Re: [PATCH] PCI: rcar-gen4: Isolate 256B MRRS limit only to R-Car Gen4 SoC PCIe controller

[Marek Vasut]

On 10/30/26 7:06 AM, Manivannan Sadhasivam wrote:

Hello Manivannan,

> > diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > index 9a64a9f4ab0d1..1e4405181eef3 100644
> > --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > @@ -99,6 +99,7 @@ struct rcar_gen4_pcie_drvdata {
> >   	int (*ltssm_control)(struct rcar_gen4_pcie *rcar, bool enable);
> >   	int (*speed_control)(struct rcar_gen4_pcie *rcar);
> >   	enum dw_pcie_device_mode mode;
> > +	bool mrrs_256b_limit;
> >   };
> >   
> >   struct rcar_gen4_pcie {
> > @@ -663,7 +664,7 @@ static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp)
> >   	if (ret)
> >   		return ret;
> >   
> > -	if (pp->bridge)
> > +	if (rcar->drvdata->mrrs_256b_limit && pp->bridge)
> >   		pp->bridge->enable_device = rcar_gen4_pcie_enable_device;
>
> I'd suggest moving this check inside enable_device() callback to make it clear
> where exactly the skipping happens.

If we do that, we would end up with assigning a callback which always 
does nothing on R-Car Gen5 (SoC with rcar->drvdata->mrrs_256b_limit = 
false), that is not good. I think it is better to simply not assign the 
callback on R-Car Gen5 at all. Hence this here.

--
Best regards,
Marek Vasut