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From:   sundeep subbaraya <sundeep.lkml@gmail.com>
Date:   Mon, 18 Feb 2019 09:29:06 +0530
Message-ID: <CALHRZuprLQcnGAuiBuYph8AmP+PDViL=VpzkFQc5U30HkwHbpg@mail.gmail.com>
Subject: Re: [v3 PATCH 1/2] PCI: read fixed bus numbers in EA for type 1 functions
To:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        Bjorn Helgaas <bhelgaas@google.com>,
        Bjorn Helgaas <helgaas@kernel.org>
Cc:     "Stalley, Sean" <sean.stalley@intel.com>, sgoutham@marvell.com,
        Subbaraya Sundeep <sbhatta@marvell.com>
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Ping.

Thanks,
Sundeep

On Tue, Feb 5, 2019 at 9:30 AM sundeep subbaraya <sundeep.lkml@gmail.com> wrote:
>
> Hi Bjorn,
>
> Any comments?
>
> Thanks,
> Sundeep
>
> On Wed, Jan 23, 2019 at 6:48 PM <sundeep.lkml@gmail.com> wrote:
> >
> > From: Subbaraya Sundeep <sbhatta@marvell.com>
> >
> > As per the spec - ECN_Enhanced_Allocation_23_Oct_2014_Final
> > and section 6.9.1.2, EA capability contains fixed secondary
> > and subordinate bus numbers for type 1 functions.
> > This patch adds support to read the fixed bus numbers
> > from EA capability for bridge.
> >
> > Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
> > ---
> > v3:
> >   As per Bjorn's suggestion placed EA stuff in pci_ea_init and
> >   captured bus numbers in pci_dev
> > v2:
> >   None just added Sean
> >
> >  drivers/pci/pci.c             | 10 ++++++++--
> >  include/linux/pci.h           |  4 ++++
> >  include/uapi/linux/pci_regs.h |  4 ++++
> >  3 files changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index c25acac..484b63e 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -2909,6 +2909,7 @@ void pci_ea_init(struct pci_dev *dev)
> >         u8 num_ent;
> >         int offset;
> >         int i;
> > +       u32 dw;
> >
> >         /* find PCI EA capability in list */
> >         ea = pci_find_capability(dev, PCI_CAP_ID_EA);
> > @@ -2922,9 +2923,14 @@ void pci_ea_init(struct pci_dev *dev)
> >
> >         offset = ea + PCI_EA_FIRST_ENT;
> >
> > -       /* Skip DWORD 2 for type 1 functions */
> > -       if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
> > +       /* Note fixed bus numbers for type 1 functions */
> > +       if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
> > +               pci_read_config_dword(dev, offset, &dw);
> > +               dev->fixed_sec_busnr = dw & PCI_EA_FIXED_SEC_BUS;
> > +               dev->fixed_sub_busnr = (dw & PCI_EA_FIXED_SUB_BUS) >>
> > +                                       PCI_EA_FIXED_SUB_SHIFT;
> >                 offset += 4;
> > +       }
> >
> >         /* parse each EA entry */
> >         for (i = 0; i < num_ent; ++i)
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 65f1d8c..3e9a3ae 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -459,6 +459,10 @@ struct pci_dev {
> >         char            *driver_override; /* Driver name to force a match */
> >
> >         unsigned long   priv_flags;     /* Private flags for the PCI driver */
> > +
> > +       /* bus numbers from EA capability if this device is a bridge */
> > +       u8 fixed_sec_busnr; /* Fixed Secondary Bus number */
> > +       u8 fixed_sub_busnr; /* Fixed Subordinate Bus number */
> >  };
> >
> >  static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
> > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> > index e1e9888..51e9ac0 100644
> > --- a/include/uapi/linux/pci_regs.h
> > +++ b/include/uapi/linux/pci_regs.h
> > @@ -372,6 +372,10 @@
> >  #define PCI_EA_FIRST_ENT_BRIDGE        8       /* First EA Entry for Bridges */
> >  #define  PCI_EA_ES             0x00000007 /* Entry Size */
> >  #define  PCI_EA_BEI            0x000000f0 /* BAR Equivalent Indicator */
> > +/* Fixed Secondary and Subordinate bus numbers in EA for Bridge */
> > +#define   PCI_EA_FIXED_SEC_BUS         0xff
> > +#define   PCI_EA_FIXED_SUB_BUS         0xff00
> > +#define   PCI_EA_FIXED_SUB_SHIFT       8
> >  /* 0-5 map to BARs 0-5 respectively */
> >  #define   PCI_EA_BEI_BAR0              0
> >  #define   PCI_EA_BEI_BAR5              5
> > --
> > 1.8.3.1
> >