genirq: Add a new generic IPI reservation code to irq core

Add a generic mechanism to dynamically allocate an IPI. Depending on the
underlying implementation this creates either a single Linux irq or a
consective range of Linux irqs. The Linux irq is used later to send IPIs to
other CPUs.

[ tglx: Massaged the code and removed the 'consecutive mask' restriction for
  	the single IRQ case ]

Signed-off-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: <jason@lakedaemon.net>
Cc: <marc.zyngier@arm.com>
Cc: <jiang.liu@linux.intel.com>
Cc: <ralf@linux-mips.org>
Cc: <linux-mips@linux-mips.org>
Cc: <lisa.parratt@imgtec.com>
Cc: Qais Yousef <qsyousef@gmail.com>
Link: http://lkml.kernel.org/r/1449580830-23652-9-git-send-email-qais.yousef@imgtec.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Qais Yousef 2015-12-08 13:20:19 +00:00 committed by Thomas Gleixner
parent ac0a0cd266
commit d17bf24e69
4 changed files with 146 additions and 0 deletions

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@ -940,4 +940,7 @@ static inline u32 irq_reg_readl(struct irq_chip_generic *gc,
return readl(gc->reg_base + reg_offset);
}
/* Contrary to Linux irqs, for hardware irqs the irq number 0 is valid */
#define INVALID_HWIRQ (~0UL)
#endif /* _LINUX_IRQ_H */

View File

@ -344,6 +344,11 @@ int irq_domain_xlate_onetwocell(struct irq_domain *d, struct device_node *ctrlr,
const u32 *intspec, unsigned int intsize,
irq_hw_number_t *out_hwirq, unsigned int *out_type);
/* IPI functions */
unsigned int irq_reserve_ipi(struct irq_domain *domain,
const struct cpumask *dest);
void irq_destroy_ipi(unsigned int irq);
/* V2 interfaces to support hierarchy IRQ domains. */
extern struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
unsigned int virq);

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@ -8,3 +8,4 @@ obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o
obj-$(CONFIG_PM_SLEEP) += pm.o
obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o

137
kernel/irq/ipi.c Normal file
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@ -0,0 +1,137 @@
/*
* linux/kernel/irq/ipi.c
*
* Copyright (C) 2015 Imagination Technologies Ltd
* Author: Qais Yousef <qais.yousef@imgtec.com>
*
* This file contains driver APIs to the IPI subsystem.
*/
#define pr_fmt(fmt) "genirq/ipi: " fmt
#include <linux/irqdomain.h>
#include <linux/irq.h>
/**
* irq_reserve_ipi() - Setup an IPI to destination cpumask
* @domain: IPI domain
* @dest: cpumask of cpus which can receive the IPI
*
* Allocate a virq that can be used to send IPI to any CPU in dest mask.
*
* On success it'll return linux irq number and 0 on failure
*/
unsigned int irq_reserve_ipi(struct irq_domain *domain,
const struct cpumask *dest)
{
unsigned int nr_irqs, offset;
struct irq_data *data;
int virq, i;
if (!domain ||!irq_domain_is_ipi(domain)) {
pr_warn("Reservation on a non IPI domain\n");
return 0;
}
if (!cpumask_subset(dest, cpu_possible_mask)) {
pr_warn("Reservation is not in possible_cpu_mask\n");
return 0;
}
nr_irqs = cpumask_weight(dest);
if (!nr_irqs) {
pr_warn("Reservation for empty destination mask\n");
return 0;
}
if (irq_domain_is_ipi_single(domain)) {
/*
* If the underlying implementation uses a single HW irq on
* all cpus then we only need a single Linux irq number for
* it. We have no restrictions vs. the destination mask. The
* underlying implementation can deal with holes nicely.
*/
nr_irqs = 1;
offset = 0;
} else {
unsigned int next;
/*
* The IPI requires a seperate HW irq on each CPU. We require
* that the destination mask is consecutive. If an
* implementation needs to support holes, it can reserve
* several IPI ranges.
*/
offset = cpumask_first(dest);
/*
* Find a hole and if found look for another set bit after the
* hole. For now we don't support this scenario.
*/
next = cpumask_next_zero(offset, dest);
if (next < nr_cpu_ids)
next = cpumask_next(next, dest);
if (next < nr_cpu_ids) {
pr_warn("Destination mask has holes\n");
return 0;
}
}
virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE);
if (virq <= 0) {
pr_warn("Can't reserve IPI, failed to alloc descs\n");
return 0;
}
virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
(void *) dest, true);
if (virq <= 0) {
pr_warn("Can't reserve IPI, failed to alloc hw irqs\n");
goto free_descs;
}
for (i = 0; i < nr_irqs; i++) {
data = irq_get_irq_data(virq + i);
cpumask_copy(data->common->affinity, dest);
data->common->ipi_offset = offset;
}
return virq;
free_descs:
irq_free_descs(virq, nr_irqs);
return 0;
}
/**
* irq_destroy_ipi() - unreserve an IPI that was previously allocated
* @irq: linux irq number to be destroyed
*
* Return the IPIs allocated with irq_reserve_ipi() to the system destroying
* all virqs associated with them.
*/
void irq_destroy_ipi(unsigned int irq)
{
struct irq_data *data = irq_get_irq_data(irq);
struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
struct irq_domain *domain;
unsigned int nr_irqs;
if (!irq || !data || !ipimask)
return;
domain = data->domain;
if (WARN_ON(domain == NULL))
return;
if (!irq_domain_is_ipi(domain)) {
pr_warn("Trying to destroy a non IPI domain!\n");
return;
}
if (irq_domain_is_ipi_per_cpu(domain))
nr_irqs = cpumask_weight(ipimask);
else
nr_irqs = 1;
irq_domain_free_irqs(irq, nr_irqs);
}