1 /* irq-mb93093.c: MB93093 FPGA interrupt handling
2 *
3 * Copyright (C) 2006 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #include <linux/ptrace.h>
13 #include <linux/errno.h>
14 #include <linux/signal.h>
15 #include <linux/sched.h>
16 #include <linux/ioport.h>
17 #include <linux/interrupt.h>
18 #include <linux/init.h>
19 #include <linux/irq.h>
20 #include <linux/bitops.h>
21
22 #include <asm/io.h>
23 #include <asm/system.h>
24 #include <asm/delay.h>
25 #include <asm/irq.h>
26 #include <asm/irc-regs.h>
27
28 #define __reg16(ADDR) (*(volatile unsigned short *)(__region_CS2 + (ADDR)))
29
30 #define __get_IMR() ({ __reg16(0x0a); })
31 #define __set_IMR(M) do { __reg16(0x0a) = (M); wmb(); } while(0)
32 #define __get_IFR() ({ __reg16(0x02); })
33 #define __clr_IFR(M) do { __reg16(0x02) = ~(M); wmb(); } while(0)
34
35 /*
36 * off-CPU FPGA PIC operations
37 */
frv_fpga_mask(struct irq_data * d)38 static void frv_fpga_mask(struct irq_data *d)
39 {
40 uint16_t imr = __get_IMR();
41
42 imr |= 1 << (d->irq - IRQ_BASE_FPGA);
43 __set_IMR(imr);
44 }
45
frv_fpga_ack(struct irq_data * d)46 static void frv_fpga_ack(struct irq_data *d)
47 {
48 __clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
49 }
50
frv_fpga_mask_ack(struct irq_data * d)51 static void frv_fpga_mask_ack(struct irq_data *d)
52 {
53 uint16_t imr = __get_IMR();
54
55 imr |= 1 << (d->irq - IRQ_BASE_FPGA);
56 __set_IMR(imr);
57
58 __clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
59 }
60
frv_fpga_unmask(struct irq_data * d)61 static void frv_fpga_unmask(struct irq_data *d)
62 {
63 uint16_t imr = __get_IMR();
64
65 imr &= ~(1 << (d->irq - IRQ_BASE_FPGA));
66
67 __set_IMR(imr);
68 }
69
70 static struct irq_chip frv_fpga_pic = {
71 .name = "mb93093",
72 .irq_ack = frv_fpga_ack,
73 .irq_mask = frv_fpga_mask,
74 .irq_mask_ack = frv_fpga_mask_ack,
75 .irq_unmask = frv_fpga_unmask,
76 };
77
78 /*
79 * FPGA PIC interrupt handler
80 */
fpga_interrupt(int irq,void * _mask)81 static irqreturn_t fpga_interrupt(int irq, void *_mask)
82 {
83 uint16_t imr, mask = (unsigned long) _mask;
84
85 imr = __get_IMR();
86 mask = mask & ~imr & __get_IFR();
87
88 /* poll all the triggered IRQs */
89 while (mask) {
90 int irq;
91
92 asm("scan %1,gr0,%0" : "=r"(irq) : "r"(mask));
93 irq = 31 - irq;
94 mask &= ~(1 << irq);
95
96 generic_handle_irq(IRQ_BASE_FPGA + irq);
97 }
98
99 return IRQ_HANDLED;
100 }
101
102 /*
103 * define an interrupt action for each FPGA PIC output
104 * - use dev_id to indicate the FPGA PIC input to output mappings
105 */
106 static struct irqaction fpga_irq[1] = {
107 [0] = {
108 .handler = fpga_interrupt,
109 .flags = IRQF_DISABLED,
110 .name = "fpga.0",
111 .dev_id = (void *) 0x0700UL,
112 }
113 };
114
115 /*
116 * initialise the motherboard FPGA's PIC
117 */
fpga_init(void)118 void __init fpga_init(void)
119 {
120 int irq;
121
122 /* all PIC inputs are all set to be edge triggered */
123 __set_IMR(0x0700);
124 __clr_IFR(0x0000);
125
126 for (irq = IRQ_BASE_FPGA + 8; irq <= IRQ_BASE_FPGA + 10; irq++)
127 irq_set_chip_and_handler(irq, &frv_fpga_pic, handle_edge_irq);
128
129 /* the FPGA drives external IRQ input #2 on the CPU PIC */
130 setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[0]);
131 }
132