1 // SPDX-License-Identifier: GPL-2.0-only
3 * Multiplex several IPIs over a single HW IPI.
5 * Copyright (c) 2022 Ventana Micro Systems Inc.
8 #define pr_fmt(fmt) "riscv: " fmt
10 #include <linux/init.h>
11 #include <linux/irq.h>
12 #include <linux/irqchip/chained_irq.h>
13 #include <linux/irqdomain.h>
16 static int sbi_ipi_virq;
18 static void sbi_ipi_handle(struct irq_desc *desc)
20 struct irq_chip *chip = irq_desc_get_chip(desc);
22 chained_irq_enter(chip, desc);
24 csr_clear(CSR_IP, IE_SIE);
27 chained_irq_exit(chip, desc);
30 static int sbi_ipi_starting_cpu(unsigned int cpu)
32 enable_percpu_irq(sbi_ipi_virq, irq_get_trigger_type(sbi_ipi_virq));
36 void __init sbi_ipi_init(void)
39 struct irq_domain *domain;
41 if (riscv_ipi_have_virq_range())
44 domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(),
47 pr_err("unable to find INTC IRQ domain\n");
51 sbi_ipi_virq = irq_create_mapping(domain, RV_IRQ_SOFT);
53 pr_err("unable to create INTC IRQ mapping\n");
57 virq = ipi_mux_create(BITS_PER_BYTE, sbi_send_ipi);
59 pr_err("unable to create muxed IPIs\n");
60 irq_dispose_mapping(sbi_ipi_virq);
64 irq_set_chained_handler(sbi_ipi_virq, sbi_ipi_handle);
67 * Don't disable IPI when CPU goes offline because
68 * the masking/unmasking of virtual IPIs is done
71 cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
72 "irqchip/sbi-ipi:starting",
73 sbi_ipi_starting_cpu, NULL);
75 riscv_ipi_set_virq_range(virq, BITS_PER_BYTE, false);
76 pr_info("providing IPIs using SBI IPI extension\n");