// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2017 SiFive * Copyright (C) 2018 Christoph Hellwig */ #define pr_fmt(fmt) "riscv-plic: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * This driver implements a version of the RISC-V PLIC with the actual layout * specified in chapter 8 of the SiFive U5 Coreplex Series Manual: * * https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf * * The largest number supported by devices marked as 'sifive,plic-1.0.0', is * 1024, of which device 0 is defined as non-existent by the RISC-V Privileged * Spec. */ #define MAX_DEVICES 1024 #define MAX_CONTEXTS 15872 /* * Each interrupt source has a priority register associated with it. * We always hardwire it to one in Linux. */ #define PRIORITY_BASE 0 #define PRIORITY_PER_ID 4 /* * Each hart context has a vector of interrupt enable bits associated with it. * There's one bit for each interrupt source. */ #define CONTEXT_ENABLE_BASE 0x2000 #define CONTEXT_ENABLE_SIZE 0x80 /* * Each hart context has a set of control registers associated with it. Right * now there's only two: a source priority threshold over which the hart will * take an interrupt, and a register to claim interrupts. */ #define CONTEXT_BASE 0x200000 #define CONTEXT_SIZE 0x1000 #define CONTEXT_THRESHOLD 0x00 #define CONTEXT_CLAIM 0x04 #define PLIC_DISABLE_THRESHOLD 0x7 #define PLIC_ENABLE_THRESHOLD 0 #define PLIC_QUIRK_EDGE_INTERRUPT 0 struct plic_priv { struct fwnode_handle *fwnode; struct cpumask lmask; struct irq_domain *irqdomain; void __iomem *regs; unsigned long plic_quirks; unsigned int nr_irqs; unsigned long *prio_save; u32 gsi_base; int acpi_plic_id; }; struct plic_handler { bool present; void __iomem *hart_base; /* * Protect mask operations on the registers given that we can't * assume atomic memory operations work on them. */ raw_spinlock_t enable_lock; void __iomem *enable_base; u32 *enable_save; struct plic_priv *priv; }; static int plic_parent_irq __ro_after_init; static bool plic_global_setup_done __ro_after_init; static DEFINE_PER_CPU(struct plic_handler, plic_handlers); static int plic_irq_set_type(struct irq_data *d, unsigned int type); static void __plic_toggle(void __iomem *enable_base, int hwirq, int enable) { u32 __iomem *reg = enable_base + (hwirq / 32) * sizeof(u32); u32 hwirq_mask = 1 << (hwirq % 32); if (enable) writel(readl(reg) | hwirq_mask, reg); else writel(readl(reg) & ~hwirq_mask, reg); } static void plic_toggle(struct plic_handler *handler, int hwirq, int enable) { unsigned long flags; raw_spin_lock_irqsave(&handler->enable_lock, flags); __plic_toggle(handler->enable_base, hwirq, enable); raw_spin_unlock_irqrestore(&handler->enable_lock, flags); } static inline void plic_irq_toggle(const struct cpumask *mask, struct irq_data *d, int enable) { int cpu; for_each_cpu(cpu, mask) { struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu); plic_toggle(handler, d->hwirq, enable); } } static void plic_irq_unmask(struct irq_data *d) { struct plic_priv *priv = irq_data_get_irq_chip_data(d); writel(1, priv->regs + PRIORITY_BASE + d->hwirq * PRIORITY_PER_ID); } static void plic_irq_mask(struct irq_data *d) { struct plic_priv *priv = irq_data_get_irq_chip_data(d); writel(0, priv->regs + PRIORITY_BASE + d->hwirq * PRIORITY_PER_ID); } static void plic_irq_enable(struct irq_data *d) { plic_irq_toggle(irq_data_get_effective_affinity_mask(d), d, 1); plic_irq_unmask(d); } static void plic_irq_disable(struct irq_data *d) { plic_irq_toggle(irq_data_get_effective_affinity_mask(d), d, 0); } static void plic_irq_eoi(struct irq_data *d) { struct plic_handler *handler = this_cpu_ptr(&plic_handlers); if (unlikely(irqd_irq_disabled(d))) { plic_toggle(handler, d->hwirq, 1); writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM); plic_toggle(handler, d->hwirq, 0); } else { writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM); } } #ifdef CONFIG_SMP static int plic_set_affinity(struct irq_data *d, const struct cpumask *mask_val, bool force) { unsigned int cpu; struct plic_priv *priv = irq_data_get_irq_chip_data(d); if (force) cpu = cpumask_first_and(&priv->lmask, mask_val); else cpu = cpumask_first_and_and(&priv->lmask, mask_val, cpu_online_mask); if (cpu >= nr_cpu_ids) return -EINVAL; /* Invalidate the original routing entry */ plic_irq_toggle(irq_data_get_effective_affinity_mask(d), d, 0); irq_data_update_effective_affinity(d, cpumask_of(cpu)); /* Setting the new routing entry if irq is enabled */ if (!irqd_irq_disabled(d)) plic_irq_toggle(irq_data_get_effective_affinity_mask(d), d, 1); return IRQ_SET_MASK_OK_DONE; } #endif static struct irq_chip plic_edge_chip = { .name = "SiFive PLIC", .irq_enable = plic_irq_enable, .irq_disable = plic_irq_disable, .irq_ack = plic_irq_eoi, .irq_mask = plic_irq_mask, .irq_unmask = plic_irq_unmask, #ifdef CONFIG_SMP .irq_set_affinity = plic_set_affinity, #endif .irq_set_type = plic_irq_set_type, .flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_AFFINITY_PRE_STARTUP, }; static struct irq_chip plic_chip = { .name = "SiFive PLIC", .irq_enable = plic_irq_enable, .irq_disable = plic_irq_disable, .irq_mask = plic_irq_mask, .irq_unmask = plic_irq_unmask, .irq_eoi = plic_irq_eoi, #ifdef CONFIG_SMP .irq_set_affinity = plic_set_affinity, #endif .irq_set_type = plic_irq_set_type, .flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_AFFINITY_PRE_STARTUP, }; static int plic_irq_set_type(struct irq_data *d, unsigned int type) { struct plic_priv *priv = irq_data_get_irq_chip_data(d); if (!test_bit(PLIC_QUIRK_EDGE_INTERRUPT, &priv->plic_quirks)) return IRQ_SET_MASK_OK_NOCOPY; switch (type) { case IRQ_TYPE_EDGE_RISING: irq_set_chip_handler_name_locked(d, &plic_edge_chip, handle_edge_irq, NULL); break; case IRQ_TYPE_LEVEL_HIGH: irq_set_chip_handler_name_locked(d, &plic_chip, handle_fasteoi_irq, NULL); break; default: return -EINVAL; } return IRQ_SET_MASK_OK; } static int plic_irq_suspend(void) { unsigned int i, cpu; unsigned long flags; u32 __iomem *reg; struct plic_priv *priv; priv = per_cpu_ptr(&plic_handlers, smp_processor_id())->priv; /* irq ID 0 is reserved */ for (i = 1; i < priv->nr_irqs; i++) { __assign_bit(i, priv->prio_save, readl(priv->regs + PRIORITY_BASE + i * PRIORITY_PER_ID)); } for_each_present_cpu(cpu) { struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu); if (!handler->present) continue; raw_spin_lock_irqsave(&handler->enable_lock, flags); for (i = 0; i < DIV_ROUND_UP(priv->nr_irqs, 32); i++) { reg = handler->enable_base + i * sizeof(u32); handler->enable_save[i] = readl(reg); } raw_spin_unlock_irqrestore(&handler->enable_lock, flags); } return 0; } static void plic_irq_resume(void) { unsigned int i, index, cpu; unsigned long flags; u32 __iomem *reg; struct plic_priv *priv; priv = per_cpu_ptr(&plic_handlers, smp_processor_id())->priv; /* irq ID 0 is reserved */ for (i = 1; i < priv->nr_irqs; i++) { index = BIT_WORD(i); writel((priv->prio_save[index] & BIT_MASK(i)) ? 1 : 0, priv->regs + PRIORITY_BASE + i * PRIORITY_PER_ID); } for_each_present_cpu(cpu) { struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu); if (!handler->present) continue; raw_spin_lock_irqsave(&handler->enable_lock, flags); for (i = 0; i < DIV_ROUND_UP(priv->nr_irqs, 32); i++) { reg = handler->enable_base + i * sizeof(u32); writel(handler->enable_save[i], reg); } raw_spin_unlock_irqrestore(&handler->enable_lock, flags); } } static struct syscore_ops plic_irq_syscore_ops = { .suspend = plic_irq_suspend, .resume = plic_irq_resume, }; static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq) { struct plic_priv *priv = d->host_data; irq_domain_set_info(d, irq, hwirq, &plic_chip, d->host_data, handle_fasteoi_irq, NULL, NULL); irq_set_noprobe(irq); irq_set_affinity(irq, &priv->lmask); return 0; } static int plic_irq_domain_translate(struct irq_domain *d, struct irq_fwspec *fwspec, unsigned long *hwirq, unsigned int *type) { struct plic_priv *priv = d->host_data; /* For DT, gsi_base is always zero. */ if (fwspec->param[0] >= priv->gsi_base) fwspec->param[0] = fwspec->param[0] - priv->gsi_base; if (test_bit(PLIC_QUIRK_EDGE_INTERRUPT, &priv->plic_quirks)) return irq_domain_translate_twocell(d, fwspec, hwirq, type); return irq_domain_translate_onecell(d, fwspec, hwirq, type); } static int plic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq, unsigned int nr_irqs, void *arg) { int i, ret; irq_hw_number_t hwirq; unsigned int type; struct irq_fwspec *fwspec = arg; ret = plic_irq_domain_translate(domain, fwspec, &hwirq, &type); if (ret) return ret; for (i = 0; i < nr_irqs; i++) { ret = plic_irqdomain_map(domain, virq + i, hwirq + i); if (ret) return ret; } return 0; } static const struct irq_domain_ops plic_irqdomain_ops = { .translate = plic_irq_domain_translate, .alloc = plic_irq_domain_alloc, .free = irq_domain_free_irqs_top, }; /* * Handling an interrupt is a two-step process: first you claim the interrupt * by reading the claim register, then you complete the interrupt by writing * that source ID back to the same claim register. This automatically enables * and disables the interrupt, so there's nothing else to do. */ static void plic_handle_irq(struct irq_desc *desc) { struct plic_handler *handler = this_cpu_ptr(&plic_handlers); struct irq_chip *chip = irq_desc_get_chip(desc); void __iomem *claim = handler->hart_base + CONTEXT_CLAIM; irq_hw_number_t hwirq; WARN_ON_ONCE(!handler->present); chained_irq_enter(chip, desc); while ((hwirq = readl(claim))) { int err = generic_handle_domain_irq(handler->priv->irqdomain, hwirq); if (unlikely(err)) { pr_warn_ratelimited("%pfwP: can't find mapping for hwirq %lu\n", handler->priv->fwnode, hwirq); } } chained_irq_exit(chip, desc); } static void plic_set_threshold(struct plic_handler *handler, u32 threshold) { /* priority must be > threshold to trigger an interrupt */ writel(threshold, handler->hart_base + CONTEXT_THRESHOLD); } static int plic_dying_cpu(unsigned int cpu) { if (plic_parent_irq) disable_percpu_irq(plic_parent_irq); return 0; } static int plic_starting_cpu(unsigned int cpu) { struct plic_handler *handler = this_cpu_ptr(&plic_handlers); if (plic_parent_irq) enable_percpu_irq(plic_parent_irq, irq_get_trigger_type(plic_parent_irq)); else pr_warn("%pfwP: cpu%d: parent irq not available\n", handler->priv->fwnode, cpu); plic_set_threshold(handler, PLIC_ENABLE_THRESHOLD); return 0; } static const struct of_device_id plic_match[] = { { .compatible = "sifive,plic-1.0.0" }, { .compatible = "riscv,plic0" }, { .compatible = "andestech,nceplic100", .data = (const void *)BIT(PLIC_QUIRK_EDGE_INTERRUPT) }, { .compatible = "thead,c900-plic", .data = (const void *)BIT(PLIC_QUIRK_EDGE_INTERRUPT) }, {} }; #ifdef CONFIG_ACPI static const struct acpi_device_id plic_acpi_match[] = { { "RSCV0001", 0 }, {} }; MODULE_DEVICE_TABLE(acpi, plic_acpi_match); #endif static int plic_parse_nr_irqs_and_contexts(struct fwnode_handle *fwnode, u32 *nr_irqs, u32 *nr_contexts, u32 *gsi_base, u32 *id) { int rc; if (!is_of_node(fwnode)) { rc = riscv_acpi_get_gsi_info(fwnode, gsi_base, id, nr_irqs, NULL); if (rc) { pr_err("%pfwP: failed to find GSI mapping\n", fwnode); return rc; } *nr_contexts = acpi_rintc_get_plic_nr_contexts(*id); if (WARN_ON(!*nr_contexts)) { pr_err("%pfwP: no PLIC context available\n", fwnode); return -EINVAL; } return 0; } rc = of_property_read_u32(to_of_node(fwnode), "riscv,ndev", nr_irqs); if (rc) { pr_err("%pfwP: riscv,ndev property not available\n", fwnode); return rc; } *nr_contexts = of_irq_count(to_of_node(fwnode)); if (WARN_ON(!(*nr_contexts))) { pr_err("%pfwP: no PLIC context available\n", fwnode); return -EINVAL; } *gsi_base = 0; *id = 0; return 0; } static int plic_parse_context_parent(struct fwnode_handle *fwnode, u32 context, u32 *parent_hwirq, int *parent_cpu, u32 id) { struct of_phandle_args parent; unsigned long hartid; int rc; if (!is_of_node(fwnode)) { hartid = acpi_rintc_ext_parent_to_hartid(id, context); if (hartid == INVALID_HARTID) return -EINVAL; *parent_cpu = riscv_hartid_to_cpuid(hartid); *parent_hwirq = RV_IRQ_EXT; return 0; } rc = of_irq_parse_one(to_of_node(fwnode), context, &parent); if (rc) return rc; rc = riscv_of_parent_hartid(parent.np, &hartid); if (rc) return rc; *parent_hwirq = parent.args[0]; *parent_cpu = riscv_hartid_to_cpuid(hartid); return 0; } static int plic_probe(struct fwnode_handle *fwnode) { int error = 0, nr_contexts, nr_handlers = 0, cpu, i; unsigned long plic_quirks = 0; struct plic_handler *handler; u32 nr_irqs, parent_hwirq; struct plic_priv *priv; irq_hw_number_t hwirq; void __iomem *regs; int id, context_id; u32 gsi_base; if (is_of_node(fwnode)) { const struct of_device_id *id; id = of_match_node(plic_match, to_of_node(fwnode)); if (id) plic_quirks = (unsigned long)id->data; regs = of_iomap(to_of_node(fwnode), 0); if (!regs) return -ENOMEM; } else { regs = devm_platform_ioremap_resource(to_platform_device(fwnode->dev), 0); if (IS_ERR(regs)) return PTR_ERR(regs); } error = plic_parse_nr_irqs_and_contexts(fwnode, &nr_irqs, &nr_contexts, &gsi_base, &id); if (error) goto fail_free_regs; priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) { error = -ENOMEM; goto fail_free_regs; } priv->fwnode = fwnode; priv->plic_quirks = plic_quirks; priv->nr_irqs = nr_irqs; priv->regs = regs; priv->gsi_base = gsi_base; priv->acpi_plic_id = id; priv->prio_save = bitmap_zalloc(nr_irqs, GFP_KERNEL); if (!priv->prio_save) { error = -ENOMEM; goto fail_free_priv; } for (i = 0; i < nr_contexts; i++) { error = plic_parse_context_parent(fwnode, i, &parent_hwirq, &cpu, priv->acpi_plic_id); if (error) { pr_warn("%pfwP: hwirq for context%d not found\n", fwnode, i); continue; } if (is_of_node(fwnode)) { context_id = i; } else { context_id = acpi_rintc_get_plic_context(priv->acpi_plic_id, i); if (context_id == INVALID_CONTEXT) { pr_warn("%pfwP: invalid context id for context%d\n", fwnode, i); continue; } } /* * Skip contexts other than external interrupts for our * privilege level. */ if (parent_hwirq != RV_IRQ_EXT) { /* Disable S-mode enable bits if running in M-mode. */ if (IS_ENABLED(CONFIG_RISCV_M_MODE)) { void __iomem *enable_base = priv->regs + CONTEXT_ENABLE_BASE + i * CONTEXT_ENABLE_SIZE; for (hwirq = 1; hwirq <= nr_irqs; hwirq++) __plic_toggle(enable_base, hwirq, 0); } continue; } if (cpu < 0) { pr_warn("%pfwP: Invalid cpuid for context %d\n", fwnode, i); continue; } /* * When running in M-mode we need to ignore the S-mode handler. * Here we assume it always comes later, but that might be a * little fragile. */ handler = per_cpu_ptr(&plic_handlers, cpu); if (handler->present) { pr_warn("%pfwP: handler already present for context %d.\n", fwnode, i); plic_set_threshold(handler, PLIC_DISABLE_THRESHOLD); goto done; } cpumask_set_cpu(cpu, &priv->lmask); handler->present = true; handler->hart_base = priv->regs + CONTEXT_BASE + context_id * CONTEXT_SIZE; raw_spin_lock_init(&handler->enable_lock); handler->enable_base = priv->regs + CONTEXT_ENABLE_BASE + context_id * CONTEXT_ENABLE_SIZE; handler->priv = priv; handler->enable_save = kcalloc(DIV_ROUND_UP(nr_irqs, 32), sizeof(*handler->enable_save), GFP_KERNEL); if (!handler->enable_save) { error = -ENOMEM; goto fail_cleanup_contexts; } done: for (hwirq = 1; hwirq <= nr_irqs; hwirq++) { plic_toggle(handler, hwirq, 0); writel(1, priv->regs + PRIORITY_BASE + hwirq * PRIORITY_PER_ID); } nr_handlers++; } priv->irqdomain = irq_domain_create_linear(fwnode, nr_irqs + 1, &plic_irqdomain_ops, priv); if (WARN_ON(!priv->irqdomain)) { error = -ENOMEM; goto fail_cleanup_contexts; } /* * We can have multiple PLIC instances so setup global state * and register syscore operations only once after context * handlers of all online CPUs are initialized. */ if (!plic_global_setup_done) { struct irq_domain *domain; bool global_setup = true; for_each_online_cpu(cpu) { handler = per_cpu_ptr(&plic_handlers, cpu); if (!handler->present) { global_setup = false; break; } } if (global_setup) { /* Find parent domain and register chained handler */ domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), DOMAIN_BUS_ANY); if (domain) plic_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT); if (plic_parent_irq) irq_set_chained_handler(plic_parent_irq, plic_handle_irq); cpuhp_setup_state(CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING, "irqchip/sifive/plic:starting", plic_starting_cpu, plic_dying_cpu); register_syscore_ops(&plic_irq_syscore_ops); plic_global_setup_done = true; } } #ifdef CONFIG_ACPI if (!acpi_disabled) acpi_dev_clear_dependencies(ACPI_COMPANION(fwnode->dev)); #endif pr_info("%pfwP: mapped %d interrupts with %d handlers for %d contexts.\n", fwnode, nr_irqs, nr_handlers, nr_contexts); return 0; fail_cleanup_contexts: for (i = 0; i < nr_contexts; i++) { if (plic_parse_context_parent(fwnode, i, &parent_hwirq, &cpu, priv->acpi_plic_id)) continue; if (parent_hwirq != RV_IRQ_EXT || cpu < 0) continue; handler = per_cpu_ptr(&plic_handlers, cpu); handler->present = false; handler->hart_base = NULL; handler->enable_base = NULL; kfree(handler->enable_save); handler->enable_save = NULL; handler->priv = NULL; } bitmap_free(priv->prio_save); fail_free_priv: kfree(priv); fail_free_regs: iounmap(regs); return error; } static int plic_platform_probe(struct platform_device *pdev) { return plic_probe(pdev->dev.fwnode); } static struct platform_driver plic_driver = { .driver = { .name = "riscv-plic", .of_match_table = plic_match, .suppress_bind_attrs = true, .acpi_match_table = ACPI_PTR(plic_acpi_match), }, .probe = plic_platform_probe, }; builtin_platform_driver(plic_driver); static int __init plic_early_probe(struct device_node *node, struct device_node *parent) { return plic_probe(&node->fwnode); } IRQCHIP_DECLARE(riscv, "allwinner,sun20i-d1-plic", plic_early_probe);