1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
4  *  Loongson Local IO Interrupt Controller support
5  */
6 
7 #include <linux/errno.h>
8 #include <linux/init.h>
9 #include <linux/types.h>
10 #include <linux/interrupt.h>
11 #include <linux/ioport.h>
12 #include <linux/irqchip.h>
13 #include <linux/of_address.h>
14 #include <linux/of_irq.h>
15 #include <linux/io.h>
16 #include <linux/smp.h>
17 #include <linux/irqchip/chained_irq.h>
18 
19 #include <loongson.h>
20 
21 #define LIOINTC_CHIP_IRQ	32
22 #define LIOINTC_NUM_PARENT 4
23 #define LIOINTC_NUM_CORES	4
24 
25 #define LIOINTC_INTC_CHIP_START	0x20
26 
27 #define LIOINTC_REG_INTC_STATUS	(LIOINTC_INTC_CHIP_START + 0x20)
28 #define LIOINTC_REG_INTC_EN_STATUS	(LIOINTC_INTC_CHIP_START + 0x04)
29 #define LIOINTC_REG_INTC_ENABLE	(LIOINTC_INTC_CHIP_START + 0x08)
30 #define LIOINTC_REG_INTC_DISABLE	(LIOINTC_INTC_CHIP_START + 0x0c)
31 #define LIOINTC_REG_INTC_POL	(LIOINTC_INTC_CHIP_START + 0x10)
32 #define LIOINTC_REG_INTC_EDGE	(LIOINTC_INTC_CHIP_START + 0x14)
33 
34 #define LIOINTC_SHIFT_INTx	4
35 
36 #define LIOINTC_ERRATA_IRQ	10
37 
38 struct liointc_handler_data {
39 	struct liointc_priv	*priv;
40 	u32			parent_int_map;
41 };
42 
43 struct liointc_priv {
44 	struct irq_chip_generic		*gc;
45 	struct liointc_handler_data	handler[LIOINTC_NUM_PARENT];
46 	void __iomem			*core_isr[LIOINTC_NUM_CORES];
47 	u8				map_cache[LIOINTC_CHIP_IRQ];
48 	bool				has_lpc_irq_errata;
49 };
50 
51 static void liointc_chained_handle_irq(struct irq_desc *desc)
52 {
53 	struct liointc_handler_data *handler = irq_desc_get_handler_data(desc);
54 	struct irq_chip *chip = irq_desc_get_chip(desc);
55 	struct irq_chip_generic *gc = handler->priv->gc;
56 	int core = get_ebase_cpunum() % LIOINTC_NUM_CORES;
57 	u32 pending;
58 
59 	chained_irq_enter(chip, desc);
60 
61 	pending = readl(handler->priv->core_isr[core]);
62 
63 	if (!pending) {
64 		/* Always blame LPC IRQ if we have that bug */
65 		if (handler->priv->has_lpc_irq_errata &&
66 			(handler->parent_int_map & gc->mask_cache &
67 			BIT(LIOINTC_ERRATA_IRQ)))
68 			pending = BIT(LIOINTC_ERRATA_IRQ);
69 		else
70 			spurious_interrupt();
71 	}
72 
73 	while (pending) {
74 		int bit = __ffs(pending);
75 
76 		generic_handle_irq(irq_find_mapping(gc->domain, bit));
77 		pending &= ~BIT(bit);
78 	}
79 
80 	chained_irq_exit(chip, desc);
81 }
82 
83 static void liointc_set_bit(struct irq_chip_generic *gc,
84 				unsigned int offset,
85 				u32 mask, bool set)
86 {
87 	if (set)
88 		writel(readl(gc->reg_base + offset) | mask,
89 				gc->reg_base + offset);
90 	else
91 		writel(readl(gc->reg_base + offset) & ~mask,
92 				gc->reg_base + offset);
93 }
94 
95 static int liointc_set_type(struct irq_data *data, unsigned int type)
96 {
97 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
98 	u32 mask = data->mask;
99 	unsigned long flags;
100 
101 	irq_gc_lock_irqsave(gc, flags);
102 	switch (type) {
103 	case IRQ_TYPE_LEVEL_HIGH:
104 		liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, false);
105 		liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, true);
106 		break;
107 	case IRQ_TYPE_LEVEL_LOW:
108 		liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, false);
109 		liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, false);
110 		break;
111 	case IRQ_TYPE_EDGE_RISING:
112 		liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, true);
113 		liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, true);
114 		break;
115 	case IRQ_TYPE_EDGE_FALLING:
116 		liointc_set_bit(gc, LIOINTC_REG_INTC_EDGE, mask, true);
117 		liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, false);
118 		break;
119 	default:
120 		irq_gc_unlock_irqrestore(gc, flags);
121 		return -EINVAL;
122 	}
123 	irq_gc_unlock_irqrestore(gc, flags);
124 
125 	irqd_set_trigger_type(data, type);
126 	return 0;
127 }
128 
129 static void liointc_resume(struct irq_chip_generic *gc)
130 {
131 	struct liointc_priv *priv = gc->private;
132 	unsigned long flags;
133 	int i;
134 
135 	irq_gc_lock_irqsave(gc, flags);
136 	/* Disable all at first */
137 	writel(0xffffffff, gc->reg_base + LIOINTC_REG_INTC_DISABLE);
138 	/* Restore map cache */
139 	for (i = 0; i < LIOINTC_CHIP_IRQ; i++)
140 		writeb(priv->map_cache[i], gc->reg_base + i);
141 	/* Restore mask cache */
142 	writel(gc->mask_cache, gc->reg_base + LIOINTC_REG_INTC_ENABLE);
143 	irq_gc_unlock_irqrestore(gc, flags);
144 }
145 
146 static const char * const parent_names[] = {"int0", "int1", "int2", "int3"};
147 static const char * const core_reg_names[] = {"isr0", "isr1", "isr2", "isr3"};
148 
149 static void __iomem *liointc_get_reg_byname(struct device_node *node,
150 						const char *name)
151 {
152 	int index = of_property_match_string(node, "reg-names", name);
153 
154 	if (index < 0)
155 		return NULL;
156 
157 	return of_iomap(node, index);
158 }
159 
160 static int __init liointc_of_init(struct device_node *node,
161 				  struct device_node *parent)
162 {
163 	struct irq_chip_generic *gc;
164 	struct irq_domain *domain;
165 	struct irq_chip_type *ct;
166 	struct liointc_priv *priv;
167 	void __iomem *base;
168 	u32 of_parent_int_map[LIOINTC_NUM_PARENT];
169 	int parent_irq[LIOINTC_NUM_PARENT];
170 	bool have_parent = FALSE;
171 	int sz, i, err = 0;
172 
173 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
174 	if (!priv)
175 		return -ENOMEM;
176 
177 	if (of_device_is_compatible(node, "loongson,liointc-2.0")) {
178 		base = liointc_get_reg_byname(node, "main");
179 		if (!base) {
180 			err = -ENODEV;
181 			goto out_free_priv;
182 		}
183 
184 		for (i = 0; i < LIOINTC_NUM_CORES; i++)
185 			priv->core_isr[i] = liointc_get_reg_byname(node, core_reg_names[i]);
186 		if (!priv->core_isr[0]) {
187 			err = -ENODEV;
188 			goto out_iounmap_base;
189 		}
190 	} else {
191 		base = of_iomap(node, 0);
192 		if (!base) {
193 			err = -ENODEV;
194 			goto out_free_priv;
195 		}
196 
197 		for (i = 0; i < LIOINTC_NUM_CORES; i++)
198 			priv->core_isr[i] = base + LIOINTC_REG_INTC_STATUS;
199 	}
200 
201 	for (i = 0; i < LIOINTC_NUM_PARENT; i++) {
202 		parent_irq[i] = of_irq_get_byname(node, parent_names[i]);
203 		if (parent_irq[i] > 0)
204 			have_parent = TRUE;
205 	}
206 	if (!have_parent) {
207 		err = -ENODEV;
208 		goto out_iounmap_isr;
209 	}
210 
211 	sz = of_property_read_variable_u32_array(node,
212 						"loongson,parent_int_map",
213 						&of_parent_int_map[0],
214 						LIOINTC_NUM_PARENT,
215 						LIOINTC_NUM_PARENT);
216 	if (sz < 4) {
217 		pr_err("loongson-liointc: No parent_int_map\n");
218 		err = -ENODEV;
219 		goto out_iounmap_isr;
220 	}
221 
222 	for (i = 0; i < LIOINTC_NUM_PARENT; i++)
223 		priv->handler[i].parent_int_map = of_parent_int_map[i];
224 
225 	/* Setup IRQ domain */
226 	domain = irq_domain_add_linear(node, 32,
227 					&irq_generic_chip_ops, priv);
228 	if (!domain) {
229 		pr_err("loongson-liointc: cannot add IRQ domain\n");
230 		err = -EINVAL;
231 		goto out_iounmap_isr;
232 	}
233 
234 	err = irq_alloc_domain_generic_chips(domain, 32, 1,
235 					node->full_name, handle_level_irq,
236 					IRQ_NOPROBE, 0, 0);
237 	if (err) {
238 		pr_err("loongson-liointc: unable to register IRQ domain\n");
239 		goto out_free_domain;
240 	}
241 
242 
243 	/* Disable all IRQs */
244 	writel(0xffffffff, base + LIOINTC_REG_INTC_DISABLE);
245 	/* Set to level triggered */
246 	writel(0x0, base + LIOINTC_REG_INTC_EDGE);
247 
248 	/* Generate parent INT part of map cache */
249 	for (i = 0; i < LIOINTC_NUM_PARENT; i++) {
250 		u32 pending = priv->handler[i].parent_int_map;
251 
252 		while (pending) {
253 			int bit = __ffs(pending);
254 
255 			priv->map_cache[bit] = BIT(i) << LIOINTC_SHIFT_INTx;
256 			pending &= ~BIT(bit);
257 		}
258 	}
259 
260 	for (i = 0; i < LIOINTC_CHIP_IRQ; i++) {
261 		/* Generate core part of map cache */
262 		priv->map_cache[i] |= BIT(loongson_sysconf.boot_cpu_id);
263 		writeb(priv->map_cache[i], base + i);
264 	}
265 
266 	gc = irq_get_domain_generic_chip(domain, 0);
267 	gc->private = priv;
268 	gc->reg_base = base;
269 	gc->domain = domain;
270 	gc->resume = liointc_resume;
271 
272 	ct = gc->chip_types;
273 	ct->regs.enable = LIOINTC_REG_INTC_ENABLE;
274 	ct->regs.disable = LIOINTC_REG_INTC_DISABLE;
275 	ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
276 	ct->chip.irq_mask = irq_gc_mask_disable_reg;
277 	ct->chip.irq_mask_ack = irq_gc_mask_disable_reg;
278 	ct->chip.irq_set_type = liointc_set_type;
279 
280 	gc->mask_cache = 0;
281 	priv->gc = gc;
282 
283 	for (i = 0; i < LIOINTC_NUM_PARENT; i++) {
284 		if (parent_irq[i] <= 0)
285 			continue;
286 
287 		priv->handler[i].priv = priv;
288 		irq_set_chained_handler_and_data(parent_irq[i],
289 				liointc_chained_handle_irq, &priv->handler[i]);
290 	}
291 
292 	return 0;
293 
294 out_free_domain:
295 	irq_domain_remove(domain);
296 out_iounmap_isr:
297 	for (i = 0; i < LIOINTC_NUM_CORES; i++) {
298 		if (!priv->core_isr[i])
299 			continue;
300 		iounmap(priv->core_isr[i]);
301 	}
302 out_iounmap_base:
303 	iounmap(base);
304 out_free_priv:
305 	kfree(priv);
306 
307 	return err;
308 }
309 
310 IRQCHIP_DECLARE(loongson_liointc_1_0, "loongson,liointc-1.0", liointc_of_init);
311 IRQCHIP_DECLARE(loongson_liointc_1_0a, "loongson,liointc-1.0a", liointc_of_init);
312 IRQCHIP_DECLARE(loongson_liointc_2_0, "loongson,liointc-2.0", liointc_of_init);
313