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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * arch/powerpc/platforms/embedded6xx/flipper-pic.c
4  *
5  * Nintendo GameCube/Wii "Flipper" interrupt controller support.
6  * Copyright (C) 2004-2009 The GameCube Linux Team
7  * Copyright (C) 2007,2008,2009 Albert Herranz
8  */
9 #define DRV_MODULE_NAME "flipper-pic"
10 #define pr_fmt(fmt) DRV_MODULE_NAME ": " fmt
11 
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/irq.h>
15 #include <linux/of.h>
16 #include <linux/of_address.h>
17 #include <asm/io.h>
18 
19 #include "flipper-pic.h"
20 
21 #define FLIPPER_NR_IRQS		32
22 
23 /*
24  * Each interrupt has a corresponding bit in both
25  * the Interrupt Cause (ICR) and Interrupt Mask (IMR) registers.
26  *
27  * Enabling/disabling an interrupt line involves setting/clearing
28  * the corresponding bit in IMR.
29  * Except for the RSW interrupt, all interrupts get deasserted automatically
30  * when the source deasserts the interrupt.
31  */
32 #define FLIPPER_ICR		0x00
33 #define FLIPPER_ICR_RSS		(1<<16) /* reset switch state */
34 
35 #define FLIPPER_IMR		0x04
36 
37 #define FLIPPER_RESET		0x24
38 
39 
40 /*
41  * IRQ chip hooks.
42  *
43  */
44 
flipper_pic_mask_and_ack(struct irq_data * d)45 static void flipper_pic_mask_and_ack(struct irq_data *d)
46 {
47 	int irq = irqd_to_hwirq(d);
48 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
49 	u32 mask = 1 << irq;
50 
51 	clrbits32(io_base + FLIPPER_IMR, mask);
52 	/* this is at least needed for RSW */
53 	out_be32(io_base + FLIPPER_ICR, mask);
54 }
55 
flipper_pic_ack(struct irq_data * d)56 static void flipper_pic_ack(struct irq_data *d)
57 {
58 	int irq = irqd_to_hwirq(d);
59 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
60 
61 	/* this is at least needed for RSW */
62 	out_be32(io_base + FLIPPER_ICR, 1 << irq);
63 }
64 
flipper_pic_mask(struct irq_data * d)65 static void flipper_pic_mask(struct irq_data *d)
66 {
67 	int irq = irqd_to_hwirq(d);
68 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
69 
70 	clrbits32(io_base + FLIPPER_IMR, 1 << irq);
71 }
72 
flipper_pic_unmask(struct irq_data * d)73 static void flipper_pic_unmask(struct irq_data *d)
74 {
75 	int irq = irqd_to_hwirq(d);
76 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
77 
78 	setbits32(io_base + FLIPPER_IMR, 1 << irq);
79 }
80 
81 
82 static struct irq_chip flipper_pic = {
83 	.name		= "flipper-pic",
84 	.irq_ack	= flipper_pic_ack,
85 	.irq_mask_ack	= flipper_pic_mask_and_ack,
86 	.irq_mask	= flipper_pic_mask,
87 	.irq_unmask	= flipper_pic_unmask,
88 };
89 
90 /*
91  * IRQ host hooks.
92  *
93  */
94 
95 static struct irq_domain *flipper_irq_host;
96 
flipper_pic_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hwirq)97 static int flipper_pic_map(struct irq_domain *h, unsigned int virq,
98 			   irq_hw_number_t hwirq)
99 {
100 	irq_set_chip_data(virq, h->host_data);
101 	irq_set_status_flags(virq, IRQ_LEVEL);
102 	irq_set_chip_and_handler(virq, &flipper_pic, handle_level_irq);
103 	return 0;
104 }
105 
106 static const struct irq_domain_ops flipper_irq_domain_ops = {
107 	.map = flipper_pic_map,
108 };
109 
110 /*
111  * Platform hooks.
112  *
113  */
114 
__flipper_quiesce(void __iomem * io_base)115 static void __flipper_quiesce(void __iomem *io_base)
116 {
117 	/* mask and ack all IRQs */
118 	out_be32(io_base + FLIPPER_IMR, 0x00000000);
119 	out_be32(io_base + FLIPPER_ICR, 0xffffffff);
120 }
121 
flipper_pic_init(struct device_node * np)122 static struct irq_domain * __init flipper_pic_init(struct device_node *np)
123 {
124 	struct device_node *pi;
125 	struct irq_domain *irq_domain = NULL;
126 	struct resource res;
127 	void __iomem *io_base;
128 	int retval;
129 
130 	pi = of_get_parent(np);
131 	if (!pi) {
132 		pr_err("no parent found\n");
133 		goto out;
134 	}
135 	if (!of_device_is_compatible(pi, "nintendo,flipper-pi")) {
136 		pr_err("unexpected parent compatible\n");
137 		goto out;
138 	}
139 
140 	retval = of_address_to_resource(pi, 0, &res);
141 	if (retval) {
142 		pr_err("no io memory range found\n");
143 		goto out;
144 	}
145 	io_base = ioremap(res.start, resource_size(&res));
146 
147 	pr_info("controller at 0x%08x mapped to 0x%p\n", res.start, io_base);
148 
149 	__flipper_quiesce(io_base);
150 
151 	irq_domain = irq_domain_add_linear(np, FLIPPER_NR_IRQS,
152 				  &flipper_irq_domain_ops, io_base);
153 	if (!irq_domain) {
154 		pr_err("failed to allocate irq_domain\n");
155 		return NULL;
156 	}
157 
158 out:
159 	return irq_domain;
160 }
161 
flipper_pic_get_irq(void)162 unsigned int flipper_pic_get_irq(void)
163 {
164 	void __iomem *io_base = flipper_irq_host->host_data;
165 	int irq;
166 	u32 irq_status;
167 
168 	irq_status = in_be32(io_base + FLIPPER_ICR) &
169 		     in_be32(io_base + FLIPPER_IMR);
170 	if (irq_status == 0)
171 		return 0;	/* no more IRQs pending */
172 
173 	irq = __ffs(irq_status);
174 	return irq_linear_revmap(flipper_irq_host, irq);
175 }
176 
177 /*
178  * Probe function.
179  *
180  */
181 
flipper_pic_probe(void)182 void __init flipper_pic_probe(void)
183 {
184 	struct device_node *np;
185 
186 	np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-pic");
187 	BUG_ON(!np);
188 
189 	flipper_irq_host = flipper_pic_init(np);
190 	BUG_ON(!flipper_irq_host);
191 
192 	irq_set_default_host(flipper_irq_host);
193 
194 	of_node_put(np);
195 }
196 
197 /*
198  * Misc functions related to the flipper chipset.
199  *
200  */
201 
202 /**
203  * flipper_quiesce() - quiesce flipper irq controller
204  *
205  * Mask and ack all interrupt sources.
206  *
207  */
flipper_quiesce(void)208 void flipper_quiesce(void)
209 {
210 	void __iomem *io_base = flipper_irq_host->host_data;
211 
212 	__flipper_quiesce(io_base);
213 }
214 
215 /*
216  * Resets the platform.
217  */
flipper_platform_reset(void)218 void flipper_platform_reset(void)
219 {
220 	void __iomem *io_base;
221 
222 	if (flipper_irq_host && flipper_irq_host->host_data) {
223 		io_base = flipper_irq_host->host_data;
224 		out_8(io_base + FLIPPER_RESET, 0x00);
225 	}
226 }
227 
228 /*
229  * Returns non-zero if the reset button is pressed.
230  */
flipper_is_reset_button_pressed(void)231 int flipper_is_reset_button_pressed(void)
232 {
233 	void __iomem *io_base;
234 	u32 icr;
235 
236 	if (flipper_irq_host && flipper_irq_host->host_data) {
237 		io_base = flipper_irq_host->host_data;
238 		icr = in_be32(io_base + FLIPPER_ICR);
239 		return !(icr & FLIPPER_ICR_RSS);
240 	}
241 	return 0;
242 }
243 
244