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340 lines
9.2 KiB
340 lines
9.2 KiB
/*
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* linux/kernel/irq/ipi.c
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*
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* Copyright (C) 2015 Imagination Technologies Ltd
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* Author: Qais Yousef <qais.yousef@imgtec.com>
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*
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* This file contains driver APIs to the IPI subsystem.
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*/
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#define pr_fmt(fmt) "genirq/ipi: " fmt
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#include <linux/irqdomain.h>
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#include <linux/irq.h>
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/**
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* irq_reserve_ipi() - Setup an IPI to destination cpumask
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* @domain: IPI domain
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* @dest: cpumask of cpus which can receive the IPI
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*
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* Allocate a virq that can be used to send IPI to any CPU in dest mask.
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*
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* On success it'll return linux irq number and error code on failure
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*/
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int irq_reserve_ipi(struct irq_domain *domain,
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const struct cpumask *dest)
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{
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unsigned int nr_irqs, offset;
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struct irq_data *data;
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int virq, i;
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if (!domain ||!irq_domain_is_ipi(domain)) {
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pr_warn("Reservation on a non IPI domain\n");
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return -EINVAL;
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}
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if (!cpumask_subset(dest, cpu_possible_mask)) {
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pr_warn("Reservation is not in possible_cpu_mask\n");
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return -EINVAL;
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}
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nr_irqs = cpumask_weight(dest);
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if (!nr_irqs) {
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pr_warn("Reservation for empty destination mask\n");
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return -EINVAL;
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}
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if (irq_domain_is_ipi_single(domain)) {
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/*
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* If the underlying implementation uses a single HW irq on
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* all cpus then we only need a single Linux irq number for
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* it. We have no restrictions vs. the destination mask. The
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* underlying implementation can deal with holes nicely.
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*/
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nr_irqs = 1;
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offset = 0;
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} else {
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unsigned int next;
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/*
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* The IPI requires a seperate HW irq on each CPU. We require
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* that the destination mask is consecutive. If an
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* implementation needs to support holes, it can reserve
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* several IPI ranges.
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*/
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offset = cpumask_first(dest);
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/*
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* Find a hole and if found look for another set bit after the
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* hole. For now we don't support this scenario.
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*/
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next = cpumask_next_zero(offset, dest);
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if (next < nr_cpu_ids)
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next = cpumask_next(next, dest);
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if (next < nr_cpu_ids) {
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pr_warn("Destination mask has holes\n");
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return -EINVAL;
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}
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}
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virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE, NULL);
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if (virq <= 0) {
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pr_warn("Can't reserve IPI, failed to alloc descs\n");
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return -ENOMEM;
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}
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virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
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(void *) dest, true, NULL);
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if (virq <= 0) {
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pr_warn("Can't reserve IPI, failed to alloc hw irqs\n");
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goto free_descs;
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}
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for (i = 0; i < nr_irqs; i++) {
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data = irq_get_irq_data(virq + i);
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cpumask_copy(data->common->affinity, dest);
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data->common->ipi_offset = offset;
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irq_set_status_flags(virq + i, IRQ_NO_BALANCING);
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}
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return virq;
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free_descs:
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irq_free_descs(virq, nr_irqs);
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return -EBUSY;
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}
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/**
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* irq_destroy_ipi() - unreserve an IPI that was previously allocated
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* @irq: linux irq number to be destroyed
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* @dest: cpumask of cpus which should have the IPI removed
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*
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* The IPIs allocated with irq_reserve_ipi() are retuerned to the system
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* destroying all virqs associated with them.
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*
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* Return 0 on success or error code on failure.
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*/
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int irq_destroy_ipi(unsigned int irq, const struct cpumask *dest)
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{
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struct irq_data *data = irq_get_irq_data(irq);
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struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
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struct irq_domain *domain;
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unsigned int nr_irqs;
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if (!irq || !data || !ipimask)
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return -EINVAL;
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domain = data->domain;
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if (WARN_ON(domain == NULL))
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return -EINVAL;
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if (!irq_domain_is_ipi(domain)) {
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pr_warn("Trying to destroy a non IPI domain!\n");
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return -EINVAL;
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}
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if (WARN_ON(!cpumask_subset(dest, ipimask)))
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/*
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* Must be destroying a subset of CPUs to which this IPI
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* was set up to target
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*/
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return -EINVAL;
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if (irq_domain_is_ipi_per_cpu(domain)) {
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irq = irq + cpumask_first(dest) - data->common->ipi_offset;
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nr_irqs = cpumask_weight(dest);
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} else {
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nr_irqs = 1;
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}
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irq_domain_free_irqs(irq, nr_irqs);
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return 0;
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}
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/**
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* ipi_get_hwirq - Get the hwirq associated with an IPI to a cpu
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* @irq: linux irq number
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* @cpu: the target cpu
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*
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* When dealing with coprocessors IPI, we need to inform the coprocessor of
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* the hwirq it needs to use to receive and send IPIs.
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*
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* Returns hwirq value on success and INVALID_HWIRQ on failure.
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*/
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irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu)
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{
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struct irq_data *data = irq_get_irq_data(irq);
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struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
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if (!data || !ipimask || cpu >= nr_cpu_ids)
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return INVALID_HWIRQ;
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if (!cpumask_test_cpu(cpu, ipimask))
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return INVALID_HWIRQ;
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/*
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* Get the real hardware irq number if the underlying implementation
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* uses a seperate irq per cpu. If the underlying implementation uses
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* a single hardware irq for all cpus then the IPI send mechanism
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* needs to take care of the cpu destinations.
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*/
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if (irq_domain_is_ipi_per_cpu(data->domain))
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data = irq_get_irq_data(irq + cpu - data->common->ipi_offset);
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return data ? irqd_to_hwirq(data) : INVALID_HWIRQ;
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}
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EXPORT_SYMBOL_GPL(ipi_get_hwirq);
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static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data,
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const struct cpumask *dest, unsigned int cpu)
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{
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struct cpumask *ipimask = irq_data_get_affinity_mask(data);
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if (!chip || !ipimask)
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return -EINVAL;
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if (!chip->ipi_send_single && !chip->ipi_send_mask)
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return -EINVAL;
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if (cpu >= nr_cpu_ids)
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return -EINVAL;
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if (dest) {
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if (!cpumask_subset(dest, ipimask))
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return -EINVAL;
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} else {
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if (!cpumask_test_cpu(cpu, ipimask))
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return -EINVAL;
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}
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return 0;
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}
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/**
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* __ipi_send_single - send an IPI to a target Linux SMP CPU
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* @desc: pointer to irq_desc of the IRQ
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* @cpu: destination CPU, must in the destination mask passed to
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* irq_reserve_ipi()
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*
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* This function is for architecture or core code to speed up IPI sending. Not
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* usable from driver code.
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*
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* Returns zero on success and negative error number on failure.
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*/
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int __ipi_send_single(struct irq_desc *desc, unsigned int cpu)
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{
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struct irq_data *data = irq_desc_get_irq_data(desc);
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struct irq_chip *chip = irq_data_get_irq_chip(data);
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#ifdef DEBUG
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/*
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* Minimise the overhead by omitting the checks for Linux SMP IPIs.
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* Since the callers should be arch or core code which is generally
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* trusted, only check for errors when debugging.
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*/
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if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
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return -EINVAL;
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#endif
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if (!chip->ipi_send_single) {
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chip->ipi_send_mask(data, cpumask_of(cpu));
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return 0;
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}
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/* FIXME: Store this information in irqdata flags */
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if (irq_domain_is_ipi_per_cpu(data->domain) &&
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cpu != data->common->ipi_offset) {
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/* use the correct data for that cpu */
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unsigned irq = data->irq + cpu - data->common->ipi_offset;
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data = irq_get_irq_data(irq);
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}
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chip->ipi_send_single(data, cpu);
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return 0;
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}
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/**
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* ipi_send_mask - send an IPI to target Linux SMP CPU(s)
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* @desc: pointer to irq_desc of the IRQ
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* @dest: dest CPU(s), must be a subset of the mask passed to
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* irq_reserve_ipi()
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*
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* This function is for architecture or core code to speed up IPI sending. Not
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* usable from driver code.
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*
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* Returns zero on success and negative error number on failure.
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*/
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int __ipi_send_mask(struct irq_desc *desc, const struct cpumask *dest)
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{
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struct irq_data *data = irq_desc_get_irq_data(desc);
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struct irq_chip *chip = irq_data_get_irq_chip(data);
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unsigned int cpu;
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#ifdef DEBUG
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/*
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* Minimise the overhead by omitting the checks for Linux SMP IPIs.
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* Since the callers should be arch or core code which is generally
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* trusted, only check for errors when debugging.
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*/
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if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
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return -EINVAL;
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#endif
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if (chip->ipi_send_mask) {
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chip->ipi_send_mask(data, dest);
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return 0;
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}
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if (irq_domain_is_ipi_per_cpu(data->domain)) {
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unsigned int base = data->irq;
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for_each_cpu(cpu, dest) {
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unsigned irq = base + cpu - data->common->ipi_offset;
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data = irq_get_irq_data(irq);
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chip->ipi_send_single(data, cpu);
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}
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} else {
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for_each_cpu(cpu, dest)
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chip->ipi_send_single(data, cpu);
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}
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return 0;
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}
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/**
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* ipi_send_single - Send an IPI to a single CPU
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* @virq: linux irq number from irq_reserve_ipi()
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* @cpu: destination CPU, must in the destination mask passed to
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* irq_reserve_ipi()
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*
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* Returns zero on success and negative error number on failure.
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*/
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int ipi_send_single(unsigned int virq, unsigned int cpu)
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{
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struct irq_desc *desc = irq_to_desc(virq);
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struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
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struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
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if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
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return -EINVAL;
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return __ipi_send_single(desc, cpu);
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}
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EXPORT_SYMBOL_GPL(ipi_send_single);
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/**
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* ipi_send_mask - Send an IPI to target CPU(s)
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* @virq: linux irq number from irq_reserve_ipi()
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* @dest: dest CPU(s), must be a subset of the mask passed to
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* irq_reserve_ipi()
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*
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* Returns zero on success and negative error number on failure.
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*/
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int ipi_send_mask(unsigned int virq, const struct cpumask *dest)
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{
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struct irq_desc *desc = irq_to_desc(virq);
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struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
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struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
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if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
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return -EINVAL;
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return __ipi_send_mask(desc, dest);
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}
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EXPORT_SYMBOL_GPL(ipi_send_mask);
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