Add rx lane margining settings for 16GT/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 <quic_schintav@xxxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-designware.h | 18 ++++++++++++++
drivers/pci/controller/dwc/pcie-qcom-common.c | 24 +++++++++++++++++++
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, 49 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index ad771bb52d29..e8c48855143f 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -203,6 +203,24 @@
#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(n) FIELD_PREP(GENMASK(29, 24), n)
+#define MARGINING_NUM_VOLTAGE_STEPS(n) FIELD_PREP(GENMASK(22, 16), n)
+#define MARGINING_MAX_TIMING_OFFSET(n) FIELD_PREP(GENMASK(13, 8), n)
+#define MARGINING_NUM_TIMING_STEPS(n) FIELD_PREP(GENMASK(5, 0), n)
+
+#define GEN4_LANE_MARGINING_2_OFF 0xb84
+#define MARGINING_IND_ERROR_SAMPLER(n) FIELD_PREP(BIT(28), n)
+#define MARGINING_SAMPLE_REPORTING_METHOD(n) FIELD_PREP(BIT(27), n)
+#define MARGINING_IND_LEFT_RIGHT_TIMING(n) FIELD_PREP(BIT(26), n)
+#define MARGINING_IND_UP_DOWN_VOLTAGE(n) FIELD_PREP(BIT(25), n)
+#define MARGINING_VOLTAGE_SUPPORTED(n) FIELD_PREP(BIT(24), n)
+#define MARGINING_MAXLANES(n) FIELD_PREP(GENMASK(20, 16), n)
+#define MARGINING_SAMPLE_RATE_TIMING(n) FIELD_PREP(GENMASK(13, 8), n)
+#define MARGINING_SAMPLE_RATE_VOLTAGE(n) FIELD_PREP(GENMASK(5, 0), n)
/*
* 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 a6f3eb4c3ee6..3279314ae78c 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-common.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-common.c
@@ -46,6 +46,30 @@ void qcom_pcie_common_set_16gt_eq_settings(struct dw_pcie *pci)
}
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(0x24) |
+ MARGINING_NUM_VOLTAGE_STEPS(0x78) |
+ MARGINING_MAX_TIMING_OFFSET(0x32) |
+ 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(1) |
+ MARGINING_SAMPLE_REPORTING_METHOD(1) |
+ MARGINING_IND_LEFT_RIGHT_TIMING(1) |
+ MARGINING_VOLTAGE_SUPPORTED(1) |
+ MARGINING_IND_UP_DOWN_VOLTAGE(0) |
+ MARGINING_MAXLANES(pci->num_lanes) |
+ MARGINING_SAMPLE_RATE_TIMING(0x3f) |
+ 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);
+
int qcom_pcie_common_icc_get_resource(struct dw_pcie *pci, struct icc_path **icc_mem_p)
{
*icc_mem_p = devm_of_icc_get(pci->dev, "pcie-mem");
diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.h b/drivers/pci/controller/dwc/pcie-qcom-common.h
index e72c651b0d28..b9eb78fcc766 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-common.h
+++ b/drivers/pci/controller/dwc/pcie-qcom-common.h
@@ -11,3 +11,4 @@ int qcom_pcie_common_icc_get_resource(struct dw_pcie *pci, struct icc_path **icc
int qcom_pcie_common_icc_init(struct dw_pcie *pci, struct icc_path *icc_mem);
void qcom_pcie_common_icc_update(struct dw_pcie *pci, struct icc_path *icc_mem);
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 cb75a874f76c..3032dd91514c 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_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 acf66f974edc..f69364ecf2de 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_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)
--
2.43.2
