u-boot.git/examples/standalone, branch v2020.04

Merge git://git.denx.de/u-boot-riscv

2019-01-16T03:05:05+00:00

1. Improve cache implementation.
2. Fix and improve standalone applications

kbuild: add .SECONDARY special target to scripts/Kbuild.include

2019-01-15T20:28:53+00:00

Based on the following Linux commits:

 - 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove
   .PRECIOUS markers")

 - 8e9b61b293d9 ("kbuild: move .SECONDARY special target to
   Kbuild.include")

GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.

Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped

A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.

  .SECONDARY
    Prerequisites of this special target are treated as intermediate
    files but are never automatically deleted.

  .PRECIOUS
    When make is interrupted during execution, it may delete the target
    file it is updating if the file was modified since make started.
    If you mark the file as precious, make will never delete the file
    if interrupted.

Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.

The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.

.SECONDARY with no prerequisites causes all targets to be treated as
secondary. This agrees the policy of Kbuild.

scripts/Kbuild.include seems a suitable place to add it because it is
included from almost all sub-makes.

Signed-off-by: Masahiro Yamada

riscv: support standalone applications on RV64I systems

2019-01-15T01:36:31+00:00

Add an implementation of EXPORT_FUNC() for RV64I systems to support them
in standalone applications.

Signed-off-by: Lukas Auer 
Reviewed-by: Bin Meng 
Tested-by: Bin Meng

riscv: replace use of callee-saved register in standalone

2019-01-15T01:36:31+00:00

Register x19 (s3) is a callee-saved register. It must not be used to
load and jump to exported functions without saving it beforehand.
Replace it with t0, a temporary and caller-saved register.

Change the code comment to reflect this and fix it to correctly list gp
as the register with the pointer to global data.

Signed-off-by: Lukas Auer 
Reviewed-by: Bin Meng 
Tested-by: Bin Meng

riscv: remove RISC-V standalone linker script

2019-01-15T01:36:31+00:00

Standalone applications do not require a separate linker script and can
use the default linker script of the compiler instead. Remove the RISC-V
standalone linker script.

Signed-off-by: Lukas Auer 
Reviewed-by: Bin Meng 
Tested-by: Bin Meng

spi: Remove used spi_init

2018-11-27T15:36:53+00:00

spi_init used in some areas in tree, but the respective
drivers will remove in future patches.

So remove the same instances.

Signed-off-by: Jagan Teki

MIPS: fix linking of standalone programs

2018-11-18T15:02:23+00:00

Use the global MIPS specific u-boot.lds for linking standalone programs
instead of the outdated ones in examples/standalone/. Also pass --gc-sections
in LDFLAGS_STANDALONE to optimize the size of standalone programs.
Finally remove the deprecated config.mk files in arch/mips/cpu/mips[32,64]/.

Signed-off-by: Daniel Schwierzeck

Kbuild: standalone: do not ignore platform-specific OBJCOPYFLAGS

2018-11-18T15:02:23+00:00

Currently the OBJCOPYFLAGS are cleared when assigning "-O srec"
or "-O binary" for standalone programs. All flags set by arch-specific
Makefiles are lost. This is bad if an arch demands arch-specific
flags for the objcopy step.

Signed-off-by: Daniel Schwierzeck 
Reviewed-by: Tom Rini

Kbuild: add LDFLAGS_STANDALONE

2018-11-18T15:02:23+00:00

Introduce a new Makefile variable for passing LDFLAGS to standalone
programs. Currently the variable CONFIG_STANDALONE_LOAD_ADDR is
misued on some archs to pass a specific linker script.

Signed-off-by: Daniel Schwierzeck 
Reviewed-by: Tom Rini 
Reviewed-by: Rick Chen

SPDX: Convert all of our single license tags to Linux Kernel style

2018-05-07T13:34:12+00:00

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini