irqchip: Add per-cpu interrupt partitioning library
We've unfortunately started seeing a situation where percpu interrupts are partitioned in the system: one arbitrary set of CPUs has an interrupt connected to a type of device, while another disjoint set of CPUs has the same interrupt connected to another type of device. This makes it impossible to have a device driver requesting this interrupt using the current percpu-interrupt abstraction, as the same interrupt number is now potentially claimed by at least two drivers, and we forbid interrupt sharing on per-cpu interrupt. A solution to this is to turn things upside down. Let's assume that our system describes all the possible partitions for a given interrupt, and give each of them a unique identifier. It is then possible to create a namespace where the affinity identifier itself is a form of interrupt number. At this point, it becomes easy to implement a set of partitions as a cascaded irqchip, each affinity identifier being the HW irq. This allows us to keep a number of nice properties: - Each partition results in a separate percpu-interrupt (with a restrictied affinity), which keeps drivers happy. - Because the underlying interrupt is still per-cpu, the overhead of the indirection can be kept pretty minimal. - The core code can ignore most of that crap. For that purpose, we implement a small library that deals with some of the boilerplate code, relying on platform-specific drivers to provide a description of the affinity sets and a set of callbacks. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: devicetree@vger.kernel.org Cc: Jason Cooper <jason@lakedaemon.net> Cc: Will Deacon <will.deacon@arm.com> Cc: Rob Herring <robh+dt@kernel.org> Link: http://lkml.kernel.org/r/1460365075-7316-4-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>steinar/wifi_calib_4_9_kernel
Marc Zyngier
Thomas Gleixner
parent
222df54fd8
commit
9e2c986cb4
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@ -244,3 +244,6 @@ config IRQ_MXS
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config MVEBU_ODMI
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bool
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select GENERIC_MSI_IRQ_DOMAIN
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config PARTITION_PERCPU
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bool
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@ -27,6 +27,7 @@ obj-$(CONFIG_REALVIEW_DT) += irq-gic-realview.o
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obj-$(CONFIG_ARM_GIC_V2M) += irq-gic-v2m.o
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obj-$(CONFIG_ARM_GIC_V3) += irq-gic-v3.o irq-gic-common.o
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obj-$(CONFIG_ARM_GIC_V3_ITS) += irq-gic-v3-its.o irq-gic-v3-its-pci-msi.o irq-gic-v3-its-platform-msi.o
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obj-$(CONFIG_PARTITION_PERCPU) += irq-partition-percpu.o
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obj-$(CONFIG_HISILICON_IRQ_MBIGEN) += irq-mbigen.o
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obj-$(CONFIG_ARM_NVIC) += irq-nvic.o
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obj-$(CONFIG_ARM_VIC) += irq-vic.o
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@ -0,0 +1,256 @@
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/*
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* Copyright (C) 2016 ARM Limited, All Rights Reserved.
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/bitops.h>
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#include <linux/interrupt.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/irqchip/irq-partition-percpu.h>
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#include <linux/irqdomain.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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struct partition_desc {
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int nr_parts;
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struct partition_affinity *parts;
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struct irq_domain *domain;
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struct irq_desc *chained_desc;
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unsigned long *bitmap;
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struct irq_domain_ops ops;
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};
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static bool partition_check_cpu(struct partition_desc *part,
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unsigned int cpu, unsigned int hwirq)
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{
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return cpumask_test_cpu(cpu, &part->parts[hwirq].mask);
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}
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static void partition_irq_mask(struct irq_data *d)
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{
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struct partition_desc *part = irq_data_get_irq_chip_data(d);
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struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
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struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
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if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
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chip->irq_mask)
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chip->irq_mask(data);
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}
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static void partition_irq_unmask(struct irq_data *d)
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{
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struct partition_desc *part = irq_data_get_irq_chip_data(d);
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struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
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struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
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if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
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chip->irq_unmask)
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chip->irq_unmask(data);
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}
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static int partition_irq_set_irqchip_state(struct irq_data *d,
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enum irqchip_irq_state which,
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bool val)
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{
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struct partition_desc *part = irq_data_get_irq_chip_data(d);
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struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
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struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
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if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
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chip->irq_set_irqchip_state)
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return chip->irq_set_irqchip_state(data, which, val);
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return -EINVAL;
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}
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static int partition_irq_get_irqchip_state(struct irq_data *d,
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enum irqchip_irq_state which,
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bool *val)
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{
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struct partition_desc *part = irq_data_get_irq_chip_data(d);
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struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
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struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
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if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
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chip->irq_get_irqchip_state)
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return chip->irq_get_irqchip_state(data, which, val);
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return -EINVAL;
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}
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static int partition_irq_set_type(struct irq_data *d, unsigned int type)
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{
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struct partition_desc *part = irq_data_get_irq_chip_data(d);
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struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
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struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
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if (chip->irq_set_type)
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return chip->irq_set_type(data, type);
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return -EINVAL;
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}
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static void partition_irq_print_chip(struct irq_data *d, struct seq_file *p)
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{
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struct partition_desc *part = irq_data_get_irq_chip_data(d);
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struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
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struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
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seq_printf(p, " %5s-%lu", chip->name, data->hwirq);
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}
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static struct irq_chip partition_irq_chip = {
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.irq_mask = partition_irq_mask,
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.irq_unmask = partition_irq_unmask,
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.irq_set_type = partition_irq_set_type,
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.irq_get_irqchip_state = partition_irq_get_irqchip_state,
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.irq_set_irqchip_state = partition_irq_set_irqchip_state,
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.irq_print_chip = partition_irq_print_chip,
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};
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static void partition_handle_irq(struct irq_desc *desc)
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{
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struct partition_desc *part = irq_desc_get_handler_data(desc);
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struct irq_chip *chip = irq_desc_get_chip(desc);
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int cpu = smp_processor_id();
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int hwirq;
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chained_irq_enter(chip, desc);
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for_each_set_bit(hwirq, part->bitmap, part->nr_parts) {
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if (partition_check_cpu(part, cpu, hwirq))
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break;
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}
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if (unlikely(hwirq == part->nr_parts)) {
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handle_bad_irq(desc);
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} else {
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unsigned int irq;
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irq = irq_find_mapping(part->domain, hwirq);
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generic_handle_irq(irq);
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}
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chained_irq_exit(chip, desc);
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}
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static int partition_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 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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struct partition_desc *part;
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BUG_ON(nr_irqs != 1);
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ret = domain->ops->translate(domain, fwspec, &hwirq, &type);
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if (ret)
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return ret;
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part = domain->host_data;
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set_bit(hwirq, part->bitmap);
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irq_set_chained_handler_and_data(irq_desc_get_irq(part->chained_desc),
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partition_handle_irq, part);
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irq_set_percpu_devid_partition(virq, &part->parts[hwirq].mask);
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irq_domain_set_info(domain, virq, hwirq, &partition_irq_chip, part,
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handle_percpu_devid_irq, NULL, NULL);
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irq_set_status_flags(virq, IRQ_NOAUTOEN);
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return 0;
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}
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static void partition_domain_free(struct irq_domain *domain, unsigned int virq,
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unsigned int nr_irqs)
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{
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struct irq_data *d;
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BUG_ON(nr_irqs != 1);
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d = irq_domain_get_irq_data(domain, virq);
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irq_set_handler(virq, NULL);
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irq_domain_reset_irq_data(d);
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}
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int partition_translate_id(struct partition_desc *desc, void *partition_id)
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{
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struct partition_affinity *part = NULL;
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int i;
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for (i = 0; i < desc->nr_parts; i++) {
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if (desc->parts[i].partition_id == partition_id) {
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part = &desc->parts[i];
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break;
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}
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}
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if (WARN_ON(!part)) {
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pr_err("Failed to find partition\n");
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return -EINVAL;
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}
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return i;
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}
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struct partition_desc *partition_create_desc(struct fwnode_handle *fwnode,
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struct partition_affinity *parts,
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int nr_parts,
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int chained_irq,
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const struct irq_domain_ops *ops)
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{
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struct partition_desc *desc;
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struct irq_domain *d;
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BUG_ON(!ops->select || !ops->translate);
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desc = kzalloc(sizeof(*desc), GFP_KERNEL);
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if (!desc)
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return NULL;
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desc->ops = *ops;
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desc->ops.free = partition_domain_free;
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desc->ops.alloc = partition_domain_alloc;
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d = irq_domain_create_linear(fwnode, nr_parts, &desc->ops, desc);
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if (!d)
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goto out;
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desc->domain = d;
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desc->bitmap = kzalloc(sizeof(long) * BITS_TO_LONGS(nr_parts),
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GFP_KERNEL);
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if (WARN_ON(!desc->bitmap))
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goto out;
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desc->chained_desc = irq_to_desc(chained_irq);
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desc->nr_parts = nr_parts;
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desc->parts = parts;
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return desc;
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out:
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if (d)
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irq_domain_remove(d);
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kfree(desc);
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return NULL;
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}
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struct irq_domain *partition_get_domain(struct partition_desc *dsc)
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{
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if (dsc)
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return dsc->domain;
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return NULL;
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}
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@ -0,0 +1,59 @@
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/*
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* Copyright (C) 2016 ARM Limited, All Rights Reserved.
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/fwnode.h>
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#include <linux/cpumask.h>
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#include <linux/irqdomain.h>
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struct partition_affinity {
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cpumask_t mask;
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void *partition_id;
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};
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struct partition_desc;
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#ifdef CONFIG_PARTITION_PERCPU
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int partition_translate_id(struct partition_desc *desc, void *partition_id);
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struct partition_desc *partition_create_desc(struct fwnode_handle *fwnode,
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struct partition_affinity *parts,
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int nr_parts,
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int chained_irq,
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const struct irq_domain_ops *ops);
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struct irq_domain *partition_get_domain(struct partition_desc *dsc);
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#else
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static inline int partition_translate_id(struct partition_desc *desc,
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void *partition_id)
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{
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return -EINVAL;
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}
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static inline
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struct partition_desc *partition_create_desc(struct fwnode_handle *fwnode,
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struct partition_affinity *parts,
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int nr_parts,
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int chained_irq,
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const struct irq_domain_ops *ops)
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{
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return NULL;
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}
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static inline
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struct irq_domain *partition_get_domain(struct partition_desc *dsc)
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{
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return NULL;
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}
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#endif
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