Re: [PATCH 2/2] PCI: dwc: Add support to configure for ECRC

[Vidya Sagar <vidyas@xxxxxxxxxx>]

On 10/26/2020 2:19 AM, Jingoo Han wrote:
> External email: Use caution opening links or attachments
>
>
> On 10/25/20, 3:31 AM, Vidya Sagar wrote:
> > DesignWare core has a TLP digest (TD) override bit in one of the control
> > registers of ATU. This bit also needs to be programmed for proper ECRC
> > functionality. This is currently identified as an issue with DesignWare
> > IP version 4.90a. This patch does the required programming in ATU upon
> > querying the system policy for ECRC.
> >
> > Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> > ---
> >   drivers/pci/controller/dwc/pcie-designware.c | 8 ++++++--
> >   drivers/pci/controller/dwc/pcie-designware.h | 2 ++
> >   2 files changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> > index b5e438b70cd5..810dcbdbe869 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware.c
> > @@ -245,7 +245,7 @@ static void dw_pcie_prog_outbound_atu_unroll(struct dw_pcie *pci, u8 func_no,
> >                                 lower_32_bits(pci_addr));
> >        dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_UPPER_TARGET,
> >                                 upper_32_bits(pci_addr));
> > -     val = type | PCIE_ATU_FUNC_NUM(func_no);
> > +     val = type | PCIE_ATU_FUNC_NUM(func_no) | pci->td << PCIE_ATU_TD_SHIFT;
> >        val = upper_32_bits(size - 1) ?
> >                val | PCIE_ATU_INCREASE_REGION_SIZE : val;
> >        dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_REGION_CTRL1, val);
> > @@ -295,7 +295,8 @@ static void __dw_pcie_prog_outbound_atu(struct dw_pcie *pci, u8 func_no,
> >        dw_pcie_writel_dbi(pci, PCIE_ATU_UPPER_TARGET,
> >                           upper_32_bits(pci_addr));
> >        dw_pcie_writel_dbi(pci, PCIE_ATU_CR1, type |
> > -                        PCIE_ATU_FUNC_NUM(func_no));
> > +                        PCIE_ATU_FUNC_NUM(func_no) |
> > +                        pci->td << PCIE_ATU_TD_SHIFT);
> >        dw_pcie_writel_dbi(pci, PCIE_ATU_CR2, PCIE_ATU_ENABLE);
> >
> >        /*
> > @@ -565,6 +566,9 @@ void dw_pcie_setup(struct dw_pcie *pci)
> >        dev_dbg(pci->dev, "iATU unroll: %s\n", pci->iatu_unroll_enabled ?
> >                "enabled" : "disabled");
> >
> > +     if (pci->version == 0x490A)
> > +             pci->td = pcie_is_ecrc_enabled();
> > +
> >        if (pci->link_gen > 0)
> >                dw_pcie_link_set_max_speed(pci, pci->link_gen);
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> > index 21dd06831b50..d34723e42e79 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > @@ -90,6 +90,7 @@
> >   #define PCIE_ATU_TYPE_IO             0x2
> >   #define PCIE_ATU_TYPE_CFG0           0x4
> >   #define PCIE_ATU_TYPE_CFG1           0x5
> > +#define PCIE_ATU_TD_SHIFT            8
> >   #define PCIE_ATU_FUNC_NUM(pf)           ((pf) << 20)
> >   #define PCIE_ATU_CR2                 0x908
> >   #define PCIE_ATU_ENABLE                      BIT(31)
> > @@ -276,6 +277,7 @@ struct dw_pcie {
> >        int                     num_lanes;
> >        int                     link_gen;
> >        u8                      n_fts[2];
> > +     bool                    td;     /* TLP Digest (for ECRC purpose) */
>
> If possible, don't add a new variable to 'dw_pcie' structure.
> Please find a way to set TD bit without adding a new variable to 'dw_pcie' structure'.

I can use pcie_is_ecrc_enabled() directly in place of pci->td. That 
should be fine right? BTW, curious to know if there is any specific 
reason behind asking not to add any new variables to 'dw_pcie' structure?

> Best regards,
> Jingoo Han
>
> >   };
> >
> >   #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)
> > --
> > 2.17.1