6.16-stable review patch. If anyone has any objections, please let me know.
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From: Stephan Gerhold stephan.gerhold@linaro.org
commit 6cb8c1f957f674ca20b7d7c96b1f1bb11b83b679 upstream.
Commit 0cc22f5a861c ("phy: qcom: qmp-pcie: Add PHY register retention support") added support for using the "no_csr" reset to skip configuration of the PHY if the init sequence was already applied by the boot firmware. The expectation is that the PHY is only turned on/off by using the "no_csr" reset, instead of powering it down and re-programming it after a full reset.
The boot firmware on X1E does not fully conform to this expectation: If the PCIe3 link fails to come up (e.g. because no PCIe card is inserted), the firmware powers down the PHY using the QPHY_PCS_POWER_DOWN_CONTROL register. The QPHY_START_CTRL register is kept as-is, so the driver assumes the PHY is already initialized and skips the configuration/power up sequence. The PHY won't come up again without clearing the QPHY_PCS_POWER_DOWN_CONTROL, so eventually initialization fails:
qcom-qmp-pcie-phy 1be0000.phy: phy initialization timed-out phy phy-1be0000.phy.0: phy poweron failed --> -110 qcom-pcie 1bd0000.pcie: cannot initialize host qcom-pcie 1bd0000.pcie: probe with driver qcom-pcie failed with error -110
This can be reliably reproduced on the X1E CRD, QCP and Devkit when no card is inserted for PCIe3.
Fix this by checking the QPHY_PCS_POWER_DOWN_CONTROL register in addition to QPHY_START_CTRL. If the PHY is powered down with the register, it doesn't conform to the expectations for using the "no_csr" reset, so we fully re-initialize with the normal reset sequence.
Also check the register more carefully to ensure all of the bits we expect are actually set. A simple !!(readl()) is not enough, because the PHY might be only partially set up with some of the expected bits set.
Cc: stable@vger.kernel.org Fixes: 0cc22f5a861c ("phy: qcom: qmp-pcie: Add PHY register retention support") Signed-off-by: Stephan Gerhold stephan.gerhold@linaro.org Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@oss.qualcomm.com Link: https://lore.kernel.org/r/20250821-phy-qcom-qmp-pcie-nocsr-fix-v3-1-4898db0c... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-)
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c @@ -3064,6 +3064,14 @@ struct qmp_pcie { struct clk_fixed_rate aux_clk_fixed; };
+static bool qphy_checkbits(const void __iomem *base, u32 offset, u32 val) +{ + u32 reg; + + reg = readl(base + offset); + return (reg & val) == val; +} + static inline void qphy_setbits(void __iomem *base, u32 offset, u32 val) { u32 reg; @@ -4332,16 +4340,21 @@ static int qmp_pcie_init(struct phy *phy struct qmp_pcie *qmp = phy_get_drvdata(phy); const struct qmp_phy_cfg *cfg = qmp->cfg; void __iomem *pcs = qmp->pcs; - bool phy_initialized = !!(readl(pcs + cfg->regs[QPHY_START_CTRL])); int ret;
- qmp->skip_init = qmp->nocsr_reset && phy_initialized; /* - * We need to check the existence of init sequences in two cases: - * 1. The PHY doesn't support no_csr reset. - * 2. The PHY supports no_csr reset but isn't initialized by bootloader. - * As we can't skip init in these two cases. + * We can skip PHY initialization if all of the following conditions + * are met: + * 1. The PHY supports the nocsr_reset that preserves the PHY config. + * 2. The PHY was started (and not powered down again) by the + * bootloader, with all of the expected bits set correctly. + * In this case, we can continue without having the init sequence + * defined in the driver. */ + qmp->skip_init = qmp->nocsr_reset && + qphy_checkbits(pcs, cfg->regs[QPHY_START_CTRL], SERDES_START | PCS_START) && + qphy_checkbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL], cfg->pwrdn_ctrl); + if (!qmp->skip_init && !cfg->tbls.serdes_num) { dev_err(qmp->dev, "Init sequence not available\n"); return -ENODATA;