Re: [PATCH 2/2] PCI: dwc: ep: Mirror the max link width and speed fields to all functions

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Feb 18, 2026 at 07:08:20PM +0530, Manivannan Sadhasivam wrote:
> On Mon, Feb 02, 2026 at 12:57:58PM +0530, Aksh Garg wrote:
> > PCIe r6.0, section 7.5.3.6 states that for multi-function devices, the
> > Max Link Width and Max Link Speed fields in the Link Capabilities
> > Register must report the same values for all functions.
> ...

> > @@ -1102,6 +1103,27 @@ static void dw_pcie_ep_init_non_sticky_registers(struct dw_pcie *pci)
> >  		dw_pcie_ep_init_rebar_registers(ep, func_no);
> >  
> >  	dw_pcie_setup(pci);
> > +
> > +	/*
> > +	 * PCIe r6.0, section 7.5.3.6 states that for multi-function endpoints,
> > +	 * max link width and speed fields must report same values for all functions.
> > +	 * However, dw_pcie_setup() programs these fields only for physical function 0.
> > +	 * Hence, mirror these fields to all other physical functions as well.
> > +	 */
> > +	if (funcs > 1) {
> > +		offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> > +		ref_lnkcap = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP);
> > +		ref_lnkcap &= PCI_EXP_LNKCAP_MLW | PCI_EXP_LNKCAP_SLS;
> 
> Use FIELD_* macros please.
> 
> > +
> > +		for (func_no = 1; func_no < funcs; func_no++) {
> > +			offset = dw_pcie_ep_find_capability(ep, func_no, PCI_CAP_ID_EXP);
> > +			lnkcap = dw_pcie_ep_readl_dbi(ep, func_no, offset + PCI_EXP_LNKCAP);
> > +			lnkcap &= ~(PCI_EXP_LNKCAP_MLW | PCI_EXP_LNKCAP_SLS);
> > +			lnkcap |= ref_lnkcap;

I think this can also use FIELD_MODIFY().

> > +			dw_pcie_ep_writel_dbi(ep, func_no, offset + PCI_EXP_LNKCAP, lnkcap);
> > +		}
> > +	}
> > +
> >  	dw_pcie_dbi_ro_wr_dis(pci);
> >  }