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 */
asb2364_fpga_mask(struct irq_data * d)20 static void asb2364_fpga_mask(struct irq_data *d)
21 {
22 ASB2364_FPGA_REG_MASK(d->irq - NR_CPU_IRQS) = 0x0001;
23 SyncExBus();
24 }
25
asb2364_fpga_ack(struct irq_data * d)26 static void asb2364_fpga_ack(struct irq_data *d)
27 {
28 ASB2364_FPGA_REG_IRQ(d->irq - NR_CPU_IRQS) = 0x0001;
29 SyncExBus();
30 }
31
asb2364_fpga_mask_ack(struct irq_data * d)32 static 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
asb2364_fpga_unmask(struct irq_data * d)40 static void asb2364_fpga_unmask(struct irq_data *d)
41 {
42 ASB2364_FPGA_REG_MASK(d->irq - NR_CPU_IRQS) = 0x0000;
43 SyncExBus();
44 }
45
46 static 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 */
fpga_interrupt(int irq,void * _mask)57 static 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 */
76 static struct irqaction fpga_irq[] = {
77 [0] = {
78 .handler = fpga_interrupt,
79 .flags = IRQF_DISABLED | IRQF_SHARED,
80 .name = "fpga",
81 },
82 };
83
84 /*
85 * Initialise the FPGA's PIC
86 */
irq_fpga_init(void)87 void __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