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a=openpgp-sha256; l=5581; i=manivannan.sadhasivam@linaro.org; h=from:subject:message-id; bh=+UyPXoBEoMHThbW48iMeb9Epx8yMpHkZz7Vs41Qi22Y=; b=owEBbQGS/pANAwAKAVWfEeb+kc71AcsmYgBm2Ag/CKqFkchoOhfhcoyHVeR3YDPEC2OUGEWKm 6WLB/Ag6VaJATMEAAEKAB0WIQRnpUMqgUjL2KRYJ5dVnxHm/pHO9QUCZtgIPwAKCRBVnxHm/pHO 9T9aB/0cOOobTwlsF0wmCW6pgspvSb7L5UPaZJLD9me+c+UTbkKm+gmOC/7F0uhZc0mk91W104B 7uqxEJOqSw585He5P6MCADmUTIV52H+sBvRQKQ9gEHrUd8GdC4neN+Je/JQMJKrldwkDj59AUvV NhiLjHvqT9p/xfskS0QpnO161HeZU3Qa0GcEXwqpL9jGAz1gjzVsUbcGffGGuilzGJtbvxar9YT HktzXUuO2QX2etlTpsm6qRmZD4DdzQaVpZ68hW/oxYjiiebbya9VKk+t6nwHIvRhqIznGDKFHrY +Vh7w8QtIvvWul1i7Z58hfnF1TeZTuO++OOnhhDw9ApQUHV9 X-Developer-Key: i=manivannan.sadhasivam@linaro.org; a=openpgp; fpr=C668AEC3C3188E4C611465E7488550E901166008 X-Endpoint-Received: by B4 Relay for manivannan.sadhasivam@linaro.org/default with auth_id=185 X-Original-From: Manivannan Sadhasivam X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240904_001204_013647_9CD3C35E X-CRM114-Status: GOOD ( 14.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: manivannan.sadhasivam@linaro.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Shashank 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. Signed-off-by: Shashank Babu Chinta Venkata Reviewed-by: Manivannan Sadhasivam [mani: dropped the code refactoring and minor changes] Signed-off-by: Manivannan Sadhasivam --- drivers/pci/controller/dwc/pcie-designware.h | 18 ++++++++++++++++ drivers/pci/controller/dwc/pcie-qcom-common.c | 31 +++++++++++++++++++++++++++ drivers/pci/controller/dwc/pcie-qcom-common.h | 1 + drivers/pci/controller/dwc/pcie-qcom-ep.c | 4 +++- drivers/pci/controller/dwc/pcie-qcom.c | 4 +++- 5 files changed, 56 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index 51744ad25575..f5be99731f7e 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -209,6 +209,24 @@ #define PCIE_PL_CHK_REG_ERR_ADDR 0xB28 +/* + * 16.0 GT/s (GEN4) lane margining register definitions + */ +#define GEN4_LANE_MARGINING_1_OFF 0xb80 +#define MARGINING_MAX_VOLTAGE_OFFSET GENMASK(29, 24) +#define MARGINING_NUM_VOLTAGE_STEPS GENMASK(22, 16) +#define MARGINING_MAX_TIMING_OFFSET GENMASK(13, 8) +#define MARGINING_NUM_TIMING_STEPS GENMASK(5, 0) + +#define GEN4_LANE_MARGINING_2_OFF 0xb84 +#define MARGINING_IND_ERROR_SAMPLER BIT(28) +#define MARGINING_SAMPLE_REPORTING_METHOD BIT(27) +#define MARGINING_IND_LEFT_RIGHT_TIMING BIT(26) +#define MARGINING_IND_UP_DOWN_VOLTAGE BIT(25) +#define MARGINING_VOLTAGE_SUPPORTED BIT(24) +#define MARGINING_MAXLANES GENMASK(20, 16) +#define MARGINING_SAMPLE_RATE_TIMING GENMASK(13, 8) +#define MARGINING_SAMPLE_RATE_VOLTAGE GENMASK(5, 0) /* * iATU Unroll-specific register definitions * From 4.80 core version the address translation will be made by unroll diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.c b/drivers/pci/controller/dwc/pcie-qcom-common.c index dc7d93db9dc5..99b75e7f085d 100644 --- a/drivers/pci/controller/dwc/pcie-qcom-common.c +++ b/drivers/pci/controller/dwc/pcie-qcom-common.c @@ -43,3 +43,34 @@ void qcom_pcie_common_set_16gt_eq_settings(struct dw_pcie *pci) dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, reg); } EXPORT_SYMBOL_GPL(qcom_pcie_common_set_16gt_eq_settings); + +void qcom_pcie_common_set_16gt_rx_margining_settings(struct dw_pcie *pci) +{ + u32 reg; + + reg = dw_pcie_readl_dbi(pci, GEN4_LANE_MARGINING_1_OFF); + reg &= ~(MARGINING_MAX_VOLTAGE_OFFSET | + MARGINING_NUM_VOLTAGE_STEPS | + MARGINING_MAX_TIMING_OFFSET | + MARGINING_NUM_TIMING_STEPS); + reg |= FIELD_PREP(MARGINING_MAX_VOLTAGE_OFFSET, 0x24) | + FIELD_PREP(MARGINING_NUM_VOLTAGE_STEPS, 0x78) | + FIELD_PREP(MARGINING_MAX_TIMING_OFFSET, 0x32) | + FIELD_PREP(MARGINING_NUM_TIMING_STEPS, 0x10); + dw_pcie_writel_dbi(pci, GEN4_LANE_MARGINING_1_OFF, reg); + + reg = dw_pcie_readl_dbi(pci, GEN4_LANE_MARGINING_2_OFF); + reg |= MARGINING_IND_ERROR_SAMPLER | + MARGINING_SAMPLE_REPORTING_METHOD | + MARGINING_IND_LEFT_RIGHT_TIMING | + MARGINING_VOLTAGE_SUPPORTED; + reg &= ~(MARGINING_IND_UP_DOWN_VOLTAGE | + MARGINING_MAXLANES | + MARGINING_SAMPLE_RATE_TIMING | + MARGINING_SAMPLE_RATE_VOLTAGE); + reg |= FIELD_PREP(MARGINING_MAXLANES, pci->num_lanes) | + FIELD_PREP(MARGINING_SAMPLE_RATE_TIMING, 0x3f) | + FIELD_PREP(MARGINING_SAMPLE_RATE_VOLTAGE, 0x3f); + dw_pcie_writel_dbi(pci, GEN4_LANE_MARGINING_2_OFF, reg); +} +EXPORT_SYMBOL_GPL(qcom_pcie_common_set_16gt_rx_margining_settings); diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.h b/drivers/pci/controller/dwc/pcie-qcom-common.h index 259e04b7bdf9..e9ddc901082e 100644 --- a/drivers/pci/controller/dwc/pcie-qcom-common.h +++ b/drivers/pci/controller/dwc/pcie-qcom-common.h @@ -6,3 +6,4 @@ #include "pcie-designware.h" void qcom_pcie_common_set_16gt_eq_settings(struct dw_pcie *pci); +void qcom_pcie_common_set_16gt_rx_margining_settings(struct dw_pcie *pci); diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c index af83470216e8..5c220f2ecafe 100644 --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c @@ -487,8 +487,10 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci) goto err_disable_resources; } - if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT) + if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT) { qcom_pcie_common_set_16gt_eq_settings(pci); + qcom_pcie_common_set_16gt_rx_margining_settings(pci); + } /* * The physical address of the MMIO region which is exposed as the BAR diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index 2742e82fdcb3..b0b1d8d34279 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -284,8 +284,10 @@ static int qcom_pcie_start_link(struct dw_pcie *pci) { struct qcom_pcie *pcie = to_qcom_pcie(pci); - if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT) + if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT) { qcom_pcie_common_set_16gt_eq_settings(pci); + qcom_pcie_common_set_16gt_rx_margining_settings(pci); + } /* Enable Link Training state machine */ if (pcie->cfg->ops->ltssm_enable)