On 21/05/16 19:43, Linus Walleij wrote:
> commit 98ad8b41f58dff6b30713d7f09ae3834b8df7ded
> ("iio: st_sensors: verify interrupt event to status") caused
> a regression when reading ST sensors from a HRTimer trigger
> rather than the intrinsic interrupts: the HRTimer may
> trigger faster than the sensor provides new values, and
> as the check against new values available as a cause of
> the interrupt trigger was done in the poll function,
> this would bail out of the HRTimer interrupt with
> IRQ_NONE.
>
> So clearly we need to only check the new values available
> from the proper interrupt handler and not from the poll
> function, which should rather just read the raw values
> from the registers, put them into the buffer and be happy.
>
> To achieve this: switch the ST Sensors over to using a true
> threaded interrupt handler.
>
> In the interrupt thread, check if new values are available,
> else yield to the (potential) next device on the same
> interrupt line to check the registers. If the interrupt
> was ours, proceed to poll the values.
>
> Instead of relying on iio_trigger_generic_data_rdy_poll() as
> a top half to wake up the thread that polls the sensor for
> new data, have the thread call iio_trigger_poll_chained()
> after determining that is is the proper source of the
> interrupt. This is modelled on drivers/iio/accel/mma8452.c
> which is already using a properly threaded interrupt handler.
>
> In order to get the same precision in timestamps as
> previously, where samples would be timestamped in the
> poll function pf->timestamp when calling
> iio_trigger_generic_data_rdy_poll() we introduce a
> local timestamp in the sensor data, set it in the top half
> (fastpath) of the interrupt handler and provide that to the
> core when calling iio_push_to_buffers_with_timestamp().
>
> Additionally: if the active scanmask is not set for the
> sensor no IRQs should be enabled and we need to bail out
> with IRQ_NONE. This can happen if spurious IRQs fire when
> installing the threaded interrupt handler.
>
> Tested with hard interrupt triggers on LIS331DL, then also
> tested with hrtimers on the same sensor by creating a 75Hz
> HRTimer and using it to poll the sensor.
>
> Cc: Giuseppe Barba <giuseppe.barba@xxxxxx>
> Cc: Denis Ciocca <denis.ciocca@xxxxxx>
> Reported-by: Crestez Dan Leonard <cdleonard@xxxxxxxxx>
> Tested-by: Crestez Dan Leonard <cdleonard@xxxxxxxxx>
> Fixes: 97865fe41322 ("iio: st_sensors: verify interrupt event to status")
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
I've tested this as well now. Will let it sit for a few more days
as it won't make any difference until rc1 is out and may give
Denis / Giuseppe a chance to check it as well.
Works nicely.
Jonathan
> ---
> ChangeLog v6->v7:
> - Cut the higher bits of the status word explicitly and do not
> assume it to be masked by the .active_scan_mask[0].
> - NOTE: this patch is a regression fix and can be applied
> without 2/2. Hopefully this can go into v4.7-rc:s now.
> ChangeLog v5->v6:
> - Set the triggered buffer top half IRQ handler to NULL in all
> subdrivers (accelerometer, gyro, magnetometer, pressure) as
> we now use the iio_trigger_poll_chained() call.
> - Add st_sensors_validate_device() to the intrinsic triggers
> and set as .validate_deice() for all subdrivers. Its purpose
> is to check that the trigger is indeed provided by this
> device before we use it.
> ChangeLog v4->v5:
> - Move the setting of hw_irq_enabled to before the register
> write to enable interrupts so we avoid a race where this
> variable could be read in its previous state.
> ChangeLog v3->v4:
> - v3 would not timestamp properly when using a HRTimer to read
> values from the sensors. This is now fixed.
> - Add a flag to the sensor data indicating whether the hardware
> interrupt trigger is in use. If this is the case, we use that
> timestamp. If the hardware trigger is not in use, we just let
> the poll function read the current time before proceeding to
> grab the values from the sensor.
> - Move interrupt top/bottom halves to st_sensors_trigger.c so the
> interrupt code is kept together and easier to understand in
> context.
> ChangeLog v2->v3:
> - v2 was a total disaster, as iio_trigger_generic_data_rdy_poll()
> would just call the old bottom half and return IRQ_HANDLED.
> handle the timestamp locally in the sensor data and restore
> the usage of the local interrupt thread.
> - I think it works now.
> ChangeLog v1->v2:
> - v1 was missing timestamps since nothing ever stamped them.
> Restore the timestamps by simply using
> iio_trigger_generic_data_rdy_poll()
> as the top half of the threaded interrupt handler.
> ---
> drivers/iio/accel/st_accel_buffer.c | 2 +-
> drivers/iio/accel/st_accel_core.c | 1 +
> drivers/iio/common/st_sensors/st_sensors_buffer.c | 25 ++----
> drivers/iio/common/st_sensors/st_sensors_core.c | 3 +
> drivers/iio/common/st_sensors/st_sensors_trigger.c | 88 +++++++++++++++++++++-
> drivers/iio/gyro/st_gyro_buffer.c | 2 +-
> drivers/iio/gyro/st_gyro_core.c | 1 +
> drivers/iio/magnetometer/st_magn_buffer.c | 2 +-
> drivers/iio/magnetometer/st_magn_core.c | 1 +
> drivers/iio/pressure/st_pressure_buffer.c | 2 +-
> drivers/iio/pressure/st_pressure_core.c | 1 +
> include/linux/iio/common/st_sensors.h | 9 ++-
> 12 files changed, 111 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/iio/accel/st_accel_buffer.c b/drivers/iio/accel/st_accel_buffer.c
> index a1e642ee13d6..7fddc137e91e 100644
> --- a/drivers/iio/accel/st_accel_buffer.c
> +++ b/drivers/iio/accel/st_accel_buffer.c
> @@ -91,7 +91,7 @@ static const struct iio_buffer_setup_ops st_accel_buffer_setup_ops = {
>
> int st_accel_allocate_ring(struct iio_dev *indio_dev)
> {
> - return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
> + return iio_triggered_buffer_setup(indio_dev, NULL,
> &st_sensors_trigger_handler, &st_accel_buffer_setup_ops);
> }
>
> diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
> index f06f4329db5b..1d9291116556 100644
> --- a/drivers/iio/accel/st_accel_core.c
> +++ b/drivers/iio/accel/st_accel_core.c
> @@ -649,6 +649,7 @@ static const struct iio_info accel_info = {
> static const struct iio_trigger_ops st_accel_trigger_ops = {
> .owner = THIS_MODULE,
> .set_trigger_state = ST_ACCEL_TRIGGER_SET_STATE,
> + .validate_device = st_sensors_validate_device,
> };
> #define ST_ACCEL_TRIGGER_OPS (&st_accel_trigger_ops)
> #else
> diff --git a/drivers/iio/common/st_sensors/st_sensors_buffer.c b/drivers/iio/common/st_sensors/st_sensors_buffer.c
> index c55898543a47..f1693dbebb8a 100644
> --- a/drivers/iio/common/st_sensors/st_sensors_buffer.c
> +++ b/drivers/iio/common/st_sensors/st_sensors_buffer.c
> @@ -57,31 +57,20 @@ irqreturn_t st_sensors_trigger_handler(int irq, void *p)
> struct iio_poll_func *pf = p;
> struct iio_dev *indio_dev = pf->indio_dev;
> struct st_sensor_data *sdata = iio_priv(indio_dev);
> + s64 timestamp;
>
> - /* If we have a status register, check if this IRQ came from us */
> - if (sdata->sensor_settings->drdy_irq.addr_stat_drdy) {
> - u8 status;
> -
> - len = sdata->tf->read_byte(&sdata->tb, sdata->dev,
> - sdata->sensor_settings->drdy_irq.addr_stat_drdy,
> - &status);
> - if (len < 0)
> - dev_err(sdata->dev, "could not read channel status\n");
> -
> - /*
> - * If this was not caused by any channels on this sensor,
> - * return IRQ_NONE
> - */
> - if (!(status & (u8)indio_dev->active_scan_mask[0]))
> - return IRQ_NONE;
> - }
> + /* If we do timetamping here, do it before reading the values */
> + if (sdata->hw_irq_trigger)
> + timestamp = sdata->hw_timestamp;
> + else
> + timestamp = iio_get_time_ns();
>
> len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data);
> if (len < 0)
> goto st_sensors_get_buffer_element_error;
>
> iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data,
> - pf->timestamp);
> + timestamp);
>
> st_sensors_get_buffer_element_error:
> iio_trigger_notify_done(indio_dev->trig);
> diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
> index dffe00692169..928ee68fcc5f 100644
> --- a/drivers/iio/common/st_sensors/st_sensors_core.c
> +++ b/drivers/iio/common/st_sensors/st_sensors_core.c
> @@ -424,6 +424,9 @@ int st_sensors_set_dataready_irq(struct iio_dev *indio_dev, bool enable)
> else
> drdy_mask = sdata->sensor_settings->drdy_irq.mask_int2;
>
> + /* Flag to the poll function that the hardware trigger is in use */
> + sdata->hw_irq_trigger = enable;
> +
> /* Enable/Disable the interrupt generator for data ready. */
> err = st_sensors_write_data_with_mask(indio_dev,
> sdata->sensor_settings->drdy_irq.addr,
> diff --git a/drivers/iio/common/st_sensors/st_sensors_trigger.c b/drivers/iio/common/st_sensors/st_sensors_trigger.c
> index da72279fcf99..1f59bcc0f143 100644
> --- a/drivers/iio/common/st_sensors/st_sensors_trigger.c
> +++ b/drivers/iio/common/st_sensors/st_sensors_trigger.c
> @@ -17,6 +17,73 @@
> #include <linux/iio/common/st_sensors.h>
> #include "st_sensors_core.h"
>
> +/**
> + * st_sensors_irq_handler() - top half of the IRQ-based triggers
> + * @irq: irq number
> + * @p: private handler data
> + */
> +irqreturn_t st_sensors_irq_handler(int irq, void *p)
> +{
> + struct iio_trigger *trig = p;
> + struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> + struct st_sensor_data *sdata = iio_priv(indio_dev);
> +
> + /* Get the time stamp as close in time as possible */
> + sdata->hw_timestamp = iio_get_time_ns();
> + return IRQ_WAKE_THREAD;
> +}
> +
> +/**
> + * st_sensors_irq_thread() - bottom half of the IRQ-based triggers
> + * @irq: irq number
> + * @p: private handler data
> + */
> +irqreturn_t st_sensors_irq_thread(int irq, void *p)
> +{
> + struct iio_trigger *trig = p;
> + struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> + struct st_sensor_data *sdata = iio_priv(indio_dev);
> + int ret;
> +
> + /*
> + * If this trigger is backed by a hardware interrupt and we have a
> + * status register, check if this IRQ came from us
> + */
> + if (sdata->sensor_settings->drdy_irq.addr_stat_drdy) {
> + u8 status;
> +
> + ret = sdata->tf->read_byte(&sdata->tb, sdata->dev,
> + sdata->sensor_settings->drdy_irq.addr_stat_drdy,
> + &status);
> + if (ret < 0) {
> + dev_err(sdata->dev, "could not read channel status\n");
> + goto out_poll;
> + }
> + /*
> + * the lower bits of .active_scan_mask[0] is directly mapped
> + * to the channels on the sensor: either bit 0 for
> + * one-dimensional sensors, or e.g. x,y,z for accelerometers,
> + * gyroscopes or magnetometers. No sensor use more than 3
> + * channels, so cut the other status bits here.
> + */
> + status &= 0x07;
> +
> + /*
> + * If this was not caused by any channels on this sensor,
> + * return IRQ_NONE
> + */
> + if (!indio_dev->active_scan_mask)
> + return IRQ_NONE;
> + if (!(status & (u8)indio_dev->active_scan_mask[0]))
> + return IRQ_NONE;
> + }
> +
> +out_poll:
> + /* It's our IRQ: proceed to handle the register polling */
> + iio_trigger_poll_chained(p);
> + return IRQ_HANDLED;
> +}
> +
> int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
> const struct iio_trigger_ops *trigger_ops)
> {
> @@ -77,9 +144,12 @@ int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
> sdata->sensor_settings->drdy_irq.addr_stat_drdy)
> irq_trig |= IRQF_SHARED;
>
> - err = request_threaded_irq(irq,
> - iio_trigger_generic_data_rdy_poll,
> - NULL,
> + /* Let's create an interrupt thread masking the hard IRQ here */
> + irq_trig |= IRQF_ONESHOT;
> +
> + err = request_threaded_irq(sdata->get_irq_data_ready(indio_dev),
> + st_sensors_irq_handler,
> + st_sensors_irq_thread,
> irq_trig,
> sdata->trig->name,
> sdata->trig);
> @@ -119,6 +189,18 @@ void st_sensors_deallocate_trigger(struct iio_dev *indio_dev)
> }
> EXPORT_SYMBOL(st_sensors_deallocate_trigger);
>
> +int st_sensors_validate_device(struct iio_trigger *trig,
> + struct iio_dev *indio_dev)
> +{
> + struct iio_dev *indio = iio_trigger_get_drvdata(trig);
> +
> + if (indio != indio_dev)
> + return -EINVAL;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(st_sensors_validate_device);
> +
> MODULE_AUTHOR("Denis Ciocca <denis.ciocca@xxxxxx>");
> MODULE_DESCRIPTION("STMicroelectronics ST-sensors trigger");
> MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iio/gyro/st_gyro_buffer.c b/drivers/iio/gyro/st_gyro_buffer.c
> index d67b17b6a7aa..a5377044e42f 100644
> --- a/drivers/iio/gyro/st_gyro_buffer.c
> +++ b/drivers/iio/gyro/st_gyro_buffer.c
> @@ -91,7 +91,7 @@ static const struct iio_buffer_setup_ops st_gyro_buffer_setup_ops = {
>
> int st_gyro_allocate_ring(struct iio_dev *indio_dev)
> {
> - return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
> + return iio_triggered_buffer_setup(indio_dev, NULL,
> &st_sensors_trigger_handler, &st_gyro_buffer_setup_ops);
> }
>
> diff --git a/drivers/iio/gyro/st_gyro_core.c b/drivers/iio/gyro/st_gyro_core.c
> index be9057e89dc3..242a3e3c88e4 100644
> --- a/drivers/iio/gyro/st_gyro_core.c
> +++ b/drivers/iio/gyro/st_gyro_core.c
> @@ -408,6 +408,7 @@ static const struct iio_info gyro_info = {
> static const struct iio_trigger_ops st_gyro_trigger_ops = {
> .owner = THIS_MODULE,
> .set_trigger_state = ST_GYRO_TRIGGER_SET_STATE,
> + .validate_device = st_sensors_validate_device,
> };
> #define ST_GYRO_TRIGGER_OPS (&st_gyro_trigger_ops)
> #else
> diff --git a/drivers/iio/magnetometer/st_magn_buffer.c b/drivers/iio/magnetometer/st_magn_buffer.c
> index ecd3bd0a9769..0a9e8fadfa9d 100644
> --- a/drivers/iio/magnetometer/st_magn_buffer.c
> +++ b/drivers/iio/magnetometer/st_magn_buffer.c
> @@ -82,7 +82,7 @@ static const struct iio_buffer_setup_ops st_magn_buffer_setup_ops = {
>
> int st_magn_allocate_ring(struct iio_dev *indio_dev)
> {
> - return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
> + return iio_triggered_buffer_setup(indio_dev, NULL,
> &st_sensors_trigger_handler, &st_magn_buffer_setup_ops);
> }
>
> diff --git a/drivers/iio/magnetometer/st_magn_core.c b/drivers/iio/magnetometer/st_magn_core.c
> index 62036d2a9956..8250fc322c56 100644
> --- a/drivers/iio/magnetometer/st_magn_core.c
> +++ b/drivers/iio/magnetometer/st_magn_core.c
> @@ -572,6 +572,7 @@ static const struct iio_info magn_info = {
> static const struct iio_trigger_ops st_magn_trigger_ops = {
> .owner = THIS_MODULE,
> .set_trigger_state = ST_MAGN_TRIGGER_SET_STATE,
> + .validate_device = st_sensors_validate_device,
> };
> #define ST_MAGN_TRIGGER_OPS (&st_magn_trigger_ops)
> #else
> diff --git a/drivers/iio/pressure/st_pressure_buffer.c b/drivers/iio/pressure/st_pressure_buffer.c
> index 2ff53f222352..99468d0a64e7 100644
> --- a/drivers/iio/pressure/st_pressure_buffer.c
> +++ b/drivers/iio/pressure/st_pressure_buffer.c
> @@ -82,7 +82,7 @@ static const struct iio_buffer_setup_ops st_press_buffer_setup_ops = {
>
> int st_press_allocate_ring(struct iio_dev *indio_dev)
> {
> - return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
> + return iio_triggered_buffer_setup(indio_dev, NULL,
> &st_sensors_trigger_handler, &st_press_buffer_setup_ops);
> }
>
> diff --git a/drivers/iio/pressure/st_pressure_core.c b/drivers/iio/pressure/st_pressure_core.c
> index 9e9b72a8f18f..b48285739246 100644
> --- a/drivers/iio/pressure/st_pressure_core.c
> +++ b/drivers/iio/pressure/st_pressure_core.c
> @@ -425,6 +425,7 @@ static const struct iio_info press_info = {
> static const struct iio_trigger_ops st_press_trigger_ops = {
> .owner = THIS_MODULE,
> .set_trigger_state = ST_PRESS_TRIGGER_SET_STATE,
> + .validate_device = st_sensors_validate_device,
> };
> #define ST_PRESS_TRIGGER_OPS (&st_press_trigger_ops)
> #else
> diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
> index d029ffac0d69..99403b19092f 100644
> --- a/include/linux/iio/common/st_sensors.h
> +++ b/include/linux/iio/common/st_sensors.h
> @@ -223,6 +223,8 @@ struct st_sensor_settings {
> * @get_irq_data_ready: Function to get the IRQ used for data ready signal.
> * @tf: Transfer function structure used by I/O operations.
> * @tb: Transfer buffers and mutex used by I/O operations.
> + * @hw_irq_trigger: if we're using the hardware interrupt on the sensor.
> + * @hw_timestamp: Latest timestamp from the interrupt handler, when in use.
> */
> struct st_sensor_data {
> struct device *dev;
> @@ -247,6 +249,9 @@ struct st_sensor_data {
>
> const struct st_sensor_transfer_function *tf;
> struct st_sensor_transfer_buffer tb;
> +
> + bool hw_irq_trigger;
> + s64 hw_timestamp;
> };
>
> #ifdef CONFIG_IIO_BUFFER
> @@ -260,7 +265,8 @@ int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
> const struct iio_trigger_ops *trigger_ops);
>
> void st_sensors_deallocate_trigger(struct iio_dev *indio_dev);
> -
> +int st_sensors_validate_device(struct iio_trigger *trig,
> + struct iio_dev *indio_dev);
> #else
> static inline int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
> const struct iio_trigger_ops *trigger_ops)
> @@ -271,6 +277,7 @@ static inline void st_sensors_deallocate_trigger(struct iio_dev *indio_dev)
> {
> return;
> }
> +#define st_sensors_validate_device NULL
> #endif
>
> int st_sensors_init_sensor(struct iio_dev *indio_dev,
>
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