1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/*
* Copyright (C) 2011-12 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/irqdomain.h>
#include <linux/irqchip.h>
#include <asm/irq.h>
#define NR_CPU_IRQS 32 /* number of irq lines coming in */
#define TIMER0_IRQ 3 /* Fixed by ISA */
/*
* Early Hardware specific Interrupt setup
* -Platform independent, needed for each CPU (not foldable into init_IRQ)
* -Called very early (start_kernel -> setup_arch -> setup_processor)
*
* what it does ?
* -Optionally, setup the High priority Interrupts as Level 2 IRQs
*/
void arc_init_IRQ(void)
{
unsigned int level_mask = 0, i;
/* Is timer high priority Interrupt (Level2 in ARCompact jargon) */
level_mask |= IS_ENABLED(CONFIG_ARC_COMPACT_IRQ_LEVELS) << TIMER0_IRQ;
/*
* Write to register, even if no LV2 IRQs configured to reset it
* in case bootloader had mucked with it
*/
write_aux_reg(AUX_IRQ_LEV, level_mask);
if (level_mask)
pr_info("Level-2 interrupts bitset %x\n", level_mask);
/*
* Disable all IRQ lines so faulty external hardware won't
* trigger interrupt that kernel is not ready to handle.
*/
for (i = TIMER0_IRQ; i < NR_CPU_IRQS; i++) {
unsigned int ienb;
ienb = read_aux_reg(AUX_IENABLE);
ienb &= ~(1 << i);
write_aux_reg(AUX_IENABLE, ienb);
}
}
/*
* ARC700 core includes a simple on-chip intc supporting
* -per IRQ enable/disable
* -2 levels of interrupts (high/low)
* -all interrupts being level triggered
*
* To reduce platform code, we assume all IRQs directly hooked-up into intc.
* Platforms with external intc, hence cascaded IRQs, are free to over-ride
* below, per IRQ.
*/
static void arc_irq_mask(struct irq_data *data)
{
unsigned int ienb;
ienb = read_aux_reg(AUX_IENABLE);
ienb &= ~(1 << data->hwirq);
write_aux_reg(AUX_IENABLE, ienb);
}
static void arc_irq_unmask(struct irq_data *data)
{
unsigned int ienb;
ienb = read_aux_reg(AUX_IENABLE);
ienb |= (1 << data->hwirq);
write_aux_reg(AUX_IENABLE, ienb);
}
static struct irq_chip onchip_intc = {
.name = "ARC In-core Intc",
.irq_mask = arc_irq_mask,
.irq_unmask = arc_irq_unmask,
};
static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hw)
{
switch (hw) {
case TIMER0_IRQ:
irq_set_percpu_devid(irq);
irq_set_chip_and_handler(irq, &onchip_intc, handle_percpu_irq);
break;
default:
irq_set_chip_and_handler(irq, &onchip_intc, handle_level_irq);
}
return 0;
}
static const struct irq_domain_ops arc_intc_domain_ops = {
.xlate = irq_domain_xlate_onecell,
.map = arc_intc_domain_map,
};
static int __init
init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
{
struct irq_domain *root_domain;
if (parent)
panic("DeviceTree incore intc not a root irq controller\n");
root_domain = irq_domain_add_linear(intc, NR_CPU_IRQS,
&arc_intc_domain_ops, NULL);
if (!root_domain)
panic("root irq domain not avail\n");
/*
* Needed for primary domain lookup to succeed
* This is a primary irqchip, and can never have a parent
*/
irq_set_default_host(root_domain);
return 0;
}
IRQCHIP_DECLARE(arc_intc, "snps,arc700-intc", init_onchip_IRQ);
/*
* arch_local_irq_enable - Enable interrupts.
*
* 1. Explicitly called to re-enable interrupts
* 2. Implicitly called from spin_unlock_irq, write_unlock_irq etc
* which maybe in hard ISR itself
*
* Semantics of this function change depending on where it is called from:
*
* -If called from hard-ISR, it must not invert interrupt priorities
* e.g. suppose TIMER is high priority (Level 2) IRQ
* Time hard-ISR, timer_interrupt( ) calls spin_unlock_irq several times.
* Here local_irq_enable( ) shd not re-enable lower priority interrupts
* -If called from soft-ISR, it must re-enable all interrupts
* soft ISR are low prioity jobs which can be very slow, thus all IRQs
* must be enabled while they run.
* Now hardware context wise we may still be in L2 ISR (not done rtie)
* still we must re-enable both L1 and L2 IRQs
* Another twist is prev scenario with flow being
* L1 ISR ==> interrupted by L2 ISR ==> L2 soft ISR
* here we must not re-enable Ll as prev Ll Interrupt's h/w context will get
* over-written (this is deficiency in ARC700 Interrupt mechanism)
*/
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS /* Complex version for 2 IRQ levels */
void arch_local_irq_enable(void)
{
unsigned long flags = arch_local_save_flags();
if (flags & STATUS_A2_MASK)
flags |= STATUS_E2_MASK;
else if (flags & STATUS_A1_MASK)
flags |= STATUS_E1_MASK;
arch_local_irq_restore(flags);
}
EXPORT_SYMBOL(arch_local_irq_enable);
#endif
|
