1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
4  * Copyright (C) 2014 Stefan Kristansson <stefan.kristiansson@saunalahti.fi>
5  */
6 
7 #include <linux/irq.h>
8 #include <linux/irqchip.h>
9 #include <linux/of.h>
10 #include <linux/of_irq.h>
11 #include <linux/of_address.h>
12 
13 /* OR1K PIC implementation */
14 
15 struct or1k_pic_dev {
16 	struct irq_chip chip;
17 	irq_flow_handler_t handle;
18 	unsigned long flags;
19 };
20 
21 /*
22  * We're a couple of cycles faster than the generic implementations with
23  * these 'fast' versions.
24  */
25 
26 static void or1k_pic_mask(struct irq_data *data)
27 {
28 	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
29 }
30 
31 static void or1k_pic_unmask(struct irq_data *data)
32 {
33 	mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (1UL << data->hwirq));
34 }
35 
36 static void or1k_pic_ack(struct irq_data *data)
37 {
38 	mtspr(SPR_PICSR, (1UL << data->hwirq));
39 }
40 
41 static void or1k_pic_mask_ack(struct irq_data *data)
42 {
43 	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
44 	mtspr(SPR_PICSR, (1UL << data->hwirq));
45 }
46 
47 /*
48  * There are two oddities with the OR1200 PIC implementation:
49  * i)  LEVEL-triggered interrupts are latched and need to be cleared
50  * ii) the interrupt latch is cleared by writing a 0 to the bit,
51  *     as opposed to a 1 as mandated by the spec
52  */
53 static void or1k_pic_or1200_ack(struct irq_data *data)
54 {
55 	mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
56 }
57 
58 static void or1k_pic_or1200_mask_ack(struct irq_data *data)
59 {
60 	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
61 	mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
62 }
63 
64 static struct or1k_pic_dev or1k_pic_level = {
65 	.chip = {
66 		.name = "or1k-PIC-level",
67 		.irq_unmask = or1k_pic_unmask,
68 		.irq_mask = or1k_pic_mask,
69 	},
70 	.handle = handle_level_irq,
71 	.flags = IRQ_LEVEL | IRQ_NOPROBE,
72 };
73 
74 static struct or1k_pic_dev or1k_pic_edge = {
75 	.chip = {
76 		.name = "or1k-PIC-edge",
77 		.irq_unmask = or1k_pic_unmask,
78 		.irq_mask = or1k_pic_mask,
79 		.irq_ack = or1k_pic_ack,
80 		.irq_mask_ack = or1k_pic_mask_ack,
81 	},
82 	.handle = handle_edge_irq,
83 	.flags = IRQ_LEVEL | IRQ_NOPROBE,
84 };
85 
86 static struct or1k_pic_dev or1k_pic_or1200 = {
87 	.chip = {
88 		.name = "or1200-PIC",
89 		.irq_unmask = or1k_pic_unmask,
90 		.irq_mask = or1k_pic_mask,
91 		.irq_ack = or1k_pic_or1200_ack,
92 		.irq_mask_ack = or1k_pic_or1200_mask_ack,
93 	},
94 	.handle = handle_level_irq,
95 	.flags = IRQ_LEVEL | IRQ_NOPROBE,
96 };
97 
98 static struct irq_domain *root_domain;
99 
100 static inline int pic_get_irq(int first)
101 {
102 	int hwirq;
103 
104 	hwirq = ffs(mfspr(SPR_PICSR) >> first);
105 	if (!hwirq)
106 		return NO_IRQ;
107 	else
108 		hwirq = hwirq + first - 1;
109 
110 	return hwirq;
111 }
112 
113 static void or1k_pic_handle_irq(struct pt_regs *regs)
114 {
115 	int irq = -1;
116 
117 	while ((irq = pic_get_irq(irq + 1)) != NO_IRQ)
118 		generic_handle_domain_irq(root_domain, irq);
119 }
120 
121 static int or1k_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
122 {
123 	struct or1k_pic_dev *pic = d->host_data;
124 
125 	irq_set_chip_and_handler(irq, &pic->chip, pic->handle);
126 	irq_set_status_flags(irq, pic->flags);
127 
128 	return 0;
129 }
130 
131 static const struct irq_domain_ops or1k_irq_domain_ops = {
132 	.xlate = irq_domain_xlate_onecell,
133 	.map = or1k_map,
134 };
135 
136 /*
137  * This sets up the IRQ domain for the PIC built in to the OpenRISC
138  * 1000 CPU.  This is the "root" domain as these are the interrupts
139  * that directly trigger an exception in the CPU.
140  */
141 static int __init or1k_pic_init(struct device_node *node,
142 				 struct or1k_pic_dev *pic)
143 {
144 	/* Disable all interrupts until explicitly requested */
145 	mtspr(SPR_PICMR, (0UL));
146 
147 	root_domain = irq_domain_add_linear(node, 32, &or1k_irq_domain_ops,
148 					    pic);
149 
150 	set_handle_irq(or1k_pic_handle_irq);
151 
152 	return 0;
153 }
154 
155 static int __init or1k_pic_or1200_init(struct device_node *node,
156 				       struct device_node *parent)
157 {
158 	return or1k_pic_init(node, &or1k_pic_or1200);
159 }
160 IRQCHIP_DECLARE(or1k_pic_or1200, "opencores,or1200-pic", or1k_pic_or1200_init);
161 IRQCHIP_DECLARE(or1k_pic, "opencores,or1k-pic", or1k_pic_or1200_init);
162 
163 static int __init or1k_pic_level_init(struct device_node *node,
164 				      struct device_node *parent)
165 {
166 	return or1k_pic_init(node, &or1k_pic_level);
167 }
168 IRQCHIP_DECLARE(or1k_pic_level, "opencores,or1k-pic-level",
169 		or1k_pic_level_init);
170 
171 static int __init or1k_pic_edge_init(struct device_node *node,
172 				     struct device_node *parent)
173 {
174 	return or1k_pic_init(node, &or1k_pic_edge);
175 }
176 IRQCHIP_DECLARE(or1k_pic_edge, "opencores,or1k-pic-edge", or1k_pic_edge_init);
177