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-rw-r--r--drivers/irqchip/irq-riscv-intc.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
new file mode 100644
index 000000000..4b6685097
--- /dev/null
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -0,0 +1,147 @@
+// 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:
+ generic_handle_domain_irq(intc_domain, cause);
+ 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;
+ unsigned long hartid;
+
+ rc = riscv_of_parent_hartid(node, &hartid);
+ if (rc < 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()) {
+ /*
+ * The INTC nodes of each CPU are suppliers for downstream
+ * interrupt controllers (such as PLIC, IMSIC and APLIC
+ * direct-mode) so we should mark an INTC node as initialized
+ * if we are not creating IRQ domain for it.
+ */
+ fwnode_dev_initialized(of_fwnode_handle(node), true);
+ 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);