[v7,0/4] drivers/perf: add Synopsys DesignWare PCIe PMU driver support

  Change Log
==========

change since v6:
- improve editorial things in doc (Per Jonathan)
- change config help to generic text (Per Jonathan)
- remove macro to_dwc_pcie_pmu by moving pmu as the first member to struct dwc_pcie_pmu (Per Yicong)
- add event type check in dwc_pcie_event_show() to keep consistent with other function (Per Jonathan)
- remove intended blank line (Per Yicong)
- protect against lower 32 bits of counter overflow by try again trick (Per Jonathan)
- call pci_dev_put on all the return branch to keep the refcnt balance (Per Jonathan and Yicong)
- use devm_add_action_or_reset() to automatic unwind (Per Jonathan)
- fix picking numa-aware context cpu up when offline and offline cpu (Per Jonathan)
- simplify online cpu by init pcie_pmu->on_cpu as -1 (Per Jonathan)
- add bus_register_notifier() to handle rootport hotplug (Per Yicong)
- pick up Acked-by from Bjorn for patch 2/4 (Per Bjorn)
Link: https://lore.kernel.org/lkml/20230606074938.97724-1-xueshuai@linux.alibaba.com/T/

changes since v5:
- Rewrite the commit log to follow policy in pci_ids.h (Bjorn Helgaas)
- return error code when __dwc_pcie_pmu_probe failed (Baolin Wang)
- call 'cpuhp_remove_multi_state()' when exiting the driver. (Baolin Wang)
- pick up Review-by tag from Baolin for Patch 1 and 3
Link: https://lore.kernel.org/lkml/ZGuSimj1cuQl3W5L@bhelgaas/T/#mba3fa2572dde0deddb40b5b24a31f4df41004bdf

changes since v4:

1. addressing commens from Bjorn Helgaas:
- reorder the includes by alpha
- change all macros with upper-case hex
- change ras_des type into u16
- remove unnecessary outer "()"
- minor format changes

2. Address commensts from Jonathan Cameron:
- rewrite doc and add a example to show how to use lane event

3. fix compile error reported by: kernel test robot
- remove COMPILE_TEST and add depend on PCI in kconfig
- add Reported-by: kernel test robot <lkp@intel.com>

Changes since v3:

1. addressing comments from Robin Murphy:
- add a prepare patch to define pci id in linux/pci_ids.h
- remove unnecessary 64BIT dependency
- fix DWC_PCIE_PER_EVENT_OFF/ON macro
- remove dwc_pcie_pmu struct and move all its fileds into dwc_pcie_rp_info
- remove unnecessary format field show
- use sysfs_emit() instead of all the assorted sprintf() and snprintf() calls.
- remove unnecessary spaces and remove unnecessary cast to follow event show convention
- remove pcie_pmu_event_attr_is_visible
- fix a refcout leak on error branch when walk pci device in for_each_pci_dev
- remove bdf field from dwc_pcie_rp_info and calculate it at runtime
- finish all the checks before allocating rp_info to avoid hanging wasted memory
- remove some unused fields
- warp out control register configuration from sub function to .add()
- make function return type with a proper signature
- fix lane event count enable by clear DWC_PCIE_CNT_ENABLE field first
- pass rp_info directly to the read_*_counter helpers and in start, stop and add callbacks
- move event type validtion into .event_init()
- use is_sampling_event() to be consistent with everything else of pmu drivers
- remove unnecessary dev_err message in .event_init()
- return EINVAL instead EOPNOTSUPP for not a valid event 
- finish all the checks before start modifying the event
- fix sibling event check by comparing event->pmu with sibling->pmu
- probe PMU for each rootport independently
- use .update() as .read() directly
- remove dynamically generating symbolic name of lane event
- redefine static symbolic name of lane event and leave lane filed to user
- add CPU hotplug support

2. addressing comments from Baolin:
- add a mask to avoid possible overflow

Changes since v2 addressing comments from Baolin:
- remove redundant macro definitions
- use dev_err to print error message
- change pmu_is_register to boolean
- use PLATFORM_DEVID_NONE macro
- fix module author format

Changes since v1:

1. address comments from Jonathan:
- drop marco for PMU name and VSEC version
- simplify code with PCI standard marco
- simplify code with FIELD_PREP()/FIELD_GET() to replace shift marco
- name register filed with single _ instead double
- wrap dwc_pcie_pmu_{write}_dword out and drop meaningless snaity check 
- check vendor id while matching vesc with pci_find_vsec_capability()
- remove RP_NUM_MAX and use a list to organize PMU devices for rootports
- replace DWC_PCIE_CREATE_BDF with standard PCI_DEVID
- comments on riping register together

2. address comments from Bjorn:
- rename DWC_PCIE_VSEC_ID to DWC_PCIE_VSEC_RAS_DES_ID
- rename cap_pos to ras_des
- simplify declare of device_attribute with DEVICE_ATTR_RO
- simplify code with PCI standard macro and API like pcie_get_width_cap()
- fix some code style problem and typo
- drop meaningless snaity check of container_of

3. address comments from Yicong:
- use sysfs_emit() to replace sprintf()
- simplify iteration of pci device with for_each_pci_dev
- pick preferred CPUs on a near die and add comments
- unregister PMU drivers only for failed ones
- log on behalf PMU device and give more hint
- fix some code style problem

(Thanks for all comments and they are very valuable to me)

Cover Letter
==========

This patchset adds the PCIe Performance Monitoring Unit (PMU) driver support
for T-Head Yitian 710 SoC chip. Yitian 710 is based on the Synopsys PCI Express
Core controller IP which provides statistics feature.

Shuai Xue (4):
  docs: perf: Add description for Synopsys DesignWare PCIe PMU driver
  PCI: Add Alibaba Vendor ID to linux/pci_ids.h
  drivers/perf: add DesignWare PCIe PMU driver
  MAINTAINERS: add maintainers for DesignWare PCIe PMU driver

 .../admin-guide/perf/dwc_pcie_pmu.rst         |  94 +++
 Documentation/admin-guide/perf/index.rst      |   1 +
 MAINTAINERS                                   |   7 +
 drivers/infiniband/hw/erdma/erdma_hw.h        |   2 -
 drivers/perf/Kconfig                          |   7 +
 drivers/perf/Makefile                         |   1 +
 drivers/perf/dwc_pcie_pmu.c                   | 762 ++++++++++++++++++
 include/linux/pci_ids.h                       |   2 +
 8 files changed, 874 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/admin-guide/perf/dwc_pcie_pmu.rst
 create mode 100644 drivers/perf/dwc_pcie_pmu.c