Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 892 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/xive/spapr.c b/arch/powerpc/sysdev/xive/spapr.c
new file mode 100644
index 000000000..e45419264
--- /dev/null
+++ b/arch/powerpc/sysdev/xive/spapr.c
@@ -0,0 +1,892 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2016,2017 IBM Corporation.
+ */
+
+#define pr_fmt(fmt) "xive: " fmt
+
+#include <linux/types.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_fdt.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/bitmap.h>
+#include <linux/cpumask.h>
+#include <linux/mm.h>
+#include <linux/delay.h>
+#include <linux/libfdt.h>
+
+#include <asm/machdep.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/smp.h>
+#include <asm/irq.h>
+#include <asm/errno.h>
+#include <asm/xive.h>
+#include <asm/xive-regs.h>
+#include <asm/hvcall.h>
+#include <asm/svm.h>
+#include <asm/ultravisor.h>
+
+#include "xive-internal.h"
+
+static u32 xive_queue_shift;
+
+struct xive_irq_bitmap {
+	unsigned long		*bitmap;
+	unsigned int		base;
+	unsigned int		count;
+	spinlock_t		lock;
+	struct list_head	list;
+};
+
+static LIST_HEAD(xive_irq_bitmaps);
+
+static int __init xive_irq_bitmap_add(int base, int count)
+{
+	struct xive_irq_bitmap *xibm;
+
+	xibm = kzalloc(sizeof(*xibm), GFP_KERNEL);
+	if (!xibm)
+		return -ENOMEM;
+
+	spin_lock_init(&xibm->lock);
+	xibm->base = base;
+	xibm->count = count;
+	xibm->bitmap = bitmap_zalloc(xibm->count, GFP_KERNEL);
+	if (!xibm->bitmap) {
+		kfree(xibm);
+		return -ENOMEM;
+	}
+	list_add(&xibm->list, &xive_irq_bitmaps);
+
+	pr_info("Using IRQ range [%x-%x]", xibm->base,
+		xibm->base + xibm->count - 1);
+	return 0;
+}
+
+static void xive_irq_bitmap_remove_all(void)
+{
+	struct xive_irq_bitmap *xibm, *tmp;
+
+	list_for_each_entry_safe(xibm, tmp, &xive_irq_bitmaps, list) {
+		list_del(&xibm->list);
+		bitmap_free(xibm->bitmap);
+		kfree(xibm);
+	}
+}
+
+static int __xive_irq_bitmap_alloc(struct xive_irq_bitmap *xibm)
+{
+	int irq;
+
+	irq = find_first_zero_bit(xibm->bitmap, xibm->count);
+	if (irq != xibm->count) {
+		set_bit(irq, xibm->bitmap);
+		irq += xibm->base;
+	} else {
+		irq = -ENOMEM;
+	}
+
+	return irq;
+}
+
+static int xive_irq_bitmap_alloc(void)
+{
+	struct xive_irq_bitmap *xibm;
+	unsigned long flags;
+	int irq = -ENOENT;
+
+	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
+		spin_lock_irqsave(&xibm->lock, flags);
+		irq = __xive_irq_bitmap_alloc(xibm);
+		spin_unlock_irqrestore(&xibm->lock, flags);
+		if (irq >= 0)
+			break;
+	}
+	return irq;
+}
+
+static void xive_irq_bitmap_free(int irq)
+{
+	unsigned long flags;
+	struct xive_irq_bitmap *xibm;
+
+	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
+		if ((irq >= xibm->base) && (irq < xibm->base + xibm->count)) {
+			spin_lock_irqsave(&xibm->lock, flags);
+			clear_bit(irq - xibm->base, xibm->bitmap);
+			spin_unlock_irqrestore(&xibm->lock, flags);
+			break;
+		}
+	}
+}
+
+
+/* Based on the similar routines in RTAS */
+static unsigned int plpar_busy_delay_time(long rc)
+{
+	unsigned int ms = 0;
+
+	if (H_IS_LONG_BUSY(rc)) {
+		ms = get_longbusy_msecs(rc);
+	} else if (rc == H_BUSY) {
+		ms = 10; /* seems appropriate for XIVE hcalls */
+	}
+
+	return ms;
+}
+
+static unsigned int plpar_busy_delay(int rc)
+{
+	unsigned int ms;
+
+	ms = plpar_busy_delay_time(rc);
+	if (ms)
+		mdelay(ms);
+
+	return ms;
+}
+
+/*
+ * Note: this call has a partition wide scope and can take a while to
+ * complete. If it returns H_LONG_BUSY_* it should be retried
+ * periodically.
+ */
+static long plpar_int_reset(unsigned long flags)
+{
+	long rc;
+
+	do {
+		rc = plpar_hcall_norets(H_INT_RESET, flags);
+	} while (plpar_busy_delay(rc));
+
+	if (rc)
+		pr_err("H_INT_RESET failed %ld\n", rc);
+
+	return rc;
+}
+
+static long plpar_int_get_source_info(unsigned long flags,
+				      unsigned long lisn,
+				      unsigned long *src_flags,
+				      unsigned long *eoi_page,
+				      unsigned long *trig_page,
+				      unsigned long *esb_shift)
+{
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+	long rc;
+
+	do {
+		rc = plpar_hcall(H_INT_GET_SOURCE_INFO, retbuf, flags, lisn);
+	} while (plpar_busy_delay(rc));
+
+	if (rc) {
+		pr_err("H_INT_GET_SOURCE_INFO lisn=0x%lx failed %ld\n", lisn, rc);
+		return rc;
+	}
+
+	*src_flags = retbuf[0];
+	*eoi_page  = retbuf[1];
+	*trig_page = retbuf[2];
+	*esb_shift = retbuf[3];
+
+	pr_debug("H_INT_GET_SOURCE_INFO lisn=0x%lx flags=0x%lx eoi=0x%lx trig=0x%lx shift=0x%lx\n",
+		 lisn, retbuf[0], retbuf[1], retbuf[2], retbuf[3]);
+
+	return 0;
+}
+
+#define XIVE_SRC_SET_EISN (1ull << (63 - 62))
+#define XIVE_SRC_MASK     (1ull << (63 - 63)) /* unused */
+
+static long plpar_int_set_source_config(unsigned long flags,
+					unsigned long lisn,
+					unsigned long target,
+					unsigned long prio,
+					unsigned long sw_irq)
+{
+	long rc;
+
+
+	pr_debug("H_INT_SET_SOURCE_CONFIG flags=0x%lx lisn=0x%lx target=%ld prio=%ld sw_irq=%ld\n",
+		 flags, lisn, target, prio, sw_irq);
+
+
+	do {
+		rc = plpar_hcall_norets(H_INT_SET_SOURCE_CONFIG, flags, lisn,
+					target, prio, sw_irq);
+	} while (plpar_busy_delay(rc));
+
+	if (rc) {
+		pr_err("H_INT_SET_SOURCE_CONFIG lisn=0x%lx target=%ld prio=%ld failed %ld\n",
+		       lisn, target, prio, rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+static long plpar_int_get_source_config(unsigned long flags,
+					unsigned long lisn,
+					unsigned long *target,
+					unsigned long *prio,
+					unsigned long *sw_irq)
+{
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+	long rc;
+
+	pr_debug("H_INT_GET_SOURCE_CONFIG flags=0x%lx lisn=0x%lx\n", flags, lisn);
+
+	do {
+		rc = plpar_hcall(H_INT_GET_SOURCE_CONFIG, retbuf, flags, lisn,
+				 target, prio, sw_irq);
+	} while (plpar_busy_delay(rc));
+
+	if (rc) {
+		pr_err("H_INT_GET_SOURCE_CONFIG lisn=0x%lx failed %ld\n",
+		       lisn, rc);
+		return rc;
+	}
+
+	*target = retbuf[0];
+	*prio   = retbuf[1];
+	*sw_irq = retbuf[2];
+
+	pr_debug("H_INT_GET_SOURCE_CONFIG target=%ld prio=%ld sw_irq=%ld\n",
+		 retbuf[0], retbuf[1], retbuf[2]);
+
+	return 0;
+}
+
+static long plpar_int_get_queue_info(unsigned long flags,
+				     unsigned long target,
+				     unsigned long priority,
+				     unsigned long *esn_page,
+				     unsigned long *esn_size)
+{
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+	long rc;
+
+	do {
+		rc = plpar_hcall(H_INT_GET_QUEUE_INFO, retbuf, flags, target,
+				 priority);
+	} while (plpar_busy_delay(rc));
+
+	if (rc) {
+		pr_err("H_INT_GET_QUEUE_INFO cpu=%ld prio=%ld failed %ld\n",
+		       target, priority, rc);
+		return rc;
+	}
+
+	*esn_page = retbuf[0];
+	*esn_size = retbuf[1];
+
+	pr_debug("H_INT_GET_QUEUE_INFO cpu=%ld prio=%ld page=0x%lx size=0x%lx\n",
+		 target, priority, retbuf[0], retbuf[1]);
+
+	return 0;
+}
+
+#define XIVE_EQ_ALWAYS_NOTIFY (1ull << (63 - 63))
+
+static long plpar_int_set_queue_config(unsigned long flags,
+				       unsigned long target,
+				       unsigned long priority,
+				       unsigned long qpage,
+				       unsigned long qsize)
+{
+	long rc;
+
+	pr_debug("H_INT_SET_QUEUE_CONFIG flags=0x%lx target=%ld priority=0x%lx qpage=0x%lx qsize=0x%lx\n",
+		 flags,  target, priority, qpage, qsize);
+
+	do {
+		rc = plpar_hcall_norets(H_INT_SET_QUEUE_CONFIG, flags, target,
+					priority, qpage, qsize);
+	} while (plpar_busy_delay(rc));
+
+	if (rc) {
+		pr_err("H_INT_SET_QUEUE_CONFIG cpu=%ld prio=%ld qpage=0x%lx returned %ld\n",
+		       target, priority, qpage, rc);
+		return  rc;
+	}
+
+	return 0;
+}
+
+static long plpar_int_sync(unsigned long flags, unsigned long lisn)
+{
+	long rc;
+
+	do {
+		rc = plpar_hcall_norets(H_INT_SYNC, flags, lisn);
+	} while (plpar_busy_delay(rc));
+
+	if (rc) {
+		pr_err("H_INT_SYNC lisn=0x%lx returned %ld\n", lisn, rc);
+		return  rc;
+	}
+
+	return 0;
+}
+
+#define XIVE_ESB_FLAG_STORE (1ull << (63 - 63))
+
+static long plpar_int_esb(unsigned long flags,
+			  unsigned long lisn,
+			  unsigned long offset,
+			  unsigned long in_data,
+			  unsigned long *out_data)
+{
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+	long rc;
+
+	pr_debug("H_INT_ESB flags=0x%lx lisn=0x%lx offset=0x%lx in=0x%lx\n",
+		 flags,  lisn, offset, in_data);
+
+	do {
+		rc = plpar_hcall(H_INT_ESB, retbuf, flags, lisn, offset,
+				 in_data);
+	} while (plpar_busy_delay(rc));
+
+	if (rc) {
+		pr_err("H_INT_ESB lisn=0x%lx offset=0x%lx returned %ld\n",
+		       lisn, offset, rc);
+		return  rc;
+	}
+
+	*out_data = retbuf[0];
+
+	return 0;
+}
+
+static u64 xive_spapr_esb_rw(u32 lisn, u32 offset, u64 data, bool write)
+{
+	unsigned long read_data;
+	long rc;
+
+	rc = plpar_int_esb(write ? XIVE_ESB_FLAG_STORE : 0,
+			   lisn, offset, data, &read_data);
+	if (rc)
+		return -1;
+
+	return write ? 0 : read_data;
+}
+
+#define XIVE_SRC_H_INT_ESB     (1ull << (63 - 60))
+#define XIVE_SRC_LSI           (1ull << (63 - 61))
+#define XIVE_SRC_TRIGGER       (1ull << (63 - 62))
+#define XIVE_SRC_STORE_EOI     (1ull << (63 - 63))
+
+static int xive_spapr_populate_irq_data(u32 hw_irq, struct xive_irq_data *data)
+{
+	long rc;
+	unsigned long flags;
+	unsigned long eoi_page;
+	unsigned long trig_page;
+	unsigned long esb_shift;
+
+	memset(data, 0, sizeof(*data));
+
+	rc = plpar_int_get_source_info(0, hw_irq, &flags, &eoi_page, &trig_page,
+				       &esb_shift);
+	if (rc)
+		return  -EINVAL;
+
+	if (flags & XIVE_SRC_H_INT_ESB)
+		data->flags  |= XIVE_IRQ_FLAG_H_INT_ESB;
+	if (flags & XIVE_SRC_STORE_EOI)
+		data->flags  |= XIVE_IRQ_FLAG_STORE_EOI;
+	if (flags & XIVE_SRC_LSI)
+		data->flags  |= XIVE_IRQ_FLAG_LSI;
+	data->eoi_page  = eoi_page;
+	data->esb_shift = esb_shift;
+	data->trig_page = trig_page;
+
+	data->hw_irq = hw_irq;
+
+	/*
+	 * No chip-id for the sPAPR backend. This has an impact how we
+	 * pick a target. See xive_pick_irq_target().
+	 */
+	data->src_chip = XIVE_INVALID_CHIP_ID;
+
+	/*
+	 * When the H_INT_ESB flag is set, the H_INT_ESB hcall should
+	 * be used for interrupt management. Skip the remapping of the
+	 * ESB pages which are not available.
+	 */
+	if (data->flags & XIVE_IRQ_FLAG_H_INT_ESB)
+		return 0;
+
+	data->eoi_mmio = ioremap(data->eoi_page, 1u << data->esb_shift);
+	if (!data->eoi_mmio) {
+		pr_err("Failed to map EOI page for irq 0x%x\n", hw_irq);
+		return -ENOMEM;
+	}
+
+	/* Full function page supports trigger */
+	if (flags & XIVE_SRC_TRIGGER) {
+		data->trig_mmio = data->eoi_mmio;
+		return 0;
+	}
+
+	data->trig_mmio = ioremap(data->trig_page, 1u << data->esb_shift);
+	if (!data->trig_mmio) {
+		iounmap(data->eoi_mmio);
+		pr_err("Failed to map trigger page for irq 0x%x\n", hw_irq);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static int xive_spapr_configure_irq(u32 hw_irq, u32 target, u8 prio, u32 sw_irq)
+{
+	long rc;
+
+	rc = plpar_int_set_source_config(XIVE_SRC_SET_EISN, hw_irq, target,
+					 prio, sw_irq);
+
+	return rc == 0 ? 0 : -ENXIO;
+}
+
+static int xive_spapr_get_irq_config(u32 hw_irq, u32 *target, u8 *prio,
+				     u32 *sw_irq)
+{
+	long rc;
+	unsigned long h_target;
+	unsigned long h_prio;
+	unsigned long h_sw_irq;
+
+	rc = plpar_int_get_source_config(0, hw_irq, &h_target, &h_prio,
+					 &h_sw_irq);
+
+	*target = h_target;
+	*prio = h_prio;
+	*sw_irq = h_sw_irq;
+
+	return rc == 0 ? 0 : -ENXIO;
+}
+
+/* This can be called multiple time to change a queue configuration */
+static int xive_spapr_configure_queue(u32 target, struct xive_q *q, u8 prio,
+				   __be32 *qpage, u32 order)
+{
+	s64 rc = 0;
+	unsigned long esn_page;
+	unsigned long esn_size;
+	u64 flags, qpage_phys;
+
+	/* If there's an actual queue page, clean it */
+	if (order) {
+		if (WARN_ON(!qpage))
+			return -EINVAL;
+		qpage_phys = __pa(qpage);
+	} else {
+		qpage_phys = 0;
+	}
+
+	/* Initialize the rest of the fields */
+	q->msk = order ? ((1u << (order - 2)) - 1) : 0;
+	q->idx = 0;
+	q->toggle = 0;
+
+	rc = plpar_int_get_queue_info(0, target, prio, &esn_page, &esn_size);
+	if (rc) {
+		pr_err("Error %lld getting queue info CPU %d prio %d\n", rc,
+		       target, prio);
+		rc = -EIO;
+		goto fail;
+	}
+
+	/* TODO: add support for the notification page */
+	q->eoi_phys = esn_page;
+
+	/* Default is to always notify */
+	flags = XIVE_EQ_ALWAYS_NOTIFY;
+
+	/* Configure and enable the queue in HW */
+	rc = plpar_int_set_queue_config(flags, target, prio, qpage_phys, order);
+	if (rc) {
+		pr_err("Error %lld setting queue for CPU %d prio %d\n", rc,
+		       target, prio);
+		rc = -EIO;
+	} else {
+		q->qpage = qpage;
+		if (is_secure_guest())
+			uv_share_page(PHYS_PFN(qpage_phys),
+					1 << xive_alloc_order(order));
+	}
+fail:
+	return rc;
+}
+
+static int xive_spapr_setup_queue(unsigned int cpu, struct xive_cpu *xc,
+				  u8 prio)
+{
+	struct xive_q *q = &xc->queue[prio];
+	__be32 *qpage;
+
+	qpage = xive_queue_page_alloc(cpu, xive_queue_shift);
+	if (IS_ERR(qpage))
+		return PTR_ERR(qpage);
+
+	return xive_spapr_configure_queue(get_hard_smp_processor_id(cpu),
+					  q, prio, qpage, xive_queue_shift);
+}
+
+static void xive_spapr_cleanup_queue(unsigned int cpu, struct xive_cpu *xc,
+				  u8 prio)
+{
+	struct xive_q *q = &xc->queue[prio];
+	unsigned int alloc_order;
+	long rc;
+	int hw_cpu = get_hard_smp_processor_id(cpu);
+
+	rc = plpar_int_set_queue_config(0, hw_cpu, prio, 0, 0);
+	if (rc)
+		pr_err("Error %ld setting queue for CPU %d prio %d\n", rc,
+		       hw_cpu, prio);
+
+	alloc_order = xive_alloc_order(xive_queue_shift);
+	if (is_secure_guest())
+		uv_unshare_page(PHYS_PFN(__pa(q->qpage)), 1 << alloc_order);
+	free_pages((unsigned long)q->qpage, alloc_order);
+	q->qpage = NULL;
+}
+
+static bool xive_spapr_match(struct device_node *node)
+{
+	/* Ignore cascaded controllers for the moment */
+	return true;
+}
+
+#ifdef CONFIG_SMP
+static int xive_spapr_get_ipi(unsigned int cpu, struct xive_cpu *xc)
+{
+	int irq = xive_irq_bitmap_alloc();
+
+	if (irq < 0) {
+		pr_err("Failed to allocate IPI on CPU %d\n", cpu);
+		return -ENXIO;
+	}
+
+	xc->hw_ipi = irq;
+	return 0;
+}
+
+static void xive_spapr_put_ipi(unsigned int cpu, struct xive_cpu *xc)
+{
+	if (xc->hw_ipi == XIVE_BAD_IRQ)
+		return;
+
+	xive_irq_bitmap_free(xc->hw_ipi);
+	xc->hw_ipi = XIVE_BAD_IRQ;
+}
+#endif /* CONFIG_SMP */
+
+static void xive_spapr_shutdown(void)
+{
+	plpar_int_reset(0);
+}
+
+/*
+ * Perform an "ack" cycle on the current thread. Grab the pending
+ * active priorities and update the CPPR to the most favored one.
+ */
+static void xive_spapr_update_pending(struct xive_cpu *xc)
+{
+	u8 nsr, cppr;
+	u16 ack;
+
+	/*
+	 * Perform the "Acknowledge O/S to Register" cycle.
+	 *
+	 * Let's speedup the access to the TIMA using the raw I/O
+	 * accessor as we don't need the synchronisation routine of
+	 * the higher level ones
+	 */
+	ack = be16_to_cpu(__raw_readw(xive_tima + TM_SPC_ACK_OS_REG));
+
+	/* Synchronize subsequent queue accesses */
+	mb();
+
+	/*
+	 * Grab the CPPR and the "NSR" field which indicates the source
+	 * of the interrupt (if any)
+	 */
+	cppr = ack & 0xff;
+	nsr = ack >> 8;
+
+	if (nsr & TM_QW1_NSR_EO) {
+		if (cppr == 0xff)
+			return;
+		/* Mark the priority pending */
+		xc->pending_prio |= 1 << cppr;
+
+		/*
+		 * A new interrupt should never have a CPPR less favored
+		 * than our current one.
+		 */
+		if (cppr >= xc->cppr)
+			pr_err("CPU %d odd ack CPPR, got %d at %d\n",
+			       smp_processor_id(), cppr, xc->cppr);
+
+		/* Update our idea of what the CPPR is */
+		xc->cppr = cppr;
+	}
+}
+
+static void xive_spapr_setup_cpu(unsigned int cpu, struct xive_cpu *xc)
+{
+	/* Only some debug on the TIMA settings */
+	pr_debug("(HW value: %08x %08x %08x)\n",
+		 in_be32(xive_tima + TM_QW1_OS + TM_WORD0),
+		 in_be32(xive_tima + TM_QW1_OS + TM_WORD1),
+		 in_be32(xive_tima + TM_QW1_OS + TM_WORD2));
+}
+
+static void xive_spapr_teardown_cpu(unsigned int cpu, struct xive_cpu *xc)
+{
+	/* Nothing to do */;
+}
+
+static void xive_spapr_sync_source(u32 hw_irq)
+{
+	/* Specs are unclear on what this is doing */
+	plpar_int_sync(0, hw_irq);
+}
+
+static int xive_spapr_debug_show(struct seq_file *m, void *private)
+{
+	struct xive_irq_bitmap *xibm;
+	char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+
+	if (!buf)
+		return -ENOMEM;
+
+	list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
+		memset(buf, 0, PAGE_SIZE);
+		bitmap_print_to_pagebuf(true, buf, xibm->bitmap, xibm->count);
+		seq_printf(m, "bitmap #%d: %s", xibm->count, buf);
+	}
+	kfree(buf);
+
+	return 0;
+}
+
+static const struct xive_ops xive_spapr_ops = {
+	.populate_irq_data	= xive_spapr_populate_irq_data,
+	.configure_irq		= xive_spapr_configure_irq,
+	.get_irq_config		= xive_spapr_get_irq_config,
+	.setup_queue		= xive_spapr_setup_queue,
+	.cleanup_queue		= xive_spapr_cleanup_queue,
+	.match			= xive_spapr_match,
+	.shutdown		= xive_spapr_shutdown,
+	.update_pending		= xive_spapr_update_pending,
+	.setup_cpu		= xive_spapr_setup_cpu,
+	.teardown_cpu		= xive_spapr_teardown_cpu,
+	.sync_source		= xive_spapr_sync_source,
+	.esb_rw			= xive_spapr_esb_rw,
+#ifdef CONFIG_SMP
+	.get_ipi		= xive_spapr_get_ipi,
+	.put_ipi		= xive_spapr_put_ipi,
+	.debug_show		= xive_spapr_debug_show,
+#endif /* CONFIG_SMP */
+	.name			= "spapr",
+};
+
+/*
+ * get max priority from "/ibm,plat-res-int-priorities"
+ */
+static bool __init xive_get_max_prio(u8 *max_prio)
+{
+	struct device_node *rootdn;
+	const __be32 *reg;
+	u32 len;
+	int prio, found;
+
+	rootdn = of_find_node_by_path("/");
+	if (!rootdn) {
+		pr_err("not root node found !\n");
+		return false;
+	}
+
+	reg = of_get_property(rootdn, "ibm,plat-res-int-priorities", &len);
+	of_node_put(rootdn);
+	if (!reg) {
+		pr_err("Failed to read 'ibm,plat-res-int-priorities' property\n");
+		return false;
+	}
+
+	if (len % (2 * sizeof(u32)) != 0) {
+		pr_err("invalid 'ibm,plat-res-int-priorities' property\n");
+		return false;
+	}
+
+	/* HW supports priorities in the range [0-7] and 0xFF is a
+	 * wildcard priority used to mask. We scan the ranges reserved
+	 * by the hypervisor to find the lowest priority we can use.
+	 */
+	found = 0xFF;
+	for (prio = 0; prio < 8; prio++) {
+		int reserved = 0;
+		int i;
+
+		for (i = 0; i < len / (2 * sizeof(u32)); i++) {
+			int base  = be32_to_cpu(reg[2 * i]);
+			int range = be32_to_cpu(reg[2 * i + 1]);
+
+			if (prio >= base && prio < base + range)
+				reserved++;
+		}
+
+		if (!reserved)
+			found = prio;
+	}
+
+	if (found == 0xFF) {
+		pr_err("no valid priority found in 'ibm,plat-res-int-priorities'\n");
+		return false;
+	}
+
+	*max_prio = found;
+	return true;
+}
+
+static const u8 *__init get_vec5_feature(unsigned int index)
+{
+	unsigned long root, chosen;
+	int size;
+	const u8 *vec5;
+
+	root = of_get_flat_dt_root();
+	chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
+	if (chosen == -FDT_ERR_NOTFOUND)
+		return NULL;
+
+	vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size);
+	if (!vec5)
+		return NULL;
+
+	if (size <= index)
+		return NULL;
+
+	return vec5 + index;
+}
+
+static bool __init xive_spapr_disabled(void)
+{
+	const u8 *vec5_xive;
+
+	vec5_xive = get_vec5_feature(OV5_INDX(OV5_XIVE_SUPPORT));
+	if (vec5_xive) {
+		u8 val;
+
+		val = *vec5_xive & OV5_FEAT(OV5_XIVE_SUPPORT);
+		switch (val) {
+		case OV5_FEAT(OV5_XIVE_EITHER):
+		case OV5_FEAT(OV5_XIVE_LEGACY):
+			break;
+		case OV5_FEAT(OV5_XIVE_EXPLOIT):
+			/* Hypervisor only supports XIVE */
+			if (xive_cmdline_disabled)
+				pr_warn("WARNING: Ignoring cmdline option xive=off\n");
+			return false;
+		default:
+			pr_warn("%s: Unknown xive support option: 0x%x\n",
+				__func__, val);
+			break;
+		}
+	}
+
+	return xive_cmdline_disabled;
+}
+
+bool __init xive_spapr_init(void)
+{
+	struct device_node *np;
+	struct resource r;
+	void __iomem *tima;
+	struct property *prop;
+	u8 max_prio;
+	u32 val;
+	u32 len;
+	const __be32 *reg;
+	int i, err;
+
+	if (xive_spapr_disabled())
+		return false;
+
+	pr_devel("%s()\n", __func__);
+	np = of_find_compatible_node(NULL, NULL, "ibm,power-ivpe");
+	if (!np) {
+		pr_devel("not found !\n");
+		return false;
+	}
+	pr_devel("Found %s\n", np->full_name);
+
+	/* Resource 1 is the OS ring TIMA */
+	if (of_address_to_resource(np, 1, &r)) {
+		pr_err("Failed to get thread mgmnt area resource\n");
+		goto err_put;
+	}
+	tima = ioremap(r.start, resource_size(&r));
+	if (!tima) {
+		pr_err("Failed to map thread mgmnt area\n");
+		goto err_put;
+	}
+
+	if (!xive_get_max_prio(&max_prio))
+		goto err_unmap;
+
+	/* Feed the IRQ number allocator with the ranges given in the DT */
+	reg = of_get_property(np, "ibm,xive-lisn-ranges", &len);
+	if (!reg) {
+		pr_err("Failed to read 'ibm,xive-lisn-ranges' property\n");
+		goto err_unmap;
+	}
+
+	if (len % (2 * sizeof(u32)) != 0) {
+		pr_err("invalid 'ibm,xive-lisn-ranges' property\n");
+		goto err_unmap;
+	}
+
+	for (i = 0; i < len / (2 * sizeof(u32)); i++, reg += 2) {
+		err = xive_irq_bitmap_add(be32_to_cpu(reg[0]),
+					  be32_to_cpu(reg[1]));
+		if (err < 0)
+			goto err_mem_free;
+	}
+
+	/* Iterate the EQ sizes and pick one */
+	of_property_for_each_u32(np, "ibm,xive-eq-sizes", prop, reg, val) {
+		xive_queue_shift = val;
+		if (val == PAGE_SHIFT)
+			break;
+	}
+
+	/* Initialize XIVE core with our backend */
+	if (!xive_core_init(np, &xive_spapr_ops, tima, TM_QW1_OS, max_prio))
+		goto err_mem_free;
+
+	of_node_put(np);
+	pr_info("Using %dkB queues\n", 1 << (xive_queue_shift - 10));
+	return true;
+
+err_mem_free:
+	xive_irq_bitmap_remove_all();
+err_unmap:
+	iounmap(tima);
+err_put:
+	of_node_put(np);
+	return false;
+}
+
+machine_arch_initcall(pseries, xive_core_debug_init);