Merge patch series "Tidy up use of 'SPL' and CONFIG_SPL_BUILD"

Simon Glass <sjg@chromium.org> says:

When the SPL build-phase was first created it was designed to solve a
particular problem (the need to init SDRAM so that U-Boot proper could
be loaded). It has since expanded to become an important part of U-Boot,
with three phases now present: TPL, VPL and SPL

Due to this history, the term 'SPL' is used to mean both a particular
phase (the one before U-Boot proper) and all the non-proper phases.
This has become confusing.

For a similar reason CONFIG_SPL_BUILD is set to 'y' for all 'SPL'
phases, not just SPL. So code which can only be compiled for actual SPL,
for example, must use something like this:

   #if defined(CONFIG_SPL_BUILD) && !defined(CONFIG_TPL_BUILD)

In Makefiles we have similar issues. SPL_ has been used as a variable
which expands to either SPL_ or nothing, to chose between options like
CONFIG_BLK and CONFIG_SPL_BLK. When TPL appeared, a new SPL_TPL variable
was created which expanded to 'SPL_', 'TPL_' or nothing. Later it was
updated to support 'VPL_' as well.

This series starts a change in terminology and usage to resolve the
above issues:

- The word 'xPL' is used instead of 'SPL' to mean a non-proper build
- A new CONFIG_XPL_BUILD define indicates that the current build is an
  'xPL' build
- The existing CONFIG_SPL_BUILD is changed to mean SPL; it is not now
  defined for TPL and VPL phases
- The existing SPL_ Makefile variable is renamed to SPL_
- The existing SPL_TPL Makefile variable is renamed to PHASE_

It should be noted that xpl_phase() can generally be used instead of
the above CONFIGs without a code-space or run-time penalty.

This series does not attempt to convert all of U-Boot to use this new
terminology but it makes a start. In particular, renaming spl.h and
common/spl seems like a bridge too far at this point.

The series is fully bisectable. It has also been checked to ensure there
are no code-size changes on any commit.

drivers/block/Makefile

@@ -3,20 +3,20 @@
 # (C) Copyright 2000-2007
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
-obj-$(CONFIG_$(SPL_TPL_)BLK) += blk-uclass.o
+obj-$(CONFIG_$(PHASE_)BLK) += blk-uclass.o
 
-ifndef CONFIG_$(SPL_)BLK
+ifndef CONFIG_$(XPL_)BLK
 obj-$(CONFIG_SPL_LEGACY_BLOCK) += blk_legacy.o
 endif
 
-ifndef CONFIG_SPL_BUILD
+ifndef CONFIG_XPL_BUILD
 obj-$(CONFIG_IDE) += ide.o
 obj-$(CONFIG_RKMTD) += rkmtd.o
 endif
 obj-$(CONFIG_SANDBOX) += sandbox.o host-uclass.o host_dev.o
-obj-$(CONFIG_$(SPL_TPL_)BLOCK_CACHE) += blkcache.o
-obj-$(CONFIG_$(SPL_TPL_)BLKMAP) += blkmap.o
-obj-$(CONFIG_$(SPL_TPL_)BLKMAP) += blkmap_helper.o
+obj-$(CONFIG_$(PHASE_)BLOCK_CACHE) += blkcache.o
+obj-$(CONFIG_$(PHASE_)BLKMAP) += blkmap.o
+obj-$(CONFIG_$(PHASE_)BLKMAP) += blkmap_helper.o
 
 obj-$(CONFIG_EFI_MEDIA) += efi-media-uclass.o
 obj-$(CONFIG_EFI_MEDIA_SANDBOX) += sb_efi_media.o