1 /*
2  * arch/powerpc/platforms/embedded6xx/flipper-pic.c
3  *
4  * Nintendo GameCube/Wii "Flipper" interrupt controller support.
5  * Copyright (C) 2004-2009 The GameCube Linux Team
6  * Copyright (C) 2007,2008,2009 Albert Herranz
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * as published by the Free Software Foundation; either version 2
11  * of the License, or (at your option) any later version.
12  *
13  */
14 #define DRV_MODULE_NAME "flipper-pic"
15 #define pr_fmt(fmt) DRV_MODULE_NAME ": " fmt
16 
17 #include <linux/kernel.h>
18 #include <linux/init.h>
19 #include <linux/irq.h>
20 #include <linux/of.h>
21 #include <linux/of_address.h>
22 #include <asm/io.h>
23 
24 #include "flipper-pic.h"
25 
26 #define FLIPPER_NR_IRQS		32
27 
28 /*
29  * Each interrupt has a corresponding bit in both
30  * the Interrupt Cause (ICR) and Interrupt Mask (IMR) registers.
31  *
32  * Enabling/disabling an interrupt line involves setting/clearing
33  * the corresponding bit in IMR.
34  * Except for the RSW interrupt, all interrupts get deasserted automatically
35  * when the source deasserts the interrupt.
36  */
37 #define FLIPPER_ICR		0x00
38 #define FLIPPER_ICR_RSS		(1<<16) /* reset switch state */
39 
40 #define FLIPPER_IMR		0x04
41 
42 #define FLIPPER_RESET		0x24
43 
44 
45 /*
46  * IRQ chip hooks.
47  *
48  */
49 
50 static void flipper_pic_mask_and_ack(struct irq_data *d)
51 {
52 	int irq = irqd_to_hwirq(d);
53 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
54 	u32 mask = 1 << irq;
55 
56 	clrbits32(io_base + FLIPPER_IMR, mask);
57 	/* this is at least needed for RSW */
58 	out_be32(io_base + FLIPPER_ICR, mask);
59 }
60 
61 static void flipper_pic_ack(struct irq_data *d)
62 {
63 	int irq = irqd_to_hwirq(d);
64 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
65 
66 	/* this is at least needed for RSW */
67 	out_be32(io_base + FLIPPER_ICR, 1 << irq);
68 }
69 
70 static void flipper_pic_mask(struct irq_data *d)
71 {
72 	int irq = irqd_to_hwirq(d);
73 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
74 
75 	clrbits32(io_base + FLIPPER_IMR, 1 << irq);
76 }
77 
78 static void flipper_pic_unmask(struct irq_data *d)
79 {
80 	int irq = irqd_to_hwirq(d);
81 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
82 
83 	setbits32(io_base + FLIPPER_IMR, 1 << irq);
84 }
85 
86 
87 static struct irq_chip flipper_pic = {
88 	.name		= "flipper-pic",
89 	.irq_ack	= flipper_pic_ack,
90 	.irq_mask_ack	= flipper_pic_mask_and_ack,
91 	.irq_mask	= flipper_pic_mask,
92 	.irq_unmask	= flipper_pic_unmask,
93 };
94 
95 /*
96  * IRQ host hooks.
97  *
98  */
99 
100 static struct irq_domain *flipper_irq_host;
101 
102 static int flipper_pic_map(struct irq_domain *h, unsigned int virq,
103 			   irq_hw_number_t hwirq)
104 {
105 	irq_set_chip_data(virq, h->host_data);
106 	irq_set_status_flags(virq, IRQ_LEVEL);
107 	irq_set_chip_and_handler(virq, &flipper_pic, handle_level_irq);
108 	return 0;
109 }
110 
111 static int flipper_pic_match(struct irq_domain *h, struct device_node *np,
112 			     enum irq_domain_bus_token bus_token)
113 {
114 	return 1;
115 }
116 
117 
118 static const struct irq_domain_ops flipper_irq_domain_ops = {
119 	.map = flipper_pic_map,
120 	.match = flipper_pic_match,
121 };
122 
123 /*
124  * Platform hooks.
125  *
126  */
127 
128 static void __flipper_quiesce(void __iomem *io_base)
129 {
130 	/* mask and ack all IRQs */
131 	out_be32(io_base + FLIPPER_IMR, 0x00000000);
132 	out_be32(io_base + FLIPPER_ICR, 0xffffffff);
133 }
134 
135 struct irq_domain * __init flipper_pic_init(struct device_node *np)
136 {
137 	struct device_node *pi;
138 	struct irq_domain *irq_domain = NULL;
139 	struct resource res;
140 	void __iomem *io_base;
141 	int retval;
142 
143 	pi = of_get_parent(np);
144 	if (!pi) {
145 		pr_err("no parent found\n");
146 		goto out;
147 	}
148 	if (!of_device_is_compatible(pi, "nintendo,flipper-pi")) {
149 		pr_err("unexpected parent compatible\n");
150 		goto out;
151 	}
152 
153 	retval = of_address_to_resource(pi, 0, &res);
154 	if (retval) {
155 		pr_err("no io memory range found\n");
156 		goto out;
157 	}
158 	io_base = ioremap(res.start, resource_size(&res));
159 
160 	pr_info("controller at 0x%08x mapped to 0x%p\n", res.start, io_base);
161 
162 	__flipper_quiesce(io_base);
163 
164 	irq_domain = irq_domain_add_linear(np, FLIPPER_NR_IRQS,
165 				  &flipper_irq_domain_ops, io_base);
166 	if (!irq_domain) {
167 		pr_err("failed to allocate irq_domain\n");
168 		return NULL;
169 	}
170 
171 out:
172 	return irq_domain;
173 }
174 
175 unsigned int flipper_pic_get_irq(void)
176 {
177 	void __iomem *io_base = flipper_irq_host->host_data;
178 	int irq;
179 	u32 irq_status;
180 
181 	irq_status = in_be32(io_base + FLIPPER_ICR) &
182 		     in_be32(io_base + FLIPPER_IMR);
183 	if (irq_status == 0)
184 		return NO_IRQ;	/* no more IRQs pending */
185 
186 	irq = __ffs(irq_status);
187 	return irq_linear_revmap(flipper_irq_host, irq);
188 }
189 
190 /*
191  * Probe function.
192  *
193  */
194 
195 void __init flipper_pic_probe(void)
196 {
197 	struct device_node *np;
198 
199 	np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-pic");
200 	BUG_ON(!np);
201 
202 	flipper_irq_host = flipper_pic_init(np);
203 	BUG_ON(!flipper_irq_host);
204 
205 	irq_set_default_host(flipper_irq_host);
206 
207 	of_node_put(np);
208 }
209 
210 /*
211  * Misc functions related to the flipper chipset.
212  *
213  */
214 
215 /**
216  * flipper_quiesce() - quiesce flipper irq controller
217  *
218  * Mask and ack all interrupt sources.
219  *
220  */
221 void flipper_quiesce(void)
222 {
223 	void __iomem *io_base = flipper_irq_host->host_data;
224 
225 	__flipper_quiesce(io_base);
226 }
227 
228 /*
229  * Resets the platform.
230  */
231 void flipper_platform_reset(void)
232 {
233 	void __iomem *io_base;
234 
235 	if (flipper_irq_host && flipper_irq_host->host_data) {
236 		io_base = flipper_irq_host->host_data;
237 		out_8(io_base + FLIPPER_RESET, 0x00);
238 	}
239 }
240 
241 /*
242  * Returns non-zero if the reset button is pressed.
243  */
244 int flipper_is_reset_button_pressed(void)
245 {
246 	void __iomem *io_base;
247 	u32 icr;
248 
249 	if (flipper_irq_host && flipper_irq_host->host_data) {
250 		io_base = flipper_irq_host->host_data;
251 		icr = in_be32(io_base + FLIPPER_ICR);
252 		return !(icr & FLIPPER_ICR_RSS);
253 	}
254 	return 0;
255 }
256 
257