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 const struct irq_domain_ops flipper_irq_domain_ops = {
112 	.map = flipper_pic_map,
113 };
114 
115 /*
116  * Platform hooks.
117  *
118  */
119 
120 static void __flipper_quiesce(void __iomem *io_base)
121 {
122 	/* mask and ack all IRQs */
123 	out_be32(io_base + FLIPPER_IMR, 0x00000000);
124 	out_be32(io_base + FLIPPER_ICR, 0xffffffff);
125 }
126 
127 static struct irq_domain * __init flipper_pic_init(struct device_node *np)
128 {
129 	struct device_node *pi;
130 	struct irq_domain *irq_domain = NULL;
131 	struct resource res;
132 	void __iomem *io_base;
133 	int retval;
134 
135 	pi = of_get_parent(np);
136 	if (!pi) {
137 		pr_err("no parent found\n");
138 		goto out;
139 	}
140 	if (!of_device_is_compatible(pi, "nintendo,flipper-pi")) {
141 		pr_err("unexpected parent compatible\n");
142 		goto out;
143 	}
144 
145 	retval = of_address_to_resource(pi, 0, &res);
146 	if (retval) {
147 		pr_err("no io memory range found\n");
148 		goto out;
149 	}
150 	io_base = ioremap(res.start, resource_size(&res));
151 
152 	pr_info("controller at 0x%08x mapped to 0x%p\n", res.start, io_base);
153 
154 	__flipper_quiesce(io_base);
155 
156 	irq_domain = irq_domain_add_linear(np, FLIPPER_NR_IRQS,
157 				  &flipper_irq_domain_ops, io_base);
158 	if (!irq_domain) {
159 		pr_err("failed to allocate irq_domain\n");
160 		return NULL;
161 	}
162 
163 out:
164 	return irq_domain;
165 }
166 
167 unsigned int flipper_pic_get_irq(void)
168 {
169 	void __iomem *io_base = flipper_irq_host->host_data;
170 	int irq;
171 	u32 irq_status;
172 
173 	irq_status = in_be32(io_base + FLIPPER_ICR) &
174 		     in_be32(io_base + FLIPPER_IMR);
175 	if (irq_status == 0)
176 		return 0;	/* no more IRQs pending */
177 
178 	irq = __ffs(irq_status);
179 	return irq_linear_revmap(flipper_irq_host, irq);
180 }
181 
182 /*
183  * Probe function.
184  *
185  */
186 
187 void __init flipper_pic_probe(void)
188 {
189 	struct device_node *np;
190 
191 	np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-pic");
192 	BUG_ON(!np);
193 
194 	flipper_irq_host = flipper_pic_init(np);
195 	BUG_ON(!flipper_irq_host);
196 
197 	irq_set_default_host(flipper_irq_host);
198 
199 	of_node_put(np);
200 }
201 
202 /*
203  * Misc functions related to the flipper chipset.
204  *
205  */
206 
207 /**
208  * flipper_quiesce() - quiesce flipper irq controller
209  *
210  * Mask and ack all interrupt sources.
211  *
212  */
213 void flipper_quiesce(void)
214 {
215 	void __iomem *io_base = flipper_irq_host->host_data;
216 
217 	__flipper_quiesce(io_base);
218 }
219 
220 /*
221  * Resets the platform.
222  */
223 void flipper_platform_reset(void)
224 {
225 	void __iomem *io_base;
226 
227 	if (flipper_irq_host && flipper_irq_host->host_data) {
228 		io_base = flipper_irq_host->host_data;
229 		out_8(io_base + FLIPPER_RESET, 0x00);
230 	}
231 }
232 
233 /*
234  * Returns non-zero if the reset button is pressed.
235  */
236 int flipper_is_reset_button_pressed(void)
237 {
238 	void __iomem *io_base;
239 	u32 icr;
240 
241 	if (flipper_irq_host && flipper_irq_host->host_data) {
242 		io_base = flipper_irq_host->host_data;
243 		icr = in_be32(io_base + FLIPPER_ICR);
244 		return !(icr & FLIPPER_ICR_RSS);
245 	}
246 	return 0;
247 }
248 
249