Re: [PATCH v2 0/4] PCI: dwc: Add support for configuring lane equalization presets

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

Please ignore this series it has wrong patches I will send new series to 
fix this.

- Krishna Chaitanya.

On 12/12/2024 4:02 PM, Krishna Chaitanya Chundru wrote:
> PCIe equalization presets are predefined settings used to optimize
> signal integrity by compensating for signal loss and distortion in
> high-speed data transmission.
>
> As per PCIe spec 6.0.1 revision section 8.3.3.3 & 4.2.4 for data rates
> of 8.0 GT/s, 16.0 GT/s, 32.0 GT/s, and 64.0 GT/s, there is a way to
> configure lane equalization presets for each lane to enhance the PCIe
> link reliability. Each preset value represents a different combination
> of pre-shoot and de-emphasis values. For each data rate, different
> registers are defined: for 8.0 GT/s, registers are defined in section
> 7.7.3.4; for 16.0 GT/s, in section 7.7.5.9, etc. The 8.0 GT/s rate has
> an extra receiver preset hint, requiring 16 bits per lane, while the
> remaining data rates use 8 bits per lane.
>
> Based on the number of lanes and the supported data rate, read the
> device tree property and stores in the presets structure.
>
> Based upon the lane width and supported data rate update lane
> equalization registers.
>
> This patch depends on the this dt binding pull request: https://github.com/devicetree-org/dt-schema/pull/146
>
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
> ---
> Changes in v2:
>      - Fix the kernel test robot error
>      - As suggested by konrad use for loop and read "eq-presets-%ugts", (8 << i)
>      - Link to v1: https://lore.kernel.org/r/20241116-presets-v1-0-878a837a4fee@quicinc.com
>
> ---
> Krishna chaitanya chundru (4):
>        arm64: dts: qcom: x1e80100: Add PCIe lane equalization preset properties
>        PCI: of: Add API to retrieve equalization presets from device tree
>        PCI: dwc: Improve handling of PCIe lane configuration
>        PCI: dwc: Add support for new pci function op
>
>   arch/arm64/boot/dts/qcom/x1e80100.dtsi            |  8 ++++
>   drivers/pci/controller/dwc/pcie-designware-host.c | 21 +++++++++++
>   drivers/pci/controller/dwc/pcie-designware.c      | 14 ++++++-
>   drivers/pci/controller/dwc/pcie-designware.h      |  1 +
>   drivers/pci/of.c                                  | 45 +++++++++++++++++++++++
>   drivers/pci/pci.h                                 | 17 ++++++++-
>   6 files changed, 103 insertions(+), 3 deletions(-)
> ---
> base-commit: 87d6aab2389e5ce0197d8257d5f8ee965a67c4cd
> change-id: 20241212-preset_v2-549b7acda9b7
>
> Best regards,