Linux Kernel  3.7.1
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irq-fpga.c
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1 /* ASB2364 FPGA interrupt multiplexing
2  *
3  * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells ([email protected])
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  */
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 
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 
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 
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  */
57 static irqreturn_t fpga_interrupt(int irq, void *_mask)
58 {
59  if ((ASB2364_FPGA_REG_IRQ_LAN & 0x0001) != 0x0001)
61  if ((ASB2364_FPGA_REG_IRQ_UART & 0x0001) != 0x0001)
63  if ((ASB2364_FPGA_REG_IRQ_I2C & 0x0001) != 0x0001)
65  if ((ASB2364_FPGA_REG_IRQ_USB & 0x0001) != 0x0001)
67  if ((ASB2364_FPGA_REG_IRQ_FPGA & 0x0001) != 0x0001)
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  */
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,
105 
106  /* the FPGA drives the XIRQ1 input on the CPU PIC */
107  setup_irq(XIRQ1, &fpga_irq[0]);
108 }