File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
new file mode 100644
index 0000000..e505223
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
@@ -0,0 +1,266 @@
+/*
+ * 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/irq_work.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 unsigned int opal_irq_count;
+static unsigned int *opal_irqs;
+
+static void opal_handle_irq_work(struct irq_work *work);
+static u64 last_outstanding_events;
+static struct irq_work opal_event_irq_work = {
+ .func = opal_handle_irq_work,
+};
+
+void opal_handle_events(uint64_t events)
+{
+ int virq, hwirq = 0;
+ u64 mask = opal_event_irqchip.mask;
+
+ if (!in_irq() && (events & mask)) {
+ last_outstanding_events = events;
+ irq_work_queue(&opal_event_irq_work);
+ return;
+ }
+
+ while (events & mask) {
+ hwirq = fls64(events) - 1;
+ if (BIT_ULL(hwirq) & mask) {
+ virq = irq_find_mapping(opal_event_irqchip.domain,
+ hwirq);
+ if (virq)
+ generic_handle_irq(virq);
+ }
+ events &= ~BIT_ULL(hwirq);
+ }
+}
+
+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)
+{
+ __be64 events;
+
+ set_bit(d->hwirq, &opal_event_irqchip.mask);
+
+ opal_poll_events(&events);
+ last_outstanding_events = be64_to_cpu(events);
+
+ /*
+ * We can't just handle the events now with opal_handle_events().
+ * If we did we would deadlock when opal_event_unmask() is called from
+ * handle_level_irq() with the irq descriptor lock held, because
+ * calling opal_handle_events() would call generic_handle_irq() and
+ * then handle_level_irq() which would try to take the descriptor lock
+ * again. Instead queue the events for later.
+ */
+ if (last_outstanding_events & opal_event_irqchip.mask)
+ /* Need to retrigger the interrupt */
+ irq_work_queue(&opal_event_irq_work);
+}
+
+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);
+ opal_handle_events(be64_to_cpu(events));
+
+ return IRQ_HANDLED;
+}
+
+static void opal_handle_irq_work(struct irq_work *work)
+{
+ opal_handle_events(last_outstanding_events);
+}
+
+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[i])
+ free_irq(opal_irqs[i], NULL);
+ opal_irqs[i] = 0;
+ }
+}
+
+int __init opal_event_init(void)
+{
+ struct device_node *dn, *opal_node;
+ const __be32 *irqs;
+ int i, irqlen, 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;
+ }
+
+ /* Get interrupt property */
+ irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
+ opal_irq_count = irqs ? (irqlen / 4) : 0;
+ pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count);
+
+ /* Install interrupt handlers */
+ opal_irqs = kcalloc(opal_irq_count, sizeof(*opal_irqs), GFP_KERNEL);
+ for (i = 0; irqs && i < opal_irq_count; i++, irqs++) {
+ unsigned int irq, virq;
+
+ /* Get hardware and virtual IRQ */
+ irq = be32_to_cpup(irqs);
+ virq = irq_create_mapping(NULL, irq);
+ if (virq == NO_IRQ) {
+ pr_warn("Failed to map irq 0x%x\n", irq);
+ continue;
+ }
+
+ /* Install interrupt handler */
+ rc = request_irq(virq, opal_interrupt, 0, "opal", NULL);
+ if (rc) {
+ irq_dispose_mapping(virq);
+ pr_warn("Error %d requesting irq %d (0x%x)\n",
+ rc, virq, irq);
+ continue;
+ }
+
+ /* Cache IRQ */
+ opal_irqs[i] = virq;
+ }
+
+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 NO_IRQ;
+
+ return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
+}
+EXPORT_SYMBOL(opal_event_request);