projects/linux·blob master · refs

119 lines · 3.2 KiB

1/*
2 * J-Core SoC AIC driver
3 *
4 * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
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/irq.h>
12#include <linux/io.h>
13#include <linux/irqchip.h>
14#include <linux/irqdomain.h>
15#include <linux/cpu.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/of_irq.h>
19
20#define JCORE_AIC_MAX_HWIRQ 127
21#define JCORE_AIC1_MIN_HWIRQ 16
22#define JCORE_AIC2_MIN_HWIRQ 64
23
24#define JCORE_AIC1_INTPRI_REG 8
25
26static struct irq_chip jcore_aic;
27
28/*
29 * The J-Core AIC1 and AIC2 are cpu-local interrupt controllers and do
30 * not distinguish or use distinct irq number ranges for per-cpu event
31 * interrupts (timer, IPI). Since information to determine whether a
32 * particular irq number should be treated as per-cpu is not available
33 * at mapping time, we use a wrapper handler function which chooses
34 * the right handler at runtime based on whether IRQF_PERCPU was used
35 * when requesting the irq.
36 */
37
38static void handle_jcore_irq(struct irq_desc *desc)
39{
40 if (irqd_is_per_cpu(irq_desc_get_irq_data(desc)))
41 handle_percpu_devid_irq(desc);
42 else
43 handle_simple_irq(desc);
44}
45
46static int jcore_aic_irqdomain_map(struct irq_domain *d, unsigned int irq,
47 irq_hw_number_t hwirq)
48{
49 struct irq_chip *aic = d->host_data;
50
51 irq_set_chip_and_handler(irq, aic, handle_jcore_irq);
52
53 return 0;
54}
55
56static const struct irq_domain_ops jcore_aic_irqdomain_ops = {
57 .map = jcore_aic_irqdomain_map,
58 .xlate = irq_domain_xlate_onecell,
59};
60
61static void noop(struct irq_data *data)
62{
63}
64
65static int __init aic_irq_of_init(struct device_node *node,
66 struct device_node *parent)
67{
68 unsigned min_irq = JCORE_AIC2_MIN_HWIRQ;
69 unsigned dom_sz = JCORE_AIC_MAX_HWIRQ+1;
70 struct irq_domain *domain;
71 int ret;
72
73 pr_info("Initializing J-Core AIC\n");
74
75 /* AIC1 needs priority initialization to receive interrupts. */
76 if (of_device_is_compatible(node, "jcore,aic1")) {
77 unsigned cpu;
78
79 for_each_present_cpu(cpu) {
80 void __iomem *base = of_iomap(node, cpu);
81
82 if (!base) {
83 pr_err("Unable to map AIC for cpu %u\n", cpu);
84 return -ENOMEM;
85 }
86 __raw_writel(0xffffffff, base + JCORE_AIC1_INTPRI_REG);
87 iounmap(base);
88 }
89 min_irq = JCORE_AIC1_MIN_HWIRQ;
90 }
91
92 /*
93 * The irq chip framework requires either mask/unmask or enable/disable
94 * function pointers to be provided, but the hardware does not have any
95 * such mechanism; the only interrupt masking is at the cpu level and
96 * it affects all interrupts. We provide dummy mask/unmask. The hardware
97 * handles all interrupt control and clears pending status when the cpu
98 * accepts the interrupt.
99 */
100 jcore_aic.irq_mask = noop;
101 jcore_aic.irq_unmask = noop;
102 jcore_aic.name = "AIC";
103
104 ret = irq_alloc_descs(-1, min_irq, dom_sz - min_irq,
105 of_node_to_nid(node));
106
107 if (ret < 0)
108 return ret;
109
110 domain = irq_domain_create_legacy(of_fwnode_handle(node), dom_sz - min_irq, min_irq,
111 min_irq, &jcore_aic_irqdomain_ops, &jcore_aic);
112 if (!domain)
113 return -ENOMEM;
114
115 return 0;
116}
117
118IRQCHIP_DECLARE(jcore_aic2, "jcore,aic2", aic_irq_of_init);
119IRQCHIP_DECLARE(jcore_aic1, "jcore,aic1", aic_irq_of_init);