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From: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>
To: <agross@kernel.org>, <andersson@kernel.org>, <konrad.dybcio@linaro.org>,
        <mani@kernel.org>
CC: <quic_msarkar@quicinc.com>, <quic_kraravin@quicinc.com>,
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        Serge Semin <fancer.lancer@gmail.com>,
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Subject: [PATCH v2 3/3] PCI: qcom: Add rx margining settings for gen4
Date: Wed, 20 Mar 2024 00:14:47 -0700
Message-ID: <20240320071527.13443-4-quic_schintav@quicinc.com>
In-Reply-To: <20240320071527.13443-1-quic_schintav@quicinc.com>
References: <20240320071527.13443-1-quic_schintav@quicinc.com>
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Add rx margining settings for gen4 operation.

Signed-off-by: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>
---
 drivers/pci/controller/dwc/pcie-designware.h | 23 +++++++++++++
 drivers/pci/controller/dwc/pcie-qcom-cmn.c   | 35 ++++++++++++++++++++
 drivers/pci/controller/dwc/pcie-qcom-cmn.h   | 11 +++++-
 drivers/pci/controller/dwc/pcie-qcom-ep.c    |  4 ++-
 drivers/pci/controller/dwc/pcie-qcom.c       |  4 ++-
 5 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 064744bfe35a..ce1c5f9c406a 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -206,6 +206,29 @@
 
 #define PCIE_PL_CHK_REG_ERR_ADDR			0xB28
 
+/*
+ * GEN4 lane margining register definitions
+ */
+#define GEN4_LANE_MARGINING_1_OFF		0xb80
+#define MARGINING_MAX_VOLTAGE_OFFSET_MASK	GENMASK(29, 24)
+#define MARGINING_NUM_VOLTAGE_STEPS_MASK	GENMASK(22, 16)
+#define MARGINING_MAX_TIMING_OFFSET_MASK	GENMASK(13, 8)
+#define MARGINING_NUM_TIMING_STEPS_MASK		GENMASK(5, 0)
+#define MARGINING_MAX_VOLTAGE_OFFSET_SHIFT	24
+#define MARGINING_NUM_VOLTAGE_STEPS_SHIFT	16
+#define MARGINING_MAX_TIMING_OFFSET_SHIFT	8
+
+#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_MASK			GENMASK(20, 16)
+#define MARGINING_SAMPLE_RATE_TIMING_MASK	GENMASK(13, 8)
+#define MARGINING_SAMPLE_RATE_VOLTAGE_MASK	GENMASK(5, 0)
+#define MARGINING_MAXLANES_SHIFT		16
+#define MARGINING_SAMPLE_RATE_TIMING_SHIFT	8
 /*
  * 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-cmn.c b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
index 208a55e8e9a1..bf6b27ee8327 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-cmn.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
@@ -53,6 +53,41 @@ void qcom_pcie_cmn_set_16gt_eq_settings(struct dw_pcie *pci)
 }
 EXPORT_SYMBOL_GPL(qcom_pcie_cmn_set_16gt_eq_settings);
 
+void qcom_pcie_cmn_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_MASK;
+	reg |= (MARGINING_MAX_VOLTAGE_OFFSET_VAL <<
+		MARGINING_MAX_VOLTAGE_OFFSET_SHIFT);
+	reg &= ~MARGINING_NUM_VOLTAGE_STEPS_MASK;
+	reg |= (MARGINING_NUM_VOLTAGE_STEPS_VAL <<
+		MARGINING_NUM_VOLTAGE_STEPS_SHIFT);
+	reg &= ~MARGINING_MAX_TIMING_OFFSET_MASK;
+	reg |= (MARGINING_MAX_TIMING_OFFSET_VAL <<
+		MARGINING_MAX_TIMING_OFFSET_SHIFT);
+	reg &= ~MARGINING_NUM_TIMING_STEPS_MASK;
+	reg |= MARGINING_NUM_TIMING_STEPS_VAL;
+	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;
+	reg |= MARGINING_SAMPLE_REPORTING_METHOD;
+	reg |= MARGINING_IND_LEFT_RIGHT_TIMING;
+	reg |= MARGINING_VOLTAGE_SUPPORTED;
+	reg &= ~MARGINING_IND_UP_DOWN_VOLTAGE;
+	reg &= ~MARGINING_MAXLANES_MASK;
+	reg |= (pci->num_lanes <<
+		MARGINING_MAXLANES_SHIFT);
+	reg &= ~MARGINING_SAMPLE_RATE_TIMING_MASK;
+	reg |= (MARGINING_SAMPLE_RATE_TIMING_VAL <<
+		MARGINING_SAMPLE_RATE_TIMING_SHIFT);
+	reg |= MARGINING_SAMPLE_RATE_VOLTAGE_VAL;
+	dw_pcie_writel_dbi(pci, GEN4_LANE_MARGINING_2_OFF, reg);
+}
+EXPORT_SYMBOL_GPL(qcom_pcie_cmn_set_16gt_rx_margining_settings);
+
 int qcom_pcie_cmn_icc_get_resource(struct dw_pcie *pci, struct icc_path *icc_mem)
 {
 	if (IS_ERR(pci))
diff --git a/drivers/pci/controller/dwc/pcie-qcom-cmn.h b/drivers/pci/controller/dwc/pcie-qcom-cmn.h
index 97302e8fafa8..11d6b00372ec 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-cmn.h
+++ b/drivers/pci/controller/dwc/pcie-qcom-cmn.h
@@ -11,9 +11,18 @@
 
 #define GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA_16GT_VAL   0x5
 #define GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA_16GT_VAL  0x5
-#define GEN3_EQ_FMDC_N_EVALS_16GT_VAL          0xD
+#define GEN3_EQ_FMDC_N_EVALS_16GT_VAL		0xD
+
+/* GEN4(16GT/s) RX margining settings */
+#define MARGINING_MAX_VOLTAGE_OFFSET_VAL	0x24
+#define MARGINING_NUM_VOLTAGE_STEPS_VAL		0x78
+#define MARGINING_MAX_TIMING_OFFSET_VAL		0x32
+#define MARGINING_NUM_TIMING_STEPS_VAL		0x10
+#define MARGINING_SAMPLE_RATE_TIMING_VAL	0x3f
+#define MARGINING_SAMPLE_RATE_VOLTAGE_VAL	0x3f
 
 int qcom_pcie_cmn_icc_get_resource(struct dw_pcie *pci, struct icc_path *icc_mem);
 int qcom_pcie_cmn_icc_init(struct dw_pcie *pci, struct icc_path *icc_mem);
 void qcom_pcie_cmn_icc_update(struct dw_pcie *pci, struct icc_path *icc_mem);
 void qcom_pcie_cmn_set_16gt_eq_settings(struct dw_pcie *pci);
+void qcom_pcie_cmn_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 b6bcab21bb9f..b4d53f96eb9e 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -438,8 +438,10 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci)
 		goto err_disable_resources;
 	}
 
-	if (pcie_link_speed[pci->link_gen] == PCIE_SPEED_16_0GT)
+	if (pcie_link_speed[pci->link_gen] == PCIE_SPEED_16_0GT) {
 		qcom_pcie_cmn_set_16gt_eq_settings(pci);
+		qcom_pcie_cmn_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 b0a22a000fa3..3dfb4d165ba5 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -263,8 +263,10 @@ static int qcom_pcie_start_link(struct dw_pcie *pci)
 {
 	struct qcom_pcie *pcie = to_qcom_pcie(pci);
 
-	if (pcie_link_speed[pci->link_gen] == PCIE_SPEED_16_0GT)
+	if (pcie_link_speed[pci->link_gen] == PCIE_SPEED_16_0GT) {
 		qcom_pcie_cmn_set_16gt_eq_settings(pci);
+		qcom_pcie_cmn_set_16gt_rx_margining_settings(pci);
+	}
 
 	/* Enable Link Training state machine */
 	if (pcie->cfg->ops->ltssm_enable)
-- 
2.43.2