arm: Support a separate stack for VPL

VPL has the same needs as TPL in situations where the stack is at the
top of SRAM. Add an option for this and implement it for arm

Series-changes: 2
- Reply on existing CONFIG_VAL() to select the VPL stack
- Correct reference to TPL when VPL was intended

Series-changes: 3
- Use 'phase' instead of 'stage' in VPL_STACK
- Split off into its own 'vbh' series

Series-to: u-boot
Series-version: 3
Series-cc: jonas
Cover-letter:
xPL-stack cleanup
This series was split from the VBE part H series. It adjusts the logic
for selecting the top of the stack so that it is more consistent across
xPL phases.
END

Signed-off-by: Simon Glass <sjg@chromium.org>

common/spl/Kconfig.vpl

@@ -266,6 +266,20 @@ config VPL_MAX_SIZE
 	  The maximum size (in bytes) of the TPL stage. This size is determined
 	  by the amount of internal SRAM memory.
 
+config VPL_HAVE_INIT_STACK
+	bool "VPL requires a initial, fixed, stack-pointer location"
+	help
+	  Enable if the VPL phase should not use inherit its initial
+	  stack-pointer from the settings for U-Boot proper, but should set
+	  its own value.
+
+config VPL_STACK
+	hex "Address of the initial stack-pointer for the VPL phase"
+	depends on VPL_HAVE_INIT_STACK
+	help
+	  The address of the initial stack-pointer for the VPL phase
+	  Usually this will be the (aligned) top-of-stack.
+
 config VPL_BINMAN_SYMBOLS
 	bool "Declare binman symbols in VPL"
 	depends on VPL_FRAMEWORK && BINMAN