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
37 static struct irq_domain *irq_domain;
38 static struct irq_domain *ipi_domain;
39
unmask_mips_irq(struct irq_data * d)40 static inline void unmask_mips_irq(struct irq_data *d)
41 {
42 set_c0_status(IE_SW0 << d->hwirq);
43 irq_enable_hazard();
44 }
45
mask_mips_irq(struct irq_data * d)46 static inline void mask_mips_irq(struct irq_data *d)
47 {
48 clear_c0_status(IE_SW0 << d->hwirq);
49 irq_disable_hazard();
50 }
51
52 static 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
mips_mt_cpu_irq_startup(struct irq_data * d)67 static 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 */
mips_mt_cpu_irq_ack(struct irq_data * d)81 static 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
mips_mt_send_ipi(struct irq_data * d,unsigned int cpu)91 static 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
112 static 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
plat_irq_dispatch(void)127 asmlinkage 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
mips_cpu_intc_map(struct irq_domain * d,unsigned int irq,irq_hw_number_t hw)152 static 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
172 static 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
179 struct cpu_ipi_domain_state {
180 DECLARE_BITMAP(allocated, 2);
181 };
182
mips_cpu_ipi_alloc(struct irq_domain * domain,unsigned int virq,unsigned int nr_irqs,void * arg)183 static 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
mips_cpu_ipi_match(struct irq_domain * d,struct device_node * node,enum irq_domain_bus_token bus_token)217 static 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
231 static const struct irq_domain_ops mips_cpu_ipi_chip_ops = {
232 .alloc = mips_cpu_ipi_alloc,
233 .match = mips_cpu_ipi_match,
234 };
235
mips_cpu_register_ipi_domain(struct device_node * of_node)236 static 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
mips_cpu_register_ipi_domain(struct device_node * of_node)253 static inline void mips_cpu_register_ipi_domain(struct device_node *of_node) {}
254
255 #endif /* !CONFIG_GENERIC_IRQ_IPI */
256
__mips_cpu_irq_init(struct device_node * of_node)257 static 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
mips_cpu_irq_init(void)277 void __init mips_cpu_irq_init(void)
278 {
279 __mips_cpu_irq_init(NULL);
280 }
281
mips_cpu_irq_of_init(struct device_node * of_node,struct device_node * parent)282 int __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 }
288 IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
289