Re: [PATCH v3 5/7] Silicon/Broadcom/Bcm27xx: Move linkup check into the cfg accessor

["Ard Biesheuvel" <ardb@kernel.org>]

On Sun, 22 Aug 2021 at 15:37, Ard Biesheuvel <ardb@kernel.org> wrote:
>
> On Fri, 20 Aug 2021 at 06:16, Jeremy Linton <jeremy.linton@arm.com> wrote:
> >
> > The existing code fails to create/finish configuring the
> > pcie subsystem if it fails to get a linkup. This is reasonable
> > on the RPi4 because it generally won't happen, and the OS
> > could not see the root port. Now that the OS can see the
> > root port, its a bit odd if it only shows up when
> > something is plugged into the first slot. Lets move the
> > link up check into the config accessor where it will be used
> > to restrict sending CFG TLP's out the port when nothing is
> > plugged in. Thus avoiding a SERROR during probe.
> >
> > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
>
> How will this work when the PCIE/XHCI switch is in 'platform device' mode?
>

Never mind, that only affects the OS whereas this affects UEFI itself only.

> > ---
> >  .../Bcm2711PciHostBridgeLib/Bcm2711PciHostBridgeLibConstructor.c   | 5 -----
> >  .../Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c  | 7 +++++++
> >  2 files changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciHostBridgeLib/Bcm2711PciHostBridgeLibConstructor.c b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciHostBridgeLib/Bcm2711PciHostBridgeLibConstructor.c
> > index 8587d2d36d..4d4c584726 100644
> > --- a/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciHostBridgeLib/Bcm2711PciHostBridgeLibConstructor.c
> > +++ b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciHostBridgeLib/Bcm2711PciHostBridgeLibConstructor.c
> > @@ -204,11 +204,6 @@ Bcm2711PciHostBridgeLibConstructor (
> >    } while (((Data & 0x30) != 0x030) && (Timeout));
> >    DEBUG ((DEBUG_VERBOSE, "PCIe link ready (status=%x) Timeout=%d\n", Data, Timeout));
> >
> > -  if ((Data & 0x30) != 0x30) {
> > -    DEBUG ((DEBUG_ERROR, "PCIe link not ready (status=%x)\n", Data));
> > -    return EFI_DEVICE_ERROR;
> > -  }
> > -
> >    if ((Data & 0x80) != 0x80) {
> >      DEBUG ((DEBUG_ERROR, "PCIe link not in RC mode (status=%x)\n", Data));
> >      return EFI_UNSUPPORTED;
> > diff --git a/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c
> > index 6d15e82fa2..b627e5730b 100644
> > --- a/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c
> > +++ b/Silicon/Broadcom/Bcm27xx/Library/Bcm2711PciSegmentLib/PciSegmentLib.c
> > @@ -105,6 +105,13 @@ PciSegmentLibGetConfigBase (
> >            return 0xFFFFFFFF;
> >        }
> >
> > +      /* Don't probe slots if the link is down */
> > +      Data = MmioRead32 (PCIE_REG_BASE + PCIE_MISC_PCIE_STATUS);
> > +      if ((Data & 0x30) != 0x30) {
> > +          DEBUG ((DEBUG_ERROR, "PCIe link not ready (status=%x)\n", Data));
> > +          return 0xFFFFFFFF;
> > +      }
> > +
> >        MmioWrite32 (PCIE_REG_BASE + PCIE_EXT_CFG_INDEX, Address);
> >        mPciSegmentLastAccess = Address;
> >      }
> > --
> > 2.13.7
> >