1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Multiplex several IPIs over a single HW IPI. 4 * 5 * Copyright (c) 2022 Ventana Micro Systems Inc. 6 */ 7 8 #define pr_fmt(fmt) "riscv: " fmt 9 #include <linux/cpu.h> 10 #include <linux/init.h> 11 #include <linux/irq.h> 12 #include <linux/irqchip/chained_irq.h> 13 #include <linux/irqdomain.h> 14 #include <asm/sbi.h> 15 16 static int sbi_ipi_virq; 17 18 static void sbi_ipi_handle(struct irq_desc *desc) 19 { 20 struct irq_chip *chip = irq_desc_get_chip(desc); 21 22 chained_irq_enter(chip, desc); 23 24 csr_clear(CSR_IP, IE_SIE); 25 ipi_mux_process(); 26 27 chained_irq_exit(chip, desc); 28 } 29 30 static int sbi_ipi_starting_cpu(unsigned int cpu) 31 { 32 enable_percpu_irq(sbi_ipi_virq, irq_get_trigger_type(sbi_ipi_virq)); 33 return 0; 34 } 35 36 void __init sbi_ipi_init(void) 37 { 38 int virq; 39 struct irq_domain *domain; 40 41 if (riscv_ipi_have_virq_range()) 42 return; 43 44 domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), 45 DOMAIN_BUS_ANY); 46 if (!domain) { 47 pr_err("unable to find INTC IRQ domain\n"); 48 return; 49 } 50 51 sbi_ipi_virq = irq_create_mapping(domain, RV_IRQ_SOFT); 52 if (!sbi_ipi_virq) { 53 pr_err("unable to create INTC IRQ mapping\n"); 54 return; 55 } 56 57 virq = ipi_mux_create(BITS_PER_BYTE, sbi_send_ipi); 58 if (virq <= 0) { 59 pr_err("unable to create muxed IPIs\n"); 60 irq_dispose_mapping(sbi_ipi_virq); 61 return; 62 } 63 64 irq_set_chained_handler(sbi_ipi_virq, sbi_ipi_handle); 65 66 /* 67 * Don't disable IPI when CPU goes offline because 68 * the masking/unmasking of virtual IPIs is done 69 * via generic IPI-Mux 70 */ 71 cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, 72 "irqchip/sbi-ipi:starting", 73 sbi_ipi_starting_cpu, NULL); 74 75 riscv_ipi_set_virq_range(virq, BITS_PER_BYTE, false); 76 pr_info("providing IPIs using SBI IPI extension\n"); 77 } 78