1 files changed, 148 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-loongarch-cpu.c b/drivers/irqchip/irq-loongarch-cpu.c
new file mode 100644
index 000000000000..327f3ab62c03
--- /dev/null
+++ b/drivers/irqchip/irq-loongarch-cpu.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+
+#include <asm/loongarch.h>
+#include <asm/setup.h>
+
+static struct irq_domain *irq_domain;
+struct fwnode_handle *cpuintc_handle;
+
+static u32 lpic_gsi_to_irq(u32 gsi)
+{
+	/* Only pch irqdomain transferring is required for LoongArch. */
+	if (gsi >= GSI_MIN_PCH_IRQ && gsi <= GSI_MAX_PCH_IRQ)
+		return acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
+
+	return 0;
+}
+
+static struct fwnode_handle *lpic_get_gsi_domain_id(u32 gsi)
+{
+	int id;
+	struct fwnode_handle *domain_handle = NULL;
+
+	switch (gsi) {
+	case GSI_MIN_CPU_IRQ ... GSI_MAX_CPU_IRQ:
+		if (liointc_handle)
+			domain_handle = liointc_handle;
+		break;
+
+	case GSI_MIN_LPC_IRQ ... GSI_MAX_LPC_IRQ:
+		if (pch_lpc_handle)
+			domain_handle = pch_lpc_handle;
+		break;
+
+	case GSI_MIN_PCH_IRQ ... GSI_MAX_PCH_IRQ:
+		id = find_pch_pic(gsi);
+		if (id >= 0 && pch_pic_handle[id])
+			domain_handle = pch_pic_handle[id];
+		break;
+	}
+
+	return domain_handle;
+}
+
+static void mask_loongarch_irq(struct irq_data *d)
+{
+	clear_csr_ecfg(ECFGF(d->hwirq));
+}
+
+static void unmask_loongarch_irq(struct irq_data *d)
+{
+	set_csr_ecfg(ECFGF(d->hwirq));
+}
+
+static struct irq_chip cpu_irq_controller = {
+	.name		= "CPUINTC",
+	.irq_mask	= mask_loongarch_irq,
+	.irq_unmask	= unmask_loongarch_irq,
+};
+
+static void handle_cpu_irq(struct pt_regs *regs)
+{
+	int hwirq;
+	unsigned int estat = read_csr_estat() & CSR_ESTAT_IS;
+
+	while ((hwirq = ffs(estat))) {
+		estat &= ~BIT(hwirq - 1);
+		generic_handle_domain_irq(irq_domain, hwirq - 1);
+	}
+}
+
+static int loongarch_cpu_intc_map(struct irq_domain *d, unsigned int irq,
+			     irq_hw_number_t hwirq)
+{
+	irq_set_noprobe(irq);
+	irq_set_chip_and_handler(irq, &cpu_irq_controller, handle_percpu_irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops loongarch_cpu_intc_irq_domain_ops = {
+	.map = loongarch_cpu_intc_map,
+	.xlate = irq_domain_xlate_onecell,
+};
+
+static int __init
+liointc_parse_madt(union acpi_subtable_headers *header,
+		       const unsigned long end)
+{
+	struct acpi_madt_lio_pic *liointc_entry = (struct acpi_madt_lio_pic *)header;
+
+	return liointc_acpi_init(irq_domain, liointc_entry);
+}
+
+static int __init
+eiointc_parse_madt(union acpi_subtable_headers *header,
+		       const unsigned long end)
+{
+	struct acpi_madt_eio_pic *eiointc_entry = (struct acpi_madt_eio_pic *)header;
+
+	return eiointc_acpi_init(irq_domain, eiointc_entry);
+}
+
+static int __init acpi_cascade_irqdomain_init(void)
+{
+	acpi_table_parse_madt(ACPI_MADT_TYPE_LIO_PIC,
+			      liointc_parse_madt, 0);
+	acpi_table_parse_madt(ACPI_MADT_TYPE_EIO_PIC,
+			      eiointc_parse_madt, 0);
+	return 0;
+}
+
+static int __init cpuintc_acpi_init(union acpi_subtable_headers *header,
+				   const unsigned long end)
+{
+	if (irq_domain)
+		return 0;
+
+	/* Mask interrupts. */
+	clear_csr_ecfg(ECFG0_IM);
+	clear_csr_estat(ESTATF_IP);
+
+	cpuintc_handle = irq_domain_alloc_fwnode(NULL);
+	irq_domain = irq_domain_create_linear(cpuintc_handle, EXCCODE_INT_NUM,
+					&loongarch_cpu_intc_irq_domain_ops, NULL);
+
+	if (!irq_domain)
+		panic("Failed to add irqdomain for LoongArch CPU");
+
+	set_handle_irq(&handle_cpu_irq);
+	acpi_set_irq_model(ACPI_IRQ_MODEL_LPIC, lpic_get_gsi_domain_id);
+	acpi_set_gsi_to_irq_fallback(lpic_gsi_to_irq);
+	acpi_cascade_irqdomain_init();
+
+	return 0;
+}
+
+IRQCHIP_ACPI_DECLARE(cpuintc_v1, ACPI_MADT_TYPE_CORE_PIC,
+		NULL, ACPI_MADT_CORE_PIC_VERSION_V1, cpuintc_acpi_init);