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 
21 #define APB_INT_ENABLE_L	0x00
22 #define APB_INT_ENABLE_H	0x04
23 #define APB_INT_MASK_L		0x08
24 #define APB_INT_MASK_H		0x0c
25 #define APB_INT_FINALSTATUS_L	0x30
26 #define APB_INT_FINALSTATUS_H	0x34
27 #define APB_INT_BASE_OFFSET	0x04
28 
29 static void dw_apb_ictl_handler(struct irq_desc *desc)
30 {
31 	struct irq_domain *d = irq_desc_get_handler_data(desc);
32 	struct irq_chip *chip = irq_desc_get_chip(desc);
33 	int n;
34 
35 	chained_irq_enter(chip, desc);
36 
37 	for (n = 0; n < d->revmap_size; n += 32) {
38 		struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, n);
39 		u32 stat = readl_relaxed(gc->reg_base + APB_INT_FINALSTATUS_L);
40 
41 		while (stat) {
42 			u32 hwirq = ffs(stat) - 1;
43 			u32 virq = irq_find_mapping(d, gc->irq_base + hwirq);
44 
45 			generic_handle_irq(virq);
46 			stat &= ~(1 << hwirq);
47 		}
48 	}
49 
50 	chained_irq_exit(chip, desc);
51 }
52 
53 #ifdef CONFIG_PM
54 static void dw_apb_ictl_resume(struct irq_data *d)
55 {
56 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
57 	struct irq_chip_type *ct = irq_data_get_chip_type(d);
58 
59 	irq_gc_lock(gc);
60 	writel_relaxed(~0, gc->reg_base + ct->regs.enable);
61 	writel_relaxed(*ct->mask_cache, gc->reg_base + ct->regs.mask);
62 	irq_gc_unlock(gc);
63 }
64 #else
65 #define dw_apb_ictl_resume	NULL
66 #endif /* CONFIG_PM */
67 
68 static int __init dw_apb_ictl_init(struct device_node *np,
69 				   struct device_node *parent)
70 {
71 	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
72 	struct resource r;
73 	struct irq_domain *domain;
74 	struct irq_chip_generic *gc;
75 	void __iomem *iobase;
76 	int ret, nrirqs, irq, i;
77 	u32 reg;
78 
79 	/* Map the parent interrupt for the chained handler */
80 	irq = irq_of_parse_and_map(np, 0);
81 	if (irq <= 0) {
82 		pr_err("%pOF: unable to parse irq\n", np);
83 		return -EINVAL;
84 	}
85 
86 	ret = of_address_to_resource(np, 0, &r);
87 	if (ret) {
88 		pr_err("%pOF: unable to get resource\n", np);
89 		return ret;
90 	}
91 
92 	if (!request_mem_region(r.start, resource_size(&r), np->full_name)) {
93 		pr_err("%pOF: unable to request mem region\n", np);
94 		return -ENOMEM;
95 	}
96 
97 	iobase = ioremap(r.start, resource_size(&r));
98 	if (!iobase) {
99 		pr_err("%pOF: unable to map resource\n", np);
100 		ret = -ENOMEM;
101 		goto err_release;
102 	}
103 
104 	/*
105 	 * DW IP can be configured to allow 2-64 irqs. We can determine
106 	 * the number of irqs supported by writing into enable register
107 	 * and look for bits not set, as corresponding flip-flops will
108 	 * have been removed by synthesis tool.
109 	 */
110 
111 	/* mask and enable all interrupts */
112 	writel_relaxed(~0, iobase + APB_INT_MASK_L);
113 	writel_relaxed(~0, iobase + APB_INT_MASK_H);
114 	writel_relaxed(~0, iobase + APB_INT_ENABLE_L);
115 	writel_relaxed(~0, iobase + APB_INT_ENABLE_H);
116 
117 	reg = readl_relaxed(iobase + APB_INT_ENABLE_H);
118 	if (reg)
119 		nrirqs = 32 + fls(reg);
120 	else
121 		nrirqs = fls(readl_relaxed(iobase + APB_INT_ENABLE_L));
122 
123 	domain = irq_domain_add_linear(np, nrirqs,
124 				       &irq_generic_chip_ops, NULL);
125 	if (!domain) {
126 		pr_err("%pOF: unable to add irq domain\n", np);
127 		ret = -ENOMEM;
128 		goto err_unmap;
129 	}
130 
131 	ret = irq_alloc_domain_generic_chips(domain, 32, 1, np->name,
132 					     handle_level_irq, clr, 0,
133 					     IRQ_GC_INIT_MASK_CACHE);
134 	if (ret) {
135 		pr_err("%pOF: unable to alloc irq domain gc\n", np);
136 		goto err_unmap;
137 	}
138 
139 	for (i = 0; i < DIV_ROUND_UP(nrirqs, 32); i++) {
140 		gc = irq_get_domain_generic_chip(domain, i * 32);
141 		gc->reg_base = iobase + i * APB_INT_BASE_OFFSET;
142 		gc->chip_types[0].regs.mask = APB_INT_MASK_L;
143 		gc->chip_types[0].regs.enable = APB_INT_ENABLE_L;
144 		gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
145 		gc->chip_types[0].chip.irq_unmask = irq_gc_mask_clr_bit;
146 		gc->chip_types[0].chip.irq_resume = dw_apb_ictl_resume;
147 	}
148 
149 	irq_set_chained_handler_and_data(irq, dw_apb_ictl_handler, domain);
150 
151 	return 0;
152 
153 err_unmap:
154 	iounmap(iobase);
155 err_release:
156 	release_mem_region(r.start, resource_size(&r));
157 	return ret;
158 }
159 IRQCHIP_DECLARE(dw_apb_ictl,
160 		"snps,dw-apb-ictl", dw_apb_ictl_init);
161