[U-Boot] curious if XTRN_DECLARE_GLOBAL_DATA_PTR is still of value

[U-Boot] curious if XTRN_DECLARE_GLOBAL_DATA_PTR is still of value

[Robert P. J. Day]

  perusing the code related to the global data ptr and noticed in
common/board_f.c:

/*
 * Pointer to initial global data area
 *
 * Here we initialize it if needed.
 */
#ifdef XTRN_DECLARE_GLOBAL_DATA_PTR
#undef  XTRN_DECLARE_GLOBAL_DATA_PTR
#define XTRN_DECLARE_GLOBAL_DATA_PTR    /* empty = allocate here */
DECLARE_GLOBAL_DATA_PTR = (gd_t *) (CONFIG_SYS_INIT_GD_ADDR);
#else
DECLARE_GLOBAL_DATA_PTR;
#endif

  i was curious to see if anything took advantage of that and the only
other place in the code that referred to that was in
arch/powerpc/include/asm/global_data.h:

#if 1
#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r2")
#else /* We could use plain global data, but the resulting code is bigger */
#define XTRN_DECLARE_GLOBAL_DATA_PTR    extern
#define DECLARE_GLOBAL_DATA_PTR     XTRN_DECLARE_GLOBAL_DATA_PTR \
                                    gd_t *gd
#endif

  and given the "#if 1", it's pretty clear powerpc doesn't care about
that, and that file common/board_f.c is the only place i can see in
the entire code base that refers to CONFIG_SYS_INIT_GD_ADDR.

  so are people still taking advantage of this in some way?

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================

[U-Boot] curious if XTRN_DECLARE_GLOBAL_DATA_PTR is still of value

[Simon Glass]

Hi Robert,

On 16 December 2015 at 05:02, Robert P. J. Day <rpjday@crashcourse.ca> wrote:
>
>   perusing the code related to the global data ptr and noticed in
> common/board_f.c:
>
> /*
>  * Pointer to initial global data area
>  *
>  * Here we initialize it if needed.
>  */
> #ifdef XTRN_DECLARE_GLOBAL_DATA_PTR
> #undef  XTRN_DECLARE_GLOBAL_DATA_PTR
> #define XTRN_DECLARE_GLOBAL_DATA_PTR    /* empty = allocate here */
> DECLARE_GLOBAL_DATA_PTR = (gd_t *) (CONFIG_SYS_INIT_GD_ADDR);
> #else
> DECLARE_GLOBAL_DATA_PTR;
> #endif
>
>   i was curious to see if anything took advantage of that and the only
> other place in the code that referred to that was in
> arch/powerpc/include/asm/global_data.h:
>
> #if 1
> #define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r2")
> #else /* We could use plain global data, but the resulting code is bigger */
> #define XTRN_DECLARE_GLOBAL_DATA_PTR    extern
> #define DECLARE_GLOBAL_DATA_PTR     XTRN_DECLARE_GLOBAL_DATA_PTR \
>                                     gd_t *gd
> #endif
>
>   and given the "#if 1", it's pretty clear powerpc doesn't care about
> that, and that file common/board_f.c is the only place i can see in
> the entire code base that refers to CONFIG_SYS_INIT_GD_ADDR.
>
>   so are people still taking advantage of this in some way?

Not that I know of. Looks like it could be cleaned up.

Regards,
Simon