1 /*
2  * arch/powerpc/platforms/embedded6xx/hlwd-pic.c
3  *
4  * Nintendo Wii "Hollywood" interrupt controller support.
5  * Copyright (C) 2009 The GameCube Linux Team
6  * Copyright (C) 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 "hlwd-pic"
15 #define pr_fmt(fmt) DRV_MODULE_NAME ": " fmt
16 
17 #include <linux/kernel.h>
18 #include <linux/irq.h>
19 #include <linux/of.h>
20 #include <linux/of_address.h>
21 #include <linux/of_irq.h>
22 #include <asm/io.h>
23 
24 #include "hlwd-pic.h"
25 
26 #define HLWD_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 asserting/clearing
33  * the corresponding bit in IMR. ACK'ing a request simply involves
34  * asserting the corresponding bit in ICR.
35  */
36 #define HW_BROADWAY_ICR		0x00
37 #define HW_BROADWAY_IMR		0x04
38 
39 
40 /*
41  * IRQ chip hooks.
42  *
43  */
44 
45 static void hlwd_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 + HW_BROADWAY_IMR, mask);
52 	out_be32(io_base + HW_BROADWAY_ICR, mask);
53 }
54 
55 static void hlwd_pic_ack(struct irq_data *d)
56 {
57 	int irq = irqd_to_hwirq(d);
58 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
59 
60 	out_be32(io_base + HW_BROADWAY_ICR, 1 << irq);
61 }
62 
63 static void hlwd_pic_mask(struct irq_data *d)
64 {
65 	int irq = irqd_to_hwirq(d);
66 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
67 
68 	clrbits32(io_base + HW_BROADWAY_IMR, 1 << irq);
69 }
70 
71 static void hlwd_pic_unmask(struct irq_data *d)
72 {
73 	int irq = irqd_to_hwirq(d);
74 	void __iomem *io_base = irq_data_get_irq_chip_data(d);
75 
76 	setbits32(io_base + HW_BROADWAY_IMR, 1 << irq);
77 }
78 
79 
80 static struct irq_chip hlwd_pic = {
81 	.name		= "hlwd-pic",
82 	.irq_ack	= hlwd_pic_ack,
83 	.irq_mask_ack	= hlwd_pic_mask_and_ack,
84 	.irq_mask	= hlwd_pic_mask,
85 	.irq_unmask	= hlwd_pic_unmask,
86 };
87 
88 /*
89  * IRQ host hooks.
90  *
91  */
92 
93 static struct irq_domain *hlwd_irq_host;
94 
95 static int hlwd_pic_map(struct irq_domain *h, unsigned int virq,
96 			   irq_hw_number_t hwirq)
97 {
98 	irq_set_chip_data(virq, h->host_data);
99 	irq_set_status_flags(virq, IRQ_LEVEL);
100 	irq_set_chip_and_handler(virq, &hlwd_pic, handle_level_irq);
101 	return 0;
102 }
103 
104 static const struct irq_domain_ops hlwd_irq_domain_ops = {
105 	.map = hlwd_pic_map,
106 };
107 
108 static unsigned int __hlwd_pic_get_irq(struct irq_domain *h)
109 {
110 	void __iomem *io_base = h->host_data;
111 	int irq;
112 	u32 irq_status;
113 
114 	irq_status = in_be32(io_base + HW_BROADWAY_ICR) &
115 		     in_be32(io_base + HW_BROADWAY_IMR);
116 	if (irq_status == 0)
117 		return NO_IRQ;	/* no more IRQs pending */
118 
119 	irq = __ffs(irq_status);
120 	return irq_linear_revmap(h, irq);
121 }
122 
123 static void hlwd_pic_irq_cascade(struct irq_desc *desc)
124 {
125 	struct irq_chip *chip = irq_desc_get_chip(desc);
126 	struct irq_domain *irq_domain = irq_desc_get_handler_data(desc);
127 	unsigned int virq;
128 
129 	raw_spin_lock(&desc->lock);
130 	chip->irq_mask(&desc->irq_data); /* IRQ_LEVEL */
131 	raw_spin_unlock(&desc->lock);
132 
133 	virq = __hlwd_pic_get_irq(irq_domain);
134 	if (virq != NO_IRQ)
135 		generic_handle_irq(virq);
136 	else
137 		pr_err("spurious interrupt!\n");
138 
139 	raw_spin_lock(&desc->lock);
140 	chip->irq_ack(&desc->irq_data); /* IRQ_LEVEL */
141 	if (!irqd_irq_disabled(&desc->irq_data) && chip->irq_unmask)
142 		chip->irq_unmask(&desc->irq_data);
143 	raw_spin_unlock(&desc->lock);
144 }
145 
146 /*
147  * Platform hooks.
148  *
149  */
150 
151 static void __hlwd_quiesce(void __iomem *io_base)
152 {
153 	/* mask and ack all IRQs */
154 	out_be32(io_base + HW_BROADWAY_IMR, 0);
155 	out_be32(io_base + HW_BROADWAY_ICR, 0xffffffff);
156 }
157 
158 struct irq_domain *hlwd_pic_init(struct device_node *np)
159 {
160 	struct irq_domain *irq_domain;
161 	struct resource res;
162 	void __iomem *io_base;
163 	int retval;
164 
165 	retval = of_address_to_resource(np, 0, &res);
166 	if (retval) {
167 		pr_err("no io memory range found\n");
168 		return NULL;
169 	}
170 	io_base = ioremap(res.start, resource_size(&res));
171 	if (!io_base) {
172 		pr_err("ioremap failed\n");
173 		return NULL;
174 	}
175 
176 	pr_info("controller at 0x%08x mapped to 0x%p\n", res.start, io_base);
177 
178 	__hlwd_quiesce(io_base);
179 
180 	irq_domain = irq_domain_add_linear(np, HLWD_NR_IRQS,
181 					   &hlwd_irq_domain_ops, io_base);
182 	if (!irq_domain) {
183 		pr_err("failed to allocate irq_domain\n");
184 		iounmap(io_base);
185 		return NULL;
186 	}
187 
188 	return irq_domain;
189 }
190 
191 unsigned int hlwd_pic_get_irq(void)
192 {
193 	return __hlwd_pic_get_irq(hlwd_irq_host);
194 }
195 
196 /*
197  * Probe function.
198  *
199  */
200 
201 void hlwd_pic_probe(void)
202 {
203 	struct irq_domain *host;
204 	struct device_node *np;
205 	const u32 *interrupts;
206 	int cascade_virq;
207 
208 	for_each_compatible_node(np, NULL, "nintendo,hollywood-pic") {
209 		interrupts = of_get_property(np, "interrupts", NULL);
210 		if (interrupts) {
211 			host = hlwd_pic_init(np);
212 			BUG_ON(!host);
213 			cascade_virq = irq_of_parse_and_map(np, 0);
214 			irq_set_handler_data(cascade_virq, host);
215 			irq_set_chained_handler(cascade_virq,
216 						hlwd_pic_irq_cascade);
217 			hlwd_irq_host = host;
218 			break;
219 		}
220 	}
221 }
222 
223 /**
224  * hlwd_quiesce() - quiesce hollywood irq controller
225  *
226  * Mask and ack all interrupt sources.
227  *
228  */
229 void hlwd_quiesce(void)
230 {
231 	void __iomem *io_base = hlwd_irq_host->host_data;
232 
233 	__hlwd_quiesce(io_base);
234 }
235 
236