the FPGA drives the XIRQ1 input on the CPU PIC */
107	setup_irq(XIRQ1, &fpga_irq[0]);
108}
109