1 /*
2  * Synopsys DW APB ICTL irqchip driver.
3  *
4  * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
5  *
6  * based on GPL'ed 2.6 kernel sources
7  *  (c) Marvell International Ltd.
8  *
9  * This file is licensed under the terms of the GNU General Public
10  * License version 2.  This program is licensed "as is" without any
11  * warranty of any kind, whether express or implied.
12  */
13 
14 #include <linux/io.h>
15 #include <linux/irq.h>
16 #include <linux/irqchip.h>
17 #include <linux/irqchip/chained_irq.h>
18 #include <linux/of_address.h>
19 #include <linux/of_irq.h>
20 #include <linux/interrupt.h>
21 
22 #define APB_INT_ENABLE_L	0x00
23 #define APB_INT_ENABLE_H	0x04
24 #define APB_INT_MASK_L		0x08
25 #define APB_INT_MASK_H		0x0c
26 #define APB_INT_FINALSTATUS_L	0x30
27 #define APB_INT_FINALSTATUS_H	0x34
28 #define APB_INT_BASE_OFFSET	0x04
29 
30 /* irq domain of the primary interrupt controller. */
31 static struct irq_domain *dw_apb_ictl_irq_domain;
32 
33 static void __irq_entry dw_apb_ictl_handle_irq(struct pt_regs *regs)
34 {
35 	struct irq_domain *d = dw_apb_ictl_irq_domain;
36 	int n;
37 
38 	for (n = 0; n < d->revmap_size; n += 32) {
39 		struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, n);
40 		u32 stat = readl_relaxed(gc->reg_base + APB_INT_FINALSTATUS_L);
41 
42 		while (stat) {
43 			u32 hwirq = ffs(stat) - 1;
44 
45 			generic_handle_domain_irq(d, hwirq);
46 			stat &= ~BIT(hwirq);
47 		}
48 	}
49 }
50 
51 static void dw_apb_ictl_handle_irq_cascaded(struct irq_desc *desc)
52 {
53 	struct irq_domain *d = irq_desc_get_handler_data(desc);
54 	struct irq_chip *chip = irq_desc_get_chip(desc);
55 	int n;
56 
57 	chained_irq_enter(chip, desc);
58 
59 	for (n = 0; n < d->revmap_size; n += 32) {
60 		struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, n);
61 		u32 stat = readl_relaxed(gc->reg_base + APB_INT_FINALSTATUS_L);
62 
63 		while (stat) {
64 			u32 hwirq = ffs(stat) - 1;
65 			generic_handle_domain_irq(d, gc->irq_base + hwirq);
66 
67 			stat &= ~BIT(hwirq);
68 		}
69 	}
70 
71 	chained_irq_exit(chip, desc);
72 }
73 
74 static int dw_apb_ictl_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
75 				unsigned int nr_irqs, void *arg)
76 {
77 	int i, ret;
78 	irq_hw_number_t hwirq;
79 	unsigned int type = IRQ_TYPE_NONE;
80 	struct irq_fwspec *fwspec = arg;
81 
82 	ret = irq_domain_translate_onecell(domain, fwspec, &hwirq, &type);
83 	if (ret)
84 		return ret;
85 
86 	for (i = 0; i < nr_irqs; i++)
87 		irq_map_generic_chip(domain, virq + i, hwirq + i);
88 
89 	return 0;
90 }
91 
92 static const struct irq_domain_ops dw_apb_ictl_irq_domain_ops = {
93 	.translate = irq_domain_translate_onecell,
94 	.alloc = dw_apb_ictl_irq_domain_alloc,
95 	.free = irq_domain_free_irqs_top,
96 };
97 
98 #ifdef CONFIG_PM
99 static void dw_apb_ictl_resume(struct irq_data *d)
100 {
101 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
102 	struct irq_chip_type *ct = irq_data_get_chip_type(d);
103 
104 	irq_gc_lock(gc);
105 	writel_relaxed(~0, gc->reg_base + ct->regs.enable);
106 	writel_relaxed(*ct->mask_cache, gc->reg_base + ct->regs.mask);
107 	irq_gc_unlock(gc);
108 }
109 #else
110 #define dw_apb_ictl_resume	NULL
111 #endif /* CONFIG_PM */
112 
113 static int __init dw_apb_ictl_init(struct device_node *np,
114 				   struct device_node *parent)
115 {
116 	const struct irq_domain_ops *domain_ops;
117 	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
118 	struct resource r;
119 	struct irq_domain *domain;
120 	struct irq_chip_generic *gc;
121 	void __iomem *iobase;
122 	int ret, nrirqs, parent_irq, i;
123 	u32 reg;
124 
125 	if (!parent) {
126 		/* Used as the primary interrupt controller */
127 		parent_irq = 0;
128 		domain_ops = &dw_apb_ictl_irq_domain_ops;
129 	} else {
130 		/* Map the parent interrupt for the chained handler */
131 		parent_irq = irq_of_parse_and_map(np, 0);
132 		if (parent_irq <= 0) {
133 			pr_err("%pOF: unable to parse irq\n", np);
134 			return -EINVAL;
135 		}
136 		domain_ops = &irq_generic_chip_ops;
137 	}
138 
139 	ret = of_address_to_resource(np, 0, &r);
140 	if (ret) {
141 		pr_err("%pOF: unable to get resource\n", np);
142 		return ret;
143 	}
144 
145 	if (!request_mem_region(r.start, resource_size(&r), np->full_name)) {
146 		pr_err("%pOF: unable to request mem region\n", np);
147 		return -ENOMEM;
148 	}
149 
150 	iobase = ioremap(r.start, resource_size(&r));
151 	if (!iobase) {
152 		pr_err("%pOF: unable to map resource\n", np);
153 		ret = -ENOMEM;
154 		goto err_release;
155 	}
156 
157 	/*
158 	 * DW IP can be configured to allow 2-64 irqs. We can determine
159 	 * the number of irqs supported by writing into enable register
160 	 * and look for bits not set, as corresponding flip-flops will
161 	 * have been removed by synthesis tool.
162 	 */
163 
164 	/* mask and enable all interrupts */
165 	writel_relaxed(~0, iobase + APB_INT_MASK_L);
166 	writel_relaxed(~0, iobase + APB_INT_MASK_H);
167 	writel_relaxed(~0, iobase + APB_INT_ENABLE_L);
168 	writel_relaxed(~0, iobase + APB_INT_ENABLE_H);
169 
170 	reg = readl_relaxed(iobase + APB_INT_ENABLE_H);
171 	if (reg)
172 		nrirqs = 32 + fls(reg);
173 	else
174 		nrirqs = fls(readl_relaxed(iobase + APB_INT_ENABLE_L));
175 
176 	domain = irq_domain_add_linear(np, nrirqs, domain_ops, NULL);
177 	if (!domain) {
178 		pr_err("%pOF: unable to add irq domain\n", np);
179 		ret = -ENOMEM;
180 		goto err_unmap;
181 	}
182 
183 	ret = irq_alloc_domain_generic_chips(domain, 32, 1, np->name,
184 					     handle_level_irq, clr, 0,
185 					     IRQ_GC_INIT_MASK_CACHE);
186 	if (ret) {
187 		pr_err("%pOF: unable to alloc irq domain gc\n", np);
188 		goto err_unmap;
189 	}
190 
191 	for (i = 0; i < DIV_ROUND_UP(nrirqs, 32); i++) {
192 		gc = irq_get_domain_generic_chip(domain, i * 32);
193 		gc->reg_base = iobase + i * APB_INT_BASE_OFFSET;
194 		gc->chip_types[0].regs.mask = APB_INT_MASK_L;
195 		gc->chip_types[0].regs.enable = APB_INT_ENABLE_L;
196 		gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
197 		gc->chip_types[0].chip.irq_unmask = irq_gc_mask_clr_bit;
198 		gc->chip_types[0].chip.irq_resume = dw_apb_ictl_resume;
199 	}
200 
201 	if (parent_irq) {
202 		irq_set_chained_handler_and_data(parent_irq,
203 				dw_apb_ictl_handle_irq_cascaded, domain);
204 	} else {
205 		dw_apb_ictl_irq_domain = domain;
206 		set_handle_irq(dw_apb_ictl_handle_irq);
207 	}
208 
209 	return 0;
210 
211 err_unmap:
212 	iounmap(iobase);
213 err_release:
214 	release_mem_region(r.start, resource_size(&r));
215 	return ret;
216 }
217 IRQCHIP_DECLARE(dw_apb_ictl,
218 		"snps,dw-apb-ictl", dw_apb_ictl_init);
219