Re: [PATCH v2] perf: imx9_perf: Introduce AXI filter version to refactor the driver and better extension

Will Deacon
2024-12-09T15:45:43Z

On Mon, Nov 25, 2024 at 06:43:38PM +0800, Xu Yang wrote:
> The imx93 is the first supported DDR PMU that supports read transaction,
> write transaction and read beats events which corresponding respecitively
> to counter 2, 3 and 4.
>
> However, transaction-based AXI match has low accuracy when get total bits
> compared to beats-based. And imx93 doesn't assign AXI_ID to each master.
> So axi filter is not used widely on imx93. This could be regards as AXI
> filter version 1.
>
> To improve the AXI filter capability, imx95 supports 1 read beats and 3
> write beats event which corresponding respecitively to counter 2-5. imx95
> also detailed AXI_ID allocation so that most of the master could be count
> individually. This could be regards as AXI filter version 2.
>
> This will introduce AXI filter version to refactor the driver and support
> better extension, such as coming imx943.
>
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
>
> ---
> Changes in v2:
> - modify subject
> - add comments for AXI_FILTER version
> - type -> filter_ver
> ---
> drivers/perf/fsl_imx9_ddr_perf.c | 33 ++++++++++++++++++++++++--------
> 1 file changed, 25 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/perf/fsl_imx9_ddr_perf.c b/drivers/perf/fsl_imx9_ddr_perf.c
> index 3c856d9a4e97..e2c2c674b6d2 100644
> --- a/drivers/perf/fsl_imx9_ddr_perf.c
> +++ b/drivers/perf/fsl_imx9_ddr_perf.c
> @@ -63,8 +63,21 @@
>
> static DEFINE_IDA(ddr_ida);
>
> +/*
> + * V1 support 1 read transaction, 1 write transaction and 1 read beats
> + * event which corresponding respecitively to counter 2, 3 and 4.
> + */
> +#define DDR_PERF_AXI_FILTER_V1 0x1
> +
> +/*
> + * V2 support 1 read beats and 3 write beats events which corresponding
> + * respecitively to counter 2-5.
> + */
> +#define DDR_PERF_AXI_FILTER_V2 0x2
> +
> struct imx_ddr_devtype_data {
> const char *identifier; /* system PMU identifier for userspace */
> + unsigned int filter_ver; /* AXI filter version */
> };
>
> struct ddr_pmu {
> @@ -83,24 +96,27 @@ struct ddr_pmu {
>
> static const struct imx_ddr_devtype_data imx91_devtype_data = {
> .identifier = "imx91",
> + .filter_ver = DDR_PERF_AXI_FILTER_V1
> };

[...]

> -static inline bool is_imx93(struct ddr_pmu *pmu)
> +static inline bool axi_filter_v1(struct ddr_pmu *pmu)
> {
> - return pmu->devtype_data == &imx93_devtype_data;
> + return pmu->devtype_data->filter_ver == DDR_PERF_AXI_FILTER_V1;
> }

[...]

> @@ -624,11 +641,11 @@ static int ddr_perf_event_add(struct perf_event *event, int flags)
> hwc->idx = counter;
> hwc->state |= PERF_HES_STOPPED;
>
> - if (is_imx93(pmu))
> + if (axi_filter_v1(pmu))
> /* read trans, write trans, read beat */
> imx93_ddr_perf_monitor_config(pmu, event_id, counter, cfg1, cfg2);

Hmm, doesn't this change mean we now enable this for imx91 as well? My
reading of the commit message is that imx93 was the first chip which
supports this.

Will