[PATCH 6.1 0827/1146] phy: qcom-qmp-pcie: Fix high latency with 4x2 PHY when ASPM is enabled

Greg Kroah-Hartman
2022-12-28T16:44:50Z

From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

[ Upstream commit 9ddcd920f8edfe65c3670fbd0b49db00e1e562fe ]

The PCIe QMP 4x2 RC PHY generates high latency when ASPM is enabled. This
seem to be fixed by clearing the QPHY_V5_20_PCS_PCIE_PRESET_P10_POST
register of the pcs_misc register space.

Fixes: 2c91bf6bf290 ("phy: qcom-qmp: Add SM8450 PCIe1 PHY support")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20221102081835.41892-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 1 +
drivers/phy/qualcomm/phy-qcom-qmp-pcs-pcie-v5_20.h | 1 +
2 files changed, 2 insertions(+)

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
index 3c5c4a4412e0..5a17cda1a6b8 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
@@ -1308,6 +1308,7 @@ static const struct qmp_phy_init_tbl sm8450_qmp_gen4x2_pcie_pcs_misc_tbl[] = {
static const struct qmp_phy_init_tbl sm8450_qmp_gen4x2_pcie_rc_pcs_misc_tbl[] = {
QMP_PHY_INIT_CFG(QPHY_V5_20_PCS_PCIE_ENDPOINT_REFCLK_DRIVE, 0xc1),
QMP_PHY_INIT_CFG(QPHY_V5_20_PCS_PCIE_OSC_DTCT_ACTIONS, 0x00),
+ QMP_PHY_INIT_CFG(QPHY_V5_20_PCS_PCIE_PRESET_P10_POST, 0x00),
};

static const struct qmp_phy_init_tbl sm8450_qmp_gen4x2_pcie_ep_serdes_tbl[] = {
diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcs-pcie-v5_20.h b/drivers/phy/qualcomm/phy-qcom-qmp-pcs-pcie-v5_20.h
index c9fa90b45475..3d9713d348fe 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcs-pcie-v5_20.h
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcs-pcie-v5_20.h
@@ -11,6 +11,7 @@
#define QPHY_V5_20_PCS_PCIE_OSC_DTCT_MODE2_CONFIG5 0x084
#define QPHY_V5_20_PCS_PCIE_OSC_DTCT_ACTIONS 0x090
#define QPHY_V5_20_PCS_PCIE_EQ_CONFIG1 0x0a0
+#define QPHY_V5_20_PCS_PCIE_PRESET_P10_POST 0x0e0
#define QPHY_V5_20_PCS_PCIE_G4_EQ_CONFIG5 0x108
#define QPHY_V5_20_PCS_PCIE_G4_PRE_GAIN 0x15c
#define QPHY_V5_20_PCS_PCIE_RX_MARGINING_CONFIG3 0x184
--
2.35.1