1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2012 Regents of the University of California
4 * Copyright (C) 2017-2018 SiFive
5 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
8 #define pr_fmt(fmt) "riscv-intc: " fmt
9 #include <linux/atomic.h>
10 #include <linux/bits.h>
11 #include <linux/cpu.h>
12 #include <linux/irq.h>
13 #include <linux/irqchip.h>
14 #include <linux/irqdomain.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
18 #include <linux/smp.h>
20 static struct irq_domain *intc_domain;
22 static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
24 unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
26 if (unlikely(cause >= BITS_PER_LONG))
27 panic("unexpected interrupt cause");
33 * We only use software interrupts to pass IPIs, so if a
34 * non-SMP system gets one, then we don't know what to do.
40 handle_domain_irq(intc_domain, cause, regs);
46 * On RISC-V systems local interrupts are masked or unmasked by writing
47 * the SIE (Supervisor Interrupt Enable) CSR. As CSRs can only be written
48 * on the local hart, these functions can only be called on the hart that
49 * corresponds to the IRQ chip.
52 static void riscv_intc_irq_mask(struct irq_data *d)
54 csr_clear(CSR_IE, BIT(d->hwirq));
57 static void riscv_intc_irq_unmask(struct irq_data *d)
59 csr_set(CSR_IE, BIT(d->hwirq));
62 static int riscv_intc_cpu_starting(unsigned int cpu)
64 csr_set(CSR_IE, BIT(RV_IRQ_SOFT));
68 static int riscv_intc_cpu_dying(unsigned int cpu)
70 csr_clear(CSR_IE, BIT(RV_IRQ_SOFT));
74 static struct irq_chip riscv_intc_chip = {
75 .name = "RISC-V INTC",
76 .irq_mask = riscv_intc_irq_mask,
77 .irq_unmask = riscv_intc_irq_unmask,
80 static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
81 irq_hw_number_t hwirq)
83 irq_set_percpu_devid(irq);
84 irq_domain_set_info(d, irq, hwirq, &riscv_intc_chip, d->host_data,
85 handle_percpu_devid_irq, NULL, NULL);
90 static const struct irq_domain_ops riscv_intc_domain_ops = {
91 .map = riscv_intc_domain_map,
92 .xlate = irq_domain_xlate_onecell,
95 static int __init riscv_intc_init(struct device_node *node,
96 struct device_node *parent)
100 hartid = riscv_of_parent_hartid(node);
102 pr_warn("unable to fine hart id for %pOF\n", node);
107 * The DT will have one INTC DT node under each CPU (or HART)
108 * DT node so riscv_intc_init() function will be called once
109 * for each INTC DT node. We only need to do INTC initialization
110 * for the INTC DT node belonging to boot CPU (or boot HART).
112 if (riscv_hartid_to_cpuid(hartid) != smp_processor_id())
115 intc_domain = irq_domain_add_linear(node, BITS_PER_LONG,
116 &riscv_intc_domain_ops, NULL);
118 pr_err("unable to add IRQ domain\n");
122 rc = set_handle_irq(&riscv_intc_irq);
124 pr_err("failed to set irq handler\n");
128 cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_STARTING,
129 "irqchip/riscv/intc:starting",
130 riscv_intc_cpu_starting,
131 riscv_intc_cpu_dying);
133 pr_info("%d local interrupts mapped\n", BITS_PER_LONG);
138 IRQCHIP_DECLARE(riscv, "riscv,cpu-intc", riscv_intc_init);