On Tue, Dec 15, 2020 at 09:41:47AM -0600, Rob Herring wrote:
> On Tue, Dec 15, 2020 at 02:25:04PM +0100, Mian Yousaf Kaukab wrote:
> > On Tue, Dec 15, 2020 at 05:45:59PM +0530, Vidya Sagar wrote:
> > > Thanks Mian for bringing it to our notice.
> > > Have you tried removing the dw_pcie_setup_rc(pp); call from
> > > pcie-tegra194.c
> > > file on top of linux-next? and does that solve the issue?
> > >
> > > diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c
> > > b/drivers/pci/controller/dwc/pcie-tegra194.c
> > > index 5597b2a49598..1c9e9c054592 100644
> > > --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> > > +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> > > @@ -907,7 +907,7 @@ static void tegra_pcie_prepare_host(struct pcie_port
> > > *pp)
> > > dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF,
> > > val);
> > > }
> > >
> > > - dw_pcie_setup_rc(pp);
> > > + //dw_pcie_setup_rc(pp);
> > I still see the same issue with this change.
> > Reverting b9ac0f9dc8ea works though.
> > >
> > > clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
> > >
> > > I took a quick look at the dw_pcie_setup_rc() implementation and I'm not
> > > sure why calling it second time should create any issue for the
> > > enumeration
> > > of devices behind a switch. Perhaps I need to spend more time to debug
> > > that
> > > part.
> > > In any case, since dw_pcie_setup_rc() is already part of
> > > dw_pcie_host_init(), I think it can be removed from
> > > tegra_pcie_prepare_host() implemention.
>
> I think the 2nd time is making the link go down is my guess. Tegra was
> odd in that its start/stop link functions don't do link handling, so I
> didn't implement those functions and left the link handling in the Tegra
> driver.
>
> Can you try the below patch. It needs some more work as it breaks
> endpoint mode.
That one missed some re-init. Try this one instead
8<--------------------------------------------------------------------
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c
b/drivers/pci/controller/dwc/pcie-tegra194.c
index 5597b2a49598..d8fed3561e91 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -933,14 +933,24 @@ static void tegra_pcie_prepare_host(struct pcie_port *pp)
static int tegra_pcie_dw_host_init(struct pcie_port *pp)
{
- struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
- struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
- u32 val, tmp, offset, speed;
-
pp->bridge->ops = &tegra_pci_ops;
tegra_pcie_prepare_host(pp);
+ return 0;
+}
+
+static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
+{
+ u32 val, offset, speed, tmp;
+ struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
+ struct pcie_port *pp = &pci->pp;
+
+ if (pcie->mode == DW_PCIE_EP_TYPE) {
+ enable_irq(pcie->pex_rst_irq);
+ return 0;
+ }
+
if (dw_pcie_wait_for_link(pci)) {
/*
* There are some endpoints which can't get the link up if
@@ -998,15 +1008,6 @@ static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
return !!(val & PCI_EXP_LNKSTA_DLLLA);
}
-static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
-{
- struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
-
- enable_irq(pcie->pex_rst_irq);
-
- return 0;
-}
-
static void tegra_pcie_dw_stop_link(struct dw_pcie *pci)
{
struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
