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Message-ID: <4ae81e28-1791-4128-860f-eb6a83ea3742@arm.com>
Date: Sat, 30 Dec 2023 09:39:50 +0000
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User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v3 6/8] coresight-tpdm: Add timestamp control register
 support for the CMB
Content-Language: en-GB
To: Tao Zhang <quic_taozha@quicinc.com>,
 Mathieu Poirier <mathieu.poirier@linaro.org>,
 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
 Konrad Dybcio <konradybcio@gmail.com>, Mike Leach <mike.leach@linaro.org>,
 Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc: Jinlong Mao <quic_jinlmao@quicinc.com>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>, coresight@lists.linaro.org,
 linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
 devicetree@vger.kernel.org, Tingwei Zhang <quic_tingweiz@quicinc.com>,
 Yuanfang Zhang <quic_yuanfang@quicinc.com>,
 Trilok Soni <quic_tsoni@quicinc.com>, Song Chai <quic_songchai@quicinc.com>,
 linux-arm-msm@vger.kernel.org, andersson@kernel.org
References: <1700533494-19276-1-git-send-email-quic_taozha@quicinc.com>
 <1700533494-19276-7-git-send-email-quic_taozha@quicinc.com>
 <ebd7e310-d1b4-4b2e-a915-6241e04763d4@arm.com>
 <b61c3d70-7277-4fe7-ab67-8afc1062c737@quicinc.com>
 <cdad425c-b965-44c7-a612-1c99341e95b9@arm.com>
 <b7ef4e75-69c6-4251-8f9c-58682699e3f6@quicinc.com>
 <cc7b83ec-2c97-4a5d-87a9-36f1e13d8fc4@arm.com>
 <797eadf6-2708-47ad-a61f-88bb0d4fcf28@quicinc.com>
From: Suzuki K Poulose <suzuki.poulose@arm.com>
In-Reply-To: <797eadf6-2708-47ad-a61f-88bb0d4fcf28@quicinc.com>
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On 25/12/2023 01:55, Tao Zhang wrote:
> 
> On 12/20/2023 7:07 PM, Suzuki K Poulose wrote:
>> On 20/12/2023 09:51, Tao Zhang wrote:
>>>
>>> On 12/19/2023 9:51 PM, Suzuki K Poulose wrote:
>>>> On 19/12/2023 02:43, Tao Zhang wrote:
>>>>>
>>>>> On 12/18/2023 6:46 PM, Suzuki K Poulose wrote:
>>>>>> On 21/11/2023 02:24, Tao Zhang wrote:
>>>>>>> CMB_TIER register is CMB subunit timestamp insertion enable 
>>>>>>> register.
>>>>>>> Bit 0 is PATT_TSENAB bit. Set this bit to 1 to request a timestamp
>>>>>>> following a CMB interface pattern match. Bit 1 is XTRIG_TSENAB bit.
>>>>>>> Set this bit to 1 to request a timestamp following a CMB CTI 
>>>>>>> timestamp
>>>>>>> request. Bit 2 is TS_ALL bit. Set this bit to 1 to request timestamp
>>>>>>> for all packets.
>>>>>>>
>>>>>>> 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>
>>>>>>> ---
>>>>>>>   .../testing/sysfs-bus-coresight-devices-tpdm  |  35 ++++++
>>>>>>>   drivers/hwtracing/coresight/coresight-tpdm.c  | 116 
>>>>>>> +++++++++++++++++-
>>>>>>>   drivers/hwtracing/coresight/coresight-tpdm.h  |  14 +++
>>>>>>>   3 files changed, 162 insertions(+), 3 deletions(-)
>>>>>>>
>>>>>>> diff --git 
>>>>>>> a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm 
>>>>>>> b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>>>>> index 53662ce7c2d0..e0b77107be13 100644
>>>>>>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>>>>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>>>>> @@ -214,3 +214,38 @@ KernelVersion    6.7
>>>>>>>   Contact:    Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao 
>>>>>>> Zhang (QUIC) <quic_taozha@quicinc.com>
>>>>>>>   Description:
>>>>>>>           (RW) Set/Get the mask of the pattern for the CMB 
>>>>>>> subunit TPDM.
>>>>>>> +
>>>>>>> +What: /sys/bus/coresight/devices/<tpdm-name>/cmb_patt/enable_ts
>>>>>>> +Date:        September 2023
>>>>>>> +KernelVersion    6.7
>>>>>>> +Contact:    Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao 
>>>>>>> Zhang (QUIC) <quic_taozha@quicinc.com>
>>>>>>> +Description:
>>>>>>> +        (Write) Set the pattern timestamp of CMB tpdm. Read
>>>>>>> +        the pattern timestamp of CMB tpdm.
>>>>>>> +
>>>>>>> +        Accepts only one of the 2 values -  0 or 1.
>>>>>>> +        0 : Disable CMB pattern timestamp.
>>>>>>> +        1 : Enable CMB pattern timestamp.
>>>>>>> +
>>>>>>> +What: /sys/bus/coresight/devices/<tpdm-name>/cmb_trig_ts
>>>>>>> +Date:        September 2023
>>>>>>> +KernelVersion    6.7
>>>>>>> +Contact:    Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao 
>>>>>>> Zhang (QUIC) <quic_taozha@quicinc.com>
>>>>>>> +Description:
>>>>>>> +        (RW) Set/Get the trigger timestamp of the CMB for tpdm.
>>>>>>> +
>>>>>>> +        Accepts only one of the 2 values -  0 or 1.
>>>>>>> +        0 : Set the CMB trigger type to false
>>>>>>> +        1 : Set the CMB trigger type to true
>>>>>>> +
>>>>>>> +What: /sys/bus/coresight/devices/<tpdm-name>/cmb_ts_all
>>>>>>> +Date:        September 2023
>>>>>>> +KernelVersion    6.7
>>>>>>> +Contact:    Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao 
>>>>>>> Zhang (QUIC) <quic_taozha@quicinc.com>
>>>>>>> +Description:
>>>>>>> +        (RW) Read or write the status of timestamp upon all 
>>>>>>> interface.
>>>>>>> +        Only value 0 and 1  can be written to this node. Set 
>>>>>>> this node to 1 to requeset
>>>>>>> +        timestamp to all trace packet.
>>>>>>> +        Accepts only one of the 2 values -  0 or 1.
>>>>>>> +        0 : Disable the timestamp of all trace packets.
>>>>>>> +        1 : Enable the timestamp of all trace packets.
>>>>>>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c 
>>>>>>> b/drivers/hwtracing/coresight/coresight-tpdm.c
>>>>>>> index 894d4309f1c7..f6cda5616e84 100644
>>>>>>> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
>>>>>>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
>>>>>>> @@ -331,6 +331,36 @@ static void tpdm_enable_dsb(struct 
>>>>>>> tpdm_drvdata *drvdata)
>>>>>>>       writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
>>>>>>>   }
>>>>>>>   +static void set_cmb_tier(struct tpdm_drvdata *drvdata)
>>>>>>> +{
>>>>>>> +    u32 val;
>>>>>>> +
>>>>>>> +    val = readl_relaxed(drvdata->base + TPDM_CMB_TIER);
>>>>>>> +
>>>>>>> +    /* Clear all relevant fields */
>>>>>>> +    val &= ~(TPDM_CMB_TIER_PATT_TSENAB | TPDM_CMB_TIER_TS_ALL |
>>>>>>> +         TPDM_CMB_TIER_XTRIG_TSENAB);
>>>>>>> +
>>>>>>> +    /* Set pattern timestamp type and enablement */
>>>>>>> +    if (drvdata->cmb->patt_ts)
>>>>>>> +        val |= TPDM_CMB_TIER_PATT_TSENAB;
>>>>>>
>>>>>>  -- cut --
>>>>>>> +    else
>>>>>>> +        val &= ~TPDM_CMB_TIER_PATT_TSENAB;
>>>>>>
>>>>>>
>>>>>> All the else cases in this function are superfluous. Please remove 
>>>>>> all
>>>>>> of them.
>>>>> I will update this in the next patch.
>>>>>>
>>>>>>> +
>>>>>>> +    /* Set trigger timestamp */
>>>>>>> +    if (drvdata->cmb->trig_ts)
>>>>>>> +        val |= TPDM_CMB_TIER_XTRIG_TSENAB;
>>>>>>> +    else
>>>>>>> +        val &= ~TPDM_CMB_TIER_XTRIG_TSENAB;
>>>>>>> +
>>>>>>> +    /* Set all timestamp enablement*/
>>>>>>> +    if (drvdata->cmb->ts_all)
>>>>>>> +        val |= TPDM_CMB_TIER_TS_ALL;
>>>>>>> +    else
>>>>>>> +        val &= ~TPDM_CMB_TIER_TS_ALL;
>>>>>>> +    writel_relaxed(val, drvdata->base + TPDM_CMB_TIER);
>>>>>>> +}
>>>>>>> +
>>>>>>>   static void tpdm_enable_cmb(struct tpdm_drvdata *drvdata)
>>>>>>>   {
>>>>>>>       u32 val, i;
>>>>>>> @@ -347,6 +377,8 @@ static void tpdm_enable_cmb(struct 
>>>>>>> tpdm_drvdata *drvdata)
>>>>>>>                   drvdata->base + TPDM_CMB_XPMR(i));
>>>>>>>       }
>>>>>>>   +    set_cmb_tier(drvdata);
>>>>>>> +
>>>>>>>       val = readl_relaxed(drvdata->base + TPDM_CMB_CR);
>>>>>>>       /*
>>>>>>>        * Set to 0 for continuous CMB collection mode,
>>>>>>> @@ -695,9 +727,17 @@ static ssize_t enable_ts_show(struct device 
>>>>>>> *dev,
>>>>>>>                     char *buf)
>>>>>>>   {
>>>>>>>       struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>>>>>>> +    ssize_t size = 0;
>>>>>>>   -    return sysfs_emit(buf, "%u\n",
>>>>>>> -             (unsigned int)drvdata->dsb->patt_ts);
>>>>>>> +    if (tpdm_has_dsb_dataset(drvdata))
>>>>>>> +        size = sysfs_emit(buf, "%u\n",
>>>>>>> +                 (unsigned int)drvdata->dsb->patt_ts);
>>>>>>> +
>>>>>>> +    if (tpdm_has_cmb_dataset(drvdata))
>>>>>>> +        size = sysfs_emit(buf, "%u\n",
>>>>>>> +                 (unsigned int)drvdata->cmb->patt_ts);
>>>>>>
>>>>>> Why does this need to show two values ? This must only show ONE 
>>>>>> value.
>>>>>> How you deduce that might be based on the availability of the feature
>>>>>> set. Or store the TS value in the drvdata and use that instead for
>>>>>> controlling CMB/DSB.
>>>>>
>>>>> Since both of CMB/DSB need to have "enable_ts" SysFs file, can I 
>>>>> separate them
>>>>
>>>> The question really is, do we need fine grained control. i.e.,
>>>>
>>>> enable TS for DSB but not for CMB or vice versa.
>>>>
>>>> I am not an expert on the usage scenario of the same. So, if you/Qcomm
>>>> thinks the users need separate, fine grained control for timestamp
>>>> for the DSB and CMB, then yes, follow your recommendation below.
>>>> i.e., tpdm.../dsb_patt/enable_ts
>>>>
>>>>> as "enable_dsb_ts" and "enable_cmb_ts"? The path will be like below.
>>>>>
>>>>> tpdm0/dsb_patt/enable_dsb_ts
>>>>
>>>> You don't need enable_dsb_ts. It could be "enable_ts"
>>>>
>>>>>
>>>>> tpdm1/cmb_patt/enable_cmb_ts
>>>>>
>>>>> Is this design appropriate?
>>>>
>>>>
>>>> Otherwise, stick to single enable_ts : which enables the ts for both
>>>> CMB/DSB. And it only ever show one value : 0 (TS is disabled for both
>>>> CMB/DSB) 1 : TS enabled for both.
>>>
>>> We have a very special case, such as the TPDM supporting both CMB and
>>>
>>> DSB datasets. Although this case is very rare, it still exists.
>>>
>>> Can I use the data bit to instruct whether timestamp is enabled for 
>>> CMB/DSB or not? For example,
>>>
>>> size = sysfs_emit(buf, "%u\n",
>>>                  (unsigned int)(drvdata->dsb->patt_ts << 1 | 
>>> drvdata->cmb->patt_ts));
>>>
>>> Thus, this value can instruct the following situations.
>>>
>>> 0 - TS is disabled for both CMB/DSB
>>>
>>> 1 - TS is enabled for CMB
>>>
>>> 2 - TS is enabled for DSB
>>>
>>> 3 - TS is enabled for both
>>>
>>> Is this approach acceptable?
>>>
>>
>> No, please stick to separate controls for TS. Do not complicate
>> the user interface.
>>
>> i.e.,
>> tpdm0/dsb_patt/enable_ts
>> tpdm0/cmb_patt/enable_ts
> 
> We need to be able to control/show dsb and cmb timestamp enablement 
> independently.
> 
> Can we achieve this requirement if we use a sysfs file with the same name?

They are independent and in their respective directory (group) for CMB 
and DSB. What am I missing ?
e.g., if you want to enable TS for DSB, you do :

$ echo 1 > dsb_patt/enable_ts

And that only works for DSB not for CMB.

Suzuki

> 
> I'm not able to find a good way to achieve it. Do you have any 
> suggestions for this?
> 


> 
> Best,
> 
> Tao
> 
>>
>> Suzuki
>>
>>
>>>
>>> Best,
>>>
>>> Tao
>>>
>>>>
>>>> Suzuki
>>>>
>>>>
>>>>>>
>>>>
>>>>>> Also, the sysfs documentation needs update, if this is going to
>>>>>> control the CMB.
>>>>>
>>>>> Sure. I will update the SysFs documentation according to the 
>>>>> modification in the
>>>>>
>>>>> next patch series.
>>>>>
>>>>>
>>>>> Best,
>>>>>
>>>>> Tao
>>>>>
>>>>>>
>>>>>> Suzuki
>>>>>>
>>>>>>
>>>>>>> +
>>>>>>> +    return size;
>>>>>>>   }
>>>>>>>     /*
>>>>>>> @@ -715,8 +755,13 @@ static ssize_t enable_ts_store(struct device 
>>>>>>> *dev,
>>>>>>>           return -EINVAL;
>>>>>>>         spin_lock(&drvdata->spinlock);
>>>>>>> -    drvdata->dsb->patt_ts = !!val;
>>>>>>> +    if (tpdm_has_dsb_dataset(drvdata))
>>>>>>> +        drvdata->dsb->patt_ts = !!val;
>>>>>>> +
>>>>>>> +    if (tpdm_has_cmb_dataset(drvdata))
>>>>>>> +        drvdata->cmb->patt_ts = !!val;
>>>>>>>       spin_unlock(&drvdata->spinlock);
>>>>>>> +
>>>>>>>       return size;
>>>>>>>   }
>>>>>>>   static DEVICE_ATTR_RW(enable_ts);
>>>>>>> @@ -851,6 +896,68 @@ static ssize_t cmb_mode_store(struct device 
>>>>>>> *dev,
>>>>>>>   }
>>>>>>>   static DEVICE_ATTR_RW(cmb_mode);
>>>>>>>   +static ssize_t cmb_ts_all_show(struct device *dev,
>>>>>>> +                   struct device_attribute *attr,
>>>>>>> +                   char *buf)
>>>>>>> +{
>>>>>>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>>>>>>> +
>>>>>>> +    return sysfs_emit(buf, "%u\n",
>>>>>>> +              (unsigned int)drvdata->cmb->ts_all);
>>>>>>> +}
>>>>>>> +
>>>>>>> +static ssize_t cmb_ts_all_store(struct device *dev,
>>>>>>> +                struct device_attribute *attr,
>>>>>>> +                const char *buf,
>>>>>>> +                size_t size)
>>>>>>> +{
>>>>>>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>>>>>>> +    unsigned long val;
>>>>>>> +
>>>>>>> +    if ((kstrtoul(buf, 0, &val)) || (val & ~1UL))
>>>>>>> +        return -EINVAL;
>>>>>>> +
>>>>>>> +    spin_lock(&drvdata->spinlock);
>>>>>>> +    if (val)
>>>>>>> +        drvdata->cmb->ts_all = true;
>>>>>>> +    else
>>>>>>> +        drvdata->cmb->ts_all = false;
>>>>>>> +    spin_unlock(&drvdata->spinlock);
>>>>>>> +    return size;
>>>>>>> +}
>>>>>>> +static DEVICE_ATTR_RW(cmb_ts_all);
>>>>>>> +
>>>>>>> +static ssize_t cmb_trig_ts_show(struct device *dev,
>>>>>>> +                struct device_attribute *attr,
>>>>>>> +                char *buf)
>>>>>>> +{
>>>>>>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>>>>>>> +
>>>>>>> +    return sysfs_emit(buf, "%u\n",
>>>>>>> +              (unsigned int)drvdata->cmb->trig_ts);
>>>>>>> +}
>>>>>>> +
>>>>>>> +static ssize_t cmb_trig_ts_store(struct device *dev,
>>>>>>> +                 struct device_attribute *attr,
>>>>>>> +                 const char *buf,
>>>>>>> +                 size_t size)
>>>>>>> +{
>>>>>>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>>>>>>> +    unsigned long val;
>>>>>>> +
>>>>>>> +    if ((kstrtoul(buf, 0, &val)) || (val & ~1UL))
>>>>>>> +        return -EINVAL;
>>>>>>> +
>>>>>>> +    spin_lock(&drvdata->spinlock);
>>>>>>> +    if (val)
>>>>>>> +        drvdata->cmb->trig_ts = true;
>>>>>>> +    else
>>>>>>> +        drvdata->cmb->trig_ts = false;
>>>>>>> +    spin_unlock(&drvdata->spinlock);
>>>>>>> +    return size;
>>>>>>> +}
>>>>>>> +static DEVICE_ATTR_RW(cmb_trig_ts);
>>>>>>> +
>>>>>>>   static struct attribute *tpdm_dsb_edge_attrs[] = {
>>>>>>>       &dev_attr_ctrl_idx.attr,
>>>>>>>       &dev_attr_ctrl_val.attr,
>>>>>>> @@ -973,6 +1080,7 @@ static struct attribute 
>>>>>>> *tpdm_cmb_patt_attrs[] = {
>>>>>>>       CMB_PATT_ATTR(1),
>>>>>>>       CMB_PATT_MASK_ATTR(0),
>>>>>>>       CMB_PATT_MASK_ATTR(1),
>>>>>>> +    &dev_attr_enable_ts.attr,
>>>>>>>       NULL,
>>>>>>>   };
>>>>>>>   @@ -985,6 +1093,8 @@ static struct attribute *tpdm_dsb_attrs[] = {
>>>>>>>     static struct attribute *tpdm_cmb_attrs[] = {
>>>>>>>       &dev_attr_cmb_mode.attr,
>>>>>>> +    &dev_attr_cmb_ts_all.attr,
>>>>>>> +    &dev_attr_cmb_trig_ts.attr,
>>>>>>>       NULL,
>>>>>>>   };
>>>>>>>   diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h 
>>>>>>> b/drivers/hwtracing/coresight/coresight-tpdm.h
>>>>>>> index e90d008c1cb2..65b7ca6c4077 100644
>>>>>>> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
>>>>>>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
>>>>>>> @@ -11,6 +11,8 @@
>>>>>>>     /* CMB Subunit Registers */
>>>>>>>   #define TPDM_CMB_CR        (0xA00)
>>>>>>> +/*CMB subunit timestamp insertion enable register*/
>>>>>>> +#define TPDM_CMB_TIER        (0xA04)
>>>>>>>   /*CMB subunit timestamp pattern registers*/
>>>>>>>   #define TPDM_CMB_TPR(n)        (0xA08 + (n * 4))
>>>>>>>   /*CMB subunit timestamp pattern mask registers*/
>>>>>>> @@ -24,6 +26,12 @@
>>>>>>>   #define TPDM_CMB_CR_ENA        BIT(0)
>>>>>>>   /* Trace collection mode for CMB subunit */
>>>>>>>   #define TPDM_CMB_CR_MODE    BIT(1)
>>>>>>> +/* Timestamp control for pattern match */
>>>>>>> +#define TPDM_CMB_TIER_PATT_TSENAB    BIT(0)
>>>>>>> +/* CMB CTI timestamp request */
>>>>>>> +#define TPDM_CMB_TIER_XTRIG_TSENAB    BIT(1)
>>>>>>> +/* For timestamp fo all trace */
>>>>>>> +#define TPDM_CMB_TIER_TS_ALL        BIT(2)
>>>>>>>     /*Patten register number*/
>>>>>>>   #define TPDM_CMB_MAX_PATT        2
>>>>>>> @@ -217,6 +225,9 @@ struct dsb_dataset {
>>>>>>>    * @patt_mask:        Save value for pattern mask
>>>>>>>    * @trig_patt:        Save value for trigger pattern
>>>>>>>    * @trig_patt_mask:   Save value for trigger pattern mask
>>>>>>> + * @patt_ts:          Indicates if pattern match for timestamp 
>>>>>>> is enabled.
>>>>>>> + * @trig_ts:          Indicates if CTI trigger for timestamp is 
>>>>>>> enabled.
>>>>>>> + * @ts_all:           Indicates if timestamp is enabled for all 
>>>>>>> packets.
>>>>>>>    */
>>>>>>>   struct cmb_dataset {
>>>>>>>       u32            trace_mode;
>>>>>>> @@ -224,6 +235,9 @@ struct cmb_dataset {
>>>>>>>       u32            patt_mask[TPDM_CMB_MAX_PATT];
>>>>>>>       u32            trig_patt[TPDM_CMB_MAX_PATT];
>>>>>>>       u32            trig_patt_mask[TPDM_CMB_MAX_PATT];
>>>>>>> +    bool            patt_ts;
>>>>>>> +    bool            trig_ts;
>>>>>>> +    bool            ts_all;
>>>>>>>   };
>>>>>>>     /**
>>>>>>
>>>>
>>>> _______________________________________________
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>>
>> _______________________________________________
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