[RFC PATCH v5 2/4] PCI: rockchip: Set Target Link Speed before retraining

[Robin Murphy]

On 2025-06-13 6:03 pm, Geraldo Nascimento wrote:
> Current code may fail Gen2 retraining if Target Link Speed
> is set to 2.5 GT/s in Link Control and Status Register 2.
> Set it to 5.0 GT/s accordingly.

I have max-link-speed overridden to 2 in my local DTB, and indeed this 
seems to make my NVMe report a 5.0 GT/s link where previously it was 
still downgrading to 2.5, so:

Tested-by: Robin Murphy <robin.murphy at arm.com>

> Signed-off-by: Geraldo Nascimento <geraldogabriel at gmail.com>
> ---
>   drivers/pci/controller/pcie-rockchip-host.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
> index 8489d51e01ca..467e3fc377f7 100644
> --- a/drivers/pci/controller/pcie-rockchip-host.c
> +++ b/drivers/pci/controller/pcie-rockchip-host.c
> @@ -341,6 +341,10 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
>   		 * Enable retrain for gen2. This should be configured only after
>   		 * gen1 finished.
>   		 */
> +		status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_CR + PCI_EXP_LNKCTL2);
> +		status &= ~PCI_EXP_LNKCTL2_TLS;
> +		status |= PCI_EXP_LNKCTL2_TLS_5_0GT;
> +		rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_CR + PCI_EXP_LNKCTL2);
>   		rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_CR + PCI_EXP_LNKCTL2);
>   		status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_CR + PCI_EXP_LNKCTL);
>   		status |= PCI_EXP_LNKCTL_RL;