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+/*
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+ * This file implements an irqchip for OPAL events. Whenever there is
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+ * an interrupt that is handled by OPAL we get passed a list of events
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+ * that Linux needs to do something about. These basically look like
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+ * interrupts to Linux so we implement an irqchip to handle them.
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+ *
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+ * Copyright Alistair Popple, IBM Corporation 2014.
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+ *
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+ * This program is free software; you can redistribute it and/or modify it
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+ * under the terms of the GNU General Public License as published by the
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+ * Free Software Foundation; either version 2 of the License, or (at your
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+ * option) any later version.
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+ */
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+#include <linux/bitops.h>
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+#include <linux/irq.h>
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+#include <linux/irqchip.h>
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+#include <linux/irqdomain.h>
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+#include <linux/interrupt.h>
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+#include <linux/module.h>
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+#include <linux/of.h>
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+#include <linux/platform_device.h>
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+#include <linux/kthread.h>
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+#include <linux/delay.h>
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+#include <linux/slab.h>
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+#include <linux/irq_work.h>
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+
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+#include <asm/machdep.h>
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+#include <asm/opal.h>
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+
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+#include "powernv.h"
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+
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+/* Maximum number of events supported by OPAL firmware */
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+#define MAX_NUM_EVENTS 64
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+
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+struct opal_event_irqchip {
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+ struct irq_chip irqchip;
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+ struct irq_domain *domain;
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+ unsigned long mask;
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+};
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+static struct opal_event_irqchip opal_event_irqchip;
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+
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+static unsigned int opal_irq_count;
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+static unsigned int *opal_irqs;
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+
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+static void opal_handle_irq_work(struct irq_work *work);
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+static __be64 last_outstanding_events;
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+static struct irq_work opal_event_irq_work = {
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+ .func = opal_handle_irq_work,
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+};
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+
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+static void opal_event_mask(struct irq_data *d)
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+{
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+ clear_bit(d->hwirq, &opal_event_irqchip.mask);
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+}
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+
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+static void opal_event_unmask(struct irq_data *d)
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+{
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+ set_bit(d->hwirq, &opal_event_irqchip.mask);
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+
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+ opal_poll_events(&last_outstanding_events);
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+ if (last_outstanding_events & opal_event_irqchip.mask)
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+ /* Need to retrigger the interrupt */
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+ irq_work_queue(&opal_event_irq_work);
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+}
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+
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+static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
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+{
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+ /*
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+ * For now we only support level triggered events. The irq
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+ * handler will be called continuously until the event has
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+ * been cleared in OPAL.
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+ */
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+ if (flow_type != IRQ_TYPE_LEVEL_HIGH)
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+ return -EINVAL;
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+
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+ return 0;
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+}
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+
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+static struct opal_event_irqchip opal_event_irqchip = {
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+ .irqchip = {
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+ .name = "OPAL EVT",
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+ .irq_mask = opal_event_mask,
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+ .irq_unmask = opal_event_unmask,
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+ .irq_set_type = opal_event_set_type,
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+ },
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+ .mask = 0,
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+};
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+
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+static int opal_event_map(struct irq_domain *d, unsigned int irq,
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+ irq_hw_number_t hwirq)
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+{
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+ irq_set_chip_data(irq, &opal_event_irqchip);
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+ irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip,
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+ handle_level_irq);
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+
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+ return 0;
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+}
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+
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+void opal_handle_events(uint64_t events)
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+{
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+ int virq, hwirq = 0;
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+ u64 mask = opal_event_irqchip.mask;
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+ u64 notifier_mask = 0;
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+
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+ if (!in_irq() && (events & mask)) {
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+ last_outstanding_events = events;
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+ irq_work_queue(&opal_event_irq_work);
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+ return;
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+ }
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+
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+ while (events) {
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+ hwirq = fls64(events) - 1;
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+ virq = irq_find_mapping(opal_event_irqchip.domain,
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+ hwirq);
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+ if (virq) {
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+ if (BIT_ULL(hwirq) & mask)
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+ generic_handle_irq(virq);
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+ } else
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+ notifier_mask |= BIT_ULL(hwirq);
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+ events &= ~BIT_ULL(hwirq);
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+ }
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+
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+ opal_do_notifier(notifier_mask);
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+}
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+
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+static irqreturn_t opal_interrupt(int irq, void *data)
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+{
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+ __be64 events;
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+
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+ opal_handle_interrupt(virq_to_hw(irq), &events);
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+ opal_handle_events(be64_to_cpu(events));
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+
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+ return IRQ_HANDLED;
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+}
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+
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+static void opal_handle_irq_work(struct irq_work *work)
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+{
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+ opal_handle_events(be64_to_cpu(last_outstanding_events));
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+}
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+
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+static int opal_event_match(struct irq_domain *h, struct device_node *node)
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+{
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+ return h->of_node == node;
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+}
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+
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+static int opal_event_xlate(struct irq_domain *h, struct device_node *np,
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+ const u32 *intspec, unsigned int intsize,
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+ irq_hw_number_t *out_hwirq, unsigned int *out_flags)
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+{
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+ *out_hwirq = intspec[0];
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+ *out_flags = IRQ_TYPE_LEVEL_HIGH;
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+
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+ return 0;
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+}
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+
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+static const struct irq_domain_ops opal_event_domain_ops = {
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+ .match = opal_event_match,
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+ .map = opal_event_map,
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+ .xlate = opal_event_xlate,
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+};
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+
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+void opal_event_shutdown(void)
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+{
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+ unsigned int i;
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+
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+ /* First free interrupts, which will also mask them */
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+ for (i = 0; i < opal_irq_count; i++) {
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+ if (opal_irqs[i])
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+ free_irq(opal_irqs[i], NULL);
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+ opal_irqs[i] = 0;
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+ }
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+}
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+
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+int __init opal_event_init(void)
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+{
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+ struct device_node *dn, *opal_node;
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+ const __be32 *irqs;
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+ int i, irqlen, rc = 0;
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+
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+ opal_node = of_find_node_by_path("/ibm,opal");
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+ if (!opal_node) {
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+ pr_warn("opal: Node not found\n");
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+ return -ENODEV;
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+ }
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+
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+ /* If dn is NULL it means the domain won't be linked to a DT
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+ * node so therefore irq_of_parse_and_map(...) wont work. But
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+ * that shouldn't be problem because if we're running a
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+ * version of skiboot that doesn't have the dn then the
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+ * devices won't have the correct properties and will have to
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+ * fall back to the legacy method (opal_event_request(...))
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+ * anyway. */
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+ dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event");
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+ opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS,
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+ &opal_event_domain_ops, &opal_event_irqchip);
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+ of_node_put(dn);
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+ if (!opal_event_irqchip.domain) {
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+ pr_warn("opal: Unable to create irq domain\n");
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+ rc = -ENOMEM;
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+ goto out;
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+ }
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+
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+ /* Get interrupt property */
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+ irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
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+ opal_irq_count = irqs ? (irqlen / 4) : 0;
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+ pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count);
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+
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+ /* Install interrupt handlers */
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+ opal_irqs = kcalloc(opal_irq_count, sizeof(*opal_irqs), GFP_KERNEL);
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+ for (i = 0; irqs && i < opal_irq_count; i++, irqs++) {
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+ unsigned int irq, virq;
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+
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+ /* Get hardware and virtual IRQ */
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+ irq = be32_to_cpup(irqs);
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+ virq = irq_create_mapping(NULL, irq);
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+ if (virq == NO_IRQ) {
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+ pr_warn("Failed to map irq 0x%x\n", irq);
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+ continue;
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+ }
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+
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+ /* Install interrupt handler */
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+ rc = request_irq(virq, opal_interrupt, 0, "opal", NULL);
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+ if (rc) {
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+ irq_dispose_mapping(virq);
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+ pr_warn("Error %d requesting irq %d (0x%x)\n",
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+ rc, virq, irq);
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+ continue;
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+ }
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+
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+ /* Cache IRQ */
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+ opal_irqs[i] = virq;
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+ }
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+
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+out:
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+ of_node_put(opal_node);
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+ return rc;
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+}
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+
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+/**
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+ * opal_event_request(unsigned int opal_event_nr) - Request an event
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+ * @opal_event_nr: the opal event number to request
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+ *
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+ * This routine can be used to find the linux virq number which can
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+ * then be passed to request_irq to assign a handler for a particular
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+ * opal event. This should only be used by legacy devices which don't
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+ * have proper device tree bindings. Most devices should use
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+ * irq_of_parse_and_map() instead.
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+ */
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+int opal_event_request(unsigned int opal_event_nr)
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+{
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+ return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
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+}
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+EXPORT_SYMBOL(opal_event_request);
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Alistair Popple