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

[Z.q. Hou]

Hi Subbu,

Thanks a lot for your comments!

> -----Original Message-----
> From: Subrahmanya Lingappa <l.subrahmanya@xxxxxxxxxxxxxx>
> Sent: 2019å2æ8æ 20:41
> To: Z.q. Hou <zhiqiang.hou@xxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> bhelgaas@xxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx;
> shawnguo@xxxxxxxxxx; Leo Li <leoyang.li@xxxxxxx>;
> lorenzo.pieralisi@xxxxxxx; catalin.marinas@xxxxxxx;
> will.deacon@xxxxxxx; Mingkai Hu <mingkai.hu@xxxxxxx>; M.h. Lian
> <minghuan.lian@xxxxxxx>; Xiaowei Bao <xiaowei.bao@xxxxxxx>
> 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@xxxxxxx> wrote:
> >
> > From: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
> >
> > 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@xxxxxxx>
> > Reviewed-by: Minghuan Lian <Minghuan.Lian@xxxxxxx>
> > ---
> > 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