Re: [PATCH v3 1/2] PCI: qcom: fix IPQ8074 Gen2 support

[Robert Marko <robimarko@gmail.com>]

On Thu, 23 Jun 2022 at 18:03, Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Thu, Jun 23, 2022 at 05:50:03PM +0200, Robert Marko wrote:
> > Currently the Gen2 port in IPQ8074 will cause the system to hang as its
> > using DBI registers in the .init and those are only accesible after
> > phy_power_on().
> >
> > So solve this by splitting the DBI read/writes to .post_init.
> >
> > Fixes: a0fd361db8e5 ("PCI: dwc: Move "dbi", "dbi2", and "addr_space" resource setup into common code")
>
> Does v5.11 or some v5.11-based stable kernel contain IPQ8074 support?
> If so, I'll mark this for backporting to stable.

Hi Bjorn,
Initial IPQ8074 support was added way back in 4.14.

Note that DTS nodes for both QMP PCI PHY-s and PCIe itself
for IPQ8074 are broken as well.

That is my TODO to clean up and send upstream as well.

Regards,
Robert
>
> > Signed-off-by: Robert Marko <robimarko@gmail.com>
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > ---
> > Changes in v3:
> > * Make sure it applies onto 5.19-rc3
> > * Update the commit description to make it clear this only affects the
> > Gen2 port
> >
> > Changes in v2:
> > * Rebase onto next-20220621
> > ---
> >  drivers/pci/controller/dwc/pcie-qcom.c | 48 +++++++++++++++-----------
> >  1 file changed, 28 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> > index a1f1aca2fb59..24708d5d817d 100644
> > --- a/drivers/pci/controller/dwc/pcie-qcom.c
> > +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> > @@ -1061,9 +1061,7 @@ static int qcom_pcie_init_2_3_3(struct qcom_pcie *pcie)
> >       struct qcom_pcie_resources_2_3_3 *res = &pcie->res.v2_3_3;
> >       struct dw_pcie *pci = pcie->pci;
> >       struct device *dev = pci->dev;
> > -     u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> >       int i, ret;
> > -     u32 val;
> >
> >       for (i = 0; i < ARRAY_SIZE(res->rst); i++) {
> >               ret = reset_control_assert(res->rst[i]);
> > @@ -1120,6 +1118,33 @@ static int qcom_pcie_init_2_3_3(struct qcom_pcie *pcie)
> >               goto err_clk_aux;
> >       }
> >
> > +     return 0;
> > +
> > +err_clk_aux:
> > +     clk_disable_unprepare(res->ahb_clk);
> > +err_clk_ahb:
> > +     clk_disable_unprepare(res->axi_s_clk);
> > +err_clk_axi_s:
> > +     clk_disable_unprepare(res->axi_m_clk);
> > +err_clk_axi_m:
> > +     clk_disable_unprepare(res->iface);
> > +err_clk_iface:
> > +     /*
> > +      * Not checking for failure, will anyway return
> > +      * the original failure in 'ret'.
> > +      */
> > +     for (i = 0; i < ARRAY_SIZE(res->rst); i++)
> > +             reset_control_assert(res->rst[i]);
> > +
> > +     return ret;
> > +}
> > +
> > +static int qcom_pcie_post_init_2_3_3(struct qcom_pcie *pcie)
> > +{
> > +     struct dw_pcie *pci = pcie->pci;
> > +     u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> > +     u32 val;
> > +
> >       writel(SLV_ADDR_SPACE_SZ,
> >               pcie->parf + PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE);
> >
> > @@ -1147,24 +1172,6 @@ static int qcom_pcie_init_2_3_3(struct qcom_pcie *pcie)
> >               PCI_EXP_DEVCTL2);
> >
> >       return 0;
> > -
> > -err_clk_aux:
> > -     clk_disable_unprepare(res->ahb_clk);
> > -err_clk_ahb:
> > -     clk_disable_unprepare(res->axi_s_clk);
> > -err_clk_axi_s:
> > -     clk_disable_unprepare(res->axi_m_clk);
> > -err_clk_axi_m:
> > -     clk_disable_unprepare(res->iface);
> > -err_clk_iface:
> > -     /*
> > -      * Not checking for failure, will anyway return
> > -      * the original failure in 'ret'.
> > -      */
> > -     for (i = 0; i < ARRAY_SIZE(res->rst); i++)
> > -             reset_control_assert(res->rst[i]);
> > -
> > -     return ret;
> >  }
> >
> >  static int qcom_pcie_get_resources_2_7_0(struct qcom_pcie *pcie)
> > @@ -1596,6 +1603,7 @@ static const struct qcom_pcie_ops ops_2_4_0 = {
> >  static const struct qcom_pcie_ops ops_2_3_3 = {
> >       .get_resources = qcom_pcie_get_resources_2_3_3,
> >       .init = qcom_pcie_init_2_3_3,
> > +     .post_init = qcom_pcie_post_init_2_3_3,
> >       .deinit = qcom_pcie_deinit_2_3_3,
> >       .ltssm_enable = qcom_pcie_2_3_2_ltssm_enable,
> >  };
> > --
> > 2.36.1
> >