Re: [PATCH] PCI: dwc: move dw_pcie_iatu_detect() after host_init callback

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Wed, Apr 07, 2021 at 04:37:15PM +0300, Dmitry Baryshkov wrote:
> Hi,
> 
> On Wed, 7 Apr 2021 at 16:12, Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> wrote:
> >
> > The commit 9ea483375ded ("PCI: dwc: Move forward the iATU detection
> > process") broke PCIe support on Qualcomm SM8250 (and maybe other
> > platforms) since it moves the call to dw_pcie_iatu_detect() at the
> > beginning of the dw_pcie_host_init(), before ops->host_init() callback.
> > Accessing PCIe registers at this point causes the board to reboot since
> > not all clocks are enabled, making PCIe registers unavailable.
> >
> > Move dw_pcie_iatu_detect() call after calling ops->host_init() callback,
> > so that all register are accessible.
> >
> > Cc: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
> > Fixes: 9ea483375ded ("PCI: dwc: Move forward the iATU detection process")
> 
> Please disregard the Fixes: tag here, the patch in question came to me
> from a local tree, which I failed to notice.
> The patch still applies on top of the previously dropped patch (and it
> is the same fix as the one proposed for exynos by Marek Szyprowski at
> https://lore.kernel.org/linux-pci/b777ab31-e0b9-bbc0-9631-72b93097919e@samsung.com/.

Ok. Can you integrate Bjorn's changes (reported in the thread above) to
the commit log and resend it with Marek in CC so that I can merge it
please ?

Thanks,
Lorenzo

> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > ---
> >  drivers/pci/controller/dwc/pcie-designware-host.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> > index 52f6887179cd..24192b40e3a2 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> > @@ -319,8 +319,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
> >                         return PTR_ERR(pci->dbi_base);
> >         }
> >
> > -       dw_pcie_iatu_detect(pci);
> > -
> >         bridge = devm_pci_alloc_host_bridge(dev, 0);
> >         if (!bridge)
> >                 return -ENOMEM;
> > @@ -400,6 +398,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
> >                 if (ret)
> >                         goto err_free_msi;
> >         }
> > +       dw_pcie_iatu_detect(pci);
> >
> >         dw_pcie_setup_rc(pp);
> >         dw_pcie_msi_init(pp);
> > --
> > 2.30.2
> >
> 
> 
> -- 
> With best wishes
> Dmitry