tree 96adee8ae73a95035e7d523214c8674b026377ee
parent eec097d43100a8195fd4f678671ecd5d986dd675
author Bjorn Helgaas <bhelgaas@google.com> 1465766800 -0500
committer Bjorn Helgaas <bhelgaas@google.com> 1472131954 -0500

PCI: Add PTM clock granularity information

The PTM Control register (PCIe r3.1, sec 7.32.3) contains an Effective
Granularity field:

  This provides information relating to the expected accuracy of the PTM
  clock, but does not otherwise affect the PTM mechanism.

Set the Effective Granularity based on the PTM Root and any intervening PTM
Time Sources.

This does not set Effective Granularity for Root Complex Integrated
Endpoints because I don't know how to figure out clock granularity for
them.  The spec says:

  ... system software must set [Effective Granularity] to the value
  reported in the Local Clock Granularity field by the associated PTM
  Time Source.

but I don't know how to identify the associated PTM Time Source.  Normally
it's the upstream bridge, but an integrated endpoint has no upstream
bridge.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>