LoongArch: Add exception/interrupt handling

Add the exception and interrupt handling machanism for basic LoongArch
support.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 77 insertions, 0 deletions

diff --git a/arch/loongarch/kernel/irq.c b/arch/loongarch/kernel/irq.c
new file mode 100644
index 000000000000..9bd07edf0bce
--- /dev/null
+++ b/arch/loongarch/kernel/irq.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/atomic.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irqchip.h>
+#include <linux/kernel_stat.h>
+#include <linux/proc_fs.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+
+#include <asm/irq.h>
+#include <asm/loongson.h>
+#include <asm/setup.h>
+
+DEFINE_PER_CPU(unsigned long, irq_stack);
+
+struct irq_domain *cpu_domain;
+struct irq_domain *liointc_domain;
+struct irq_domain *pch_lpc_domain;
+struct irq_domain *pch_msi_domain[MAX_IO_PICS];
+struct irq_domain *pch_pic_domain[MAX_IO_PICS];
+
+/*
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves.
+ */
+void ack_bad_irq(unsigned int irq)
+{
+	pr_warn("Unexpected IRQ # %d\n", irq);
+}
+
+atomic_t irq_err_count;
+
+asmlinkage void spurious_interrupt(void)
+{
+	atomic_inc(&irq_err_count);
+}
+
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
+	return 0;
+}
+
+void __init init_IRQ(void)
+{
+	int i;
+	unsigned int order = get_order(IRQ_STACK_SIZE);
+	struct page *page;
+
+	clear_csr_ecfg(ECFG0_IM);
+	clear_csr_estat(ESTATF_IP);
+
+	irqchip_init();
+
+	for (i = 0; i < NR_IRQS; i++)
+		irq_set_noprobe(i);
+
+	for_each_possible_cpu(i) {
+		page = alloc_pages_node(cpu_to_node(i), GFP_KERNEL, order);
+
+		per_cpu(irq_stack, i) = (unsigned long)page_address(page);
+		pr_debug("CPU%d IRQ stack at 0x%lx - 0x%lx\n", i,
+			per_cpu(irq_stack, i), per_cpu(irq_stack, i) + IRQ_STACK_SIZE);
+	}
+
+	set_csr_ecfg(ECFGF_IP0 | ECFGF_IP1 | ECFGF_IP2 | ECFGF_IPI | ECFGF_PMC);
+}