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Message-ID: <dc3c1f99-7bf7-fcc5-00d5-d0e5269057c6@arm.com>
Date: Mon, 15 Jan 2024 09:57:15 +0000
From: James Clark <james.clark@....com>
To: Tao Zhang <quic_taozha@...cinc.com>,
Suzuki K Poulose <suzuki.poulose@....com>
Cc: Jinlong Mao <quic_jinlmao@...cinc.com>,
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,
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>
Subject: Re: [PATCH v3 8/8] coresight-tpdm: Add msr register support for CMB
On 15/01/2024 09:55, James Clark wrote:
>
>
> On 12/01/2024 09:12, Tao Zhang wrote:
>>
>> On 12/20/2023 5:06 PM, Tao Zhang wrote:
>>>
>>> On 12/19/2023 10:09 PM, Suzuki K Poulose wrote:
>>>> On 19/12/2023 06:58, Tao Zhang wrote:
>>>>>
>>>>> On 12/18/2023 7:02 PM, Suzuki K Poulose wrote:
>>>>>> On 21/11/2023 02:24, Tao Zhang wrote:
>>>>>>> Add the nodes for CMB subunit MSR(mux select register) support.
>>>>>>> CMB MSRs(mux select registers) is to separate mux,arbitration,
>>>>>>> ,interleaving,data packing control from stream filtering control.
>>>>>>>
>>>>>>> Reviewed-by: James Clark <james.clark@....com>
>>>>>>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
>>>>>>> Signed-off-by: Mao Jinlong <quic_jinlmao@...cinc.com>
>>>>>>> ---
>>>>>>> .../testing/sysfs-bus-coresight-devices-tpdm | 8 ++
>>>>>>> drivers/hwtracing/coresight/coresight-tpdm.c | 86
>>>>>>> +++++++++++++++++++
>>>>>>> drivers/hwtracing/coresight/coresight-tpdm.h | 16 +++-
>>>>>>> 3 files changed, 109 insertions(+), 1 deletion(-)
>>>>>>>
>>>>>>> diff --git
>>>>>>> a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>>>>> b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>>>>> index e0b77107be13..914f3fd81525 100644
>>>>>>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>>>>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>>>>> @@ -249,3 +249,11 @@ Description:
>>>>>>> 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.
>>>>>>> +
>>>>>>> +What: /sys/bus/coresight/devices/<tpdm-name>/cmb_msr/msr[0:31]
>>>>>>> +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 MSR(mux select register) for the CMB
>>>>>>> subunit
>>>>>>> + TPDM.
>>>>>>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c
>>>>>>> b/drivers/hwtracing/coresight/coresight-tpdm.c
>>>>>>> index f6cda5616e84..7e331ea436cc 100644
>>>>>>> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
>>>>>>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
>>>>>>> @@ -86,6 +86,11 @@ static ssize_t tpdm_simple_dataset_show(struct
>>>>>>> device *dev,
>>>>>>> return -EINVAL;
>>>>>>> return sysfs_emit(buf, "0x%x\n",
>>>>>>> drvdata->cmb->patt_mask[tpdm_attr->idx]);
>>>>>>> + case CMB_MSR:
>>>>>>> + if (tpdm_attr->idx >= drvdata->cmb_msr_num)
>>>>>>> + return -EINVAL;
>>>>>>> + return sysfs_emit(buf, "0x%x\n",
>>>>>>> + drvdata->cmb->msr[tpdm_attr->idx]);
>>>>>>> }
>>>>>>> return -EINVAL;
>>>>>>> }
>>>>>>> @@ -162,6 +167,12 @@ static ssize_t
>>>>>>> tpdm_simple_dataset_store(struct device *dev,
>>>>>>> else
>>>>>>> ret = -EINVAL;
>>>>>>> break;
>>>>>>> + case CMB_MSR:
>>>>>>> + if (tpdm_attr->idx < drvdata->cmb_msr_num)
>>>>>>> + drvdata->cmb->msr[tpdm_attr->idx] = val;
>>>>>>> + else
>>>>>>> + ret = -EINVAL;
>>>>>>
>>>>>>
>>>>>> minor nit: Could we not break from here instead of adding return
>>>>>> -EINVAL
>>>>>> for each case ? (I understand it has been done for the existing cases.
>>>>>> But I think we should clean up all of that, including the ones you
>>>>>> added
>>>>>> in Patch 5. Similarly for the dataset_show()
>>>>>
>>>>> Sure, do I also need to change the DSB corresponding code? If so,
>>>>> how about
>>>>>
>>>>> if I add a new patch to the next patch series to change the previous
>>>>> existing cases?
>>>>
>>>> You could fix the existing cases as a preparatory patch of the next
>>>> version of this series. I can pick it up and push it to next as I see
>>>> fit.
>>>
>>> Got it. I will update this to the next patch series.
>>
>> Hi Suzuki,
>>
>>
>> Since the dataset data is configured with spin lock protection, it needs
>> to be unlock before return.
>>
>> List my modification below. Would you mind help review to see if it is
>> good for you.
>>
>> static ssize_t tpdm_simple_dataset_store(struct device *dev,
>> struct device_attribute *attr,
>> const char *buf,
>> size_t size)
>> {
>> unsigned long val;
>>
>> struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>> struct tpdm_dataset_attribute *tpdm_attr =
>> container_of(attr, struct tpdm_dataset_attribute, attr);
>>
>> if (kstrtoul(buf, 0, &val))
>> return -EINVAL;
>>
>> spin_lock(&drvdata->spinlock);
>> switch (tpdm_attr->mem) {
>> case DSB_TRIG_PATT:
>> if (tpdm_attr->idx < TPDM_DSB_MAX_PATT)
>> drvdata->dsb->trig_patt[tpdm_attr->idx] = val;
>> else {
>> spin_unlock(&drvdata->spinlock);
>> return -EINVAL;
>> }
>> case DSB_TRIG_PATT_MASK:
>> if (tpdm_attr->idx < TPDM_DSB_MAX_PATT)
>> drvdata->dsb->trig_patt_mask[tpdm_attr->idx] = val;
>> else{
>> spin_unlock(&drvdata->spinlock);
>> return -EINVAL;
>> }
>> case DSB_PATT:
>> if (tpdm_attr->idx < TPDM_DSB_MAX_PATT)
>> drvdata->dsb->patt_val[tpdm_attr->idx] = val;
>> else{
>> spin_unlock(&drvdata->spinlock);
>> return -EINVAL;
>> }
>> case DSB_PATT_MASK:
>> if (tpdm_attr->idx < TPDM_DSB_MAX_PATT)
>> drvdata->dsb->patt_mask[tpdm_attr->idx] = val;
>> else{
>> spin_unlock(&drvdata->spinlock);
>> return -EINVAL;
>> }
>> case DSB_MSR:
>> if (tpdm_attr->idx < drvdata->dsb_msr_num)
>> drvdata->dsb->msr[tpdm_attr->idx] = val;
>> else{
>> spin_unlock(&drvdata->spinlock);
>> return -EINVAL;
>> }
>> default:
>> spin_unlock(&drvdata->spinlock);
>> return -EINVAL;
>> }
>> return size;
>>
>>
>> Best,
>>
>> Tao
>>
>
> This looks like a good fit for the new
> guard(spinlock)(&drvdata->spinlock) thing. Then there is no need to do
> all the manual unlocking.
>
Oh I see Suzuki already suggested it, nevermind.
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