1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
2 /*
3  * Microsemi Ocelot IRQ controller driver
4  *
5  * Copyright (c) 2017 Microsemi Corporation
6  */
7 #include <linux/bitops.h>
8 #include <linux/irq.h>
9 #include <linux/of_address.h>
10 #include <linux/of_irq.h>
11 #include <linux/irqchip.h>
12 #include <linux/irqchip/chained_irq.h>
13 #include <linux/interrupt.h>
14 
15 #define ICPU_CFG_INTR_INTR_STICKY	0x10
16 #define ICPU_CFG_INTR_INTR_ENA		0x18
17 #define ICPU_CFG_INTR_INTR_ENA_CLR	0x1c
18 #define ICPU_CFG_INTR_INTR_ENA_SET	0x20
19 #define ICPU_CFG_INTR_DST_INTR_IDENT(x)	(0x38 + 0x4 * (x))
20 #define ICPU_CFG_INTR_INTR_TRIGGER(x)	(0x5c + 0x4 * (x))
21 
22 #define OCELOT_NR_IRQ 24
23 
24 static void ocelot_irq_unmask(struct irq_data *data)
25 {
26 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
27 	struct irq_chip_type *ct = irq_data_get_chip_type(data);
28 	unsigned int mask = data->mask;
29 	u32 val;
30 
31 	irq_gc_lock(gc);
32 	val = irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(0)) |
33 	      irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(1));
34 	if (!(val & mask))
35 		irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_STICKY);
36 
37 	*ct->mask_cache &= ~mask;
38 	irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_ENA_SET);
39 	irq_gc_unlock(gc);
40 }
41 
42 static void ocelot_irq_handler(struct irq_desc *desc)
43 {
44 	struct irq_chip *chip = irq_desc_get_chip(desc);
45 	struct irq_domain *d = irq_desc_get_handler_data(desc);
46 	struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, 0);
47 	u32 reg = irq_reg_readl(gc, ICPU_CFG_INTR_DST_INTR_IDENT(0));
48 
49 	chained_irq_enter(chip, desc);
50 
51 	while (reg) {
52 		u32 hwirq = __fls(reg);
53 
54 		generic_handle_irq(irq_find_mapping(d, hwirq));
55 		reg &= ~(BIT(hwirq));
56 	}
57 
58 	chained_irq_exit(chip, desc);
59 }
60 
61 static int __init ocelot_irq_init(struct device_node *node,
62 				  struct device_node *parent)
63 {
64 	struct irq_domain *domain;
65 	struct irq_chip_generic *gc;
66 	int parent_irq, ret;
67 
68 	parent_irq = irq_of_parse_and_map(node, 0);
69 	if (!parent_irq)
70 		return -EINVAL;
71 
72 	domain = irq_domain_add_linear(node, OCELOT_NR_IRQ,
73 				       &irq_generic_chip_ops, NULL);
74 	if (!domain) {
75 		pr_err("%s: unable to add irq domain\n", node->name);
76 		return -ENOMEM;
77 	}
78 
79 	ret = irq_alloc_domain_generic_chips(domain, OCELOT_NR_IRQ, 1,
80 					     "icpu", handle_level_irq,
81 					     0, 0, 0);
82 	if (ret) {
83 		pr_err("%s: unable to alloc irq domain gc\n", node->name);
84 		goto err_domain_remove;
85 	}
86 
87 	gc = irq_get_domain_generic_chip(domain, 0);
88 	gc->reg_base = of_iomap(node, 0);
89 	if (!gc->reg_base) {
90 		pr_err("%s: unable to map resource\n", node->name);
91 		ret = -ENOMEM;
92 		goto err_gc_free;
93 	}
94 
95 	gc->chip_types[0].regs.ack = ICPU_CFG_INTR_INTR_STICKY;
96 	gc->chip_types[0].regs.mask = ICPU_CFG_INTR_INTR_ENA_CLR;
97 	gc->chip_types[0].chip.irq_ack = irq_gc_ack_set_bit;
98 	gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
99 	gc->chip_types[0].chip.irq_unmask = ocelot_irq_unmask;
100 
101 	/* Mask and ack all interrupts */
102 	irq_reg_writel(gc, 0, ICPU_CFG_INTR_INTR_ENA);
103 	irq_reg_writel(gc, 0xffffffff, ICPU_CFG_INTR_INTR_STICKY);
104 
105 	irq_set_chained_handler_and_data(parent_irq, ocelot_irq_handler,
106 					 domain);
107 
108 	return 0;
109 
110 err_gc_free:
111 	irq_free_generic_chip(gc);
112 
113 err_domain_remove:
114 	irq_domain_remove(domain);
115 
116 	return ret;
117 }
118 IRQCHIP_DECLARE(ocelot_icpu, "mscc,ocelot-icpu-intr", ocelot_irq_init);
119