[U-Boot] [PATCH v2 15/17] Move eNET low-level initialisation into asm

[Wolfgang Denk]

Dear Graeme Russ,

In message <1251111477-15561-1-git-send-email-graeme.russ at gmail.com> you wrote:
> Allows earlier indication of boot progress by initialising the LEDs and
> Serial Port while the CPU is still in 16-bit (Real) mode

I have to admit that I am not a friend of moving C code to assembler.
This contradicts pretty basic principles of U-Boot design.

I can understand that you want diagnosis as early as possible, but 162
insertions versus 26 deletions is a clear indocation that something is
awfully wrong.


Are you absolutely sure this is a good idea?


> Version 2
>  - Fixed comments corrupted by accidental middle-mouse button press while
>    scrolling through code with mouse wheel
>  - Fixed mangled umlaut
>  - Fixed space before tab highlighted by Wolfgang Denk

You did not catch all of these, see below.

> diff --git a/board/eNET/eNET_start16.S b/board/eNET/eNET_start16.S
> index 48e4d83..31b33ec 100644
> --- a/board/eNET/eNET_start16.S
> +++ b/board/eNET/eNET_start16.S
...
> @@ -45,6 +44,65 @@ board_init16:
>  	movw	$0xdf00, %ax
>  	movw	%ax, %ds
>  
> +	/* Disable Watchdog */
> +	movl    $SC520_WDTMRCTL, %edi
> +	movw	$0x3333, %ax
> +	movw	%ax, (%di)
> +	movw	$0xcccc, %ax
> +	movw	%ax, (%di)
> +	movw	$0x3333, %ax
> +	movw	%ax, (%di)
> +
> +	/* Set CPU to 100MHz Speed */
> +	movb	$0x01, %al
> +	movl    $SC520_CPUCTL, %edi
> +	movb	%al, (%di)
> +
> +	/* wait at least one millisecond */
> +	movl	$0x1000,%ecx
> +cpuspddelay:
> +	loop 	cpuspddelay

SPACE + TAB ...

...
> +	/* wait for the UART clock to settle */
> +	movl	$0x10000,%ecx
> +uartdelay:
> +	loop 	uartdelay

SPACE + TAB ...


Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The so-called "desktop metaphor" of today's workstations  is  instead
an  "airplane-seat"  metaphor.  Anyone who has shuffled a lap full of
papers while seated between two portly passengers will recognize  the
difference -- one can see only a very few things at once.
                                                   - Fred Brooks, Jr.