* [PATCH v4 1/3] PCI: qcom: Add equalization settings for 8.0 GT/s
2025-07-14 8:21 [PATCH v4 0/3] Add Equalization Settings for 8.0 GT/s and Add PCIe Lane Equalization Preset Properties for 8.0 GT/s and 16.0 GT/s Ziyue Zhang
@ 2025-07-14 8:21 ` Ziyue Zhang
2025-07-14 8:21 ` [PATCH v4 2/3] PCI: qcom: fix macro typo for CURSOR Ziyue Zhang
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Ziyue Zhang @ 2025-07-14 8:21 UTC (permalink / raw)
To: andersson, konradybcio, robh, krzk+dt, conor+dt, jingoohan1, mani,
lpieralisi, kwilczynski, bhelgaas, johan+linaro, vkoul, kishon,
neil.armstrong, abel.vesa, kw
Cc: linux-arm-msm, devicetree, linux-kernel, linux-pci, linux-phy,
qiang.yu, quic_krichai, quic_vbadigan, Ziyue Zhang
Add lane equalization setting for 8.0 GT/s to enhance link stability and
avoid AER Correctable Errors reported on some platforms (eg. SA8775P).
8.0 GT/s and 16.0 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 to `RATE_SHADOW_SEL`.
Hence program equalization registers in a loop using link speed as index,
so that equalization setting can be programmed for both 8.0 GT/s and
16.0 GT/s.
Co-developed-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
Signed-off-by: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com>
---
drivers/pci/controller/dwc/pcie-designware.h | 1 -
drivers/pci/controller/dwc/pcie-qcom-common.c | 54 ++++++++++---------
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, 37 insertions(+), 32 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 1bf1e08ab4c3..8e0a02abab60 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..3914d409b486 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-common.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-common.c
@@ -8,9 +8,10 @@
#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)
{
u32 reg;
+ u16 speed;
/*
* GEN3_RELATED_OFF register is repurposed to apply equalization
@@ -19,32 +20,37 @@ 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_16_0GT)
+ break;
+ 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_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_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 bf7c6ac0f3e3..aaf060bf39d4 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 9b12f2f02042..e5e686705e48 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -298,10 +298,10 @@ 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)
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v4 2/3] PCI: qcom: fix macro typo for CURSOR
2025-07-14 8:21 [PATCH v4 0/3] Add Equalization Settings for 8.0 GT/s and Add PCIe Lane Equalization Preset Properties for 8.0 GT/s and 16.0 GT/s Ziyue Zhang
2025-07-14 8:21 ` [PATCH v4 1/3] PCI: qcom: Add equalization settings for 8.0 GT/s Ziyue Zhang
@ 2025-07-14 8:21 ` Ziyue Zhang
2025-07-14 8:21 ` [PATCH v4 3/3] arm64: dts: qcom: sa8775p: Add PCIe lane equalization preset properties Ziyue Zhang
2025-08-12 8:32 ` [PATCH v4 0/3] Add Equalization Settings for 8.0 GT/s and Add PCIe Lane Equalization Preset Properties for 8.0 GT/s and 16.0 GT/s Ziyue Zhang
3 siblings, 0 replies; 5+ messages in thread
From: Ziyue Zhang @ 2025-07-14 8:21 UTC (permalink / raw)
To: andersson, konradybcio, robh, krzk+dt, conor+dt, jingoohan1, mani,
lpieralisi, kwilczynski, bhelgaas, johan+linaro, vkoul, kishon,
neil.armstrong, abel.vesa, kw
Cc: linux-arm-msm, devicetree, linux-kernel, linux-pci, linux-phy,
qiang.yu, quic_krichai, quic_vbadigan, Ziyue Zhang, Konrad Dybcio
Corrected a typo in the macro name GEN3_EQ_FMDC_MAX_PRE_CURSOR_DELTA and
GEN3_EQ_FMDC_MAX_POST_CURSOR_DELTA to ensure consistency and avoid
potential issues.
Signed-off-by: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
drivers/pci/controller/dwc/pcie-designware.h | 4 ++--
drivers/pci/controller/dwc/pcie-qcom-common.c | 8 ++++----
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 8e0a02abab60..475f28512aac 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -133,8 +133,8 @@
#define GEN3_EQ_FB_MODE_DIR_CHANGE_OFF 0x8AC
#define GEN3_EQ_FMDC_T_MIN_PHASE23 GENMASK(4, 0)
#define GEN3_EQ_FMDC_N_EVALS GENMASK(9, 5)
-#define GEN3_EQ_FMDC_MAX_PRE_CUSROR_DELTA GENMASK(13, 10)
-#define GEN3_EQ_FMDC_MAX_POST_CUSROR_DELTA GENMASK(17, 14)
+#define GEN3_EQ_FMDC_MAX_PRE_CURSOR_DELTA GENMASK(13, 10)
+#define GEN3_EQ_FMDC_MAX_POST_CURSOR_DELTA GENMASK(17, 14)
#define PCIE_PORT_MULTI_LANE_CTRL 0x8C0
#define PORT_MLTI_UPCFG_SUPPORT BIT(7)
diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.c b/drivers/pci/controller/dwc/pcie-qcom-common.c
index 3914d409b486..dffe48da8f96 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-common.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-common.c
@@ -34,12 +34,12 @@ void qcom_pcie_common_set_equalization(struct dw_pcie *pci)
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);
+ GEN3_EQ_FMDC_MAX_PRE_CURSOR_DELTA |
+ GEN3_EQ_FMDC_MAX_POST_CURSOR_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);
+ FIELD_PREP(GEN3_EQ_FMDC_MAX_PRE_CURSOR_DELTA, 0x5) |
+ FIELD_PREP(GEN3_EQ_FMDC_MAX_POST_CURSOR_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);
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v4 3/3] arm64: dts: qcom: sa8775p: Add PCIe lane equalization preset properties
2025-07-14 8:21 [PATCH v4 0/3] Add Equalization Settings for 8.0 GT/s and Add PCIe Lane Equalization Preset Properties for 8.0 GT/s and 16.0 GT/s Ziyue Zhang
2025-07-14 8:21 ` [PATCH v4 1/3] PCI: qcom: Add equalization settings for 8.0 GT/s Ziyue Zhang
2025-07-14 8:21 ` [PATCH v4 2/3] PCI: qcom: fix macro typo for CURSOR Ziyue Zhang
@ 2025-07-14 8:21 ` Ziyue Zhang
2025-08-12 8:32 ` [PATCH v4 0/3] Add Equalization Settings for 8.0 GT/s and Add PCIe Lane Equalization Preset Properties for 8.0 GT/s and 16.0 GT/s Ziyue Zhang
3 siblings, 0 replies; 5+ messages in thread
From: Ziyue Zhang @ 2025-07-14 8:21 UTC (permalink / raw)
To: andersson, konradybcio, robh, krzk+dt, conor+dt, jingoohan1, mani,
lpieralisi, kwilczynski, bhelgaas, johan+linaro, vkoul, kishon,
neil.armstrong, abel.vesa, kw
Cc: linux-arm-msm, devicetree, linux-kernel, linux-pci, linux-phy,
qiang.yu, quic_krichai, quic_vbadigan, Ziyue Zhang, Konrad Dybcio
Add PCIe lane equalization preset properties with all values set to 5 for
8.0 GT/s and 16.0 GT/s data rates to enhance link stability.
Co-developed-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
Signed-off-by: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Acked-by: Manivannan Sadhasivam <mani@kernel.org>
---
arch/arm64/boot/dts/qcom/sa8775p.dtsi | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/arm64/boot/dts/qcom/sa8775p.dtsi b/arch/arm64/boot/dts/qcom/sa8775p.dtsi
index fed34717460f..61f094c51815 100644
--- a/arch/arm64/boot/dts/qcom/sa8775p.dtsi
+++ b/arch/arm64/boot/dts/qcom/sa8775p.dtsi
@@ -7642,6 +7642,9 @@ pcie0: pcie@1c00000 {
phys = <&pcie0_phy>;
phy-names = "pciephy";
+ eq-presets-8gts = /bits/ 16 <0x5555 0x5555>;
+ eq-presets-16gts = /bits/ 8 <0x55 0x55>;
+
status = "disabled";
pcieport0: pcie@0 {
@@ -7808,6 +7811,9 @@ pcie1: pcie@1c10000 {
phys = <&pcie1_phy>;
phy-names = "pciephy";
+ eq-presets-8gts = /bits/ 16 <0x5555 0x5555 0x5555 0x5555>;
+ eq-presets-16gts = /bits/ 8 <0x55 0x55 0x55 0x55>;
+
status = "disabled";
pcie@0 {
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v4 0/3] Add Equalization Settings for 8.0 GT/s and Add PCIe Lane Equalization Preset Properties for 8.0 GT/s and 16.0 GT/s
2025-07-14 8:21 [PATCH v4 0/3] Add Equalization Settings for 8.0 GT/s and Add PCIe Lane Equalization Preset Properties for 8.0 GT/s and 16.0 GT/s Ziyue Zhang
` (2 preceding siblings ...)
2025-07-14 8:21 ` [PATCH v4 3/3] arm64: dts: qcom: sa8775p: Add PCIe lane equalization preset properties Ziyue Zhang
@ 2025-08-12 8:32 ` Ziyue Zhang
3 siblings, 0 replies; 5+ messages in thread
From: Ziyue Zhang @ 2025-08-12 8:32 UTC (permalink / raw)
To: andersson, konradybcio, robh, krzk+dt, conor+dt, jingoohan1, mani,
lpieralisi, kwilczynski, bhelgaas, johan+linaro, vkoul, kishon,
neil.armstrong, abel.vesa, kw
Cc: linux-arm-msm, devicetree, linux-kernel, linux-pci, linux-phy,
qiang.yu, quic_krichai, quic_vbadigan
On 7/14/2025 4:21 PM, Ziyue Zhang wrote:
> This series adds add equalization settings for 8.0 GT/s, and add PCIe lane equalization
> preset properties for 8.0 GT/s and 16.0 GT/s for sa8775p ride platform, which fix AER
> errors.
>
> While equalization settings for 16 GT/s have already been set, this update adds the
> required equalization settings for PCIe operating at 8.0 GT/s, including the
> configuration of shadow registers, ensuring optimal performance and stability.
>
> The DT change for sa8775p add PCIe lane equalization preset properties for 8 GT/s
> and 16 GT/s data rates used in lane equalization procedure.
>
> Signed-off-by: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com>
>
> Changes in v4:
> - Bail out early if the link speed > 16 GT/s and use pci->max_link_speed directly (Mani)
> - Fix the build warning. (Bjorn)
> - Link to v3: https://lore.kernel.org/all/8ccd3731-8dbc-4972-a79a-ba78e90ec4a8@quicinc.com/
>
> Changes in v3:
> - Delte TODO tag and warn print in pcie-qcom-common.c. (Bjorn)
> - Refined the commit message for better readability. (Bjorn)
> - Link to v2: https://lore.kernel.org/all/20250611100319.464803-1-quic_ziyuzhan@quicinc.com/
>
> Changes in v2:
> - Update code in pcie-qcom-common.c make it easier to read. (Neil)
> - Fix the compile error.
> - Link to v1: https://lore.kernel.org/all/20250604091946.1890602-1-quic_ziyuzhan@quicinc.com
>
>
> Ziyue Zhang (3):
> PCI: qcom: Add equalization settings for 8.0 GT/s
> PCI: qcom: fix macro typo for CURSOR
> arm64: dts: qcom: sa8775p: Add PCIe lane equalization preset
> properties
>
> arch/arm64/boot/dts/qcom/sa8775p.dtsi | 6 +++
> drivers/pci/controller/dwc/pcie-designware.h | 5 +-
> drivers/pci/controller/dwc/pcie-qcom-common.c | 54 ++++++++++---------
> 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 +--
> 6 files changed, 45 insertions(+), 34 deletions(-)
>
>
> base-commit: 58ba80c4740212c29a1cf9b48f588e60a7612209
Hi Maintainers,
It seems the patches get reviewed tag for a long time, can you give this
series further comment or help me to merge them ?
Thanks very much.
BRs
Ziyue
^ permalink raw reply [flat|nested] 5+ messages in thread