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arm: Add a prototype for save_boot_params_ret()

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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>
This commit is contained in:
Simon Glass 2015-05-04 11:31:03 -06:00
parent 5a942a1527
commit 5519912164
1 changed files with 16 additions and 0 deletions
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16
arch/arm/include/asm/system.h
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@ -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");