linux-kernel - RE: [PATCHv3 17/27] PCI: mobiveil: fix the checking of valid device

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Date:   Mon, 18 Feb 2019 07:04:15 +0000
From:   "Z.q. Hou" <zhiqiang.hou@....com>
To:     Subrahmanya Lingappa <l.subrahmanya@...iveil.co.in>
CC:     "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        Leo Li <leoyang.li@....com>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "catalin.marinas@....com" <catalin.marinas@....com>,
        "will.deacon@....com" <will.deacon@....com>,
        Mingkai Hu <mingkai.hu@....com>,
        "M.h. Lian" <minghuan.lian@....com>,
        Xiaowei Bao <xiaowei.bao@....com>
Subject: RE: [PATCHv3 17/27] PCI: mobiveil: fix the checking of valid device

Hi Subbu,

Thanks a lot for your comments!

> -----Original Message-----
> From: Subrahmanya Lingappa <l.subrahmanya@...iveil.co.in>
> Sent: 2019年2月8日 20:41
> To: Z.q. Hou <zhiqiang.hou@....com>
> Cc: linux-pci@...r.kernel.org; linux-arm-kernel@...ts.infradead.org;
> devicetree@...r.kernel.org; linux-kernel@...r.kernel.org;
> bhelgaas@...gle.com; robh+dt@...nel.org; mark.rutland@....com;
> shawnguo@...nel.org; Leo Li <leoyang.li@....com>;
> lorenzo.pieralisi@....com; catalin.marinas@....com;
> will.deacon@....com; Mingkai Hu <mingkai.hu@....com>; M.h. Lian
> <minghuan.lian@....com>; Xiaowei Bao <xiaowei.bao@....com>
> Subject: Re: [PATCHv3 17/27] PCI: mobiveil: fix the checking of valid device
> 
> ZQ,
> 
> On Tue, Jan 29, 2019 at 1:40 PM Z.q. Hou <zhiqiang.hou@....com> wrote:
> >
> > From: Hou Zhiqiang <Zhiqiang.Hou@....com>
> >
> > Avoid to issue CFG transactions to link partner when the PCIe link is
> > not up. And allow CFG transactions to all functions of Endpoint
> > implemented multiple functions.
> >
> > Fixes: 9af6bcb11e12 ("PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP
> > driver")
> > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@....com>
> > Reviewed-by: Minghuan Lian <Minghuan.Lian@....com>
> > ---
> > V3:
> >  - No change
> >
> >  drivers/pci/controller/mobiveil/pcie-mobiveil-host.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c
> > b/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c
> > index dc5324d94466..1ae82e790562 100644
> > --- a/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c
> > +++ b/drivers/pci/controller/mobiveil/pcie-mobiveil-host.c
> > @@ -29,6 +29,10 @@ static bool mobiveil_pcie_valid_device(struct
> > pci_bus *bus, unsigned int devfn)  {
> >         struct mobiveil_pcie *pcie = bus->sysdata;
> >
> > +       /* If there is no link, then there is no device */
> > +       if (bus->number > pcie->rp.root_bus_nr
> && !mobiveil_pcie_link_up(pcie))
> > +               return false;
> > +
> >         /* Only one device down on each root port */
> >         if ((bus->number == pcie->rp.root_bus_nr) && (devfn > 0))
> >                 return false;
> > @@ -37,7 +41,7 @@ static bool mobiveil_pcie_valid_device(struct pci_bus
> *bus, unsigned int devfn)
> >          * Do not read more than one device on the bus directly
> >          * attached to RC
> >          */
> > -       if ((bus->primary == pcie->rp.root_bus_nr) && (devfn > 0))
> > +       if ((bus->primary == pcie->rp.root_bus_nr) && (PCI_SLOT(devfn)
> > + > 0))
> here change "primary" to "number", as it's a bug in the original driver too.

No, I think it should not change to "number", as this is to check the EP directly attached to RC, so if we change it to "bus->number", the "pcie->rp.root_bus_nr" should be changed to "pcie->rp.root_bus_nr +1" correspondingly.

> 
> >                 return false;
> >
> >         return true;
> > --
> > 2.17.1
> >

Thanks,
Zhiqiang