1 files changed, 317 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
new file mode 100644
index 000000000..bc97770a6
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
@@ -0,0 +1,317 @@
+/*
+ * This file implements an irqchip for OPAL events. Whenever there is
+ * an interrupt that is handled by OPAL we get passed a list of events
+ * that Linux needs to do something about. These basically look like
+ * interrupts to Linux so we implement an irqchip to handle them.
+ *
+ * Copyright Alistair Popple, IBM Corporation 2014.
+ *
+ * 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/bitops.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/of_irq.h>
+
+#include <asm/machdep.h>
+#include <asm/opal.h>
+
+#include "powernv.h"
+
+/* Maximum number of events supported by OPAL firmware */
+#define MAX_NUM_EVENTS 64
+
+struct opal_event_irqchip {
+	struct irq_chip irqchip;
+	struct irq_domain *domain;
+	unsigned long mask;
+};
+static struct opal_event_irqchip opal_event_irqchip;
+static u64 last_outstanding_events;
+static int opal_irq_count;
+static struct resource *opal_irqs;
+
+void opal_handle_events(void)
+{
+	__be64 events = 0;
+	u64 e;
+
+	e = READ_ONCE(last_outstanding_events) & opal_event_irqchip.mask;
+again:
+	while (e) {
+		int virq, hwirq;
+
+		hwirq = fls64(e) - 1;
+		e &= ~BIT_ULL(hwirq);
+
+		local_irq_disable();
+		virq = irq_find_mapping(opal_event_irqchip.domain, hwirq);
+		if (virq) {
+			irq_enter();
+			generic_handle_irq(virq);
+			irq_exit();
+		}
+		local_irq_enable();
+
+		cond_resched();
+	}
+	last_outstanding_events = 0;
+	if (opal_poll_events(&events) != OPAL_SUCCESS)
+		return;
+	e = be64_to_cpu(events) & opal_event_irqchip.mask;
+	if (e)
+		goto again;
+}
+
+bool opal_have_pending_events(void)
+{
+	if (last_outstanding_events & opal_event_irqchip.mask)
+		return true;
+	return false;
+}
+
+static void opal_event_mask(struct irq_data *d)
+{
+	clear_bit(d->hwirq, &opal_event_irqchip.mask);
+}
+
+static void opal_event_unmask(struct irq_data *d)
+{
+	set_bit(d->hwirq, &opal_event_irqchip.mask);
+	if (opal_have_pending_events())
+		opal_wake_poller();
+}
+
+static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
+{
+	/*
+	 * For now we only support level triggered events. The irq
+	 * handler will be called continuously until the event has
+	 * been cleared in OPAL.
+	 */
+	if (flow_type != IRQ_TYPE_LEVEL_HIGH)
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct opal_event_irqchip opal_event_irqchip = {
+	.irqchip = {
+		.name = "OPAL EVT",
+		.irq_mask = opal_event_mask,
+		.irq_unmask = opal_event_unmask,
+		.irq_set_type = opal_event_set_type,
+	},
+	.mask = 0,
+};
+
+static int opal_event_map(struct irq_domain *d, unsigned int irq,
+			irq_hw_number_t hwirq)
+{
+	irq_set_chip_data(irq, &opal_event_irqchip);
+	irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip,
+				handle_level_irq);
+
+	return 0;
+}
+
+static irqreturn_t opal_interrupt(int irq, void *data)
+{
+	__be64 events;
+
+	opal_handle_interrupt(virq_to_hw(irq), &events);
+	last_outstanding_events = be64_to_cpu(events);
+	if (opal_have_pending_events())
+		opal_wake_poller();
+
+	return IRQ_HANDLED;
+}
+
+static int opal_event_match(struct irq_domain *h, struct device_node *node,
+			    enum irq_domain_bus_token bus_token)
+{
+	return irq_domain_get_of_node(h) == node;
+}
+
+static int opal_event_xlate(struct irq_domain *h, struct device_node *np,
+			   const u32 *intspec, unsigned int intsize,
+			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
+{
+	*out_hwirq = intspec[0];
+	*out_flags = IRQ_TYPE_LEVEL_HIGH;
+
+	return 0;
+}
+
+static const struct irq_domain_ops opal_event_domain_ops = {
+	.match	= opal_event_match,
+	.map	= opal_event_map,
+	.xlate	= opal_event_xlate,
+};
+
+void opal_event_shutdown(void)
+{
+	unsigned int i;
+
+	/* First free interrupts, which will also mask them */
+	for (i = 0; i < opal_irq_count; i++) {
+		if (!opal_irqs || !opal_irqs[i].start)
+			continue;
+
+		if (in_interrupt() || irqs_disabled())
+			disable_irq_nosync(opal_irqs[i].start);
+		else
+			free_irq(opal_irqs[i].start, NULL);
+
+		opal_irqs[i].start = 0;
+	}
+}
+
+int __init opal_event_init(void)
+{
+	struct device_node *dn, *opal_node;
+	bool old_style = false;
+	int i, rc = 0;
+
+	opal_node = of_find_node_by_path("/ibm,opal");
+	if (!opal_node) {
+		pr_warn("opal: Node not found\n");
+		return -ENODEV;
+	}
+
+	/* If dn is NULL it means the domain won't be linked to a DT
+	 * node so therefore irq_of_parse_and_map(...) wont work. But
+	 * that shouldn't be problem because if we're running a
+	 * version of skiboot that doesn't have the dn then the
+	 * devices won't have the correct properties and will have to
+	 * fall back to the legacy method (opal_event_request(...))
+	 * anyway. */
+	dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event");
+	opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS,
+				&opal_event_domain_ops, &opal_event_irqchip);
+	of_node_put(dn);
+	if (!opal_event_irqchip.domain) {
+		pr_warn("opal: Unable to create irq domain\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	/* Look for new-style (standard) "interrupts" property */
+	opal_irq_count = of_irq_count(opal_node);
+
+	/* Absent ? Look for the old one */
+	if (opal_irq_count < 1) {
+		/* Get opal-interrupts property and names if present */
+		rc = of_property_count_u32_elems(opal_node, "opal-interrupts");
+		if (rc > 0)
+			opal_irq_count = rc;
+		old_style = true;
+	}
+
+	/* No interrupts ? Bail out */
+	if (!opal_irq_count)
+		goto out;
+
+	pr_debug("OPAL: Found %d interrupts reserved for OPAL using %s scheme\n",
+		 opal_irq_count, old_style ? "old" : "new");
+
+	/* Allocate an IRQ resources array */
+	opal_irqs = kcalloc(opal_irq_count, sizeof(struct resource), GFP_KERNEL);
+	if (WARN_ON(!opal_irqs)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	/* Build the resources array */
+	if (old_style) {
+		/* Old style "opal-interrupts" property */
+		for (i = 0; i < opal_irq_count; i++) {
+			struct resource *r = &opal_irqs[i];
+			const char *name = NULL;
+			u32 hw_irq;
+			int virq;
+
+			rc = of_property_read_u32_index(opal_node, "opal-interrupts",
+							i, &hw_irq);
+			if (WARN_ON(rc < 0)) {
+				opal_irq_count = i;
+				break;
+			}
+			of_property_read_string_index(opal_node, "opal-interrupts-names",
+						      i, &name);
+			virq = irq_create_mapping(NULL, hw_irq);
+			if (!virq) {
+				pr_warn("Failed to map OPAL irq 0x%x\n", hw_irq);
+				continue;
+			}
+			r->start = r->end = virq;
+			r->flags = IORESOURCE_IRQ | IRQ_TYPE_LEVEL_LOW;
+			r->name = name;
+		}
+	} else {
+		/* new style standard "interrupts" property */
+		rc = of_irq_to_resource_table(opal_node, opal_irqs, opal_irq_count);
+		if (WARN_ON(rc < 0)) {
+			opal_irq_count = 0;
+			kfree(opal_irqs);
+			goto out;
+		}
+		if (WARN_ON(rc < opal_irq_count))
+			opal_irq_count = rc;
+	}
+
+	/* Install interrupt handlers */
+	for (i = 0; i < opal_irq_count; i++) {
+		struct resource *r = &opal_irqs[i];
+		const char *name;
+
+		/* Prefix name */
+		if (r->name && strlen(r->name))
+			name = kasprintf(GFP_KERNEL, "opal-%s", r->name);
+		else
+			name = kasprintf(GFP_KERNEL, "opal");
+
+		/* Install interrupt handler */
+		rc = request_irq(r->start, opal_interrupt, r->flags & IRQD_TRIGGER_MASK,
+				 name, NULL);
+		if (rc) {
+			pr_warn("Error %d requesting OPAL irq %d\n", rc, (int)r->start);
+			continue;
+		}
+	}
+	rc = 0;
+ out:
+	of_node_put(opal_node);
+	return rc;
+}
+machine_arch_initcall(powernv, opal_event_init);
+
+/**
+ * opal_event_request(unsigned int opal_event_nr) - Request an event
+ * @opal_event_nr: the opal event number to request
+ *
+ * This routine can be used to find the linux virq number which can
+ * then be passed to request_irq to assign a handler for a particular
+ * opal event. This should only be used by legacy devices which don't
+ * have proper device tree bindings. Most devices should use
+ * irq_of_parse_and_map() instead.
+ */
+int opal_event_request(unsigned int opal_event_nr)
+{
+	if (WARN_ON_ONCE(!opal_event_irqchip.domain))
+		return 0;
+
+	return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
+}
+EXPORT_SYMBOL(opal_event_request);