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SubjectRe: [PATCH v3 3/8] coresight-tpdm: Add CMB dataset support
From
On 21/11/2023 02:24, Tao Zhang wrote:
> CMB (continuous multi-bit) is one of TPDM's dataset type. CMB subunit
> can be enabled for data collection by writing 1 to the first bit of
> CMB_CR register. This change is to add enable/disable function for
> CMB dataset by writing CMB_CR register.
>
> Reviewed-by: James Clark <james.clark@arm.com>
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> Signed-off-by: Jinlong Mao <quic_jinlmao@quicinc.com>
> ---
> drivers/hwtracing/coresight/coresight-tpdm.c | 31 ++++++++++++++++++++
> drivers/hwtracing/coresight/coresight-tpdm.h | 8 +++++
> 2 files changed, 39 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 97654aa4b772..c8bb38822e08 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -131,6 +131,11 @@ static bool tpdm_has_dsb_dataset(struct tpdm_drvdata *drvdata)
> return (drvdata->datasets & TPDM_PIDR0_DS_DSB);
> }
>
> +static bool tpdm_has_cmb_dataset(struct tpdm_drvdata *drvdata)
> +{
> + return (drvdata->datasets & TPDM_PIDR0_DS_CMB);
> +}
> +
> static umode_t tpdm_dsb_is_visible(struct kobject *kobj,
> struct attribute *attr, int n)
> {
> @@ -267,6 +272,17 @@ static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
> writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
> }
>
> +static void tpdm_enable_cmb(struct tpdm_drvdata *drvdata)
> +{
> + u32 val;
> +
> + val = readl_relaxed(drvdata->base + TPDM_CMB_CR);
> + val |= TPDM_CMB_CR_ENA;
> +
> + /* Set the enable bit of CMB control register to 1 */
> + writel_relaxed(val, drvdata->base + TPDM_CMB_CR);
> +}
> +
> /*
> * TPDM enable operations
> * The TPDM or Monitor serves as data collection component for various
> @@ -281,6 +297,8 @@ static void __tpdm_enable(struct tpdm_drvdata *drvdata)
>
> if (tpdm_has_dsb_dataset(drvdata))
> tpdm_enable_dsb(drvdata);
> + if (tpdm_has_cmb_dataset(drvdata))
> + tpdm_enable_cmb(drvdata);
>

Don't we need to add this check in the "property read" section ?
Otherwise, we could generate warnings unnecessarily ?

i.e, if (tpdm_has_cmb_..())
rc |= fwnode_..read_property(cmb-elem-size...)

Similarly for DSB.

> CS_LOCK(drvdata->base);
> }
> @@ -314,6 +332,17 @@ static void tpdm_disable_dsb(struct tpdm_drvdata *drvdata)
> writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
> }
>
> +static void tpdm_disable_cmb(struct tpdm_drvdata *drvdata)
> +{
> + u32 val;
> +
> + val = readl_relaxed(drvdata->base + TPDM_CMB_CR);
> + val &= ~TPDM_CMB_CR_ENA;
> +
> + /* Set the enable bit of CMB control register to 0 */
> + writel_relaxed(val, drvdata->base + TPDM_CMB_CR);
> +}
> +
> /* TPDM disable operations */
> static void __tpdm_disable(struct tpdm_drvdata *drvdata)
> {
> @@ -321,6 +350,8 @@ static void __tpdm_disable(struct tpdm_drvdata *drvdata)
>
> if (tpdm_has_dsb_dataset(drvdata))
> tpdm_disable_dsb(drvdata);
> + if (tpdm_has_cmb_dataset(drvdata))
> + tpdm_disable_cmb(drvdata);

minor nit: Instead of having these :

if (tpdm_has_XY_()
tpdm_{enable/disable}_XY_()
I prefer :

tpdm_{enable/disable}_XY_

and the helper take care of returning early if the feature is
not present.


Suzuki

>
> CS_LOCK(drvdata->base);
> }
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
> index 4115b2a17b8d..0098c58dfdd6 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
> @@ -9,6 +9,12 @@
> /* The max number of the datasets that TPDM supports */
> #define TPDM_DATASETS 7
>
> +/* CMB Subunit Registers */
> +#define TPDM_CMB_CR (0xA00)
> +
> +/* Enable bit for CMB subunit */
> +#define TPDM_CMB_CR_ENA BIT(0)
> +
> /* DSB Subunit Registers */
> #define TPDM_DSB_CR (0x780)
> #define TPDM_DSB_TIER (0x784)
> @@ -79,10 +85,12 @@
> *
> * PERIPHIDR0[0] : Fix to 1 if ImplDef subunit present, else 0
> * PERIPHIDR0[1] : Fix to 1 if DSB subunit present, else 0
> + * PERIPHIDR0[2] : Fix to 1 if CMB subunit present, else 0
> */
>
> #define TPDM_PIDR0_DS_IMPDEF BIT(0)
> #define TPDM_PIDR0_DS_DSB BIT(1)
> +#define TPDM_PIDR0_DS_CMB BIT(2)
>
> #define TPDM_DSB_MAX_LINES 256
> /* MAX number of EDCR registers */


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