1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
4*4882a593Smuzhiyun * Loongson HTPIC IRQ support
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun #include <linux/init.h>
8*4882a593Smuzhiyun #include <linux/of_address.h>
9*4882a593Smuzhiyun #include <linux/of_irq.h>
10*4882a593Smuzhiyun #include <linux/irqchip.h>
11*4882a593Smuzhiyun #include <linux/irqchip/chained_irq.h>
12*4882a593Smuzhiyun #include <linux/irq.h>
13*4882a593Smuzhiyun #include <linux/io.h>
14*4882a593Smuzhiyun #include <linux/syscore_ops.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include <asm/i8259.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #define HTPIC_MAX_PARENT_IRQ 4
19*4882a593Smuzhiyun #define HTINT_NUM_VECTORS 8
20*4882a593Smuzhiyun #define HTINT_EN_OFF 0x20
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun struct loongson_htpic {
23*4882a593Smuzhiyun void __iomem *base;
24*4882a593Smuzhiyun struct irq_domain *domain;
25*4882a593Smuzhiyun };
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun static struct loongson_htpic *htpic;
28*4882a593Smuzhiyun
htpic_irq_dispatch(struct irq_desc * desc)29*4882a593Smuzhiyun static void htpic_irq_dispatch(struct irq_desc *desc)
30*4882a593Smuzhiyun {
31*4882a593Smuzhiyun struct loongson_htpic *priv = irq_desc_get_handler_data(desc);
32*4882a593Smuzhiyun struct irq_chip *chip = irq_desc_get_chip(desc);
33*4882a593Smuzhiyun uint32_t pending;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun chained_irq_enter(chip, desc);
36*4882a593Smuzhiyun pending = readl(priv->base);
37*4882a593Smuzhiyun /* Ack all IRQs at once, otherwise IRQ flood might happen */
38*4882a593Smuzhiyun writel(pending, priv->base);
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun if (!pending)
41*4882a593Smuzhiyun spurious_interrupt();
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun while (pending) {
44*4882a593Smuzhiyun int bit = __ffs(pending);
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun if (unlikely(bit > 15)) {
47*4882a593Smuzhiyun spurious_interrupt();
48*4882a593Smuzhiyun break;
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun generic_handle_irq(irq_linear_revmap(priv->domain, bit));
52*4882a593Smuzhiyun pending &= ~BIT(bit);
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun chained_irq_exit(chip, desc);
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun
htpic_reg_init(void)57*4882a593Smuzhiyun static void htpic_reg_init(void)
58*4882a593Smuzhiyun {
59*4882a593Smuzhiyun int i;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun for (i = 0; i < HTINT_NUM_VECTORS; i++) {
62*4882a593Smuzhiyun uint32_t val;
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun /* Disable all HT Vectors */
65*4882a593Smuzhiyun writel(0x0, htpic->base + HTINT_EN_OFF + i * 0x4);
66*4882a593Smuzhiyun val = readl(htpic->base + i * 0x4);
67*4882a593Smuzhiyun /* Ack all possible pending IRQs */
68*4882a593Smuzhiyun writel(GENMASK(31, 0), htpic->base + i * 0x4);
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun /* Enable 16 vectors for PIC */
72*4882a593Smuzhiyun writel(0xffff, htpic->base + HTINT_EN_OFF);
73*4882a593Smuzhiyun }
74*4882a593Smuzhiyun
htpic_resume(void)75*4882a593Smuzhiyun static void htpic_resume(void)
76*4882a593Smuzhiyun {
77*4882a593Smuzhiyun htpic_reg_init();
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun struct syscore_ops htpic_syscore_ops = {
81*4882a593Smuzhiyun .resume = htpic_resume,
82*4882a593Smuzhiyun };
83*4882a593Smuzhiyun
htpic_of_init(struct device_node * node,struct device_node * parent)84*4882a593Smuzhiyun int __init htpic_of_init(struct device_node *node, struct device_node *parent)
85*4882a593Smuzhiyun {
86*4882a593Smuzhiyun unsigned int parent_irq[4];
87*4882a593Smuzhiyun int i, err;
88*4882a593Smuzhiyun int num_parents = 0;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun if (htpic) {
91*4882a593Smuzhiyun pr_err("loongson-htpic: Only one HTPIC is allowed in the system\n");
92*4882a593Smuzhiyun return -ENODEV;
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun htpic = kzalloc(sizeof(*htpic), GFP_KERNEL);
96*4882a593Smuzhiyun if (!htpic)
97*4882a593Smuzhiyun return -ENOMEM;
98*4882a593Smuzhiyun
99*4882a593Smuzhiyun htpic->base = of_iomap(node, 0);
100*4882a593Smuzhiyun if (!htpic->base) {
101*4882a593Smuzhiyun err = -ENODEV;
102*4882a593Smuzhiyun goto out_free;
103*4882a593Smuzhiyun }
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun htpic->domain = __init_i8259_irqs(node);
106*4882a593Smuzhiyun if (!htpic->domain) {
107*4882a593Smuzhiyun pr_err("loongson-htpic: Failed to initialize i8259 IRQs\n");
108*4882a593Smuzhiyun err = -ENOMEM;
109*4882a593Smuzhiyun goto out_iounmap;
110*4882a593Smuzhiyun }
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun /* Interrupt may come from any of the 4 interrupt line */
113*4882a593Smuzhiyun for (i = 0; i < HTPIC_MAX_PARENT_IRQ; i++) {
114*4882a593Smuzhiyun parent_irq[i] = irq_of_parse_and_map(node, i);
115*4882a593Smuzhiyun if (parent_irq[i] <= 0)
116*4882a593Smuzhiyun break;
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun num_parents++;
119*4882a593Smuzhiyun }
120*4882a593Smuzhiyun
121*4882a593Smuzhiyun if (!num_parents) {
122*4882a593Smuzhiyun pr_err("loongson-htpic: Failed to get parent irqs\n");
123*4882a593Smuzhiyun err = -ENODEV;
124*4882a593Smuzhiyun goto out_remove_domain;
125*4882a593Smuzhiyun }
126*4882a593Smuzhiyun
127*4882a593Smuzhiyun htpic_reg_init();
128*4882a593Smuzhiyun
129*4882a593Smuzhiyun for (i = 0; i < num_parents; i++) {
130*4882a593Smuzhiyun irq_set_chained_handler_and_data(parent_irq[i],
131*4882a593Smuzhiyun htpic_irq_dispatch, htpic);
132*4882a593Smuzhiyun }
133*4882a593Smuzhiyun
134*4882a593Smuzhiyun register_syscore_ops(&htpic_syscore_ops);
135*4882a593Smuzhiyun
136*4882a593Smuzhiyun return 0;
137*4882a593Smuzhiyun
138*4882a593Smuzhiyun out_remove_domain:
139*4882a593Smuzhiyun irq_domain_remove(htpic->domain);
140*4882a593Smuzhiyun out_iounmap:
141*4882a593Smuzhiyun iounmap(htpic->base);
142*4882a593Smuzhiyun out_free:
143*4882a593Smuzhiyun kfree(htpic);
144*4882a593Smuzhiyun return err;
145*4882a593Smuzhiyun }
146*4882a593Smuzhiyun
147*4882a593Smuzhiyun IRQCHIP_DECLARE(loongson_htpic, "loongson,htpic-1.0", htpic_of_init);
148