[SLOF] [PATCH] pci: Avoid 32-bit prefetchable memory area if possible

[Thomas Huth]

PCI bridges can only have one prefetchable memory area. If we are
already using 64-bit prefetchable memory regions, we can not use
a dedicated 32-bit prefetchable memory region anymore. In that
case the 32-bit BARs should all be located in the 32-bit non-
prefetchable memory space instead.

Signed-off-by: Thomas Huth <thuth at redhat.com>
---
 board-qemu/slof/pci-phb.fs | 16 +++++++++++-----
 slof/fs/pci-properties.fs  |  7 ++++++-
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/board-qemu/slof/pci-phb.fs b/board-qemu/slof/pci-phb.fs
index b7bf9cf..926efba 100644
--- a/board-qemu/slof/pci-phb.fs
+++ b/board-qemu/slof/pci-phb.fs
@@ -253,12 +253,9 @@ setup-puid
             THEN
          ENDOF
          2000000 OF                             \ 32-bit memory space?
-            decode-64 pci-next-mem !            \ Decode mem base address
+            decode-64 dup >r pci-next-mmio !    \ Decode base address
             decode-64 drop                      \ Forget the parent address
-            decode-64 2 / dup >r                \ Decode and calc size/2
-            pci-next-mem @ + dup pci-max-mem !  \ and calc max mem address
-            dup pci-next-mmio !                 \ which is the same as MMIO base
-            r> + pci-max-mmio !                 \ calc max MMIO address
+            decode-64 r> + pci-max-mmio !       \ calc max MMIO address
          ENDOF
          3000000 OF                             \ 64-bit memory space?
             decode-64 dup >r pci-next-mem64 !
@@ -270,6 +267,15 @@ setup-puid
    ( prop-addr prop-len )
    2drop
 
+   \ If we do not have 64-bit prefetchable memory, split the 32-bit space:
+   pci-next-mem64 @ 0= IF
+      pci-next-mmio @ pci-next-mem !            \ Start of 32-bit prefetchable
+      pci-max-mmio @ pci-next-mmio @ - 2 /      \ Calculate new size
+      pci-next-mmio @ +                         \ The middle of the area
+      dup pci-max-mem !
+      pci-next-mmio !
+   THEN
+
    phb-debug? IF
      ." pci-next-io   = " pci-next-io @ . cr
      ." pci-max-io    = " pci-max-io  @ . cr
diff --git a/slof/fs/pci-properties.fs b/slof/fs/pci-properties.fs
index b7bb534..6f8f013 100644
--- a/slof/fs/pci-properties.fs
+++ b/slof/fs/pci-properties.fs
@@ -159,7 +159,12 @@
 \ Setup a prefetchable 32bit BAR and return its size
 : assign-mem32-bar ( bar-addr -- 4 )
         dup pci-bar-size-mem32          \ fetch size
-        pci-next-mem                    \ var to change
+        \ Do we have a dedicated 32-bit prefetchable area? If not, use MMIO
+        pci-next-mem @ IF
+            pci-next-mem
+        ELSE
+            pci-next-mmio
+        THEN
         assign-bar-value32              \ and set it all
 ;
 
-- 
1.8.3.1