From: Ziyue Zhang <ziyue.zhang@oss.qualcomm.com>
To: andersson@kernel.org, konradybcio@kernel.org, robh@kernel.org,
krzk+dt@kernel.org, conor+dt@kernel.org, jingoohan1@gmail.com,
mani@kernel.org, lpieralisi@kernel.org, kwilczynski@kernel.org,
bhelgaas@google.com, johan+linaro@kernel.org, vkoul@kernel.org,
kishon@kernel.org, neil.armstrong@linaro.org,
abel.vesa@linaro.org, kw@linux.com
Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-phy@lists.infradead.org, qiang.yu@oss.qualcomm.com,
quic_krichai@quicinc.com, quic_vbadigan@quicinc.com,
Ziyue Zhang <ziyue.zhang@oss.qualcomm.com>
Subject: [PATCH v4 1/3] PCI: qcom: Add equalization settings for 8.0 GT/s
Date: Mon, 14 Jul 2025 16:21:08 +0800 [thread overview]
Message-ID: <20250714082110.3890821-2-ziyue.zhang@oss.qualcomm.com> (raw)
In-Reply-To: <20250714082110.3890821-1-ziyue.zhang@oss.qualcomm.com>
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
next prev parent reply other threads:[~2025-07-14 8:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
2025-07-14 8:21 ` [PATCH v4 2/3] PCI: qcom: fix macro typo for CURSOR 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
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