--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -776,7 +776,6 @@ static int imx7d_pcie_core_reset(struct imx_pcie *imx_pcie, bool assert)
static void imx_pcie_assert_core_reset(struct imx_pcie *imx_pcie)
{
reset_control_assert(imx_pcie->pciephy_reset);
- reset_control_assert(imx_pcie->apps_reset);
if (imx_pcie->drvdata->core_reset)
imx_pcie->drvdata->core_reset(imx_pcie, true);
@@ -788,7 +787,6 @@ static void imx_pcie_assert_core_reset(struct imx_pcie *imx_pcie)
static int imx_pcie_deassert_core_reset(struct imx_pcie *imx_pcie)
{
reset_control_deassert(imx_pcie->pciephy_reset);
- reset_control_deassert(imx_pcie->apps_reset);
if (imx_pcie->drvdata->core_reset)
imx_pcie->drvdata->core_reset(imx_pcie, false);
@@ -1176,6 +1174,9 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
}
}
+ /* Make sure that PCIe LTSSM is cleared */
+ imx_pcie_ltssm_disable(dev);
+
ret = imx_pcie_deassert_core_reset(imx_pcie);
if (ret < 0) {
dev_err(dev, "pcie deassert core reset failed: %d\n", ret);
> I notice the sequence of events here is:
> imx_pcie_assert_core_reset asserts apps_reset (disables LTSSM)
> imx_pcie_deassert_core_reset deasserts apps_reset (enables LTSSM)
> imx_pcie_ltssm_enable deasserts apps_reset (enables LTSSM; this is where it
> hangs on imx8mp)
>
> Is there perhaps some issue with de-asserting this (enabling LTSSM) when it's
> already in this state?
[Richard Zhu]The apps_reset is updated by src driver by regmap_update_bits().
I can't find the exceptions to update one bit, already has the according value.
Best Regards
Richard Zhu
>
> In the case where downstream devices do not enumerate some investigation
> points to them not being happy that the link drops so perhaps deasserting
> apps_reset when its already asserted drops the link and restarts it?
>
> Best Regards,
>
> Tim
