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author | Simon Glass <sjg@chromium.org> | 2015-05-04 11:31:03 -0600 |
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committer | Simon Glass <sjg@chromium.org> | 2015-05-14 18:49:34 -0600 |
commit | 5519912164698b634893913b4408fee736d01d06 (patch) | |
tree | 055c30565c23a1c623a5013be9590e111e8d3a6f | |
parent | 5a942a1527766c27674ea71222a2a98982e8a661 (diff) | |
download | u-boot-imx-5519912164698b634893913b4408fee736d01d06.zip u-boot-imx-5519912164698b634893913b4408fee736d01d06.tar.gz u-boot-imx-5519912164698b634893913b4408fee736d01d06.tar.bz2 |
arm: Add a prototype for save_boot_params_ret()
It is convenient for some boards to implement save_boot_params() in C rather
than assembler. Provide a way to return in this case.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>
-rw-r--r-- | arch/arm/include/asm/system.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index fe10335..760e8ab 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -159,6 +159,22 @@ void flush_l3_cache(void); * void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3); */ +/** + * save_boot_params_ret() - Return from save_boot_params() + * + * If you provide save_boot_params(), then you should jump back to this + * function when done. Try to preserve all registers. + * + * If your implementation of save_boot_params() is in C then it is acceptable + * to simply call save_boot_params_ret() at the end of your function. Since + * there is no link register set up, you cannot just exit the function. U-Boot + * will return to the (initialised) value of lr, and likely crash/hang. + * + * If your implementation of save_boot_params() is in assembler then you + * should use 'b' or 'bx' to return to save_boot_params_ret. + */ +void save_boot_params_ret(void); + #define isb() __asm__ __volatile__ ("" : : : "memory") #define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t"); |