[U-Boot] [PATCH v3 2/8] board_init_f_mem(): Don't require memset()

[Albert ARIBAUD]

Hello Simon,

On Sat, 17 Oct 2015 15:06:55 -0600, Simon Glass <sjg at chromium.org>
wrote:
> Unfortunately memset() is not always available, so provide a substitute when
> needed.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
> 
> Changes in v3: None
> Changes in v2:
> - Add comments as to why this is needed, deal with arch-specific memset()
> 
>  common/init/board_init.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/common/init/board_init.c b/common/init/board_init.c
> index e7ebca7..c113a80 100644
> --- a/common/init/board_init.c
> +++ b/common/init/board_init.c
> @@ -11,6 +11,16 @@
>  
>  DECLARE_GLOBAL_DATA_PTR;
>  
> +/*
> + * It isn't trivial to figure out whether memcpy() exists. The arch-specific
> + * memcpy() is not normally available in SPL due to code size.
> + */
> +#if !defined(CONFIG_SPL_BUILD) || \
> +		(defined(CONFIG_SPL_LIBGENERIC_SUPPORT) && \
> +		!defined(CONFIG_USE_ARCH_MEMSET))
> +#define _USE_MEMCPY
> +#endif
> +
>  /* Unfortunately x86 can't compile this code as gd cannot be assigned */
>  #ifndef CONFIG_X86
>  __weak void arch_setup_gd(struct global_data *gd_ptr)
> @@ -22,6 +32,9 @@ __weak void arch_setup_gd(struct global_data *gd_ptr)
>  ulong board_init_f_mem(ulong top)
>  {
>  	struct global_data *gd_ptr;
> +#ifndef _USE_MEMCPY
> +	int *ptr, *end;
> +#endif
>  
>  	/* Leave space for the stack we are running with now */
>  	top -= 0x40;
> @@ -29,7 +42,12 @@ ulong board_init_f_mem(ulong top)
>  	top -= sizeof(struct global_data);
>  	top = ALIGN(top, 16);
>  	gd_ptr = (struct global_data *)top;
> +#ifdef _USE_MEMCPY
>  	memset(gd_ptr, '\0', sizeof(*gd));
> +#else
> +	for (ptr = (int *)gd_ptr, end = (int *)(gd_ptr + 1); ptr < end; )

Nitpick here: There is little point in naming a variable just for
it to be set and used once. Without 'end', the compiler will be just as
fine if ptr is directly tested against (int *)(gd_ptr + 1), and human
readers won't wonder why 'end' was created.

> +		*ptr++ = 0;
> +#endif
>  	arch_setup_gd(gd_ptr);
>  
>  #if defined(CONFIG_SYS_MALLOC_F)
> -- 
> 2.6.0.rc2.230.g3dd15c0

Amicalement,
-- 
Albert.