phy: qcom: qmp-pcie: Fix PHY initialization when powered down by firmware
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-v3-1-4898db0cc07c@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
index 95830dc..0fa63b7 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
@@ -3067,6 +3067,14 @@ 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;
@@ -4339,16 +4347,21 @@ 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;
