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Date:   Thu, 8 Sep 2022 17:09:14 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     Yicong Yang <yangyicong@huawei.com>
Cc:     gregkh@linuxfoundation.org, alexander.shishkin@linux.intel.com,
        leo.yan@linaro.org, james.clark@arm.com, will@kernel.org,
        robin.murphy@arm.com, acme@kernel.org, peterz@infradead.org,
        corbet@lwn.net, mark.rutland@arm.com, jonathan.cameron@huawei.com,
        john.garry@huawei.com, helgaas@kernel.org,
        lorenzo.pieralisi@arm.com, suzuki.poulose@arm.com, joro@8bytes.org,
        shameerali.kolothum.thodi@huawei.com, mingo@redhat.com,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-pci@vger.kernel.org, linux-perf-users@vger.kernel.org,
        iommu@lists.linux-foundation.org, iommu@lists.linux.dev,
        linux-doc@vger.kernel.org, prime.zeng@huawei.com,
        liuqi115@huawei.com, zhangshaokun@hisilicon.com,
        linuxarm@huawei.com, yangyicong@hisilicon.com, bagasdotme@gmail.com
Subject: Re: [PATCH v12 0/5] Add driver support for HiSilicon PCIe Tune and
 Trace device
Message-ID: <20220908230914.GA246683@p14s>
References: <20220816114414.4092-1-yangyicong@huawei.com>
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On Tue, Aug 16, 2022 at 07:44:09PM +0800, Yicong Yang wrote:
> From: Yicong Yang <yangyicong@hisilicon.com>
> 
> HiSilicon PCIe tune and trace device (PTT) is a PCIe Root Complex integrated
> Endpoint (RCiEP) device, providing the capability to dynamically monitor and
> tune the PCIe traffic (tune), and trace the TLP headers (trace).
> 
> PTT tune is designed for monitoring and adjusting PCIe link parameters. We provide
> several parameters of the PCIe link. Through the driver, user can adjust the value
> of certain parameter to affect the PCIe link for the purpose of enhancing the
> performance in certian situation.
> 
> PTT trace is designed for dumping the TLP headers to the memory, which can be
> used to analyze the transactions and usage condition of the PCIe Link. Users
> can choose filters to trace headers, by either requester ID, or those downstream
> of a set of Root Ports on the same core of the PTT device. It's also supported
> to trace the headers of certain type and of certain direction.
> 
> The driver registers a PMU device for each PTT device. The trace can be used
> through `perf record` and the traced headers can be decoded by `perf report`.
> The tune can be used through the sysfs attributes of related PMU device. See
> the documentation for the detailed usage.
> 
> This patchset adds an initial driver support for the PTT device. The userspace
> perf tool support will be sent in a separate patchset.
> 
> Change since v11:
> - Drop WARN_ON() for irq_set_affinity() failure per Greg
> - Split out userspace perf support patches according to the comments
> Link: https://lore.kernel.org/lkml/20220721130116.43366-1-yangyicong@huawei.com/
> 
> Change since v10:
> - Use title case in the documentation
> - Add RB from Bagas, thanks.
> Link: https://lore.kernel.org/lkml/20220714092710.53486-1-yangyicong@hisilicon.com/
> 
> Change since v9:
> - Add sysfs ABI description documentation
> - Remove the controversial available_{root_port, requester}_filters sysfs file
> - Shorten 2 tune sysfs attributes name and add some comments
> - Move hisi_ptt_process_auxtrace_info() to Patch 6.
> - Add RB from Leo and Ack-by from Mathieu, thanks!
> Link: https://lore.kernel.org/lkml/20220606115555.41103-1-yangyicong@hisilicon.com/
> 
> Change since v8:
> - Cleanups and one minor fix from Jonathan and John, thanks
> Link: https://lore.kernel.org/lkml/20220516125223.32012-1-yangyicong@hisilicon.com/
> 
> Change since v7:
> - Configure the DMA in probe rather than in runtime. Also use devres to manage
>   PMU device as we have no order problem now
> - Refactor the config validation function per John and Leo
> - Use a spinlock hisi_ptt::pmu_lock instead of mutex to serialize the perf process
>   in pmu::start as it's in atomic context
> - Only commit the traced data when stop, per Leo and James
> - Drop the filter dynamically updating patch from this series to simply the review
>   of the driver. That patch will be send separately.
> - add a cpumask sysfs attribute and handle the cpu hotplug events, follow the
>   uncore PMU convention
> - Other cleanups and fixes, both in driver and perf tool
> Link: https://lore.kernel.org/lkml/20220407125841.3678-1-yangyicong@hisilicon.com/
> 
> Change since v6:
> - Fix W=1 errors reported by lkp test, thanks
> 
> Change since v5:
> - Squash the PMU patch into PATCH 2 suggested by John
> - refine the commit message of PATCH 1 and some comments
> Link: https://lore.kernel.org/lkml/20220308084930.5142-1-yangyicong@hisilicon.com/
> 
> Change since v4:
> Address the comments from Jonathan, John and Ma Ca, thanks.
> - Use devm* also for allocating the DMA buffers
> - Remove the IRQ handler stub in Patch 2
> - Make functions waiting for hardware state return boolean
> - Manual remove the PMU device as it should be removed first
> - Modifier the orders in probe and removal to make them matched well
> - Make available {directions,type,format} array const and non-global
> - Using the right filter list in filters show and well protect the
>   list with mutex
> - Record the trace status with a boolean @started rather than enum
> - Optimize the process of finding the PTT devices of the perf-tool
> Link: https://lore.kernel.org/linux-pci/20220221084307.33712-1-yangyicong@hisilicon.com/
> 
> Change since v3:
> Address the comments from Jonathan and John, thanks.
> - drop members in the common struct which can be get on the fly
> - reduce buffer struct and organize the buffers with array instead of list
> - reduce the DMA reset wait time to avoid long time busy loop
> - split the available_filters sysfs attribute into two files, for root port
>   and requester respectively. Update the documentation accordingly
> - make IOMMU mapping check earlier in probe to avoid race condition. Also
>   make IOMMU quirk patch prior to driver in the series
> - Cleanups and typos fixes from John and Jonathan
> Link: https://lore.kernel.org/linux-pci/20220124131118.17887-1-yangyicong@hisilicon.com/
> 
> Change since v2:
> - address the comments from Mathieu, thanks.
>   - rename the directory to ptt to match the function of the device
>   - spinoff the declarations to a separate header
>   - split the trace function to several patches
>   - some other comments.
> - make default smmu domain type of PTT device to identity
>   Drop the RMR as it's not recommended and use an iommu_def_domain_type
>   quirk to passthrough the device DMA as suggested by Robin. 
> Link: https://lore.kernel.org/linux-pci/20211116090625.53702-1-yangyicong@hisilicon.com/
> 
> Change since v1:
> - switch the user interface of trace to perf from debugfs
> - switch the user interface of tune to sysfs from debugfs
> - add perf tool support to start trace and decode the trace data
> - address the comments of documentation from Bjorn
> - add RMR[1] support of the device as trace works in RMR mode or
>   direct DMA mode. RMR support is achieved by common APIs rather
>   than the APIs implemented in [1].
> Link: https://lore.kernel.org/lkml/1618654631-42454-1-git-send-email-yangyicong@hisilicon.com/
> [1] https://lore.kernel.org/linux-acpi/20210805080724.480-1-shameerali.kolothum.thodi@huawei.com/
> 
> Yicong Yang (5):
>   iommu/arm-smmu-v3: Make default domain type of HiSilicon PTT device to
>     identity
>   hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe
>     Tune and Trace device
>   hwtracing: hisi_ptt: Add tune function support for HiSilicon PCIe Tune
>     and Trace device
>   docs: trace: Add HiSilicon PTT device driver documentation
>   MAINTAINERS: Add maintainer for HiSilicon PTT driver
> 
>  .../ABI/testing/sysfs-devices-hisi_ptt        |   61 +
>  Documentation/trace/hisi-ptt.rst              |  298 +++++
>  Documentation/trace/index.rst                 |    1 +
>  MAINTAINERS                                   |    8 +
>  drivers/Makefile                              |    1 +
>  drivers/hwtracing/Kconfig                     |    2 +
>  drivers/hwtracing/ptt/Kconfig                 |   12 +
>  drivers/hwtracing/ptt/Makefile                |    2 +
>  drivers/hwtracing/ptt/hisi_ptt.c              | 1047 +++++++++++++++++
>  drivers/hwtracing/ptt/hisi_ptt.h              |  200 ++++
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |   21 +

I fixed the month and kernel revision in sysfs-devices-hisi_ptt before applying
this set.  You can double check that everything is to your liking in the
coresight next tree[1].

Thanks,
Mathieu

[1]. https://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git/log/?h=next


>  11 files changed, 1653 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-devices-hisi_ptt
>  create mode 100644 Documentation/trace/hisi-ptt.rst
>  create mode 100644 drivers/hwtracing/ptt/Kconfig
>  create mode 100644 drivers/hwtracing/ptt/Makefile
>  create mode 100644 drivers/hwtracing/ptt/hisi_ptt.c
>  create mode 100644 drivers/hwtracing/ptt/hisi_ptt.h
> 
> -- 
> 2.24.0
>