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Message-ID: <de1af807-2298-a0f9-0122-2333741ab934@arm.com>
Date: Mon, 15 Jan 2024 09:55:55 +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 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.
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