irq-riscv-intc.c
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 Regents of the University of California
* Copyright (C) 2017-2018 SiFive
* Copyright (C) 2020 Western Digital Corporation or its affiliates.
*/
#define pr_fmt(fmt) "riscv-intc: " fmt
#include <linux/atomic.h>
#include <linux/bits.h>
#include <linux/cpu.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/smp.h>
static struct irq_domain *intc_domain;
static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
{
unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
if (unlikely(cause >= BITS_PER_LONG))
panic("unexpected interrupt cause");
switch (cause) {
#ifdef CONFIG_SMP
case RV_IRQ_SOFT:
/*
* We only use software interrupts to pass IPIs, so if a
* non-SMP system gets one, then we don't know what to do.
*/
handle_IPI(regs);
break;
#endif
default:
handle_domain_irq(intc_domain, cause, regs);
break;
}
}
/*
* On RISC-V systems local interrupts are masked or unmasked by writing
* the SIE (Supervisor Interrupt Enable) CSR. As CSRs can only be written
* on the local hart, these functions can only be called on the hart that
* corresponds to the IRQ chip.
*/
static void riscv_intc_irq_mask(struct irq_data *d)
{
csr_clear(CSR_IE, BIT(d->hwirq));
}
static void riscv_intc_irq_unmask(struct irq_data *d)
{
csr_set(CSR_IE, BIT(d->hwirq));
}
static int riscv_intc_cpu_starting(unsigned int cpu)
{
csr_set(CSR_IE, BIT(RV_IRQ_SOFT));
return 0;
}
static int riscv_intc_cpu_dying(unsigned int cpu)
{
csr_clear(CSR_IE, BIT(RV_IRQ_SOFT));
return 0;
}
static struct irq_chip riscv_intc_chip = {
.name = "RISC-V INTC",
.irq_mask = riscv_intc_irq_mask,
.irq_unmask = riscv_intc_irq_unmask,
};
static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
irq_set_percpu_devid(irq);
irq_domain_set_info(d, irq, hwirq, &riscv_intc_chip, d->host_data,
handle_percpu_devid_irq, NULL, NULL);
return 0;
}
static const struct irq_domain_ops riscv_intc_domain_ops = {
.map = riscv_intc_domain_map,
.xlate = irq_domain_xlate_onecell,
};
static int __init riscv_intc_init(struct device_node *node,
struct device_node *parent)
{
int rc, hartid;
hartid = riscv_of_parent_hartid(node);
if (hartid < 0) {
pr_warn("unable to find hart id for %pOF\n", node);
return 0;
}
/*
* The DT will have one INTC DT node under each CPU (or HART)
* DT node so riscv_intc_init() function will be called once
* for each INTC DT node. We only need to do INTC initialization
* for the INTC DT node belonging to boot CPU (or boot HART).
*/
if (riscv_hartid_to_cpuid(hartid) != smp_processor_id())
return 0;
intc_domain = irq_domain_add_linear(node, BITS_PER_LONG,
&riscv_intc_domain_ops, NULL);
if (!intc_domain) {
pr_err("unable to add IRQ domain\n");
return -ENXIO;
}
rc = set_handle_irq(&riscv_intc_irq);
if (rc) {
pr_err("failed to set irq handler\n");
return rc;
}
cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_STARTING,
"irqchip/riscv/intc:starting",
riscv_intc_cpu_starting,
riscv_intc_cpu_dying);
pr_info("%d local interrupts mapped\n", BITS_PER_LONG);
return 0;
}
IRQCHIP_DECLARE(riscv, "riscv,cpu-intc", riscv_intc_init);