summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/sysdev/xics/xics-common.c
blob: ea5e204e345093cedfc320d06f23a804d3c8589e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
/*
 * Copyright 2011 IBM Corporation.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */
#include <linux/types.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/debugfs.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <asm/prom.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/errno.h>
#include <asm/rtas.h>
#include <asm/xics.h>
#include <asm/firmware.h>

/* Globals common to all ICP/ICS implementations */
const struct icp_ops	*icp_ops;

unsigned int xics_default_server		= 0xff;
unsigned int xics_default_distrib_server	= 0;
unsigned int xics_interrupt_server_size		= 8;

DEFINE_PER_CPU(struct xics_cppr, xics_cppr);

struct irq_domain *xics_host;

static LIST_HEAD(ics_list);

void xics_update_irq_servers(void)
{
	int i, j;
	struct device_node *np;
	u32 ilen;
	const u32 *ireg;
	u32 hcpuid;

	/* Find the server numbers for the boot cpu. */
	np = of_get_cpu_node(boot_cpuid, NULL);
	BUG_ON(!np);

	hcpuid = get_hard_smp_processor_id(boot_cpuid);
	xics_default_server = xics_default_distrib_server = hcpuid;

	pr_devel("xics: xics_default_server = 0x%x\n", xics_default_server);

	ireg = of_get_property(np, "ibm,ppc-interrupt-gserver#s", &ilen);
	if (!ireg) {
		of_node_put(np);
		return;
	}

	i = ilen / sizeof(int);

	/* Global interrupt distribution server is specified in the last
	 * entry of "ibm,ppc-interrupt-gserver#s" property. Get the last
	 * entry fom this property for current boot cpu id and use it as
	 * default distribution server
	 */
	for (j = 0; j < i; j += 2) {
		if (ireg[j] == hcpuid) {
			xics_default_distrib_server = ireg[j+1];
			break;
		}
	}
	pr_devel("xics: xics_default_distrib_server = 0x%x\n",
		 xics_default_distrib_server);
	of_node_put(np);
}

/* GIQ stuff, currently only supported on RTAS setups, will have
 * to be sorted properly for bare metal
 */
void xics_set_cpu_giq(unsigned int gserver, unsigned int join)
{
#ifdef CONFIG_PPC_RTAS
	int index;
	int status;

	if (!rtas_indicator_present(GLOBAL_INTERRUPT_QUEUE, NULL))
		return;

	index = (1UL << xics_interrupt_server_size) - 1 - gserver;

	status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE, index, join);

	WARN(status < 0, "set-indicator(%d, %d, %u) returned %d\n",
	     GLOBAL_INTERRUPT_QUEUE, index, join, status);
#endif
}

void xics_setup_cpu(void)
{
	icp_ops->set_priority(LOWEST_PRIORITY);

	xics_set_cpu_giq(xics_default_distrib_server, 1);
}

void xics_mask_unknown_vec(unsigned int vec)
{
	struct ics *ics;

	pr_err("Interrupt 0x%x (real) is invalid, disabling it.\n", vec);

	list_for_each_entry(ics, &ics_list, link)
		ics->mask_unknown(ics, vec);
}


#ifdef CONFIG_SMP

static void xics_request_ipi(void)
{
	unsigned int ipi;

	ipi = irq_create_mapping(xics_host, XICS_IPI);
	BUG_ON(ipi == NO_IRQ);

	/*
	 * IPIs are marked IRQF_PERCPU. The handler was set in map.
	 */
	BUG_ON(request_irq(ipi, icp_ops->ipi_action,
			   IRQF_PERCPU | IRQF_NO_THREAD, "IPI", NULL));
}

int __init xics_smp_probe(void)
{
	/* Setup cause_ipi callback  based on which ICP is used */
	smp_ops->cause_ipi = icp_ops->cause_ipi;

	/* Register all the IPIs */
	xics_request_ipi();

	return cpumask_weight(cpu_possible_mask);
}

#endif /* CONFIG_SMP */

void xics_teardown_cpu(void)
{
	struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);

	/*
	 * we have to reset the cppr index to 0 because we're
	 * not going to return from the IPI
	 */
	os_cppr->index = 0;
	icp_ops->set_priority(0);
	icp_ops->teardown_cpu();
}

void xics_kexec_teardown_cpu(int secondary)
{
	xics_teardown_cpu();

	icp_ops->flush_ipi();

	/*
	 * Some machines need to have at least one cpu in the GIQ,
	 * so leave the master cpu in the group.
	 */
	if (secondary)
		xics_set_cpu_giq(xics_default_distrib_server, 0);
}


#ifdef CONFIG_HOTPLUG_CPU

/* Interrupts are disabled. */
void xics_migrate_irqs_away(void)
{
	int cpu = smp_processor_id(), hw_cpu = hard_smp_processor_id();
	unsigned int irq, virq;

	/* If we used to be the default server, move to the new "boot_cpuid" */
	if (hw_cpu == xics_default_server)
		xics_update_irq_servers();

	/* Reject any interrupt that was queued to us... */
	icp_ops->set_priority(0);

	/* Remove ourselves from the global interrupt queue */
	xics_set_cpu_giq(xics_default_distrib_server, 0);

	/* Allow IPIs again... */
	icp_ops->set_priority(DEFAULT_PRIORITY);

	for_each_irq(virq) {
		struct irq_desc *desc;
		struct irq_chip *chip;
		long server;
		unsigned long flags;
		struct ics *ics;

		/* We can't set affinity on ISA interrupts */
		if (virq < NUM_ISA_INTERRUPTS)
			continue;
		desc = irq_to_desc(virq);
		/* We only need to migrate enabled IRQS */
		if (!desc || !desc->action)
			continue;
		if (desc->irq_data.domain != xics_host)
			continue;
		irq = desc->irq_data.hwirq;
		/* We need to get IPIs still. */
		if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
			continue;
		chip = irq_desc_get_chip(desc);
		if (!chip || !chip->irq_set_affinity)
			continue;

		raw_spin_lock_irqsave(&desc->lock, flags);

		/* Locate interrupt server */
		server = -1;
		ics = irq_get_chip_data(virq);
		if (ics)
			server = ics->get_server(ics, irq);
		if (server < 0) {
			printk(KERN_ERR "%s: Can't find server for irq %d\n",
			       __func__, irq);
			goto unlock;
		}

		/* We only support delivery to all cpus or to one cpu.
		 * The irq has to be migrated only in the single cpu
		 * case.
		 */
		if (server != hw_cpu)
			goto unlock;

		/* This is expected during cpu offline. */
		if (cpu_online(cpu))
			pr_warning("IRQ %u affinity broken off cpu %u\n",
			       virq, cpu);

		/* Reset affinity to all cpus */
		raw_spin_unlock_irqrestore(&desc->lock, flags);
		irq_set_affinity(virq, cpu_all_mask);
		continue;
unlock:
		raw_spin_unlock_irqrestore(&desc->lock, flags);
	}
}
#endif /* CONFIG_HOTPLUG_CPU */

#ifdef CONFIG_SMP
/*
 * For the moment we only implement delivery to all cpus or one cpu.
 *
 * If the requested affinity is cpu_all_mask, we set global affinity.
 * If not we set it to the first cpu in the mask, even if multiple cpus
 * are set. This is so things like irqbalance (which set core and package
 * wide affinities) do the right thing.
 *
 * We need to fix this to implement support for the links
 */
int xics_get_irq_server(unsigned int virq, const struct cpumask *cpumask,
			unsigned int strict_check)
{

	if (!distribute_irqs)
		return xics_default_server;

	if (!cpumask_subset(cpu_possible_mask, cpumask)) {
		int server = cpumask_first_and(cpu_online_mask, cpumask);

		if (server < nr_cpu_ids)
			return get_hard_smp_processor_id(server);

		if (strict_check)
			return -1;
	}

	/*
	 * Workaround issue with some versions of JS20 firmware that
	 * deliver interrupts to cpus which haven't been started. This
	 * happens when using the maxcpus= boot option.
	 */
	if (cpumask_equal(cpu_online_mask, cpu_present_mask))
		return xics_default_distrib_server;

	return xics_default_server;
}
#endif /* CONFIG_SMP */

static int xics_host_match(struct irq_domain *h, struct device_node *node)
{
	struct ics *ics;

	list_for_each_entry(ics, &ics_list, link)
		if (ics->host_match(ics, node))
			return 1;

	return 0;
}

/* Dummies */
static void xics_ipi_unmask(struct irq_data *d) { }
static void xics_ipi_mask(struct irq_data *d) { }

static struct irq_chip xics_ipi_chip = {
	.name = "XICS",
	.irq_eoi = NULL, /* Patched at init time */
	.irq_mask = xics_ipi_mask,
	.irq_unmask = xics_ipi_unmask,
};

static int xics_host_map(struct irq_domain *h, unsigned int virq,
			 irq_hw_number_t hw)
{
	struct ics *ics;

	pr_devel("xics: map virq %d, hwirq 0x%lx\n", virq, hw);

	/* Insert the interrupt mapping into the radix tree for fast lookup */
	irq_radix_revmap_insert(xics_host, virq, hw);

	/* They aren't all level sensitive but we just don't really know */
	irq_set_status_flags(virq, IRQ_LEVEL);

	/* Don't call into ICS for IPIs */
	if (hw == XICS_IPI) {
		irq_set_chip_and_handler(virq, &xics_ipi_chip,
					 handle_percpu_irq);
		return 0;
	}

	/* Let the ICS setup the chip data */
	list_for_each_entry(ics, &ics_list, link)
		if (ics->map(ics, virq) == 0)
			return 0;

	return -EINVAL;
}

static int xics_host_xlate(struct irq_domain *h, struct device_node *ct,
			   const u32 *intspec, unsigned int intsize,
			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)

{
	/* Current xics implementation translates everything
	 * to level. It is not technically right for MSIs but this
	 * is irrelevant at this point. We might get smarter in the future
	 */
	*out_hwirq = intspec[0];
	*out_flags = IRQ_TYPE_LEVEL_LOW;

	return 0;
}

static struct irq_domain_ops xics_host_ops = {
	.match = xics_host_match,
	.map = xics_host_map,
	.xlate = xics_host_xlate,
};

static void __init xics_init_host(void)
{
	xics_host = irq_domain_add_tree(NULL, &xics_host_ops, NULL);
	BUG_ON(xics_host == NULL);
	irq_set_default_host(xics_host);
}

void __init xics_register_ics(struct ics *ics)
{
	list_add(&ics->link, &ics_list);
}

static void __init xics_get_server_size(void)
{
	struct device_node *np;
	const u32 *isize;

	/* We fetch the interrupt server size from the first ICS node
	 * we find if any
	 */
	np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xics");
	if (!np)
		return;
	isize = of_get_property(np, "ibm,interrupt-server#-size", NULL);
	if (!isize)
		return;
	xics_interrupt_server_size = *isize;
	of_node_put(np);
}

void __init xics_init(void)
{
	int rc = -1;

	/* Fist locate ICP */
	if (firmware_has_feature(FW_FEATURE_LPAR))
		rc = icp_hv_init();
	if (rc < 0)
		rc = icp_native_init();
	if (rc < 0) {
		pr_warning("XICS: Cannot find a Presentation Controller !\n");
		return;
	}

	/* Copy get_irq callback over to ppc_md */
	ppc_md.get_irq = icp_ops->get_irq;

	/* Patch up IPI chip EOI */
	xics_ipi_chip.irq_eoi = icp_ops->eoi;

	/* Now locate ICS */
	rc = ics_rtas_init();
	if (rc < 0)
		rc = ics_opal_init();
	if (rc < 0)
		pr_warning("XICS: Cannot find a Source Controller !\n");

	/* Initialize common bits */
	xics_get_server_size();
	xics_update_irq_servers();
	xics_init_host();
	xics_setup_cpu();
}