Re: [PATCH 2/3] drivers: devfreq: events: extend events by type of counted data

From: Chanwoo Choi
Date: Wed Apr 17 2019 - 04:21:51 EST


Hi Lukasz,

On 19. 4. 17. ìí 4:48, Lukasz Luba wrote:
> This patch adds posibility to choose what type of data should be counted
> by the PPMU counter. Now the type comes from DT where the event has been
> defined. When there is no 'event-data-type' the default value is used,
> which is 'read data in bytes'.
> It is needed when you want to know not only read+write data bytes but
> i.e. only write data in byte, or number of read requests, etc.
>
> Signed-off-by: Lukasz Luba <l.luba@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/devfreq/event/exynos-ppmu.c | 38 +++++++++++++++++++++++++------------
> include/linux/devfreq-event.h | 6 ++++++
> 2 files changed, 32 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/devfreq/event/exynos-ppmu.c b/drivers/devfreq/event/exynos-ppmu.c
> index c61de0b..e5f81a5 100644
> --- a/drivers/devfreq/event/exynos-ppmu.c
> +++ b/drivers/devfreq/event/exynos-ppmu.c
> @@ -140,6 +140,7 @@ static int exynos_ppmu_set_event(struct devfreq_event_dev *edev)
> int id = exynos_ppmu_find_ppmu_id(edev);
> int ret;
> u32 pmnc, cntens;
> + u32 evt_sel = edev->desc->data_type;
>
> if (id < 0)
> return id;
> @@ -154,9 +155,12 @@ static int exynos_ppmu_set_event(struct devfreq_event_dev *edev)
> if (ret < 0)
> return ret;
>
> - /* Set the event of Read/Write data count */
> - ret = regmap_write(info->regmap, PPMU_BEVTxSEL(id),
> - PPMU_RO_DATA_CNT | PPMU_WO_DATA_CNT);
> + /* Check if the data type has been defined in DT, use default if not */
> + if (evt_sel == UINT_MAX)
> + evt_sel = PPMU_RO_DATA_CNT | PPMU_WO_DATA_CNT;
> +
> + /* Set the event of Read or Write or both (RDWR) data count */
> + ret = regmap_write(info->regmap, PPMU_BEVTxSEL(id), evt_sel);
> if (ret < 0)
> return ret;
>
> @@ -357,6 +361,7 @@ static int exynos_ppmu_v2_set_event(struct devfreq_event_dev *edev)
> unsigned int pmnc, cntens;
> int id = exynos_ppmu_find_ppmu_id(edev);
> int ret;
> + u32 evt_sel = edev->desc->data_type;
>
> /* Enable all counters */
> ret = regmap_read(info->regmap, PPMU_V2_CNTENS, &cntens);
> @@ -368,24 +373,28 @@ static int exynos_ppmu_v2_set_event(struct devfreq_event_dev *edev)
> if (ret < 0)
> return ret;
>
> - /* Set the event of Read/Write data count */
> +
> + /* Set the event of proper data type counting.
> + * Check if the data type has been defined in DT,
> + * use default if not.
> + */
> switch (id) {
> case PPMU_PMNCNT0:
> case PPMU_PMNCNT1:
> case PPMU_PMNCNT2:
> - ret = regmap_write(info->regmap, PPMU_V2_CH_EVx_TYPE(id),
> - PPMU_V2_RO_DATA_CNT | PPMU_V2_WO_DATA_CNT);
> - if (ret < 0)
> - return ret;
> + if (evt_sel == UINT_MAX)
> + evt_sel = PPMU_V2_RO_DATA_CNT | PPMU_V2_WO_DATA_CNT;
> break;
> case PPMU_PMNCNT3:
> - ret = regmap_write(info->regmap, PPMU_V2_CH_EVx_TYPE(id),
> - PPMU_V2_EVT3_RW_DATA_CNT);
> - if (ret < 0)
> - return ret;
> + if (evt_sel == UINT_MAX)
> + evt_sel = PPMU_V2_EVT3_RW_DATA_CNT;
> break;
> }
>
> + ret = regmap_write(info->regmap, PPMU_V2_CH_EVx_TYPE(id), evt_sel);
> + if (ret < 0)
> + return ret;
> +
> /* Reset cycle counter/performance counter and enable PPMU */
> ret = regmap_read(info->regmap, PPMU_V2_PMNC, &pmnc);
> if (ret < 0)
> @@ -508,6 +517,7 @@ static int of_get_devfreq_events(struct device_node *np,
> struct device *dev = info->dev;
> struct device_node *events_np, *node;
> int i, j, count;
> + int ret;
>
> events_np = of_get_child_by_name(np, "events");
> if (!events_np) {
> @@ -544,6 +554,10 @@ static int of_get_devfreq_events(struct device_node *np,
> desc[j].driver_data = info;
>
> of_property_read_string(node, "event-name", &desc[j].name);
> + ret = of_property_read_u32(node, "event-data-type",
> + &desc[j].data_type);
> + if (!ret)
> + desc[i].data_type = UINT_MAX;

I think that it is not proper to use 'UINT_MAX'.
If you want to use the default value, you can initialize
the 'desc[i].data_type' according to the device type or compatible name.

For all exynos SoC except for exynos5433,
desc[i].data_type = PPMU_RO_DATA_CNT | PPMU_WO_DATA_CNT;

For exynos5433,
desc[i].data_type = PPMU_V2_EVT3_RW_DATA_CNT;

>
> j++;
> }
> diff --git a/include/linux/devfreq-event.h b/include/linux/devfreq-event.h
> index 4db00b0..cc160b1 100644
> --- a/include/linux/devfreq-event.h
> +++ b/include/linux/devfreq-event.h
> @@ -81,14 +81,20 @@ struct devfreq_event_ops {
> * struct devfreq_event_desc - the descriptor of devfreq-event device
> *
> * @name : the name of devfreq-event device.
> + * @data_type : the data type which is going to be counted in the register.
> * @driver_data : the private data for devfreq-event driver.
> * @ops : the operation to control devfreq-event device.
> *
> * Each devfreq-event device is described with a this structure.
> * This structure contains the various data for devfreq-event device.
> + * The data_type describes what is going to be counted in the register.
> + * It might choose to count e.g. read requests, write data in bytes, etc.
> + * The full supported list of types is present in specyfic header in:
> + * include/dt-bindings/pmu/.

Why did you make the path name as the 'pmu' instead of 'ppmu'?

It might have some confusion because 'pmu' has
the two meaning in linux kernel.
- PMU, Power Management Unit
- PMU, Performance Monitoring Unit

> */
> struct devfreq_event_desc {
> const char *name;
> + u32 data_type;
> void *driver_data;
>
> const struct devfreq_event_ops *ops;
>


--
Best Regards,
Chanwoo Choi
Samsung Electronics