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This commit adds the PCIe Performance Monitoring Unit (PMU) driver support
for T-Head Yitian SoC chip. Yitian is based on the Synopsys PCI Express
Core controller IP which provides statistics feature. The PMU is a PCIe
configuration space register block provided by each PCIe Root Port in a
Vendor-Specific Extended Capability named RAS D.E.S (Debug, Error
injection, and Statistics).
To facilitate collection of statistics the controller provides the
following two features for each Root Port:
- one 64-bit counter for Time Based Analysis (RX/TX data throughput and
time spent in each low-power LTSSM state) and
- one 32-bit counter for Event Counting (error and non-error events for
a specified lane)
Note: There is no interrupt for counter overflow.
This driver adds PMU devices for each PCIe Root Port. And the PMU device is
named based the BDF of Root Port. For example,
30:03.0 PCI bridge: Device 1ded:8000 (rev 01)
the PMU device name for this Root Port is dwc_rootport_3018.
Example usage of counting PCIe RX TLP data payload (Units of bytes)::
$# perf stat -a -e dwc_rootport_3018/Rx_PCIe_TLP_Data_Payload/
average RX bandwidth can be calculated like this:
PCIe TX Bandwidth = Rx_PCIe_TLP_Data_Payload / Measure_Time_Window
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-and-tested-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20231208025652.87192-5-xueshuai@linux.alibaba.com
[will: Fix sparse error due to use of uninitialised 'vsec' symbol in
dwc_pcie_match_des_cap()]
Signed-off-by: Will Deacon <will@kernel.org>
(cherry-picked from af9597adc2f1e3609c67c9792a2469bb64e43ae9)
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Change-Id: I470f4dc2791168760517c77dd31a4dacd7dab591
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.