ArmPlatformPkg: Reserving framebuffer at build

Currently framebuffer memory is either reserved in special VRAM or
dynamically allocated using boot services memory allocation functions.
When allocated using boot services calls the memory has to be allocated
as EfiBootServicesData. Unfortunately failures have been seen with this
case.  There is also an unfortunate lack of control on the placement of
the framebuffer.

This change introduces two PCDs, PcdArmLcdFrameBufferBase and
PcdArmLcdFrameBufferSize which enable build time reservation of the
framebuffer, avoiding the need to allocate dynamically. This allows
the framebuffer to appear as "I/O memory" outside of the normal RAM
map, which is similar to the "VRAM" case.

This change has no impact on current code, only enables the option
of build time reservation of framebuffers.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Girish Pathak <girish.pathak@arm.com>
Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

diff --git a/ArmPlatformPkg/ArmPlatformPkg.dec b/ArmPlatformPkg/ArmPlatformPkg.dec
index 372cf2dc09586ab41d97b915b0601ea495161d5f..46f6c60066679dfd09d1cfd4689c1ee882b11ecc 100644 (file)
--- a/ArmPlatformPkg/ArmPlatformPkg.dec
+++ b/ArmPlatformPkg/ArmPlatformPkg.dec
@@ -89,6 +89,11 @@
   gArmPlatformTokenSpaceGuid.PcdPL111LcdBase|0x0|UINT32|0x00000026\r
   gArmPlatformTokenSpaceGuid.PcdArmHdLcdBase|0x0|UINT32|0x00000027\r
 \r
+  ## Default size for display modes upto 1920x1080 (1920 * 1080 * 4 Bytes Per Pixel)\r
+  gArmPlatformTokenSpaceGuid.PcdArmLcdDdrFrameBufferSize|0x7E9000|UINT32|0x00000043\r
+  ## If set, framebuffer memory will be reserved and mapped in the system RAM\r
+  gArmPlatformTokenSpaceGuid.PcdArmLcdDdrFrameBufferBase|0x0|UINT64|0x00000044\r
+\r
   ## PL180 MCI\r
   gArmPlatformTokenSpaceGuid.PcdPL180SysMciRegAddress|0x00000000|UINT32|0x00000028\r
   gArmPlatformTokenSpaceGuid.PcdPL180MciBaseAddress|0x00000000|UINT32|0x00000029\r