1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2001 MontaVista Software Inc.
4 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
5 *
6 * Copyright (C) 2001 Ralf Baechle
7 * Copyright (C) 2005  MIPS Technologies, Inc.	All rights reserved.
8 *	Author: Maciej W. Rozycki <macro@mips.com>
9 *
10 * This file define the irq handler for MIPS CPU interrupts.
11 */
12
13/*
14 * Almost all MIPS CPUs define 8 interrupt sources.  They are typically
15 * level triggered (i.e., cannot be cleared from CPU; must be cleared from
16 * device).
17 *
18 * The first two are software interrupts (i.e. not exposed as pins) which
19 * may be used for IPIs in multi-threaded single-core systems.
20 *
21 * The last one is usually the CPU timer interrupt if the counter register
22 * is present, or for old CPUs with an external FPU by convention it's the
23 * FPU exception interrupt.
24 */
25#include <linux/init.h>
26#include <linux/interrupt.h>
27#include <linux/kernel.h>
28#include <linux/irq.h>
29#include <linux/irqchip.h>
30#include <linux/irqdomain.h>
31
32#include <asm/irq_cpu.h>
33#include <asm/mipsregs.h>
34#include <asm/mipsmtregs.h>
35#include <asm/setup.h>
36
37static struct irq_domain *irq_domain;
38static struct irq_domain *ipi_domain;
39
40static inline void unmask_mips_irq(struct irq_data *d)
41{
42	set_c0_status(IE_SW0 << d->hwirq);
43	irq_enable_hazard();
44}
45
46static inline void mask_mips_irq(struct irq_data *d)
47{
48	clear_c0_status(IE_SW0 << d->hwirq);
49	irq_disable_hazard();
50}
51
52static struct irq_chip mips_cpu_irq_controller = {
53	.name		= "MIPS",
54	.irq_ack	= mask_mips_irq,
55	.irq_mask	= mask_mips_irq,
56	.irq_mask_ack	= mask_mips_irq,
57	.irq_unmask	= unmask_mips_irq,
58	.irq_eoi	= unmask_mips_irq,
59	.irq_disable	= mask_mips_irq,
60	.irq_enable	= unmask_mips_irq,
61};
62
63/*
64 * Basically the same as above but taking care of all the MT stuff
65 */
66
67static unsigned int mips_mt_cpu_irq_startup(struct irq_data *d)
68{
69	unsigned int vpflags = dvpe();
70
71	clear_c0_cause(C_SW0 << d->hwirq);
72	evpe(vpflags);
73	unmask_mips_irq(d);
74	return 0;
75}
76
77/*
78 * While we ack the interrupt interrupts are disabled and thus we don't need
79 * to deal with concurrency issues.  Same for mips_cpu_irq_end.
80 */
81static void mips_mt_cpu_irq_ack(struct irq_data *d)
82{
83	unsigned int vpflags = dvpe();
84	clear_c0_cause(C_SW0 << d->hwirq);
85	evpe(vpflags);
86	mask_mips_irq(d);
87}
88
89#ifdef CONFIG_GENERIC_IRQ_IPI
90
91static void mips_mt_send_ipi(struct irq_data *d, unsigned int cpu)
92{
93	irq_hw_number_t hwirq = irqd_to_hwirq(d);
94	unsigned long flags;
95	int vpflags;
96
97	local_irq_save(flags);
98
99	/* We can only send IPIs to VPEs within the local core */
100	WARN_ON(!cpus_are_siblings(smp_processor_id(), cpu));
101
102	vpflags = dvpe();
103	settc(cpu_vpe_id(&cpu_data[cpu]));
104	write_vpe_c0_cause(read_vpe_c0_cause() | (C_SW0 << hwirq));
105	evpe(vpflags);
106
107	local_irq_restore(flags);
108}
109
110#endif /* CONFIG_GENERIC_IRQ_IPI */
111
112static struct irq_chip mips_mt_cpu_irq_controller = {
113	.name		= "MIPS",
114	.irq_startup	= mips_mt_cpu_irq_startup,
115	.irq_ack	= mips_mt_cpu_irq_ack,
116	.irq_mask	= mask_mips_irq,
117	.irq_mask_ack	= mips_mt_cpu_irq_ack,
118	.irq_unmask	= unmask_mips_irq,
119	.irq_eoi	= unmask_mips_irq,
120	.irq_disable	= mask_mips_irq,
121	.irq_enable	= unmask_mips_irq,
122#ifdef CONFIG_GENERIC_IRQ_IPI
123	.ipi_send_single = mips_mt_send_ipi,
124#endif
125};
126
127asmlinkage void __weak plat_irq_dispatch(void)
128{
129	unsigned long pending = read_c0_cause() & read_c0_status() & ST0_IM;
130	int irq;
131
132	if (!pending) {
133		spurious_interrupt();
134		return;
135	}
136
137	pending >>= CAUSEB_IP;
138	while (pending) {
139		struct irq_domain *d;
140
141		irq = fls(pending) - 1;
142		if (IS_ENABLED(CONFIG_GENERIC_IRQ_IPI) && irq < 2)
143			d = ipi_domain;
144		else
145			d = irq_domain;
146
147		do_domain_IRQ(d, irq);
148		pending &= ~BIT(irq);
149	}
150}
151
152static int mips_cpu_intc_map(struct irq_domain *d, unsigned int irq,
153			     irq_hw_number_t hw)
154{
155	struct irq_chip *chip;
156
157	if (hw < 2 && cpu_has_mipsmt) {
158		/* Software interrupts are used for MT/CMT IPI */
159		chip = &mips_mt_cpu_irq_controller;
160	} else {
161		chip = &mips_cpu_irq_controller;
162	}
163
164	if (cpu_has_vint)
165		set_vi_handler(hw, plat_irq_dispatch);
166
167	irq_set_chip_and_handler(irq, chip, handle_percpu_irq);
168
169	return 0;
170}
171
172static const struct irq_domain_ops mips_cpu_intc_irq_domain_ops = {
173	.map = mips_cpu_intc_map,
174	.xlate = irq_domain_xlate_onecell,
175};
176
177#ifdef CONFIG_GENERIC_IRQ_IPI
178
179struct cpu_ipi_domain_state {
180	DECLARE_BITMAP(allocated, 2);
181};
182
183static int mips_cpu_ipi_alloc(struct irq_domain *domain, unsigned int virq,
184			      unsigned int nr_irqs, void *arg)
185{
186	struct cpu_ipi_domain_state *state = domain->host_data;
187	unsigned int i, hwirq;
188	int ret;
189
190	for (i = 0; i < nr_irqs; i++) {
191		hwirq = find_first_zero_bit(state->allocated, 2);
192		if (hwirq == 2)
193			return -EBUSY;
194		bitmap_set(state->allocated, hwirq, 1);
195
196		ret = irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq,
197						    &mips_mt_cpu_irq_controller,
198						    NULL);
199		if (ret)
200			return ret;
201
202		ret = irq_domain_set_hwirq_and_chip(domain->parent, virq + i, hwirq,
203						    &mips_mt_cpu_irq_controller,
204						    NULL);
205
206		if (ret)
207			return ret;
208
209		ret = irq_set_irq_type(virq + i, IRQ_TYPE_LEVEL_HIGH);
210		if (ret)
211			return ret;
212	}
213
214	return 0;
215}
216
217static int mips_cpu_ipi_match(struct irq_domain *d, struct device_node *node,
218			      enum irq_domain_bus_token bus_token)
219{
220	bool is_ipi;
221
222	switch (bus_token) {
223	case DOMAIN_BUS_IPI:
224		is_ipi = d->bus_token == bus_token;
225		return (!node || (to_of_node(d->fwnode) == node)) && is_ipi;
226	default:
227		return 0;
228	}
229}
230
231static const struct irq_domain_ops mips_cpu_ipi_chip_ops = {
232	.alloc	= mips_cpu_ipi_alloc,
233	.match	= mips_cpu_ipi_match,
234};
235
236static void mips_cpu_register_ipi_domain(struct device_node *of_node)
237{
238	struct cpu_ipi_domain_state *ipi_domain_state;
239
240	ipi_domain_state = kzalloc(sizeof(*ipi_domain_state), GFP_KERNEL);
241	ipi_domain = irq_domain_add_hierarchy(irq_domain,
242					      IRQ_DOMAIN_FLAG_IPI_SINGLE,
243					      2, of_node,
244					      &mips_cpu_ipi_chip_ops,
245					      ipi_domain_state);
246	if (!ipi_domain)
247		panic("Failed to add MIPS CPU IPI domain");
248	irq_domain_update_bus_token(ipi_domain, DOMAIN_BUS_IPI);
249}
250
251#else /* !CONFIG_GENERIC_IRQ_IPI */
252
253static inline void mips_cpu_register_ipi_domain(struct device_node *of_node) {}
254
255#endif /* !CONFIG_GENERIC_IRQ_IPI */
256
257static void __init __mips_cpu_irq_init(struct device_node *of_node)
258{
259	/* Mask interrupts. */
260	clear_c0_status(ST0_IM);
261	clear_c0_cause(CAUSEF_IP);
262
263	irq_domain = irq_domain_add_legacy(of_node, 8, MIPS_CPU_IRQ_BASE, 0,
264					   &mips_cpu_intc_irq_domain_ops,
265					   NULL);
266	if (!irq_domain)
267		panic("Failed to add irqdomain for MIPS CPU");
268
269	/*
270	 * Only proceed to register the software interrupt IPI implementation
271	 * for CPUs which implement the MIPS MT (multi-threading) ASE.
272	 */
273	if (cpu_has_mipsmt)
274		mips_cpu_register_ipi_domain(of_node);
275}
276
277void __init mips_cpu_irq_init(void)
278{
279	__mips_cpu_irq_init(NULL);
280}
281
282int __init mips_cpu_irq_of_init(struct device_node *of_node,
283				struct device_node *parent)
284{
285	__mips_cpu_irq_init(of_node);
286	return 0;
287}
288IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
289