On Tue, Mar 29, 2022 at 11:07:15AM +0800, Jianjun Wang wrote:
> Print current LTSSM state when PCIe link down instead of the register
> value, make it easier to get the link status.
>
> Signed-off-by: Jianjun Wang <jianjun.wang@xxxxxxxxxxxx>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> ---
> Changes in v2:
> Print both of the register value and the LTSSM state.
Applied to pci/ctrl/mediatek-gen3 for v5.20, thanks!
> ---
> drivers/pci/controller/pcie-mediatek-gen3.c | 41 ++++++++++++++++++++-
> 1 file changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
> index 6745076a02b9..c24e03c198b7 100644
> --- a/drivers/pci/controller/pcie-mediatek-gen3.c
> +++ b/drivers/pci/controller/pcie-mediatek-gen3.c
> @@ -153,6 +153,37 @@ struct mtk_gen3_pcie {
> DECLARE_BITMAP(msi_irq_in_use, PCIE_MSI_IRQS_NUM);
> };
>
> +/* LTSSM state in PCIE_LTSSM_STATUS_REG bit[28:24] */
> +static const char *const ltssm_str[] = {
> + "detect.quiet", /* 0x00 */
> + "detect.active", /* 0x01 */
> + "polling.active", /* 0x02 */
> + "polling.compliance", /* 0x03 */
> + "polling.configuration", /* 0x04 */
> + "config.linkwidthstart", /* 0x05 */
> + "config.linkwidthaccept", /* 0x06 */
> + "config.lanenumwait", /* 0x07 */
> + "config.lanenumaccept", /* 0x08 */
> + "config.complete", /* 0x09 */
> + "config.idle", /* 0x0A */
> + "recovery.receiverlock", /* 0x0B */
> + "recovery.equalization", /* 0x0C */
> + "recovery.speed", /* 0x0D */
> + "recovery.receiverconfig", /* 0x0E */
> + "recovery.idle", /* 0x0F */
> + "L0", /* 0x10 */
> + "L0s", /* 0x11 */
> + "L1.entry", /* 0x12 */
> + "L1.idle", /* 0x13 */
> + "L2.idle", /* 0x14 */
> + "L2.transmitwake", /* 0x15 */
> + "disable", /* 0x16 */
> + "loopback.entry", /* 0x17 */
> + "loopback.active", /* 0x18 */
> + "loopback.exit", /* 0x19 */
> + "hotreset", /* 0x1A */
> +};
> +
> /**
> * mtk_pcie_config_tlp_header() - Configure a configuration TLP header
> * @bus: PCI bus to query
> @@ -327,8 +358,16 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie)
> !!(val & PCIE_PORT_LINKUP), 20,
> PCI_PM_D3COLD_WAIT * USEC_PER_MSEC);
> if (err) {
> + const char *ltssm_state;
> + int ltssm_index;
> +
> val = readl_relaxed(pcie->base + PCIE_LTSSM_STATUS_REG);
> - dev_err(pcie->dev, "PCIe link down, ltssm reg val: %#x\n", val);
> + ltssm_index = PCIE_LTSSM_STATE(val);
> + ltssm_state = ltssm_index >= ARRAY_SIZE(ltssm_str) ?
> + "Unknown state" : ltssm_str[ltssm_index];
> + dev_err(pcie->dev,
> + "PCIe link down, current ltssm state: %s (%#x)\n",
> + ltssm_state, val);
> return err;
> }
>
> --
> 2.18.0
>
>
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