Re: [PATCH v3 3/8] coresight-tpdm: Add CMB dataset support

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 */