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@xxxxxxxxxxxxxxxx>
Signed-off-by: Qiang Yu <qiang.yu@xxxxxxxxxxxxxxxx>
Signed-off-by: Ziyue Zhang <ziyue.zhang@xxxxxxxxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-designware.h | 1 -
drivers/pci/controller/dwc/pcie-qcom-common.c | 58 +++++++++++--------
drivers/pci/controller/dwc/pcie-qcom-common.h | 2 +-
drivers/pci/controller/dwc/pcie-qcom-ep.c | 6 +-
drivers/pci/controller/dwc/pcie-qcom.c | 6 +-
5 files changed, 41 insertions(+), 32 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index b5e7e18138a6..11de844428e5 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -123,7 +123,6 @@
#define GEN3_RELATED_OFF_GEN3_EQ_DISABLE BIT(16)
#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT 24
#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK GENMASK(25, 24)
-#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_16_0GT 0x1
#define GEN3_EQ_CONTROL_OFF 0x8A8
#define GEN3_EQ_CONTROL_OFF_FB_MODE GENMASK(3, 0)
diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.c b/drivers/pci/controller/dwc/pcie-qcom-common.c
index 3aad19b56da8..969c34f738a9 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-common.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-common.c
@@ -8,9 +8,11 @@
#include "pcie-designware.h"
#include "pcie-qcom-common.h"
-void qcom_pcie_common_set_16gt_equalization(struct dw_pcie *pci)
+void qcom_pcie_common_set_equalization(struct dw_pcie *pci)
{
+ struct device *dev = pci->dev;
u32 reg;
+ u16 speed;
/*
* GEN3_RELATED_OFF register is repurposed to apply equalization
@@ -19,32 +21,40 @@ void qcom_pcie_common_set_16gt_equalization(struct dw_pcie *pci)
* determines the data rate for which these equalization settings are
* applied.
*/
- 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 |= FIELD_PREP(GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK,
- GEN3_RELATED_OFF_RATE_SHADOW_SEL_16_0GT);
- 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 |
- GEN3_EQ_FMDC_N_EVALS |
- GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA |
- GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA);
- reg |= FIELD_PREP(GEN3_EQ_FMDC_T_MIN_PHASE23, 0x1) |
- FIELD_PREP(GEN3_EQ_FMDC_N_EVALS, 0xd) |
- FIELD_PREP(GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA, 0x5) |
- FIELD_PREP(GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA, 0x5);
- dw_pcie_writel_dbi(pci, GEN3_EQ_FB_MODE_DIR_CHANGE_OFF, reg);
+ for (speed = PCIE_SPEED_8_0GT; speed <= pcie_link_speed[pci->max_link_speed]; ++speed) {
+ if (speed > PCIE_SPEED_32_0GT) {
+ dev_warn(dev, "Skipped equalization settings for speeds higher than 32.0 GT/s\n");
+ break;
+ }
- reg = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
- reg &= ~(GEN3_EQ_CONTROL_OFF_FB_MODE |
- GEN3_EQ_CONTROL_OFF_PHASE23_EXIT_MODE |
- GEN3_EQ_CONTROL_OFF_FOM_INC_INITIAL_EVAL |
- GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC);
- dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, reg);
+ 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 |= FIELD_PREP(GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK,
+ speed - PCIE_SPEED_8_0GT);
+ 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 |
+ GEN3_EQ_FMDC_N_EVALS |
+ GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA |
+ GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA);
+ reg |= FIELD_PREP(GEN3_EQ_FMDC_T_MIN_PHASE23, 0x1) |
+ FIELD_PREP(GEN3_EQ_FMDC_N_EVALS, 0xd) |
+ FIELD_PREP(GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA, 0x5) |
+ FIELD_PREP(GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA, 0x5);
+ 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 |
+ GEN3_EQ_CONTROL_OFF_PHASE23_EXIT_MODE |
+ GEN3_EQ_CONTROL_OFF_FOM_INC_INITIAL_EVAL |
+ GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC);
+ dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, reg);
+ }
}
-EXPORT_SYMBOL_GPL(qcom_pcie_common_set_16gt_equalization);
+EXPORT_SYMBOL_GPL(qcom_pcie_common_set_equalization);
void qcom_pcie_common_set_16gt_lane_margining(struct dw_pcie *pci)
{
diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.h b/drivers/pci/controller/dwc/pcie-qcom-common.h
index 7d88d29e4766..7f5ca2fd9a72 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-common.h
+++ b/drivers/pci/controller/dwc/pcie-qcom-common.h
@@ -8,7 +8,7 @@
struct dw_pcie;
-void qcom_pcie_common_set_16gt_equalization(struct dw_pcie *pci);
+void qcom_pcie_common_set_equalization(struct dw_pcie *pci);
void qcom_pcie_common_set_16gt_lane_margining(struct dw_pcie *pci);
#endif
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index 60afb4d0134c..aeb166f68d55 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -511,10 +511,10 @@ 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) {
- qcom_pcie_common_set_16gt_equalization(pci);
+ qcom_pcie_common_set_equalization(pci);
+
+ if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT)
qcom_pcie_common_set_16gt_lane_margining(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 294babe1816e..31841ab9498b 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -322,10 +322,10 @@ 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) {
- qcom_pcie_common_set_16gt_equalization(pci);
+ qcom_pcie_common_set_equalization(pci);
+
+ if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT)
qcom_pcie_common_set_16gt_lane_margining(pci);
- }
/* Enable Link Training state machine */
if (pcie->cfg->ops->ltssm_enable)
--
2.43.0
