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/debugfs.h>
10 #include <linux/smp.h>
11 #include <linux/interrupt.h>
12 #include <linux/seq_file.h>
13 #include <linux/init.h>
14 #include <linux/cpu.h>
15 #include <linux/of.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 #include <linux/delay.h>
19 
20 #include <asm/prom.h>
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 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 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 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 	/* No chip data for the XICS domain */
352 	irq_domain_set_info(domain, virq, hwirq, xics_ics->chip,
353 			    NULL, 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