1 /*
2  * Texas Instruments Keystone IRQ controller IP driver
3  *
4  * Copyright (C) 2014 Texas Instruments, Inc.
5  * Author: Sajesh Kumar Saran <sajesh@ti.com>
6  *	   Grygorii Strashko <grygorii.strashko@ti.com>
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 as
10  * published by the Free Software Foundation version 2.
11  *
12  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
13  * kind, whether express or implied; without even the implied warranty
14  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  */
17 
18 #include <linux/irq.h>
19 #include <linux/bitops.h>
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/irqdomain.h>
23 #include <linux/irqchip.h>
24 #include <linux/irqchip/chained_irq.h>
25 #include <linux/of.h>
26 #include <linux/of_platform.h>
27 #include <linux/mfd/syscon.h>
28 #include <linux/regmap.h>
29 
30 /* The source ID bits start from 4 to 31 (total 28 bits)*/
31 #define BIT_OFS			4
32 #define KEYSTONE_N_IRQ		(32 - BIT_OFS)
33 
34 struct keystone_irq_device {
35 	struct device		*dev;
36 	struct irq_chip		 chip;
37 	u32			 mask;
38 	int			 irq;
39 	struct irq_domain	*irqd;
40 	struct regmap		*devctrl_regs;
41 	u32			devctrl_offset;
42 };
43 
44 static inline u32 keystone_irq_readl(struct keystone_irq_device *kirq)
45 {
46 	int ret;
47 	u32 val = 0;
48 
49 	ret = regmap_read(kirq->devctrl_regs, kirq->devctrl_offset, &val);
50 	if (ret < 0)
51 		dev_dbg(kirq->dev, "irq read failed ret(%d)\n", ret);
52 	return val;
53 }
54 
55 static inline void
56 keystone_irq_writel(struct keystone_irq_device *kirq, u32 value)
57 {
58 	int ret;
59 
60 	ret = regmap_write(kirq->devctrl_regs, kirq->devctrl_offset, value);
61 	if (ret < 0)
62 		dev_dbg(kirq->dev, "irq write failed ret(%d)\n", ret);
63 }
64 
65 static void keystone_irq_setmask(struct irq_data *d)
66 {
67 	struct keystone_irq_device *kirq = irq_data_get_irq_chip_data(d);
68 
69 	kirq->mask |= BIT(d->hwirq);
70 	dev_dbg(kirq->dev, "mask %lu [%x]\n", d->hwirq, kirq->mask);
71 }
72 
73 static void keystone_irq_unmask(struct irq_data *d)
74 {
75 	struct keystone_irq_device *kirq = irq_data_get_irq_chip_data(d);
76 
77 	kirq->mask &= ~BIT(d->hwirq);
78 	dev_dbg(kirq->dev, "unmask %lu [%x]\n", d->hwirq, kirq->mask);
79 }
80 
81 static void keystone_irq_ack(struct irq_data *d)
82 {
83 	/* nothing to do here */
84 }
85 
86 static void keystone_irq_handler(struct irq_desc *desc)
87 {
88 	unsigned int irq = irq_desc_get_irq(desc);
89 	struct keystone_irq_device *kirq = irq_desc_get_handler_data(desc);
90 	unsigned long pending;
91 	int src, virq;
92 
93 	dev_dbg(kirq->dev, "start irq %d\n", irq);
94 
95 	chained_irq_enter(irq_desc_get_chip(desc), desc);
96 
97 	pending = keystone_irq_readl(kirq);
98 	keystone_irq_writel(kirq, pending);
99 
100 	dev_dbg(kirq->dev, "pending 0x%lx, mask 0x%x\n", pending, kirq->mask);
101 
102 	pending = (pending >> BIT_OFS) & ~kirq->mask;
103 
104 	dev_dbg(kirq->dev, "pending after mask 0x%lx\n", pending);
105 
106 	for (src = 0; src < KEYSTONE_N_IRQ; src++) {
107 		if (BIT(src) & pending) {
108 			virq = irq_find_mapping(kirq->irqd, src);
109 			dev_dbg(kirq->dev, "dispatch bit %d, virq %d\n",
110 				src, virq);
111 			if (!virq)
112 				dev_warn(kirq->dev, "sporious irq detected hwirq %d, virq %d\n",
113 					 src, virq);
114 			generic_handle_irq(virq);
115 		}
116 	}
117 
118 	chained_irq_exit(irq_desc_get_chip(desc), desc);
119 
120 	dev_dbg(kirq->dev, "end irq %d\n", irq);
121 }
122 
123 static int keystone_irq_map(struct irq_domain *h, unsigned int virq,
124 				irq_hw_number_t hw)
125 {
126 	struct keystone_irq_device *kirq = h->host_data;
127 
128 	irq_set_chip_data(virq, kirq);
129 	irq_set_chip_and_handler(virq, &kirq->chip, handle_level_irq);
130 	irq_set_probe(virq);
131 	return 0;
132 }
133 
134 static const struct irq_domain_ops keystone_irq_ops = {
135 	.map	= keystone_irq_map,
136 	.xlate	= irq_domain_xlate_onecell,
137 };
138 
139 static int keystone_irq_probe(struct platform_device *pdev)
140 {
141 	struct device *dev = &pdev->dev;
142 	struct device_node *np = dev->of_node;
143 	struct keystone_irq_device *kirq;
144 	int ret;
145 
146 	if (np == NULL)
147 		return -EINVAL;
148 
149 	kirq = devm_kzalloc(dev, sizeof(*kirq), GFP_KERNEL);
150 	if (!kirq)
151 		return -ENOMEM;
152 
153 	kirq->devctrl_regs =
154 		syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev");
155 	if (IS_ERR(kirq->devctrl_regs))
156 		return PTR_ERR(kirq->devctrl_regs);
157 
158 	ret = of_property_read_u32_index(np, "ti,syscon-dev", 1,
159 					 &kirq->devctrl_offset);
160 	if (ret) {
161 		dev_err(dev, "couldn't read the devctrl_offset offset!\n");
162 		return ret;
163 	}
164 
165 	kirq->irq = platform_get_irq(pdev, 0);
166 	if (kirq->irq < 0) {
167 		dev_err(dev, "no irq resource %d\n", kirq->irq);
168 		return kirq->irq;
169 	}
170 
171 	kirq->dev = dev;
172 	kirq->mask = ~0x0;
173 	kirq->chip.name		= "keystone-irq";
174 	kirq->chip.irq_ack	= keystone_irq_ack;
175 	kirq->chip.irq_mask	= keystone_irq_setmask;
176 	kirq->chip.irq_unmask	= keystone_irq_unmask;
177 
178 	kirq->irqd = irq_domain_add_linear(np, KEYSTONE_N_IRQ,
179 					   &keystone_irq_ops, kirq);
180 	if (!kirq->irqd) {
181 		dev_err(dev, "IRQ domain registration failed\n");
182 		return -ENODEV;
183 	}
184 
185 	platform_set_drvdata(pdev, kirq);
186 
187 	irq_set_chained_handler_and_data(kirq->irq, keystone_irq_handler, kirq);
188 
189 	/* clear all source bits */
190 	keystone_irq_writel(kirq, ~0x0);
191 
192 	dev_info(dev, "irqchip registered, nr_irqs %u\n", KEYSTONE_N_IRQ);
193 
194 	return 0;
195 }
196 
197 static int keystone_irq_remove(struct platform_device *pdev)
198 {
199 	struct keystone_irq_device *kirq = platform_get_drvdata(pdev);
200 	int hwirq;
201 
202 	for (hwirq = 0; hwirq < KEYSTONE_N_IRQ; hwirq++)
203 		irq_dispose_mapping(irq_find_mapping(kirq->irqd, hwirq));
204 
205 	irq_domain_remove(kirq->irqd);
206 	return 0;
207 }
208 
209 static const struct of_device_id keystone_irq_dt_ids[] = {
210 	{ .compatible = "ti,keystone-irq", },
211 	{},
212 };
213 MODULE_DEVICE_TABLE(of, keystone_irq_dt_ids);
214 
215 static struct platform_driver keystone_irq_device_driver = {
216 	.probe		= keystone_irq_probe,
217 	.remove		= keystone_irq_remove,
218 	.driver		= {
219 		.name	= "keystone_irq",
220 		.of_match_table	= of_match_ptr(keystone_irq_dt_ids),
221 	}
222 };
223 
224 module_platform_driver(keystone_irq_device_driver);
225 
226 MODULE_AUTHOR("Texas Instruments");
227 MODULE_AUTHOR("Sajesh Kumar Saran");
228 MODULE_AUTHOR("Grygorii Strashko");
229 MODULE_DESCRIPTION("Keystone IRQ chip");
230 MODULE_LICENSE("GPL v2");
231