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-rw-r--r--arch/powerpc/sysdev/xics/icp-opal.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/xics/icp-opal.c b/arch/powerpc/sysdev/xics/icp-opal.c
new file mode 100644
index 000000000..7fa520efc
--- /dev/null
+++ b/arch/powerpc/sysdev/xics/icp-opal.c
@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2016 IBM Corporation.
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+
+#include <asm/smp.h>
+#include <asm/irq.h>
+#include <asm/errno.h>
+#include <asm/xics.h>
+#include <asm/io.h>
+#include <asm/opal.h>
+#include <asm/kvm_ppc.h>
+
+static void icp_opal_teardown_cpu(void)
+{
+ int hw_cpu = hard_smp_processor_id();
+
+ /* Clear any pending IPI */
+ opal_int_set_mfrr(hw_cpu, 0xff);
+}
+
+static void icp_opal_flush_ipi(void)
+{
+ /*
+ * We take the ipi irq but and never return so we need to EOI the IPI,
+ * but want to leave our priority 0.
+ *
+ * Should we check all the other interrupts too?
+ * Should we be flagging idle loop instead?
+ * Or creating some task to be scheduled?
+ */
+ if (opal_int_eoi((0x00 << 24) | XICS_IPI) > 0)
+ force_external_irq_replay();
+}
+
+static unsigned int icp_opal_get_xirr(void)
+{
+ unsigned int kvm_xirr;
+ __be32 hw_xirr;
+ int64_t rc;
+
+ /* Handle an interrupt latched by KVM first */
+ kvm_xirr = kvmppc_get_xics_latch();
+ if (kvm_xirr)
+ return kvm_xirr;
+
+ /* Then ask OPAL */
+ rc = opal_int_get_xirr(&hw_xirr, false);
+ if (rc < 0)
+ return 0;
+ return be32_to_cpu(hw_xirr);
+}
+
+static unsigned int icp_opal_get_irq(void)
+{
+ unsigned int xirr;
+ unsigned int vec;
+ unsigned int irq;
+
+ xirr = icp_opal_get_xirr();
+ vec = xirr & 0x00ffffff;
+ if (vec == XICS_IRQ_SPURIOUS)
+ return 0;
+
+ irq = irq_find_mapping(xics_host, vec);
+ if (likely(irq)) {
+ xics_push_cppr(vec);
+ return irq;
+ }
+
+ /* We don't have a linux mapping, so have rtas mask it. */
+ xics_mask_unknown_vec(vec);
+
+ /* We might learn about it later, so EOI it */
+ if (opal_int_eoi(xirr) > 0)
+ force_external_irq_replay();
+
+ return 0;
+}
+
+static void icp_opal_set_cpu_priority(unsigned char cppr)
+{
+ /*
+ * Here be dragons. The caller has asked to allow only IPI's and not
+ * external interrupts. But OPAL XIVE doesn't support that. So instead
+ * of allowing no interrupts allow all. That's still not right, but
+ * currently the only caller who does this is xics_migrate_irqs_away()
+ * and it works in that case.
+ */
+ if (cppr >= DEFAULT_PRIORITY)
+ cppr = LOWEST_PRIORITY;
+
+ xics_set_base_cppr(cppr);
+ opal_int_set_cppr(cppr);
+ iosync();
+}
+
+static void icp_opal_eoi(struct irq_data *d)
+{
+ unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
+ int64_t rc;
+
+ iosync();
+ rc = opal_int_eoi((xics_pop_cppr() << 24) | hw_irq);
+
+ /*
+ * EOI tells us whether there are more interrupts to fetch.
+ *
+ * Some HW implementations might not be able to send us another
+ * external interrupt in that case, so we force a replay.
+ */
+ if (rc > 0)
+ force_external_irq_replay();
+}
+
+#ifdef CONFIG_SMP
+
+static void icp_opal_cause_ipi(int cpu)
+{
+ int hw_cpu = get_hard_smp_processor_id(cpu);
+
+ kvmppc_set_host_ipi(cpu);
+ opal_int_set_mfrr(hw_cpu, IPI_PRIORITY);
+}
+
+static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id)
+{
+ int cpu = smp_processor_id();
+
+ kvmppc_clear_host_ipi(cpu);
+ opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff);
+
+ return smp_ipi_demux();
+}
+
+/*
+ * Called when an interrupt is received on an off-line CPU to
+ * clear the interrupt, so that the CPU can go back to nap mode.
+ */
+void icp_opal_flush_interrupt(void)
+{
+ unsigned int xirr;
+ unsigned int vec;
+
+ do {
+ xirr = icp_opal_get_xirr();
+ vec = xirr & 0x00ffffff;
+ if (vec == XICS_IRQ_SPURIOUS)
+ break;
+ if (vec == XICS_IPI) {
+ /* Clear pending IPI */
+ int cpu = smp_processor_id();
+ kvmppc_clear_host_ipi(cpu);
+ opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff);
+ } else {
+ pr_err("XICS: hw interrupt 0x%x to offline cpu, "
+ "disabling\n", vec);
+ xics_mask_unknown_vec(vec);
+ }
+
+ /* EOI the interrupt */
+ } while (opal_int_eoi(xirr) > 0);
+}
+
+#endif /* CONFIG_SMP */
+
+static const struct icp_ops icp_opal_ops = {
+ .get_irq = icp_opal_get_irq,
+ .eoi = icp_opal_eoi,
+ .set_priority = icp_opal_set_cpu_priority,
+ .teardown_cpu = icp_opal_teardown_cpu,
+ .flush_ipi = icp_opal_flush_ipi,
+#ifdef CONFIG_SMP
+ .ipi_action = icp_opal_ipi_action,
+ .cause_ipi = icp_opal_cause_ipi,
+#endif
+};
+
+int icp_opal_init(void)
+{
+ struct device_node *np;
+
+ np = of_find_compatible_node(NULL, NULL, "ibm,opal-intc");
+ if (!np)
+ return -ENODEV;
+
+ icp_ops = &icp_opal_ops;
+
+ printk("XICS: Using OPAL ICP fallbacks\n");
+
+ of_node_put(np);
+ return 0;
+}
+