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path: root/drivers/pci/controller/dwc/pcie-qcom-common.c
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2025-09-04PCI: qcom: Fix macro typo for CURSORZiyue Zhang
Correct a typo in the macro names GEN3_EQ_FMDC_MAX_PRE_CURSOR_DELTA and GEN3_EQ_FMDC_MAX_POST_CURSOR_DELTA. Signed-off-by: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com> [mani: reworded description] Signed-off-by: Manivannan Sadhasivam <mani@kernel.org> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com> Link: https://patch.msgid.link/20250904065225.1762793-3-ziyue.zhang@oss.qualcomm.com
2025-09-04PCI: qcom: Add equalization settings for 8.0 GT/s and 32.0 GT/sZiyue Zhang
Add lane equalization setting for 8.0 GT/s and 32.0 GT/s to enhance link stability and avoid AER Correctable Errors reported on some platforms (eg. SA8775P). 8.0 GT/s, 16.0 GT/s and 32.0 GT/s require the same equalization setting. This setting is programmed into a group of shadow registers, which can be switched to configure equalization for different speeds by writing 00b, 01b and 10b to `RATE_SHADOW_SEL`. Hence, program equalization registers in a loop using link speed as index, so that equalization setting can be programmed for 8.0 GT/s, 16.0 GT/s and 32.0 GT/s. Fixes: 489f14be0e0a ("arm64: dts: qcom: sa8775p: Add pcie0 and pcie1 nodes") Co-developed-by: Qiang Yu <qiang.yu@oss.qualcomm.com> Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com> Signed-off-by: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com> [mani: wrapped the warning to fit 100 columns, used post-increment for loop] Signed-off-by: Manivannan Sadhasivam <mani@kernel.org> Link: https://patch.msgid.link/20250904065225.1762793-2-ziyue.zhang@oss.qualcomm.com
2024-09-13PCI: qcom: Add RX lane margining settings for 16.0 GT/sShashank Babu Chinta Venkata
Add RX lane margining settings for 16.0 GT/s (GEN 4) data rate. These settings improve link stability while operating at high date rates and helps to improve signal quality. Link: https://lore.kernel.org/linux-pci/20240911-pci-qcom-gen4-stability-v7-4-743f5c1fd027@linaro.org Tested-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com> [mani: dropped the code refactoring and minor changes] Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> [kwilczynski: commit log] Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org> Reviewed-by: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2024-09-13PCI: qcom: Add equalization settings for 16.0 GT/sShashank Babu Chinta Venkata
During high data transmission rates such as 16.0 GT/s, there is an increased risk of signal loss due to poor channel quality and interference. This can impact receiver's ability to capture signals accurately. Hence, as signal compensation is achieved through appropriate lane equalization, apply lane equalization settings at both transmitter and receiver which results in an increase in the PCIe signal strength. While at it, modify the pcie-tegra194 driver to make use of the common GEN3_EQ_CONTROL_OFF definitions in pcie-designware.h. Link: https://lore.kernel.org/linux-pci/20240911-pci-qcom-gen4-stability-v7-3-743f5c1fd027@linaro.org Tested-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com> [mani: dropped the code refactoring and minor changes] Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> [kwilczynski: commit log] Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org> Reviewed-by: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>