Message-ID: <cdad425c-b965-44c7-a612-1c99341e95b9@arm.com>
Date: Tue, 19 Dec 2023 13:51:58 +0000
From: Suzuki K Poulose <suzuki.poulose@....com>
To: Tao Zhang <quic_taozha@...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>,
 Rob Herring <robh+dt@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc: Jinlong Mao <quic_jinlmao@...cinc.com>, 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,
 devicetree@...r.kernel.org, Tingwei Zhang <quic_tingweiz@...cinc.com>,
 Yuanfang Zhang <quic_yuanfang@...cinc.com>,
 Trilok Soni <quic_tsoni@...cinc.com>, Song Chai <quic_songchai@...cinc.com>,
 linux-arm-msm@...r.kernel.org, andersson@...nel.org
Subject: Re: [PATCH v3 6/8] coresight-tpdm: Add timestamp control register
 support for the CMB

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@....com>
>>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
>>> Signed-off-by: Jinlong Mao <quic_jinlmao@...cinc.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@...cinc.com>, Tao 
>>> Zhang (QUIC) <quic_taozha@...cinc.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@...cinc.com>, Tao Zhang 
>>> (QUIC) <quic_taozha@...cinc.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@...cinc.com>, Tao Zhang 
>>> (QUIC) <quic_taozha@...cinc.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@...cinc.com>, Tao Zhang 
>>> (QUIC) <quic_taozha@...cinc.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.

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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