On 19/07/17 14:58, Thomas Gleixner wrote: > On Wed, 19 Jul 2017, Bartosz Golaszewski wrote: > >> 2017-07-19 14:25 GMT+02:00 Thomas Gleixner <tglx@xxxxxxxxxxxxx>: >>> On Wed, 19 Jul 2017, Bartosz Golaszewski wrote: >>> >>>> Some frameworks (e.g. iio, gpiolib) use irq_work to implement simulated >>>> interrupts that can be 'fired' from process context when needed and >>>> requested just like normal interrupts. This is useful for testing and >>>> development purposes. >>>> >>>> Currently this code is reimplemented by every user. This series >>>> proposes to add a new set of functions that can be used by drivers >>>> that want to simulate interrupts without having to duplicate any >>>> boilerplate code. >>>> >>>> The first patch adds a simple irq simulator framework. The second >>>> extends it with resource management. The third uses the new >>>> functionality in the gpio-mockup testing driver. >>>> >>>> NOTE: The next candidate for using this API would be iio-dummy-evgen. >>> >>> I like the general idea - have not looked at the code yet. Just a quick >>> question: How many copies/variants of this scheme do we have in tree? >>> >>> Thanks, >>> >>> tglx >> >> Currently there are two: iio and gpiolib basically duplicate the same >> code in their respective testing drivers. I only used irq_sim in >> gpio-mockup in this series as an example and to see if there's any >> interest in merging it before spending time on iio-dummy-evgen. > > Yes, I think so. Consolidation is always a good thing and simulation is > useful for developing or validating code. Indeed, that's pretty interesting. On a slightly tangential subject, there is another aspect that I thought of implementing for a while, but always ended up just relying on a quick hack: forcing the injection of an actual interrupt. A number of interrupt controllers have the ability to make an interrupt pending, for it to be handled as if a device had actually triggered it. In my case, it has proved to be incredibly useful when debugging the interrupt controller itself, and also things that mess with interrupts in a creative way (like KVM) while relying on a particular interrupt controller. What I had in mind was something like: echo 1 >/proc/irq/9/trigger (or the corresponding /sys/kernel/debug/irq/irqs/ interface if we want to make sure that this is really not for production use...). If there is any interest, I'll try to whip something up. Thanks, M. -- Jazz is not dead. It just smells funny... -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
