1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2011 IBM Corporation.
4 */
5 #include <linux/types.h>
6 #include <linux/threads.h>
7 #include <linux/kernel.h>
8 #include <linux/irq.h>
9 #include <linux/irqdomain.h>
10 #include <linux/debugfs.h>
11 #include <linux/smp.h>
12 #include <linux/interrupt.h>
13 #include <linux/seq_file.h>
14 #include <linux/init.h>
15 #include <linux/cpu.h>
16 #include <linux/of.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19 #include <linux/delay.h>
20
21 #include <asm/io.h>
22 #include <asm/smp.h>
23 #include <asm/machdep.h>
24 #include <asm/irq.h>
25 #include <asm/errno.h>
26 #include <asm/rtas.h>
27 #include <asm/xics.h>
28 #include <asm/firmware.h>
29
30 /* Globals common to all ICP/ICS implementations */
31 const struct icp_ops *icp_ops;
32
33 unsigned int xics_default_server = 0xff;
34 unsigned int xics_default_distrib_server = 0;
35 unsigned int xics_interrupt_server_size = 8;
36
37 DEFINE_PER_CPU(struct xics_cppr, xics_cppr);
38
39 struct irq_domain *xics_host;
40
41 static struct ics *xics_ics;
42
43 void xics_update_irq_servers(void)
44 {
45 int i, j;
46 struct device_node *np;
47 u32 ilen;
48 const __be32 *ireg;
49 u32 hcpuid;
50
51 /* Find the server numbers for the boot cpu. */
52 np = of_get_cpu_node(boot_cpuid, NULL);
53 BUG_ON(!np);
54
55 hcpuid = get_hard_smp_processor_id(boot_cpuid);
56 xics_default_server = xics_default_distrib_server = hcpuid;
57
58 pr_devel("xics: xics_default_server = 0x%x\n", xics_default_server);
59
60 ireg = of_get_property(np, "ibm,ppc-interrupt-gserver#s", &ilen);
61 if (!ireg) {
62 of_node_put(np);
63 return;
64 }
65
66 i = ilen / sizeof(int);
67
68 /* Global interrupt distribution server is specified in the last
69 * entry of "ibm,ppc-interrupt-gserver#s" property. Get the last
70 * entry fom this property for current boot cpu id and use it as
71 * default distribution server
72 */
73 for (j = 0; j < i; j += 2) {
74 if (be32_to_cpu(ireg[j]) == hcpuid) {
75 xics_default_distrib_server = be32_to_cpu(ireg[j+1]);
76 break;
77 }
78 }
79 pr_devel("xics: xics_default_distrib_server = 0x%x\n",
80 xics_default_distrib_server);
81 of_node_put(np);
82 }
83
84 /* GIQ stuff, currently only supported on RTAS setups, will have
85 * to be sorted properly for bare metal
86 */
87 void xics_set_cpu_giq(unsigned int gserver, unsigned int join)
88 {
89 #ifdef CONFIG_PPC_RTAS
90 int index;
91 int status;
92
93 if (!rtas_indicator_present(GLOBAL_INTERRUPT_QUEUE, NULL))
94 return;
95
96 index = (1UL << xics_interrupt_server_size) - 1 - gserver;
97
98 status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE, index, join);
99
100 WARN(status < 0, "set-indicator(%d, %d, %u) returned %d\n",
101 GLOBAL_INTERRUPT_QUEUE, index, join, status);
102 #endif
103 }
104
105 void xics_setup_cpu(void)
106 {
107 icp_ops->set_priority(LOWEST_PRIORITY);
108
109 xics_set_cpu_giq(xics_default_distrib_server, 1);
110 }
111
112 void xics_mask_unknown_vec(unsigned int vec)
113 {
114 pr_err("Interrupt 0x%x (real) is invalid, disabling it.\n", vec);
115
116 if (WARN_ON(!xics_ics))
117 return;
118 xics_ics->mask_unknown(xics_ics, vec);
119 }
120
121
122 #ifdef CONFIG_SMP
123
124 static void __init xics_request_ipi(void)
125 {
126 unsigned int ipi;
127
128 ipi = irq_create_mapping(xics_host, XICS_IPI);
129 BUG_ON(!ipi);
130
131 /*
132 * IPIs are marked IRQF_PERCPU. The handler was set in map.
133 */
134 BUG_ON(request_irq(ipi, icp_ops->ipi_action,
135 IRQF_NO_DEBUG | IRQF_PERCPU | IRQF_NO_THREAD, "IPI", NULL));
136 }
137
138 void __init xics_smp_probe(void)
139 {
140 /* Register all the IPIs */
141 xics_request_ipi();
142
143 /* Setup cause_ipi callback based on which ICP is used */
144 smp_ops->cause_ipi = icp_ops->cause_ipi;
145 }
146
147 #endif /* CONFIG_SMP */
148
149 noinstr void xics_teardown_cpu(void)
150 {
151 struct xics_cppr *os_cppr = this_cpu_ptr(&xics_cppr);
152
153 /*
154 * we have to reset the cppr index to 0 because we're
155 * not going to return from the IPI
156 */
157 os_cppr->index = 0;
158 icp_ops->set_priority(0);
159 icp_ops->teardown_cpu();
160 }
161
162 noinstr void xics_kexec_teardown_cpu(int secondary)
163 {
164 xics_teardown_cpu();
165
166 icp_ops->flush_ipi();
167
168 /*
169 * Some machines need to have at least one cpu in the GIQ,
170 * so leave the master cpu in the group.
171 */
172 if (secondary)
173 xics_set_cpu_giq(xics_default_distrib_server, 0);
174 }
175
176
177 #ifdef CONFIG_HOTPLUG_CPU
178
179 /* Interrupts are disabled. */
180 void xics_migrate_irqs_away(void)
181 {
182 int cpu = smp_processor_id(), hw_cpu = hard_smp_processor_id();
183 unsigned int irq, virq;
184 struct irq_desc *desc;
185
186 pr_debug("%s: CPU %u\n", __func__, cpu);
187
188 /* If we used to be the default server, move to the new "boot_cpuid" */
189 if (hw_cpu == xics_default_server)
190 xics_update_irq_servers();
191
192 /* Reject any interrupt that was queued to us... */
193 icp_ops->set_priority(0);
194
195 /* Remove ourselves from the global interrupt queue */
196 xics_set_cpu_giq(xics_default_distrib_server, 0);
197
198 for_each_irq_desc(virq, desc) {
199 struct irq_chip *chip;
200 long server;
201 unsigned long flags;
202 struct irq_data *irqd;
203
204 /* We can't set affinity on ISA interrupts */
205 if (virq < NR_IRQS_LEGACY)
206 continue;
207 /* We only need to migrate enabled IRQS */
208 if (!desc->action)
209 continue;
210 /* We need a mapping in the XICS IRQ domain */
211 irqd = irq_domain_get_irq_data(xics_host, virq);
212 if (!irqd)
213 continue;
214 irq = irqd_to_hwirq(irqd);
215 /* We need to get IPIs still. */
216 if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
217 continue;
218 chip = irq_desc_get_chip(desc);
219 if (!chip || !chip->irq_set_affinity)
220 continue;
221
222 raw_spin_lock_irqsave(&desc->lock, flags);
223
224 /* Locate interrupt server */
225 server = xics_ics->get_server(xics_ics, irq);
226 if (server < 0) {
227 pr_err("%s: Can't find server for irq %d/%x\n",
228 __func__, virq, irq);
229 goto unlock;
230 }
231
232 /* We only support delivery to all cpus or to one cpu.
233 * The irq has to be migrated only in the single cpu
234 * case.
235 */
236 if (server != hw_cpu)
237 goto unlock;
238
239 /* This is expected during cpu offline. */
240 if (cpu_online(cpu))
241 pr_warn("IRQ %u affinity broken off cpu %u\n",
242 virq, cpu);
243
244 /* Reset affinity to all cpus */
245 raw_spin_unlock_irqrestore(&desc->lock, flags);
246 irq_set_affinity(virq, cpu_all_mask);
247 continue;
248 unlock:
249 raw_spin_unlock_irqrestore(&desc->lock, flags);
250 }
251
252 /* Allow "sufficient" time to drop any inflight IRQ's */
253 mdelay(5);
254
255 /*
256 * Allow IPIs again. This is done at the very end, after migrating all
257 * interrupts, the expectation is that we'll only get woken up by an IPI
258 * interrupt beyond this point, but leave externals masked just to be
259 * safe. If we're using icp-opal this may actually allow all
260 * interrupts anyway, but that should be OK.
261 */
262 icp_ops->set_priority(DEFAULT_PRIORITY);
263
264 }
265 #endif /* CONFIG_HOTPLUG_CPU */
266
267 #ifdef CONFIG_SMP
268 /*
269 * For the moment we only implement delivery to all cpus or one cpu.
270 *
271 * If the requested affinity is cpu_all_mask, we set global affinity.
272 * If not we set it to the first cpu in the mask, even if multiple cpus
273 * are set. This is so things like irqbalance (which set core and package
274 * wide affinities) do the right thing.
275 *
276 * We need to fix this to implement support for the links
277 */
278 int xics_get_irq_server(unsigned int virq, const struct cpumask *cpumask,
279 unsigned int strict_check)
280 {
281
282 if (!distribute_irqs)
283 return xics_default_server;
284
285 if (!cpumask_subset(cpu_possible_mask, cpumask)) {
286 int server = cpumask_first_and(cpu_online_mask, cpumask);
287
288 if (server < nr_cpu_ids)
289 return get_hard_smp_processor_id(server);
290
291 if (strict_check)
292 return -1;
293 }
294
295 /*
296 * Workaround issue with some versions of JS20 firmware that
297 * deliver interrupts to cpus which haven't been started. This
298 * happens when using the maxcpus= boot option.
299 */
300 if (cpumask_equal(cpu_online_mask, cpu_present_mask))
301 return xics_default_distrib_server;
302
303 return xics_default_server;
304 }
305 #endif /* CONFIG_SMP */
306
307 static int xics_host_match(struct irq_domain *h, struct device_node *node,
308 enum irq_domain_bus_token bus_token)
309 {
310 if (WARN_ON(!xics_ics))
311 return 0;
312 return xics_ics->host_match(xics_ics, node) ? 1 : 0;
313 }
314
315 /* Dummies */
316 static void xics_ipi_unmask(struct irq_data *d) { }
317 static void xics_ipi_mask(struct irq_data *d) { }
318
319 static struct irq_chip xics_ipi_chip = {
320 .name = "XICS",
321 .irq_eoi = NULL, /* Patched at init time */
322 .irq_mask = xics_ipi_mask,
323 .irq_unmask = xics_ipi_unmask,
324 };
325
326 static int xics_host_map(struct irq_domain *domain, unsigned int virq,
327 irq_hw_number_t hwirq)
328 {
329 pr_devel("xics: map virq %d, hwirq 0x%lx\n", virq, hwirq);
330
331 /*
332 * Mark interrupts as edge sensitive by default so that resend
333 * actually works. The device-tree parsing will turn the LSIs
334 * back to level.
335 */
336 irq_clear_status_flags(virq, IRQ_LEVEL);
337
338 /* Don't call into ICS for IPIs */
339 if (hwirq == XICS_IPI) {
340 irq_set_chip_and_handler(virq, &xics_ipi_chip,
341 handle_percpu_irq);
342 return 0;
343 }
344
345 if (WARN_ON(!xics_ics))
346 return -EINVAL;
347
348 if (xics_ics->check(xics_ics, hwirq))
349 return -EINVAL;
350
351 /* Let the ICS be the chip data for the XICS domain. For ICS native */
352 irq_domain_set_info(domain, virq, hwirq, xics_ics->chip,
353 xics_ics, handle_fasteoi_irq, NULL, NULL);
354
355 return 0;
356 }
357
358 static int xics_host_xlate(struct irq_domain *h, struct device_node *ct,
359 const u32 *intspec, unsigned int intsize,
360 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
361
362 {
363 *out_hwirq = intspec[0];
364
365 /*
366 * If intsize is at least 2, we look for the type in the second cell,
367 * we assume the LSB indicates a level interrupt.
368 */
369 if (intsize > 1) {
370 if (intspec[1] & 1)
371 *out_flags = IRQ_TYPE_LEVEL_LOW;
372 else
373 *out_flags = IRQ_TYPE_EDGE_RISING;
374 } else
375 *out_flags = IRQ_TYPE_LEVEL_LOW;
376
377 return 0;
378 }
379
380 int xics_set_irq_type(struct irq_data *d, unsigned int flow_type)
381 {
382 /*
383 * We only support these. This has really no effect other than setting
384 * the corresponding descriptor bits mind you but those will in turn
385 * affect the resend function when re-enabling an edge interrupt.
386 *
387 * Set set the default to edge as explained in map().
388 */
389 if (flow_type == IRQ_TYPE_DEFAULT || flow_type == IRQ_TYPE_NONE)
390 flow_type = IRQ_TYPE_EDGE_RISING;
391
392 if (flow_type != IRQ_TYPE_EDGE_RISING &&
393 flow_type != IRQ_TYPE_LEVEL_LOW)
394 return -EINVAL;
395
396 irqd_set_trigger_type(d, flow_type);
397
398 return IRQ_SET_MASK_OK_NOCOPY;
399 }
400
401 int xics_retrigger(struct irq_data *data)
402 {
403 /*
404 * We need to push a dummy CPPR when retriggering, since the subsequent
405 * EOI will try to pop it. Passing 0 works, as the function hard codes
406 * the priority value anyway.
407 */
408 xics_push_cppr(0);
409
410 /* Tell the core to do a soft retrigger */
411 return 0;
412 }
413
414 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
415 static int xics_host_domain_translate(struct irq_domain *d, struct irq_fwspec *fwspec,
416 unsigned long *hwirq, unsigned int *type)
417 {
418 return xics_host_xlate(d, to_of_node(fwspec->fwnode), fwspec->param,
419 fwspec->param_count, hwirq, type);
420 }
421
422 static int xics_host_domain_alloc(struct irq_domain *domain, unsigned int virq,
423 unsigned int nr_irqs, void *arg)
424 {
425 struct irq_fwspec *fwspec = arg;
426 irq_hw_number_t hwirq;
427 unsigned int type = IRQ_TYPE_NONE;
428 int i, rc;
429
430 rc = xics_host_domain_translate(domain, fwspec, &hwirq, &type);
431 if (rc)
432 return rc;
433
434 pr_debug("%s %d/%lx #%d\n", __func__, virq, hwirq, nr_irqs);
435
436 for (i = 0; i < nr_irqs; i++)
437 irq_domain_set_info(domain, virq + i, hwirq + i, xics_ics->chip,
438 xics_ics, handle_fasteoi_irq, NULL, NULL);
439
440 return 0;
441 }
442
443 static void xics_host_domain_free(struct irq_domain *domain,
444 unsigned int virq, unsigned int nr_irqs)
445 {
446 pr_debug("%s %d #%d\n", __func__, virq, nr_irqs);
447 }
448 #endif
449
450 static const struct irq_domain_ops xics_host_ops = {
451 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
452 .alloc = xics_host_domain_alloc,
453 .free = xics_host_domain_free,
454 .translate = xics_host_domain_translate,
455 #endif
456 .match = xics_host_match,
457 .map = xics_host_map,
458 .xlate = xics_host_xlate,
459 };
460
461 static int __init xics_allocate_domain(void)
462 {
463 struct fwnode_handle *fn;
464
465 fn = irq_domain_alloc_named_fwnode("XICS");
466 if (!fn)
467 return -ENOMEM;
468
469 xics_host = irq_domain_create_tree(fn, &xics_host_ops, NULL);
470 if (!xics_host) {
471 irq_domain_free_fwnode(fn);
472 return -ENOMEM;
473 }
474
475 irq_set_default_host(xics_host);
476 return 0;
477 }
478
479 void __init xics_register_ics(struct ics *ics)
480 {
481 if (WARN_ONCE(xics_ics, "XICS: Source Controller is already defined !"))
482 return;
483 xics_ics = ics;
484 }
485
486 static void __init xics_get_server_size(void)
487 {
488 struct device_node *np;
489 const __be32 *isize;
490
491 /* We fetch the interrupt server size from the first ICS node
492 * we find if any
493 */
494 np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xics");
495 if (!np)
496 return;
497
498 isize = of_get_property(np, "ibm,interrupt-server#-size", NULL);
499 if (isize)
500 xics_interrupt_server_size = be32_to_cpu(*isize);
501
502 of_node_put(np);
503 }
504
505 void __init xics_init(void)
506 {
507 int rc = -1;
508
509 /* Fist locate ICP */
510 if (firmware_has_feature(FW_FEATURE_LPAR))
511 rc = icp_hv_init();
512 if (rc < 0) {
513 rc = icp_native_init();
514 if (rc == -ENODEV)
515 rc = icp_opal_init();
516 }
517 if (rc < 0) {
518 pr_warn("XICS: Cannot find a Presentation Controller !\n");
519 return;
520 }
521
522 /* Copy get_irq callback over to ppc_md */
523 ppc_md.get_irq = icp_ops->get_irq;
524
525 /* Patch up IPI chip EOI */
526 xics_ipi_chip.irq_eoi = icp_ops->eoi;
527
528 /* Now locate ICS */
529 rc = ics_rtas_init();
530 if (rc < 0)
531 rc = ics_opal_init();
532 if (rc < 0)
533 rc = ics_native_init();
534 if (rc < 0)
535 pr_warn("XICS: Cannot find a Source Controller !\n");
536
537 /* Initialize common bits */
538 xics_get_server_size();
539 xics_update_irq_servers();
540 rc = xics_allocate_domain();
541 if (rc < 0)
542 pr_err("XICS: Failed to create IRQ domain");
543 xics_setup_cpu();
544 }
545
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