[PATCH v2 2/3] PCI: qcom: Add equalization settings for gen4

Shashank Babu Chinta Venkata
2024-03-20T07:18:38Z

GEN3_RELATED_OFFSET is being used as shadow register for generation4 and
generation5 data rates based on rate select mask settings on this register.
Select relevant mask and equalization settings for generation4 operation.

Signed-off-by: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>
---
drivers/pci/controller/dwc/pcie-designware.h | 15 ++++++++
drivers/pci/controller/dwc/pcie-qcom-cmn.c | 36 ++++++++++++++++++++
drivers/pci/controller/dwc/pcie-qcom-cmn.h | 5 +++
drivers/pci/controller/dwc/pcie-qcom-ep.c | 3 ++
drivers/pci/controller/dwc/pcie-qcom.c | 3 ++
5 files changed, 62 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 26dae4837462..064744bfe35a 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -122,6 +122,21 @@
#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT 24
#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK GENMASK(25, 24)

+#define GEN3_EQ_CONTROL_OFF 0x8a8
+#define GEN3_EQ_CONTROL_OFF_FB_MODE_MASK GENMASK(3, 0)
+#define GEN3_EQ_CONTROL_OFF_PHASE23_EXIT_MODE BIT(4)
+#define GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK GENMASK(23, 8)
+#define GEN3_EQ_CONTROL_OFF_FOM_INC_INITIAL_EVAL BIT(24)
+
+#define GEN3_EQ_FB_MODE_DIR_CHANGE_OFF 0x8ac
+#define GEN3_EQ_FMDC_T_MIN_PHASE23_MASK GENMASK(4, 0)
+#define GEN3_EQ_FMDC_N_EVALS_MASK GENMASK(9, 5)
+#define GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA_MASK GENMASK(13, 10)
+#define GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA_MASK GENMASK(17, 14)
+#define GEN3_EQ_FMDC_N_EVALS_SHIFT 5
+#define GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA_SHIFT 10
+#define GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA_SHIFT 14
+
#define PCIE_PORT_MULTI_LANE_CTRL 0x8C0
#define PORT_MLTI_UPCFG_SUPPORT BIT(7)

diff --git a/drivers/pci/controller/dwc/pcie-qcom-cmn.c b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
index 64fa412ec293..208a55e8e9a1 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-cmn.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
@@ -17,6 +17,42 @@
#define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \
Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]))

+void qcom_pcie_cmn_set_16gt_eq_settings(struct dw_pcie *pci)
+{
+ u32 reg;
+
+ /*
+ * GEN3_RELATED_OFF is repurposed to be used with GEN4(16GT/s) rate
+ * as well based on RATE_SHADOW_SEL_MASK settings on this register.
+ */
+ reg = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
+ reg &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
+ reg &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
+ reg |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
+ dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, reg);
+
+ reg = dw_pcie_readl_dbi(pci, GEN3_EQ_FB_MODE_DIR_CHANGE_OFF);
+ reg &= ~GEN3_EQ_FMDC_T_MIN_PHASE23_MASK;
+ reg &= ~GEN3_EQ_FMDC_N_EVALS_MASK;
+ reg |= (GEN3_EQ_FMDC_N_EVALS_16GT_VAL <<
+ GEN3_EQ_FMDC_N_EVALS_SHIFT);
+ reg &= ~GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA_MASK;
+ reg |= (GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA_16GT_VAL <<
+ GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA_SHIFT);
+ reg &= ~GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA_MASK;
+ reg |= (GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA_16GT_VAL <<
+ GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA_SHIFT);
+ dw_pcie_writel_dbi(pci, GEN3_EQ_FB_MODE_DIR_CHANGE_OFF, reg);
+
+ reg = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
+ reg &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
+ reg &= ~GEN3_EQ_CONTROL_OFF_PHASE23_EXIT_MODE;
+ reg &= ~GEN3_EQ_CONTROL_OFF_FOM_INC_INITIAL_EVAL;
+ reg &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
+ dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, reg);
+}
+EXPORT_SYMBOL_GPL(qcom_pcie_cmn_set_16gt_eq_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 845eda23ae59..97302e8fafa8 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-cmn.h
+++ b/drivers/pci/controller/dwc/pcie-qcom-cmn.h
@@ -9,6 +9,11 @@
#include "../../pci.h"
#include "pcie-designware.h"

+#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
+
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);
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index ce6343426de8..b6bcab21bb9f 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -438,6 +438,9 @@ 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)
+ qcom_pcie_cmn_set_16gt_eq_settings(pci);
+
/*
* The physical address of the MMIO region which is exposed as the BAR
* should be written to MHI BASE registers.
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 57a08294c561..b0a22a000fa3 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -263,6 +263,9 @@ 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)
+ qcom_pcie_cmn_set_16gt_eq_settings(pci);
+
/* Enable Link Training state machine */
if (pcie->cfg->ops->ltssm_enable)
pcie->cfg->ops->ltssm_enable(pcie);
--
2.43.2