[PATCH v2 3/6] PCI: imx6: Workaround i.MX95 PCIe may not exit L23 ready

[Frank Li]

On Wed, Mar 26, 2025 at 03:59:12PM +0800, Richard Zhu wrote:
> ERR051624: The Controller Without Vaux Cannot Exit L23 Ready Through Beacon
> or PERST# De-assertion
>
> When the auxiliary power is not available, the controller cannot exit from
> L23 Ready with beacon or PERST# de-assertion when main power is not
> removed.
>
> Workaround: Set SS_RW_REG_1[SYS_AUX_PWR_DET] to 1.
>
> Signed-off-by: Richard Zhu <hongxing.zhu at nxp.com>

Reviewed-by: Frank Li <Frank.Li at nxp.com>

> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 13e53311cc0e..fbab5a4621aa 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -48,6 +48,8 @@
>  #define IMX95_PCIE_SS_RW_REG_0			0xf0
>  #define IMX95_PCIE_REF_CLKEN			BIT(23)
>  #define IMX95_PCIE_PHY_CR_PARA_SEL		BIT(9)
> +#define IMX95_PCIE_SS_RW_REG_1			0xf4
> +#define IMX95_PCIE_SYS_AUX_PWR_DET		BIT(31)
>
>  #define IMX95_PE0_GEN_CTRL_1			0x1050
>  #define IMX95_PCIE_DEVICE_TYPE			GENMASK(3, 0)
> @@ -227,6 +229,19 @@ static unsigned int imx_pcie_grp_offset(const struct imx_pcie *imx_pcie)
>
>  static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie)
>  {
> +	/*
> +	 * ERR051624: The Controller Without Vaux Cannot Exit L23 Ready
> +	 * Through Beacon or PERST# De-assertion
> +	 *
> +	 * When the auxiliary power is not available, the controller
> +	 * cannot exit from L23 Ready with beacon or PERST# de-assertion
> +	 * when main power is not removed.
> +	 *
> +	 * Workaround: Set SS_RW_REG_1[SYS_AUX_PWR_DET] to 1.
> +	 */
> +	regmap_set_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_1,
> +			IMX95_PCIE_SYS_AUX_PWR_DET);
> +
>  	regmap_update_bits(imx_pcie->iomuxc_gpr,
>  			IMX95_PCIE_SS_RW_REG_0,
>  			IMX95_PCIE_PHY_CR_PARA_SEL,
> --
> 2.37.1
>