On 11/09/15 14:59, Cristina Opriceana wrote:
> Enhance interrupt generation in the dummy driver and expand its usage
> by introducing the irq_work infrastructure to trigger an interrupt.
>
> This way, the irq_work_queue() wrapper permits calling both of the top
> half and threaded part from a hard irq context, unlike handle_nested_irq(),
> which only calls the threaded part.
>
> As an outcome, the driver succeeds in simulating real hardware
> interrupts, while keeping the normal interrupt flow.
>
> Signed-off-by: Cristina Opriceana <cristina.opriceana@xxxxxxxxx>
Looks good to me. Will let this sit on the list for a little while
though to give others plenty of time to comment.
Thanks for doing this, ended up simpler than I thought it would
be which is always nice ;)
Jonathan
> ---
> Changes since v1:
> - keep irq_chip and the normal interrupt flow
> - run top half and threaded part from hardirq context
> - add demo function that registers current timestamp and uses it in the
> threaded interrupt handler
>
> drivers/staging/iio/iio_dummy_evgen.c | 26 +++++++++++++++++++++++++-
> drivers/staging/iio/iio_simple_dummy.h | 1 +
> drivers/staging/iio/iio_simple_dummy_events.c | 19 ++++++++++++++-----
> 3 files changed, 40 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/iio/iio_dummy_evgen.c b/drivers/staging/iio/iio_dummy_evgen.c
> index 6d38854..2bb4350 100644
> --- a/drivers/staging/iio/iio_dummy_evgen.c
> +++ b/drivers/staging/iio/iio_dummy_evgen.c
> @@ -24,9 +24,21 @@
> #include "iio_dummy_evgen.h"
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> +#include <linux/irq_work.h>
>
> /* Fiddly bit of faking and irq without hardware */
> #define IIO_EVENTGEN_NO 10
> +
> +/**
> + * struct iio_dummy_handle_irq - helper struct to simulate interrupt generation
> + * @work: irq_work used to run handlers from hardirq context
> + * @irq: fake irq line number to trigger an interrupt
> + */
> +struct iio_dummy_handle_irq {
> + struct irq_work work;
> + int irq;
> +};
> +
> /**
> * struct iio_dummy_evgen - evgen state
> * @chip: irq chip we are faking
> @@ -35,6 +47,7 @@
> * @inuse: mask of which irqs are connected
> * @regs: irq regs we are faking
> * @lock: protect the evgen state
> + * @handler: helper for a 'hardware-like' interrupt simulation
> */
> struct iio_dummy_eventgen {
> struct irq_chip chip;
> @@ -43,6 +56,7 @@ struct iio_dummy_eventgen {
> bool inuse[IIO_EVENTGEN_NO];
> struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
> struct mutex lock;
> + struct iio_dummy_handle_irq handler;
> };
>
> /* We can only ever have one instance of this 'device' */
> @@ -67,6 +81,14 @@ static void iio_dummy_event_irqunmask(struct irq_data *d)
> evgen->enabled[d->irq - evgen->base] = true;
> }
>
> +void iio_dummy_work_handler(struct irq_work *work)
> +{
> + struct iio_dummy_handle_irq *irq_handler;
> +
> + irq_handler = container_of(work, struct iio_dummy_handle_irq, work);
> + handle_simple_irq(irq_handler->irq, irq_to_desc(irq_handler->irq));
> +}
> +
> static int iio_dummy_evgen_create(void)
> {
> int ret, i;
> @@ -91,6 +113,7 @@ static int iio_dummy_evgen_create(void)
> IRQ_NOREQUEST | IRQ_NOAUTOEN,
> IRQ_NOPROBE);
> }
> + init_irq_work(&iio_evgen->handler.work, iio_dummy_work_handler);
> mutex_init(&iio_evgen->lock);
> return 0;
> }
> @@ -169,8 +192,9 @@ static ssize_t iio_evgen_poke(struct device *dev,
> iio_evgen->regs[this_attr->address].reg_id = this_attr->address;
> iio_evgen->regs[this_attr->address].reg_data = event;
>
> + iio_evgen->handler.irq = iio_evgen->base + this_attr->address;
> if (iio_evgen->enabled[this_attr->address])
> - handle_nested_irq(iio_evgen->base + this_attr->address);
> + irq_work_queue(&iio_evgen->handler.work);
>
> return len;
> }
> diff --git a/drivers/staging/iio/iio_simple_dummy.h b/drivers/staging/iio/iio_simple_dummy.h
> index 8d00224..5c2f4d0 100644
> --- a/drivers/staging/iio/iio_simple_dummy.h
> +++ b/drivers/staging/iio/iio_simple_dummy.h
> @@ -46,6 +46,7 @@ struct iio_dummy_state {
> int event_irq;
> int event_val;
> bool event_en;
> + s64 event_timestamp;
> #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
> };
>
> diff --git a/drivers/staging/iio/iio_simple_dummy_events.c b/drivers/staging/iio/iio_simple_dummy_events.c
> index 73108ba..bfbf1c5 100644
> --- a/drivers/staging/iio/iio_simple_dummy_events.c
> +++ b/drivers/staging/iio/iio_simple_dummy_events.c
> @@ -153,6 +153,15 @@ int iio_simple_dummy_write_event_value(struct iio_dev *indio_dev,
> return 0;
> }
>
> +static irqreturn_t iio_simple_dummy_get_timestamp(int irq, void *private)
> +{
> + struct iio_dev *indio_dev = private;
> + struct iio_dummy_state *st = iio_priv(indio_dev);
> +
> + st->event_timestamp = iio_get_time_ns();
> + return IRQ_HANDLED;
> +}
> +
> /**
> * iio_simple_dummy_event_handler() - identify and pass on event
> * @irq: irq of event line
> @@ -177,7 +186,7 @@ static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private)
> IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0,
> IIO_EV_DIR_RISING,
> IIO_EV_TYPE_THRESH, 0, 0, 0),
> - iio_get_time_ns());
> + st->event_timestamp);
> break;
> case 1:
> if (st->activity_running > st->event_val)
> @@ -187,7 +196,7 @@ static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private)
> IIO_EV_DIR_RISING,
> IIO_EV_TYPE_THRESH,
> 0, 0, 0),
> - iio_get_time_ns());
> + st->event_timestamp);
> break;
> case 2:
> if (st->activity_walking < st->event_val)
> @@ -197,14 +206,14 @@ static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private)
> IIO_EV_DIR_FALLING,
> IIO_EV_TYPE_THRESH,
> 0, 0, 0),
> - iio_get_time_ns());
> + st->event_timestamp);
> break;
> case 3:
> iio_push_event(indio_dev,
> IIO_EVENT_CODE(IIO_STEPS, 0, IIO_NO_MOD,
> IIO_EV_DIR_NONE,
> IIO_EV_TYPE_CHANGE, 0, 0, 0),
> - iio_get_time_ns());
> + st->event_timestamp);
> break;
> default:
> break;
> @@ -238,7 +247,7 @@ int iio_simple_dummy_events_register(struct iio_dev *indio_dev)
> st->regs = iio_dummy_evgen_get_regs(st->event_irq);
>
> ret = request_threaded_irq(st->event_irq,
> - NULL,
> + &iio_simple_dummy_get_timestamp,
> &iio_simple_dummy_event_handler,
> IRQF_ONESHOT,
> "iio_simple_event",
>
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