obp/obp/dev/pci/hotplugdetect.fth

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\ Hypervisor Software File: hotplugdetect.fth
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id: @(#)hotplugdetect.fth 1.1 06/04/05 15:50:27
copyright: Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved
copyright: Use is subject to license terms.

headerless

\ Hot plug capability detection code to be used
\ in pci bridge code.

\ Called only if pcie capability is present. Called with the
\ offset of pcie capability register. Check pcie capability
\ for downstream port type, slot implemented and slot capability
\ for hotplug capability of the slot.
: pcie-hotplug-capable? ( offs -- flag )
   >r r@ 2+ my-w@                               ( pcie-cap ) ( R: offs )
   dup 4 >>  h# f and 6 = swap                  ( downstream? pcie-cap )
   h# 100 and and if                            (  ) ( R: offs )
      \ downstream port and slot implemented.
      \ check for hotplug capable bit in
      \ slot capability register
      r> d# 20 + my-l@ h# 40 and 0<>            ( flag )
   else
      \ upstream port or slot not implemented
      r> drop false                             ( false )
   then
;

\ Called only if pcie capability is present. Called with
\ the  offset  of pcie capability register. Check  pcie
\ capability for downstream port type and slot implemented.
: pcie-slot-implemented? ( offs -- flag )
   2+ my-w@                                     ( pcie-cap )
   dup 4 >>  h# f and 6 = swap                  ( downstream? pcie-cap )
   h# 100 and and                               ( flag )
;

\ Identifying a "hotplug-capable" bridge.  If capability
\ ptr is implemented then we search for the existence of
\ SHPC capability. If SHPC capability is present then we
\ say that the bridge supports hotplug. If no SHPC, then
\ if PCIE capability is present then we check the slot
\ capability for the presence of hotplug capability. If
\ present then it is hotplug capable.
: hotplug-capability? ( -- flag )
   shpc-capability-regs if true exit then
   pcie-capability-regs ?dup if                 ( offs )
      pcie-hotplug-capable?                     ( flag )
   else
      false                                     ( false )
   then
;

\ Since there is no way to tell if a pcie-pcix bridge has
\ physical  slot underneath it, we resort to finding if
\ the bridge  is  hotplug  capable and hence has slot
\ underneath. For a pcie port,it is possible to find if
\ there is physical slot implemented by looking at pci
\ express capability.
: slot-implemented? ( -- flag )
   \ SHPC Capability?
   shpc-capability-regs if true exit then
   pcie-capability-regs ?dup if                 ( offs )
      pcie-slot-implemented?                    ( flag )
   else                                         (  )
      false                                     ( false )
   then
;