1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Broadcom BCM6345 style Level 1 interrupt controller driver
4  *
5  * Copyright (C) 2014 Broadcom Corporation
6  * Copyright 2015 Simon Arlott
7  *
8  * This is based on the BCM7038 (which supports SMP) but with a single
9  * enable register instead of separate mask/set/clear registers.
10  *
11  * The BCM3380 has a similar mask/status register layout, but each pair
12  * of words is at separate locations (and SMP is not supported).
13  *
14  * ENABLE/STATUS words are packed next to each other for each CPU:
15  *
16  * BCM6368:
17  *   0x1000_0020: CPU0_W0_ENABLE
18  *   0x1000_0024: CPU0_W1_ENABLE
19  *   0x1000_0028: CPU0_W0_STATUS		IRQs 31-63
20  *   0x1000_002c: CPU0_W1_STATUS		IRQs 0-31
21  *   0x1000_0030: CPU1_W0_ENABLE
22  *   0x1000_0034: CPU1_W1_ENABLE
23  *   0x1000_0038: CPU1_W0_STATUS		IRQs 31-63
24  *   0x1000_003c: CPU1_W1_STATUS		IRQs 0-31
25  *
26  * BCM63168:
27  *   0x1000_0020: CPU0_W0_ENABLE
28  *   0x1000_0024: CPU0_W1_ENABLE
29  *   0x1000_0028: CPU0_W2_ENABLE
30  *   0x1000_002c: CPU0_W3_ENABLE
31  *   0x1000_0030: CPU0_W0_STATUS	IRQs 96-127
32  *   0x1000_0034: CPU0_W1_STATUS	IRQs 64-95
33  *   0x1000_0038: CPU0_W2_STATUS	IRQs 32-63
34  *   0x1000_003c: CPU0_W3_STATUS	IRQs 0-31
35  *   0x1000_0040: CPU1_W0_ENABLE
36  *   0x1000_0044: CPU1_W1_ENABLE
37  *   0x1000_0048: CPU1_W2_ENABLE
38  *   0x1000_004c: CPU1_W3_ENABLE
39  *   0x1000_0050: CPU1_W0_STATUS	IRQs 96-127
40  *   0x1000_0054: CPU1_W1_STATUS	IRQs 64-95
41  *   0x1000_0058: CPU1_W2_STATUS	IRQs 32-63
42  *   0x1000_005c: CPU1_W3_STATUS	IRQs 0-31
43  *
44  * IRQs are numbered in CPU native endian order
45  * (which is big-endian in these examples)
46  */
47 
48 #define pr_fmt(fmt)	KBUILD_MODNAME	": " fmt
49 
50 #include <linux/bitops.h>
51 #include <linux/cpumask.h>
52 #include <linux/kernel.h>
53 #include <linux/init.h>
54 #include <linux/interrupt.h>
55 #include <linux/io.h>
56 #include <linux/ioport.h>
57 #include <linux/irq.h>
58 #include <linux/irqdomain.h>
59 #include <linux/module.h>
60 #include <linux/of.h>
61 #include <linux/of_irq.h>
62 #include <linux/of_address.h>
63 #include <linux/of_platform.h>
64 #include <linux/platform_device.h>
65 #include <linux/slab.h>
66 #include <linux/smp.h>
67 #include <linux/types.h>
68 #include <linux/irqchip.h>
69 #include <linux/irqchip/chained_irq.h>
70 
71 #define IRQS_PER_WORD		32
72 #define REG_BYTES_PER_IRQ_WORD	(sizeof(u32) * 2)
73 
74 struct bcm6345_l1_cpu;
75 
76 struct bcm6345_l1_chip {
77 	raw_spinlock_t		lock;
78 	unsigned int		n_words;
79 	struct irq_domain	*domain;
80 	struct cpumask		cpumask;
81 	struct bcm6345_l1_cpu	*cpus[NR_CPUS];
82 };
83 
84 struct bcm6345_l1_cpu {
85 	void __iomem		*map_base;
86 	unsigned int		parent_irq;
87 	u32			enable_cache[];
88 };
89 
90 static inline unsigned int reg_enable(struct bcm6345_l1_chip *intc,
91 					   unsigned int word)
92 {
93 #ifdef __BIG_ENDIAN
94 	return (1 * intc->n_words - word - 1) * sizeof(u32);
95 #else
96 	return (0 * intc->n_words + word) * sizeof(u32);
97 #endif
98 }
99 
100 static inline unsigned int reg_status(struct bcm6345_l1_chip *intc,
101 				      unsigned int word)
102 {
103 #ifdef __BIG_ENDIAN
104 	return (2 * intc->n_words - word - 1) * sizeof(u32);
105 #else
106 	return (1 * intc->n_words + word) * sizeof(u32);
107 #endif
108 }
109 
110 static inline unsigned int cpu_for_irq(struct bcm6345_l1_chip *intc,
111 					struct irq_data *d)
112 {
113 	return cpumask_first_and(&intc->cpumask, irq_data_get_affinity_mask(d));
114 }
115 
116 static void bcm6345_l1_irq_handle(struct irq_desc *desc)
117 {
118 	struct bcm6345_l1_chip *intc = irq_desc_get_handler_data(desc);
119 	struct bcm6345_l1_cpu *cpu;
120 	struct irq_chip *chip = irq_desc_get_chip(desc);
121 	unsigned int idx;
122 
123 #ifdef CONFIG_SMP
124 	cpu = intc->cpus[cpu_logical_map(smp_processor_id())];
125 #else
126 	cpu = intc->cpus[0];
127 #endif
128 
129 	chained_irq_enter(chip, desc);
130 
131 	for (idx = 0; idx < intc->n_words; idx++) {
132 		int base = idx * IRQS_PER_WORD;
133 		unsigned long pending;
134 		irq_hw_number_t hwirq;
135 
136 		pending = __raw_readl(cpu->map_base + reg_status(intc, idx));
137 		pending &= __raw_readl(cpu->map_base + reg_enable(intc, idx));
138 
139 		for_each_set_bit(hwirq, &pending, IRQS_PER_WORD) {
140 			if (generic_handle_domain_irq(intc->domain, base + hwirq))
141 				spurious_interrupt();
142 		}
143 	}
144 
145 	chained_irq_exit(chip, desc);
146 }
147 
148 static inline void __bcm6345_l1_unmask(struct irq_data *d)
149 {
150 	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
151 	u32 word = d->hwirq / IRQS_PER_WORD;
152 	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
153 	unsigned int cpu_idx = cpu_for_irq(intc, d);
154 
155 	intc->cpus[cpu_idx]->enable_cache[word] |= mask;
156 	__raw_writel(intc->cpus[cpu_idx]->enable_cache[word],
157 		intc->cpus[cpu_idx]->map_base + reg_enable(intc, word));
158 }
159 
160 static inline void __bcm6345_l1_mask(struct irq_data *d)
161 {
162 	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
163 	u32 word = d->hwirq / IRQS_PER_WORD;
164 	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
165 	unsigned int cpu_idx = cpu_for_irq(intc, d);
166 
167 	intc->cpus[cpu_idx]->enable_cache[word] &= ~mask;
168 	__raw_writel(intc->cpus[cpu_idx]->enable_cache[word],
169 		intc->cpus[cpu_idx]->map_base + reg_enable(intc, word));
170 }
171 
172 static void bcm6345_l1_unmask(struct irq_data *d)
173 {
174 	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
175 	unsigned long flags;
176 
177 	raw_spin_lock_irqsave(&intc->lock, flags);
178 	__bcm6345_l1_unmask(d);
179 	raw_spin_unlock_irqrestore(&intc->lock, flags);
180 }
181 
182 static void bcm6345_l1_mask(struct irq_data *d)
183 {
184 	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
185 	unsigned long flags;
186 
187 	raw_spin_lock_irqsave(&intc->lock, flags);
188 	__bcm6345_l1_mask(d);
189 	raw_spin_unlock_irqrestore(&intc->lock, flags);
190 }
191 
192 static int bcm6345_l1_set_affinity(struct irq_data *d,
193 				   const struct cpumask *dest,
194 				   bool force)
195 {
196 	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
197 	u32 word = d->hwirq / IRQS_PER_WORD;
198 	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
199 	unsigned int old_cpu = cpu_for_irq(intc, d);
200 	unsigned int new_cpu;
201 	struct cpumask valid;
202 	unsigned long flags;
203 	bool enabled;
204 
205 	if (!cpumask_and(&valid, &intc->cpumask, dest))
206 		return -EINVAL;
207 
208 	new_cpu = cpumask_any_and(&valid, cpu_online_mask);
209 	if (new_cpu >= nr_cpu_ids)
210 		return -EINVAL;
211 
212 	dest = cpumask_of(new_cpu);
213 
214 	raw_spin_lock_irqsave(&intc->lock, flags);
215 	if (old_cpu != new_cpu) {
216 		enabled = intc->cpus[old_cpu]->enable_cache[word] & mask;
217 		if (enabled)
218 			__bcm6345_l1_mask(d);
219 		cpumask_copy(irq_data_get_affinity_mask(d), dest);
220 		if (enabled)
221 			__bcm6345_l1_unmask(d);
222 	} else {
223 		cpumask_copy(irq_data_get_affinity_mask(d), dest);
224 	}
225 	raw_spin_unlock_irqrestore(&intc->lock, flags);
226 
227 	irq_data_update_effective_affinity(d, cpumask_of(new_cpu));
228 
229 	return IRQ_SET_MASK_OK_NOCOPY;
230 }
231 
232 static int __init bcm6345_l1_init_one(struct device_node *dn,
233 				      unsigned int idx,
234 				      struct bcm6345_l1_chip *intc)
235 {
236 	struct resource res;
237 	resource_size_t sz;
238 	struct bcm6345_l1_cpu *cpu;
239 	unsigned int i, n_words;
240 
241 	if (of_address_to_resource(dn, idx, &res))
242 		return -EINVAL;
243 	sz = resource_size(&res);
244 	n_words = sz / REG_BYTES_PER_IRQ_WORD;
245 
246 	if (!intc->n_words)
247 		intc->n_words = n_words;
248 	else if (intc->n_words != n_words)
249 		return -EINVAL;
250 
251 	cpu = intc->cpus[idx] = kzalloc(sizeof(*cpu) + n_words * sizeof(u32),
252 					GFP_KERNEL);
253 	if (!cpu)
254 		return -ENOMEM;
255 
256 	cpu->map_base = ioremap(res.start, sz);
257 	if (!cpu->map_base)
258 		return -ENOMEM;
259 
260 	for (i = 0; i < n_words; i++) {
261 		cpu->enable_cache[i] = 0;
262 		__raw_writel(0, cpu->map_base + reg_enable(intc, i));
263 	}
264 
265 	cpu->parent_irq = irq_of_parse_and_map(dn, idx);
266 	if (!cpu->parent_irq) {
267 		pr_err("failed to map parent interrupt %d\n", cpu->parent_irq);
268 		return -EINVAL;
269 	}
270 	irq_set_chained_handler_and_data(cpu->parent_irq,
271 						bcm6345_l1_irq_handle, intc);
272 
273 	return 0;
274 }
275 
276 static struct irq_chip bcm6345_l1_irq_chip = {
277 	.name			= "bcm6345-l1",
278 	.irq_mask		= bcm6345_l1_mask,
279 	.irq_unmask		= bcm6345_l1_unmask,
280 	.irq_set_affinity	= bcm6345_l1_set_affinity,
281 };
282 
283 static int bcm6345_l1_map(struct irq_domain *d, unsigned int virq,
284 			  irq_hw_number_t hw_irq)
285 {
286 	irq_set_chip_and_handler(virq,
287 		&bcm6345_l1_irq_chip, handle_percpu_irq);
288 	irq_set_chip_data(virq, d->host_data);
289 	irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(virq)));
290 	return 0;
291 }
292 
293 static const struct irq_domain_ops bcm6345_l1_domain_ops = {
294 	.xlate			= irq_domain_xlate_onecell,
295 	.map			= bcm6345_l1_map,
296 };
297 
298 static int __init bcm6345_l1_of_init(struct device_node *dn,
299 			      struct device_node *parent)
300 {
301 	struct bcm6345_l1_chip *intc;
302 	unsigned int idx;
303 	int ret;
304 
305 	intc = kzalloc(sizeof(*intc), GFP_KERNEL);
306 	if (!intc)
307 		return -ENOMEM;
308 
309 	for_each_possible_cpu(idx) {
310 		ret = bcm6345_l1_init_one(dn, idx, intc);
311 		if (ret)
312 			pr_err("failed to init intc L1 for cpu %d: %d\n",
313 				idx, ret);
314 		else
315 			cpumask_set_cpu(idx, &intc->cpumask);
316 	}
317 
318 	if (cpumask_empty(&intc->cpumask)) {
319 		ret = -ENODEV;
320 		goto out_free;
321 	}
322 
323 	raw_spin_lock_init(&intc->lock);
324 
325 	intc->domain = irq_domain_add_linear(dn, IRQS_PER_WORD * intc->n_words,
326 					     &bcm6345_l1_domain_ops,
327 					     intc);
328 	if (!intc->domain) {
329 		ret = -ENOMEM;
330 		goto out_unmap;
331 	}
332 
333 	pr_info("registered BCM6345 L1 intc (IRQs: %d)\n",
334 			IRQS_PER_WORD * intc->n_words);
335 	for_each_cpu(idx, &intc->cpumask) {
336 		struct bcm6345_l1_cpu *cpu = intc->cpus[idx];
337 
338 		pr_info("  CPU%u at MMIO 0x%p (irq = %d)\n", idx,
339 				cpu->map_base, cpu->parent_irq);
340 	}
341 
342 	return 0;
343 
344 out_unmap:
345 	for_each_possible_cpu(idx) {
346 		struct bcm6345_l1_cpu *cpu = intc->cpus[idx];
347 
348 		if (cpu) {
349 			if (cpu->map_base)
350 				iounmap(cpu->map_base);
351 			kfree(cpu);
352 		}
353 	}
354 out_free:
355 	kfree(intc);
356 	return ret;
357 }
358 
359 IRQCHIP_DECLARE(bcm6345_l1, "brcm,bcm6345-l1-intc", bcm6345_l1_of_init);
360