[PATCH v12 0/5] Add driver support for HiSilicon PCIe Tune and Trace device

[Yicong Yang]

From: Yicong Yang <yangyicong@xxxxxxxxxxxxx>

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@xxxxxxxxxx/

Change since v10:
- Use title case in the documentation
- Add RB from Bagas, thanks.
Link: https://lore.kernel.org/lkml/20220714092710.53486-1-yangyicong@xxxxxxxxxxxxx/

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@xxxxxxxxxxxxx/

Change since v8:
- Cleanups and one minor fix from Jonathan and John, thanks
Link: https://lore.kernel.org/lkml/20220516125223.32012-1-yangyicong@xxxxxxxxxxxxx/

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@xxxxxxxxxxxxx/

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@xxxxxxxxxxxxx/

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@xxxxxxxxxxxxx/

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@xxxxxxxxxxxxx/

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@xxxxxxxxxxxxx/

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@xxxxxxxxxxxxx/
[1] https://lore.kernel.org/linux-acpi/20210805080724.480-1-shameerali.kolothum.thodi@xxxxxxxxxx/

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 +
 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

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2.24.0