[OpenBIOS] [PATCH] vga.fs: add support for QEMU PCI MMIO register access

[Mark Cave-Ayland]

Currently the driver works by using the legacy VGA ioports for programming
the display. However this makes it much harder to configure e.g. multiple
displays or VGA devices behind multiple PCI bridges.

If building for QEMU, default to using the QEMU PCI MMIO registers to program
the display.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>
---
 drivers/vga.fs |   85 ++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 68 insertions(+), 17 deletions(-)

diff --git a/drivers/vga.fs b/drivers/vga.fs
index cbfa46c..d39b062 100644
--- a/drivers/vga.fs
+++ b/drivers/vga.fs
@@ -47,6 +47,22 @@ fcode-version3
 : ioc! ioc!-xt execute ;
 : iow! iow!-xt execute ;
 
+" le-w!" (find-xt) value le-w!-xt
+
+: le-w! le-w!-xt execute ;
+
+\
+\ PCI
+\
+
+" pci-bar>pci-addr" (find-xt) value pci-bar>pci-addr-xt
+: pci-bar>pci-addr pci-bar>pci-addr-xt execute ;
+
+h# 10 constant cfg-bar0    \ Framebuffer BAR
+h# 18 constant cfg-bar2    \ QEMU MMIO ioport BAR
+-1 value fb-addr
+-1 value mmio-addr
+
 \
 \ VGA registers
 \
@@ -55,12 +71,22 @@ h# 3c0 constant vga-addr
 h# 3c8 constant dac-write-addr
 h# 3c9 constant dac-data-addr
 
+defer vga-ioc!
+
+: vga-legacy-ioc!  ( val addr )
+  ioc! 
+;
+
+: vga-mmio-ioc!  ( val addr )
+  h# 3c0 - h# 400 + mmio-addr + c!
+;
+
 : vga-color!  ( r g b index -- )
   \ Set the VGA colour registers
-  dac-write-addr ioc! rot
-  2 >> dac-data-addr ioc! swap
-  2 >> dac-data-addr ioc!
-  2 >> dac-data-addr ioc!
+  dac-write-addr vga-ioc! rot
+  2 >> dac-data-addr vga-ioc! swap
+  2 >> dac-data-addr vga-ioc!
+  2 >> dac-data-addr vga-ioc!
 ;
 
 \
@@ -86,17 +112,23 @@ h# 1 constant VBE_DISPI_ENABLED
 \ Bochs VBE register writes
 \
 
-: vbe-iow!  ( val addr -- )
+defer vbe-iow!
+
+: vbe-legacy-iow!  ( val addr -- )
   h# 1ce iow!
   h# 1d0 iow!
 ;
 
+: vbe-mmio-iow!  ( val addr -- )
+  1 lshift h# 500 + mmio-addr + cr .s cr le-w!
+;
+
 \
 \ Initialise Bochs VBE mode
 \
 
 : vbe-init  ( -- )
-  h# 0 vga-addr ioc!    \ Enable blanking
+  h# 0 vga-addr vga-ioc!    \ Enable blanking
   VBE_DISPI_DISABLED VBE_DISPI_INDEX_ENABLE vbe-iow!
   h# 0 VBE_DISPI_INDEX_X_OFFSET vbe-iow!
   h# 0 VBE_DISPI_INDEX_Y_OFFSET vbe-iow!
@@ -104,20 +136,14 @@ h# 1 constant VBE_DISPI_ENABLED
   openbios-video-height VBE_DISPI_INDEX_YRES vbe-iow!
   depth-bits VBE_DISPI_INDEX_BPP vbe-iow!
   VBE_DISPI_ENABLED VBE_DISPI_INDEX_ENABLE vbe-iow!
-  h# 0 vga-addr ioc!
-  h# 20 vga-addr ioc!   \ Disable blanking
+  h# 0 vga-addr vga-ioc!
+  h# 20 vga-addr vga-ioc!   \ Disable blanking
 ;
 
 \
-\ PCI
+\ PCI BAR mapping
 \
 
-" pci-bar>pci-addr" (find-xt) value pci-bar>pci-addr-xt
-: pci-bar>pci-addr pci-bar>pci-addr-xt execute ;
-
-h# 10 constant cfg-bar0    \ Framebuffer BAR
--1 value fb-addr
-
 : map-fb ( -- )
   cfg-bar0 pci-bar>pci-addr if   \ ( pci-addr.lo pci-addr.mid pci-addr.hi size )
     " pci-map-in" $call-parent
@@ -125,6 +151,32 @@ h# 10 constant cfg-bar0    \ Framebuffer BAR
   then
 ;
 
+: map-mmio ( -- )
+  cfg-bar2 pci-bar>pci-addr if   \ ( pci-addr.lo pci-addr.mid pci-addr.hi size )
+    " pci-map-in" $call-parent
+    to mmio-addr
+  then
+;
+
+\
+\ Legacy IO port or QEMU MMIO accesses
+\
+\ legacy: use standard VGA ioport registers
+\ MMIO: use QEMU PCI MMIO VGA registers
+\
+\ If building for QEMU, default to MMIO access since it allows
+\ programming of the VGA card regardless of its position in the
+\ PCI topology
+\
+
+[IFDEF] CONFIG_QEMU
+['] vga-mmio-ioc! to vga-ioc!
+['] vbe-mmio-iow! to vbe-iow!
+[ELSE]
+['] vga-legacy-ioc! to vga-ioc!
+['] vbe-legacy-iow! to vbe-iow!
+[THEN]
+
 \
 \ Publically visible words
 \
@@ -181,6 +233,7 @@ headerless
 \
 
 : qemu-vga-driver-install ( -- )
+  map-mmio vbe-init
   fb-addr -1 = if
     map-fb fb-addr to frame-buffer-adr
     default-font set-font
@@ -193,8 +246,6 @@ headerless
 ;
 
 : qemu-vga-driver-init
-
-  vbe-init
   openbios-video-width encode-int " width" property
   openbios-video-height encode-int " height" property
   depth-bits encode-int " depth" property
-- 
1.7.10.4