1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2016,2017 IBM Corporation.
4 */
5
6#define pr_fmt(fmt) "xive: " fmt
7
8#include <linux/types.h>
9#include <linux/irq.h>
10#include <linux/smp.h>
11#include <linux/interrupt.h>
12#include <linux/init.h>
13#include <linux/of.h>
14#include <linux/of_address.h>
15#include <linux/of_fdt.h>
16#include <linux/slab.h>
17#include <linux/spinlock.h>
18#include <linux/bitmap.h>
19#include <linux/cpumask.h>
20#include <linux/mm.h>
21#include <linux/delay.h>
22#include <linux/libfdt.h>
23
24#include <asm/machdep.h>
25#include <asm/prom.h>
26#include <asm/io.h>
27#include <asm/smp.h>
28#include <asm/irq.h>
29#include <asm/errno.h>
30#include <asm/xive.h>
31#include <asm/xive-regs.h>
32#include <asm/hvcall.h>
33#include <asm/svm.h>
34#include <asm/ultravisor.h>
35
36#include "xive-internal.h"
37
38static u32 xive_queue_shift;
39
40struct xive_irq_bitmap {
41	unsigned long		*bitmap;
42	unsigned int		base;
43	unsigned int		count;
44	spinlock_t		lock;
45	struct list_head	list;
46};
47
48static LIST_HEAD(xive_irq_bitmaps);
49
50static int __init xive_irq_bitmap_add(int base, int count)
51{
52	struct xive_irq_bitmap *xibm;
53
54	xibm = kzalloc(sizeof(*xibm), GFP_KERNEL);
55	if (!xibm)
56		return -ENOMEM;
57
58	spin_lock_init(&xibm->lock);
59	xibm->base = base;
60	xibm->count = count;
61	xibm->bitmap = bitmap_zalloc(xibm->count, GFP_KERNEL);
62	if (!xibm->bitmap) {
63		kfree(xibm);
64		return -ENOMEM;
65	}
66	list_add(&xibm->list, &xive_irq_bitmaps);
67
68	pr_info("Using IRQ range [%x-%x]", xibm->base,
69		xibm->base + xibm->count - 1);
70	return 0;
71}
72
73static void xive_irq_bitmap_remove_all(void)
74{
75	struct xive_irq_bitmap *xibm, *tmp;
76
77	list_for_each_entry_safe(xibm, tmp, &xive_irq_bitmaps, list) {
78		list_del(&xibm->list);
79		bitmap_free(xibm->bitmap);
80		kfree(xibm);
81	}
82}
83
84static int __xive_irq_bitmap_alloc(struct xive_irq_bitmap *xibm)
85{
86	int irq;
87
88	irq = find_first_zero_bit(xibm->bitmap, xibm->count);
89	if (irq != xibm->count) {
90		set_bit(irq, xibm->bitmap);
91		irq += xibm->base;
92	} else {
93		irq = -ENOMEM;
94	}
95
96	return irq;
97}
98
99static int xive_irq_bitmap_alloc(void)
100{
101	struct xive_irq_bitmap *xibm;
102	unsigned long flags;
103	int irq = -ENOENT;
104
105	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
106		spin_lock_irqsave(&xibm->lock, flags);
107		irq = __xive_irq_bitmap_alloc(xibm);
108		spin_unlock_irqrestore(&xibm->lock, flags);
109		if (irq >= 0)
110			break;
111	}
112	return irq;
113}
114
115static void xive_irq_bitmap_free(int irq)
116{
117	unsigned long flags;
118	struct xive_irq_bitmap *xibm;
119
120	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
121		if ((irq >= xibm->base) && (irq < xibm->base + xibm->count)) {
122			spin_lock_irqsave(&xibm->lock, flags);
123			clear_bit(irq - xibm->base, xibm->bitmap);
124			spin_unlock_irqrestore(&xibm->lock, flags);
125			break;
126		}
127	}
128}
129
130
131/* Based on the similar routines in RTAS */
132static unsigned int plpar_busy_delay_time(long rc)
133{
134	unsigned int ms = 0;
135
136	if (H_IS_LONG_BUSY(rc)) {
137		ms = get_longbusy_msecs(rc);
138	} else if (rc == H_BUSY) {
139		ms = 10; /* seems appropriate for XIVE hcalls */
140	}
141
142	return ms;
143}
144
145static unsigned int plpar_busy_delay(int rc)
146{
147	unsigned int ms;
148
149	ms = plpar_busy_delay_time(rc);
150	if (ms)
151		mdelay(ms);
152
153	return ms;
154}
155
156/*
157 * Note: this call has a partition wide scope and can take a while to
158 * complete. If it returns H_LONG_BUSY_* it should be retried
159 * periodically.
160 */
161static long plpar_int_reset(unsigned long flags)
162{
163	long rc;
164
165	do {
166		rc = plpar_hcall_norets(H_INT_RESET, flags);
167	} while (plpar_busy_delay(rc));
168
169	if (rc)
170		pr_err("H_INT_RESET failed %ld\n", rc);
171
172	return rc;
173}
174
175static long plpar_int_get_source_info(unsigned long flags,
176				      unsigned long lisn,
177				      unsigned long *src_flags,
178				      unsigned long *eoi_page,
179				      unsigned long *trig_page,
180				      unsigned long *esb_shift)
181{
182	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
183	long rc;
184
185	do {
186		rc = plpar_hcall(H_INT_GET_SOURCE_INFO, retbuf, flags, lisn);
187	} while (plpar_busy_delay(rc));
188
189	if (rc) {
190		pr_err("H_INT_GET_SOURCE_INFO lisn=0x%lx failed %ld\n", lisn, rc);
191		return rc;
192	}
193
194	*src_flags = retbuf[0];
195	*eoi_page  = retbuf[1];
196	*trig_page = retbuf[2];
197	*esb_shift = retbuf[3];
198
199	pr_debug("H_INT_GET_SOURCE_INFO lisn=0x%lx flags=0x%lx eoi=0x%lx trig=0x%lx shift=0x%lx\n",
200		 lisn, retbuf[0], retbuf[1], retbuf[2], retbuf[3]);
201
202	return 0;
203}
204
205#define XIVE_SRC_SET_EISN (1ull << (63 - 62))
206#define XIVE_SRC_MASK     (1ull << (63 - 63)) /* unused */
207
208static long plpar_int_set_source_config(unsigned long flags,
209					unsigned long lisn,
210					unsigned long target,
211					unsigned long prio,
212					unsigned long sw_irq)
213{
214	long rc;
215
216
217	pr_debug("H_INT_SET_SOURCE_CONFIG flags=0x%lx lisn=0x%lx target=%ld prio=%ld sw_irq=%ld\n",
218		 flags, lisn, target, prio, sw_irq);
219
220
221	do {
222		rc = plpar_hcall_norets(H_INT_SET_SOURCE_CONFIG, flags, lisn,
223					target, prio, sw_irq);
224	} while (plpar_busy_delay(rc));
225
226	if (rc) {
227		pr_err("H_INT_SET_SOURCE_CONFIG lisn=0x%lx target=%ld prio=%ld failed %ld\n",
228		       lisn, target, prio, rc);
229		return rc;
230	}
231
232	return 0;
233}
234
235static long plpar_int_get_source_config(unsigned long flags,
236					unsigned long lisn,
237					unsigned long *target,
238					unsigned long *prio,
239					unsigned long *sw_irq)
240{
241	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
242	long rc;
243
244	pr_debug("H_INT_GET_SOURCE_CONFIG flags=0x%lx lisn=0x%lx\n", flags, lisn);
245
246	do {
247		rc = plpar_hcall(H_INT_GET_SOURCE_CONFIG, retbuf, flags, lisn,
248				 target, prio, sw_irq);
249	} while (plpar_busy_delay(rc));
250
251	if (rc) {
252		pr_err("H_INT_GET_SOURCE_CONFIG lisn=0x%lx failed %ld\n",
253		       lisn, rc);
254		return rc;
255	}
256
257	*target = retbuf[0];
258	*prio   = retbuf[1];
259	*sw_irq = retbuf[2];
260
261	pr_debug("H_INT_GET_SOURCE_CONFIG target=%ld prio=%ld sw_irq=%ld\n",
262		 retbuf[0], retbuf[1], retbuf[2]);
263
264	return 0;
265}
266
267static long plpar_int_get_queue_info(unsigned long flags,
268				     unsigned long target,
269				     unsigned long priority,
270				     unsigned long *esn_page,
271				     unsigned long *esn_size)
272{
273	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
274	long rc;
275
276	do {
277		rc = plpar_hcall(H_INT_GET_QUEUE_INFO, retbuf, flags, target,
278				 priority);
279	} while (plpar_busy_delay(rc));
280
281	if (rc) {
282		pr_err("H_INT_GET_QUEUE_INFO cpu=%ld prio=%ld failed %ld\n",
283		       target, priority, rc);
284		return rc;
285	}
286
287	*esn_page = retbuf[0];
288	*esn_size = retbuf[1];
289
290	pr_debug("H_INT_GET_QUEUE_INFO cpu=%ld prio=%ld page=0x%lx size=0x%lx\n",
291		 target, priority, retbuf[0], retbuf[1]);
292
293	return 0;
294}
295
296#define XIVE_EQ_ALWAYS_NOTIFY (1ull << (63 - 63))
297
298static long plpar_int_set_queue_config(unsigned long flags,
299				       unsigned long target,
300				       unsigned long priority,
301				       unsigned long qpage,
302				       unsigned long qsize)
303{
304	long rc;
305
306	pr_debug("H_INT_SET_QUEUE_CONFIG flags=0x%lx target=%ld priority=0x%lx qpage=0x%lx qsize=0x%lx\n",
307		 flags,  target, priority, qpage, qsize);
308
309	do {
310		rc = plpar_hcall_norets(H_INT_SET_QUEUE_CONFIG, flags, target,
311					priority, qpage, qsize);
312	} while (plpar_busy_delay(rc));
313
314	if (rc) {
315		pr_err("H_INT_SET_QUEUE_CONFIG cpu=%ld prio=%ld qpage=0x%lx returned %ld\n",
316		       target, priority, qpage, rc);
317		return  rc;
318	}
319
320	return 0;
321}
322
323static long plpar_int_sync(unsigned long flags, unsigned long lisn)
324{
325	long rc;
326
327	do {
328		rc = plpar_hcall_norets(H_INT_SYNC, flags, lisn);
329	} while (plpar_busy_delay(rc));
330
331	if (rc) {
332		pr_err("H_INT_SYNC lisn=0x%lx returned %ld\n", lisn, rc);
333		return  rc;
334	}
335
336	return 0;
337}
338
339#define XIVE_ESB_FLAG_STORE (1ull << (63 - 63))
340
341static long plpar_int_esb(unsigned long flags,
342			  unsigned long lisn,
343			  unsigned long offset,
344			  unsigned long in_data,
345			  unsigned long *out_data)
346{
347	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
348	long rc;
349
350	pr_debug("H_INT_ESB flags=0x%lx lisn=0x%lx offset=0x%lx in=0x%lx\n",
351		 flags,  lisn, offset, in_data);
352
353	do {
354		rc = plpar_hcall(H_INT_ESB, retbuf, flags, lisn, offset,
355				 in_data);
356	} while (plpar_busy_delay(rc));
357
358	if (rc) {
359		pr_err("H_INT_ESB lisn=0x%lx offset=0x%lx returned %ld\n",
360		       lisn, offset, rc);
361		return  rc;
362	}
363
364	*out_data = retbuf[0];
365
366	return 0;
367}
368
369static u64 xive_spapr_esb_rw(u32 lisn, u32 offset, u64 data, bool write)
370{
371	unsigned long read_data;
372	long rc;
373
374	rc = plpar_int_esb(write ? XIVE_ESB_FLAG_STORE : 0,
375			   lisn, offset, data, &read_data);
376	if (rc)
377		return -1;
378
379	return write ? 0 : read_data;
380}
381
382#define XIVE_SRC_H_INT_ESB     (1ull << (63 - 60))
383#define XIVE_SRC_LSI           (1ull << (63 - 61))
384#define XIVE_SRC_TRIGGER       (1ull << (63 - 62))
385#define XIVE_SRC_STORE_EOI     (1ull << (63 - 63))
386
387static int xive_spapr_populate_irq_data(u32 hw_irq, struct xive_irq_data *data)
388{
389	long rc;
390	unsigned long flags;
391	unsigned long eoi_page;
392	unsigned long trig_page;
393	unsigned long esb_shift;
394
395	memset(data, 0, sizeof(*data));
396
397	rc = plpar_int_get_source_info(0, hw_irq, &flags, &eoi_page, &trig_page,
398				       &esb_shift);
399	if (rc)
400		return  -EINVAL;
401
402	if (flags & XIVE_SRC_H_INT_ESB)
403		data->flags  |= XIVE_IRQ_FLAG_H_INT_ESB;
404	if (flags & XIVE_SRC_STORE_EOI)
405		data->flags  |= XIVE_IRQ_FLAG_STORE_EOI;
406	if (flags & XIVE_SRC_LSI)
407		data->flags  |= XIVE_IRQ_FLAG_LSI;
408	data->eoi_page  = eoi_page;
409	data->esb_shift = esb_shift;
410	data->trig_page = trig_page;
411
412	data->hw_irq = hw_irq;
413
414	/*
415	 * No chip-id for the sPAPR backend. This has an impact how we
416	 * pick a target. See xive_pick_irq_target().
417	 */
418	data->src_chip = XIVE_INVALID_CHIP_ID;
419
420	/*
421	 * When the H_INT_ESB flag is set, the H_INT_ESB hcall should
422	 * be used for interrupt management. Skip the remapping of the
423	 * ESB pages which are not available.
424	 */
425	if (data->flags & XIVE_IRQ_FLAG_H_INT_ESB)
426		return 0;
427
428	data->eoi_mmio = ioremap(data->eoi_page, 1u << data->esb_shift);
429	if (!data->eoi_mmio) {
430		pr_err("Failed to map EOI page for irq 0x%x\n", hw_irq);
431		return -ENOMEM;
432	}
433
434	/* Full function page supports trigger */
435	if (flags & XIVE_SRC_TRIGGER) {
436		data->trig_mmio = data->eoi_mmio;
437		return 0;
438	}
439
440	data->trig_mmio = ioremap(data->trig_page, 1u << data->esb_shift);
441	if (!data->trig_mmio) {
442		iounmap(data->eoi_mmio);
443		pr_err("Failed to map trigger page for irq 0x%x\n", hw_irq);
444		return -ENOMEM;
445	}
446	return 0;
447}
448
449static int xive_spapr_configure_irq(u32 hw_irq, u32 target, u8 prio, u32 sw_irq)
450{
451	long rc;
452
453	rc = plpar_int_set_source_config(XIVE_SRC_SET_EISN, hw_irq, target,
454					 prio, sw_irq);
455
456	return rc == 0 ? 0 : -ENXIO;
457}
458
459static int xive_spapr_get_irq_config(u32 hw_irq, u32 *target, u8 *prio,
460				     u32 *sw_irq)
461{
462	long rc;
463	unsigned long h_target;
464	unsigned long h_prio;
465	unsigned long h_sw_irq;
466
467	rc = plpar_int_get_source_config(0, hw_irq, &h_target, &h_prio,
468					 &h_sw_irq);
469
470	*target = h_target;
471	*prio = h_prio;
472	*sw_irq = h_sw_irq;
473
474	return rc == 0 ? 0 : -ENXIO;
475}
476
477/* This can be called multiple time to change a queue configuration */
478static int xive_spapr_configure_queue(u32 target, struct xive_q *q, u8 prio,
479				   __be32 *qpage, u32 order)
480{
481	s64 rc = 0;
482	unsigned long esn_page;
483	unsigned long esn_size;
484	u64 flags, qpage_phys;
485
486	/* If there's an actual queue page, clean it */
487	if (order) {
488		if (WARN_ON(!qpage))
489			return -EINVAL;
490		qpage_phys = __pa(qpage);
491	} else {
492		qpage_phys = 0;
493	}
494
495	/* Initialize the rest of the fields */
496	q->msk = order ? ((1u << (order - 2)) - 1) : 0;
497	q->idx = 0;
498	q->toggle = 0;
499
500	rc = plpar_int_get_queue_info(0, target, prio, &esn_page, &esn_size);
501	if (rc) {
502		pr_err("Error %lld getting queue info CPU %d prio %d\n", rc,
503		       target, prio);
504		rc = -EIO;
505		goto fail;
506	}
507
508	/* TODO: add support for the notification page */
509	q->eoi_phys = esn_page;
510
511	/* Default is to always notify */
512	flags = XIVE_EQ_ALWAYS_NOTIFY;
513
514	/* Configure and enable the queue in HW */
515	rc = plpar_int_set_queue_config(flags, target, prio, qpage_phys, order);
516	if (rc) {
517		pr_err("Error %lld setting queue for CPU %d prio %d\n", rc,
518		       target, prio);
519		rc = -EIO;
520	} else {
521		q->qpage = qpage;
522		if (is_secure_guest())
523			uv_share_page(PHYS_PFN(qpage_phys),
524					1 << xive_alloc_order(order));
525	}
526fail:
527	return rc;
528}
529
530static int xive_spapr_setup_queue(unsigned int cpu, struct xive_cpu *xc,
531				  u8 prio)
532{
533	struct xive_q *q = &xc->queue[prio];
534	__be32 *qpage;
535
536	qpage = xive_queue_page_alloc(cpu, xive_queue_shift);
537	if (IS_ERR(qpage))
538		return PTR_ERR(qpage);
539
540	return xive_spapr_configure_queue(get_hard_smp_processor_id(cpu),
541					  q, prio, qpage, xive_queue_shift);
542}
543
544static void xive_spapr_cleanup_queue(unsigned int cpu, struct xive_cpu *xc,
545				  u8 prio)
546{
547	struct xive_q *q = &xc->queue[prio];
548	unsigned int alloc_order;
549	long rc;
550	int hw_cpu = get_hard_smp_processor_id(cpu);
551
552	rc = plpar_int_set_queue_config(0, hw_cpu, prio, 0, 0);
553	if (rc)
554		pr_err("Error %ld setting queue for CPU %d prio %d\n", rc,
555		       hw_cpu, prio);
556
557	alloc_order = xive_alloc_order(xive_queue_shift);
558	if (is_secure_guest())
559		uv_unshare_page(PHYS_PFN(__pa(q->qpage)), 1 << alloc_order);
560	free_pages((unsigned long)q->qpage, alloc_order);
561	q->qpage = NULL;
562}
563
564static bool xive_spapr_match(struct device_node *node)
565{
566	/* Ignore cascaded controllers for the moment */
567	return true;
568}
569
570#ifdef CONFIG_SMP
571static int xive_spapr_get_ipi(unsigned int cpu, struct xive_cpu *xc)
572{
573	int irq = xive_irq_bitmap_alloc();
574
575	if (irq < 0) {
576		pr_err("Failed to allocate IPI on CPU %d\n", cpu);
577		return -ENXIO;
578	}
579
580	xc->hw_ipi = irq;
581	return 0;
582}
583
584static void xive_spapr_put_ipi(unsigned int cpu, struct xive_cpu *xc)
585{
586	if (xc->hw_ipi == XIVE_BAD_IRQ)
587		return;
588
589	xive_irq_bitmap_free(xc->hw_ipi);
590	xc->hw_ipi = XIVE_BAD_IRQ;
591}
592#endif /* CONFIG_SMP */
593
594static void xive_spapr_shutdown(void)
595{
596	plpar_int_reset(0);
597}
598
599/*
600 * Perform an "ack" cycle on the current thread. Grab the pending
601 * active priorities and update the CPPR to the most favored one.
602 */
603static void xive_spapr_update_pending(struct xive_cpu *xc)
604{
605	u8 nsr, cppr;
606	u16 ack;
607
608	/*
609	 * Perform the "Acknowledge O/S to Register" cycle.
610	 *
611	 * Let's speedup the access to the TIMA using the raw I/O
612	 * accessor as we don't need the synchronisation routine of
613	 * the higher level ones
614	 */
615	ack = be16_to_cpu(__raw_readw(xive_tima + TM_SPC_ACK_OS_REG));
616
617	/* Synchronize subsequent queue accesses */
618	mb();
619
620	/*
621	 * Grab the CPPR and the "NSR" field which indicates the source
622	 * of the interrupt (if any)
623	 */
624	cppr = ack & 0xff;
625	nsr = ack >> 8;
626
627	if (nsr & TM_QW1_NSR_EO) {
628		if (cppr == 0xff)
629			return;
630		/* Mark the priority pending */
631		xc->pending_prio |= 1 << cppr;
632
633		/*
634		 * A new interrupt should never have a CPPR less favored
635		 * than our current one.
636		 */
637		if (cppr >= xc->cppr)
638			pr_err("CPU %d odd ack CPPR, got %d at %d\n",
639			       smp_processor_id(), cppr, xc->cppr);
640
641		/* Update our idea of what the CPPR is */
642		xc->cppr = cppr;
643	}
644}
645
646static void xive_spapr_setup_cpu(unsigned int cpu, struct xive_cpu *xc)
647{
648	/* Only some debug on the TIMA settings */
649	pr_debug("(HW value: %08x %08x %08x)\n",
650		 in_be32(xive_tima + TM_QW1_OS + TM_WORD0),
651		 in_be32(xive_tima + TM_QW1_OS + TM_WORD1),
652		 in_be32(xive_tima + TM_QW1_OS + TM_WORD2));
653}
654
655static void xive_spapr_teardown_cpu(unsigned int cpu, struct xive_cpu *xc)
656{
657	/* Nothing to do */;
658}
659
660static void xive_spapr_sync_source(u32 hw_irq)
661{
662	/* Specs are unclear on what this is doing */
663	plpar_int_sync(0, hw_irq);
664}
665
666static int xive_spapr_debug_show(struct seq_file *m, void *private)
667{
668	struct xive_irq_bitmap *xibm;
669	char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
670
671	if (!buf)
672		return -ENOMEM;
673
674	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
675		memset(buf, 0, PAGE_SIZE);
676		bitmap_print_to_pagebuf(true, buf, xibm->bitmap, xibm->count);
677		seq_printf(m, "bitmap #%d: %s", xibm->count, buf);
678	}
679	kfree(buf);
680
681	return 0;
682}
683
684static const struct xive_ops xive_spapr_ops = {
685	.populate_irq_data	= xive_spapr_populate_irq_data,
686	.configure_irq		= xive_spapr_configure_irq,
687	.get_irq_config		= xive_spapr_get_irq_config,
688	.setup_queue		= xive_spapr_setup_queue,
689	.cleanup_queue		= xive_spapr_cleanup_queue,
690	.match			= xive_spapr_match,
691	.shutdown		= xive_spapr_shutdown,
692	.update_pending		= xive_spapr_update_pending,
693	.setup_cpu		= xive_spapr_setup_cpu,
694	.teardown_cpu		= xive_spapr_teardown_cpu,
695	.sync_source		= xive_spapr_sync_source,
696	.esb_rw			= xive_spapr_esb_rw,
697#ifdef CONFIG_SMP
698	.get_ipi		= xive_spapr_get_ipi,
699	.put_ipi		= xive_spapr_put_ipi,
700	.debug_show		= xive_spapr_debug_show,
701#endif /* CONFIG_SMP */
702	.name			= "spapr",
703};
704
705/*
706 * get max priority from "/ibm,plat-res-int-priorities"
707 */
708static bool __init xive_get_max_prio(u8 *max_prio)
709{
710	struct device_node *rootdn;
711	const __be32 *reg;
712	u32 len;
713	int prio, found;
714
715	rootdn = of_find_node_by_path("/");
716	if (!rootdn) {
717		pr_err("not root node found !\n");
718		return false;
719	}
720
721	reg = of_get_property(rootdn, "ibm,plat-res-int-priorities", &len);
722	of_node_put(rootdn);
723	if (!reg) {
724		pr_err("Failed to read 'ibm,plat-res-int-priorities' property\n");
725		return false;
726	}
727
728	if (len % (2 * sizeof(u32)) != 0) {
729		pr_err("invalid 'ibm,plat-res-int-priorities' property\n");
730		return false;
731	}
732
733	/* HW supports priorities in the range [0-7] and 0xFF is a
734	 * wildcard priority used to mask. We scan the ranges reserved
735	 * by the hypervisor to find the lowest priority we can use.
736	 */
737	found = 0xFF;
738	for (prio = 0; prio < 8; prio++) {
739		int reserved = 0;
740		int i;
741
742		for (i = 0; i < len / (2 * sizeof(u32)); i++) {
743			int base  = be32_to_cpu(reg[2 * i]);
744			int range = be32_to_cpu(reg[2 * i + 1]);
745
746			if (prio >= base && prio < base + range)
747				reserved++;
748		}
749
750		if (!reserved)
751			found = prio;
752	}
753
754	if (found == 0xFF) {
755		pr_err("no valid priority found in 'ibm,plat-res-int-priorities'\n");
756		return false;
757	}
758
759	*max_prio = found;
760	return true;
761}
762
763static const u8 *__init get_vec5_feature(unsigned int index)
764{
765	unsigned long root, chosen;
766	int size;
767	const u8 *vec5;
768
769	root = of_get_flat_dt_root();
770	chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
771	if (chosen == -FDT_ERR_NOTFOUND)
772		return NULL;
773
774	vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size);
775	if (!vec5)
776		return NULL;
777
778	if (size <= index)
779		return NULL;
780
781	return vec5 + index;
782}
783
784static bool __init xive_spapr_disabled(void)
785{
786	const u8 *vec5_xive;
787
788	vec5_xive = get_vec5_feature(OV5_INDX(OV5_XIVE_SUPPORT));
789	if (vec5_xive) {
790		u8 val;
791
792		val = *vec5_xive & OV5_FEAT(OV5_XIVE_SUPPORT);
793		switch (val) {
794		case OV5_FEAT(OV5_XIVE_EITHER):
795		case OV5_FEAT(OV5_XIVE_LEGACY):
796			break;
797		case OV5_FEAT(OV5_XIVE_EXPLOIT):
798			/* Hypervisor only supports XIVE */
799			if (xive_cmdline_disabled)
800				pr_warn("WARNING: Ignoring cmdline option xive=off\n");
801			return false;
802		default:
803			pr_warn("%s: Unknown xive support option: 0x%x\n",
804				__func__, val);
805			break;
806		}
807	}
808
809	return xive_cmdline_disabled;
810}
811
812bool __init xive_spapr_init(void)
813{
814	struct device_node *np;
815	struct resource r;
816	void __iomem *tima;
817	struct property *prop;
818	u8 max_prio;
819	u32 val;
820	u32 len;
821	const __be32 *reg;
822	int i, err;
823
824	if (xive_spapr_disabled())
825		return false;
826
827	pr_devel("%s()\n", __func__);
828	np = of_find_compatible_node(NULL, NULL, "ibm,power-ivpe");
829	if (!np) {
830		pr_devel("not found !\n");
831		return false;
832	}
833	pr_devel("Found %s\n", np->full_name);
834
835	/* Resource 1 is the OS ring TIMA */
836	if (of_address_to_resource(np, 1, &r)) {
837		pr_err("Failed to get thread mgmnt area resource\n");
838		goto err_put;
839	}
840	tima = ioremap(r.start, resource_size(&r));
841	if (!tima) {
842		pr_err("Failed to map thread mgmnt area\n");
843		goto err_put;
844	}
845
846	if (!xive_get_max_prio(&max_prio))
847		goto err_unmap;
848
849	/* Feed the IRQ number allocator with the ranges given in the DT */
850	reg = of_get_property(np, "ibm,xive-lisn-ranges", &len);
851	if (!reg) {
852		pr_err("Failed to read 'ibm,xive-lisn-ranges' property\n");
853		goto err_unmap;
854	}
855
856	if (len % (2 * sizeof(u32)) != 0) {
857		pr_err("invalid 'ibm,xive-lisn-ranges' property\n");
858		goto err_unmap;
859	}
860
861	for (i = 0; i < len / (2 * sizeof(u32)); i++, reg += 2) {
862		err = xive_irq_bitmap_add(be32_to_cpu(reg[0]),
863					  be32_to_cpu(reg[1]));
864		if (err < 0)
865			goto err_mem_free;
866	}
867
868	/* Iterate the EQ sizes and pick one */
869	of_property_for_each_u32(np, "ibm,xive-eq-sizes", prop, reg, val) {
870		xive_queue_shift = val;
871		if (val == PAGE_SHIFT)
872			break;
873	}
874
875	/* Initialize XIVE core with our backend */
876	if (!xive_core_init(np, &xive_spapr_ops, tima, TM_QW1_OS, max_prio))
877		goto err_mem_free;
878
879	of_node_put(np);
880	pr_info("Using %dkB queues\n", 1 << (xive_queue_shift - 10));
881	return true;
882
883err_mem_free:
884	xive_irq_bitmap_remove_all();
885err_unmap:
886	iounmap(tima);
887err_put:
888	of_node_put(np);
889	return false;
890}
891
892machine_arch_initcall(pseries, xive_core_debug_init);
893