EmbeddedPkg/Lan9118Dxe: add PCD for negotiation timeout

Add a PCD for the link negotiation timeout so the platform can over-ride
the default value.

The code previously did 2000 iterations of the loop with a 2us stall, so
the code has been changed subtly to set the number of iterations equal
to the PCD value divided by the stall time.

Since the stall time has not changed, the default PCD value is set at
4000 so the original behaviour is not changed.

The problems were discovered when the ARM Juno Development Platform used
the "EFI Network" option with then LAN9118 driver.  It fails to boot the
first time and so the board drops back to Shell again:

  Warning: LAN9118 Driver in stopped state
  Link timeout in auto-negotiation.
  Lan9118: Auto Negociation not supported.
  EhcExecTransfer: transfer failed with 2
  EhcControlTransfer: error - Device Error, transfer - 2
  Buffer: EFI Hard Drive
  Booting EFI Misc Device
  Booting EFI Misc Device 1
  Booting EFI Hard Drive
  Booting EFI Network
  Warning: LAN9118 Driver not initialized
  Link timeout in auto-negotiation.
  Lan9118: Auto Negociation not supported.
  Booting EFI Internal Shell

Exiting Shell drops the user back to the Intel BDS UI.  Selecting
"Continue" then succeeds in booting from the EFI Network:

  Booting EFI Misc Device
  Booting EFI Misc Device 1
  Booting EFI Hard Drive
  Booting EFI Network
  ..MnpFreeTxBuf: Duplicated recycle report from SNP.
  MnpFreeTxBuf: Duplicated recycle report from SNP.
  [snip repeated errors]

Discussion on the edk2-devel mailing list [1] prompted Laszlo Ersek to
suggest the time taken for the NIC to negotiate was causing a problem.
He suggested the solution contained in this patch to provide a PCD
configurable by the platform.

The default PCD value does not work for Juno.  Setting the PCD to a
larger value works for Juno R0, R1 and R2.

[1] http://article.gmane.org/gmane.comp.bios.edk2.devel/7341

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/EmbeddedPkg/EmbeddedPkg.dec b/EmbeddedPkg/EmbeddedPkg.dec
index f557527281..cd0d96f79f 100644
--- a/EmbeddedPkg/EmbeddedPkg.dec
+++ b/EmbeddedPkg/EmbeddedPkg.dec
@@ -145,6 +145,7 @@
   # LAN9118 Ethernet Driver PCDs

   gEmbeddedTokenSpaceGuid.PcdLan9118DxeBaseAddress|0x0|UINT32|0x00000025

   gEmbeddedTokenSpaceGuid.PcdLan9118DefaultMacAddress|0x0|UINT64|0x00000026

+  gEmbeddedTokenSpaceGuid.PcdLan9118DefaultNegotiationTimeout|4000|UINT32|0x00000027

 

   #

   # Android FastBoot