linux-kernel - Re: [PATCH v11 10/11] PCI: dwc: Print warning message when cpu_addr

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Message-ID: <aEr3nGCqRuyIwA37@lizhi-Precision-Tower-5810>
Date: Thu, 12 Jun 2025 11:51:56 -0400
From: Frank Li <Frank.li@....com>
To: Manivannan Sadhasivam <mani@...nel.org>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, Rob Herring <robh@...nel.org>,
	Saravana Kannan <saravanak@...gle.com>,
	Jingoo Han <jingoohan1@...il.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Richard Zhu <hongxing.zhu@....com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, imx@...ts.linux.dev,
	Niklas Cassel <cassel@...nel.org>
Subject: Re: [PATCH v11 10/11] PCI: dwc: Print warning message when
 cpu_addr_fixup() exists

On Thu, Jun 12, 2025 at 08:16:03PM +0530, Manivannan Sadhasivam wrote:
> On Thu, Mar 13, 2025 at 11:38:46AM -0400, Frank Li wrote:
> > If the parent 'ranges' property in DT correctly describes the address
> > translation, the cpu_addr_fixup() callback is not needed. Print a warning
> > message to inform users to correct their DTB files and prepare to remove
> > cpu_addr_fixup().
> >
>
> This patch seem to have dropped, but I do see a value in printing the warning to
> encourage developers/users to fix the DTB in some way. Since we fixed the driver
> to parse the DT 'ranges' properly, the presence of cpu_addr_fixup() callback
> indicates that the translation is not properly described in DT. So DT has to be
> fixed.

This patch already in mainline with Bjorn's fine tuned at when merge.

	fixup = pci->ops ? pci->ops->cpu_addr_fixup : NULL;
        if (fixup) {
                fixup_addr = fixup(pci, cpu_phys_addr);
                if (reg_addr == fixup_addr) {
                        dev_info(dev, "%s reg[%d] %#010llx == %#010llx == fixup(cpu %#010llx); %ps is redundant with this devicetree\n",
                                 reg_name, index, reg_addr, fixup_addr,
                                 (unsigned long long) cpu_phys_addr, fixup);
                } else {
                        dev_warn(dev, "%s reg[%d] %#010llx != %#010llx == fixup(cpu %#010llx); devicetree is broken\n",
                                 reg_name, index, reg_addr, fixup_addr,
                                 (unsigned long long) cpu_phys_addr);
                        reg_addr = fixup_addr;
                }

                return cpu_phys_addr - reg_addr;
        }

I have not seen this "dev_warn(pci->dev, "cpu_addr_fixup() usage detected. Please fix your DTB!\n");"

Frank

>
> Bjorn, thoughts?
>
> - Mani
>
> > Signed-off-by: Frank Li <Frank.Li@....com>
> > ---
> > change from v10 to v11
> > - change to dev_warn()
> > - Bjorn: this is opitional patches to encourage user fix their dtb file.
> >
> > change from v9 to v10
> > - new patch
> > ---
> >  drivers/pci/controller/dwc/pcie-designware.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> > index 8b546131b97f6..d4dc8bf06d4c1 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware.c
> > @@ -1125,6 +1125,8 @@ int dw_pcie_init_parent_bus_offset(struct dw_pcie *pci, const char *reg_name,
> >
> >  	fixup = pci->ops->cpu_addr_fixup;
> >  	if (fixup) {
> > +		dev_warn(pci->dev, "cpu_addr_fixup() usage detected. Please fix your DTB!\n");
> > +
> >  		fixup_addr = fixup(pci, cpu_phy_addr);
> >  		if (reg_addr == fixup_addr) {
> >  			dev_warn(dev, "%#010llx %s reg[%d] == %#010llx; %ps is redundant\n",
> >
> > --
> > 2.34.1
> >
>
> --
> மணிவண்ணன் சதாசிவம்