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![Guo Ren](/assets/img/avatar_default.png)
When using "devm_request_threaded_irq(,,,,IRQF_ONESHOT,,)" in a driver, only the first interrupt is handled, and following interrupts are never delivered (initially reported in [1]). That's because the RISC-V PLIC cannot EOI masked interrupts, as explained in the description of Interrupt Completion in the PLIC spec [2]: <quote> The PLIC signals it has completed executing an interrupt handler by writing the interrupt ID it received from the claim to the claim/complete register. The PLIC does not check whether the completion ID is the same as the last claim ID for that target. If the completion ID does not match an interrupt source that *is currently enabled* for the target, the completion is silently ignored. </quote> Re-enable the interrupt before completion if it has been masked during the handling, and remask it afterwards. [1] http://lists.infradead.org/pipermail/linux-riscv/2021-July/007441.html [2]8bc15a35d0/riscv-plic.adoc
Fixes:bb0fed1c60
("irqchip/sifive-plic: Switch to fasteoi flow") Reported-by: Vincent Pelletier <plr.vincent@gmail.com> Tested-by: Nikita Shubin <nikita.shubin@maquefel.me> Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Atish Patra <atish.patra@wdc.com> Reviewed-by: Anup Patel <anup@brainfault.org> [maz: amended commit message] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211105094748.3894453-1-guoren@kernel.org
400 lines
10 KiB
C
400 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2017 SiFive
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* Copyright (C) 2018 Christoph Hellwig
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*/
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#define pr_fmt(fmt) "plic: " fmt
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#include <linux/cpu.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/irq.h>
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#include <linux/irqchip.h>
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#include <linux/irqchip/chained_irq.h>
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#include <linux/irqdomain.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include <asm/smp.h>
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/*
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* This driver implements a version of the RISC-V PLIC with the actual layout
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* specified in chapter 8 of the SiFive U5 Coreplex Series Manual:
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*
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* https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf
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*
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* The largest number supported by devices marked as 'sifive,plic-1.0.0', is
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* 1024, of which device 0 is defined as non-existent by the RISC-V Privileged
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* Spec.
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*/
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#define MAX_DEVICES 1024
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#define MAX_CONTEXTS 15872
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/*
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* Each interrupt source has a priority register associated with it.
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* We always hardwire it to one in Linux.
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*/
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#define PRIORITY_BASE 0
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#define PRIORITY_PER_ID 4
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/*
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* Each hart context has a vector of interrupt enable bits associated with it.
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* There's one bit for each interrupt source.
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*/
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#define ENABLE_BASE 0x2000
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#define ENABLE_PER_HART 0x80
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/*
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* Each hart context has a set of control registers associated with it. Right
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* now there's only two: a source priority threshold over which the hart will
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* take an interrupt, and a register to claim interrupts.
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*/
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#define CONTEXT_BASE 0x200000
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#define CONTEXT_PER_HART 0x1000
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#define CONTEXT_THRESHOLD 0x00
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#define CONTEXT_CLAIM 0x04
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#define PLIC_DISABLE_THRESHOLD 0x7
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#define PLIC_ENABLE_THRESHOLD 0
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struct plic_priv {
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struct cpumask lmask;
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struct irq_domain *irqdomain;
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void __iomem *regs;
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};
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struct plic_handler {
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bool present;
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void __iomem *hart_base;
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/*
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* Protect mask operations on the registers given that we can't
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* assume atomic memory operations work on them.
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*/
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raw_spinlock_t enable_lock;
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void __iomem *enable_base;
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struct plic_priv *priv;
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};
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static int plic_parent_irq __ro_after_init;
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static bool plic_cpuhp_setup_done __ro_after_init;
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static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
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static inline void plic_toggle(struct plic_handler *handler,
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int hwirq, int enable)
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{
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u32 __iomem *reg = handler->enable_base + (hwirq / 32) * sizeof(u32);
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u32 hwirq_mask = 1 << (hwirq % 32);
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raw_spin_lock(&handler->enable_lock);
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if (enable)
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writel(readl(reg) | hwirq_mask, reg);
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else
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writel(readl(reg) & ~hwirq_mask, reg);
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raw_spin_unlock(&handler->enable_lock);
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}
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static inline void plic_irq_toggle(const struct cpumask *mask,
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struct irq_data *d, int enable)
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{
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int cpu;
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struct plic_priv *priv = irq_data_get_irq_chip_data(d);
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writel(enable, priv->regs + PRIORITY_BASE + d->hwirq * PRIORITY_PER_ID);
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for_each_cpu(cpu, mask) {
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struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
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if (handler->present &&
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cpumask_test_cpu(cpu, &handler->priv->lmask))
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plic_toggle(handler, d->hwirq, enable);
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}
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}
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static void plic_irq_unmask(struct irq_data *d)
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{
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struct cpumask amask;
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unsigned int cpu;
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struct plic_priv *priv = irq_data_get_irq_chip_data(d);
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cpumask_and(&amask, &priv->lmask, cpu_online_mask);
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cpu = cpumask_any_and(irq_data_get_affinity_mask(d),
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&amask);
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if (WARN_ON_ONCE(cpu >= nr_cpu_ids))
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return;
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plic_irq_toggle(cpumask_of(cpu), d, 1);
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}
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static void plic_irq_mask(struct irq_data *d)
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{
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struct plic_priv *priv = irq_data_get_irq_chip_data(d);
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plic_irq_toggle(&priv->lmask, d, 0);
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}
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#ifdef CONFIG_SMP
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static int plic_set_affinity(struct irq_data *d,
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const struct cpumask *mask_val, bool force)
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{
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unsigned int cpu;
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struct cpumask amask;
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struct plic_priv *priv = irq_data_get_irq_chip_data(d);
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cpumask_and(&amask, &priv->lmask, mask_val);
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if (force)
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cpu = cpumask_first(&amask);
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else
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cpu = cpumask_any_and(&amask, cpu_online_mask);
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if (cpu >= nr_cpu_ids)
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return -EINVAL;
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plic_irq_toggle(&priv->lmask, d, 0);
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plic_irq_toggle(cpumask_of(cpu), d, !irqd_irq_masked(d));
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irq_data_update_effective_affinity(d, cpumask_of(cpu));
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return IRQ_SET_MASK_OK_DONE;
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}
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#endif
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static void plic_irq_eoi(struct irq_data *d)
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{
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struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
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if (irqd_irq_masked(d)) {
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plic_irq_unmask(d);
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writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
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plic_irq_mask(d);
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} else {
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writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
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}
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}
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static struct irq_chip plic_chip = {
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.name = "SiFive PLIC",
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.irq_mask = plic_irq_mask,
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.irq_unmask = plic_irq_unmask,
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.irq_eoi = plic_irq_eoi,
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#ifdef CONFIG_SMP
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.irq_set_affinity = plic_set_affinity,
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#endif
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};
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static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
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irq_hw_number_t hwirq)
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{
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struct plic_priv *priv = d->host_data;
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irq_domain_set_info(d, irq, hwirq, &plic_chip, d->host_data,
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handle_fasteoi_irq, NULL, NULL);
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irq_set_noprobe(irq);
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irq_set_affinity(irq, &priv->lmask);
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return 0;
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}
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static int plic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
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unsigned int nr_irqs, void *arg)
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{
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int i, ret;
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irq_hw_number_t hwirq;
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unsigned int type;
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struct irq_fwspec *fwspec = arg;
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ret = irq_domain_translate_onecell(domain, fwspec, &hwirq, &type);
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if (ret)
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return ret;
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for (i = 0; i < nr_irqs; i++) {
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ret = plic_irqdomain_map(domain, virq + i, hwirq + i);
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if (ret)
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return ret;
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}
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return 0;
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}
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static const struct irq_domain_ops plic_irqdomain_ops = {
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.translate = irq_domain_translate_onecell,
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.alloc = plic_irq_domain_alloc,
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.free = irq_domain_free_irqs_top,
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};
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/*
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* Handling an interrupt is a two-step process: first you claim the interrupt
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* by reading the claim register, then you complete the interrupt by writing
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* that source ID back to the same claim register. This automatically enables
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* and disables the interrupt, so there's nothing else to do.
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*/
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static void plic_handle_irq(struct irq_desc *desc)
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{
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struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
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struct irq_chip *chip = irq_desc_get_chip(desc);
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void __iomem *claim = handler->hart_base + CONTEXT_CLAIM;
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irq_hw_number_t hwirq;
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WARN_ON_ONCE(!handler->present);
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chained_irq_enter(chip, desc);
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while ((hwirq = readl(claim))) {
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int err = generic_handle_domain_irq(handler->priv->irqdomain,
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hwirq);
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if (unlikely(err))
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pr_warn_ratelimited("can't find mapping for hwirq %lu\n",
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hwirq);
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}
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chained_irq_exit(chip, desc);
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}
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static void plic_set_threshold(struct plic_handler *handler, u32 threshold)
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{
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/* priority must be > threshold to trigger an interrupt */
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writel(threshold, handler->hart_base + CONTEXT_THRESHOLD);
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}
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static int plic_dying_cpu(unsigned int cpu)
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{
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if (plic_parent_irq)
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disable_percpu_irq(plic_parent_irq);
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return 0;
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}
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static int plic_starting_cpu(unsigned int cpu)
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{
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struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
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if (plic_parent_irq)
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enable_percpu_irq(plic_parent_irq,
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irq_get_trigger_type(plic_parent_irq));
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else
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pr_warn("cpu%d: parent irq not available\n", cpu);
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plic_set_threshold(handler, PLIC_ENABLE_THRESHOLD);
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return 0;
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}
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static int __init plic_init(struct device_node *node,
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struct device_node *parent)
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{
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int error = 0, nr_contexts, nr_handlers = 0, i;
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u32 nr_irqs;
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struct plic_priv *priv;
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struct plic_handler *handler;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->regs = of_iomap(node, 0);
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if (WARN_ON(!priv->regs)) {
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error = -EIO;
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goto out_free_priv;
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}
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error = -EINVAL;
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of_property_read_u32(node, "riscv,ndev", &nr_irqs);
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if (WARN_ON(!nr_irqs))
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goto out_iounmap;
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nr_contexts = of_irq_count(node);
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if (WARN_ON(!nr_contexts))
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goto out_iounmap;
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error = -ENOMEM;
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priv->irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
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&plic_irqdomain_ops, priv);
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if (WARN_ON(!priv->irqdomain))
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goto out_iounmap;
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for (i = 0; i < nr_contexts; i++) {
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struct of_phandle_args parent;
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irq_hw_number_t hwirq;
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int cpu, hartid;
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if (of_irq_parse_one(node, i, &parent)) {
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pr_err("failed to parse parent for context %d.\n", i);
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continue;
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}
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/*
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* Skip contexts other than external interrupts for our
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* privilege level.
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*/
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if (parent.args[0] != RV_IRQ_EXT)
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continue;
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hartid = riscv_of_parent_hartid(parent.np);
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if (hartid < 0) {
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pr_warn("failed to parse hart ID for context %d.\n", i);
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continue;
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}
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cpu = riscv_hartid_to_cpuid(hartid);
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if (cpu < 0) {
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pr_warn("Invalid cpuid for context %d\n", i);
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continue;
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}
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/* Find parent domain and register chained handler */
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if (!plic_parent_irq && irq_find_host(parent.np)) {
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plic_parent_irq = irq_of_parse_and_map(node, i);
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if (plic_parent_irq)
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irq_set_chained_handler(plic_parent_irq,
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plic_handle_irq);
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}
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/*
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* When running in M-mode we need to ignore the S-mode handler.
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* Here we assume it always comes later, but that might be a
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* little fragile.
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*/
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handler = per_cpu_ptr(&plic_handlers, cpu);
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if (handler->present) {
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pr_warn("handler already present for context %d.\n", i);
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plic_set_threshold(handler, PLIC_DISABLE_THRESHOLD);
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goto done;
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}
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cpumask_set_cpu(cpu, &priv->lmask);
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handler->present = true;
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handler->hart_base =
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priv->regs + CONTEXT_BASE + i * CONTEXT_PER_HART;
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raw_spin_lock_init(&handler->enable_lock);
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handler->enable_base =
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priv->regs + ENABLE_BASE + i * ENABLE_PER_HART;
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handler->priv = priv;
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done:
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for (hwirq = 1; hwirq <= nr_irqs; hwirq++)
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plic_toggle(handler, hwirq, 0);
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nr_handlers++;
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}
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/*
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* We can have multiple PLIC instances so setup cpuhp state only
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* when context handler for current/boot CPU is present.
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*/
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handler = this_cpu_ptr(&plic_handlers);
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if (handler->present && !plic_cpuhp_setup_done) {
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cpuhp_setup_state(CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
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"irqchip/sifive/plic:starting",
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plic_starting_cpu, plic_dying_cpu);
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plic_cpuhp_setup_done = true;
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}
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pr_info("%pOFP: mapped %d interrupts with %d handlers for"
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" %d contexts.\n", node, nr_irqs, nr_handlers, nr_contexts);
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return 0;
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out_iounmap:
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iounmap(priv->regs);
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out_free_priv:
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kfree(priv);
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return error;
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}
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IRQCHIP_DECLARE(sifive_plic, "sifive,plic-1.0.0", plic_init);
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IRQCHIP_DECLARE(riscv_plic0, "riscv,plic0", plic_init); /* for legacy systems */
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