1 files changed, 286 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-mips-cpu.c b/drivers/irqchip/irq-mips-cpu.c
new file mode 100644
index 000000000..0bbb0b2d0
--- /dev/null
+++ b/drivers/irqchip/irq-mips-cpu.c
@@ -0,0 +1,286 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2001 MontaVista Software Inc.
+ * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
+ *
+ * Copyright (C) 2001 Ralf Baechle
+ * Copyright (C) 2005  MIPS Technologies, Inc.	All rights reserved.
+ *	Author: Maciej W. Rozycki <macro@mips.com>
+ *
+ * This file define the irq handler for MIPS CPU interrupts.
+ */
+
+/*
+ * Almost all MIPS CPUs define 8 interrupt sources.  They are typically
+ * level triggered (i.e., cannot be cleared from CPU; must be cleared from
+ * device).
+ *
+ * The first two are software interrupts (i.e. not exposed as pins) which
+ * may be used for IPIs in multi-threaded single-core systems.
+ *
+ * The last one is usually the CPU timer interrupt if the counter register
+ * is present, or for old CPUs with an external FPU by convention it's the
+ * FPU exception interrupt.
+ */
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+
+#include <asm/irq_cpu.h>
+#include <asm/mipsregs.h>
+#include <asm/mipsmtregs.h>
+#include <asm/setup.h>
+
+static struct irq_domain *irq_domain;
+static struct irq_domain *ipi_domain;
+
+static inline void unmask_mips_irq(struct irq_data *d)
+{
+	set_c0_status(IE_SW0 << d->hwirq);
+	irq_enable_hazard();
+}
+
+static inline void mask_mips_irq(struct irq_data *d)
+{
+	clear_c0_status(IE_SW0 << d->hwirq);
+	irq_disable_hazard();
+}
+
+static struct irq_chip mips_cpu_irq_controller = {
+	.name		= "MIPS",
+	.irq_ack	= mask_mips_irq,
+	.irq_mask	= mask_mips_irq,
+	.irq_mask_ack	= mask_mips_irq,
+	.irq_unmask	= unmask_mips_irq,
+	.irq_eoi	= unmask_mips_irq,
+	.irq_disable	= mask_mips_irq,
+	.irq_enable	= unmask_mips_irq,
+};
+
+/*
+ * Basically the same as above but taking care of all the MT stuff
+ */
+
+static unsigned int mips_mt_cpu_irq_startup(struct irq_data *d)
+{
+	unsigned int vpflags = dvpe();
+
+	clear_c0_cause(C_SW0 << d->hwirq);
+	evpe(vpflags);
+	unmask_mips_irq(d);
+	return 0;
+}
+
+/*
+ * While we ack the interrupt interrupts are disabled and thus we don't need
+ * to deal with concurrency issues.  Same for mips_cpu_irq_end.
+ */
+static void mips_mt_cpu_irq_ack(struct irq_data *d)
+{
+	unsigned int vpflags = dvpe();
+	clear_c0_cause(C_SW0 << d->hwirq);
+	evpe(vpflags);
+	mask_mips_irq(d);
+}
+
+#ifdef CONFIG_GENERIC_IRQ_IPI
+
+static void mips_mt_send_ipi(struct irq_data *d, unsigned int cpu)
+{
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	unsigned long flags;
+	int vpflags;
+
+	local_irq_save(flags);
+
+	/* We can only send IPIs to VPEs within the local core */
+	WARN_ON(!cpus_are_siblings(smp_processor_id(), cpu));
+
+	vpflags = dvpe();
+	settc(cpu_vpe_id(&cpu_data[cpu]));
+	write_vpe_c0_cause(read_vpe_c0_cause() | (C_SW0 << hwirq));
+	evpe(vpflags);
+
+	local_irq_restore(flags);
+}
+
+#endif /* CONFIG_GENERIC_IRQ_IPI */
+
+static struct irq_chip mips_mt_cpu_irq_controller = {
+	.name		= "MIPS",
+	.irq_startup	= mips_mt_cpu_irq_startup,
+	.irq_ack	= mips_mt_cpu_irq_ack,
+	.irq_mask	= mask_mips_irq,
+	.irq_mask_ack	= mips_mt_cpu_irq_ack,
+	.irq_unmask	= unmask_mips_irq,
+	.irq_eoi	= unmask_mips_irq,
+	.irq_disable	= mask_mips_irq,
+	.irq_enable	= unmask_mips_irq,
+#ifdef CONFIG_GENERIC_IRQ_IPI
+	.ipi_send_single = mips_mt_send_ipi,
+#endif
+};
+
+asmlinkage void __weak plat_irq_dispatch(void)
+{
+	unsigned long pending = read_c0_cause() & read_c0_status() & ST0_IM;
+	unsigned int virq;
+	int irq;
+
+	if (!pending) {
+		spurious_interrupt();
+		return;
+	}
+
+	pending >>= CAUSEB_IP;
+	while (pending) {
+		irq = fls(pending) - 1;
+		if (IS_ENABLED(CONFIG_GENERIC_IRQ_IPI) && irq < 2)
+			virq = irq_linear_revmap(ipi_domain, irq);
+		else
+			virq = irq_linear_revmap(irq_domain, irq);
+		do_IRQ(virq);
+		pending &= ~BIT(irq);
+	}
+}
+
+static int mips_cpu_intc_map(struct irq_domain *d, unsigned int irq,
+			     irq_hw_number_t hw)
+{
+	struct irq_chip *chip;
+
+	if (hw < 2 && cpu_has_mipsmt) {
+		/* Software interrupts are used for MT/CMT IPI */
+		chip = &mips_mt_cpu_irq_controller;
+	} else {
+		chip = &mips_cpu_irq_controller;
+	}
+
+	if (cpu_has_vint)
+		set_vi_handler(hw, plat_irq_dispatch);
+
+	irq_set_chip_and_handler(irq, chip, handle_percpu_irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops mips_cpu_intc_irq_domain_ops = {
+	.map = mips_cpu_intc_map,
+	.xlate = irq_domain_xlate_onecell,
+};
+
+#ifdef CONFIG_GENERIC_IRQ_IPI
+
+struct cpu_ipi_domain_state {
+	DECLARE_BITMAP(allocated, 2);
+};
+
+static int mips_cpu_ipi_alloc(struct irq_domain *domain, unsigned int virq,
+			      unsigned int nr_irqs, void *arg)
+{
+	struct cpu_ipi_domain_state *state = domain->host_data;
+	unsigned int i, hwirq;
+	int ret;
+
+	for (i = 0; i < nr_irqs; i++) {
+		hwirq = find_first_zero_bit(state->allocated, 2);
+		if (hwirq == 2)
+			return -EBUSY;
+		bitmap_set(state->allocated, hwirq, 1);
+
+		ret = irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq,
+						    &mips_mt_cpu_irq_controller,
+						    NULL);
+		if (ret)
+			return ret;
+
+		ret = irq_domain_set_hwirq_and_chip(domain->parent, virq + i, hwirq,
+						    &mips_mt_cpu_irq_controller,
+						    NULL);
+
+		if (ret)
+			return ret;
+
+		ret = irq_set_irq_type(virq + i, IRQ_TYPE_LEVEL_HIGH);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mips_cpu_ipi_match(struct irq_domain *d, struct device_node *node,
+			      enum irq_domain_bus_token bus_token)
+{
+	bool is_ipi;
+
+	switch (bus_token) {
+	case DOMAIN_BUS_IPI:
+		is_ipi = d->bus_token == bus_token;
+		return (!node || (to_of_node(d->fwnode) == node)) && is_ipi;
+	default:
+		return 0;
+	}
+}
+
+static const struct irq_domain_ops mips_cpu_ipi_chip_ops = {
+	.alloc	= mips_cpu_ipi_alloc,
+	.match	= mips_cpu_ipi_match,
+};
+
+static void mips_cpu_register_ipi_domain(struct device_node *of_node)
+{
+	struct cpu_ipi_domain_state *ipi_domain_state;
+
+	ipi_domain_state = kzalloc(sizeof(*ipi_domain_state), GFP_KERNEL);
+	ipi_domain = irq_domain_add_hierarchy(irq_domain,
+					      IRQ_DOMAIN_FLAG_IPI_SINGLE,
+					      2, of_node,
+					      &mips_cpu_ipi_chip_ops,
+					      ipi_domain_state);
+	if (!ipi_domain)
+		panic("Failed to add MIPS CPU IPI domain");
+	irq_domain_update_bus_token(ipi_domain, DOMAIN_BUS_IPI);
+}
+
+#else /* !CONFIG_GENERIC_IRQ_IPI */
+
+static inline void mips_cpu_register_ipi_domain(struct device_node *of_node) {}
+
+#endif /* !CONFIG_GENERIC_IRQ_IPI */
+
+static void __init __mips_cpu_irq_init(struct device_node *of_node)
+{
+	/* Mask interrupts. */
+	clear_c0_status(ST0_IM);
+	clear_c0_cause(CAUSEF_IP);
+
+	irq_domain = irq_domain_add_legacy(of_node, 8, MIPS_CPU_IRQ_BASE, 0,
+					   &mips_cpu_intc_irq_domain_ops,
+					   NULL);
+	if (!irq_domain)
+		panic("Failed to add irqdomain for MIPS CPU");
+
+	/*
+	 * Only proceed to register the software interrupt IPI implementation
+	 * for CPUs which implement the MIPS MT (multi-threading) ASE.
+	 */
+	if (cpu_has_mipsmt)
+		mips_cpu_register_ipi_domain(of_node);
+}
+
+void __init mips_cpu_irq_init(void)
+{
+	__mips_cpu_irq_init(NULL);
+}
+
+int __init mips_cpu_irq_of_init(struct device_node *of_node,
+				struct device_node *parent)
+{
+	__mips_cpu_irq_init(of_node);
+	return 0;
+}
+IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);