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-rw-r--r--arch/riscv/kernel/irq.c55
1 files changed, 46 insertions, 9 deletions
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 7bcdaed15703..0cfac48a1272 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -1,21 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 Regents of the University of California
* Copyright (C) 2017 SiFive
- *
- * 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, version 2.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * Copyright (C) 2018 Christoph Hellwig
*/
#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
+/*
+ * Possible interrupt causes:
+ */
+#define INTERRUPT_CAUSE_SOFTWARE 1
+#define INTERRUPT_CAUSE_TIMER 5
+#define INTERRUPT_CAUSE_EXTERNAL 9
+
+/*
+ * The high order bit of the trap cause register is always set for
+ * interrupts, which allows us to differentiate them from exceptions
+ * quickly. The INTERRUPT_CAUSE_* macros don't contain that bit, so we
+ * need to mask it off.
+ */
+#define INTERRUPT_CAUSE_FLAG (1UL << (__riscv_xlen - 1))
+
+asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause)
+{
+ struct pt_regs *old_regs = set_irq_regs(regs);
+
+ irq_enter();
+ switch (cause & ~INTERRUPT_CAUSE_FLAG) {
+ case INTERRUPT_CAUSE_TIMER:
+ riscv_timer_interrupt();
+ break;
+#ifdef CONFIG_SMP
+ case INTERRUPT_CAUSE_SOFTWARE:
+ /*
+ * We only use software interrupts to pass IPIs, so if a non-SMP
+ * system gets one, then we don't know what to do.
+ */
+ riscv_software_interrupt();
+ break;
+#endif
+ case INTERRUPT_CAUSE_EXTERNAL:
+ handle_arch_irq(regs);
+ break;
+ default:
+ panic("unexpected interrupt cause");
+ }
+ irq_exit();
+
+ set_irq_regs(old_regs);
+}
+
void __init init_IRQ(void)
{
irqchip_init();