[SLOF] [PATCH slof v4 1/5] pci-phb: Reimplement dma-map-in/out
Alexey Kardashevskiy
aik at ozlabs.ru
Wed Dec 4 14:21:34 AEDT 2019
The immediate problem with the code is that it relies on memory allocator
aligning addresses to the size. This is true for SLOF but not for GRUB
and in unaligned situations we end up mapping more pages than bm-alloc
allocated.
This fixes the problem by calculating aligned DMA size before calling
bm-alloc.
While at this, simplify the code by removing global variables. Also
replace 1000/fff (the default 4K IOMMU page size) with tce-ps/mask.
Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
---
Changes:
v4:
* fixed code comments, tab/spaces
* fixed bm-alloc failure handling
---
board-qemu/slof/pci-phb.fs | 95 ++++++++++++++++----------------------
1 file changed, 39 insertions(+), 56 deletions(-)
diff --git a/board-qemu/slof/pci-phb.fs b/board-qemu/slof/pci-phb.fs
index 06729bcf77a0..2a003fca4a30 100644
--- a/board-qemu/slof/pci-phb.fs
+++ b/board-qemu/slof/pci-phb.fs
@@ -14,6 +14,8 @@
0 VALUE phb-debug?
+1000 CONSTANT tce-ps \ Default TCE page size is 4K
+tce-ps 1- CONSTANT tce-mask
." Populating " pwd cr
@@ -86,17 +88,17 @@ setup-puid
: dma-alloc ( size -- virt )
phb-debug? IF cr ." dma-alloc called: " .s cr THEN
- fff + fff not and \ Align size to next 4k boundary
+ tce-ps #aligned
alloc-mem
\ alloc-mem always returns aligned memory - double check just to be sure
- dup fff and IF
+ dup tce-mask and IF
." Warning: dma-alloc got unaligned memory!" cr
THEN
;
: dma-free ( virt size -- )
phb-debug? IF cr ." dma-free called: " .s cr THEN
- fff + fff not and \ Align size to next 4k boundary
+ tce-ps #aligned
free-mem
;
@@ -107,10 +109,6 @@ setup-puid
0 VALUE dma-window-size \ Size of the window
0 VALUE bm-handle \ Bitmap allocator handle
-0 VALUE my-virt
-0 VALUE my-size
-0 VALUE dev-addr
-0 VALUE tmp-dev-addr
\ Read helper variables (LIOBN, DMA window base and size) from the
\ "ibm,dma-window" property. This property can be either located
@@ -130,11 +128,11 @@ setup-puid
decode-64 TO dma-window-size
2drop
bm-handle 0= IF
- dma-window-base dma-window-size 1000 bm-allocator-init to bm-handle
+ dma-window-base dma-window-size tce-ps bm-allocator-init to bm-handle
\ Sometimes the window-base appears as zero, that does not
\ go well with NULL pointers. So block this address
dma-window-base 0= IF
- bm-handle 1000 bm-alloc drop
+ bm-handle tce-ps bm-alloc drop
THEN
THEN
;
@@ -145,69 +143,54 @@ setup-puid
0 TO dma-window-size
;
-\ We assume that firmware never maps more than the whole dma-window-size
-\ so we cheat by calculating the remainder of addr/windowsize instead
-\ of taking care to maintain a list of assigned device addresses
-: dma-virt2dev ( virt -- devaddr )
- dma-window-size mod dma-window-base +
-;
+\ grub does not align allocated addresses to the size so when mapping,
+\ we might need to ask bm-alloc for an extra IOMMU page
+: dma-align ( size virt -- aligned-size ) tce-mask and + tce-ps #aligned ;
+: dma-trunc ( addr -- addr&~fff ) tce-mask not and ;
: dma-map-in ( virt size cachable? -- devaddr )
phb-debug? IF cr ." dma-map-in called: " .s cr THEN
(init-dma-window-vars)
- drop ( virt size )
-
- to my-size
- to my-virt
- bm-handle my-size bm-alloc
- to dev-addr
- dev-addr 0 < IF
- ." Bitmap allocation Failed " dev-addr .
- FALSE EXIT
+ drop
+ over dma-align ( virt size ) \ size is aligned now
+ tuck ( size virt size )
+ bm-handle swap bm-alloc ( size virt dev-addr ) \ dev-addr is aligned
+ dup 0 < IF
+ ." Bitmap allocation Failed "
+ 3drop
+ 0 EXIT
THEN
- dev-addr to tmp-dev-addr
- my-virt my-size
- bounds dup >r ( v+s virt R: virt )
- swap fff + fff not and \ Align end to next 4k boundary
- swap fff not and ( v+s' virt' R: virt )
+ swap ( size dev-addr virt )
+ 2dup tce-mask and or >r \ add page offset to the return value
+
+ dma-trunc 3 OR \ Truncate and add read and write perm
+ rot ( dev-addr virt size r: dev-addr )
+ 0
?DO
- \ ." mapping " i . cr
- dma-window-liobn \ liobn
- tmp-dev-addr \ ioba
- i 3 OR \ Make a read- & writeable TCE
- ( liobn ioba tce R: virt )
+ 2dup dma-window-liobn -rot ( dev-addr virt liobn dev-addr virt r: dev-addr )
hv-put-tce ABORT" H_PUT_TCE failed"
- tmp-dev-addr 1000 + to tmp-dev-addr
- 1000 +LOOP
- r> drop
- my-virt FFF and dev-addr or
+ tce-ps + swap tce-ps + swap ( dev-addr' virt' r: dev-addr )
+ tce-ps +LOOP
(clear-dma-window-vars)
+ 2drop
+ r>
;
: dma-map-out ( virt devaddr size -- )
phb-debug? IF cr ." dma-map-out called: " .s cr THEN
(init-dma-window-vars)
- to my-size
- to dev-addr
- to my-virt
- dev-addr fff not and to dev-addr
- dev-addr to tmp-dev-addr
-
- my-virt my-size ( virt size )
- bounds ( v+s virt )
- swap fff + fff not and \ Align end to next 4k boundary
- swap fff not and ( v+s' virt' )
+ rot drop ( devaddr size )
+ over dma-align
+ swap dma-trunc swap ( devaddr-trunc size-extended )
+ 2dup bm-handle -rot bm-free
+ 0
?DO
- \ ." unmapping " i . cr
- dma-window-liobn \ liobn
- tmp-dev-addr \ ioba
- i \ Lowest bits not set => invalid TCE
- ( liobn ioba tce )
+ dup 0 dma-window-liobn -rot
hv-put-tce ABORT" H_PUT_TCE failed"
- tmp-dev-addr 1000 + to tmp-dev-addr
- 1000 +LOOP
- bm-handle dev-addr my-size bm-free
+ tce-ps +
+ tce-ps +LOOP
+ drop
(clear-dma-window-vars)
;
--
2.17.1
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