Linux Kernel  3.7.1
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intc.c
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1 /*
2  * intc.c -- support for the old ColdFire interrupt controller
3  *
4  * (C) Copyright 2009, Greg Ungerer <[email protected]>
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License. See the file COPYING in the main directory of this archive
8  * for more details.
9  */
10 
11 #include <linux/types.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/io.h>
17 #include <asm/traps.h>
18 #include <asm/coldfire.h>
19 #include <asm/mcfsim.h>
20 
21 /*
22  * The mapping of irq number to a mask register bit is not one-to-one.
23  * The irq numbers are either based on "level" of interrupt or fixed
24  * for an autovector-able interrupt. So we keep a local data structure
25  * that maps from irq to mask register. Not all interrupts will have
26  * an IMR bit.
27  */
28 unsigned char mcf_irq2imr[NR_IRQS];
29 
30 /*
31  * Define the miniumun and maximum external interrupt numbers.
32  * This is also used as the "level" interrupt numbers.
33  */
34 #define EIRQ1 25
35 #define EIRQ7 31
36 
37 /*
38  * In the early version 2 core ColdFire parts the IMR register was 16 bits
39  * in size. Version 3 (and later version 2) core parts have a 32 bit
40  * sized IMR register. Provide some size independent methods to access the
41  * IMR register.
42  */
43 #ifdef MCFSIM_IMR_IS_16BITS
44 
45 void mcf_setimr(int index)
46 {
47  u16 imr;
48  imr = __raw_readw(MCFSIM_IMR);
49  __raw_writew(imr | (0x1 << index), MCFSIM_IMR);
50 }
51 
52 void mcf_clrimr(int index)
53 {
54  u16 imr;
55  imr = __raw_readw(MCFSIM_IMR);
56  __raw_writew(imr & ~(0x1 << index), MCFSIM_IMR);
57 }
58 
59 void mcf_maskimr(unsigned int mask)
60 {
61  u16 imr;
62  imr = __raw_readw(MCFSIM_IMR);
63  imr |= mask;
65 }
66 
67 #else
68 
69 void mcf_setimr(int index)
70 {
71  u32 imr;
72  imr = __raw_readl(MCFSIM_IMR);
73  __raw_writel(imr | (0x1 << index), MCFSIM_IMR);
74 }
75 
76 void mcf_clrimr(int index)
77 {
78  u32 imr;
79  imr = __raw_readl(MCFSIM_IMR);
80  __raw_writel(imr & ~(0x1 << index), MCFSIM_IMR);
81 }
82 
83 void mcf_maskimr(unsigned int mask)
84 {
85  u32 imr;
86  imr = __raw_readl(MCFSIM_IMR);
87  imr |= mask;
89 }
90 
91 #endif
92 
93 /*
94  * Interrupts can be "vectored" on the ColdFire cores that support this old
95  * interrupt controller. That is, the device raising the interrupt can also
96  * supply the vector number to interrupt through. The AVR register of the
97  * interrupt controller enables or disables this for each external interrupt,
98  * so provide generic support for this. Setting this up is out-of-band for
99  * the interrupt system API's, and needs to be done by the driver that
100  * supports this device. Very few devices actually use this.
101  */
102 void mcf_autovector(int irq)
103 {
104 #ifdef MCFSIM_AVR
105  if ((irq >= EIRQ1) && (irq <= EIRQ7)) {
106  u8 avec;
107  avec = __raw_readb(MCFSIM_AVR);
108  avec |= (0x1 << (irq - EIRQ1 + 1));
109  __raw_writeb(avec, MCFSIM_AVR);
110  }
111 #endif
112 }
113 
114 static void intc_irq_mask(struct irq_data *d)
115 {
116  if (mcf_irq2imr[d->irq])
118 }
119 
120 static void intc_irq_unmask(struct irq_data *d)
121 {
122  if (mcf_irq2imr[d->irq])
124 }
125 
126 static int intc_irq_set_type(struct irq_data *d, unsigned int type)
127 {
128  return 0;
129 }
130 
131 static struct irq_chip intc_irq_chip = {
132  .name = "CF-INTC",
133  .irq_mask = intc_irq_mask,
134  .irq_unmask = intc_irq_unmask,
135  .irq_set_type = intc_irq_set_type,
136 };
137 
138 void __init init_IRQ(void)
139 {
140  int irq;
141 
142  mcf_maskimr(0xffffffff);
143 
144  for (irq = 0; (irq < NR_IRQS); irq++) {
145  irq_set_chip(irq, &intc_irq_chip);
147  irq_set_handler(irq, handle_level_irq);
148  }
149 }
150