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
26 static 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
handle_jcore_irq(struct irq_desc * desc)38 static void handle_jcore_irq(struct irq_desc *desc)
39 {
40 if (irqd_is_per_cpu(irq_desc_get_irq_data(desc)))
41 handle_percpu_irq(desc);
42 else
43 handle_simple_irq(desc);
44 }
45
jcore_aic_irqdomain_map(struct irq_domain * d,unsigned int irq,irq_hw_number_t hwirq)46 static 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
56 static const struct irq_domain_ops jcore_aic_irqdomain_ops = {
57 .map = jcore_aic_irqdomain_map,
58 .xlate = irq_domain_xlate_onecell,
59 };
60
noop(struct irq_data * data)61 static void noop(struct irq_data *data)
62 {
63 }
64
aic_irq_of_init(struct device_node * node,struct device_node * parent)65 static 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
72 pr_info("Initializing J-Core AIC\n");
73
74 /* AIC1 needs priority initialization to receive interrupts. */
75 if (of_device_is_compatible(node, "jcore,aic1")) {
76 unsigned cpu;
77
78 for_each_present_cpu(cpu) {
79 void __iomem *base = of_iomap(node, cpu);
80
81 if (!base) {
82 pr_err("Unable to map AIC for cpu %u\n", cpu);
83 return -ENOMEM;
84 }
85 __raw_writel(0xffffffff, base + JCORE_AIC1_INTPRI_REG);
86 iounmap(base);
87 }
88 min_irq = JCORE_AIC1_MIN_HWIRQ;
89 }
90
91 /*
92 * The irq chip framework requires either mask/unmask or enable/disable
93 * function pointers to be provided, but the hardware does not have any
94 * such mechanism; the only interrupt masking is at the cpu level and
95 * it affects all interrupts. We provide dummy mask/unmask. The hardware
96 * handles all interrupt control and clears pending status when the cpu
97 * accepts the interrupt.
98 */
99 jcore_aic.irq_mask = noop;
100 jcore_aic.irq_unmask = noop;
101 jcore_aic.name = "AIC";
102
103 domain = irq_domain_add_linear(node, dom_sz, &jcore_aic_irqdomain_ops,
104 &jcore_aic);
105 if (!domain)
106 return -ENOMEM;
107 irq_create_strict_mappings(domain, min_irq, min_irq, dom_sz - min_irq);
108
109 return 0;
110 }
111
112 IRQCHIP_DECLARE(jcore_aic2, "jcore,aic2", aic_irq_of_init);
113 IRQCHIP_DECLARE(jcore_aic1, "jcore,aic1", aic_irq_of_init);
114
