1 // SPDX-License-Identifier: GPL-2.0-only
2 //
3 // Author: Steve Chen <schen@mvista.com>
4 // Copyright (C) 2008-2009, MontaVista Software, Inc. <source@mvista.com>
5 // Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
6 // Copyright (C) 2019, Texas Instruments
7 //
8 // TI Common Platform Interrupt Controller (cp_intc) driver
9 
10 #include <linux/export.h>
11 #include <linux/init.h>
12 #include <linux/irq.h>
13 #include <linux/irqchip.h>
14 #include <linux/irqchip/irq-davinci-cp-intc.h>
15 #include <linux/irqdomain.h>
16 #include <linux/io.h>
17 #include <linux/of.h>
18 #include <linux/of_address.h>
19 #include <linux/of_irq.h>
20 
21 #include <asm/exception.h>
22 
23 #define DAVINCI_CP_INTC_CTRL			0x04
24 #define DAVINCI_CP_INTC_HOST_CTRL		0x0c
25 #define DAVINCI_CP_INTC_GLOBAL_ENABLE		0x10
26 #define DAVINCI_CP_INTC_SYS_STAT_IDX_CLR	0x24
27 #define DAVINCI_CP_INTC_SYS_ENABLE_IDX_SET	0x28
28 #define DAVINCI_CP_INTC_SYS_ENABLE_IDX_CLR	0x2c
29 #define DAVINCI_CP_INTC_HOST_ENABLE_IDX_SET	0x34
30 #define DAVINCI_CP_INTC_HOST_ENABLE_IDX_CLR	0x38
31 #define DAVINCI_CP_INTC_PRIO_IDX		0x80
32 #define DAVINCI_CP_INTC_SYS_STAT_CLR(n)		(0x0280 + (n << 2))
33 #define DAVINCI_CP_INTC_SYS_ENABLE_CLR(n)	(0x0380 + (n << 2))
34 #define DAVINCI_CP_INTC_CHAN_MAP(n)		(0x0400 + (n << 2))
35 #define DAVINCI_CP_INTC_SYS_POLARITY(n)		(0x0d00 + (n << 2))
36 #define DAVINCI_CP_INTC_SYS_TYPE(n)		(0x0d80 + (n << 2))
37 #define DAVINCI_CP_INTC_HOST_ENABLE(n)		(0x1500 + (n << 2))
38 #define DAVINCI_CP_INTC_PRI_INDX_MASK		GENMASK(9, 0)
39 #define DAVINCI_CP_INTC_GPIR_NONE		BIT(31)
40 
41 static void __iomem *davinci_cp_intc_base;
42 static struct irq_domain *davinci_cp_intc_irq_domain;
43 
44 static inline unsigned int davinci_cp_intc_read(unsigned int offset)
45 {
46 	return readl_relaxed(davinci_cp_intc_base + offset);
47 }
48 
49 static inline void davinci_cp_intc_write(unsigned long value,
50 					 unsigned int offset)
51 {
52 	writel_relaxed(value, davinci_cp_intc_base + offset);
53 }
54 
55 static void davinci_cp_intc_ack_irq(struct irq_data *d)
56 {
57 	davinci_cp_intc_write(d->hwirq, DAVINCI_CP_INTC_SYS_STAT_IDX_CLR);
58 }
59 
60 static void davinci_cp_intc_mask_irq(struct irq_data *d)
61 {
62 	/* XXX don't know why we need to disable nIRQ here... */
63 	davinci_cp_intc_write(1, DAVINCI_CP_INTC_HOST_ENABLE_IDX_CLR);
64 	davinci_cp_intc_write(d->hwirq, DAVINCI_CP_INTC_SYS_ENABLE_IDX_CLR);
65 	davinci_cp_intc_write(1, DAVINCI_CP_INTC_HOST_ENABLE_IDX_SET);
66 }
67 
68 static void davinci_cp_intc_unmask_irq(struct irq_data *d)
69 {
70 	davinci_cp_intc_write(d->hwirq, DAVINCI_CP_INTC_SYS_ENABLE_IDX_SET);
71 }
72 
73 static int davinci_cp_intc_set_irq_type(struct irq_data *d,
74 					unsigned int flow_type)
75 {
76 	unsigned int reg, mask, polarity, type;
77 
78 	reg = BIT_WORD(d->hwirq);
79 	mask = BIT_MASK(d->hwirq);
80 	polarity = davinci_cp_intc_read(DAVINCI_CP_INTC_SYS_POLARITY(reg));
81 	type = davinci_cp_intc_read(DAVINCI_CP_INTC_SYS_TYPE(reg));
82 
83 	switch (flow_type) {
84 	case IRQ_TYPE_EDGE_RISING:
85 		polarity |= mask;
86 		type |= mask;
87 		break;
88 	case IRQ_TYPE_EDGE_FALLING:
89 		polarity &= ~mask;
90 		type |= mask;
91 		break;
92 	case IRQ_TYPE_LEVEL_HIGH:
93 		polarity |= mask;
94 		type &= ~mask;
95 		break;
96 	case IRQ_TYPE_LEVEL_LOW:
97 		polarity &= ~mask;
98 		type &= ~mask;
99 		break;
100 	default:
101 		return -EINVAL;
102 	}
103 
104 	davinci_cp_intc_write(polarity, DAVINCI_CP_INTC_SYS_POLARITY(reg));
105 	davinci_cp_intc_write(type, DAVINCI_CP_INTC_SYS_TYPE(reg));
106 
107 	return 0;
108 }
109 
110 static struct irq_chip davinci_cp_intc_irq_chip = {
111 	.name		= "cp_intc",
112 	.irq_ack	= davinci_cp_intc_ack_irq,
113 	.irq_mask	= davinci_cp_intc_mask_irq,
114 	.irq_unmask	= davinci_cp_intc_unmask_irq,
115 	.irq_set_type	= davinci_cp_intc_set_irq_type,
116 	.flags		= IRQCHIP_SKIP_SET_WAKE,
117 };
118 
119 static asmlinkage void __exception_irq_entry
120 davinci_cp_intc_handle_irq(struct pt_regs *regs)
121 {
122 	int gpir, irqnr, none;
123 
124 	/*
125 	 * The interrupt number is in first ten bits. The NONE field set to 1
126 	 * indicates a spurious irq.
127 	 */
128 
129 	gpir = davinci_cp_intc_read(DAVINCI_CP_INTC_PRIO_IDX);
130 	irqnr = gpir & DAVINCI_CP_INTC_PRI_INDX_MASK;
131 	none = gpir & DAVINCI_CP_INTC_GPIR_NONE;
132 
133 	if (unlikely(none)) {
134 		pr_err_once("%s: spurious irq!\n", __func__);
135 		return;
136 	}
137 
138 	generic_handle_domain_irq(davinci_cp_intc_irq_domain, irqnr);
139 }
140 
141 static int davinci_cp_intc_host_map(struct irq_domain *h, unsigned int virq,
142 			  irq_hw_number_t hw)
143 {
144 	pr_debug("cp_intc_host_map(%d, 0x%lx)\n", virq, hw);
145 
146 	irq_set_chip(virq, &davinci_cp_intc_irq_chip);
147 	irq_set_probe(virq);
148 	irq_set_handler(virq, handle_edge_irq);
149 
150 	return 0;
151 }
152 
153 static const struct irq_domain_ops davinci_cp_intc_irq_domain_ops = {
154 	.map = davinci_cp_intc_host_map,
155 	.xlate = irq_domain_xlate_onetwocell,
156 };
157 
158 static int __init
159 davinci_cp_intc_do_init(const struct davinci_cp_intc_config *config,
160 			struct device_node *node)
161 {
162 	unsigned int num_regs = BITS_TO_LONGS(config->num_irqs);
163 	int offset, irq_base;
164 	void __iomem *req;
165 
166 	req = request_mem_region(config->reg.start,
167 				 resource_size(&config->reg),
168 				 "davinci-cp-intc");
169 	if (!req) {
170 		pr_err("%s: register range busy\n", __func__);
171 		return -EBUSY;
172 	}
173 
174 	davinci_cp_intc_base = ioremap(config->reg.start,
175 				       resource_size(&config->reg));
176 	if (!davinci_cp_intc_base) {
177 		pr_err("%s: unable to ioremap register range\n", __func__);
178 		return -EINVAL;
179 	}
180 
181 	davinci_cp_intc_write(0, DAVINCI_CP_INTC_GLOBAL_ENABLE);
182 
183 	/* Disable all host interrupts */
184 	davinci_cp_intc_write(0, DAVINCI_CP_INTC_HOST_ENABLE(0));
185 
186 	/* Disable system interrupts */
187 	for (offset = 0; offset < num_regs; offset++)
188 		davinci_cp_intc_write(~0,
189 			DAVINCI_CP_INTC_SYS_ENABLE_CLR(offset));
190 
191 	/* Set to normal mode, no nesting, no priority hold */
192 	davinci_cp_intc_write(0, DAVINCI_CP_INTC_CTRL);
193 	davinci_cp_intc_write(0, DAVINCI_CP_INTC_HOST_CTRL);
194 
195 	/* Clear system interrupt status */
196 	for (offset = 0; offset < num_regs; offset++)
197 		davinci_cp_intc_write(~0,
198 			DAVINCI_CP_INTC_SYS_STAT_CLR(offset));
199 
200 	/* Enable nIRQ (what about nFIQ?) */
201 	davinci_cp_intc_write(1, DAVINCI_CP_INTC_HOST_ENABLE_IDX_SET);
202 
203 	/* Default all priorities to channel 7. */
204 	num_regs = (config->num_irqs + 3) >> 2;	/* 4 channels per register */
205 	for (offset = 0; offset < num_regs; offset++)
206 		davinci_cp_intc_write(0x07070707,
207 			DAVINCI_CP_INTC_CHAN_MAP(offset));
208 
209 	irq_base = irq_alloc_descs(-1, 0, config->num_irqs, 0);
210 	if (irq_base < 0) {
211 		pr_err("%s: unable to allocate interrupt descriptors: %d\n",
212 		       __func__, irq_base);
213 		return irq_base;
214 	}
215 
216 	davinci_cp_intc_irq_domain = irq_domain_add_legacy(
217 					node, config->num_irqs, irq_base, 0,
218 					&davinci_cp_intc_irq_domain_ops, NULL);
219 
220 	if (!davinci_cp_intc_irq_domain) {
221 		pr_err("%s: unable to create an interrupt domain\n", __func__);
222 		return -EINVAL;
223 	}
224 
225 	set_handle_irq(davinci_cp_intc_handle_irq);
226 
227 	/* Enable global interrupt */
228 	davinci_cp_intc_write(1, DAVINCI_CP_INTC_GLOBAL_ENABLE);
229 
230 	return 0;
231 }
232 
233 int __init davinci_cp_intc_init(const struct davinci_cp_intc_config *config)
234 {
235 	return davinci_cp_intc_do_init(config, NULL);
236 }
237 
238 static int __init davinci_cp_intc_of_init(struct device_node *node,
239 					  struct device_node *parent)
240 {
241 	struct davinci_cp_intc_config config = { };
242 	int ret;
243 
244 	ret = of_address_to_resource(node, 0, &config.reg);
245 	if (ret) {
246 		pr_err("%s: unable to get the register range from device-tree\n",
247 		       __func__);
248 		return ret;
249 	}
250 
251 	ret = of_property_read_u32(node, "ti,intc-size", &config.num_irqs);
252 	if (ret) {
253 		pr_err("%s: unable to read the 'ti,intc-size' property\n",
254 		       __func__);
255 		return ret;
256 	}
257 
258 	return davinci_cp_intc_do_init(&config, node);
259 }
260 IRQCHIP_DECLARE(cp_intc, "ti,cp-intc", davinci_cp_intc_of_init);
261