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c024f06b3d
The J-Core AIC does not have separate interrupt numbers reserved for
cpu-local vs global interrupts. Instead, the driver requesting the irq
is expected to know whether its device uses per-cpu interrupts or not.
Previously it was assumed that handle_simple_irq could work for both
cases, but it intentionally drops interrupts for an irq number that
already has a handler running. This resulted in the timer interrupt
for one cpu being lost when multiple cpus' timers were set for
approximately the same expiration time, leading to stalls. In theory
the same could also happen with IPIs.
To solve the problem, instead of registering handle_simple_irq as the
handler, register a wrapper function which checks whether the irq to
be handled was requested as per-cpu or not, and passes it to
handle_simple_irq or handle_percpu_irq accordingly.
Fixes: 981b58f66c ("irqchip/jcore-aic: Add J-Core AIC driver")
Signed-off-by: Rich Felker <dalias@libc.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: linux-sh@vger.kernel.org
Link: http://lkml.kernel.org/r/f18cec30bc17e3f52e478dd9f6714bfab02f227f.1476390724.git.dalias@libc.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
114 lines
3.1 KiB
C
114 lines
3.1 KiB
C
/*
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* J-Core SoC AIC driver
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*
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* Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/irq.h>
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#include <linux/io.h>
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#include <linux/irqchip.h>
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#include <linux/irqdomain.h>
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#include <linux/cpu.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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#define JCORE_AIC_MAX_HWIRQ 127
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#define JCORE_AIC1_MIN_HWIRQ 16
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#define JCORE_AIC2_MIN_HWIRQ 64
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#define JCORE_AIC1_INTPRI_REG 8
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static struct irq_chip jcore_aic;
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/*
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* The J-Core AIC1 and AIC2 are cpu-local interrupt controllers and do
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* not distinguish or use distinct irq number ranges for per-cpu event
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* interrupts (timer, IPI). Since information to determine whether a
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* particular irq number should be treated as per-cpu is not available
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* at mapping time, we use a wrapper handler function which chooses
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* the right handler at runtime based on whether IRQF_PERCPU was used
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* when requesting the irq.
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*/
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static void handle_jcore_irq(struct irq_desc *desc)
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{
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if (irqd_is_per_cpu(irq_desc_get_irq_data(desc)))
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handle_percpu_irq(desc);
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else
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handle_simple_irq(desc);
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}
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static int jcore_aic_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 irq_chip *aic = d->host_data;
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irq_set_chip_and_handler(irq, aic, handle_jcore_irq);
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return 0;
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}
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static const struct irq_domain_ops jcore_aic_irqdomain_ops = {
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.map = jcore_aic_irqdomain_map,
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.xlate = irq_domain_xlate_onecell,
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};
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static void noop(struct irq_data *data)
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{
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}
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static int __init aic_irq_of_init(struct device_node *node,
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struct device_node *parent)
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{
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unsigned min_irq = JCORE_AIC2_MIN_HWIRQ;
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unsigned dom_sz = JCORE_AIC_MAX_HWIRQ+1;
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struct irq_domain *domain;
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pr_info("Initializing J-Core AIC\n");
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/* AIC1 needs priority initialization to receive interrupts. */
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if (of_device_is_compatible(node, "jcore,aic1")) {
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unsigned cpu;
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for_each_present_cpu(cpu) {
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void __iomem *base = of_iomap(node, cpu);
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if (!base) {
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pr_err("Unable to map AIC for cpu %u\n", cpu);
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return -ENOMEM;
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}
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__raw_writel(0xffffffff, base + JCORE_AIC1_INTPRI_REG);
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iounmap(base);
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}
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min_irq = JCORE_AIC1_MIN_HWIRQ;
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}
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/*
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* The irq chip framework requires either mask/unmask or enable/disable
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* function pointers to be provided, but the hardware does not have any
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* such mechanism; the only interrupt masking is at the cpu level and
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* it affects all interrupts. We provide dummy mask/unmask. The hardware
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* handles all interrupt control and clears pending status when the cpu
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* accepts the interrupt.
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*/
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jcore_aic.irq_mask = noop;
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jcore_aic.irq_unmask = noop;
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jcore_aic.name = "AIC";
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domain = irq_domain_add_linear(node, dom_sz, &jcore_aic_irqdomain_ops,
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&jcore_aic);
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if (!domain)
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return -ENOMEM;
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irq_create_strict_mappings(domain, min_irq, min_irq, dom_sz - min_irq);
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return 0;
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}
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IRQCHIP_DECLARE(jcore_aic2, "jcore,aic2", aic_irq_of_init);
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IRQCHIP_DECLARE(jcore_aic1, "jcore,aic1", aic_irq_of_init);
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