diff options
Diffstat (limited to 'drivers/irqchip/irq-riscv-imsic-early.c')
| -rw-r--r-- | drivers/irqchip/irq-riscv-imsic-early.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-riscv-imsic-early.c b/drivers/irqchip/irq-riscv-imsic-early.c new file mode 100644 index 000000000000..886418ec06cb --- /dev/null +++ b/drivers/irqchip/irq-riscv-imsic-early.c @@ -0,0 +1,201 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 Western Digital Corporation or its affiliates. + * Copyright (C) 2022 Ventana Micro Systems Inc. + */ + +#define pr_fmt(fmt) "riscv-imsic: " fmt +#include <linux/cpu.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/irqchip.h> +#include <linux/irqchip/chained_irq.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/smp.h> + +#include "irq-riscv-imsic-state.h" + +static int imsic_parent_irq; + +#ifdef CONFIG_SMP +static void imsic_ipi_send(unsigned int cpu) +{ + struct imsic_local_config *local = per_cpu_ptr(imsic->global.local, cpu); + + writel_relaxed(IMSIC_IPI_ID, local->msi_va); +} + +static void imsic_ipi_starting_cpu(void) +{ + /* Enable IPIs for current CPU. */ + __imsic_id_set_enable(IMSIC_IPI_ID); +} + +static void imsic_ipi_dying_cpu(void) +{ + /* Disable IPIs for current CPU. */ + __imsic_id_clear_enable(IMSIC_IPI_ID); +} + +static int __init imsic_ipi_domain_init(void) +{ + int virq; + + /* Create IMSIC IPI multiplexing */ + virq = ipi_mux_create(IMSIC_NR_IPI, imsic_ipi_send); + if (virq <= 0) + return virq < 0 ? virq : -ENOMEM; + + /* Set vIRQ range */ + riscv_ipi_set_virq_range(virq, IMSIC_NR_IPI, true); + + /* Announce that IMSIC is providing IPIs */ + pr_info("%pfwP: providing IPIs using interrupt %d\n", imsic->fwnode, IMSIC_IPI_ID); + + return 0; +} +#else +static void imsic_ipi_starting_cpu(void) { } +static void imsic_ipi_dying_cpu(void) { } +static int __init imsic_ipi_domain_init(void) { return 0; } +#endif + +/* + * To handle an interrupt, we read the TOPEI CSR and write zero in one + * instruction. If TOPEI CSR is non-zero then we translate TOPEI.ID to + * Linux interrupt number and let Linux IRQ subsystem handle it. + */ +static void imsic_handle_irq(struct irq_desc *desc) +{ + struct irq_chip *chip = irq_desc_get_chip(desc); + int err, cpu = smp_processor_id(); + struct imsic_vector *vec; + unsigned long local_id; + + chained_irq_enter(chip, desc); + + while ((local_id = csr_swap(CSR_TOPEI, 0))) { + local_id >>= TOPEI_ID_SHIFT; + + if (local_id == IMSIC_IPI_ID) { + if (IS_ENABLED(CONFIG_SMP)) + ipi_mux_process(); + continue; + } + + if (unlikely(!imsic->base_domain)) + continue; + + vec = imsic_vector_from_local_id(cpu, local_id); + if (!vec) { + pr_warn_ratelimited("vector not found for local ID 0x%lx\n", local_id); + continue; + } + + err = generic_handle_domain_irq(imsic->base_domain, vec->hwirq); + if (unlikely(err)) + pr_warn_ratelimited("hwirq 0x%x mapping not found\n", vec->hwirq); + } + + chained_irq_exit(chip, desc); +} + +static int imsic_starting_cpu(unsigned int cpu) +{ + /* Mark per-CPU IMSIC state as online */ + imsic_state_online(); + + /* Enable per-CPU parent interrupt */ + enable_percpu_irq(imsic_parent_irq, irq_get_trigger_type(imsic_parent_irq)); + + /* Setup IPIs */ + imsic_ipi_starting_cpu(); + + /* + * Interrupts identities might have been enabled/disabled while + * this CPU was not running so sync-up local enable/disable state. + */ + imsic_local_sync_all(); + + /* Enable local interrupt delivery */ + imsic_local_delivery(true); + + return 0; +} + +static int imsic_dying_cpu(unsigned int cpu) +{ + /* Cleanup IPIs */ + imsic_ipi_dying_cpu(); + + /* Mark per-CPU IMSIC state as offline */ + imsic_state_offline(); + + return 0; +} + +static int __init imsic_early_probe(struct fwnode_handle *fwnode) +{ + struct irq_domain *domain; + int rc; + + /* Find parent domain and register chained handler */ + domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), DOMAIN_BUS_ANY); + if (!domain) { + pr_err("%pfwP: Failed to find INTC domain\n", fwnode); + return -ENOENT; + } + imsic_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT); + if (!imsic_parent_irq) { + pr_err("%pfwP: Failed to create INTC mapping\n", fwnode); + return -ENOENT; + } + + /* Initialize IPI domain */ + rc = imsic_ipi_domain_init(); + if (rc) { + pr_err("%pfwP: Failed to initialize IPI domain\n", fwnode); + return rc; + } + + /* Setup chained handler to the parent domain interrupt */ + irq_set_chained_handler(imsic_parent_irq, imsic_handle_irq); + + /* + * Setup cpuhp state (must be done after setting imsic_parent_irq) + * + * Don't disable per-CPU IMSIC file when CPU goes offline + * because this affects IPI and the masking/unmasking of + * virtual IPIs is done via generic IPI-Mux + */ + cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_IMSIC_STARTING, "irqchip/riscv/imsic:starting", + imsic_starting_cpu, imsic_dying_cpu); + + return 0; +} + +static int __init imsic_early_dt_init(struct device_node *node, struct device_node *parent) +{ + struct fwnode_handle *fwnode = &node->fwnode; + int rc; + + /* Setup IMSIC state */ + rc = imsic_setup_state(fwnode); + if (rc) { + pr_err("%pfwP: failed to setup state (error %d)\n", fwnode, rc); + return rc; + } + + /* Do early setup of IPIs */ + rc = imsic_early_probe(fwnode); + if (rc) + return rc; + + /* Ensure that OF platform device gets probed */ + of_node_clear_flag(node, OF_POPULATED); + return 0; +} + +IRQCHIP_DECLARE(riscv_imsic, "riscv,imsics", imsic_early_dt_init); |