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Once the clock is stable, ref_clk_en can be asserted. For lower power states where the reference clock to the PHY is disabled, ref_clk_en should also be de-asserted. Move the ref_clk_en bit manipulation into imx95_pcie_enable_ref_clk() to ensure the reference clock stabilizes before ref_clk_en is asserted and before the PHY reset is de-asserted. This aligns with the timing requirements specified in the PHY documentation. Fixes: d8574ce57d76 ("PCI: imx6: Add external reference clock input mode support") Cc: Signed-off-by: Richard Zhu --- drivers/pci/controller/dwc/pci-imx6.c | 40 +++++++++++++++++++-------- 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index c57f18d9e4ffa..c3e623aa18bc2 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -268,8 +268,6 @@ static int imx95_pcie_init_pre_reset(struct imx_pcie *imx_pcie) static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie) { - bool ext = imx_pcie->enable_ext_refclk; - /* * ERR051624: The Controller Without Vaux Cannot Exit L23 Ready * Through Beacon or PERST# De-assertion @@ -288,10 +286,6 @@ static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie) IMX95_PCIE_PHY_CR_PARA_SEL, IMX95_PCIE_PHY_CR_PARA_SEL); - regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_0, - IMX95_PCIE_REF_CLKEN, - ext ? 0 : IMX95_PCIE_REF_CLKEN); - return 0; } @@ -740,7 +734,29 @@ static void imx95_pcie_clkreq_override(struct imx_pcie *imx_pcie, bool enable) static int imx95_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable) { + bool ext = imx_pcie->enable_ext_refclk; + imx95_pcie_clkreq_override(imx_pcie, enable); + /* + * The ref_clk_en signal must remain de-asserted until the + * reference clock is running at appropriate frequency, at which + * point this bit can be asserted. For lower power states where + * the reference clock to the PHY is disabled, it may also be + * de-asserted. + * +------------------- -+--------+----------------+ + * | External clock mode | Enable | PCIE_REF_CLKEN | + * +---------------------+--------+----------------+ + * | TRUE | X | 1b'0 | + * +---------------------+--------+----------------+ + * | FALSE | TRUE | 1b'1 | + * +---------------------+--------+----------------+ + * | FALSE | FALSE | 1b'0 | + * +---------------------+--------+----------------+ + */ + regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_0, + IMX95_PCIE_REF_CLKEN, + ext || !enable ? 0 : IMX95_PCIE_REF_CLKEN); + return 0; } @@ -1262,6 +1278,12 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp) } } + ret = imx_pcie_clk_enable(imx_pcie); + if (ret) { + dev_err(dev, "unable to enable pcie clocks: %d\n", ret); + goto err_reg_disable; + } + if (pp->bridge && imx_check_flag(imx_pcie, IMX_PCIE_FLAG_HAS_LUT)) { pp->bridge->enable_device = imx_pcie_enable_device; pp->bridge->disable_device = imx_pcie_disable_device; @@ -1278,12 +1300,6 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp) imx_pcie_configure_type(imx_pcie); - ret = imx_pcie_clk_enable(imx_pcie); - if (ret) { - dev_err(dev, "unable to enable pcie clocks: %d\n", ret); - goto err_reg_disable; - } - if (imx_pcie->phy) { ret = phy_init(imx_pcie->phy); if (ret) { -- 2.37.1