linux/Documentation/ABI/testing/sysfs-kernel-irq
Craig Gallek ecb3f394c5 genirq: Expose interrupt information through sysfs
Information about interrupts is exposed via /proc/interrupts, but the
format of that file has changed over kernel versions and differs across
architectures. It also has varying column numbers depending on hardware.

That all makes it hard for tools to parse.

To solve this, expose the information through sysfs so each irq attribute
is in a separate file in a consistent, machine parsable way.

This feature is only available when both CONFIG_SPARSE_IRQ and
CONFIG_SYSFS are enabled.

Examples:
  /sys/kernel/irq/18/actions:	i801_smbus,ehci_hcd:usb1,uhci_hcd:usb7
  /sys/kernel/irq/18/chip_name:	IR-IO-APIC
  /sys/kernel/irq/18/hwirq:		18
  /sys/kernel/irq/18/name:		fasteoi
  /sys/kernel/irq/18/per_cpu_count:	0,0
  /sys/kernel/irq/18/type:		level

  /sys/kernel/irq/25/actions:	ahci0
  /sys/kernel/irq/25/chip_name:	IR-PCI-MSI
  /sys/kernel/irq/25/hwirq:		512000
  /sys/kernel/irq/25/name:		edge
  /sys/kernel/irq/25/per_cpu_count:	29036,0
  /sys/kernel/irq/25/type:		edge

[ tglx: Moved kobject_del() under sparse_irq_lock, massaged code comments
  	and changelog ]

Signed-off-by: Craig Gallek <kraig@google.com>
Cc: David Decotigny <decot@google.com>
Link: http://lkml.kernel.org/r/1473783291-122873-1-git-send-email-kraigatgoog@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-14 15:28:15 +02:00

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What: /sys/kernel/irq
Date: September 2016
KernelVersion: 4.9
Contact: Craig Gallek <kraig@google.com>
Description: Directory containing information about the system's IRQs.
Specifically, data from the associated struct irq_desc.
The information here is similar to that in /proc/interrupts
but in a more machine-friendly format. This directory contains
one subdirectory for each Linux IRQ number.
What: /sys/kernel/irq/<irq>/actions
Date: September 2016
KernelVersion: 4.9
Contact: Craig Gallek <kraig@google.com>
Description: The IRQ action chain. A comma-separated list of zero or more
device names associated with this interrupt.
What: /sys/kernel/irq/<irq>/chip_name
Date: September 2016
KernelVersion: 4.9
Contact: Craig Gallek <kraig@google.com>
Description: Human-readable chip name supplied by the associated device
driver.
What: /sys/kernel/irq/<irq>/hwirq
Date: September 2016
KernelVersion: 4.9
Contact: Craig Gallek <kraig@google.com>
Description: When interrupt translation domains are used, this file contains
the underlying hardware IRQ number used for this Linux IRQ.
What: /sys/kernel/irq/<irq>/name
Date: September 2016
KernelVersion: 4.9
Contact: Craig Gallek <kraig@google.com>
Description: Human-readable flow handler name as defined by the irq chip
driver.
What: /sys/kernel/irq/<irq>/per_cpu_count
Date: September 2016
KernelVersion: 4.9
Contact: Craig Gallek <kraig@google.com>
Description: The number of times the interrupt has fired since boot. This
is a comma-separated list of counters; one per CPU in CPU id
order. NOTE: This file consistently shows counters for all
CPU ids. This differs from the behavior of /proc/interrupts
which only shows counters for online CPUs.
What: /sys/kernel/irq/<irq>/type
Date: September 2016
KernelVersion: 4.9
Contact: Craig Gallek <kraig@google.com>
Description: The type of the interrupt. Either the string 'level' or 'edge'.