Re: [PATCH 08/12] PCI: tegra: Wait for DLLP to finish before entering L1 or L2

Vidya Sagar
2017-10-29T09:42:48Z

On Saturday 28 October 2017 12:59 AM, Manikanta Maddireddy wrote:
> Set required bit to have LTSSM wait for DLLP to finish before entering L1
> or L2. This avoids truncation of PM messages which results in receiver
> errors.
>
> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
> ---
> drivers/pci/host/pci-tegra.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
> index b8cac871712b..6028d5f3d5bb 100644
> --- a/drivers/pci/host/pci-tegra.c
> +++ b/drivers/pci/host/pci-tegra.c
> @@ -217,6 +217,9 @@
> #define RP_VEND_CTL1 0xf48
> #define RP_VEND_CTL1_ERPT (1 << 13)
>
> +#define RP_VEND_XP_BIST 0xf4c
> +#define RP_VEND_XP_BIST_GOTO_L1_L2_AFTER_DLLP_DONE (1 << 28)
> +
BIT macro is preferred here.
> #define RP_VEND_CTL2 0x00000fa8
> #define RP_VEND_CTL2_PCA_ENABLE (1 << 7)
>
> @@ -2160,6 +2163,13 @@ static void tegra_pcie_apply_sw_fixup(struct tegra_pcie_port *port)
> value |= RP_VEND_XP_OPPORTUNISTIC_ACK;
> value |= RP_VEND_XP_OPPORTUNISTIC_UPDATEFC;
> writel(value, port->base + RP_VEND_XP);
> +
> + /* LTSSM will wait for DLLP to finish before entering L1 or L2,
> + * to avoid truncation of PM messages which results in receiver errors
> + */
> + value = readl(port->base + RP_VEND_XP_BIST);
> + value |= RP_VEND_XP_BIST_GOTO_L1_L2_AFTER_DLLP_DONE;
> + writel(value, port->base + RP_VEND_XP_BIST);
> }
> /*
> * FIXME: If there are no PCIe cards attached, then calling this function