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Message-ID: <00c30f02-de4e-6bd1-f220-00ae114ef91f@arm.com>
Date: Mon, 23 May 2022 10:11:47 +0100
From: Suzuki K Poulose <suzuki.poulose@....com>
To: Mao Jinlong <quic_jinlmao@...cinc.com>,
Mathieu Poirier <mathieu.poirier@...aro.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Konrad Dybcio <konradybcio@...il.com>,
Mike Leach <mike.leach@...aro.org>
Cc: Leo Yan <leo.yan@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
Tingwei Zhang <quic_tingweiz@...cinc.com>,
Yuanfang Zhang <quic_yuanfang@...cinc.com>,
Tao Zhang <quic_taozha@...cinc.com>,
Trilok Soni <quic_tsoni@...cinc.com>,
Hao Zhang <quic_hazha@...cinc.com>,
linux-arm-msm@...r.kernel.org,
Bjorn Andersson <bjorn.andersson@...aro.org>
Subject: Re: [PATCH v7 04/10] coresight-tpdm: Add DSB dataset support
Hi
On 09/05/2022 14:39, Mao Jinlong wrote:
> TPDM serves as data collection component for various dataset types.
> DSB(Discrete Single Bit) is one of the dataset types. DSB subunit
> can be enabled for data collection by writing 1 to the first bit of
> DSB_CR register. This change is to add enable/disable function for
> DSB dataset by writing DSB_CR register.
The patch looks good to me, except for some minor comment below.
>
> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
> Signed-off-by: Mao Jinlong <quic_jinlmao@...cinc.com>
> ---
> drivers/hwtracing/coresight/coresight-tpdm.c | 58 ++++++++++++++++++++
> drivers/hwtracing/coresight/coresight-tpdm.h | 23 ++++++++
> 2 files changed, 81 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 6a4e2a35053d..70df888ac565 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -20,7 +20,28 @@
>
> DEFINE_CORESIGHT_DEVLIST(tpdm_devs, "tpdm");
>
> +static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
> +{
> + u32 val;
> +
> + /* Set the enable bit of DSB control register to 1 */
> + val = readl_relaxed(drvdata->base + TPDM_DSB_CR);
> + val |= TPDM_DSB_CR_ENA;
> + writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
> +}
> +
> /* TPDM enable operations */
> +static void _tpdm_enable(struct tpdm_drvdata *drvdata)
> +{
> + CS_UNLOCK(drvdata->base);
> +
> + /* Check if DSB datasets is present for TPDM. */
> + if (drvdata->datasets & BIT(TPDM_DS_DSB))
> + tpdm_enable_dsb(drvdata);
> +
> + CS_LOCK(drvdata->base);
> +}
> +
> static int tpdm_enable(struct coresight_device *csdev,
> struct perf_event *event, u32 mode)
> {
> @@ -32,6 +53,7 @@ static int tpdm_enable(struct coresight_device *csdev,
> return -EBUSY;
> }
>
> + _tpdm_enable(drvdata);
> drvdata->enable = true;
> mutex_unlock(&drvdata->lock);
>
> @@ -39,7 +61,29 @@ static int tpdm_enable(struct coresight_device *csdev,
> return 0;
> }
>
> +static void tpdm_disable_dsb(struct tpdm_drvdata *drvdata)
> +{
> + u32 val;
> +
> + /* Set the enable bit of DSB control register to 0 */
> + val = readl_relaxed(drvdata->base + TPDM_DSB_CR);
> + val &= ~TPDM_DSB_CR_ENA;
> + writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
> +}
> +
> /* TPDM disable operations */
> +static void _tpdm_disable(struct tpdm_drvdata *drvdata)
> +{
> + CS_UNLOCK(drvdata->base);
> +
> + /* Check if DSB datasets is present for TPDM. */
> + if (drvdata->datasets & BIT(TPDM_DS_DSB))
> + tpdm_disable_dsb(drvdata);
> +
> + CS_LOCK(drvdata->base);
> +
nit: extra new line.
> +}
> +
> static void tpdm_disable(struct coresight_device *csdev,
> struct perf_event *event)
> {
> @@ -51,6 +95,7 @@ static void tpdm_disable(struct coresight_device *csdev,
> return;
> }
>
> + _tpdm_disable(drvdata);
> drvdata->enable = false;
> mutex_unlock(&drvdata->lock);
>
> @@ -66,6 +111,18 @@ static const struct coresight_ops tpdm_cs_ops = {
> .source_ops = &tpdm_source_ops,
> };
>
> +static void tpdm_init_default_data(struct tpdm_drvdata *drvdata)
> +{
> + int i;
> + u32 pidr;
> +
> + CS_UNLOCK(drvdata->base);
> + /* Get the datasets present on the TPDM. */
> + pidr = readl_relaxed(drvdata->base + CORESIGHT_PERIPHIDR0);
> + drvdata->datasets |= pidr & GENMASK(TPDM_DATASETS - 1, 0);
> + CS_LOCK(drvdata->base);
> +}
> +
> static int tpdm_probe(struct amba_device *adev, const struct amba_id *id)
> {
> struct device *dev = &adev->dev;
> @@ -104,6 +161,7 @@ static int tpdm_probe(struct amba_device *adev, const struct amba_id *id)
> if (IS_ERR(drvdata->csdev))
> return PTR_ERR(drvdata->csdev);
>
> + tpdm_init_default_data(drvdata);
> /* Decrease pm refcount when probe is done.*/
> pm_runtime_put(&adev->dev);
>
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
> index 94a7748a5426..f95aaad9c653 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
> @@ -6,6 +6,27 @@
> #ifndef _CORESIGHT_CORESIGHT_TPDM_H
> #define _CORESIGHT_CORESIGHT_TPDM_H
>
> +/* The max number of the datasets that TPDM supports */
> +#define TPDM_DATASETS 7
> +
> +/* DSB Subunit Registers */
> +#define TPDM_DSB_CR (0x780)
> +/* Enable bit for DSB subunit */
> +#define TPDM_DSB_CR_ENA BIT(0)
> +
> +/**
> + * This enum is for PERIPHIDR0 register of TPDM.
> + * The fields [6:0] of PERIPHIDR0 are used to determine what
> + * interfaces and subunits are present on a given TPDM.
> + *
> + * PERIPHIDR0[0] : Fix to 1 if ImplDef subunit present, else 0
> + * PERIPHIDR0[1] : Fix to 1 if DSB subunit present, else 0
> + */
> +enum tpdm_dataset {
> + TPDM_DS_IMPLDEF,
> + TPDM_DS_DSB,
> +};
Please could we name this explicitly to indicate the register field they
appear in ? e.g,
#define TPDM_PIDR0_DS_IMPDEF BIT(0)
#define TPDM_PIDR0_DS_DSB BIT(1)
Suzuki
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