xref: /openbmc/linux/arch/powerpc/sysdev/xive/spapr.c (revision 3cf3cdea)
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/slab.h>
15 #include <linux/spinlock.h>
16 #include <linux/cpumask.h>
17 #include <linux/mm.h>
18 #include <linux/delay.h>
19 #include <linux/libfdt.h>
20 
21 #include <asm/machdep.h>
22 #include <asm/prom.h>
23 #include <asm/io.h>
24 #include <asm/smp.h>
25 #include <asm/irq.h>
26 #include <asm/errno.h>
27 #include <asm/xive.h>
28 #include <asm/xive-regs.h>
29 #include <asm/hvcall.h>
30 #include <asm/svm.h>
31 #include <asm/ultravisor.h>
32 
33 #include "xive-internal.h"
34 
35 static u32 xive_queue_shift;
36 
37 struct xive_irq_bitmap {
38 	unsigned long		*bitmap;
39 	unsigned int		base;
40 	unsigned int		count;
41 	spinlock_t		lock;
42 	struct list_head	list;
43 };
44 
45 static LIST_HEAD(xive_irq_bitmaps);
46 
47 static int xive_irq_bitmap_add(int base, int count)
48 {
49 	struct xive_irq_bitmap *xibm;
50 
51 	xibm = kzalloc(sizeof(*xibm), GFP_KERNEL);
52 	if (!xibm)
53 		return -ENOMEM;
54 
55 	spin_lock_init(&xibm->lock);
56 	xibm->base = base;
57 	xibm->count = count;
58 	xibm->bitmap = kzalloc(xibm->count, GFP_KERNEL);
59 	if (!xibm->bitmap) {
60 		kfree(xibm);
61 		return -ENOMEM;
62 	}
63 	list_add(&xibm->list, &xive_irq_bitmaps);
64 
65 	pr_info("Using IRQ range [%x-%x]", xibm->base,
66 		xibm->base + xibm->count - 1);
67 	return 0;
68 }
69 
70 static int __xive_irq_bitmap_alloc(struct xive_irq_bitmap *xibm)
71 {
72 	int irq;
73 
74 	irq = find_first_zero_bit(xibm->bitmap, xibm->count);
75 	if (irq != xibm->count) {
76 		set_bit(irq, xibm->bitmap);
77 		irq += xibm->base;
78 	} else {
79 		irq = -ENOMEM;
80 	}
81 
82 	return irq;
83 }
84 
85 static int xive_irq_bitmap_alloc(void)
86 {
87 	struct xive_irq_bitmap *xibm;
88 	unsigned long flags;
89 	int irq = -ENOENT;
90 
91 	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
92 		spin_lock_irqsave(&xibm->lock, flags);
93 		irq = __xive_irq_bitmap_alloc(xibm);
94 		spin_unlock_irqrestore(&xibm->lock, flags);
95 		if (irq >= 0)
96 			break;
97 	}
98 	return irq;
99 }
100 
101 static void xive_irq_bitmap_free(int irq)
102 {
103 	unsigned long flags;
104 	struct xive_irq_bitmap *xibm;
105 
106 	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
107 		if ((irq >= xibm->base) && (irq < xibm->base + xibm->count)) {
108 			spin_lock_irqsave(&xibm->lock, flags);
109 			clear_bit(irq - xibm->base, xibm->bitmap);
110 			spin_unlock_irqrestore(&xibm->lock, flags);
111 			break;
112 		}
113 	}
114 }
115 
116 
117 /* Based on the similar routines in RTAS */
118 static unsigned int plpar_busy_delay_time(long rc)
119 {
120 	unsigned int ms = 0;
121 
122 	if (H_IS_LONG_BUSY(rc)) {
123 		ms = get_longbusy_msecs(rc);
124 	} else if (rc == H_BUSY) {
125 		ms = 10; /* seems appropriate for XIVE hcalls */
126 	}
127 
128 	return ms;
129 }
130 
131 static unsigned int plpar_busy_delay(int rc)
132 {
133 	unsigned int ms;
134 
135 	ms = plpar_busy_delay_time(rc);
136 	if (ms)
137 		mdelay(ms);
138 
139 	return ms;
140 }
141 
142 /*
143  * Note: this call has a partition wide scope and can take a while to
144  * complete. If it returns H_LONG_BUSY_* it should be retried
145  * periodically.
146  */
147 static long plpar_int_reset(unsigned long flags)
148 {
149 	long rc;
150 
151 	do {
152 		rc = plpar_hcall_norets(H_INT_RESET, flags);
153 	} while (plpar_busy_delay(rc));
154 
155 	if (rc)
156 		pr_err("H_INT_RESET failed %ld\n", rc);
157 
158 	return rc;
159 }
160 
161 static long plpar_int_get_source_info(unsigned long flags,
162 				      unsigned long lisn,
163 				      unsigned long *src_flags,
164 				      unsigned long *eoi_page,
165 				      unsigned long *trig_page,
166 				      unsigned long *esb_shift)
167 {
168 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
169 	long rc;
170 
171 	do {
172 		rc = plpar_hcall(H_INT_GET_SOURCE_INFO, retbuf, flags, lisn);
173 	} while (plpar_busy_delay(rc));
174 
175 	if (rc) {
176 		pr_err("H_INT_GET_SOURCE_INFO lisn=%ld failed %ld\n", lisn, rc);
177 		return rc;
178 	}
179 
180 	*src_flags = retbuf[0];
181 	*eoi_page  = retbuf[1];
182 	*trig_page = retbuf[2];
183 	*esb_shift = retbuf[3];
184 
185 	pr_devel("H_INT_GET_SOURCE_INFO flags=%lx eoi=%lx trig=%lx shift=%lx\n",
186 		retbuf[0], retbuf[1], retbuf[2], retbuf[3]);
187 
188 	return 0;
189 }
190 
191 #define XIVE_SRC_SET_EISN (1ull << (63 - 62))
192 #define XIVE_SRC_MASK     (1ull << (63 - 63)) /* unused */
193 
194 static long plpar_int_set_source_config(unsigned long flags,
195 					unsigned long lisn,
196 					unsigned long target,
197 					unsigned long prio,
198 					unsigned long sw_irq)
199 {
200 	long rc;
201 
202 
203 	pr_devel("H_INT_SET_SOURCE_CONFIG flags=%lx lisn=%lx target=%lx prio=%lx sw_irq=%lx\n",
204 		flags, lisn, target, prio, sw_irq);
205 
206 
207 	do {
208 		rc = plpar_hcall_norets(H_INT_SET_SOURCE_CONFIG, flags, lisn,
209 					target, prio, sw_irq);
210 	} while (plpar_busy_delay(rc));
211 
212 	if (rc) {
213 		pr_err("H_INT_SET_SOURCE_CONFIG lisn=%ld target=%lx prio=%lx failed %ld\n",
214 		       lisn, target, prio, rc);
215 		return rc;
216 	}
217 
218 	return 0;
219 }
220 
221 static long plpar_int_get_source_config(unsigned long flags,
222 					unsigned long lisn,
223 					unsigned long *target,
224 					unsigned long *prio,
225 					unsigned long *sw_irq)
226 {
227 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
228 	long rc;
229 
230 	pr_devel("H_INT_GET_SOURCE_CONFIG flags=%lx lisn=%lx\n", flags, lisn);
231 
232 	do {
233 		rc = plpar_hcall(H_INT_GET_SOURCE_CONFIG, retbuf, flags, lisn,
234 				 target, prio, sw_irq);
235 	} while (plpar_busy_delay(rc));
236 
237 	if (rc) {
238 		pr_err("H_INT_GET_SOURCE_CONFIG lisn=%ld failed %ld\n",
239 		       lisn, rc);
240 		return rc;
241 	}
242 
243 	*target = retbuf[0];
244 	*prio   = retbuf[1];
245 	*sw_irq = retbuf[2];
246 
247 	pr_devel("H_INT_GET_SOURCE_CONFIG target=%lx prio=%lx sw_irq=%lx\n",
248 		retbuf[0], retbuf[1], retbuf[2]);
249 
250 	return 0;
251 }
252 
253 static long plpar_int_get_queue_info(unsigned long flags,
254 				     unsigned long target,
255 				     unsigned long priority,
256 				     unsigned long *esn_page,
257 				     unsigned long *esn_size)
258 {
259 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
260 	long rc;
261 
262 	do {
263 		rc = plpar_hcall(H_INT_GET_QUEUE_INFO, retbuf, flags, target,
264 				 priority);
265 	} while (plpar_busy_delay(rc));
266 
267 	if (rc) {
268 		pr_err("H_INT_GET_QUEUE_INFO cpu=%ld prio=%ld failed %ld\n",
269 		       target, priority, rc);
270 		return rc;
271 	}
272 
273 	*esn_page = retbuf[0];
274 	*esn_size = retbuf[1];
275 
276 	pr_devel("H_INT_GET_QUEUE_INFO page=%lx size=%lx\n",
277 		retbuf[0], retbuf[1]);
278 
279 	return 0;
280 }
281 
282 #define XIVE_EQ_ALWAYS_NOTIFY (1ull << (63 - 63))
283 
284 static long plpar_int_set_queue_config(unsigned long flags,
285 				       unsigned long target,
286 				       unsigned long priority,
287 				       unsigned long qpage,
288 				       unsigned long qsize)
289 {
290 	long rc;
291 
292 	pr_devel("H_INT_SET_QUEUE_CONFIG flags=%lx target=%lx priority=%lx qpage=%lx qsize=%lx\n",
293 		flags,  target, priority, qpage, qsize);
294 
295 	do {
296 		rc = plpar_hcall_norets(H_INT_SET_QUEUE_CONFIG, flags, target,
297 					priority, qpage, qsize);
298 	} while (plpar_busy_delay(rc));
299 
300 	if (rc) {
301 		pr_err("H_INT_SET_QUEUE_CONFIG cpu=%ld prio=%ld qpage=%lx returned %ld\n",
302 		       target, priority, qpage, rc);
303 		return  rc;
304 	}
305 
306 	return 0;
307 }
308 
309 static long plpar_int_sync(unsigned long flags, unsigned long lisn)
310 {
311 	long rc;
312 
313 	do {
314 		rc = plpar_hcall_norets(H_INT_SYNC, flags, lisn);
315 	} while (plpar_busy_delay(rc));
316 
317 	if (rc) {
318 		pr_err("H_INT_SYNC lisn=%ld returned %ld\n", lisn, rc);
319 		return  rc;
320 	}
321 
322 	return 0;
323 }
324 
325 #define XIVE_ESB_FLAG_STORE (1ull << (63 - 63))
326 
327 static long plpar_int_esb(unsigned long flags,
328 			  unsigned long lisn,
329 			  unsigned long offset,
330 			  unsigned long in_data,
331 			  unsigned long *out_data)
332 {
333 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
334 	long rc;
335 
336 	pr_devel("H_INT_ESB flags=%lx lisn=%lx offset=%lx in=%lx\n",
337 		flags,  lisn, offset, in_data);
338 
339 	do {
340 		rc = plpar_hcall(H_INT_ESB, retbuf, flags, lisn, offset,
341 				 in_data);
342 	} while (plpar_busy_delay(rc));
343 
344 	if (rc) {
345 		pr_err("H_INT_ESB lisn=%ld offset=%ld returned %ld\n",
346 		       lisn, offset, rc);
347 		return  rc;
348 	}
349 
350 	*out_data = retbuf[0];
351 
352 	return 0;
353 }
354 
355 static u64 xive_spapr_esb_rw(u32 lisn, u32 offset, u64 data, bool write)
356 {
357 	unsigned long read_data;
358 	long rc;
359 
360 	rc = plpar_int_esb(write ? XIVE_ESB_FLAG_STORE : 0,
361 			   lisn, offset, data, &read_data);
362 	if (rc)
363 		return -1;
364 
365 	return write ? 0 : read_data;
366 }
367 
368 #define XIVE_SRC_H_INT_ESB     (1ull << (63 - 60))
369 #define XIVE_SRC_LSI           (1ull << (63 - 61))
370 #define XIVE_SRC_TRIGGER       (1ull << (63 - 62))
371 #define XIVE_SRC_STORE_EOI     (1ull << (63 - 63))
372 
373 static int xive_spapr_populate_irq_data(u32 hw_irq, struct xive_irq_data *data)
374 {
375 	long rc;
376 	unsigned long flags;
377 	unsigned long eoi_page;
378 	unsigned long trig_page;
379 	unsigned long esb_shift;
380 
381 	memset(data, 0, sizeof(*data));
382 
383 	rc = plpar_int_get_source_info(0, hw_irq, &flags, &eoi_page, &trig_page,
384 				       &esb_shift);
385 	if (rc)
386 		return  -EINVAL;
387 
388 	if (flags & XIVE_SRC_H_INT_ESB)
389 		data->flags  |= XIVE_IRQ_FLAG_H_INT_ESB;
390 	if (flags & XIVE_SRC_STORE_EOI)
391 		data->flags  |= XIVE_IRQ_FLAG_STORE_EOI;
392 	if (flags & XIVE_SRC_LSI)
393 		data->flags  |= XIVE_IRQ_FLAG_LSI;
394 	data->eoi_page  = eoi_page;
395 	data->esb_shift = esb_shift;
396 	data->trig_page = trig_page;
397 
398 	data->hw_irq = hw_irq;
399 
400 	/*
401 	 * No chip-id for the sPAPR backend. This has an impact how we
402 	 * pick a target. See xive_pick_irq_target().
403 	 */
404 	data->src_chip = XIVE_INVALID_CHIP_ID;
405 
406 	/*
407 	 * When the H_INT_ESB flag is set, the H_INT_ESB hcall should
408 	 * be used for interrupt management. Skip the remapping of the
409 	 * ESB pages which are not available.
410 	 */
411 	if (data->flags & XIVE_IRQ_FLAG_H_INT_ESB)
412 		return 0;
413 
414 	data->eoi_mmio = ioremap(data->eoi_page, 1u << data->esb_shift);
415 	if (!data->eoi_mmio) {
416 		pr_err("Failed to map EOI page for irq 0x%x\n", hw_irq);
417 		return -ENOMEM;
418 	}
419 
420 	/* Full function page supports trigger */
421 	if (flags & XIVE_SRC_TRIGGER) {
422 		data->trig_mmio = data->eoi_mmio;
423 		return 0;
424 	}
425 
426 	data->trig_mmio = ioremap(data->trig_page, 1u << data->esb_shift);
427 	if (!data->trig_mmio) {
428 		pr_err("Failed to map trigger page for irq 0x%x\n", hw_irq);
429 		return -ENOMEM;
430 	}
431 	return 0;
432 }
433 
434 static int xive_spapr_configure_irq(u32 hw_irq, u32 target, u8 prio, u32 sw_irq)
435 {
436 	long rc;
437 
438 	rc = plpar_int_set_source_config(XIVE_SRC_SET_EISN, hw_irq, target,
439 					 prio, sw_irq);
440 
441 	return rc == 0 ? 0 : -ENXIO;
442 }
443 
444 static int xive_spapr_get_irq_config(u32 hw_irq, u32 *target, u8 *prio,
445 				     u32 *sw_irq)
446 {
447 	long rc;
448 	unsigned long h_target;
449 	unsigned long h_prio;
450 	unsigned long h_sw_irq;
451 
452 	rc = plpar_int_get_source_config(0, hw_irq, &h_target, &h_prio,
453 					 &h_sw_irq);
454 
455 	*target = h_target;
456 	*prio = h_prio;
457 	*sw_irq = h_sw_irq;
458 
459 	return rc == 0 ? 0 : -ENXIO;
460 }
461 
462 /* This can be called multiple time to change a queue configuration */
463 static int xive_spapr_configure_queue(u32 target, struct xive_q *q, u8 prio,
464 				   __be32 *qpage, u32 order)
465 {
466 	s64 rc = 0;
467 	unsigned long esn_page;
468 	unsigned long esn_size;
469 	u64 flags, qpage_phys;
470 
471 	/* If there's an actual queue page, clean it */
472 	if (order) {
473 		if (WARN_ON(!qpage))
474 			return -EINVAL;
475 		qpage_phys = __pa(qpage);
476 	} else {
477 		qpage_phys = 0;
478 	}
479 
480 	/* Initialize the rest of the fields */
481 	q->msk = order ? ((1u << (order - 2)) - 1) : 0;
482 	q->idx = 0;
483 	q->toggle = 0;
484 
485 	rc = plpar_int_get_queue_info(0, target, prio, &esn_page, &esn_size);
486 	if (rc) {
487 		pr_err("Error %lld getting queue info CPU %d prio %d\n", rc,
488 		       target, prio);
489 		rc = -EIO;
490 		goto fail;
491 	}
492 
493 	/* TODO: add support for the notification page */
494 	q->eoi_phys = esn_page;
495 
496 	/* Default is to always notify */
497 	flags = XIVE_EQ_ALWAYS_NOTIFY;
498 
499 	/* Configure and enable the queue in HW */
500 	rc = plpar_int_set_queue_config(flags, target, prio, qpage_phys, order);
501 	if (rc) {
502 		pr_err("Error %lld setting queue for CPU %d prio %d\n", rc,
503 		       target, prio);
504 		rc = -EIO;
505 	} else {
506 		q->qpage = qpage;
507 		if (is_secure_guest())
508 			uv_share_page(PHYS_PFN(qpage_phys),
509 					1 << xive_alloc_order(order));
510 	}
511 fail:
512 	return rc;
513 }
514 
515 static int xive_spapr_setup_queue(unsigned int cpu, struct xive_cpu *xc,
516 				  u8 prio)
517 {
518 	struct xive_q *q = &xc->queue[prio];
519 	__be32 *qpage;
520 
521 	qpage = xive_queue_page_alloc(cpu, xive_queue_shift);
522 	if (IS_ERR(qpage))
523 		return PTR_ERR(qpage);
524 
525 	return xive_spapr_configure_queue(get_hard_smp_processor_id(cpu),
526 					  q, prio, qpage, xive_queue_shift);
527 }
528 
529 static void xive_spapr_cleanup_queue(unsigned int cpu, struct xive_cpu *xc,
530 				  u8 prio)
531 {
532 	struct xive_q *q = &xc->queue[prio];
533 	unsigned int alloc_order;
534 	long rc;
535 	int hw_cpu = get_hard_smp_processor_id(cpu);
536 
537 	rc = plpar_int_set_queue_config(0, hw_cpu, prio, 0, 0);
538 	if (rc)
539 		pr_err("Error %ld setting queue for CPU %d prio %d\n", rc,
540 		       hw_cpu, prio);
541 
542 	alloc_order = xive_alloc_order(xive_queue_shift);
543 	if (is_secure_guest())
544 		uv_unshare_page(PHYS_PFN(__pa(q->qpage)), 1 << alloc_order);
545 	free_pages((unsigned long)q->qpage, alloc_order);
546 	q->qpage = NULL;
547 }
548 
549 static bool xive_spapr_match(struct device_node *node)
550 {
551 	/* Ignore cascaded controllers for the moment */
552 	return true;
553 }
554 
555 #ifdef CONFIG_SMP
556 static int xive_spapr_get_ipi(unsigned int cpu, struct xive_cpu *xc)
557 {
558 	int irq = xive_irq_bitmap_alloc();
559 
560 	if (irq < 0) {
561 		pr_err("Failed to allocate IPI on CPU %d\n", cpu);
562 		return -ENXIO;
563 	}
564 
565 	xc->hw_ipi = irq;
566 	return 0;
567 }
568 
569 static void xive_spapr_put_ipi(unsigned int cpu, struct xive_cpu *xc)
570 {
571 	if (xc->hw_ipi == XIVE_BAD_IRQ)
572 		return;
573 
574 	xive_irq_bitmap_free(xc->hw_ipi);
575 	xc->hw_ipi = XIVE_BAD_IRQ;
576 }
577 #endif /* CONFIG_SMP */
578 
579 static void xive_spapr_shutdown(void)
580 {
581 	plpar_int_reset(0);
582 }
583 
584 /*
585  * Perform an "ack" cycle on the current thread. Grab the pending
586  * active priorities and update the CPPR to the most favored one.
587  */
588 static void xive_spapr_update_pending(struct xive_cpu *xc)
589 {
590 	u8 nsr, cppr;
591 	u16 ack;
592 
593 	/*
594 	 * Perform the "Acknowledge O/S to Register" cycle.
595 	 *
596 	 * Let's speedup the access to the TIMA using the raw I/O
597 	 * accessor as we don't need the synchronisation routine of
598 	 * the higher level ones
599 	 */
600 	ack = be16_to_cpu(__raw_readw(xive_tima + TM_SPC_ACK_OS_REG));
601 
602 	/* Synchronize subsequent queue accesses */
603 	mb();
604 
605 	/*
606 	 * Grab the CPPR and the "NSR" field which indicates the source
607 	 * of the interrupt (if any)
608 	 */
609 	cppr = ack & 0xff;
610 	nsr = ack >> 8;
611 
612 	if (nsr & TM_QW1_NSR_EO) {
613 		if (cppr == 0xff)
614 			return;
615 		/* Mark the priority pending */
616 		xc->pending_prio |= 1 << cppr;
617 
618 		/*
619 		 * A new interrupt should never have a CPPR less favored
620 		 * than our current one.
621 		 */
622 		if (cppr >= xc->cppr)
623 			pr_err("CPU %d odd ack CPPR, got %d at %d\n",
624 			       smp_processor_id(), cppr, xc->cppr);
625 
626 		/* Update our idea of what the CPPR is */
627 		xc->cppr = cppr;
628 	}
629 }
630 
631 static void xive_spapr_setup_cpu(unsigned int cpu, struct xive_cpu *xc)
632 {
633 	/* Only some debug on the TIMA settings */
634 	pr_debug("(HW value: %08x %08x %08x)\n",
635 		 in_be32(xive_tima + TM_QW1_OS + TM_WORD0),
636 		 in_be32(xive_tima + TM_QW1_OS + TM_WORD1),
637 		 in_be32(xive_tima + TM_QW1_OS + TM_WORD2));
638 }
639 
640 static void xive_spapr_teardown_cpu(unsigned int cpu, struct xive_cpu *xc)
641 {
642 	/* Nothing to do */;
643 }
644 
645 static void xive_spapr_sync_source(u32 hw_irq)
646 {
647 	/* Specs are unclear on what this is doing */
648 	plpar_int_sync(0, hw_irq);
649 }
650 
651 static int xive_spapr_debug_show(struct seq_file *m, void *private)
652 {
653 	struct xive_irq_bitmap *xibm;
654 	char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
655 
656 	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
657 		memset(buf, 0, PAGE_SIZE);
658 		bitmap_print_to_pagebuf(true, buf, xibm->bitmap, xibm->count);
659 		seq_printf(m, "bitmap #%d: %s", xibm->count, buf);
660 	}
661 	kfree(buf);
662 
663 	return 0;
664 }
665 
666 static const struct xive_ops xive_spapr_ops = {
667 	.populate_irq_data	= xive_spapr_populate_irq_data,
668 	.configure_irq		= xive_spapr_configure_irq,
669 	.get_irq_config		= xive_spapr_get_irq_config,
670 	.setup_queue		= xive_spapr_setup_queue,
671 	.cleanup_queue		= xive_spapr_cleanup_queue,
672 	.match			= xive_spapr_match,
673 	.shutdown		= xive_spapr_shutdown,
674 	.update_pending		= xive_spapr_update_pending,
675 	.setup_cpu		= xive_spapr_setup_cpu,
676 	.teardown_cpu		= xive_spapr_teardown_cpu,
677 	.sync_source		= xive_spapr_sync_source,
678 	.esb_rw			= xive_spapr_esb_rw,
679 #ifdef CONFIG_SMP
680 	.get_ipi		= xive_spapr_get_ipi,
681 	.put_ipi		= xive_spapr_put_ipi,
682 	.debug_show		= xive_spapr_debug_show,
683 #endif /* CONFIG_SMP */
684 	.name			= "spapr",
685 };
686 
687 /*
688  * get max priority from "/ibm,plat-res-int-priorities"
689  */
690 static bool xive_get_max_prio(u8 *max_prio)
691 {
692 	struct device_node *rootdn;
693 	const __be32 *reg;
694 	u32 len;
695 	int prio, found;
696 
697 	rootdn = of_find_node_by_path("/");
698 	if (!rootdn) {
699 		pr_err("not root node found !\n");
700 		return false;
701 	}
702 
703 	reg = of_get_property(rootdn, "ibm,plat-res-int-priorities", &len);
704 	if (!reg) {
705 		pr_err("Failed to read 'ibm,plat-res-int-priorities' property\n");
706 		return false;
707 	}
708 
709 	if (len % (2 * sizeof(u32)) != 0) {
710 		pr_err("invalid 'ibm,plat-res-int-priorities' property\n");
711 		return false;
712 	}
713 
714 	/* HW supports priorities in the range [0-7] and 0xFF is a
715 	 * wildcard priority used to mask. We scan the ranges reserved
716 	 * by the hypervisor to find the lowest priority we can use.
717 	 */
718 	found = 0xFF;
719 	for (prio = 0; prio < 8; prio++) {
720 		int reserved = 0;
721 		int i;
722 
723 		for (i = 0; i < len / (2 * sizeof(u32)); i++) {
724 			int base  = be32_to_cpu(reg[2 * i]);
725 			int range = be32_to_cpu(reg[2 * i + 1]);
726 
727 			if (prio >= base && prio < base + range)
728 				reserved++;
729 		}
730 
731 		if (!reserved)
732 			found = prio;
733 	}
734 
735 	if (found == 0xFF) {
736 		pr_err("no valid priority found in 'ibm,plat-res-int-priorities'\n");
737 		return false;
738 	}
739 
740 	*max_prio = found;
741 	return true;
742 }
743 
744 static const u8 *get_vec5_feature(unsigned int index)
745 {
746 	unsigned long root, chosen;
747 	int size;
748 	const u8 *vec5;
749 
750 	root = of_get_flat_dt_root();
751 	chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
752 	if (chosen == -FDT_ERR_NOTFOUND)
753 		return NULL;
754 
755 	vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size);
756 	if (!vec5)
757 		return NULL;
758 
759 	if (size <= index)
760 		return NULL;
761 
762 	return vec5 + index;
763 }
764 
765 static bool __init xive_spapr_disabled(void)
766 {
767 	const u8 *vec5_xive;
768 
769 	vec5_xive = get_vec5_feature(OV5_INDX(OV5_XIVE_SUPPORT));
770 	if (vec5_xive) {
771 		u8 val;
772 
773 		val = *vec5_xive & OV5_FEAT(OV5_XIVE_SUPPORT);
774 		switch (val) {
775 		case OV5_FEAT(OV5_XIVE_EITHER):
776 		case OV5_FEAT(OV5_XIVE_LEGACY):
777 			break;
778 		case OV5_FEAT(OV5_XIVE_EXPLOIT):
779 			/* Hypervisor only supports XIVE */
780 			if (xive_cmdline_disabled)
781 				pr_warn("WARNING: Ignoring cmdline option xive=off\n");
782 			return false;
783 		default:
784 			pr_warn("%s: Unknown xive support option: 0x%x\n",
785 				__func__, val);
786 			break;
787 		}
788 	}
789 
790 	return xive_cmdline_disabled;
791 }
792 
793 bool __init xive_spapr_init(void)
794 {
795 	struct device_node *np;
796 	struct resource r;
797 	void __iomem *tima;
798 	struct property *prop;
799 	u8 max_prio;
800 	u32 val;
801 	u32 len;
802 	const __be32 *reg;
803 	int i;
804 
805 	if (xive_spapr_disabled())
806 		return false;
807 
808 	pr_devel("%s()\n", __func__);
809 	np = of_find_compatible_node(NULL, NULL, "ibm,power-ivpe");
810 	if (!np) {
811 		pr_devel("not found !\n");
812 		return false;
813 	}
814 	pr_devel("Found %s\n", np->full_name);
815 
816 	/* Resource 1 is the OS ring TIMA */
817 	if (of_address_to_resource(np, 1, &r)) {
818 		pr_err("Failed to get thread mgmnt area resource\n");
819 		return false;
820 	}
821 	tima = ioremap(r.start, resource_size(&r));
822 	if (!tima) {
823 		pr_err("Failed to map thread mgmnt area\n");
824 		return false;
825 	}
826 
827 	if (!xive_get_max_prio(&max_prio))
828 		return false;
829 
830 	/* Feed the IRQ number allocator with the ranges given in the DT */
831 	reg = of_get_property(np, "ibm,xive-lisn-ranges", &len);
832 	if (!reg) {
833 		pr_err("Failed to read 'ibm,xive-lisn-ranges' property\n");
834 		return false;
835 	}
836 
837 	if (len % (2 * sizeof(u32)) != 0) {
838 		pr_err("invalid 'ibm,xive-lisn-ranges' property\n");
839 		return false;
840 	}
841 
842 	for (i = 0; i < len / (2 * sizeof(u32)); i++, reg += 2)
843 		xive_irq_bitmap_add(be32_to_cpu(reg[0]),
844 				    be32_to_cpu(reg[1]));
845 
846 	/* Iterate the EQ sizes and pick one */
847 	of_property_for_each_u32(np, "ibm,xive-eq-sizes", prop, reg, val) {
848 		xive_queue_shift = val;
849 		if (val == PAGE_SHIFT)
850 			break;
851 	}
852 
853 	/* Initialize XIVE core with our backend */
854 	if (!xive_core_init(np, &xive_spapr_ops, tima, TM_QW1_OS, max_prio))
855 		return false;
856 
857 	pr_info("Using %dkB queues\n", 1 << (xive_queue_shift - 10));
858 	return true;
859 }
860 
861 machine_arch_initcall(pseries, xive_core_debug_init);
862