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

[Tao Zhang <quic_taozha@quicinc.com>]

On 12/19/2023 9:56 PM, Suzuki K Poulose wrote:
> On 19/12/2023 09:22, Tao Zhang wrote:
>>
>> On 12/18/2023 6:34 PM, Suzuki K Poulose wrote:
>>> 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.
>>
>> TPDM and TPDA are two independent hardware. If you want to modify 
>> them in this way, the
>>
>
> You don't have to, as long as the header files are included ?
>
> Read my response in the other patch, where it applies.

Got it. I will update in the next patch series.


Best,

Tao

>
> Suzuki
>
>> two independent drivers will be coupled to each other. At the same 
>> time, this configuration
>>
>> is manually set in the devicetree by the users, and this check cannot 
>> avoid manual setting errors.
>>
>>   Even if the configuration is wrong, it will not cause the driver to 
>> stop working, it will only cause
>>
>> the data to be lost from the TPDM.
>>
>>>
>>>>       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.
>> Does the following sample modification meet your expectation?
>> static void tpdm_disable_dsb(struct tpdm_drvdata *drvdata)
>> {
>>      u32 val;
>>
>>      if (tpdm_has_dsb_dataset(drvdata)) {
>>          /* 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);
>>      }
>> }
>>
>> static void tpdm_disable_cmb(struct tpdm_drvdata *drvdata)
>> {
>>      u32 val;
>>
>>      if (tpdm_has_cmb_dataset(drvdata)) {
>>          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)
>> {
>>      CS_UNLOCK(drvdata->base);
>>
>>      tpdm_disable_dsb(drvdata);
>>      tpdm_disable_cmb(drvdata);
>>
>
> Yes, thats exactly I was looking for.

Got it. I will update in the next patch series.


Best,

Tao

>
>>      CS_LOCK(drvdata->base);
>>
>> }
>>
>>
>> Best,
>>
>> Tao
>>
>>>
>>>
>>> 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 */
>>>
>