[PATCH v7 06/10] PCI: imx6: Improve comment for workaround ERR010728

[Manivannan Sadhasivam]

On Mon, Jul 08, 2024 at 01:08:10PM -0400, Frank Li wrote:
> Improve comment about workaround ERR010728 by using official errata
> document content(https://www.nxp.com/webapp/Download?colCode=IMX7DS_2N09P).
> 
> Signed-off-by: Frank Li <Frank.Li at nxp.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>

- Mani

> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 23 ++++++++++++++++++++---
>  1 file changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 2c60858b74a09..2b95c41f8907e 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -714,9 +714,26 @@ static int imx7d_pcie_core_reset(struct imx_pcie *imx_pcie, bool assert)
>  		return 0;
>  
>  	/*
> -	 * Workaround for ERR010728, failure of PCI-e PLL VCO to
> -	 * oscillate, especially when cold. This turns off "Duty-cycle
> -	 * Corrector" and other mysterious undocumented things.
> +	 * Workaround for ERR010728 (IMX7DS_2N09P, Rev. 1.1, 4/2023):
> +	 *
> +	 * PCIe: PLL may fail to lock under corner conditions.
> +	 *
> +	 * Initial VCO oscillation may fail under corner conditions such as
> +	 * cold temperature which will cause the PCIe PLL fail to lock in the
> +	 * initialization phase.
> +	 *
> +	 * The Duty-cycle Corrector calibration must be disabled.
> +	 *
> +	 * 1. De-assert the G_RST signal by clearing
> +	 *    SRC_PCIEPHY_RCR[PCIEPHY_G_RST].
> +	 * 2. De-assert DCC_FB_EN by writing data “0x29” to the register
> +	 *    address 0x306d0014 (PCIE_PHY_CMN_REG4).
> +	 * 3. Assert RX_EQS, RX_EQ_SEL by writing data “0x48” to the register
> +	 *    address 0x306d0090 (PCIE_PHY_CMN_REG24).
> +	 * 4. Assert ATT_MODE by writing data “0xbc” to the register
> +	 *    address 0x306d0098 (PCIE_PHY_CMN_REG26).
> +	 * 5. De-assert the CMN_RST signal by clearing register bit
> +	 *    SRC_PCIEPHY_RCR[PCIEPHY_BTN]
>  	 */
>  
>  	if (likely(imx_pcie->phy_base)) {
> 
> -- 
> 2.34.1
> 

-- 
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